Expression balances of structural genes in shikimate and flavonoid biosynthesis cause a difference in proanthocyanidin accumulation in persimmon (Diospyros kaki Thunb.) fruit.
Akagi Takashi,Ikegami Ayako,Suzuki Yasuhiko,Yoshida Junya,Yamada Masahiko,Sato Akihiko,Yonemori Keizo
Persimmon fruits accumulate a large amount of proanthocyanidin (PA) during development. Fruits of pollination-constant and non-astringent (PCNA) type mutants lose their ability to produce PA at an early stage of fruit development, while fruits of the normal (non-PCNA) type remain rich in PA until fully ripened. To understand the molecular mechanism for this difference, we isolated the genes involved in PA accumulation that are differentially expressed between PCNA and non-PCNA, and confirmed their correlation with PA content and composition. The expression of structural genes of the shikimate and flavonoid biosynthetic pathways and genes encoding transferases homologous to those involved in the accumulation of phenolic compounds were downregulated coincidentally only in the PCNA type. Analysis of PA composition using the phloroglucinol method suggested that the amounts of epigallocatechin and its 3-O-gallate form were remarkably low in the PCNA type. In the PCNA type, the genes encoding flavonoid 3'5' hydroxylase (F3'5'H) and anthocyanidin reductase (ANR) for epigallocatechin biosynthesis showed remarkable downregulation, despite the continuous expression level of their competitive genes, flavonoid 3' hydroxylation (F3'H) and leucoanthocyanidin reductase (LAR). We also confirmed that the relative expression levels of F3'5'H to F3'H, and ANR to LAR, were considerably higher, and the PA composition corresponded to the seasonal expression balances in both types. These results suggest that expressions of F3'5'H and ANR are important for PA accumulation in persimmon fruit. Lastly, we tested enzymatic activity of recombinant DkANR in vitro, which is thought to be an important enzyme for PA accumulation in persimmon fruits.
Genetic and Phytochemical Characterization of Lettuce Flavonoid Biosynthesis Mutants.
Gurdon Csanad,Poulev Alexander,Armas Isabel,Satorov Shukhratdzhon,Tsai Meg,Raskin Ilya
We previously developed red lettuce (Lactuca sativa L.) cultivars with high flavonoid and phenolic acid content and demonstrated their anti-diabetic effect. Here we report on developing three fertile and true-breeding lettuce lines enriched with flavonoids with reported beneficial health effects. These lines were identified in a segregating population of EMS-mutagenized red lettuce and characterized biochemically and genetically. Change in red coloration was used as a visual indicator of a mutation in a flavonoid pathway gene, leading to accumulation of flavonoid precursors of red anthocyanins. Pink-green kaempferol overproducing kfoA and kfoB mutants accumulated kaempferol to 0.6-1% of their dry weight, higher than in any vegetable reported. The yellow-green naringenin chalcone overproducing mutant (nco) accumulated naringenin chalcone, not previously reported in lettuce, to 1% dry weight, a level only observed in tomato peel. Kfo plants carried a mutation in the FLAVONOID-3' HYDROXYLASE (F3'H) gene, nco in CHALCONE ISOMERASE (CHI). This work demonstrates how non-GMO approaches can transform a common crop plant into a functional food with possible health benefits.
Flavonol Biosynthesis Genes and Their Use in Engineering the Plant Antidiabetic Metabolite Montbretin A.
Irmisch Sandra,Ruebsam Henriette,Jancsik Sharon,Man Saint Yuen Macaire,Madilao Lufiani L,Bohlmann Joerg
The plant metabolite montbretin A (MbA) and its precursor mini-MbA are potential new drugs for treating type 2 diabetes. These complex acylated flavonol glycosides only occur in small amounts in the corms of the ornamental plant montbretia ( × ). Our goal is to metabolically engineer using montbretia genes to achieve increased production of mini-MbA and MbA. Two montbretia UDP-dependent glycosyltransferases (UGTs), CcUGT1 and CcUGT2, catalyze the formation of the first two pathway-specific intermediates in MbA biosynthesis, myricetin 3--rhamnoside and myricetin 3--glucosyl rhamnoside. In previous work, expression of these UGTs in resulted in small amounts of kaempferol glycosides but not myricetin glycosides, suggesting that myricetin was limiting. Here, we investigated montbretia genes and enzymes of flavonol biosynthesis to enhance myricetin formation in We characterized two flavanone hydroxylases, a flavonol synthase, a flavonoid 3'-hydroxylase (F3'H), and a flavonoid 3'5'-hydroxylase (F3'5'H). Montbretia flavonol synthase converted dihydromyricetin into myricetin. Unexpectedly, montbretia F3'5'H shared higher sequence relatedness with F3'Hs in the CYP75B subfamily of cytochromes P450 than with those with known F3'5'H activity. Transient expression of combinations of montbretia flavonol biosynthesis genes and a montbretia MYB transcription factor in resulted in availability of myricetin for MbA biosynthesis. Transient coexpression of montbretia flavonol biosynthesis genes combined with and in resulted in 2 mg g fresh weight of the MbA pathway-specific compound myricetin 3--glucosyl rhamnoside. Additional expression of the montbretia acyltransferase led to detectable levels of mini-MbA in .
The effect of drought stress on polyphenolic compounds and expression of flavonoid biosynthesis related genes in Achillea pachycephala Rech.f.
Gharibi Shima,Sayed Tabatabaei Badraldin Ebrahim,Saeidi Ghodratolah,Talebi Majid,Matkowski Adam
This study investigated the effect of drought stress on the amount of phenolic and flavonoid compounds as well as HO and malondialdehyde (MDA) in Achillea pachycephala. The expression patterns of the key genes and their molecular mechanisms in the phenylpropanoid pathway (PAL, CHS, CHI, F3H, F3'H, F3'5'H, FLS) were also assessed during drought stress using quantitative real-time polymerase chain reaction (qRT-PCR). The samples were harvested at 0, 7, 14, 21 and 28 days after exposure to drought stress. High-performance liquid chromatography (HPLC) analysis was performed to determine the changes of phenolic and flavonoid compounds - chlorogenic acid, caffeic acid, rutin, luteolin-7-O-glycoside, 1,3-dicaffeoylquinic acid, apigenin-7-O-glycoside, luteolin, apigenin and kaempferol - during stress conditions. Concentrations of most of the compounds increased with increasing drought stress duration. Most of the phenolic acids continued to accumulate with increasing duration of stress, while flavonoids dramatically decreased at day 28 of stress. Chlorogenic acid was the most abundant phenolic acid (4.97 mg/100 g dry weight [DW]) at the beginning of the experiment, while it decreased at day 7 and increased again at day 21. However, different trends were observed for some flavonoids, such as luteolin and apigenin. At the beginning of stress treatment, high accumulation of free radicals (HO) and lipid peroxidation (MDA) led to elevated expression of most of the flavonoid genes. MDA increased from 22.66 to 43.28 μmol g DW at day 28. CHS gene expression was elevated at day 7, while chi gene expression remained unchanged. At the end of the stress period, most of the flavonoid concentrations and expression of the relevant genes also increased. The results can facilitate selection of appropriate drought conditions to obtain the highest levels of flavonoids such as luteolin and apigenin and phenolic compounds such as chlorogenic acid for improved health benefits.
Genetic and environmental effects influencing fruit colour and QTL analysis in raspberry.
McCallum Susan,Woodhead Mary,Hackett Christine A,Kassim Angzzas,Paterson Alistair,Graham Julie
TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik
Raspberry (Rubus idaeus) fruit colour was assessed in the Latham x Glen Moy mapping population using a colour meter and visual scores over three seasons and three environments. The colour measurements were found to be significantly associated with pigment content, have high heritability, and stable QTL were identified across environments and seasons. Anthocyanin content has previously been shown to be the major contributor to fruit colour in red raspberry. Major structural genes (F3'H, FLS, DFR, IFR, OMT and GST) and transcription factors (bZIP, bHLH and MYB) influencing flavonoid biosynthesis have been identified, mapped and shown to underlie QTL for quantitative and qualitative anthocyanin composition. Favourable alleles for the selected traits were identified for the aspects of fruit colour and partitioning of individual pigments.
Expansion and subfunctionalisation of flavonoid 3',5'-hydroxylases in the grapevine lineage.
Falginella Luigi,Castellarin Simone D,Testolin Raffaele,Gambetta Gregory A,Morgante Michele,Di Gaspero Gabriele
BACKGROUND:Flavonoid 3',5'-hydroxylases (F3'5'Hs) and flavonoid 3'-hydroxylases (F3'Hs) competitively control the synthesis of delphinidin and cyanidin, the precursors of blue and red anthocyanins. In most plants, F3'5'H genes are present in low-copy number, but in grapevine they are highly redundant. RESULTS:The first increase in F3'5'H copy number occurred in the progenitor of the eudicot clade at the time of the γ triplication. Further proliferation of F3'5'Hs has occurred in one of the paleologous loci after the separation of Vitaceae from other eurosids, giving rise to 15 paralogues within 650 kb. Twelve reside in 9 tandem blocks of ~35-55 kb that share 91-99% identity. The second paleologous F3'5'H has been maintained as an orphan gene in grapevines, and lacks orthologues in other plants. Duplicate F3'5'Hs have spatially and temporally partitioned expression profiles in grapevine. The orphan F3'5'H copy is highly expressed in vegetative organs. More recent duplicate F3'5'Hs are predominately expressed in berry skins. They differ only slightly in the coding region, but are distinguished in the structure of the promoter. Differences in cis-regulatory sequences of promoter regions are paralleled by temporal specialisation of gene transcription during fruit ripening. Variation in anthocyanin profiles consistently reflects changes in the F3'5'H mRNA pool across different cultivars. More F3'5'H copies are expressed at high levels in grapevine varieties with 93-94% of 3'5'-OH anthocyanins. In grapevines depleted in 3'5'-OH anthocyanins (15-45%), fewer F3'5'H copies are transcribed, and at lower levels. Conversely, only two copies of the gene encoding the competing F3'H enzyme are present in the grape genome; one copy is expressed in both vegetative and reproductive organs at comparable levels among cultivars, while the other is transcriptionally silent. CONCLUSIONS:These results suggest that expansion and subfunctionalisation of F3'5'Hs have increased the complexity and diversification of the fruit colour phenotype among red grape varieties.
Differential expression of anthocyanin biosynthetic genes and anthocyanin accumulation in tartary buckwheat cultivars 'Hokkai t8' and 'Hokkai t10'.
Park Nam Il,Li Xiaohua,Suzuki Tatsuro,Kim Sun-Ju,Woo Sun-Hee,Park Cheol Ho,Park Sang Un
Journal of agricultural and food chemistry
Six genes involved in anthocyanin biosynthesis in tartary buckwheat have been cloned, namely, FtC4H, Ft4CL, FtCHI, FtF3H, FtF3'H, and FtANS, which encode cinnamate 4-hydroxylase (C4H), 4-coumarate:CoA ligase (4CL), chalcone isomerase (CHI), flavones 3-hydroxylase (F3H), flavonoid 3'-hydroxylase (F3'H), and anthocyanidin synthase (ANS), respectively. Then, these cDNAs were used, along with previously isolated clones for phenylalanine ammonia-lyase (PAL) and chalcone synthase (CHS), to compare gene expression in different organs, flowering stages, and maturing seeds of tartary buckwheat cultivars 'Hokkai T8' and 'Hokkai T10'. Quantitative real-time polymerase chain reaction analysis showed that these anthocyanin biosynthetic genes were most highly expressed in the stems and roots of Hokkai T10. The FtANS gene was more highly expressed than other genes during flowering and maturing seeds. In addition, the anthocyanin concentration was higher in 'Hokkai T10' than in 'Hokkai T8'; however, naringenin chalcone, a flavonoid, was absent from 'Hokkai T10' seedlings based on fluorescence microscopy.
Identification of the pr1 gene product completes the anthocyanin biosynthesis pathway of maize.
Sharma Mandeep,Cortes-Cruz Moises,Ahern Kevin R,McMullen Michael,Brutnell Thomas P,Chopra Surinder
In maize, mutations in the pr1 locus lead to the accumulation of pelargonidin (red) rather than cyanidin (purple) pigments in aleurone cells where the anthocyanin biosynthetic pathway is active. We characterized pr1 mutation and isolated a putative F3'H encoding gene (Zmf3'h1) and showed by segregation analysis that the red kernel phenotype is linked to this gene. Genetic mapping using SNP markers confirms its position on chromosome 5L. Furthermore, genetic complementation experiments using a CaMV 35S::ZmF3'H1 promoter-gene construct established that the encoded protein product was sufficient to perform a 3'-hydroxylation reaction. The Zmf3'h1-specific transcripts were detected in floral and vegetative tissues of Pr1 plants and were absent in pr1. Four pr1 alleles were characterized: two carry a 24 TA dinucleotide repeat insertion in the 5'-upstream promoter region, a third has a 17-bp deletion near the TATA box, and a fourth contains a Ds insertion in exon1. Genetic and transcription assays demonstrated that the pr1 gene is under the regulatory control of anthocyanin transcription factors red1 and colorless1. The cloning and characterization of pr1 completes the molecular identification of all genes encoding structural enzymes of the anthocyanin pathway of maize.
Flavonols: old compounds for old roles.
