The Function Analysis Of Glutaredoxin Gene OsGRX20in Rice

Plants can produce a large amount of reactive oxygen species (ROS) when they are under various stresses. However, a balanced amount of ROS is crucial for many metabolic processes of plant cells. Once the ROS is accumulated, thereby inevitably causing oxidative stress. Plants have developed a set of complex mechanism for regulating ROS in the process of the long-term evolution. Glutaredoxins (GRXs) are a kind of enzyme that can help to scavenge ROS. GRXs are a class of glutathione-dependent oxidoreductases involved in a variety of cellular processes. In the recent years, a few of GRXs genes in different plants were cloned and studied. In our previous study, a protein OsGRX20which was upregulated after inoculated with Zhel73in resistant variety SH5was isolated by using the proteomic analyses. The cDNA and DNA of OsGRX20gene were cloned. Here, the function of OsGRX20gene was studied. The results are as following:(1) The sequence of OsGRX20gene analysis showed that the active site was CPFC, with a glutathione binding site near it, it belonged to typical sub-types I of GRXs;(2) Real-time quantitative PCR analysis of the expression of OsGRX20gene under biotic (infection of bacterial leaf blight pathogen) and abiotic (high salt, drought, low temperature and oxidative stress) stresses of rice variety SH5; The result showed that OsGRX20gene was induced by different adversity stresses;(3) OsGRX20gene was mainly expressed in the leaf, very low or undetectable in the stem and root. The promoter of OsGRX20gene was cloned and was fused with GUS reporter gene to construct a plant expression vector. The result of histochemical allocation was the same as the gene expression in rice organs;(4) The over-expression vector and RNAi vector were constructed, and then, were transferred into rice variety8411and SH5, respectively. The transgenic lines and its wild-type were treated by biotic and abiotic stresses. The average lesion length of over-expression and RNAi lines did not change insignificantly compared with their wild-type. However, the survival rate in RNAi lines was lower than wild-type under salt and methylviologen treatment. The penotypes under drought treatment did not show abvious changes between RNAi lines and wild-type. After treatment with different concentration of NaCl, the germination rate of RNAi lines was lower than wild-type at the certain concentration of NaCl.