Poster: Plant Pathogen/Symbiont Interactions

Abs # 742: The Arabidopsis COPINE 1 gene is pathogen regulated

Presenter:	McNellis, Timothy , mcnellis@psu.edu
Authors	McNellis, Timothy  (A)   Jambunathan, Niranjani  (A)
Affiliations:	(A): Penn State University

The copines are a widely distributed class of calcium-dependent, phospholipid binding proteins of undetermined biological function. Mutation of the Arabidopsis COPINE 1 gene (CPN1) causes a humidity-sensitive lesion mimic phenotype with increased resistance to a bacterial and an oomyceteous pathogen, constitutive pathogenesis-related (PR) gene expression, and an accelerated hypersensitive cell death defense response (HR). Here, we show that the disease resistance phenotype of the cpn1-1 mutant was also temperature sensitive; demonstrate increased CPN1 gene transcript accumulation in wild-type plants under low humidity conditions; and present a detailed analysis of CPN1 gene transcript accumulation in response to bacterial pathogens. In wild-type plants, CPN1 transcript accumulation was rapidly, locally, and transiently induced by both avirulent and virulent strains of Pseudomonas syringae pv. tomato (P.s.t.) bacteria. However, the induction of CPN1 transcript accumulation by avirulent bacteria was much faster and stronger than that induced by virulent bacteria. Bacterial induction of CPN1 transcript accumulation was dependent on a functional type III bacterial protein secretion system. In planta expression of the avrRpt2 avirulence gene was sufficient to trigger rapid CPN1 transcript accumulation. CPN1 transcript accumulation was induced by salicylic acid (SA) treatment but was not observed during lesion formation in the lesion mimic mutants lsd1 and lsd5. These results provide clear evidence for the involvement of CPN1 in plant disease resistance responses and indicate that CPN1 may represent a link between plant disease resistance and plant adaptation to low humidity and low temperature conditions.