Pollastri Susanna,Tattini Massimiliano
Annals of botany
BACKGROUND:New roles for flavonoids, as developmental regulators and/or signalling molecules, have recently been proposed in eukaryotic cells exposed to a wide range of environmental stimuli. In plants, these functions are actually restricted to flavonols, the ancient and widespread class of flavonoids. In mosses and liverworts, the whole set of genes for flavonol biosynthesis - CHS, CHI, F3H, FLS and F3'H - has been detected. The flavonol branch pathway has remained intact for millions of years, and is almost exclusively involved in the responses of plants to a wide array of stressful agents, despite the fact that evolution of flavonoid metabolism has produced >10 000 structures. SCOPE:Here the emerging functional roles of flavonoids in the responses of present-day plants to different stresses are discussed based on early, authoritative views of their primary functions during the colonization of land by plants. Flavonols are not as efficient as other secondary metabolites in absorbing wavelengths in the 290-320 nm spectral region, but display the greatest potential to keep stress-induced changes in cellular reactive oxygen species homeostasis under control, and to regulate the development of individual organs and the whole plant. Very low flavonol concentrations, as probably occurred in early terrestrial plants, may fully accomplish these regulatory functions. CONCLUSIONS:During the last two decades the routine use of genomic, chromatography/mass spectrometry and fluorescence microimaging techniques has provided new insights into the regulation of flavonol metabolism as well as on the inter- and intracellular distribution of stress-responsive flavonols. These findings offer new evidence on how flavonols may have performed a wide array of functional roles during the colonization of land by plants. In our opinion this ancient flavonoid class is still playing the same old and robust roles in present-day plants.
Allelic variants from Dahlia variabilis encode flavonoid 3'-hydroxylases with functional differences in chalcone 3-hydroxylase activity.
Schlangen Karin,Miosic Silvija,Halbwirth Heidi
Archives of biochemistry and biophysics
In the petals of Dahlia variabilis, hydroxylation of chalcones at position 3 can be detected, except the well-known flavonoid 3'-hydroxylation. Although the reaction is well characterized at the enzymatic level, it remained unclear whether it is catalyzed by a flavonoid 3'-hydroxylase (F3'H, EC126.96.36.199, CYP75B) with broad substrate specificity. Two novel allelic variants of F3'H were cloned from D. variabilis, which differ only in three amino acids within their 508 residues. The corresponding recombinant enzymes show significant differences in their chalcone 3-hydroxylase (CH3H) activity. A substitution of alanine at position 425 with valine enables CH3H activity, whereas the reciprocal substitution leads to a loss of CH3H activity. Interaction of the valine at position 425 with not yet identified structural properties seems to be decisive for chalcone acceptance. This is the first identification of an F3'H which is able to catalyze chalcone 3-hydroxylation to a physiologically relevant extent from any plant species.
Isolation and characterization of GtMYBP3 and GtMYBP4, orthologues of R2R3-MYB transcription factors that regulate early flavonoid biosynthesis, in gentian flowers.
Nakatsuka Takashi,Saito Misa,Yamada Eri,Fujita Kohei,Kakizaki Yuko,Nishihara Masahiro
Journal of experimental botany
Flavonoids are one of the major plant pigments for flower colour. Not only coloured anthocyanins, but also co-pigment flavones or flavonols, accumulate in flowers. To study the regulation of early flavonoid biosynthesis, two R2R3-MYB transcription factors, GtMYBP3 and GtMYBP4, were identified from the petals of Japanese gentian (Gentiana triflora). Phylogenetic analysis showed that these two proteins belong to the subgroup 7 clade (flavonol-specific MYB), which includes Arabidopsis AtMYB12, grapevine VvMYBF1, and tomato SlMYB12. Gt MYBP3 and Gt MYBP4 transcripts were detected specifically in young petals and correlated with the profiles of flavone accumulation. Transient expression assays showed that GtMYBP3 and GtMYBP4 enhanced the promoter activities of early biosynthetic genes, including flavone synthase II (FNSII) and flavonoid 3'-hydroxylase (F3'H), but not the late biosynthetic gene, flavonoid 3',5'-hydroxylase (F3'5'H). GtMYBP3 also enhanced the promoter activity of the chalcone synthase (CHS) gene. In transgenic Arabidopsis, overexpression of Gt MYBP3 and Gt MYBP4 activated the expression of endogenous flavonol biosynthesis genes and led to increased flavonol accumulation in seedlings. In transgenic tobacco petals, overexpression of Gt MYBP3 and Gt MYBP4 caused decreased anthocyanin levels, resulting in pale flower colours. Gt MYBP4-expressing transgenic tobacco flowers also showed increased flavonols. As far as is known, this is the first functional characterization of R2R3-MYB transcription factors regulating early flavonoid biosynthesis in petals.
An active hAT transposable element causing bud mutation of carnation by insertion into the flavonoid 3'-hydroxylase gene.
Momose Masaki,Nakayama Masayoshi,Itoh Yoshio,Umemoto Naoyuki,Toguri Toshihiro,Ozeki Yoshihiro
Molecular genetics and genomics : MGG
The molecular mechanisms underlying spontaneous bud mutations, which provide an important breeding tool in carnation, are poorly understood. Here we describe a new active hAT type transposable element, designated Tdic101, the movement of which caused a bud mutation in carnation that led to a change of flower color from purple to deep pink. The color change was attributed to Tdic101 insertion into the second intron of F3'H, the gene for flavonoid 3'-hydroxylase responsible for purple pigment production. Regions on the deep pink flowers of the mutant can revert to purple, a visible phenotype of, as we show, excision of the transposable element. Sequence analysis revealed that Tdic101 has the characteristics of an autonomous element encoding a transposase. A related, but non-autonomous element dTdic102 was found to move in the genome of the bud mutant as well. Its mobilization might be the result of transposase activities provided by other elements such as Tdic101. In carnation, therefore, the movement of transposable elements plays an important role in the emergence of a bud mutation.
The Arabidopsis thaliana mutant air1 implicates SOS3 in the regulation of anthocyanins under salt stress.
Van Oosten Michael James,Sharkhuu Altanbadralt,Batelli Giorgia,Bressan Ray Anthony,Maggio Albino
Plant molecular biology
The accumulation of anthocyanins in plants exposed to salt stress has been largely documented. However, the functional link and regulatory components underlying the biosynthesis of these molecules during exposure to stress are largely unknown. In a screen of second site suppressors of the salt overly sensitive3-1 (sos3-1) mutant, we isolated the anthocyanin-impaired-response-1 (air1) mutant. air1 is unable to accumulate anthocyanins under salt stress, a key phenotype of sos3-1 under high NaCl levels (120 mM). The air1 mutant showed a defect in anthocyanin production in response to salt stress but not to other stresses such as high light, low phosphorous, high temperature or drought stress. This specificity indicated that air1 mutation did not affect anthocyanin biosynthesis but rather its regulation in response to salt stress. Analysis of this mutant revealed a T-DNA insertion at the first exon of an Arabidopsis thaliana gene encoding for a basic region-leucine zipper transcription factor. air1 mutants displayed higher survival rates compared to wild-type in oxidative stress conditions, and presented an altered expression of anthocyanin biosynthetic genes such as F3H, F3'H and LDOX in salt stress conditions. The results presented here indicate that AIR1 is involved in the regulation of various steps of the flavonoid and anthocyanin accumulation pathways and is itself regulated by the salt-stress response signalling machinery. The discovery and characterization of AIR1 opens avenues to dissect the connections between abiotic stress and accumulation of antioxidants in the form of flavonoids and anthocyanins.
Dihydroflavonol 4-reductase genes encode enzymes with contrasting substrate specificity and show divergent gene expression profiles in Fragaria species.
Miosic Silvija,Thill Jana,Milosevic Malvina,Gosch Christian,Pober Sabrina,Molitor Christian,Ejaz Shaghef,Rompel Annette,Stich Karl,Halbwirth Heidi
During fruit ripening, strawberries show distinct changes in the flavonoid classes that accumulate, switching from the formation of flavan 3-ols and flavonols in unripe fruits to the accumulation of anthocyanins in the ripe fruits. In the common garden strawberry (Fragaria×ananassa) this is accompanied by a distinct switch in the pattern of hydroxylation demonstrated by the almost exclusive accumulation of pelargonidin based pigments. In Fragaria vesca the proportion of anthocyanins showing one (pelargonidin) and two (cyanidin) hydroxyl groups within the B-ring is almost equal. We isolated two dihydroflavonol 4-reductase (DFR) cDNA clones from strawberry fruits, which show 82% sequence similarity. The encoded enzymes revealed a high variability in substrate specificity. One enzyme variant did not accept DHK (with one hydroxyl group present in the B-ring), whereas the other strongly preferred DHK as a substrate. This appears to be an uncharacterized DFR variant with novel substrate specificity. Both DFRs were expressed in the receptacle and the achenes of both Fragaria species and the DFR2 expression profile showed a pronounced dependence on fruit development, whereas DFR1 expression remained relatively stable. There were, however, significant differences in their relative rates of expression. The DFR1/DFR2 expression ratio was much higher in the Fragaria×ananassa and enzyme preparations from F.×ananassa receptacles showed higher capability to convert DHK than preparations from F. vesca. Anthocyanin concentrations in the F.×ananassa cultivar were more than twofold higher and the cyanidin:pelargonidin ratio was only 0.05 compared to 0.51 in the F. vesca cultivar. The differences in the fruit colour of the two Fragaria species can be explained by the higher expression of DFR1 in F.×ananassa as compared to F. vesca, a higher enzyme efficiency (Kcat/Km values) of DFR1 combined with the loss of F3'H activity late in fruit development of F.×ananassa.
Purple-grained barley (Hordeum vulgare L.): marker-assisted development of NILs for investigating peculiarities of the anthocyanin biosynthesis regulatory network.
Gordeeva Elena I,Glagoleva Anastasiya Yu,Kukoeva Tatjana V,Khlestkina Elena K,Shoeva Olesya Yu
BMC plant biology
BACKGROUND:Anthocyanins are plants secondary metabolites important for plant adaptation to severe environments and potentially beneficial to human health. Purple colour of barley grain is caused by the pigments synthesized in pericarp. One or two genes determine the trait. One of them is Ant2 mapped on chromosome 2HL and is known to encode transcription factor (TF) with a bHLH domain. In plants, bHLH regulates anthocyanin biosynthesis together with TF harboring an R2R3-MYB domain. In wheat, the R2R3-MYBs responsible for purple colour of grain pericarp are encoded by the homoallelic series of the Pp-1 genes that were mapped on the short arms of chromosomes 7. In barley, in orthologous positions to wheat's Pp-1, the Ant1 gene determining red colour of leaf sheath has been mapped. In the current study, we tested whether Ant1 has pleiotropic effect not only on leaf sheath colour but also on pericarp pigmentation. RESULTS:А set of near isogenic lines (NILs) carrying different combinations of alleles at the Ant1 and Ant2 loci was created using markers-assisted backcrossing approach. The dominant alleles of both the Ant1 and Ant2 genes are required for anthocyanin accumulation in pericarp. A qRT-PCR analysis of the Ant genes in lemma and pericarp of the NILs revealed that some reciprocal interaction occurs between the genes. Expression of each of the two genes was up-regulated in purple-grained line with dominant alleles at the both loci. The lines carrying dominant allele either in the Ant1 or in the Ant2 locus were characterized by the decreased level of expression of the dominant gene and scant activity of the recessive one. The Ant1 and Ant2 expression was barely detected in uncolored line with recessive alleles at both loci. The anthocyanin biosynthesis structural genes were differently regulated: Chs, Chi, F3h, Dfr were transcribed in all lines independently on allelic state of the Ant1 and Ant2 genes, whereas F3'h and Ans were activated in presence on dominant alleles of the both regulatory genes. CONCLUSIONS:The R2R3-MYB-encoding counterpart (Ant1) of the regulatory Ant2 gene was determined for the first time. The dominant alleles of both of them are required for activation of anthocyanin synthesis in barley lemma and pericarp. The R2R3-MYB + bHLH complex activates the synthesis via affecting expression of the F3'h and Ans structural genes. In addition, positive regulatory loop between Ant1 and Ant2 was detected. Earlier the interaction between the anthocyanin biosynthesis regulatory genes has been revealed in dicot plant species only. Our data demonstrated that the regulatory mechanism is considered to be more common for plant kingdom than it has been reported so far.
Sequence diversity and differential expression of major phenylpropanoid-flavonoid biosynthetic genes among three mango varieties.
