Department of Plant Sciences

Both species of arsenic (As), arsenate and arsenite are highly toxic to plants. Arsenic contamination is a major problem in Southeast Asia particularly in Bangladesh and West Bengal. In these countries, As-contaminated groundwater is widely used for irrigating rice in dry season that results in elevated As accumulation in soils and in rice grain and straw. So it is important for understanding the accumulation and transport mechanisms of arsenic in rice. We monitored increased arsenic content in rice grain and straw when rice plants were irrigated with heavily As-contaminated shallow tube well water. However, the arsenic content was significantly decreased both in rice grain and straw when the plants were supplied with low As-contaminated water from pond. These results indicate that As accumulation in rice is dependent on its external supply. Now it is urgent to investigate how the As is transported to rice plants. Arsenite transporter in plants has recently been reported. It is also reported in Arabidopsis that arsenate is taken by plants through phosphate transporters. However, it is not well documented in rice plants. There are 13 putative rice phosphate transporters (OsPTs). Based on phylogenetic analysis the OsPTs can be classified into three groups. Some of the members of OsPT family might be involved in arsenate transport in rice. Currently, we are investigating the possible involvement of OsPTs in arsenate transport in rice.