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Novel sources of disease resistance in pepper against bacterial spot xanthomonads

Neha Potnis: Department of Entomology and Plant Pathology, Auburn University

<div>Bacterial spot <em>Xanthomonas</em> species cause significant disease outbreaks on tomato and pepper in the tropical and subtropical regions throughout the world. Changing pathogen population structure and the geographical distribution have significantly impacted the durability of single/ combinatorial resistance genes currently employed in pepper cultivars in the U.S. These findings reinforce the importance of identifying novel candidates for bacterial spot disease resistance. Our studies involving extensive phenotyping on diverse core germplasm of pepper against <em>Xanthomonas gardneri</em> followed by genotyping-by-sequencing and association analyses yielded highly significant SNPs associated with bacterial spot disease phenotypes. We further screened the pepper genome and identified genes associated with the significant SNPs. Based on annotations, the candidate genes have been found to encode proteins involved in hormone signaling, developmental processes, disease resistance against specific pathogens as well as some involved in basal resistance against multiple viral, fungal and bacterial pathogens. Screening the efficacy of resistant genotypes against different pepper pathogens identified several promising genotypes that impart resistance/tolerance against multiple pathogens of pepper. Potential resistance loci as well as genotypes carrying these loci identified in this study will be employed as a part of resistance gene pyramiding effort against the changing pathogen population structure.</div>