抗水稻细菌性条斑病新基因的克隆和抗性机理研究

水稻细菌性条斑病（简称细条病）是水稻的重要病害，已严重威胁亚洲热带和亚热带地区水稻生产。水稻细条病抗性被认为是数量性状，主要受多基因控制，因此其抗性基因的定位和克隆较为困难，迄今只有极少的抗性数量性状位点（QTL）被克隆。对水稻细条病抗性基因及其调控机理认识的缺乏，限制了抗性资源在育种中的应用。我们前期从广西普通野生稻中鉴定了1份高抗细条病的材料，其抗性由一新的主效基因bls2控制，定位在第2染色体170kb范围内，该区段有21个候选基因，发现LOC_Os02g39960与水稻抗细条病表型完全连锁，是最可能的候选基因。本研究拟采用图位克隆的方法克隆该基因，通过过量表达和CRISPR/Cas9技术研究其功能，qRT-PCR分析其表达模式，转录组学、蛋白组学和生物信息学来揭示其上下游基因和基因互作网络。从而阐明bls2的生物学功能和抗性分子机理，为培育水稻抗细条病新品种提供基因资源和理论依据。

Rice bacterial leaf streak (BLS), an important disease in rice, has become a serious threat to rice production in tropical and subtropical regions of Asia. Yield losses from BLS are normally 8% to 32%. Breeding resistant varieties is one of the most economic, effective and environmentally safe ways to control the disease. The BLS resistance in rice has proved to be mainly controlled by quantitative trait loci (QTLs). To date, only a few QTLs for BLS resistance have been cloned, which limits the application of the BLS- resistance resources in rice breeding. In our previous studies, 1 rice accession, which were derived from Guangxi common wild rice (O. rufipogon Griff.), was screened and identified to be highly resistant to BLS. It was shown that the BLS resistance in this material was controlled by a new gene bls2. It was already mapped in a region of 170kb on chromosome 2. Twenty-one candidate genes in the location region were predicted in accordance to the rice gene annotation network. After HRM(high-resolution melt)detection, LOC_Os02g39960 was found completely linked to BLS resistance phenotype, it was the most reasonable candidate gene. In this study, this novel resistance gene will be cloned by positional cloning method. The over-expression and CRISPR/Cas9 gene editing of bls2 in transgenic rice lines will be constructed to verify its function. qRT- PCR will be used to study its expression pattern. Transcriptomics, proteomics and bioinformatics will be applied to reveal its upstream and downstream genes and gene-interaction network. Our results will uncover the bls2-mediated biological function and resistance mechanism, providing the gene resource and theoretical reference for BLS- resistance breeding.