exhibits complex genetic resistance to pv. .

() is the causal agent of bacterial speck disease in tomatoes. The gene cluster from was introgressed into several modern tomato cultivars and provided protection against race 0 strains for many decades. However, virulent race 1 strains that evade -mediated immunity now predominate in tomato-growing regions worldwide. Here we report the identification of resistance to a race 1 strain (19) in the wild tomato accession LA1589 (hereafter LA1589), using our rapid high-throughput seedling screen. LA1589 supports less bacterial growth than cultivars, and does not exhibit a hypersensitive response to 19. We tested an existing set of 87 Inbred Backcross Lines (IBLs) derived from a cross between susceptible E-6203 and LA1589 for resistance to 19. Using single-marker analysis, we identified three genomic regions associated with resistance. Bacterial growth assays on IBLs confirmed that these regions contribute to resistance . We also mapped candidate genes associated with resistance in a cross between the var. cultivar Heinz BG-1706 and LA1589. By comparing candidates from the two mapping approaches, we were able to identify 3 QTL and 5 candidate genes in LA1589 for a role in resistance to 19. This work will assist in molecular marker-assisted breeding to protect tomato from bacterial speck disease.