Fine-scale Mapping Of The Bel Gene For Sensitivity To Bentazon In Rice (Oryza Sativa L.)

Contamination of hybrid seed is one of the major factors affecting the yields of hybrid rice. To breed benatazon sensitive male sterility lines utilizing the gene bel for sensitivity to herbicide benatazon and use them in hybrid seed production can helps to prevent the contamination caused by selfing of male sterility lines effectively. It is of great significance to make a fine-scale mapping of bel gene for positional cloning of bel gene and breeding of benatazon sensitive male sterility lines with bel gene by marker-assisted selection.The bel gene was first-pass mapped within a 1.9 cM (about 500kb) region on rice chromosome 3 between the SSR markers RM416 and RM3867. A fine-scale mapping of bel gene by SNPs was then performed based on the first-pass mapping. It was showed that the bel gene was located within the region of 92kb between two SNP markers (SNP158 and SNP138), and four other SNPs were observed to cosegregate with the gene. The results indicated that a deletion of a single nucleotide in the coding region of cytochrome P450 hydroxylase geneon rice chromosome 3 might be the direct cause of the sensitivity to bentazon in rice.A new strategy for gene mapping which combined SSR with SNPs markers was suggested, and the significane in gene mapping and discovery was discussed.