Abstract
SummaryMany bacterial phytopathogens employ effectors secreted through the type‐III secretion system to suppress plant innate immune responses. The Xanthomonas type‐III secreted non‐TAL effector protein Xanthomonas outer protein Q (XopQ) exhibits homology to nucleoside hydrolases. Previous work indicated that mutations which affect the biochemical activity of XopQ fail to affect its ability to suppress rice innate immune responses, suggesting that the effector might be acting through some other pathway or mechanism. In this study, we show that XopQ interacts in yeast and in planta with two rice 14‐3‐3 proteins, Gf14f and Gf14g. A serine to alanine mutation (S65A) of a 14‐3‐3 interaction motif in XopQ abolishes the ability of XopQ to interact with the two 14‐3‐3 proteins and to suppress innate immunity. Surprisingly, the S65A mutant gains the ability to interact with a third 14‐3‐3 protein that is a negative regulator of innate immunity. The XopQS65A mutant is an inducer of rice immune responses and this property is dominant over the wild‐type function of XopQ. Taken together, these results suggest that XopQ targets the rice 14‐3‐3 mediated immune response pathway and that its differential phosphorylation might enable interaction with alternative 14‐3‐3 proteins.
Highlights
Plants can perceive pathogens by recognition of conserved molecular signatures of microorganisms, which are called as pathogen-associated molecular patterns (or PAMPs, e.g.In order to counteract plant defence responses, many Gram-negative phytopathogenic bacteria use effectors secreted through the type-III secretion system (T3SS) to suppress PTI, helping in the establishment of the bacterium in the plant (Akimoto-Tomiyama et al, 2012; Hauck et al, 2003; Jones and Dangl, 2006)
The results suggest that X. oryzae pv. oryzae Xanthomonas outer protein Q (XopQ) can interact with several rice 14-3-3 proteins and that this interaction is important for the ability of the protein to modulate rice innate immunity
The XopQ protein was tagged with the DNA-binding domain (BD) of the pDEST32 vector (Invitrogen) as bait, creating the fusion protein BD::XopQ, and each of the eight rice 14-3-3 proteins were tagged with the activation domain (AD) of the pDEST22 vector (Invitrogen), creating the AD::14-3-3 fusion proteins as prey
Summary
Plants can perceive pathogens by recognition of conserved molecular signatures of microorganisms, which are called as pathogen-associated molecular patterns (or PAMPs, e.g. In order to counteract plant defence responses, many Gram-negative phytopathogenic bacteria use effectors secreted through the type-III secretion system (T3SS) to suppress PTI, helping in the establishment of the bacterium in the plant (Akimoto-Tomiyama et al, 2012; Hauck et al, 2003; Jones and Dangl, 2006). An additional layer is added to plant–pathogen interactions by the observation that some effectors secreted through the bacterial T3SS are able to suppress ETI. Previous studies highlighted examples of pathways which are hijacked by typeIII effectors, e.g. the mitogen-activated protein kinase (MAPK) pathway by XopAU (Teper et al, 2018) or the proteasomal pathway by the interaction of the type-III effector XopP with the E3 ubiquitin ligase PUB44 (Ishikawa et al, 2014).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
