Functional And Stress Tolerance Analysis Of Rice OsAPX2 Gene

Rice is the important crop in the world, and also is the important model plant. In China, the sown area of rice is about 30% and the yield is about 50%. With the declining in arable land and increasing population, rice production is becoming an important factor for food security. However, when hybrid rice breeding and ultra-high-yield breeding targets were carried out, the rice yield has been a bottleneck in the development stage. Pests and diseases, poor natural environment and other factors also affect the high and stable yield of rice. Therefore, how to ensure high quality varieties in different natural environmental conditions (such as drought, low temperature and salinity and other environmental stress) stable is the current breeders and biologists to attention and it becomes one of the important issues in the world.Our lab takes a T-DNA insert mutant of rice(O.Sativa. L.spp.japonica,var nippobare)which ascorbate peroxidase gene was destructed. APX is the scavenger of H₂O₂. We known that H₂O₂ belongs to reactive oxygen species(ROS) which could use Haber-Weiss reaction to generate high active radical and destroy cell death. So ROS must be eliminated in organism. We are doing more research about OsAPX2 in the foundation of former analysis. The results are followed:1,The phenotype analysis of osapx2 mutant and the contents of H₂O₂We could find that the height of mutant is about 63cm just 1/2 height of wildtype. The leaf of mutant also appears mimic and angle became larger than wildtype. The content of H₂O₂ is higher than wildtype double. We could consider that the destroyed of OsAPX2 caused the H₂O₂ increased. This affected the plants'normal development.2,Acquisition of OsAPX2 overexpression plants and the analysis of OsAPX2 geneWe acquired the construct of OsAPX2 gene expression vector and transferred the OsAPX2 gene into the wildtype plants using Agrobacterium mediated method. In the result, we got many positive plants after identified with PCR. Meanwhile, we analysed the expression of OsAPX2 gene in these positive rice lines and the mRNA level of OsAPX2 gene have been enhanced in different degrees. The phenotype between wildtype and overexpression rice are similar.3,OsAPX2 gene overexpression rice could resist different abiotic stressesWe did the treatment of drought,salinity,low-temperature and high-temperature respectively to OsAPX2 gene overexpression with wildtype control. The result indicated that the influence of H₂O₂ and MDA in overexpression plants is unobvious and the content of proline increased lower than wildtype. At last we analysed their agronomic trait, the seed setting rate were decreased in different stress conditions, but compared with wildtype the OsAPX2 gene overexpression rice is better in the yield. So it demonstrated that OsAPX2 gene overexpression rice enhanced its stress tolerance. This is important to remain rice yield at stress conditions.