Hoang Van L T,Innes David J,Shaw P Nicholas,Monteith Gregory R,Gidley Michael J,Dietzgen Ralf G
BACKGROUND:Mango fruits contain a broad spectrum of phenolic compounds which impart potential health benefits; their biosynthesis is catalysed by enzymes in the phenylpropanoid-flavonoid (PF) pathway. The aim of this study was to reveal the variability in genes involved in the PF pathway in three different mango varieties Mangifera indica L., a member of the family Anacardiaceae: Kensington Pride (KP), Irwin (IW) and Nam Doc Mai (NDM) and to determine associations with gene expression and mango flavonoid profiles. RESULTS:A close evolutionary relationship between mango genes and those from the woody species poplar of the Salicaceae family (Populus trichocarpa) and grape of the Vitaceae family (Vitis vinifera), was revealed through phylogenetic analysis of PF pathway genes. We discovered 145 SNPs in total within coding sequences with an average frequency of one SNP every 316 bp. Variety IW had the highest SNP frequency (one SNP every 258 bp) while KP and NDM had similar frequencies (one SNP every 369 bp and 360 bp, respectively). The position in the PF pathway appeared to influence the extent of genetic diversity of the encoded enzymes. The entry point enzymes phenylalanine lyase (PAL), cinnamate 4-mono-oxygenase (C4H) and chalcone synthase (CHS) had low levels of SNP diversity in their coding sequences, whereas anthocyanidin reductase (ANR) showed the highest SNP frequency followed by flavonoid 3'-hydroxylase (F3'H). Quantitative PCR revealed characteristic patterns of gene expression that differed between mango peel and flesh, and between varieties. CONCLUSIONS:The combination of mango expressed sequence tags and availability of well-established reference PF biosynthetic genes from other plant species allowed the identification of coding sequences of genes that may lead to the formation of important flavonoid compounds in mango fruits and facilitated characterisation of single nucleotide polymorphisms between varieties. We discovered an association between the extent of sequence variation and position in the pathway for up-stream genes. The high expression of PAL, C4H and CHS genes in mango peel compared to flesh is associated with high amounts of total phenolic contents in peels, which suggest that these genes have an influence on total flavonoid levels in mango fruit peel and flesh. In addition, the particularly high expression levels of ANR in KP and NDM peels compared to IW peel and the significant accumulation of its product epicatechin gallate (ECG) in those extracts reflects the rate-limiting role of ANR on ECG biosynthesis in mango.
Parallel evolution at multiple levels in the origin of hummingbird pollinated flowers in Ipomoea.
Des Marais David L,Rausher Mark D
Evolution; international journal of organic evolution
A transition in flower color accompanying a shift in pollinator guilds is a prominent and repeated adaptation in angiosperms. In many cases, shifts to similar pollinators are associated with similar flower-color transitions. The extent to which this parallelism at the phenotypic level results from parallel changes at the biochemical, developmental, and genetic levels, however, remains an open question. There have been few attempts to determine whether parallelism at these lower levels results from mutation bias or fixation bias of different classes of mutation. We address these issues by examining the biochemical, developmental, and genetic changes that have occurred in red-flowering species of the Mina lineage of morning glories (Ipomoea) and compare these to the changes reported for I. horsfalliae, which has independently evolved red flowers. Using transgenic techniques, we demonstrate that the transition from blue to red flowers in Mina species is due primarily to down-regulation of the enzyme flavonol-3'-hydroxylase (F3'H) in flowers but not in vegetative tissues, and that this down-regulation is at least partly due to cis-regulatory change in the gene for F3'H. These changes are similar to those exhibited by I. horsfalliae, indicating parallelism at the biochemical and developmental levels, and possibly at the genetic level.
Identification of candidate flavonoid pathway genes using transcriptome correlation network analysis in ripe strawberry (Fragaria × ananassa) fruits.
Pillet Jeremy,Yu Hao-Wei,Chambers Alan H,Whitaker Vance M,Folta Kevin M
Journal of experimental botany
New modulators of the strawberry flavonoid pathway were identified through correlation network analysis. The transcriptomes of red, ripe fruit from two parental lines and 14 of their progeny were compared, and uncharacterized transcripts matching the expression patterns of known flavonoid-pathway genes were identified. Fifteen transcripts corresponded with putative transcription factors, and several of these were examined experimentally using transient expression in developing fruits. The results suggest that two of the newly-identified regulators likely contribute to discrete nodes of the flavonoid pathway. One increases only LEUCOANTHOCYANIDIN REDUCTASE (LAR) and FLAVONOL 3'-HYDROXYLASE (F3'H) transcript accumulation upon overexpression. Another affects LAR and FLAVONOL SYNTHASE (FLS) after overexpression. The third putative transcription factor appears to be a universal regulator of flavonoid-pathway genes, as many pathway transcripts decrease in abundance when this gene is silenced. This report demonstrates that such systems-level approaches may be especially powerful when connected to an effective transient expression system, helping to provide rapid and strong evidence of gene function in key fruit-ripening processes.
Metabolite profiling and expression analysis of flavonoid, vitamin C and tocopherol biosynthesis genes in the antioxidant-rich sea buckthorn (Hippophae rhamnoides L.).
Fatima Tahira,Kesari Vigya,Watt Ian,Wishart David,Todd James F,Schroeder William R,Paliyath Gopinadhan,Krishna Priti
In this study, phenolic compounds were analyzed in developing berries of four Canadian grown sea buckthorn (Hippophae rhamnoides L.) cultivars ('RC-4', 'E6590', 'Chuyskaya' and 'Golden Rain') and in leaves of two of these cultivars. Among phenolic acids, p-coumaric acid was the highest in berries, while gallic acid was predominant in leaves. In the flavonoid class of compounds, myricetin/rutin, kaempferol, quercetin and isorhamnetin were detected in berries and leaves. Berries of the 'RC-4' cultivar had approximately ⩾ 2-fold higher levels of myricetin and quercetin at 17.5mg and 17.2 mg/100 g FW, respectively, than the other cultivars. The flavonoid content in leaves was considerably more than in berries with rutin and quercetin levels up to 135 mg and 105 mg/100 g FW, respectively. Orthologs of 15 flavonoid biosynthesis pathway genes were identified within the transcriptome of sea buckthorn mature seeds. Semi-quantitative RT-PCR analysis of these genes in developing berries indicated relatively higher expression of genes such as CHS, F3'H, DFR and LDOX in the 'RC-4' cultivar than in the 'Chuyskaya' cultivar. Vitamin C levels in ripened berries of the Canadian cultivars were on the high end of the concentration range reported for most other sea buckthorn cultivars. Orthologs of genes involved in vitamins C and E biosynthesis were also identified, expanding the genomic resources for this nutritionally important plant.
Temporal biosynthesis of flavone constituents in flax growth stages.
Zuk Magdalena,Szperlik Jakub,Hnitecka Agata,Szopa Jan
Plant physiology and biochemistry : PPB
Previous studies showed that chalcone synthase (chs) silencing in flax (Linum usitatisimum) induces a signal transduction cascade that leads to extensive modification of plant metabolism. Result presented in the current study, performed on field grown flax plants - (across the whole vegetation period) demonstrates that, in addition to its role in tannin and lignin biosynthesis, the chs gene also participates in the regulation of flavone biosynthesis during plant growth. Apigenin and luteolin glycosides constitute the flavones, the major group of flavonoids in flax. Alterations in their levels correlate with plant growth, peaking at the flower initiation stage. Suppression of chs gene expression causes significant changes in the ratio of flavone constituents at the early stage of flax growth. A significant correlation between flavonoid 3'-hydroxylase (F3'H) gene expression and accumulation of luteolin glycosides has been found, indicating that flavone biosynthesis during flax growth and development is regulated by temporal expression of this gene. The lack of such a correlation between the flavone synthase (FNS) gene and flavone accumulation in the course of plant growth suggests that the main route of flavone biosynthesis is mediated by eriodictyol. This is the first report indicating the ratio of flavone constituents as a potent marker of flax growth stages and temporal expression of F3'H, the key gene of their biosynthesis.
Berry skin development in Norton grape: distinct patterns of transcriptional regulation and flavonoid biosynthesis.
Ali Mohammad B,Howard Susanne,Chen Shangwu,Wang Yechun,Yu Oliver,Kovacs Laszlo G,Qiu Wenping
BMC plant biology
BACKGROUND:The complex and dynamic changes during grape berry development have been studied in Vitis vinifera, but little is known about these processes in other Vitis species. The grape variety 'Norton', with a major portion of its genome derived from Vitis aestivalis, maintains high levels of malic acid and phenolic acids in the ripening berries in comparison with V. vinifera varieties such as Cabernet Sauvignon. Furthermore, Norton berries develop a remarkably high level of resistance to most fungal pathogens while Cabernet Sauvignon berries remain susceptible to those pathogens. The distinct characteristics of Norton and Cabernet Sauvignon merit a comprehensive analysis of transcriptional regulation and metabolite pathways. RESULTS:A microarray study was conducted on transcriptome changes of Norton berry skin during the period of 37 to 127 days after bloom, which represents berry developmental phases from herbaceous growth to full ripeness. Samples of six berry developmental stages were collected. Analysis of the microarray data revealed that a total of 3,352 probe sets exhibited significant differences at transcript levels, with two-fold changes between at least two developmental stages. Expression profiles of defense-related genes showed a dynamic modulation of nucleotide-binding site-leucine-rich repeat (NBS-LRR) resistance genes and pathogenesis-related (PR) genes during berry development. Transcript levels of PR-1 in Norton berry skin clearly increased during the ripening phase. As in other grapevines, genes of the phenylpropanoid pathway were up-regulated in Norton as the berry developed. The most noticeable was the steady increase of transcript levels of stilbene synthase genes. Transcriptional patterns of six MYB transcription factors and eleven structural genes of the flavonoid pathway and profiles of anthocyanins and proanthocyanidins (PAs) during berry skin development were analyzed comparatively in Norton and Cabernet Sauvignon. Transcriptional patterns of MYB5A and MYB5B were similar during berry development between the two varieties, but those of MYBPA1 and MYBPA2 were strikingly different, demonstrating that the general flavonoid pathways are regulated under different MYB factors. The data showed that there were higher transcript levels of the genes encoding flavonoid-3'-O-hydroxylase (F3'H), flavonoid-3',5'-hydroxylase (F3'5'H), leucoanthocyanidin dioxygenase (LDOX), UDP-glucose:flavonoid 3'-O-glucosyltransferase (UFGT), anthocyanidin reductase (ANR), leucoanthocyanidin reductase (LAR) 1 and LAR2 in berry skin of Norton than in those of Cabernet Sauvignon. It was also found that the total amount of anthocyanins was markedly higher in Norton than in Cabernet Sauvignon berry skin at harvest, and five anthocyanin derivatives and three PA compounds exhibited distinctive accumulation patterns in Norton berry skin. CONCLUSIONS:This study provides an overview of the transcriptome changes and the flavonoid profiles in the berry skin of Norton, an important North American wine grape, during berry development. The steady increase of transcripts of PR-1 and stilbene synthase genes likely contributes to the developmentally regulated resistance during ripening of Norton berries. More studies are required to address the precise role of each stilbene synthase gene in berry development and disease resistance. Transcriptional regulation of MYBA1, MYBA2, MYB5A and MYBPA1 as well as expression levels of their putative targets F3'H, F3'5'H, LDOX, UFGT, ANR, LAR1, and LAR2 are highly correlated with the characteristic anthocyanin and PA profiles in Norton berry skin. These results reveal a unique pattern of the regulation of transcription and biosynthesis pathways underlying the viticultural and enological characteristics of Norton grape, and yield new insights into the understanding of the flavonoid pathway in non-vinifera grape varieties.
Biotransformation of naringenin to eriodictyol by Saccharomyces cerevisiea functionally expressing flavonoid 3' hydroxylase.
Amor Ilef Limem-Ben,Hehn Alain,Guedone Emmanuel,Ghedira Kamel,Engasser Jean-Marc,Chekir-Ghedrira Leila,Ghoul Mohamed
Natural product communications
To increase the biological activities of flavonoids and to enhance their stability and solubility by functionalization reactions (polymerization, esterification, alkylation, glycosylation and acylation), an increase in the number of hydroxyl groups in these molecules is needed. Hydroxylation reactions may be achieved using either chemical or enzymatic methods, the latter being more highly specific than the former. In our study, the flavonoid 3' hydroxylase (F3'H) from Gerbera hybrid, functionally expressed in Saccharomyces cerevisiae, was used to hydroxylate naringenin (the first flavonoid core synthesized in plants). Furthermore, we studied factors that may affect naringenin hydroxylation by recombinant cell-like yeast growth on selective or rich media and plasmid stability. The whole recombinant cells hydroxylated naringenin at position 3' to give eriodictyol. In a selective media, the yeast failed to grow to high cell densities (maximum 5 g/L), but the plasmid stability was nearly 90%, and naringenin hydroxylation reached 100%. In a rich complex media, the biomass reached 10 g/L, but the yield of naringenin hydroxylation reached only 71%, and the plasmid stability decreased. When yeast functionally expressing F3'H from Gerbera hybrid was used, in a selective media, 200 mg/L of eriodictyol from naringenin was produced.
A chimeric repressor of petunia PH4 R2R3-MYB family transcription factor generates margined flowers in torenia.
Kasajima Ichiro,Sasaki Katsutomo
Plant signaling & behavior
The development of new phenotypes is key to the commercial development of the main floricultural species and cultivars. Important new phenotypes include features such as multiple-flowers, color variations, increased flower size, new petal shapes, variegation and distinctive petal margin colourations. Although their commercial use is not yet common, the transgenic technologies provide a potentially rapid means of generating interesting new phenotypes. In this report, we construct 5 vectors which we expected to change the color of the flower anthocyanins, from purple to blue, regulating vacuolar pH. When these constructs were transformed into purple torenia, we unexpectedly recovered some genotypes having slightly margined petals. These transgenic lines expressed a chimeric repressor of the petunia PhPH4 gene under the control of Cauliflower mosaic virus 35 S RNA promoter. PhPH4 is an R2R3-type MYB transcription factor. The transgenic lines lacked pigmentation in the petal margin cells both on the adaxial and abaxial surfaces. Expressions of Flavanone 3-hydroxylase (F3H), Flavonoid 3'-hydroxylase (F3'H) and Flavonoid 3'5'-hydroxylase (F3'5'H) genes were reduced in the margins of these transgenic lines, suggesting an inhibitory effect of PhPH4 repressor on anthocyanin synthesis.
