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Poster: Diseases of Plants: Disease Detection & Diagnosis


A computer program for fast and easy typing of Ralstonia solanacearum species complex strains into genospecies and sequevars 1&2
M. STULBERG (1), Q. Huang (2) (1) FNPRU, USDA/ARS & ORISE, U.S.A.; (2) FNPRU, USDA/ARS, U.S.A.

The phytopathogen Ralstonia solanacearum is a species complex that contains race 3 biovar 2 strains belonging to phylotype IIB sequevars 1 and 2 that are quarantined or select agent pathogens. Recently, the R. solanacearum species complex strains have been reclassified into three genospecies: R. solanacearum, R. pseudosolanacearum and R. sygyzii. An unidentified R. solanacearum strain is considered a select agent in the US until proven to be a non-race 3 biovar 2 (non-phylotype IIB sequevars 1&2). We wrote a computer program that analyzes a minimum 400-bp user-input egl sequence from a R. solanacearum species complex strain for egl homology and SNP content to determine 1) whether it belongs to the R. solanacearum species complex, 2) if so, to which genospecies, and 3) whether it is of the sequevar type (sequevars 1 and 2) associated with the select agent/quarantined R. solanacearum strain. The program correctly typed all 371 tested egl sequences with known sequevars. It also successfully typed 25 R. solanacearum strains with no prior sequevar information, as well as 4 strains from infected plant samples, using their partial egl sequences amplified and sequenced with primers designed in this study. The Ralstonia solanacearum typing program does not require expertise or specific knowledge to use, gives results in seconds, and provides data interpretation for the user regarding the genospecies and sequevar 1 or 2 status of the strain in question.