冷胁迫是制约水稻生产的主要非生物胁迫之一。我国栽培的水稻常遭遇“倒春寒”或“寒露风”等异常气候因素而造成冷害，严重影响水稻的产量与品质。在前期工作中，我们利用基于籼稻Nona Bokra为供体构建的染色体单片段替换系发现一个苗期冷敏感主效QTL qCSS12，并将其精细定位在68kb的范围内。本项目拟通过测序分析或筛选基因组文库分离该位点上的冷敏感基因；通过互补表达、过量表达、RNAi、以及CRISPR/Cas9基因编辑等方法验证基因的低温表型效应；通过qPCR等方法分析基因的表达模式；通过生物信息学和生化实验方法分析基因的功能及其所介导的生化代谢途径；通过分子进化研究方法揭示该基因与籼粳稻耐冷进化分歧的关系及其在该进化事件中的地位。通过本项目研究，可从水稻中克隆一个低温胁迫相关调控基因，揭示耐冷调控分子机制，为耐冷水稻品种的培育提供有利基因资源；同时初步揭示籼粳稻耐冷性进化分歧可能过程。

Low temperature occurred in late spring or in autumn is of great threat to the rice production in China, resulting in heavy yield loss and lowered rice quality. Therefore, cold damage is one of the most important limiting abiotic stresses in rice production. In our previous studies, we fine mapped a major QTL, qCSS12, which confers the cold-sensitive at seedling stage, to about 68-kb region flanked by molecular markers M14 and M15 on short arm of chromosome 12 by using a chromosome segment substitution line (CSSL). The CSSL derived from introgressed a cold sensitive indica rice, Nona Bokra, into cold tolerant japonica rice, Koshihikari by backcrossing. This proposal aims at cloning and functional dissection of the cold sensitive gene on the qCSS12 locus. Here, qCSS12 will be isolated by means of candidate genes' sequencing analysis or genomic DNA library screening, and then the target gene of qCSS12 will be determined by genetic complementation test. Furthermore, the cold sensitive phenotype mediated by qCSS12, will be demonstrated by overexpression, RNAi, and/or CRISPR/Cas9 gene editing of qCSS12. qPCR, Northern Blotting, or in situ hybridization technologies will be employed to analyze the expression pattern of target gene. At last, unraveling the molecular mechanisms of qCSS12 underlying rice cold response phenotype by means of bioinformatics, physiological, and biochemical technologies. Meanwhile, the relationship and roles of qCSS12 in the cold-resistance divergence between indica and japonica rice in the histories of rice domestication will be revealled by phylogenetic analysis of qCSS12. Knowledge and novel gene gained from this study will facilitate the breeding of novel rice cultivars with improved cold tolerance.