Characterization of a low Si mutant and molecular mapping of responsible gene in rice

Abstract

Rice is a typical Si accumulating plant, however, the mechanism responsible for the high Si uptake by the roots is poorly understood. To understand the molecular mechanism of Si uptake, a rice mutant having low Si content has been isolated (Ma et al 2002). In the present study, further characterization of this mutant was undertaken. The concentration of Si in the xylem sap was much higher in the WT than in the mutant, but that in the root symplastic solution was similar between WT and the mutant. These results suggest that this mutant is defective in loading Si into xylem rather than Si uptake itself. To map the responsible gene, a bulked segregant analysis was performed by using both microsatellite and EST-PCR markers. As a result, the gene was mapped to the chromosome 2. Fine mapping of this gene is being undertaken.