Silencing GmFLS2 enhances the susceptibility of soybean to bacterial pathogen through attenuating the activation of GmMAPK signalling pathway.

Reference Report for AP20210625.1

Title:	Silencing GmFLS2 enhances the susceptibility of soybean to bacterial pathogen through attenuating the activation of GmMAPK signalling pathway.
Authors:	Tian, S., Liu, D., Zhong, C., Xu, H., Yang, S., Fang, Y., Ran, J., Liu, J.
Source:	Tian et al. 2020 Plant Science, 292:110386
Abstract:	The plasma membrane (PM)-localized receptor-like kinases (RLKs) play important roles in pathogen defense. One of the first cloned RLKs is theArabidopsisreceptor kinase FLAGELLIN SENSING 2 (FLS2), which specifically recognizes a conserved 22 amino acid N-terminal sequence ofPseudomonas syringae pvtomatoDC3000 (Pst) flagellin protein (flg22). Although extensively studied inArabidopsis, the functions of RLKs in crop plants remain largely uninvestigated. To understand the roles of RLKs in soybean (Glycine max),GmFLS2was silencedviavirus induced gene silencing (VIGS) mediated byBean pod mottle virus(BPMV). No significant morphological differences were observed betweenGmFLS2-silenced plants and the vector control plants. However, silencingGmFLS2significantly enhanced the susceptibility of the soybean plants toPseudomonas syringae pvglycinea(Psg). Kinase activity assay showed that silencingGmFLS2significantly reduced the phosphorylation level ofGmMPK6 in response to flg22 treatment. However, reduced phosphorylation level of bothGmMPK3 andGmMPK6 in response toPsginfection was observed inGmFLS2-silenced plants, implying that defense response is likely transduced through activation of the downstreamGmMAPK signaling pathway upon recognition of bacterial pathogen byGmFLS2. The core peptides of flg22 fromPstandPsgwere highly conserved and only 4 amino acid differences were seen at their N-termini. Interestingly, it appeared that thePsg-flg22 was more effective in activating soybean MAPKs than activating Arabidopsis MAPKs, and conversely,Pst-flg22was more effective in activating Arabidopsis MAPKs than activating soybean MAPKs, suggesting that the cognate recognition is more potent than heterologous recognition in activating downstream signaling. Taken together, our results suggest that the function of FLS2 is conserved in immunity against bacteria pathogens across different plant species.

Funded by the USDA-ARS. Developed by the USDA-ARS SoyBase and Legume Clade Database group at the Iowa State University, Ames, IA

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