Preliminary Study On The Function Of The Rice OsMOS1 And OsCHR5 Genes In Reproductive Development And Stress Tolerance

Rice（Oryza sativa）is one of the most important food crops in the world.Cloning rice regulatory genes of development and stress tolerance and studying their mechanism are of great significance for breeding high-yield and stress-resistant rice varieties.Studies in Arabidopsis（Arabidopsis thaliana）have shown that MOS1（MODIFIER OF snc1,1）and CHR5 {Chromatin Remodeling 5)both play an important role in the regulation of reproductive development and stress tolerance.This study finds that the Arabidopsis MOSI homologous gene OsMOSl plays an important role in the regulation of seed setting,flowering and cold tolerance;the CHR5 homologous gene OsCHR5 in rice plays an important role in the development of rice gametophyte development,flowering and disease resistance effect.Below are key research findings:1.This study finds that the seed set rate of the Osmosl mutant decreased significantly compared with the wild type,and the mutants had various developmental defects in the pistils and stamens.Under long-day conditions,the Osmosl mutants showed a late flowering phenotype compared to the wild type.Through further analysis of the expression of rice flowering regulatory genes,it was found that OsMOSl may regulate the flowering time of rice through the OsGI-Hdl-Hd3a flowering pathway.Cold tolerance analysis found that the mutation of OsMOS1 gene increased cold tolerance of rice seedlings.The above studies indicate that the OsMOS1 gene plays an important role in the regulation of rice seeding and flowering development,and it negatively regulates the cold tolerance of rice seedlings.2.In this study.several mutant lines of the OsCHR5 gene were generated by CRISPR/Cas9 editing.Through the genotype analysis of these mutants,it was found that rice plants homozygous with the complete knockout of OsCHR5 gene could not survive.Analysis of the hybridization progeny of an OsCHR5 gene mutant and the wild type showed that the deletion of OsCHR5 causes the death of male gametophyte and significantly reduces the vigor of female gametophyte in rice.Compared with the wild type,the reduction of function OsCHR5 mutant showed a reduced seed setting rate and an early flowering phenotype under long-day growth conditions.The disease resistance test found that compared with the wild type,the reduction of function OsCHR5 mutants had enhanced resistance to rice blight.The above studies indicate that the OsCHR5 gene is not only an essential gene for gametophyte development in rice,but also participates in the regulation of rice flowering and rice resistance to bacterial wilt.