扬麦158抗赤霉病基因的精细定位及效应评价

Fusarium head blight (FHB) is a serious threat to food security, and it is important for development of resistant varieties to explore resistant genes. Yangmai 158 with moderate FHB resistance dominated the fifth variety rotation in the middle and lower reaches of the Yangtze River, but there is no Fhb1. In our previous study, we identified a stable QTL of QFhb-5A from Yangmai 158 on the long arm of 5A, which was different from the loci reported previously by comparative genomics. Then phenotyping and genotyping on one hundred wheat varieties were conducted to prove that QFhb-5A had significant effect on FHB resistance. In future study, we would expand segregating population (≈5000) and develop new molecular markers in the interval by whole genome resequencing and comparative genomics, and with which QFhb-5A would be narrowed to an interval of about 100 kb. In addition, we would transformed QFhb-5A into susceptible varieties of Jimai 22 and Zhoumai16 to evaluate its effect, and some valuable intermediate lines would be obtained.

小麦赤霉病严重威胁粮食安全，发掘小麦赤霉病抗性基因对培育抗病品种具有重要意义。扬麦158是长江中下游麦区第五次品种更换的主体品种，其赤霉病抗性达到中抗水平。分子标记检测显示扬麦158不携带Fhb1位点，其抗性可能来源于其他抗源。在前期研究中，我们通过连锁分析鉴定到一个来源于扬麦158的稳定抗性位点QFhb-5A，通过比较基因组学分析发现其不同于之前报道的抗病位点。进一步对100份小麦品种进行标记及表型鉴定，证实QFhb-5A对赤霉病抗性有显著影响。在此基础上，本研究拟继续扩大剩余变异群体(约5000株)，通过基因组重测序等手段加密分子标记，实现QFhb-5A的精细定位。同时，构建感病品种济麦22、周麦16的近等基因系，开展效应评价，并获得一批具有应用价值的中间材料。

小麦赤霉病严重威胁粮食安全，培育抗病品种是减轻赤霉病危害的主要途径。除抗赤霉病基因Fhb1与Fhb7外，其他抗病基因的应用报道仍然较少，发掘小麦赤霉病抗性基因对培育抗病品种具有重要意义。扬麦158是长江中下游麦区第五次品种更换的主体品种，其赤霉病抗性达到中抗水平。分子标记检测显示扬麦158不携带Fhb1、Fhb2、Fhb4及Fhb5等已知抗病位点，本项目研究的QFhb-5A可能是其抗性的重要来源。在本项目的支持下，我们通过精细定位将QFhb-5A的候选区间缩小至1.1 M，为进一步克隆该基因奠定了良好的基础，并在导入系材料、高世代育种材料、国家及省区域试验材料中对QFhb-5A开展了系统的效应评价工作，证实Qfhb-5A可以显著提高赤霉病抗性，并可与Fhb1协同提升赤霉病抗性。此外，应用Qfhb-5A的连锁标记开展抗赤霉病分子标记辅助选择，成功筛选获得一批抗性突出的材料，一方面参加国家或省区域试验，一方面作为抗性亲本应用抗赤霉病育种。