红三叶遗传图谱构建及抗白粉病基因QTL定位

本研究以感(岷山红三叶)、抗(澳大利亚红三叶品种♀Sensation×Renegade♂杂交新品系“甘农PR1”)白粉病红三叶材料为父母本杂交并种植成苗经人工接菌后筛选出抗、感白粉病的F₁群体为作图群体,利用AFLP标记构建红三叶高密度遗传图谱,并利用区间作图法对抗白粉病QTL进行了定位分析,可以为红三叶抗白粉病基因克隆和转基因等分子辅助育种奠定基础。结果表明,149个AFLP标记构建得到的遗传图谱包含7个连锁群(LG1,LG2,LG3,LG4,LG5,LG6和LG7),遗传图谱的总距离为640.5 cM。其中,LG1连锁群的遗传距离(140.6 cM)和标记间平均距离(9.4 cM)均最大;LG4连锁群的遗传距离(55.2 cM)和标记间平均距离(1.8 cM)最小。应用区间作图法对红三叶抗白粉病基因进行QTL分析定位,共检测到5个抗白粉病相关QTL位点(qrp-1,qrp-2,qrp-3,qrp-4和qrp-5),其中qrp-1、qrp-2、qrp-3和qrp-4位于LG4连锁群上,qrp-5位于LG5连锁群上。5个QTL位点对抗白粉病的贡献率为29%~90%,qrp-1对红三叶白粉病抗性的贡献率最大(90%),为主效QTL。

Construction of the AFLP linkage map and QTL analysis of powdery mildew resistance in red clover

In this study,F1 generation red clover plants,obtained from crossing red clover varieties resistant (Gannong PR1,and Sensation and Renegade from Australia) or sensitive (Minshan) to powdery mildew,were artificially inoculated with powdery mildew and used as a quantitative trait locus (QTL) mapping population.AFLP markers were used to construct the genetic linkage map and the interval mapping method was used to locate the QTL for resistance to powdery mildew.This study will establish foundation to gene location and transgenosis of red clover.It was found that the linkage map based on 149 AFLP markers included 7 linkage groups (LG1,LG2,LG3,LG4,LG5,LG6 and LG7).The map covers a total distance of 640.5 cM.LG1 was found to be the largest (140.6 cM with the average distance between two markers being 9.4 cM),while LG4 was found to be the smallest yet with the highest marker density of any LG (55.2 cM in length with 1.8 cM on average between markers.Five QTLs (qrp-1,qrp-2,qrp-3,qrp-4 and qrp-5) related to powdery mildew resistance,and located on LG4 and LGS,were detected.The phenotypic variance explained by the 5 QTLs for powdery mildew resistance ranged from 29％ to 90％,with the largest contribution being from qrp-1.Therefore,qrp-1 was identified as the main gene controlling powdery mildew resistance in red clover.