Regulation of the Flavonoid Biosynthesis Pathway Genes in Purple and Black Grains of Hordeum vulgare.
Shoeva Olesya Yu,Mock Hans-Peter,Kukoeva Tatjana V,Börner Andreas,Khlestkina Elena K
Barley grain at maturity can have yellow, purple, blue, and black pigmentations which are suggested to play a protective role under stress conditions. The first three types of the colors are caused by phenolic compounds flavonoids; the last one is caused by phytomelanins, oxidized and polymerized phenolic compounds. Although the genetic basis of the flavonoid biosynthesis pathway in barley has been thoroughly studied, there is no data yet on its regulation in purple and black barley grains. In the current study, genetic model of Hordeum vulgare 'Bowman' near-isogenic lines (NILs) was used to investigate the regulation of the flavonoid biosynthesis in white, purple, and black barley grains. Microsatellite genotyping revealed donor segments in the purple- and black-grained lines on chromosomes 2H (in region of the Ant2 gene determining purple color of grains) and 1H (in region of the Blp gene determining black lemma and pericarp), respectively. The isolated dominant Ant2 allele of the purple-grained line has high level of sequence similarity with the recessive Bowman's ant2 in coding region, whereas an insertion of 179 bp was detected in promoter region of ant2. This structural divergence between Ant2 and ant2 alleles may underlie their different expression in grain pericarp: Bowman's Ant2 is not transcribed, whereas it was up-regulated in the purple-grained line with coordinately co-expressed flavonoid biosynthesis structural genes (Chs, Chi, F3h, F3'h, Dfr, Ans). This led to total anthocyain content increase in purple-grained line identified by ultra-performance liquid chromatography (HPLC). Collectively, these results proved the regulatory function of the Ant2 gene in anthocyanin biosynthesis in barley grain pericarp. In the black-grained line, the specific transcriptional regulation of the flavonoid biosynthesis pathway genes was not detected, suggesting that flavonoid pigments are not involved in development of black lemma and pericarp trait.
Genome-Wide Association Analysis of the Anthocyanin and Carotenoid Contents of Rose Petals.
Schulz Dietmar F,Schott Rena T,Voorrips Roeland E,Smulders Marinus J M,Linde Marcus,Debener Thomas
Frontiers in plant science
Petal color is one of the key characteristics determining the attractiveness and therefore the commercial value of an ornamental crop. Here, we present the first genome-wide association study for the important ornamental crop rose, focusing on the anthocyanin and carotenoid contents in petals of 96 diverse tetraploid garden rose genotypes. Cultivated roses display a vast phenotypic and genetic diversity and are therefore ideal targets for association genetics. For marker analysis, we used a recently designed Axiom SNP chip comprising 68,000 SNPs with additionally 281 SSRs, 400 AFLPs and 246 markers from candidate genes. An analysis of the structure of the rose population revealed three subpopulations with most of the genetic variation between individual genotypes rather than between clusters and with a high average proportion of heterozygous loci. The mapping of markers significantly associated with anthocyanin and carotenoid content to the related and genomes revealed clusters of associated markers indicating five genomic regions associated with the total anthocyanin content and two large clusters associated with the carotenoid content. Among the marker clusters associated with the phenotypes, we found several candidate genes with known functions in either the anthocyanin or the carotenoid biosynthesis pathways. Among others, we identified a glutathione-S-transferase, 4CL, an auxin response factor and F3'H as candidate genes affecting anthocyanin concentration, and CCD4 and Zeaxanthine epoxidase as candidates affecting the concentration of carotenoids. These markers are starting points for future validation experiments in independent populations as well as for functional genomic studies to identify the causal factors for the observed color phenotypes. Furthermore, validated markers may be interesting tools for marker-assisted selection in commercial breeding programmes in that they provide the tools to identify superior parental combinations that combine several associated markers in higher dosages.
Comparative Transcriptome Analysis of Chinary, Assamica and Cambod tea (Camellia sinensis) Types during Development and Seasonal Variation using RNA-seq Technology.
Kumar Ajay,Chawla Vandna,Sharma Eshita,Mahajan Pallavi,Shankar Ravi,Yadav Sudesh Kumar
Tea quality and yield is influenced by various factors including developmental tissue, seasonal variation and cultivar type. Here, the molecular basis of these factors was investigated in three tea cultivars namely, Him Sphurti (H), TV23 (T), and UPASI-9 (U) using RNA-seq. Seasonal variation in these cultivars was studied during active (A), mid-dormant (MD), dormant (D) and mid-active (MA) stages in two developmental tissues viz. young and old leaf. Development appears to affect gene expression more than the seasonal variation and cultivar types. Further, detailed transcript and metabolite profiling has identified genes such as F3'H, F3'5'H, FLS, DFR, LAR, ANR and ANS of catechin biosynthesis, while MXMT, SAMS, TCS and XDH of caffeine biosynthesis/catabolism as key regulators during development and seasonal variation among three different tea cultivars. In addition, expression analysis of genes related to phytohormones such as ABA, GA, ethylene and auxin has suggested their role in developmental tissues during seasonal variation in tea cultivars. Moreover, differential expression of genes involved in histone and DNA modification further suggests role of epigenetic mechanism in coordinating global gene expression during developmental and seasonal variation in tea. Our findings provide insights into global transcriptional reprogramming associated with development and seasonal variation in tea.
Overexpression of PaNAC03, a stress induced NAC gene family transcription factor in Norway spruce leads to reduced flavonol biosynthesis and aberrant embryo development.
Dalman Kerstin,Wind Julia Johanna,Nemesio-Gorriz Miguel,Hammerbacher Almuth,Lundén Karl,Ezcurra Ines,Elfstrand Malin
BMC plant biology
BACKGROUND:The NAC family of transcription factors is one of the largest gene families of transcription factors in plants and the conifer NAC gene family is at least as large, or possibly larger, as in Arabidopsis. These transcription factors control both developmental and stress induced processes in plants. Yet, conifer NACs controlling stress induced processes has received relatively little attention. This study investigates NAC family transcription factors involved in the responses to the pathogen Heterobasidion annosum (Fr.) Bref. sensu lato. RESULTS:The phylogeny and domain structure in the NAC proteins can be used to organize functional specificities, several well characterized stress-related NAC proteins are found in III-3 in Arabidopsis (Jensen et al. Biochem J 426:183-196, 2010). The Norway spruce genome contain seven genes with similarity to subgroup III-3 NACs. Based on the expression pattern PaNAC03 was selected for detailed analyses. Norway spruce lines overexpressing PaNAC03 exhibited aberrant embryo development in response to maturation initiation and 482 misregulated genes were identified in proliferating cultures. Three key genes in the flavonoid biosynthesis pathway: a CHS, a F3'H and PaLAR3 were consistently down regulated in the overexpression lines. In accordance, the overexpression lines showed reduced levels of specific flavonoids, suggesting that PaNAC03 act as a repressor of this pathway, possibly by directly interacting with the promoter of the repressed genes. However, transactivation studies of PaNAC03 and PaLAR3 in Nicotiana benthamiana showed that PaNAC03 activated PaLAR3A, suggesting that PaNAC03 does not act as an independent negative regulator of flavan-3-ol production through direct interaction with the target flavonoid biosynthetic genes. CONCLUSIONS:PaNAC03 and its orthologs form a sister group to well characterized stress-related angiosperm NAC genes and at least PaNAC03 is responsive to biotic stress and appear to act in the control of defence associated secondary metabolite production.
Organ-specific transcriptome profiling of metabolic and pigment biosynthesis pathways in the floral ornamental progenitor species Anthurium amnicola Dressler.
Suzuki Jon Y,Amore Teresita D,Calla Bernarda,Palmer Nathan A,Scully Erin D,Sattler Scott E,Sarath Gautam,Lichty Joanne S,Myers Roxana Y,Keith Lisa M,Matsumoto Tracie K,Geib Scott M
Anthurium amnicola Dressler possesses a number of desirable and novel ornamental traits such as a purple-colored upright spathe, profuse flowering, and floral scent, some of which have been introgressed into modern Anthurium cultivars. As a first step in identifying genes associated with these traits, the transcriptome from root, leaf, spathe, and spadix from an accession of A. amnicola was assembled, resulting in 28,019 putative transcripts representing 19,458 unigenes. Genes involved in pigmentation, including those for the metabolism of chlorophyll and the biosynthesis of carotenoids, phenylpropanoids, and flavonoids were identified. The expression levels of one MYB transcription factor was highly correlated with naringenin 3-dioxygenase (F3H) and dihydroflavonol-4-reductase (DFR) in leaves, whereas a bHLH transcription factor was highly correlated with flavonoid 3'-monooxygenase (F3'H) and a DFR in spathes, suggesting that these two transcription factors might regulate flavonoid and anthocyanin synthesis in A. amnicola. Gene sequence and expression data from four major organs of A. amnicola provide novel basal information for understanding the genetic bases of ornamental traits and the determinants and evolution of form and function in the Araceae.
Insight into the role of anthocyanin biosynthesis-related genes in Medicago truncatula mutants impaired in pigmentation in leaves.
Carletti Giorgia,Lucini Luigi,Busconi Matteo,Marocco Adriano,Bernardi Jamila
Plant physiology and biochemistry : PPB
Flavonoids are the most common antioxidant compounds produced in plants. In this study, two wild types and two independent mutants of Medicago truncatula with altered anthocyanin content in leaves were characterized at the phenotype, metabolite profile, gene structure and transcript levels. Flavonoid profiles showed conserved levels of dihydroflavonols, leucoanthocyanidins and flavonols, while anthocyanidin, anthocyanin and isoflavone levels were lower in the mutants (up to 90% less) compared with the wild types. Genes encoding key enzymes of the anthocyanin pathway and transcriptional factors were analyzed by RT-PCR. Genes involved in the later steps of the anthocyanin pathway (dihydrokaempferol reductase 2, UDP-glucose:anthocyanin 3-O-glucosyltransferase and glutathione S-transferase) were found under-expressed in both mutants. Dihydrokaempferol reductase 1 was downregulated two-fold in the anthocyanin-less mutant while the UDP-glucose:anthocyanin 5-O-glucosyltransferase was strongly repressed only in the mutant with low pigmentation, suggesting a different regulation in the two genotypes. The common feature was that the first enzymes of the flavonoid biosynthesis pathway were not altered in rate of expression. A very high reduction in transcript accumulation was also found for two homologous R2R3 MYB genes, namely MtMYBA and AN2, suggesting that these genes have a role in anthocyanin accumulation in leaves. More evidence was found on analyzing their nucleotide sequence: several SNPs, insertions and deletions in the coding and non-coding regions of both MYB genes were found between mutants and wild types that could influence anthocyanin biosynthesis. Moreover, a subfamily of eight MYB genes with a high homology to MtMYBA was discovered in tandem on chromosome 5 of M. truncatula.
Iron deficiency stimulates anthocyanin accumulation in grapevine apical leaves.
Caramanico Leila,Rustioni Laura,De Lorenzis Gabriella
Plant physiology and biochemistry : PPB
Iron chlorosis is a diffuse disorder affecting Mediterranean vineyards. Beside the commonly described symptom of chlorophyll decrease, an apex reddening was recently observed. Secondary metabolites, such as anthocyanins, are often synthetized to cope with stresses in plants. The present work aimed to evaluate grapevine responses to iron deficiency, in terms of anthocyanin metabolism (reflectance spectrum, total anthocyanin content, HPLC profile and gene expression) in apical leaves of Cabernet sauvignon and Sangiovese grown in hydroponic conditions. Iron supply interruption produced after one month an increasing of anthocyanin content associated to a more stable profile in both cultivars. In Cabernet sauvignon, the higher red pigment accumulation was associated to a lower intensity of chlorotic symptoms, while in Sangiovese, despite the activation of the metabolism, the lower anthocyanin accumulation was associated to a stronger decrease in chlorophyll concentration. Gene expression data showed a significant increase of anthocyanin biosynthesis. The effects on the expression of structural and transcription factor genes of phenylpropanoid pathway were cultivar dependent. F3H, F3'H, F3'5'H and LDOX genes, in Cabernet sauvignon, and AOMT1 and AOMT genes, in Sangiovese, were positively affected by the treatment in response to iron deficiency. All data support the hypothesis of an anthocyanin biosynthesis stimulation rather than a decreased degradation of them due to iron chlorosis.
The factors affecting the evolution of the anthocyanin biosynthesis pathway genes in monocot and dicot plant species.
