Genotypic dependent effect of exogenous glutathione on Cd-induced changes in proteins, ultrastructure and antioxidant defense enzymes in rice seedlings.

Greenhouse hydroponic experiments were conducted using Cd-sensitive (cv. Xiushui63) and tolerant (Bing97252) rice genotypes to evaluate how different genotypes responded to Cd toxicity in presence of glutathione (GSH). Results showed that GSH alleviates Cd-toxicity, ameliorates Cd-induced damages on leaf/root ultrastructures. Nine proteins in roots were identified, using 2-DE coupled with mass spectrometry, whose expression were down-regulated in Xiushui63, up-regulated/unchanged in Bing97252 by Cd; coinstantaneously enhanced/unchanged in Cd+GSH over Cd alone treatment in both genotypes. They are l-ascorbate peroxidase, putative short-chain dehydrogenase/reductase, Glycolipid transfer protein, elongation factor, Os04g0652700, carbonic anhydrase, Os08g0374000, chitinase, and putative disease resistance response protein. Eight proteins in leaves with expression of increase in Bing97252 but down-regulate/unchange in Xiushui63, categorized as four groups of their functions: carbon metabolism, TCA cycle, photorespiration and RNA processing. Furthermore, we identified eight proteins with repressed expression in Cd-treated and up-regulated in Cd+GSH-treated rice leaves of Xiushui63.