中国小麦地方品种抗白粉病基因Pm24克隆

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is an important foliar disease of wheat worldwide. Chinese wheat landrace are very important resources for powdery mildew resistance genes with durable and borad spectrum resistance after thousands years natural and artificial selections. Cloning and utilization powdery mildew resistance genes from wheat landrace have significant impacts on modern wheat improvement. In our previous researches, we have performed genetic analyses, fine genetic linkage maps of powdery mildew resistance genes derived from wheat cultivar (lines) Hulutou (MlHLT/Pm24). In this proposal, we are planning to conduct map-based cloning and haplotype analysis of the Pm24 loci. The most recently released Chinese Spring reference genome sequences Ver 1.0 (International Wheat Genome Sequencing Consortium, IWGSC), Aegilops tauschii reference genome sequences BSR-Seq and comparative genomics analysis are used to develop fine genetic linkage maps and construct BAC physical maps of the Pm24 genomic regions towarding map-based cloning of the loci. Use PCR amplification, haplotype variations of the Pm24 genomic regions in Chinese mini-core collections, landraces and Aegilops tauschii will be analysised to identify key nucleotide variations associated with powdery mildew resistance or susceptility. Powdery mildew susceptible EMS mutants will be developed also to validate the function of candidate resistance genes. The powdery mildew resistance function of the cloned Pm24 candidate genes will be finally confirmed by transgenic complementary experiments. Based on the above results, developed the Pm24 functional marker for molecular marker assisted breeding.

白粉病是严重影响小麦产量的重要病害。中国小麦地方品种蕴含丰富的抗白粉病基因，历经几千年自然和人工选择依然保持广谱和持久抗性。克隆和利用地方品种中的抗白粉病基因，对小麦遗传改良具有重要意义。在前期进行精细定位的基础上，本研究对来源于我国小麦地方品种的抗白粉病基因Pm24（葫芦头）进行图位克隆、单倍型变异分析和抗病机理研究。综合利用小麦参考基因组序列、BSR-Seq、比较基因组学分析和物理图谱构建图位克隆Pm24候选基因；采用PCR扩增的方法，分析Pm24候选基因所在基因组区段在小麦核心种质、地方品种和粗山羊草中的单倍型变异，并与抗病性进行关联分析。通过感白粉病EMS突变体和转基因遗传互补验证Pm24基因功能。开发Pm24的功能标记，应用于抗白粉病分子标记辅助育种。

小麦是我国重要粮食作物之一，其生产与保障国家口粮绝对安全直接相关。小麦白粉病是由高度专化性寄生菌布氏禾白粉菌（Blumeria graminis f.sp. tritici）引起的真菌性病害，是危害小麦生产的重要病害之一。发掘和利用多样化抗白粉病基因培育抗病新品种是防治白粉病最经济、安全、有效的途径。通过图位克隆的方法从中国地方品种葫芦头中克隆了Pm24基因。Pm24基因编码一个串联激酶，将其命名为WTK3 (WHEAT TANDEM KINASE 3)，通过遗传转化和EMS突变体分析证明了Pm24的功能。单倍型分析和转基因结果表明第一个激酶结构域上的仅有6 bp缺失才能使得WTK3获得白粉病抗性。