Poster: Plant-pathogen interactions

Abs # 539: Functional Analysis of Plant Bacterial Effectors AvrRxv and Y4LO in Tomato

Presenter:	Zakharyevich, Kseniya , ksushaaa@yahoo.com
Authors	Zakharyevich, Kseniya  (A)   Yoshikawa, Masayasu  (A)   Whalen, Maureen  (A)
Affiliations:	(A): San Francisco State University

Xanthomonas axonopodis pv. vesicatoria is the causal agent of bacterial spot disease of tomato plants. AvrRxv is a bacterial effector which plays a role in resistance induction on tomato. Sequence similarity of the AvrRxv gene product with YopJ family members suggested that AvrRxv belongs to a group of cysteine proteases found in various pathogenic bacteria of both plants and animals. We demonstrated that when directly expressed by host cells AvrRxv activity requires the essential catalytic triad found in this group of cysteine proteases by mutational analysis (H180A, C244A, E200A). Neither YopJ nor AvrRxv mutants outside the catalytic triad had resistance-inducing activity. We are currently investigating the effect of the mutations in AvrRxv on its stability. In addition, we are testing the effect on host response of homologue Y4LO from Rhizobium when carried by the Xanthomonas as well as when expressed by the plant.