Project Number: 1931-22000-008-00
Project Type: Appropriated

Start Date: Mar 20, 2007
End Date: Mar 19, 2012

Objective:
The objective of this project is to develop novel, biologically-based disease-control strategies for temperate fruit crops in order to reduce the use of chemical pesticides. This will be done by identifying microbial antagonists that are effective against latent and wound-induced infections of stone fruit, determining the genetic factors that make the brown rot pathogen so virulent by comparing host response to pathogenic and non-pathogenic organisms, and determining the role of fungal polygalacturonases as a virulence factor for postharvest infections of pear and peach.

Approach:
The project will utilize a broad range of approaches to develop new biologically-based methods of postharvest disease control. Naturally-occurring yeasts and bacteria will be isolated from stone fruit and screened for activity against latent and wound-induced infections of stone fruit caused by the brown-rot organism, Monolinia fructicola. As part of the evaluation, select microbes will be tested for their ability to degrade melanized fungal structures such as appressoria using a model membrane system. Subtractive-suppressive hybridization of cDNA libraries will also be utilized to better understand the genetic basis of resistance mechanisms in stone fruit. This will be done by comparing host response at different developmental stages to both pathogens and non-pathogens. Lastly, the role of fungal polygalacturonases (PGs) as a virulence factor will be studied by utilizing recombinant antibody technology. The effect of the recombinant antibodies on conidial germination and the infection process will be evaluated.