抗褐飞虱基因近等基因系的构建以及QBph4的克隆研究

The brown planthopper (Nilaparvata lugens St?l; BPH) has become the most destructive pest in rice-producing areas. Host-plant resistance is the most effective and environment friendly strategy in the management of BPH. However, there is very low BPH resistance genes used in rice improvement and the knowledge about the gene effects, resistance mechanisms and utilization in breeding is still low. In this project, we can use many BPH resistance inrogression lines from diverse wild rice as our research materials, and develop efficient marker-assisted selection (MAS) system for BPH resistance genes. Using MAS based conditional backcross breeding, we can introgress seven major BPH resistance genes into 9311, an elite indica, to develop a serials of 9311 near isogenic lines (NILs) harboring these genes. Furthermore, a new BPH resistance gene QBph4 in the BPH introgression line from oryza officinalis, was identified and fine mapped to a 33Kb region in the short arm of rice chromosome 4. Based on this work, we can further clone QBph4 and analyze the function and resistance mechanism of this gene. The new development of this work will provide more valuable genes for BPH resistance improvement in rice breeding, and a feasible strategy in the management of BPH using host-resistance in rice.

褐飞虱是水稻最重要的害虫，利用水稻抗性基因培育持久高抗褐飞虱品种是目前最为有效、经济和安全的防控褐飞虱策略。目前育种家对褐飞虱抗性资源利用很少，对褐飞虱抗性基因的效应、抗性机制、遗传和育种应用不多。本项目以来源于多种野生稻的优异抗褐飞虱基因的导入系为研究材料，通过构建目前已经定位的水稻主效褐飞虱抗性基因的分子标记辅助选择体系，结合常规回交育种将7个抗褐飞虱基因分别导入到9311中，构建这些基因在9311遗传背景的近等基因系。同时通过图位克隆法克隆本课题发现的1个的褐飞虱抗性基因QBph4，评价其基因效应、解析基因的功能和抗性机制，研究结果为褐飞虱抗性育种提供更多的基因资源，为培育持久稳定的褐飞虱抗性品种培育提供理论依据。

摘要：本项目利用MAS技术把来源于9个供体的13个褐飞虱抗性基因[RH (Bph3 and Bph17), B5 (Bph14 and Bph15), IR54751-1-2-44 (QBph3 and QBph4), IR65482-4-136 (Bph10), IR71033-121 (Bph20 and Bph21), IR65482-7-216 (Bph18), Swarnalata (Bph6), Pokkali (Bph9) and BR96 (Bph24)]，分别导入到93-11中，通过正向选择，反向选择和RICE6K芯片筛选，最终得到了这13个近等基因系Bph14-NIL，QBph3-NIL，QBph4-NIL，Bph17-NIL，Bph15-NIL，Bph20-NIL，Bph24-NIL，Bph6-NIL，Bph3-NIL，Bph9-NIL，Bph10-NIL，Bph18-NIL和Bph21-NIL。我们检测了这些近等基因系的苗期抗性，褐飞虱的蜜露分泌量和致死率，发现这些抗性基因的导入，明显地改良93-11对褐飞虱的抗性，减少了褐飞虱地蜜露分泌量并增加了其致死率。同时，我们还利用AUS69和IR65482-17-511-5-7两个稻飞虱抗性材料分别构建的F2:3群体，定位了3个稻飞虱抗性主效基因，为稻飞虱抗性基因克隆及其分子育种提供了重要基因和资源。