Identification of a rice locus conferring broad spectrum disease resistance to bacterial pathogens
A. BOSSA-CASTRO (1), C. Raghavan (2), C. Tekete (3), E. Delorean (1), A. Dereeper (4), K. Dagno (5), O. Koita (3), G. Mosquera (6), H. Leung (2), V. Verdier (4), J. Leach (1) (1) Colorado State University, U.S.A.; (2) International Rice Research Institute (IRRI), Philippines; (3) Université des Sciences Techniques et Technologiques, Faculté des Sciences et Techniques, LBMA, Mali; (4) IRD, Cirad, Univ. Montpellier, Interactions Plantes Microorganismes Environnement, France; (5) Institute of Rural Economy, Plant Protection, Mali; (6) International Center for Tropical Agriculture (CIAT), Colombia

Bacterial blight (BB) and bacterial leaf streak (BLS) are caused by Xanthomonas oryzae pv. oryzae (Xoo) and X. oryzae pv. oryzicola (Xoc), respectively. These diseases of rice are widespread in Africa and Asia, and cause considerable losses. In Africa, effective BB or BLS resistance is largely absent in the rice germplasm currently used. Our goal is to identify novel, broad-spectrum resistance sources to control BB and BLS in rice, using a new mapping resource, a Multi-parent Advanced Generation Inter-Cross (MAGIC) population. The advantage of MAGIC populations is the increased level of recombination and higher resolution to detect quantitative trait loci (QTL). Two subsets of the MAGIC were randomly selected at the fourth (S4) and eighth (S8) stage of selfing. Founders and both subsets were genotyped by sequencing and phenotyped in the greenhouse using two African Xoo and Xoc isolates each. In parallel, the S8 subset was phenotyped in the field in Mali with nine Xoc and ten Xoo isolates from different genetic backgrounds to validate our results.  Using genome-wide association and interval mapping analysis, we identified novel disease resistance QTL, including one that is effective against both Xoo and Xoc.  Characterization of this potential source of broad spectrum resistance is in progress. Because the MAGIC population was derived from elite cultivars, ultimate use of resistance sources in breeding programs will be expedited.

Abstract Number: P17-498
Session Type: Poster