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Poster: Biology & Disease Mgmt: Genetics of Resistance


Quantitative resistance loci identified for the bacterial blight causative agent, Xanthomonas oryzae pv. oryzae
A. HUERTA (1), E. Delorean (2), A. Bossa-Castro (2), C. Raghavan (3), R. Corral (2), V. Verdier3 (4), H. Leung (5), J. Leach (2) (1) Colorado State University, U.S.A.; (2) Department of Bioagricultural Sciences and Pest Management, Colorado State Universi

Any factor that limits or reduces attainable agricultural yield, including plant disease, will impact global food security. Xanthomonas oryzae pv. oryzae (Xoo) causes the most important bacterial disease of rice, bacterial blight (BB). Deployment of resistance varieties is the gold standard for managing plant diseases, having the strongest impact with minimal environmental effects and cost. However, resistance breeding depends on harnessing genetic diversity in available germplasm for identification of effective and durable disease resistance. To identify durable resistance, we screened 330 advanced inbred lines (AILs) from the indica Multi-Parent Advanced Generation Inter-Cross (MAGIC) rice population for resistance to Xoo strains, PXO99A and PXO99A harboring TAL-effector TAL7b (+TAL7b). TAL7b, a virulence factor for Xoo, allowed us to test the hypothesis that resistance targeted to important virulence factors will be more durable when deployed. Transgressive segregation for resistance was observed to both PXO99A and PXO99A +TAL7b, suggesting the presence of resistance QTL for BB. Genome-wide association (GWA) and interval mapping analysis, revealed 13 disease resistance QTL, six specific to PXO99 +TAL7B and seven to PXO99A. Future exploitation of the MAGIC AILs and screening a new subset of lines selected based on the knowledge acquired from this study will refine the resistance loci, and help elucidate the molecular basis for the resistance phenotypes identified.