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Poster: Molecular & Cellular Plant-Microbe Interactions: MPMI


Global regulatory changes allow for the increased growth of Salmonella in soft rotted tomatoes
A. GEORGE (1), A. George (2) (1) University of Florida, U.S.A.; (2) University of Florida, U.S.A.

While little is known about the mechanisms that allow Salmonella to multiply in tomatoes, even less is understood about how interactions of this human pathogen with phytobacteria contribute to its survival in alternate hosts such as plants. It is now known that bacterial soft rot contributes to an increased fitness of Salmonella enterica sv. Typhimurium in tomato fruits. The goal of this research is to understand the underlying mechanisms involved in this phenomenon. The hypothesis is that a change in the tomato environment caused by Pectobacterium provides an overall benefit for Salmonella. In order to determine the full complement of functions that may be vital for the success of Salmonella in soft rots, we employed high throughput transposon sequencing (TN-seq). Libraries of mutants made via transposon mutagenesis were seeded into tomatoes inoculated with fully virulent Pectobaterium, less virulent Pectobacterium, and no Pectobacterium. As a result, pathways involved in nitrogen metabolism, motility, and other regulatory pathways have been identified as potentially playing a role in these interactions. Deletion mutants of genes identified by the TN-seq were then constructed via Wanner-Datsenko mutagenesis for individual testing in tomatoes. These individual mutations have confirmed the results of the TN-seq. We conclude that a variety of metabolic changes do in fact contribute to the increased growth of Salmonella in tomatoes.