| In the rice, Bacterial blight, caused by Xanthomonas oryzae pv. Oryzae, and blast caused by Magnaporthe grisea, were the two most devastating diseases worldwide. These diseases reduces rice yield by 10%-40%. It is well known that breeding resistant varieties in rice is the most effective and economical method to control these diseases. Until now, more than 60 rice blast resistance genes and 30 rice bacterial blight resistance genes have been identified.Here we show that the gene underlying the major quantitative trait locus (QTL), rbr2, for blast resistance in rice variety Minghui 63 is a new blast resistance gene by fining mapping, sequence analysis, and expression analysis of rbr2. The rbr2 encodes a nucleotide-binding site (NBS)-leucine-rich repeat (LRR) type protein and is an allele of blast resistance gene Pib. The amino acid differences of the predicted encoding products of rbr2 and Pib occur mainly in LRR domain, which may be the major cause that the resistance spectrums mediated by the two genes are different. The rbr2, as a new resistance gene, can be used in rice breeding programs.Present study was focused, to further determine the resistance of Xa25(t), for bacteria blight resistance in rice variety Minghui 63 and to construct the fine genetic map for this particular gene. Xa25(t) is located beteen two SSR markers, RM511 and RM28107, on chromsome 12 of rice genome. This information can be further used in rice molecular-assisted selection breeding. Further this gene can be cloned to confirm the exact function of this gene in the rice plant system. |