Shoeva Olesya Yu,Glagoleva Anastasiya Yu,Khlestkina Elena K
BMC plant biology
BACKGROUND:The available data demonstrate that even in universal metabolic pathways, some species-specific regulatory features of structural genes are present. For instance, in the anthocyanin biosynthesis pathway (ABP), genes may be regulated by ABP-specific regulatory factors, and their expression levels may be strongly associated with anthocyanin pigmentation, or they may be expressed independently of pigmentation. A dataset of orthologous ABP genes (Chs, Chi, F3h, F3'h, Dfr, Ans) from monocot and dicot plant species that have distinct gene regulation patterns and different types of pollination was constructed to test whether these factors affect the evolution of the genes. RESULTS:Using a maximum likelihood approach, we demonstrated that although the whole set of the ABP genes is under purifying selection, with greater selection acting on the upstream genes than on the downstream genes, genes from distinct groups of plant species experienced different strengths of selective pressure. The selective pressure on the genes was higher in dicots than in monocots (F3h and further downstream genes) and in pollinator-dependent plants than in pollinator-independent species (Chi and further downstream genes), suggesting an important role of pollination type in the evolution of the anthocyanin biosynthesis gene network. Contrasting effects of the regulation patterns on evolution were detected for the F3h and Dfr genes, with greater selective pressure on the F3h gene in plant species where the gene expression was not strongly associated with pigmentation and greater selective pressure on Dfr in plant species where the gene expression was associated with pigmentation. CONCLUSIONS:We demonstrated the effects of pollination type and patterns of regulation on the evolution of the ABP genes, but the evolution of some of the genes could not be explained in the framework of these factors, such as the weaker selective pressure acting on Chs in species that attract pollinators or the stronger selective pressure on F3h in plant species where the gene expression was not associated with pigmentation. The observations suggest that additional factors could affect the evolution of these genes. One such factor could be an effect of gene duplication with further division of functions among gene copies and relaxed selective pressure acting on them. Additional tests with an appropriate dataset combining data on duplicated gene sequences and their functions in the flavonoid biosynthesis pathway are required to test this hypothesis.
Convergent Evolution at the Pathway Level: Predictable Regulatory Changes during Flower Color Transitions.
Larter Maximilian,Dunbar-Wallis Amy,Berardi Andrea E,Smith Stacey D
Molecular biology and evolution
The predictability of evolution, or whether lineages repeatedly follow the same evolutionary trajectories during phenotypic convergence remains an open question of evolutionary biology. In this study, we investigate evolutionary convergence at the biochemical pathway level and test the predictability of evolution using floral anthocyanin pigmentation, a trait with a well-understood genetic and regulatory basis. We reconstructed the evolution of floral anthocyanin content across 28 species of the Andean clade Iochrominae (Solanaceae) and investigated how shifts in pigmentation are related to changes in expression of seven key anthocyanin pathway genes. We used phylogenetic multivariate analysis of gene expression to test for phenotypic and developmental convergence at a macroevolutionary scale. Our results show that the four independent losses of the ancestral pigment delphinidin involved convergent losses of expression of the three late pathway genes (F3'5'h, Dfr, and Ans). Transitions between pigment types affecting floral hue (e.g., blue to red) involve changes to the expression of branching genes F3'h and F3'5'h, while the expression levels of early steps of the pathway are strongly conserved in all species. These patterns support the idea that the macroevolution of floral pigmentation follows predictable evolutionary trajectories to reach convergent phenotype space, repeatedly involving regulatory changes. This is likely driven by constraints at the pathway level, such as pleiotropy and regulatory structure.
How to perform RT-qPCR accurately in plant species? A case study on flower colour gene expression in an azalea (Rhododendron simsii hybrids) mapping population.
De Keyser Ellen,Desmet Laurence,Van Bockstaele Erik,De Riek Jan
BMC molecular biology
BACKGROUND:Flower colour variation is one of the most crucial selection criteria in the breeding of a flowering pot plant, as is also the case for azalea (Rhododendron simsii hybrids). Flavonoid biosynthesis was studied intensively in several species. In azalea, flower colour can be described by means of a 3-gene model. However, this model does not clarify pink-coloration. The last decade gene expression studies have been implemented widely for studying flower colour. However, the methods used were often only semi-quantitative or quantification was not done according to the MIQE-guidelines. We aimed to develop an accurate protocol for RT-qPCR and to validate the protocol to study flower colour in an azalea mapping population. RESULTS:An accurate RT-qPCR protocol had to be established. RNA quality was evaluated in a combined approach by means of different techniques e.g. SPUD-assay and Experion-analysis. We demonstrated the importance of testing noRT-samples for all genes under study to detect contaminating DNA. In spite of the limited sequence information available, we prepared a set of 11 reference genes which was validated in flower petals; a combination of three reference genes was most optimal. Finally we also used plasmids for the construction of standard curves. This allowed us to calculate gene-specific PCR efficiencies for every gene to assure an accurate quantification. The validity of the protocol was demonstrated by means of the study of six genes of the flavonoid biosynthesis pathway. No correlations were found between flower colour and the individual expression profiles. However, the combination of early pathway genes (CHS, F3H, F3'H and FLS) is clearly related to co-pigmentation with flavonols. The late pathway genes DFR and ANS are to a minor extent involved in differentiating between coloured and white flowers. Concerning pink coloration, we could demonstrate that the lower intensity in this type of flowers is correlated to the expression of F3'H. CONCLUSIONS:Currently in plant research, validated and qualitative RT-qPCR protocols are still rare. The protocol in this study can be implemented on all plant species to assure accurate quantification of gene expression. We have been able to correlate flower colour to the combined regulation of structural genes, both in the early and late branch of the pathway. This allowed us to differentiate between flower colours in a broader genetic background as was done so far in flower colour studies. These data will now be used for eQTL mapping to comprehend even more the regulation of this pathway.
Violet/blue chrysanthemums--metabolic engineering of the anthocyanin biosynthetic pathway results in novel petal colors.
Brugliera Filippa,Tao Guo-Qing,Tems Ursula,Kalc Gianna,Mouradova Ekaterina,Price Kym,Stevenson Kim,Nakamura Noriko,Stacey Iolanda,Katsumoto Yukihisa,Tanaka Yoshikazu,Mason John G
Plant & cell physiology
Chrysanthemums (Chrysanthemum×morifolium Ramat.) are an important cut-flower and potted plant crop in the horticultural industry world wide. Chrysanthemums express the flavonoid 3'-hydroxylase (F3'H) gene and thus accumulate anthocyanins derived from cyanidin in their inflorescences which appear pink/red. Delphinidin-based anthocyanins are lacking due to the deficiency of a flavonoid 3', 5'-hydroxylase (F3'5'H), and so violet/blue chrysanthemum flower colors are not found. In this study, together with optimization of transgene expression and selection of the host cultivars and gene source, F3'5'H genes have been successfully utilized to produce transgenic bluish chrysanthemums that accumulate delphinidin-based anthocyanins. HPLC analysis and feeding experiments with a delphinidin precursor identified 16 cultivars of chrysanthemums out of 75 that were predicted to turn bluish upon delphinidin accumulation. A selection of eight cultivars were successfully transformed with F3'5'H genes under the control of different promoters. A pansy F3'5'H gene under the control of a chalcone synthase promoter fragment from rose resulted in the effective diversion of the anthocyanin pathway to produce delphinidin in transgenic chrysanthemum flower petals. The resultant petal color was bluish, with 40% of total anthocyanidins attributed to delphinidin. Increased delphinidin levels (up to 80%) were further achieved by hairpin RNA interference-mediated silencing of the endogenous F3'H gene. The resulting petal colors were novel bluish hues, not possible by hybridization breeding. This is the first report of the production of anthocyanins derived from delphinidin in chrysanthemum petals leading to novel flower color.
A phylogenetic examination of the primary anthocyanin production pathway of the Plantae.
Campanella James J,Smalley John V,Dempsey Maureen E
BACKGROUND:Anthocyanin pigments aid in reproduction and provide ultraviolet protection to land plants. We have examined the phylogenetic relationships among the five primary enzymes responsible for producing anthocyanin pigment in its three major forms. Dihydroflavonol 4-reductase (DFR), anthocyanidin synthase (ANS), Flavonoid 3'glucosyltransferase (F3GT), flavonoid 3'hydroxylase (F3'H), and flavonoid 3'5' hydroxylase (F3'5'H) are responsible for the final steps in anthocyanin pigment production. RESULTS:We were interested in how conserved the anthocyanin pathway genes may be among land plants, and evolutionarily how far back into the plant lineage anthocyanin production may be traced. The DFR, ANS, F3GT, and F3'H genes date back 450 million years to the first land plants. Mosses, spike mosses, and ferns express these four products, although there is no evidence of sequence orthologues for these genes in algae. Additionally, F3'5'H is not evident in organisms that predated gymnosperms. CONCLUSION:Our findings support the hypothesis that "blue" anthocyanin pigments did not evolve until 300-350 mya along with the gymnosperms, although the "red" anthocyanin pigments may be as ancient as the mosses (~450 mya).
Ultraviolet-B radiation and water deficit interact to alter flavonol and anthocyanin profiles in grapevine berries through transcriptomic regulation.
Martínez-Lüscher Johann,Sánchez-Díaz Manuel,Delrot Serge,Aguirreolea Jone,Pascual Inmaculada,Gomès Eric
Plant & cell physiology
UV-B radiation and water deficit may trigger flavonol and anthocyanin biosynthesis in plant tissues. In addition, previous research has showed strong qualitative effects on grape berry skin flavonol and anthocyanin profiles in response to UV-B and water deficit. The aim of this study is to identify the mechanisms leading to quantitative and qualitative changes in flavonol and anthocyanin profiles, in response to separate and combined UV-B and water deficit. Grapevines (Vitis vinifera L. cv. Tempranillo) were exposed to three levels of UV-B radiation (0, 5.98 and 9.66 kJ m(-2) day(-1)) and subjected to two water regimes. A strong effect of UV-B on flavonol and anthocyanin biosynthesis was found, resulting in an increased anthocyanin concentration and a change in their profile. Concomitantly, two key biosynthetic genes (FLS1 and UFGT) were up-regulated by UV-B, leading to increased flavonol and anthocyanin skin concentration. Changes in flavonol and anthocyanin composition were explained to a large extend by transcript levels of F3'H, F3'5'H and OMT2. A significant interaction between UV-B and water deficit was found in the relative abundance of 3'4' and 3'4'5' substituted flavonols, but not in their anthocyanin homologues. The ratio between 3'4'5' and 3'4' substituted flavonols was linearly related to the ratios of F3'5'H and FLS1 transcription, two steps up-regulated independently by water deficit and UV-B radiation, respectively. Our results indicate that changes in flavonol profiles in response to environmental conditions are not only a consequence of changes in the expression of flavonoid hydroxylases; but also the result of the competition of FLS, F3'5'H and F3'H enzymes for the same flavonol substrates.
Flavonoids and their qualitative variation in Calystegia soldanella and related species (Convolvulaceae).
Murai Yoshinori,Setoguchi Hiroaki,Ono Eiichiro,Iwashina Tsukasa
Natural product communications
Coastal species are exposed to severe environmental stresses, e.g. salt and UV-B. The plants adapt themselves to such harsh environment by controlling morphological features and chemical defense systems. Flavonoids are known as efficient anti-stress polyphenols produced by plants. Most flavonoids show antioxidant activity, and their properties are important for plants to survive under high-stress conditions such as those in a coastal area. Among the compounds, ortho-dihydroxylated flavonoids act as strong antioxidants. In this survey, we elucidated the flavonoid composition of a seashore species Calystegia soldanella, which is distributed not only on the seashore, but also by the inland freshwater lake, Lake Biwa. Seven flavonol glycosides, i.e. quercetin 3-0- rutinoside, 3-O-glucoside, 3-O-rhamnoside and 3-O-apiosyl-(1-->2)-[rhamnosyl-(1-->6)-glucoside], and kaempferol 3-O-rutinoside, 3-O-glucoside and 3-0- rhamnoside were isolated from the leaves of C. soldanella. In addition, it was shown that the quercetin (Qu) to kaempferol (Km) ratio of coastal populations was higher than that of lakeshore populations. In general, these differences of Qu/Km ratio depend on flavonoid 3'-hydroxylase (F3'H) transcription. RT-PCR analysis suggested that F3'H of C. soldanella is regulated translationally or post-translationally, but not transcriptionally. Furthermore, quantitative and qualitative differences in flavonoid composition occurred among three Calystegia species, C. soldanella, C. japonica and C. hederacea.
Expression of the sweetpotato R2R3-type IbMYB1a gene induces anthocyanin accumulation in Arabidopsis.
Chu Hyosub,Jeong Jae Cheol,Kim Wook-Jin,Chung Dong Min,Jeon Hyo Kon,Ahn Young Ock,Kim Sun Ha,Lee Haeng-Soon,Kwak Sang-Soo,Kim Cha Young
R2R3-type MYB transcription factors (TFs) play important roles in transcriptional regulation of anthocyanins. The R2R3-type IbMYB1 is known to be a key regulator of anthocyanin biosynthesis in the storage roots of sweetpotato. We previously showed that transient expression of IbMYB1a led to anthocyanin pigmentation in tobacco leaves. In this article, we generated transgenic Arabidopsis plants expressing the IbMYB1a gene under the control of CaMV 35S promoter, and the sweetpotato SPO and SWPA2 promoters. Overexpression of IbMYBa in transgenic Arabidopsis produced strong anthocyanin pigmentation in seedlings and generated a deep purple color in leaves, stems and seeds. Reverse transcription-polymerase chain reaction analysis showed that IbMYB1a expression induced upregulation of several structural genes in the anthocyanin biosynthetic pathway, including 4CL, CHI, F3'H, DFR, AGT, AAT and GST. Furthermore, overexpression of IbMYB1a led to enhanced expression of the AtTT8 (bHLH) and PAP1/AtMYB75 genes. high-performance liquid chromatography analysis revealed that IbMYB1a expression led to the production of cyanidin as a major core molecule of anthocyanidins in Arabidopsis, as occurs in the purple leaves of sweetpotato (cv. Sinzami). This result shows that the IbMYB1a TF is sufficient to induce anthocyanin accumulation in seedlings, leaves, stems and seeds of Arabidopsis plants.
