Project Number: 1245-32420-005-02
Project Type: Reimbursable

Start Date: Jun 17, 2011
End Date: May 31, 2014

Objective:
1. Concurrently evaluate the persistence of three foodborne pathogens (E. coli O157:H7, Salmonella, and Norovirus) on foliar surfaces of plants (lettuce and spinach), under the same conditions to facilitate a direct comparison of the survival characteristics of these organisms in the phyllosphere. 2. Investigate plant defense pathways during attachment and internalization of E. coli O157:H7, Salmonella and noroviruses. Determine if plants respond to these human pathogens using one or more plant-specific defense strategies. 3. Evaluate the metabolic pathways used by pathogenic bacteria to attach to plants, specifically using a novel approach to identify the major proteins of pathogenic bacteria using proteomics.

Approach:
ARS will acquire the basic knowledge of how E. coli O157:H7, Salmonella, and norovirus survive under the exact same growing conditions, and to use culture and molecular methods to evaluate the persistence of these pathogens on foliar surfaces and plant responses to these pathogens. This information will be used by both ARS and the Cooperator to jointly develop a comprehensive understanding the interaction of bacterial and viral pathogens with leafy green crops and possibly develop antimicrobials or Good Agricultural Practices that can limit the contamination of produce. The Cooperator will specifically evaluate the infectivity of norovirus inoculated on leafy greens, and will determine methods using quantitative real time PCR (qPCR) targets to measure the expression of plant defense responses to pathogens.