东乡野生稻耐冷候选基因的功能验证及分子机理研究

Cultivated rice(Oryza sativa L.) is one of the most important crops in China. Low temperature has a direct impact on rice yield. The rice production in Jiangxi province is always affected by low temperature. In recent years, cold damage happens frequently due to the abnormal climate over the world. It seriously restricts the rice production, and affects the stable food production in our country. Therefore,campaigning tolerance reseach,understanding the cold tolerance mechanism and cultivating new cold tolerance varieties are important.Dongxiang wild rice is the world's most north wild rice that has strong cold tolerance.Expression profiles of Ganxiang B and Ganxiang B/Dongxiang wild rice segment substitution Line with strong cold tolerance in low and normal temperature are sequenced in this study, and several cold stress induced genes are found.The new cold tolerance genes can be obtained by identifying the phenotype of transgenic plants with gene konckout and over expression.The molecular mechanism research of cold tolerance genes in this study can provide a solid foundation for the cold tolerance breeding of rice.

水稻是我国主要粮食作物之一。低温会对水稻的产量产生直接影响。江西省的水稻生产也常受到低温的影响。近年来世界气候变化异常，冷害频发，严重制约着水稻的种植生产，危及我国的粮食安全生产。因此，开展水稻耐冷研究，了解其耐冷机制并培育耐冷新品种显得尤为重要。东乡野生稻是世界最北的野生稻，拥有极强的耐冷性。本研究通过对赣香B与东乡野生稻的强耐冷片段代换系及赣香B在低温及常温条件下的表达谱进行测序，筛选到了多个受冷胁迫诱导表达的基因。通过敲除和过表达转基因实验及后代转基因植株的表型鉴定，可以从中发现新的耐冷基因。通过研究耐冷基因的分子作用机制，可以为水稻的耐冷育种提供坚实的基础。

随着农业生产条件的改变，长江中下游地区双季早稻直播省工增效，受到种植户的欢迎，近年来面积迅速上升。但双季早稻直播容易遭受低温胁迫，严重制约着水稻的种植生产，危及我国的粮食安全生产。因此，发掘的耐冷种质资源和培育耐冷水稻品种是解决这一问题的有效途径之一。前期研究中通过对赣香B与东乡野生稻的强耐冷片段代换系及赣香B在低温及常温条件下的表达谱进行测序比较，筛选到了多个受冷胁迫诱导表达的基因。本研究在此基础上，通过遗传转化验证筛选出来的多个候选基因，鉴定了2个新的耐冷基因，OsOMTL1和OsHI-XIP。两个基因存在显著的籼粳分化，均受到冷胁迫的诱导表达，在赣香B背景下超表达增强了耐冷性。同时以东乡野生稻渗入赣香B耐冷株系为亲本，选育具有耐冷性的水稻三系不育系赣野A（赣审稻20190066）。该项研究不仅丰富了水稻的耐冷分子机制，也为今后培育耐冷直播水稻提供了新的分子和材料基础。