与小麦赤霉病抗性紧密连锁的基于AFLP片段的STS标记开发

摘要

DNA序列标签位点(STS)是一个操作简便和花费低的分子标记体系,将与某一性状密切连锁的AFLP(扩增片段长度多态性)片段转换成STS标记可直接用于分子育种工作中.本研究利用Ning 7840和Clark的重组自交系及AFLP技术,探测到一个与小麦赤霉病抗性紧密连锁的坐落在染色体3BS的主效数量特性位点(QTL),发现5个Pstl-AFLP片段与该QTL显著关联;其中2个片段与赤霉病抗性达到50%左右的表型变异解析度,一个为35个碱基的相引相片段,另一个为222个碱基的相斥相片段.222个碱基的DNA片段被克隆和测序,发现11个克隆中含有5种不同的DNA序列,其中一种序列在5个克隆中完全一致,该序列被用来作为设计STS标记的DNA模板.经多次实验,开发出了一个共显性STS标记.该STS标记与原222个碱基的AFLP片段谱带(banding pattern)完全一致,具有鉴别小麦育种材料赤霉病抗病强弱和加速抗病育种进程的潜力.%Conversion of AFLP (Amplified fragment length Polymorphism) markers into sequence-tagged site (STS) markers may generate breeder-friendly markers for marker-assisted selection (MAS). One major QTL on chromosome 3BS was mapped by using AFLPs and the recombinant in-bred population from the cross of Ning 7840/Clark. Fine mapping of the QTL region identified five PstI-AFLP markers significantly associated with the major QTL. Two of them individually explained up to 50% of phenotypic variation for scab resistance. One 35 bp DNA fragment linked to the QTL in coupling phase and another 222 bp fragment linked to the QTL in repulsing phase. The larger DNA fragment was cloned and sequenced. Five different DNA fragments were recovered from the cloned fragment, and one with five identical copies was selected to design STS primers. A co-dominant STS marker was amplified and showed the same segregation pattern as the original AFLP. Application of this marker in breeding programs may speed up breeding process to enhance scab resistance in wheat.