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POSTERS: Pathogenicity and host specificity

Diversity of Ralstonia solanacearum infecting multiple hosts in Southeast Asia
Taylor Klass - The Ohio State University. John Long- Department of Plant Pathology, The Ohio State University, Tuan Tran- Nanyang Technological University, Caitilyn Allen- University of Wisconsin-Madison, Madeline Hayes- University of Wisconsin-Madison, Kim Hian Seng- iDE Cambodia, Sally Miller-

The soilborne plant pathogen Ralstonia solanacearum causes bacterial wilt of over 200 different plant species, including tomato, potato, eggplant, and peanut. This bacterium is particularly important because of its lethality, wide host range, and global distribution. Additionally, the pathogen forms a heterogenous species complex, meaning resistance breeding and management strategies must be tailored to local strains. Although bacterial wilt is present in Cambodia and Vietnam, little is known about the distribution and diversity of R. solanacearum in these countries. We therefore isolated Cambodian and Vietnamese R. solanacearum strains from various hosts, including tomato and potato, and performed Koch’s postulates to confirm host range. Notably, we isolated R. solanacearum from tomato (Solanum lycopersicum), long bean (Vigna unguiculata subsp. sesquipedalis), and bitter gourd (Momordica charantia) in a single field plot from a mixed cropping system in Cambodia. Long bean and bitter gourd were not previously known hosts for R. solanacearum in these countries. Our results identify the diversity of R. solanacearum within a geographic region and the continually expanding host range of this pathogen. Not only do these results fill a knowledge gap on pathogen diversity, they also provide a foundation for development of varieties specifically resistant to bacterial wilt for Southeast Asian farmers.