纹枯病是水稻最重要的病害之一，水稻对该病的抗性受多基因控制，抗病育种中只能应用数量抗病基因。研究表明中抗品种特青（TQ）第9染色体上存在一个主效抗纹枯病数量基因qSB-9TQ，具有较高育种应用价值。通过构建高精度染色体单片段重叠代换系，我们将该基因精细定位在21kb区间内，包含3个表达的基因。. 在此基础上，本项目将通过测序、转基因功能验证，克隆qSB-9TQ；通过组织病理学、代谢物分析、表达模式、亚细胞定位、RNA-seq和激素处理等方法，明确其抗病机制和信号调控途径；筛选其互作蛋白，明确互作蛋白的生物学功能及与qSB-9TQ间的相互调控关系；分析其在水稻自然品种中的优异复等位变异及分布特征，开发功能标记服务于抗病育种。结果将加速qSB-9TQ的育种应用，丰富水稻抗纹枯病分子机理的理论知识。

Sheath blight (SB) one of the most serious diseases in rice worldwide, causing significant grain losses annually. Rice resistance to SB is controlled by polygenes, namely quantitative trait locus (QTL). Utilization of SB resistance QTLs is the most important approach to develop SB resistance variety. Previous studies have showed that qSB-9TQ, a major quantitative resistance gene from Teqing (TQ) with moderate resistance, is of great breeding potential in rice breeding against SB disease. For finemapping qSB-9TQ, we developed a set of chromosome single segment substitution lines (CSSLs), in which the substituted TQ segments are contiguous overlapping the preliminary mapping interval of qSB-9TQ with high resolution. After phenotyping, we finally narrowed the gene down to a 21kb region including 3 expressed genes. . To further investigate the resistant mechanism of qSB-9TQ, in this project we will 1) to clone qSB-9TQ by sequencing and transgene verification experiments; and 2) to analyze its resistant mechanism and signaling pathway associated with SB resistance by the methods like histopathology, metabonomics, qRT-PCR, subcellular localization, RNA-seq and phytohormone treatments; and 3) to identifiy its interaction proteins and determine the roles of interaction proteins in qSB-9TQ medidated SB resistance; and 4) to mine its elite allelic variants in rice natural germplasms as well as developing functional molecular markers for breeding. Results in this study will accelerate the ultization of qSB-9TQ in developing SB resistance variety, and provide new knowledge for understanding the mechanism of rice resistance to SB disease.