Symbiosis, virulence and natural-product biosynthesis in entomopathogenic bacteria are regulated by a small RNA.
Neubacher Nick,Tobias Nicholas J,Huber Michaela,Cai Xiaofeng,Glatter Timo,Pidot Sacha J,Stinear Timothy P,Lütticke Anna Lena,Papenfort Kai,Bode Helge B
Photorhabdus and Xenorhabdus species have mutualistic associations with nematodes and an entomopathogenic stage in their life cycles. In both stages, numerous specialized metabolites are produced that have roles in symbiosis and virulence. Although regulators have been implicated in the regulation of these specialized metabolites, how small regulatory RNAs (sRNAs) are involved in this process is not clear. Here, we show that the Hfq-dependent sRNA, ArcZ, is required for specialized metabolite production in Photorhabdus and Xenorhabdus. We discovered that ArcZ directly base-pairs with the mRNA encoding HexA, which represses the expression of specialized metabolite gene clusters. In addition to specialized metabolite genes, we show that the ArcZ regulon affects approximately 15% of all transcripts in Photorhabdus and Xenorhabdus. Thus, the ArcZ sRNA is crucial for specialized metabolite production in Photorhabdus and Xenorhabdus species and could become a useful tool for metabolic engineering and identification of commercially relevant natural products.
Nglycosylation shields apoplastic effector PsXEG1 from a specific host aspartic protease.
Xia Yeqiang,Ma Zhenchuan,Qiu Min,Guo Baodian,Zhang Qi,Jiang Haibin,Zhang Baiyu,Lin Yachun,Xuan Mingrun,Sun Liang,Shu Haidong,Xiao Junhua,Ye Wenwu,Wang Yan,Wang Yiming,Dong Suomeng,Tyler Brett M,Wang Yuanchao
Proceedings of the National Academy of Sciences of the United States of America
Hosts and pathogens are engaged in a continuous evolutionary struggle for physiological dominance. A major site of this struggle is the apoplast. In -soybean interactions, PsXEG1, a pathogen-secreted apoplastic endoglucanase, is a key focal point of this struggle, and the subject of two layers of host defense and pathogen counterdefense. Here, we show that N-glycosylation of PsXEG1 represents an additional layer of this coevolutionary struggle, protecting PsXEG1 against a host apoplastic aspartic protease, GmAP5, that specifically targets PsXEG1. This posttranslational modification also attenuated binding by the previously described host inhibitor, GmGIP1. N-glycosylation of PsXEG1 at N174 and N190 inhibited binding and degradation by GmAP5 and was essential for 's full virulence contribution, except in GmAP5-silenced soybeans. Silencing of GmAP5 reduced soybean resistance against WT but not against deletion strains of The crucial role of N-glycosylation within the three layers of defense and counterdefense centered on PsXEG1 highlight the critical importance of this conserved apoplastic effector and its posttranslational modification in -host coevolutionary conflict.