Plant and Pathogen Loci Determining Recognition and Cell Death in Arabidopsis Thaliana.

Abstract

Three areas of work are reported. The first involves the identification, molecular mapping and progress towards cloning the RPM1 locus conditioning resistance to strains of Pseudomonas syringae carrying the corresponding avrRpm1 avirulence gene. The second involves the isolation and characterization of mutants expressing cell death phenotypes simulating disease resistance responses. Of the 4 mutants studied as exhibiting lsd (lesion simulating disease resistance response) phenotypes, 2 are being cloned (lsd1 and lsd5) and phenotypic revertants of both have been isolated. The third area involves identification of bacterial genes necessary for delivery of the avrRpm1 signal, particularly 2 classes of P. syringae genes that trigger a specific plant defence response: the avrRpm1 gene, which is also required for virulence on Arabidopsis, and non-hrp cluster genes needed for delivery of specific avrRpm1 function.