Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/6/1996
Publication Date: N/A
Interpretive Summary: Bacterial leaf blight is a major disease of cultivated rice. The Xa21 gene, which confers resistance to this disease, is well known in a wild relative of rice. However, the assay for resistance is difficult, thus the gene cannot be easily incorporated into rice cultivars. We identified six DNA markers that flank the resistance gene. These markers were modified so othat their method of detection was simple and inexpensive. Because these markers flank the resistance gene and are easy to use, plant breeders can now follow the markers through genetic crosses and move the resistance gene into cultivated rice by conventional breeding methods.
Technical Abstract: Six molecular markers were mapped to a 7.4 cM region of rice chromosome 11 containing the Xa21 gene, which confers resistance to the pathogen Xanthomonas oryzae pv. oryzae. Three markers, RG103, 248 and 818 cosegregated with Xa21 in a population of 1141 plants. Multiple copies of all marker loci were present within the region that was introgressed from Oryza longistaminata into O. sativa. The marker loci were cloned and primers were designed that defined sequence-tagged sites. Physical mapping of the three tightly linked central markers revealed that RG103, the marker that hybridizes to the Xa21 gene, resides on a separate DNA fragment from the other two markers.