水稻"东野型"细胞质雄性不育基因的克隆及恢复基因定位

The wild abortive (WA) male sterile cytoplasm has been successful utilized and has played an important role in rice production. Nevertheless, there is a potential risk of the genetic uniformity of WA cytoplasm. So it is necessary to explore new male-sterile cytoplasm sources. During the research on the utilization of Dongxiang wild rice, a novel cytoplasmic male sterile source, designated DongYe-type, was identified from Dongxiang wild rice by crossing Dongxiang wild rice as female with Zhongzao 35, an early indica variety, as male and successive backcrossing with Zhongzao 35. Testcross experiments showed the relationship of restoring and maintaining of DongYe CMS was entirely different from all known CMS types. Afterwards, DR249, a strong restorer for DongYe CMS was obtained. Inheritance analysis showed that the fertility restoration of this CMS was governed by three pairs of independent dominant genes. In this study, to clarify the molecular mechanisms of DongYe type CMS, firstly, the full mitochondrial genome of DongYe CMS line and its maintainer line will be sequenced. Subsequently, analysises on the mitochondrial genome sequences will be conducted to search the candidate gene associated with DongYe CMS by the method of bioinformatics and comparative genomics. The CMS gene function will be verified by transformation experiments. Meanwhile, high backcross generations and near isogenic lines (NILs) derived from a cross between DongYe 1A and DR249 will be constructed to fine mapping the three restorer genes by map-based cloning. These analyses will help us enhance the understanding of the mechanisms of rice CMS and provide the molecular markers for marker-assisted selection in DongYe-type restoring line breeding.

水稻野败型不育细胞质的成功利用在水稻生产上发挥了巨大作用，但也存在遗传单一性带来的潜在风险。为发掘新的细胞质源，我们在对东乡野生稻的利用研究中，以早籼中早35为轮回亲本育成东野胞质雄性不育系东野1A，并发现东野CMS与已有CMS类型的恢保关系完全不同，我们将这种新质源定名为"东野型"，随后筛选到强恢复源DR249，并探明东野CMS的恢复受三对独立的显性基因控制。本项目拟对"东野型"CMS及其保持系的线粒体基因组进行完整测序，利用生物信息学和比较基因组学筛选东野CMS的候选基因，并通过转基因途径确定不育基因，阐明东野型CMS不育的分子机制。同时，利用东野1A和DR249杂交构建高世代回交分离群体和近等基因系，结合图位克隆策略，对三对育性恢复基因分别进行精细定位。通过本项目的实施，将进一步丰富水稻细胞质雄性不育的分子机制，同时也为"东野型"恢复系的培育提供可用于辅助选择的分子标记。

水稻野败型不育细胞质的成功利用在水稻生产上发挥了巨大作用，但也存在遗传单一性带来的潜在风险。为发掘新的细胞质源，我们在对东乡野生稻的利用研究中，以早籼中早35 为轮回亲本育成东野型胞质雄性不育系东野1A，并发现东野型不育与已有胞质不育类型的恢保关系完全不同。本项目对东野1A的线粒体基因组进行了测序和组装，大小约499kb。利用生物信息学和比较基因组学分析筛选东野1A的不育候选基因，并通过转基因验证了不育基因。根据东野1A的线粒体序列变异，设计了能够特异鉴定东野型细胞质雄性不育源的分子标记DW-M1。利用东野1A 和东乡野生稻株系DR249杂交构建近等基因系，利用90K SNP芯片扫描，将三对育性恢复基因分别定位在8、10和11染色体上，为进一步精细定位和克隆基因奠定了基础。通过分离群体将Rf11定位在300kb的范围内。利用近等基因系明确了三对恢复基因的效应大小：Rf11>Rf10>Rf8。本项目的实施丰富了东野型新三系杂交水稻体系的理论基础。