Flower colour and cytochromes P450.
Tanaka Yoshikazu,Brugliera Filippa
Philosophical transactions of the Royal Society of London. Series B, Biological sciences
Cytochromes P450 play important roles in biosynthesis of flavonoids and their coloured class of compounds, anthocyanins, both of which are major floral pigments. The number of hydroxyl groups on the B-ring of anthocyanidins (the chromophores and precursors of anthocyanins) impact the anthocyanin colour, the more the bluer. The hydroxylation pattern is determined by two cytochromes P450, flavonoid 3'-hydroxylase (F3'H) and flavonoid 3',5'-hydroxylase (F3'5'H) and thus they play a crucial role in the determination of flower colour. F3'H and F3'5'H mostly belong to CYP75B and CYP75A, respectively, except for the F3'5'Hs in Compositae that were derived from gene duplication of CYP75B and neofunctionalization. Roses and carnations lack blue/violet flower colours owing to the deficiency of F3'5'H and therefore lack the B-ring-trihydroxylated anthocyanins based upon delphinidin. Successful redirection of the anthocyanin biosynthesis pathway to delphinidin was achieved by expressing F3'5'H coding regions resulting in carnations and roses with novel blue hues that have been commercialized. Suppression of F3'5'H and F3'H in delphinidin-producing plants reduced the number of hydroxyl groups on the anthocyanidin B-ring resulting in the production of monohydroxylated anthocyanins based on pelargonidin with a shift in flower colour to orange/red. Pelargonidin biosynthesis is enhanced by additional expression of a dihydroflavonol 4-reductase that can use the monohydroxylated dihydrokaempferol (the pelargonidin precursor). Flavone synthase II (FNSII)-catalysing flavone biosynthesis from flavanones is also a P450 (CYP93B) and contributes to flower colour, because flavones act as co-pigments to anthocyanins and can cause blueing and darkening of colour. However, transgenic plants expression of a FNSII gene yielded paler flowers owing to a reduction of anthocyanins because flavanones are precursors of anthocyanins and flavones.
Predictability and irreversibility of genetic changes associated with flower color evolution in Penstemon barbatus.
Wessinger Carolyn A,Rausher Mark D
Evolution; international journal of organic evolution
Two outstanding questions in evolutionary biology are whether, and how often, the genetic basis of phenotypic evolution is predictable; and whether genetic change constrains evolutionary reversibility. We address these questions by studying the genetic basis of red flower color in Penstemon barbatus. The production of red flowers often involves the inactivation of one or both of two anthocyanin pathway genes, Flavonoid 3',5'-hydroxylase (F3'5'h) and Flavonoid 3'-hydroxylase (F3'h). We used gene expression and enzyme function assays to determine that redundant inactivating mutations to F3'5'h underlie the evolution of red flowers in P. barbatus. Comparison of our results to previously characterized shifts from blue to red flowers suggests that the genetic change associated with the evolution of red flowers is predictable: when it involves elimination of F3'5'H activity, functional inactivation or deletion of this gene tends to occur; however, when it involves elimination of F3'H activity, tissue-specific regulatory substitutions occur and the gene is not functionally inactivated. This pattern is consistent with emerging data from physiological experiments indicating that F3'h may have pleiotropic effects and is thus subject to purifying selection. The multiple, redundant inactivating mutations to F3'5'h suggest that reversal to blue-purple flowers in this group would be unlikely.
A De novo Transcriptomic Approach to Identify Flavonoids and Anthocyanins "Switch-Off" in Olive (Olea europaea L.) Drupes at Different Stages of Maturation.
Iaria Domenico L,Chiappetta Adriana,Muzzalupo Innocenzo
Frontiers in plant science
Highlights A de novo transcriptome reconstruction of olive drupes was performed in two genotypesGene expression was monitored during drupe development in two olive cultivarsTranscripts involved in flavonoid and anthocyanin pathways were analyzed in Cassanese and Leucocarpa cultivarsBoth cultivar and developmental stage impact gene expression in Olea europaea fruits. During ripening, the fruits of the olive tree (Olea europaea L.) undergo a progressive chromatic change characterized by the formation of a red-brown "spot" which gradually extends on the epidermis and in the innermost part of the mesocarp. This event finds an exception in the Leucocarpa cultivar, in which we observe a destabilized equilibrium between the metabolisms of chlorophyll and other pigments, particularly the anthocyanins whose switch-off during maturation promotes the white coloration of fruits. Despite its importance, genomic information on the olive tree is still lacking. Different RNA-seq libraries were generated from drupes of "Leucocarpa" and "Cassanese" olive genotypes, sampled at 100 and 130 days after flowering (DAF), and were used in order to identify transcripts involved in the main phenotypic changes of fruits during maturation and their corresponding expression patterns. A total of 103,359 transcripts were obtained and 3792 and 3064 were differentially expressed in "Leucocarpa" and "Cassanese" genotypes, respectively, during 100-130 DAF transition. Among them flavonoid and anthocyanin related transcripts such as phenylalanine ammonia lyase (PAL), cinnamate 4-hydroxylase (C4H), 4-coumarate-CoA ligase (4CL), chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), flavonol 3'-hydrogenase (F3'H), flavonol 3'5 '-hydrogenase (F3'5'H), flavonol synthase (FLS), dihydroflavonol 4-reductase (DFR), anthocyanidin synthase (ANS), UDP-glucose:anthocianidin: flavonoid glucosyltransferase (UFGT) were identified. These results contribute to reducing the current gap in information regarding metabolic processes, including those linked to fruit pigmentation in the olive.
Identification of Vitis vinifera L. grape berry skin color mutants and polyphenolic profile.
Ferreira Vanessa,Fernandes Fátima,Pinto-Carnide Olinda,Valentão Patrícia,Falco Virgílio,Martín Juan Pedro,Ortiz Jesús María,Arroyo-García Rosa,Andrade Paula B,Castro Isaura
A germplasm set of twenty-five grapevine accessions, forming eleven groups of possible berry skin color mutants, were genotyped with twelve microsatellite loci, being eleven of them identified as true color mutants. The polyphenolic profiling of the confirmed mutant cultivars revealed a total of twenty-four polyphenols, comprising non-colored compounds (phenolic acids, flavan-3-ols, flavonols and a stilbene) and anthocyanins. Results showed differences in the contribution of malvidin-3-O-glucoside to the characteristic Pinot Noir anthocyanins profile. Regarding the two Pique-Poul colored variants, the lighter variant was richer than the darker one in all classes of compounds, excepting anthocyanins. In Moscatel Galego Roxo the F3'H pathway seems to be more active than F3'5'H, resulting in higher amounts of cyanidin, precursor of the cyanidin derivatives. As far as we are aware, this is the first time that a relationship between the content of polyphenolic compounds is established in groups of grape berry skin color mutant cultivars.
The B-ring hydroxylation pattern of anthocyanins can be determined through activity of the flavonoid 3'-hydroxylase on leucoanthocyanidins.
Schwinn Kathy,Miosic Silvija,Davies Kevin,Thill Jana,Gotame Tek Prasad,Stich Karl,Halbwirth Heidi
MAIN CONCLUSION:In contrast to current knowledge, the B -ring hydroxylation pattern of anthocyanins can be determined by the hydroxylation of leucoanthocyanidins in the 3' position by flavonoid 3'-hydroxylase. The cytochrome P450-dependent monooxygenases flavonoid 3'-hydroxylase (F3'H) and flavonoid 3',5'-hydroxylase (F3'5'H) are key flavonoid enzymes that introduce B-ring hydroxyl groups in positions 3' or 3' and 5', respectively. The degree of B-ring hydroxylation is the major determinant of the hue of anthocyanin pigments. Numerous studies have shown that F3'H and F3'5'H may act on more than one type of anthocyanin precursor in addition to other flavonoids, but it has been unclear whether the anthocyanin precursor of the leucoanthocyanidin type can be hydroxylated as well. We have investigated this in vivo using feeding experiments and in vitro by studies with recombinant F3'H. Feeding leucoanthocyanidins to petal tissue with active hydroxylases resulted in anthocyanidins with increased B-ring hydroxylation relative to the fed leucoanthocyanidin, indicating the presence of 3'-hydroxylating activity (in Petunia and Eustoma grandiflorum Grise.) and 3',5'-hydroxylating activity (in E. grandiflorum Grise.). Tetcyclacis, a specific inhibitor of cytochrome P450-dependent enzymes, abolished this activity, excluding involvement of unspecific hydroxylases. While some hydroxylation could be a consequence of reverse catalysis by dihydroflavonol 4-reductase (DFR) providing an alternative substrate, hydroxylating activity was still present in fed petals of a DFR deficient petunia line. In vitro conversion rates and kinetic data for dLPG (a stable leucoanthocyanidin substrate) were comparable to those for other flavonoids for nine of ten recombinant flavonoid hydroxylases from various taxa. dLPG was a poor substrate for only the recombinant Fragaria F3'Hs. Thus, the B-ring hydroxylation pattern of anthocyanins can be determined at all precursor levels in the pathway.
Transgenic apple plants overexpressing the chalcone 3-hydroxylase gene of Cosmos sulphureus show increased levels of 3-hydroxyphloridzin and reduced susceptibility to apple scab and fire blight.
Hutabarat Olly Sanny,Flachowsky Henryk,Regos Ionela,Miosic Silvija,Kaufmann Christine,Faramarzi Shadab,Alam Mohammed Zobayer,Gosch Christian,Peil Andreas,Richter Klaus,Hanke Magda-Viola,Treutter Dieter,Stich Karl,Halbwirth Heidi
MAIN CONCLUSION:Overexpression of chalcone-3-hydroxylase provokes increased accumulation of 3-hydroxyphloridzin in Malus . Decreased flavonoid concentrations but unchanged flavonoid class composition were observed. The increased 3-hydroxyphlorizin contents correlate well with reduced susceptibility to fire blight and scab. The involvement of dihydrochalcones in the apple defence mechanism against pathogens is discussed but unknown biosynthetic steps in their formation hamper studies on their physiological relevance. The formation of 3-hydroxyphloretin is one of the gaps in the pathway. Polyphenol oxidases and cytochrome P450 dependent enzymes could be involved. Hydroxylation of phloretin in position 3 has high similarity to the B-ring hydroxylation of flavonoids catalysed by the well-known flavonoid 3'-hydroxylase (F3'H). Using recombinant F3'H and chalcone 3-hydroxylase (CH3H) from Cosmos sulphureus we show that F3'H and CH3H accept phloretin to some extent but higher conversion rates are obtained with CH3H. To test whether CH3H catalyzes the hydroxylation of dihydrochalcones in planta and if this could be of physiological relevance, we created transgenic apple trees harbouring CH3H from C. sulphureus. The three transgenic lines obtained showed lower polyphenol concentrations but no shift between the main polyphenol classes dihydrochalcones, flavonols, hydroxycinnamic acids and flavan 3-ols. Increase of 3-hydroxyphloridzin within the dihydrochalcones and of epicatechin/catechin within soluble flavan 3-ols were observed. Decreased activity of dihydroflavonol 4-reductase and chalcone synthase/chalcone isomerase could partially explain the lower polyphenol concentrations. In comparison to the parent line, the transgenic CH3H-lines showed a lower disease susceptibility to fire blight and apple scab that correlated with the increased 3-hydroxyphlorizin contents.
Molecular and Biochemical Analysis of Two Rice Flavonoid 3'-Hydroxylase to Evaluate Their Roles in Flavonoid Biosynthesis in Rice Grain.
Park Sangkyu,Choi Min Ji,Lee Jong Yeol,Kim Jae Kwang,Ha Sun-Hwa,Lim Sun-Hyung
International journal of molecular sciences
Anthocyanins and proanthocyanidins, the major flavonoids in black and red rice grains, respectively, are mainly derived from 3',4'-dihydroxylated leucocyanidin. 3'-Hydroxylation of flavonoids in rice is catalyzed by flavonoid 3'-hydroxylase (F3'H: EC 188.8.131.52). We isolated cDNA clones of the two rice F3'H genes (CYP75B3 and CYP75B4) from Korean varieties of white, black, and red rice. Sequence analysis revealed allelic variants of each gene containing one or two amino acid substitutions. Heterologous expression in yeast demonstrated that CYP75B3 preferred kaempferol to other substrates, and had a low preference for dihydrokaempferol. CYP75B4 exhibited a higher preference for apigenin than for other substrates. CYP75B3 from black rice showed an approximately two-fold increase in catalytic efficiencies for naringenin and dihydrokaempferol compared to CYP75B3s from white and red rice. The F3'H activity of CYP75B3 was much higher than that of CYP75B4. Gene expression analysis showed that CYP75B3, CYP75B4, and most other flavonoid pathway genes were predominantly expressed in the developing seeds of black rice, but not in those of white and red rice, which is consistent with the pigmentation patterns of the seeds. The expression levels of CYP75B4 were relatively higher than those of CYP75B3 in the developing seeds, leaves, and roots of white rice.
