Poster: Plant-pathogen interactions

Abs # 570: Characterization of Arabidopsis mutants insensitive to a type III effector

Presenter:	Chintamanani, Satya P, satya@ksu.edu
Authors	Chintamanani, Satya P (A)   He, Ping  (B)   Baker, Douglas  (A)   Tang, Xiaoyan  (A)   Zhou, Jian-Min  (A)
Affiliations:	(A): Kansas state university (B): Harvard Medical School

Type III effectors of Pseudomonas syringae play a key role in its ability to cause diseases on host plants by modulating host cellular activities, but their function in the plant cell remains largely unknown. We have shown previously that the expression of RAP2.6, an ERF (Ethylene Response Factor) family transcription factor gene, is induced by several P. syringae effectors, including AvrB, independent of disease resistance gene function. RAP2.6 expression appears to be associated with bacterial virulence and plant susceptibility to P. syringae. To further understand plant cellular activities modulated by a bacterial effector, we have screened EMS mutagenized RAP2.6-LUC transgenic plants for the reduced responsiveness to AvrB (rrb) carried by P. syringae. In total, we isolated eight confirmed rrb mutants. The rrb mutants appeared to be affected in distinct signaling components because the mutant genes mapped to different chromosomal positions. To broadly characterize the regulatory pathways involved, we are systematically examining by microarray analysis gene expression profiles for all the mutants after inoculation with the bacterium carrying avrB. In addition, we are investigating lipid profiles in the rrb mutants, because lipid-derived secondary messengers play an important role in defense signal transduction. The results, together with our effort to isolate the RRB genes, will be presented.