Genotypic difference in temporal variation of arsenic accumulation and expression of silicon efflux transporter (LSi2) gene in the field grown rice

Rice-straw accumulated significantly higher amount of arsenic than grain but linear correlation did not exist among straw and grain accumulation. A popular cultivar, IR64 accumulated majority of grain arsenic in the husk, rather than brown rice, both at kharif and boro season. Till two weeks after fertilization (dough stage) arsenic accumulation in spikelet remains same for all the eight genotypes. Variation of total arsenic in grain of eight rice genotypes started during dough stage to maturity. Expression of arsenite efflux transporter, LSi2, in root and stem was not correlated with arsenic accumulation at brown rice but expression in grain showed stronger correlation (r=0.87) with accumulation in husk among these genotypes.