P-225 - Recognition specificities of YopJ family effectors by NbPtr1 and NbZAR1/JIM2 immune complex in Nicotiana benthamiana

Plants are constantly threatened by pathogens, which release effector proteins to manipulate host physiology for survival. In turn, plants have evolved immune mechanisms to detect effectors. Among them, nucleotide-binding leucine-rich repeat receptors (NLRs) play a key role by recognizing effectors directly or indirectly and triggering immune responses, such as the hypersensitive response (HR). YopJ family effectors are highly conserved across bacterial genera causing crop diseases. In the model Solanaceae Nicotiana benthamiana, two NLRs homologs of Pseudomonas tomato race 1 (NbPtr1) and of HOPZ-ACTIVATED RESISTANCE 1 (NbZAR1) recognize independently the YopJ family effectors HopZ5 and XopJ2. Additionally, NbZAR1 and its cognate kinase JIM2 can detect XopJ4 . To determine whether other YopJ family effectors are recognized, we co-expressed effectors with JIM2 in N. benthamiana and monitored cell death occurrence. We identified 12 YopJ family effectors recognized either by NbZAR1 alone or independently by NbZAR1 and NbPtr1. By assessing YopJ family effector-triggered HR in the presence of the deacetylase Suppressor of AvrBsT-elicited Resistance 1 (SOBER1), we further classified YopJ effectors into subgroups that likely reflect distinct modes of perception by the NLRs. Collectively, this study lays the foundation for comparative structural and biochemical analyses of YopJ family effectors and the recognition specificity of NbZAR1 and NbPtr1.