The transmembrane protein FgSho1 regulates fungal development and pathogenicity via the MAPK module Ste50-Ste11-Ste7 in Fusarium graminearum.
Gu Qin,Chen Yun,Liu Ye,Zhang Chengqi,Ma Zhonghua
The New phytologist
The mitogen-activated protein kinase (MAPK) signaling pathways have been characterized in Fusarium graminearum. Currently, the upstream sensors of these pathways are unknown. Biological functions of a transmembrane protein FgSho1 were investigated using a target gene deletion strategy. The relationship between FgSho1 and the MAPK cassette FgSte50-Ste11-Ste7 was analyzed in depth. The transmembrane protein FgSho1 is required for conidiation, full virulence, and deoxynivalenol (DON) biosynthesis in F. graminearum. Furthermore, FgSho1 and FgSln1 have an additive effect on virulence of F. graminearum. The yeast two-hybrid, coimmunoprecipitation, colocalization and affinity capture-mass spectrometry analyses strongly indicated that FgSho1 physically interacts with the MAPK module FgSte50-Ste11-Ste7. Similar to the FgSho1 mutant, the mutants of FgSte50, FgSte11, and FgSte7 were defective in conidiation, pathogenicity, and DON biosynthesis. In addition, FgSho1 plays a minor role in the response to osmotic stress but it is involved in the cell wall integrity pathway, which is independent of the module FgSte50-Ste11-Ste7 in F. graminearum. Collectively, results of this study strongly indicate that FgSho1 regulates fungal development and pathogenicity via the MAPK module FgSte50-Ste11-Ste7 in F. graminearum, which is different from what is known in the budding yeast Saccharomyces cerevisiae.
Multiple point mutations in PsORP1 gene conferring different resistance levels to oxathiapiprolin confirmed using CRISPR-Cas9 in Phytophthora sojae.
Miao Jianqiang,Liu Xiaofei,Li Guixiang,Du Xiaoran,Liu Xili
Pest management science
BACKGROUND:Oxathiapiprolin is among the first commercial oxysterol-binding protein inhibitors (OSBPIs) developed by DuPont Corporation and shows excellent activity against plant-pathogenic oomycetes. Although more than 21 target site mutations have been identified in insensitive oomycetes, only G770V, G839W, and ΔN837 have been verified to confer oxathiapiprolin resistance in Phytophthora capsici or P. sojae. The effect of other mutations on OSBPIs sensitivity requires urgent investigation. RESULTS:P. sojae transformants containing 16 mutations of PsORP1 were recovered using the CRISPR-Cas9 system. Transformants containing L733W, S768F, S768Y, N837Y, N837F, P861H, L863W, or I877Y showed high oxathiapiprolin resistance, with resistant factors (RFs) > 3000. Point mutations S768K, S768I, G770L, G770P, G770A, ΔG818/F819, N837I, and I877F exhibited low resistance, with RFs < 80. Phenotype assays revealed that the most highly resistant transformants showed enhanced or similar pathogenicity, oospore production, and cyst gemination. However, most transformants displayed decreased sporangia and zoospore production compared with parental wild-type P6497. CONCLUSION:This study demonstrated that L733W, S768F, S768Y, N837Y, N837F, P861H, L863W, and I877Y in PsORP1 confer high oxathiapiprolin resistance in P. sojae.
Genome-wide functional analysis reveals that autophagy is necessary for growth, sporulation, deoxynivalenol production and virulence in Fusarium graminearum.
Lv Wuyun,Wang Chunyan,Yang Nan,Que Yawei,Talbot Nicholas J,Wang Zhengyi
Autophagy is a conserved cellular recycling and trafficking pathway in eukaryotic cells and has been reported to be important in the virulence of a number of microbial pathogens. Here, we report genome-wide identification and characterization of autophagy-related genes (ATGs) in the wheat pathogenic fungus Fusarium graminearum. We identified twenty-eight genes associated with the regulation and operation of autophagy in F. graminearum. Using targeted gene deletion, we generated a set of 28 isogenic mutants. Autophagy mutants were classified into two groups by differences in their growth patterns. Radial growth of 18 Group 1 ATG mutants was significantly reduced compared to the wild-type strain PH-1, while 10 Group 2 mutants grew normally. Loss of any of the ATG genes, except FgATG17, prevented the fungus from causing Fusarium head blight disease. Moreover, subsets of autophagy genes were necessary for asexual/sexual differentiation and deoxynivalenol (DON) production, respectively. FgATG1 and FgATG5 were investigated in detail and showed severe defects in autophagy. Taken together, we conclude that autophagy plays a critical role in growth, asexual/sexual sporulation, deoxynivalenol production and virulence in F. graminearum.
Vps13-Mcp1 interact at vacuole-mitochondria interfaces and bypass ER-mitochondria contact sites.
John Peter Arun T,Herrmann Beatrice,Antunes Diana,Rapaport Doron,Dimmer Kai Stefan,Kornmann Benoît
The Journal of cell biology
Membrane contact sites between endoplasmic reticulum (ER) and mitochondria, mediated by the ER-mitochondria encounter structure (ERMES) complex, are critical for mitochondrial homeostasis and cell growth. Defects in ERMES can, however, be bypassed by point mutations in the endosomal protein Vps13 or by overexpression of the mitochondrial protein Mcp1. How this bypass operates remains unclear. Here we show that the mitochondrial outer membrane protein Mcp1 functions in the same pathway as Vps13 by recruiting it to mitochondria and promoting its association to vacuole-mitochondria contacts. Our findings support a model in which Mcp1 and Vps13 work as functional effectors of vacuole-mitochondria contact sites, while tethering is mediated by other factors, including Vps39. Tethered and functionally active vacuole-mitochondria interfaces then compensate for the loss of ERMES-mediated ER-mitochondria contact sites.
