水稻孕穗期耐冷基因CTB4b的克隆与作用机理研究

水稻是重要粮食作物之一，起源于热带和亚热带，因而对低温敏感。水稻在不同生长时期都易遭受低温冷害，尤其是孕穗开花期，低温冷害直接造成水稻产量的不可逆的损失，因此克隆水稻孕穗期耐冷基因具有重要意义。本研究利用孕穗期耐冷的高原粳稻材料昆明小白谷和冷敏感的粳稻材料十和田为亲本，通过多年杂交回交构建定位群体，最终在4号染色体上发现了一个新的控制水稻孕穗期耐冷的基因CTB4b。核苷酸比对分析发现该基因的功能位点可能位于编码区。利用组织及诱导表达分析候选基因的表达特征，同时构建过表达、互补、RNAi载体，通过遗传转化验证基因的功能。通过酶活测定、脂质组分析等一系列生理生化及分子生物学实验分析其孕穗期耐冷作用机理。同时我们利用实验室已有的微核心种质的表型和深度测序的基因型数据明确基因的起源演化规律。该基因的克隆和作用机理研究不但为水稻耐冷理论研究积累经验和数据，而且为水稻耐冷品种选育提供线索。

Rice is one of the most important crops; it originates from tropical and sub-tropical area thus sensitive to low temperature. Rice is suffered from low temperature especially at the booting stage, low temperature leads to irreversible harm in rice yield. Therefore it is important to clone genes controlling cold tolerance at the booting stage and illustrate the molecular mechanism of cold tolerance. In our research, we used a cold tolerant temperate japonica variety from high plateau called “Kunmingxiaobaigu” crossed with a cold sensitive variety “Towada” to generate a series of NILs. After hybrid and self-cross for several years, we finally find a new gene controlled cold tolerance in rice and originate it as CTB4b. Nucleotide alignment demonstrated that functional SNPs may exist in the coding region of CTB4b. Using tissue and cold-induced expression, and constructing over-expression, complementary and RNAi vectors to transform rice materials will confirm the function of the target gene. Some experiments will be conducted by a series of physiological and biochemical techniques such as detection of enzyme activity and lipidomics analysis to analyze the mechanism in cold tolerance. Associated with deep-sequencing data of mini-core collection and phenotype, we will illustrate the rule of origin and evolution of CTB4b. Cloning and illustration of the mechanism of this gene will not only provide experience and data for research on cold tolerance in rice but also have a clue on breeding cold-tolerant rice materials.