Abstract
Drought and salt stresses, as major environmental abiotic stresses in agricultural worldwide, affect plant growth and crop productivity and quality. The development of crops with higher drought and salt tolerance is therefore highly desirable. Here, we reported the isolation and biological function and molecular characterization of a novel maspardin gene, OsMas, from rice cultivar Yangjing 805 (Oryza sativa L.). The expression levels of OsMas were up-regulated under mannitol, PEG6000, NaCl and ABA treatments in rice. Heterologous expression of OsMas enhanced salt and drought tolerance in Escherichia coli and Arabidopsis. Moreover, the OsMas gene was introduced into rice cultivar Zhonghua 11 (wild-type, WT) and the OsMas-overexpression (OsMas-OE) rice plants exhibited significantly enhanced salt and drought tolerance, while the OsMas-interference (OsMas-RNAi) rice plants exhibited decreased tolerance to salt and drought stresses, compared with WT plants. The OsMas-OE plants exhibited enhanced hypersensitive, while the OsMas-RNAi plants showed less sensitive to exogenous ABA treatment at both germination and post-germination stages. The content of ABA, proline and K+ and the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and photosynthesis were significantly increased, while the content of malonaldehyde (MDA), hydrogen peroxide (H2O2), superoxide anion radical (O2-) and Na+ were significantly decreased in OsMas-OE plants compared with OsMas-RNAi and WT plants. Overexpression of OsMas up-regulated the genes involved in ABA biosynthesis and signaling pathways, proline biosynthesis pathway, ROS-scavenging system, photosynthesis and ion transport pathways under salt and drought stresses. Collectively, our results indicate that the OsMas gene functions in improving salt and drought tolerance in rice, which may serve as a candidate gene for use in enhancing the resistance to abiotic stresses in crops.