Poster: Plant-pathogen interactions

Abs # 561: Early chlorosis factor in bacterial spot disease of tomato

Presenter:	Franklin, Darleen , dbenbasil@hotmail.com
Authors	Franklin, Darleen  (A)   Posada, Jessica  (A)   Whalen, Maureen  (A)
Affiliations:	(A): San Francisco State University, Dept of Biology
Web Site:	http://darleen@sfsu.edu

One of the early symptoms of bacterial spot disease in tomato is a visible chlorosis. The gene in the bacterial pathogen Xanthomonas that triggers this response is the early chlorosis factor gene (ecf). Our goal is to understand the molecular mechanisms of chlorosis induction in tomato. Since ecf is not similar to any gene with known function, the DNA flanking ecf was sequenced. ABC transporter components, outer membrane proteins and L-sorbosone dehydrogenase were identified; however, the correlation of these functions with chlorosis is not clear. Genomic rearrangements at the ecf locus were apparent in other xanthomonads. The chlorosis function of ecf requires the type III translocation system in Xanthomonas. We addressed the possibility that the ecf gene product is translocated into the host cell cytoplasm by analyzing host responses to Agrobacterium-mediated, in planta transient expression. The ecf gene product may directly function in the host cell to induce chlorosis under certain plant growth conditions. Studies are underway to learn more about in planta expression and function.