Difference in chilling-induced flavonoid profiles, antioxidant activity and chilling tolerance between soybean near-isogenic lines for the pubescence color gene.
Toda Kyoko,Takahashi Ryoji,Iwashina Tsukasa,Hajika Makita
Journal of plant research
Chilling tolerance is an important trait of soybeans [Glycine max (L.) Merr.] produced in cool climates. We previously isolated a soybean flavonoid 3' hydroxylase (F3'H) gene corresponding to the T locus, which controls pubescence and seed coat color. A genetic link between the T gene and chilling tolerance has been reported, although the exact underlying mechanisms remain unclear. Using the soybean near-isogenic lines (NILs) To7B (TT) and To7G (tt), we examined the relationship between chilling injury, antioxidant activity and flavonoid profiles associated with chilling treatment (15°C). Chilling injury was more severe in the second trifoliate leaves of To7G than in those of To7B. Hydrogen peroxide accumulation and lipid peroxidation were enhanced by chilling in To7G. Chilling-induced enhancement of antioxidant activity was more prominent in To7B than in To7G. High performance liquid chromatography analysis indicated that the contents of quercetin glycosides and isorhamnetin glycosides (3',4'-dihydroxylated flavonol derivatives) increase in the second trifoliate leaves of To7B after chilling treatment, whereas the same treatment increased kaempferol glycoside (4'-monohydroxylated flavonol derivatives) content in the corresponding leaves of To7G. Histochemical staining also demonstrated chilling-induced flavonoid accumulation. Microarray analysis and real-time reverse transcription-PCR demonstrated that the transcript levels of soybean F3'H are upregulated by chilling. The differences in chilling injury, antioxidant activity and flavonoid species between the two NILs support the notion that soybean F3'H affects chilling tolerance by increasing antioxidant activity via production of 3',4'-dihydroxylated flavonol derivatives.
Cloning, functional expression, and characterization of a chalcone 3-hydroxylase from Cosmos sulphureus.
Schlangen Karin,Miosic Silvija,Thill Jana,Halbwirth Heidi
Journal of experimental botany
A chalcone 3-hydroxylase (CH3H) cDNA clone was isolated and characterized from Cosmos sulphureus petals accumulating butein (2',3,4,4'-tetrahydroxychalcone) derivatives as yellow flower pigments. The recombinant protein catalyses the introduction of an additional hydroxyl group in the B-ring of chalcones, a reaction with high similarity to the hydroxylation of flavonoids catalysed by the well-studied flavonoid 3'-hydroxylase (F3'H). CH3H shows high specificity for chalcones, but a low F3'H activity was also detected. By contrast, the common F3'H from C. sulphureus does not accept chalcones as substrates and is therefore unlikely to be involved in the creation of the B-ring hydroxylation pattern of the yellow flower pigments. CH3H was primarily expressed in young buds, the main tissue for chalcone pigment formation. Expression levels in open flowers and 3-d-old seedlings were lower and almost no CH3H expression was observed in leaves. F3'H, in contrast, showed the highest expression also in buds, but comparable expression rates in all other tissues tested. Recombinant hybrid proteins constructed from CH3H and F3'H fragments demonstrated that amino acid residues at a substrate recognition site and an insertion of four amino acid residues in a putative loop region have an impact on chalcone acceptance. This is the first identification of a CH3H cDNA from any plant species.
Functional analysis of Antirrhinum kelloggii flavonoid 3'-hydroxylase and flavonoid 3',5'-hydroxylase genes; critical role in flower color and evolution in the genus Antirrhinum.
Ishiguro Kanako,Taniguchi Masumi,Tanaka Yoshikazu
Journal of plant research
The enzymes flavonoid 3'-hydroxylase (F3'H) and flavonoid 3',5'-hydroxylase (F3'5'H) play an important role in flower color by determining the B-ring hydroxylation pattern of anthocyanins, the major floral pigments. F3'5'H is necessary for biosynthesis of the delphinidin-based anthocyanins that confer a violet or blue color to most plants. Antirrhinum majus does not produce delphinidin and lacks violet flower colour while A. kelloggii produces violet flowers containing delphinidin. To understand the cause of this inter-specific difference in the Antirrhinum genus, we isolated one F3'H and two F3'5'H homologues from the A. kelloggii petal cDNA library. Their amino acid sequences showed high identities to F3'Hs and F3'5'Hs of closely related species. Transgenic petunia expressing these genes had elevated amounts of cyanidin and delphinidin respectively, and flower color changes in the transgenics reflected the type of accumulated anthocyanidins. The results indicate that the homologs encode F3'H and F3'5'H, respectively, and that the ancestor of A. majus lost F3'5'H activity after its speciation from the ancestor of A. kelloggii.
Down-regulation of flavonoid 3'-hydroxylase gene expression by virus-induced gene silencing in soybean reveals the presence of a threshold mRNA level associated with pigmentation in pubescence.
Nagamatsu Atsushi,Masuta Chikara,Matsuura Hideyuki,Kitamura Keisuke,Abe Jun,Kanazawa Akira
Journal of plant physiology
Changes in flavonoid content are often manifested as altered pigmentation in plant tissues. Two loci have been identified as controlling pigmentation in soybean pubescence. Of these, the T locus appears to encode flavonoid 3'-hydroxylase (F3'H) protein: the T and t alleles are associated with tawny and gray colors, respectively, in pubescence. We previously down-regulated F3'H gene expression by virus-induced gene silencing (VIGS) in soybean. Despite this successful VIGS, the tawny pubescence pigmentation proved to be unchanged in greenhouse-grown plants. We hypothesized that the reduced mRNA level of the F3'H gene resulting from VIGS remained high enough to induce pigmentation. To verify this hypothesis, in the present study, we performed F3'H VIGS on plants grown under controlled conditions, in which the steady-state mRNA level of the F3'H gene was reduced to approximately 5% of that of greenhouse-grown plants. This VIGS treatment resulted in the loss of tawny pigmentation in pubescence, suggesting that the sf3'h1 gene is involved in the control of pigmentation in pubescence. We detected a marked decrease in target mRNA, an accumulation of short interfering RNAs (siRNAs), and a decrease in quercetin content relative to kaempferol in leaf tissues, indicating that sequence-specific mRNA degradation of the F3'H gene was induced. These results suggest that leaf tissues have a threshold mRNA level of the F3'H gene, which is associated with the occurrence of tawny pigmentation in pubescence. The estimated threshold mRNA level for pigmentation in pubescence was approximately 3% of the steady-state mRNA level of the F3'H gene in greenhouse-grown plants.
Identification of flavonoid 3'-hydroxylase in the yellow flower of Delphinium zalil.
Miyahara Taira,Hamada Arisa,Okamoto Mitsutoshi,Hirose Yukio,Sakaguchi Kimitoshi,Hatano Shoji,Ozeki Yoshihiro
Journal of plant physiology
The flowers of delphinium cultivars owe their coloration to anthocyanins such as delphinidin or pelargonidin derivatives. To date, no delphinium cultivars have been found with red flowers due to the presence of cyanidin derivatives. This suggests that delphiniums do not have cyanidin biosynthesis ability because of the loss of function of flavonoid 3' hydroxylase (F3'H). Here, we show that the wild delphinium species Delphinium zalil (synonym semibarbatum) can accumulate quercetin 3-glucosides in its sepals, presumably through F3'H activity. We isolated F3'H cDNA from D. zalil (DzF3'H) and produced a recombinant enzyme from a yeast transformant. The recombinant DzF3'H protein could convert naringenin, apigenin, dihydrokaempferol and kaempferol to eriodictyol, luteolin, dihydroquercetin and quercetin, respectively. An expression analysis confirmed that blue flowered D. grandiflorum does not express F3'H, and also showed that flavonoid 3',5'-hydroxylase and anthocyanidin synthase do not function in D. zalil sepals. DzF3'H can act as a flavonoid hydroxylase to produce cyanidin accumulation. The introduction of the DzF3'H gene into other delphinium species by conventional breeding may enable development of cultivars with novel flower colors.
QTL mapping and molecular characterization of the classical D locus controlling seed and flower color in Linum usitatissimum (flax).
Sudarshan Gurudatt Pavagada,Kulkarni Manoj,Akhov Leonid,Ashe Paula,Shaterian Hamid,Cloutier Sylvie,Rowland Gordon,Wei Yangdou,Selvaraj Gopalan
The flowers of flax (linseed) are blue-hued, ephemeral and self-pollinating, and the seeds are typically brown. A century-old interest in natural yellow seed variants and a historical model point to recessive alleles in B1, D and G loci being responsible, but the functional aspects had remained unknown. Here, we characterized the "D" locus by quantitative trait loci (QTL) mapping and identified a FLAVONOID 3'5' HYDROXYLASE (F3'5'H) gene therein. It does not belong to the F3'5'H clade, but resembles biochemically characterized F3'Hs (flavonoid 3' hydroxylase) but without F3'H activity. The genome lacks other F3'H or F3'H-like genes. The apparent neo-functionalization from F3'H is associated with a Thr → Ser substitution in a substrate recognition site (SRS). The yellow seed and white flower phenotypes of the classical d mutation was found to be due to one nucleotide deletion that would truncate the deduced product and remove three of the six potential SRS, negatively impacting delphinidin synthesis. Delphinidin is sporadic in angiosperms, and flax has no known pollination syndrome(s) with functional pollinator group(s) that are attracted to blue flowers, raising questions on the acquisition of F3'5'H. The appearance of d allele is suggestive of the beginning of the loss of F3'5'H in this species.
Evaluation of a / fusion gene for its suitability to act as reporter gene in promoter studies in L. 'Rügen'.
Khidr Yehia A,Flachowsky Henryk,Haselmair-Gosch Christian,Thill Jana,Miosic Silvija,Hanke Magda-Viola,Stich Karl,Halbwirth Heidi
Plant cell, tissue and organ culture
A transcription factor gene was previously used as visible marker for successful plant transformation. We combined the transcription factor gene with a gene to test its viability as a non-destructive, visual, double reporter system for functional promoter studies in transgenic strawberry plants. The gene was fused to to provide evidence for promoter activity in red colored cells of transformed plant tissue and to exclude artefacts resulting from stress response or due to other environmental cues. To test this system in a first approach, we evaluated the construct in transgenic strawberries in combination with two constitutive promoters of varying strength, the strong CaMV promoter and a weak () promoter isolated from the ornamental plant mediated transformation of with the construct combined with the CaMV or promoter sequences resulted in the regeneration of 6 and 4 transgenic lines, respectively. A complete red coloration of all plant organs was found in four out of six transgenic lines harboring the construct. Less red coloration of plant organs was found for lines transformed with the construct. The gene shows only limited suitability as a reporter gene for promoter studies in strawberries because weak promoter activity is difficult to distinguish, particularly in tissues showing a strongly colored background such as green leaves. GFP specific fluorescence signals were detectable neither in tissue strongly expressing nor in green tissue of any transgenic line. The reason for this remained unclear but it can be excluded that it was due to incorrect splicing.
Multiple evolution of flavonoid 3',5'-hydroxylase.
Seitz Christian,Ameres Stefanie,Schlangen Karin,Forkmann Gert,Halbwirth Heidi
MAIN CONCLUSION:Multiple F3'5'H evolution from F3'H has occurred in dicotyledonous plants. Efficient pollinator attraction is probably the driving force behind, as this allowed for the synthesis of delphinidin-based blue anthocyanins. The cytochrome P450-dependent monooxygenases flavonoid 3'-hydroxylase (F3'H) and flavonoid 3',5'-hydroxylase (F3'5'H) hydroxylate the B-ring of flavonoids at the 3'- and 3'- and 5'-position, respectively. Their divergence took place early in plant evolution. While F3'H is ubiquitously present in higher plants, the distribution of F3'5'H is scattered. Here, we report that F3'5'H has repeatedly evolved from F3'H precursors at least four times in dicotyledonous plants: In the Asteraceae, we identified F3'5'Hs specific for the subfamilies Cichorioideae and Asteroideae, and additionally an F3'5'H that seems to be specific for the genus Echinops of the subfamily Carduoideae; moreover, characterisation of a sequence from Billardiera heterophylla (formerly Sollya heterophylla) (Pittosporaceae) showed that the independent evolution of an F3'5'H has occurred at least once also in another family. The evolution of F3'5'H from an F3'H precursor represents a gain of enzymatic function, probably triggered by an amino acid change at one position of substrate recognition site 6. The gain of F3'5'H activity allows for the synthesis of delphinidin-based anthocyanins which usually provide the basis for lilac to blue flower colours. Therefore, the need for an efficient pollinator attraction is probably the driving force behind the multiple F3'5'H evolution.
Expression level of a flavonoid 3'-hydroxylase gene determines pathogen-induced color variation in sorghum.
