普通小麦品种“兰引1号”持久抗条锈性基因解析

Understanding the molecular basis of durable resistance to stripe rust in wheat cultivar, and identifying novel resistance genes to improve cultivar and deployment of them in wheat production, is an important strategy for solving the easily susceptible to the rust pathogen in wheat in South of Gansu, a hotspot for stripe rust in China. Wheat cultivar Lanyin 1 conferred durable resistance to stripe rust in both seedling and adult-plant stage during 22 years in wheat-growing region of Southern Gansu. Recently, using genome-wide association analysis (GWAS), we found multiple adult-plant resistance (APR) QTLs to stripe rust in cultivar Lanyin 1. Based on these results, this project is designed to understand the molecular mechanism of the resistance to stripe rust in cultivar Lanyin 1 by fine mapping the resistance genes and QTLs, and identifying the causative mutations in candidate resistance genes in confidence interval of QTL and finally find markers closely linked to these resistant genes for molecular breeding via SNP chip and Bulk Segregant RNA-Seq (BSR-Seq). This study is expected to deepen our understanding on molecular basis of durable resistance to stripe rust in wheat and provide important genes on improvement resistance of cultivars through molecular breeding.

解析持久抗条锈小麦品种的抗病性机理、发掘新的抗病基因，提高品种抗病持久性，是解决我国条锈病源头区域甘肃陇南小麦品种抗性易“丧失”的重要途径。陇南小麦品种兰引1号兼具苗期和成株期抗病性，抗病性保持约22年未变。申请人所在课题组前期进行品种成株抗条锈性全基因组关联分析发现兰引1号含有多个抗性QTL。本项目拟在此基础上，利用高通量SNP芯片和混池转录组测序（BSR-Seq)技术，进一步对兰引1号苗期和成株期抗条锈性基因解析：精细定位抗病基因和抗性QTL，发掘育种实用性分子标记，在抗病基因/QTL置信区间发掘候选抗病基因序列，鉴别引起抗病基因的因果突变位点。预期结果将加深人们对小麦持久抗病性分子机理的理解，并为持久抗病性小麦分子育种提供重要基因和标记。

甘肃陇南是我国小麦条锈病重要的西北越夏菌源区。发掘和利用抗病基因是该区域小麦育种的首要任务。法国小麦品种兰引1号（Pascal）苗期感病，但长期在陇南生产中表现优异的成株抗病性。本研究对“辉县红×Pascal”的220个F5重组自交系进行多个环境下的抗病性鉴定，利用55K SNP芯片进行基因型分析和复合区间作图法，发现Pascal含有3个新的条锈病成株抗性QTL QYr.gaas-1AL、QYr-gaas-3DL和QYr.gaas-5AS，解释11.0%至23.1%的表型变异。开发了与QTL位点紧密连锁的SNP标记AX-111218361-AX-110577861、AX-111460455-AX-10798599和AX-111523523-AX-110028503。将与抗病性效应较大的QYr.gaas-3DL紧密连锁的SNP标记AX-109580758转换为KASP标记HXPA-3D，并检测了220个RIL家系，将QYr.gaas-3DL定位在距离标记HXPA-3D 1.5-3.5 cM的位置。利用QYr.gaas-1AL和QYr.gaas-3DL位点的KASP标记BSE-1A-12和HXPA-3D检测153份中国和全球核心种质资源，发现两个位点均在国外种质资源中出现频率高，在中国小麦品种和育种系中较低。QYr.gaas-1AL和QYr-gaas-3DL的KASP标记BSE1A-12和HXPA-3D可用于培育抗条锈病小麦品种。结合BSE-Seq，发现QTL QYr.gaas-1AL区间内共有18个高置信基因，其中基因TraesCS1A02G313700、TraesCS1A02G313800和TraesCS1A02G314900被初步确定为抗病候选基因。研究结果明确了菌源区小麦兰引1号（Pascal）持久抗条锈病性的分子机理，并为持久抗病性小麦分子育种提供重要基因和标记，也为下一步开展抗病新基因精细定位和克隆分析奠定了基础。