A pilot study of therapeutic plasma exchange for serious SARS CoV-2 disease (COVID-19): A structured summary of a randomized controlled trial study protocol.
Faqihi Fahad,Alharthy Abdulrahman,Alodat Mohammed,Asad Daood,Aletreby Waleed,Kutsogiannis Demetrios J,Brindley Peter G,Karakitsos Dimitrios
OBJECTIVES:To evaluate the safety of therapeutic plasma exchange (TPE) in adult patients with serious/life-threatening COVID-19 requiring intensive care unit (ICU) admission, and associated 28-day mortality. Serious and life threatening COVID-19 are defined as per published literature (please, refer to the full protocol, Additional file 1). The rationale is that TPE can remove interleukins-3, 6, 8, 10, interferon-gamma and tumor necrosis factor-alpha. Thus, it may reduce the cytokine release syndrome associated with fulminant COVID-19 disease. TRIAL DESIGN:Pilot, interventional, open-label, randomized controlled multicenter trial. PARTICIPANTS:Inclusion criteria are: 1) age ≥ 18 years old; 2) intubation and intensive care unit (ICU) admission; 3) serious and/or life-threatening COVID-19 (please, refer to the full protocol, Additional file 1). SARS-CoV-2 infection is confirmed by Real-Time-Polymerase-Chain-Reaction (RT-PCR) assays using QuantiNova Probe RT-PCR kit (Qiagen) in a Light-Cycler 480 real-time PCR system (Roche, Basel, Switzerland). Exclusion criteria are: 1) previous allergic reaction to plasma exchange or its ingredients (i.e., sodium citrate), 2) two consecutive negative RT-PCR tests for SARS-CoV-2 at least 24 hours apart, 3) mild COVID-19 not requiring ICU admission and 4) terminally ill patients receiving palliative care. The primary site will be King Saud Medical City (KSMC), Riyadh, Kingdom of Saudi Arabia (KSA). Also, the study will run in ICUs (Ministry of Health Cluster 1; Riyadh) and other centers in KSA pending their institutional review board (IRB) approval. INTERVENTIONS AND COMPARATOR:The intervention group will receive TPE, plus empiric treatment for COVID-19. TPE is administered using the Spectra Optia TM Apheresis System equipped with the Depuro D2000 Adsorption Cartridge (Terumo BCT Inc., USA). The first dose is 1.5 plasma volumes, followed by one plasma volume on alternate days or daily for five to seven total treatments. Spectra Optia TM Apheresis System operates with acid-citrate dextrose anticoagulant (ACDA) as per Kidney Disease Improving Global Outcomes (KDIGO) 2019 guidelines. Plasma is replaced with albumin 5% or fresh frozen plasma in patients with coagulopathy (prothrombin time >37 seconds; international normalized ratio >3; activated partial thromboplastin time >100 or fibrinogen level <100 mg/d). TPE sessions are performed daily over four hours and laboratory markers measured daily. The comparators are controls not receiving TPE but usual empiric treatment for COVID-19 as per institutional, national and international recommendations. Both groups will receive standard ICU supportive care. MAIN OUTCOMES:Primary study end-point is 28-day mortality and safety of TPE in serious and/or life-threatening COVID-19. Safety will be evaluated by the documentation of any pertinent adverse and/or serious adverse effects related to TPE as per institutional, national and international (Food and Drug Administration) guidelines. Secondary outcomes are: i) improvement in Sequential Organ Function Assessment (SOFA) score ; ii) changes in inflammatory markers: serum C-reactive protein, lactate dehydrogenase, ferritin, d-dimers and interleukin-6; iii) days on mechanical ventilation and ICU length of stay. RANDOMIZATION:Eligible consented patients are randomized (1:1 allocation) after stratification by ICU center and two PaO2/FIO2 ratio categories (> 150 and ≤ 150). Randomization occurs in variable block sizes of four to eight patients. A web-based randomization service, randomize.net, is used to allocate patients to their respective strata prior to the intervention or control therapy. BLINDING (MASKING):Given the visibility of TPE machinery, the intervention will be unblinded; hence, no enrollment concealment will be expedited. The lack of allocation concealment will be mitigated by several measures (please, refer to the full protocol, Additional file 1). NUMBERS TO BE RANDOMIZED (SAMPLE SIZE):This pilot randomized trial aims to recruit a convenience sample of patients with serious and/or life-threatening COVID-19. Therefore, at least 20 patients are to be randomized to each group per participating center. We are hoping to consent and randomize approximately 60 patients in each group over a 3 to 6 months period giving a total of 120 participants. TRIAL STATUS:The protocol version 1 was approved 29/04/2020. Recruitment is ongoing, and began on 01/05/2020. We estimate completion by 29/10/2020. TRIAL REGISTRATION:Registered at ISRCTN on 18/05/2020 (ISRCTN21363594; doi.10.1186/ ISRCTN21363594). FULL PROTOCOL:The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest of expediting dissemination of this material, the familiar formatting has been eliminated; this letter serves as a summary of the key elements of the full protocol.