小粒野生稻抗白背飞虱新基因的精细定位与育种利用

Whitebacked planthopper (WBPH) is an important pest in rice production, not only harms rice directly, but also intermediates other pathogen or virus during feeding process, and causes serious threat to the safe production of rice in China. Identification of resistance genes and development of WBPH-resistant varieties is an economical and effective way to control this pest. In our preliminary study, a set of chromosome segment introgression lines was constructed by using Oryza minuta, a tetraploid wild rice, highly resistant to WBPH, as donor, and Oryza sativa as receptor. Through insect-feeding screen and field test, two introgression lines with ideal agronomic traits and highly resistance to WBPH were developed, and the genetic characteristics of their new resistance genes had been analyzed. In this project, these 2 materials will be used to construct mapping populations by crossing and back crossing with 9311. Through insect resistance identification and marker-assisted selection, new resistant genes conferring resistance to WBPH from Oryza minuta will be fine-mapped and ready for map-based cloning. At the same time, the new resistant genes will be pyramided to the main hybrid rice parents through marker-assisted selection and hence provide genetic resources and technical support for durable resistant rice breeding.

白背飞虱是水稻生产上的一种重要害虫，不仅直接危害水稻，还在取食过程中传播其他病害和病毒，严重威胁我国水稻的安全生产。发掘和鉴定新的抗虫基因，选育抗虫品种是最经济有效的防治手段。我们在前期研究中已利用高抗白背飞虱的四倍体小粒野生稻（Oryza minuta）为供体，栽培稻为受体，构建了一套染色体片段导入系，从中筛选出了2 份农艺性状优良、高抗白背飞虱的材料，并对它们拥有的新抗性基因进行了遗传分析。本研究就是利用这2 份高抗白背飞虱的材料与9311 杂交和回交构建作图群体，通过抗虫性鉴定和分子标记筛选，对来自于小粒野生稻的抗白背飞虱基因进行鉴定与精细定位，为图位克隆基因做准备；同时开发其便于进行标记辅助育种的分子标记，通过标记辅助选择培育多个当前主栽杂交稻亲本的抗性基因导入系和抗白背飞虱多基因聚合系，为持久抗性水稻新品种培育提供基因来源和技术支持。

白背飞虱是水稻生产上的一种重要害虫，不仅直接危害水稻，还在取食过程中传播其他病害和病毒，严重威胁我国水稻的安全生产。发掘和鉴定新的抗虫基因，选育抗虫品种是最经济有效的防治手段。我们从2份以小粒野生稻（Oryza minuta）为供体，栽培稻为受体，构建的染色体片段导入系中定位了5个抗白背飞虱的QTL；将2个效应值较大的QTL，qWbph4和qWbph6.2，分别定位在水稻第4号染色体 135 Kb的区间和第6号染色体 120 Kb的区间，并开发出6个相应简便分子标记应用于分子标记辅助育种；随后，将抗白背飞虱新基因Wbph9（t）（原名：qWbph6.2）定位在9311基因组参考序列的 60 Kb以内，该区间有7个功能基因，通过表达分析和序列比对，确定其候选基因是Wbph9-5；同时通过标记辅助选择培育了多个当前主栽杂交稻亲本的抗性基因导入系和抗白背飞虱多基因聚合系。本研究的完成，不仅为克隆抗白背飞虱的基因奠定了基础，还为培育持久抗性水稻新品种提供基因来源和技术支持。