This proposal assembles a combination of biochemical, immunological, molecular and genetic approaches to elucidate the plant response to Erwinia using potato as a model. The natural resistance of wild potato species and their hybrids with cultivated potato will provide a model to distinguish the defense genes and proteins associated with resistance to this pathogen. Definition of a category of relevant target genes will allow the use of the powerful transgenic-based approaches to obtain a set of signal transduction mutants and consequently clone the corresponding genes encoding regulatory proteins controlling plant defense responses. These mutants will define essential components in plant defense which can be subsequently utilized for engineering disease resistance. The proposed studies are likely to identify new disease resistance strategies for example by overexpressing signal components or relevant target genes in transgenic crop plants. The nonspecific nature of plant-Erwinia interaction suggests that resistance strategies developed to control this pathogen are likely to be effective against a broad range of different plant pathogens.
Molecular breeding for disease resistance is likely to be the most effective way to generate disease resistant crop plants. Manipulation of the target genes implicated in induced resistance to pathogens or the signal transduction pathways controlling expression of such defense-related genes provide the most promising targets for development of this new generation of resistance strategies. Realization of these strategies will, however require a considerable investment in basic research on the molecular mechanisms of plant-pathogen interaction, characterization of signals and signal transduction pathways involved that lead to a specific defense response. This proposal will systematically address these questions by dissecting a signal transduction pathway leading to induced defense response to a nonspecific bacterial pathogen Erwinia carotovora. Erwinia, the causative agent of soft-rot disease provides an excellent model for such studies due to the extensive knowledge accumulated on the pathology, biochemistry and molecular genetics of this pathogen. The nonspecific nature of the Erwinia-plant interaction allows a detailed study of the basic induced defense responses in plants without the added complication of race-cultivar specific interactions. This proposal will examine the nature of plant defense-related target genes triggered by Erwinia infection or by elicitors produced by this pathogen, characterize components involved in the signal pathways that control expression of these genes and elucidate the molecular interactions that lead to recognition of this pathogen by the plant host. Modulation of defense gene activity by Erwinia or triggering of virulence genes by the host will also be essential components in understanding this interaction.
Funding SchemeCSC - Cost-sharing contracts
DD2 5DA Dundee