Comparative analysis of NLR-mediated recognition of a bacterial effector AvrRpt2 in Malus and Arabidopsis
K. SOHN (1), M. Prokchorchik (2) (1) Postech, Korea; (2) Massey University, New Zealand

Plant pathogenic bacteria, Pseudomonas syringae and Erwinia amylovora, translocate a type III secretion-dependent effector protein, AvrRpt2, in host plant cells. AvrRpt2 is a cysteine protease and cleaves its host target protein RIN4. AvrRpt2-directed cleavage of RIN4 is recognized by CC-NB-LRR type immune receptors RPS2 and MR5 in Arabidopsis and Malus, respectively. Interestingly, RPS2 and MR5, although both recognize AvrRpt2, do not share significant sequence homology. We found that RPS2 but not MR5 shows autoactivity as shown by a rapid programmed cell death when transiently overexpressed in Nicotiana benthamiana leaf cells. Therefore, we hypothesized that the mechanisms by which RPS2 and MR5 are activated by AvrRpt2-directly cleavage of RIN4 differ from each other. Further mechanistic analysis of the AvrRpt2-triggered activation of MR5 via cleavage of RIN4 showed that the activation mechanism of MR5 requires a novel property of RIN4 that is not required for activation of RPS2.

Abstract Number: P17-615
Session Type: Poster