Interactive effects of nitric oxide and glutathionein mitigating copper toxicity of rice(Oryza sativaL.) seedlings

摘要

Ntric oxide (NO) and glutathione (GSH) are 2 vital components of the antioxidant system that play diverse roles inplant responses to abiotic stresses. Recently, we have reported that exogenous supply of both these molecules reducedcopper (Cu) toxicityin rice seedlings. Individual as well as co-treatment of sodium nitroprusside (SNP: a NO donor) andGSH with Cu significantly mitigated the adverse effects of Cu, evident in the reduced level of oxidative markers such asH2O2, superoxide (O2), malondialdehyde (MDA), and proline (Pro). GSH content and most of the antioxidative andglyoxalase enzymes were up-regulated upon Cu stress, indicating their responses were co-related with the level ofstress. Our results indicated that direct ROS scavenging, reducedCu uptake, and the balanced antioxidative andglyoxalase systems, at least in part, successfully executed NO- and GSH-mediated alleviation of Cu toxicity in riceseedlings. In addition, the combined effect of adding SNP and GSH together was more efficientthan the effect ofadding them individually. Here, we are speculating that 1) GSH and Pro could be used as potential markers for copperstress, and 2) adding SNP and GSH might produceS-nitrosoglutathione (GSNO) which could be a source of bioactiveNO and may affect many regulatory processes involved in Cu-stress tolerance. We further note that the combined effectof adding SNP and GSH was pronounced in inhibiting the uptake and translocation of Cu in rice seedlings.