水稻细菌性条斑病抗性新基因的分子标记精细定位与育种利用研究

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 15% to 20%, but can reach 40% to 60% in severe cases. 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 fine-mapped, which limits the application of the BLS- resistance resources in rice breeding. In our previous studies, 2 rice accessions, which were derived from Guangxi common wild rice (O. rufipogon Griff.), were screened and identified to be highly resistant to BLS. It was shown preliminarily that the BLS resistance in these two accessions might be controlled by a novel gene respectively. In this study, the novel resistance genes will be further verified and fine mapped. The effective markers will be developed to help incorporate these resistance genes into the main rice cultivars. The expected results will facilitate the positional cloning of new resistance genes and provide the ideal materials for the cultivation of BLS- resistance varieties

水稻细菌性条斑病（简称水稻细条病）是水稻的重要病害，已经严重威胁着亚洲热带和亚热带地区水稻生产。由细条病导致的减产一般在15%-20%，严重时达40%-60%。选育抗病品种是防治该病最为经济、有效和环保的途径。水稻细条病抗性被认为是数量性状，主要受多基因控制，因此其基因的定位和克隆较为困难，迄今只有极少的细条病抗性数量性状位点被精细定位，这限制了水稻抗细条病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2份对水稻细条病具有高抗性的材料，研究表明它们可能携带抗细条病的新的主基因。本项目拟进一步鉴定和精细定位这2份材料所携带的抗性基因，开发实用分子标记，采用常规育种与分子标记辅助选择相结合的方法，把鉴定的抗性基因转育到当前主栽的栽培稻品种中，并且获得一批抗细条病基因导入系、聚合系。研究结果将有助于水稻抗细条病基因的分子标记辅助选择和图位克隆，为培育水稻抗细条病新品种提供理想材料。

水稻细菌性条斑病（bacterial leaf streak，BLS），简称为细条病，是由黄单胞菌的水稻变种Xanthomonas oryzae pv.oryzicola，简称为Xooc引起的严重水稻病害，是我国重要的检疫性水稻病害。控制该病害最经济有效的方式是抗性品种的培育及推广。普通野生稻经过长期的自然选择，具有多种优异的抗性。为此，本课题对广西普通野生稻中的抗细条病新基因进行鉴定、精细定位和育种利用研究。分别以2份具有高抗性，且抗性稳定的普通野生稻材料为抗病亲本，以测序品种9311为感病亲本，通过杂交、回交和自交，构建作图群体。结果从这2份材料中各鉴定出1个抗细条病新基因。将抗源DP15的抗性基因定位于第1号染色体1.1M范围内，将抗源DP9的抗性基因精细定位于第2号染色体170Kb区域内。根据水稻基因注释网对定位区段内候选基因进行分析，表明该区段有21个候选基因，经过HRM（高精度熔解曲线）检测，发现基因LOC_Os02g39960与水稻抗细条病表型完全连锁，是最可能的后选基因。为抗性基因的图位克隆奠定了很好的基础。本研究还开发了4个简便分子标记，可以提高抗性基因的选择效率。获得了改良的抗性品系3个，为水稻抗细条病品种的培育提供了重要的育种材料。