Arsenic Stress Responsive Amino Acids in Rice Plant

Paddy fields in South and South-East Asia are being irrigated with arsenic contaminated groundwater accumulated over ages from Himalayan minerals. It is posing a health hazard to millions dependent on rice as subsistence diet and also to sustainable agriculture in affected areas. Rice accumulates 10 fold higher arsenic than wheat and other cereals and is said to be a neglected cancer risk. Arsenic toxicity affects concentration of other macro and micronutrients in plant tissues either through direct competition with their uptake or due to disturbance to nutrient metabolism consequently leading to amino acid loss. Metal induced production of ROS may also suppress the whole amino acid profile, the building blocks of proteins. Amino acids can be peroxidized by free radicals turning them into second toxic messengers in cells and tissues consequently, even resulting in the oxidation and depletion of vital antioxidants in vivo. On the other hand, histidine, proline, cysteine, proline, cysteine and glycine along with other amino acids are known to be induced significantly upon heavy metal exposure. Therefore, amino acid metabolism in plant under stress is important to understand.