Cloning Of The Red Rice Peroxidase Family Gene OsPrx3 And Characterization Its Protein Function

The potential of crop endogenous protein or enzyme molecules in benefiting human health deserves to be explored in depth.Peroxiredoxins（Prxs）,a member of the peroxidase family,are effective against stresses such as oxidative stress,and the function of homologous genes of this family in red rice is unknown,constraining the discovery of their potentially important value.In this study,we used red rice as material,cloned its genome encoding a peroxiredoxin family gene Os Prx3,identified Os Prx3 in vitro enzyme activity,and used the model animal,Caenorhabditis elegans（C.elegans）,as a vector to investigate its function in resisting oxidative stress and aging.The main findings are as follows:1.The Os Prx3 gene of red rice was successfully cloned.Relative to roots,Os Prx3 was expressed at higher levels in leaves and stems of red rice;Os Prx3expression at seedling stage increased with plant seedling age;and,Os Prx3 gene was induced by external stress factors,H₂O₂（50 m M）,high temperature（42°C,45°C）and UV（90μW/cm~2）could increase its expression.2.The Os Prx3 gene overexpression plant transformation vector was successfully constructed and positive strains of transformed Arabidopsis were obtained.Moreover,high expression of Os Prx3 gene significantly enhanced the ability of Arabidopsis to tolerate 10 m M H₂O₂oxidation compared with wild type.3.Efficient isolation and purification of Os Prx3 protein was achieved by constructing an engineered prokaryotic expression strain.The Os Prx3 protein was found to have free radical scavenging,antioxidant,and DNA protective activities in vitro.The only conserved cysteine residue of Os Prx3 protein is the key site for its in vitro activity.4.Os Prx3 protein had a positive effect on the resistance to oxidation and aging in N2 C.elegans.Compared with the control group,C.elegans fed Os Prx3 protein showed enhanced H₂O₂tolerance,reduced ROS levels,decreased fat content and lipofuscin accumulation;and significantly higher transcript expression levels of related antioxidant pathway regulatory genes（SOD-3,SEK-1,MEV-1,GSC-1,ISP-1,SKN-1,CTL-1）in C.elegans.In conclusion,the expression of Os Prx3 in red rice responds to environmental stress and has the function of enhancing plant antioxidant.Os Prx3 has high in vitro enzymatic activity,it can enhance the ability of animals to resist aging and oxidative stress based on its molecular antioxidant properties.Moreover,the results of the study also provide a basis for promoting the development and application of important protein or enzyme molecular resources in red rice.