水稻耐冷QTL的克隆与育种价值评价

Cold stress causes various injuries to rice seedlings and is an important factor affecting rice production in low-temperature and high-altitude areas. In our study, a major cold-tolerant quantitative trait loci (QTL) was detected on chromosome 10 of Dongxiang wild rice (Oryza rufipogon Griff.) at the two-leaf stage, which account for 23.2% of phenotypic variance. By fine-map the major locus qRC10-2, qRC10-2 was delimited to a 22.5-kb region between markers qc47 and qc48. In this candidate region, only one gene(Os10g0490100) exhibited up-regulate expression under cold stress. In this result, we are aim to acquire high precision physical map of the qRC10-2 interval by the screen Dongxiang BAC library. After isolating and cloning of candidate genes for the qRC10-2, their physiological function will be certificated by the way of over expression and RNAi silencing. In additional, we aim to breed 93-11, Yuefeng, Y58S near isogenic line with qRC10-2 interval from Dongxiang and evaluate comprehensive cold-tolerant performance at seedling and mature stage. Therefore, it is theoretical and practical significance for underlying molecular mechanism of cold tolerance and realizing of molecular design breeding for cold tolerance in rice.

水稻苗期冷害是影响低温以及高海拔地区水稻稳产的重要因素。东乡野生稻（Oryza rufipogon Griff.）具有极强的苗期耐冷性，本研究组以东乡野生稻作为供体亲本，南京11为轮回亲本，在东乡野生稻第10 染色体上定位到1个主效QTL（qRC10-2），表型贡献率为23.2%。在此基础上，通过精细定位将qRC10-2缩小到22.5Kb范围内，位于标记qc47和qc48之间，区间内含有1个候选基因(Os10g0490100 )，并且受冷胁迫应答上调。本项目拟通过筛选东乡BAC文库获得qRC10-2区间高精度物理图谱，分离、克隆候选基因后通过过表达和RNAi沉默的方法验证其生理功能。同时，通过分子标记辅助选择的方法培育携带东乡qRC10-2区间的93-11、粤丰、Y58S近等基因系，评价其在苗期和成熟期的综合表现。本研究对揭示水稻耐冷的子机理以及实现耐冷分子设计育种具有理论和实践意义。

水稻苗期冷害是影响水稻稳产的重要因素之一。东乡野生稻(Oryza rufi pogon Griff.)具有极强的苗期耐冷性，本研究对来自东乡野生稻第10号染色体耐冷QTL'qRC10-2'精细定位至22.5Kb范围内，位于分子标记qc47和qc48间。通过测序覆盖qRC10-2区间BAC克隆，区间内仅有1个候选基因(Os10g0490100)，并且受冷胁迫应答上调。通过转基因功能验证表明，Os10g0490100编码框的第343碱基变异对水稻苗期耐冷的变化起到关键作用，在耐冷的东乡野生稻中该碱基为‘G’，在冷敏感品种中为‘A’，耐冷基因型主要分布在粳稻以及高海拔的耐冷品种中。此外，通过分子标记辅助选择耐冷基因型qRC10-2(+)在导入到冷敏感品种南京11后能显著其近等基因系苗期、成熟期的耐冷性。qRC10-2功能基因的克隆对揭示水稻耐冷的子机理以及实现耐冷分子设计育种具有理论和实践意义。