Selenate mitigates arsenite toxicity in rice (Oryza sativa L) by reducing arsenic uptake and ameliorates amino acid content and thiol metabolism

Arsenic (As) is a toxic element with the potential to cause health effects in humans. Besides rice is a source of both amino acids (AAs) and mineral nutrients, it is undesired source of As for billions of people consuming rice as the staple food. Selenium (Se) is an essential metalloid, which can regulate As toxicity by strengthening antioxidant potential. The present study was designed to investigate As-III stress mitigating effect of Se-VI in rice. The level of As, thiolic ligands and AAs was analyzed in rice seedlings after exposure to As-III/Se-VI alone and As-III+Se-VI treatments. Selenate supplementation (As-III 25 mu M+Se-VI 25 mu M) decreased total As accumulation in both root and shoot (179 & 144%) as compared to As-III alone treatment The As-III+Se-VI treatment also induced the levels of non-protein thiols (NPTs), glutathione (GSH) and phytochelatins (PCs) as compared to As-III alone treatment and also modulated the activity of enzymes of thiol metabolism. The content of amino acids (AAs) was significantly altered with Se-VI supplementation. Importantly, essential amino acids.(EAAs) were enhanced in As-III+Se-VI treatment as compared to As-III alone treatment In contrast, stress related non-essential amino acids (NEAAs) like GAGA, Glu, Gly, Pro and Cys showed enhanced levels in As-III alone treatment In conclusion, rice supplemented with Se-VI tolerated As toxicity with reduced As accumulation and increased the nutrition quality by increasing EAAs. (C) 2016 Published by Elsevier Inc.