Poster: Plant-pathogen interactions

Abs # 527: Functional Analysis of Heat Shock Genes in Compatible Plant-Virus Interactions

Presenter:	Carr, Tyrell , tcarr@iastate.edu
Authors	Carr, Tyrell  (A) (B)  Whitham, Steven A. (A) (B)
Affiliations:	(A): Iowa State University (B): Department of Plant Pathology

Several studies implicate heat shock proteins in various viral processes, including replication, translation, movement and protein folding. Microarray analyses have found that the expression of a variety of heat shock genes including HSP17.6A, HSP23.6, HSP70, HSP83, and HSP101 can be induced by viral infections in Arabidopsis. Virus-regulated expression of heat shock genes was detected in inoculated and systemic leaves and flowers. The expression kinetics of specific heat shock genes in Arabidopsis is differentially regulated in response to viruses. For example, HSP17.6A and HSP101 were induced early in inoculated leaves by the tobamovirus, oilseed rape mosaic virus (ORMV) but not by cucumber mosaic virus (CMV) and turnip mosaic virus (TuMV). HSP17.6A and HSP101 protein are detected in ORMV-infected Arabidopsis plants. In particular, HSP101 mRNA accumulation is closely correlated with protein expression. Expression profiles of heat shock genes were not affected in virus-infected Arabidopsis mutants defective in ethylene, jasmonic acid and salicylic acid signal perception. To test the possibility that HSP101 or HSP17.6A could have a role in viral pathogenesis, ORMV accumulation was quantified in Arabidopsis mutants for HSP101 and HSP17.6A. To further determine the function of heat shock genes in viral pathogenesis, virus-induced gene silencing (VIGS) was used to silence heat shock gene homologues in Nicotiana benthamiana prior to virus challenge. Results from these gene expression and functional studies will be presented.