Cloning And Functional Research Of A Cold Resistant Gene COR1 In Rice(Oryza Sativa L.)

Temperature is a significant factor that impacts the vegetation distribution on earth. The earthtemperature varies by latitude, leading to plant resources of low latitude, which may can not adapt to thelow temperature, confined to low latitude, and plant resources of high latitude, which may can not fit theenvironmental stress of low latitude, limited to high latitude. Even as one of the most important cerealcrops, rice is not immune. As a common cereal crops, rice nurtures nearly half of the world’s population.However, it is sensitive to the temperature changes during its growth and development. So its producingregion is limited. And even in its suitable farming area, sudden changes in temperature can causereduced rice yield.This study focuses on the cold tolerance of rice during seedling stage. By analyzing the cold-sensitivephenotype of the F2 population derived from a cross between a cold-tolerant japonica varietyNipponbare and a cold-sensitive indica variety V216 during low temperature treatment, we come to theconclusion that the phenotype is controlled by a single recessive gene. The gene was finally isolated bymap-based cloning. Near isogenic lines were also constructed for farther study. The main results were asfollows:1. Significant difference of chlorophyll content between Nipponbare and V216 was detected during19℃ temperature treatment. The gene was finally isolated by map-based cloning and named COR1.Near isogenic lines with NPB and V216 genetic background were constructed separately for fartherstudy. COR1V216 showed frameshift ORF.2. COR1 affects chlorophyll content of rice leaf, as well as the development of chloroplast. V216 andNear isogenic lines with frameshift ORF, showed sharply declined chlorophyll content and retardeddeveloped chloroplast under 19℃ temperature treatment.3. The result of subcellular location analysis proved the prediction that COR1 was is targeted to thechloroplast. And the RNA editing degree analysis indicated that COR1 was involved in the editing ofrps8-182 in chloroplast. Loss function of COR1 leaded to unedited state of rps8 RNA in ricechloroplast.4. The result of conservation analysis implied that there was an association between COR1 homologousgenes and rps8 during evolution. The editing site of rps8-182 might be acquired during the evolution ofangiosperms. The conservation of COR1 homologous genes in monocotyledons may be an adaption tothe need of rps8 RNA editing.5. The analysis of COR1 differentiation between japonica and indica indicated that there weredifferences between japonica and indica varieties in COR1 gene. The related conservative sequence injaponica varieties has a great potential for improving cold tolerance in rice.