Mizuno Hiroshi,Yazawa Takayuki,Kasuga Shigemitsu,Sawada Yuji,Ogata Jun,Ando Tsuyu,Kanamori Hiroyuki,Yonemaru Jun-ichi,Wu Jianzhong,Hirai Masami Yokota,Matsumoto Takashi,Kawahigashi Hiroyuki
BMC research notes
BACKGROUND:Sorghum (Sorghum bicolor L. Moench) accumulates 3-deoxyanthocyanidins and exhibits orange to purple coloration on parts of the leaf in response to infection with the fungus Bipolaris sorghicola. We aimed to identify the key genes determining this color variation. RESULTS:Sorghum populations derived from Nakei-MS3B and M36001 accumulated apigeninidin, or both apigeninidin and luteolinidin, in different proportions in lesions caused by B. sorghicola infection, suggesting that the relative proportions of the two 3-deoxyanthocyanidins determine color variation. QTL analysis and genomic sequencing indicated that two closely linked loci on chromosome 4, containing the flavonoid 3'-hydroxylase (F3'H) and Tannin1 (Tan1) genes, were responsible for the lesion color variation. The F3'H locus in Nakei-MS3B had a genomic deletion resulting in the fusion of two tandemly arrayed F3'H genes. The recessive allele at the Tan1 locus derived from M36001 had a genomic insertion and encoded a non-functional WD40 repeat transcription factor. Whole-mRNA sequencing revealed that expression of the fused F3'H gene was conspicuously induced in purple sorghum lines. The levels of expression of F3'H matched the relative proportions of apigeninidin and luteolinidin. CONCLUSIONS:Expression of F3'H is responsible for the synthesis of luteolinidin; the expression level of this gene is therefore critical in determining color variation in sorghum leaves infected with B. sorghicola.
Expression of and Is Associated with Color Variation in Tan-Colored Injured Leaves of Sorghum.
Mizuno Hiroshi,Yazawa Takayuki,Kasuga Shigemitsu,Sawada Yuji,Kanamori Hiroyuki,Ogo Yuko,Hirai Masami Yokota,Matsumoto Takashi,Kawahigashi Hiroyuki
Frontiers in plant science
Sorghum ( L. Moench) exhibits various color changes in injured leaves in response to cutting stress. Here, we aimed to identify key genes for the light brown and dark brown color variations in tan-colored injured leaves of sorghum. For this purpose, sorghum M36001 (light brown injured leaves), Nakei-MS3B (purple), and a progeny, #7 (dark brown), from Nakei-MS3B × M36001, were used. Accumulated pigments were detected by using high-performance liquid chromatography: M36001 accumulated only apigenin in its light brown leaves; #7 accumulated both luteolin and a small amount of apigenin in its dark brown leaves, and Nakei-MS3B accumulated 3-deoxyanthocyanidins (apigeninidin and luteolinidin) in its purple leaves. Apigenin or luteolin glucoside derivatives were also accumulated, in different proportions. Differentially expressed genes before and after cutting stress were identified by using RNA sequencing (RNA-seq). Integration of our metabolic and RNA-seq analyses suggested that expression of only led to the synthesis of apigenin in M36001, expression of both and led to the synthesis of apigenin and luteolin in #7, and expression of both and led to the synthesis of 3-deoxyanthocyanidins in Nakei-MS3B. These results suggest that expression of is related to the synthesis of flavones (apigenin and luteolin) and the expression level of is related to the balance of apigenin and luteolin. Expression of and is thus associated with dark or light brown coloration in tan-colored injured leaves of sorghum.
Differential expression of flavonoid 3'-hydroxylase during fruit development establishes the different B-ring hydroxylation patterns of flavonoids in Fragaria × ananassa and Fragaria vesca.
Thill Jana,Miosic Silvija,Gotame Tek Prasad,Mikulic-Petkovsek Maja,Gosch Christian,Veberic Robert,Preuss Anja,Schwab Wilfried,Stampar Franci,Stich Karl,Halbwirth Heidi
Plant physiology and biochemistry : PPB
Flavonoid 3'-hydroxylase (F3'H) was studied for the first time in different Fragaria species. The cDNA clones isolated from unripe and ripe fruits of Fragaria x ananassa (garden strawberry) and Fragaria vesca (wild strawberry) showed high similarity (99% at the amino acid level) to the publically available F. vesca genome sequence and no significant differences could be identified between species and developmental stages of the fruits. In contrast, the genomic F3'H clones showed differences in the non-coding regions and 5'-flanking elements. The recombinant F3'Hs were functionally active and showed high specificity for naringenin, dihydrokaempferol, and kaempferol, whereas apigenin was only a minor substrate. During fruit development, a clear difference in the F3'H expression was observed between F. × ananassa and F. vesca. While a drastic decline of F3'H expression occurred during fruit ripening in F. × ananassa, F3'H in F. vesca was highly expressed in all stages. This was reflected by the anthocyanin composition, which showed a prevalence of pelargonidin in ripe fruits of F. × ananassa, whereas F. vesca had a high content of cyanidin. Screening of 17 berry species for their anthocyanin and flavonol composition showed that the prevalence of monohydroxylated anthocyanins makes garden strawberry unique among all other fruit species indicating that selection of bright red color during strawberry breeding, which consumers typically associate with freshness and ripeness, has selected phenotypes with a special biochemical background.
A molecular assessment of the genetic model of spathe color inheritance in Anthurium andraeanum (Hort.).
Gopaulchan David,Umaharan Pathmanathan,Lennon Adrian M
Past genetic studies have shown three independent loci designated O, R and M control spathe color in Anthurium andraeanum (Hort.). To evaluate the genetic model and to understand the control of anthocyanin biosynthesis at the molecular level, the expression of the anthocyanin biosynthetic genes, CHS, F3H, DFR, ANS and F3'H, was examined at the mRNA and protein levels and correlated to anthocyanin content and spathe color in eight genetically characterized anthurium cultivars representing different states of the O, R and M loci. The results showed that the expression of F3H and ANS was co-regulated by a putative transcription factor encoded by the R locus, and the expression of DFR was regulated by a putative transcription factor encoded by the O locus. White cultivars, which were in the homozygous recessive state for either O or R or both, exhibited reduced expression of the anthocyanin biosynthetic genes and hence had negligible levels of anthocyanin. Cultivars that were mm displayed reduced expression of F3'H suggesting that it may either encode a defective form of the F3'H gene or a regulator that controls its expression. Additionally, a correlation between anthocyanin abundance and the expression of F3'H in the red cultivars suggested that F3'H expression may be a key control point in the regulation of anthocyanin biosynthesis in anthurium and hence plays a major role in influencing the shade intensity in red cultivars. These findings provide evidence in support of the genetic model for color inheritance in the spathe.
Duplicated and genes in barley genome.
Vikhorev Alexander V,Strygina Ksenia V,Khlestkina Elena K
Background:Anthocyanin compounds playing multiple biological functions can be synthesized in different parts of barley ( L.) plant. The diversity of anthocyanin molecules is related with branching the pathway to alternative ways in which dihydroflavonols may be modified either with the help of flavonoid 3'-hydroxylase (3') or flavonoid 3',5'-hydroxylase (3'5')-the cytochrome P450-dependent monooxygenases. The ' and '5' gene families are among the least studied anthocyanin biosynthesis structural genes in barley. The aim of this study was to identify and characterise duplicated copies of the ' and 3'5' genes in the barley genome. Results:Four copies of the '5' gene (on chromosomes 4HL, 6HL, 6HS and 7HS) and two copies of the ' gene (on chromosomes 1HL and 6HS) were identified in barley genome. These copies have either one or two introns. Amino acid sequences analysis demonstrated the presence of the flavonoid hydroxylase-featured conserved motifs in all copies of the 3' and 3'5' genes with the exception of 3'5'-3 carrying a loss-of-function mutation in a conservative cytochrome P450 domain. It was shown that the divergence between ' and '5' occurred 129 million years ago (MYA) before the emergence of monocot and dicot plant species. The ' copy approximately occurred 80 MYA; the appearance of '5' copies occurred 8, 36 and 91 MYA. qRT-PCR analysis revealed the tissue-specific activity for some copies of the studied genes. The '-1 gene was transcribed in aleurone layer, lemma and pericarp (with an increased level in the coloured pericarp), whereas the ' gene was expressed in stems only. The '5' gene was expressed only in the aleurone layer, and in a coloured aleurone its expression was 30-fold higher. The transcriptional activity of '5' was detected in different tissues with significantly higher level in uncoloured genotype in contrast to coloured ones. The '5' gene expressed neither in stems nor in aleurone layer, lemma and pericarp. The '5' gene copy was weakly expressed in all tissues analysed. Conclusion:' and '5'-coding genes involved in anthocyanin synthesis in were identified and characterised, from which the copies designated ', ', '5' and '5' demonstrated tissue-specific expression patterns. Information on these modulators of the anthocyanin biosynthesis pathway can be used in future for manipulation with synthesis of diverse anthocyanin compounds in different parts of barley plant. Finding both the copies with tissue-specific expression and a copy undergoing pseudogenization demonstrated rapid evolutionary events tightly related with functional specialization of the duplicated members of the cytochrome P450-dependent monooxygenases gene families.
The rare orange-red colored Euphorbia pulcherrima cultivar 'Harvest Orange' shows a nonsense mutation in a flavonoid 3'-hydroxylase allele expressed in the bracts.
Nitarska Daria,Stefanini Carmen,Haselmair-Gosch Christian,Miosic Silvija,Walliser Benjamin,Mikulic-Petkovsek Maja,Regos Ionela,Slatnar Ana,Debener Thomas,Terefe-Ayana Diro,Vilperte Vinicius,Hadersdorfer Johannes,Stich Karl,Halbwirth Heidi
BMC plant biology
BACKGROUND:Commercially available poinsettia (Euphorbia pulcherrima) varieties prevalently accumulate cyanidin derivatives and show intense red coloration. Orange-red bract color is less common. We investigated four cultivars displaying four different red hues with respect to selected enzymes and genes of the anthocyanin pathway, putatively determining the color hue. RESULTS:Red hues correlated with anthocyanin composition and concentration and showed common dark red coloration in cultivars 'Christmas Beauty' and 'Christmas Feeling' where cyanidin derivatives were prevalent. In contrast, orange-red bract color is based on the prevalent presence of pelargonidin derivatives that comprised 85% of the total anthocyanin content in cv. 'Premium Red' and 96% in cv. 'Harvest Orange' (synonym: 'Orange Spice'). cDNA clones of flavonoid 3'-hydroxylase (F3'H) and dihydroflavonol 4-reductase (DFR) were isolated from the four varieties, and functional activity and substrate specificity of the corresponding recombinant enzymes were studied. Kinetic studies demonstrated that poinsettia DFRs prefer dihydromyricetin and dihydroquercetin over dihydrokaempferol, and thus, favor the formation of cyanidin over pelargonidin. Whereas the F3'H cDNA clones of cultivars 'Christmas Beauty', 'Christmas Feeling', and 'Premium Red' encoded functionally active enzymes, the F3'H cDNA clone of cv. 'Harvest Orange' contained an insertion of 28 bases, which is partly a duplication of 20 bases found close to the insertion site. This causes a frameshift mutation with a premature stop codon after nucleotide 132 and, therefore, a non-functional enzyme. Heterozygosity of the F3'H was demonstrated in this cultivar, but only the mutated allele was expressed in the bracts. No correlation between F3'H-expression and the color hue could be observed in the four species. CONCLUSIONS:Rare orange-red poinsettia hues caused by pelargonidin based anthocyanins can be achieved by different mechanisms. F3'H is a critical step in the establishment of orange red poinsettia color. Although poinsettia DFR shows a low substrate specificity for dihydrokaempferol, sufficient precursor for pelargonidin formation is available in planta, in the absence of F3'H activity.
The soybean F3'H protein is localized to the tonoplast in the seed coat hilum.
Toda Kyoko,Kuroiwa Haruko,Senthil Kalaiselvi,Shimada Norimoto,Aoki Toshio,Ayabe Shin-ichi,Shimada Setsuko,Sakuta Masaaki,Miyazaki Yasumasa,Takahashi Ryoji
We previously isolated a soybean (Glycine max (L.) Merr.) flavonoid 3'-hydroxylase (F3'H) gene (sf3'h1) corresponding to the T locus, which controls pubescence and seed coat color, from two near-isogenic lines (NILs), To7B (TT) and To7G (tt). The T allele is also associated with chilling tolerance. Here, Western-blot analysis shows that the sf3'h1 protein was predominantly detected in the hilum and funiculus of the immature seed coat in To7B, whereas sf3'h1 was not detected in To7G. A truncated sf3'h1 protein isolated from To7G was detected only upon enrichment by immunoprecipitation. An analysis using diphenylboric acid 2-aminoethyl ester (DBPA) staining revealed that flavonoids accumulated in the hilum and the funiculus in both To7B and To7G. Further, the scavenging activity of the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical in methanol extracts from the funiculus and hilum of To7B was higher than that of To7G. Moreover, the enzymatic activity of F3'H was detected using microsomal fractions from yeast transformed with sf3'h1 from To7B, but not from To7G. These results indicate that sf3'h1 is involved in flavonoid biosynthesis in the seed coat and affects the antioxidant properties of those tissues. As shown by immunofluorescence microscopy, the sf3'h1 protein was detected primarily around the vacuole in the parenchymatic cells of the hilum in To7B. Further immunoelectron microscopy detected sf3'h1 protein on the membranous structure of the vacuole. Based on these observations, we conclude that F3'H, which is a cytochrome P450 monooxygenase and has been found to be localized to the ER in other plant systems, is localized in the tonoplast in soybean.