小麦-簇毛麦易位染色体库构建及重要农艺基因发掘

Haynaldia villosa has been identified as an important gene resource for wheat genetic improvement. So far, genetic studies involving H. villosa mainly focused on disease resistance genes. Exploration of agronomic genes of H. villosa was rarely reported. In this research, based on a set of wheat-H. villosa substitution lines involving individual chromosomes of 1V-7V, we have developed wheat-H. villosa single chromosomal substitutions of 1V-7V with the same genetic background donored by Yangmai 23, an elite varity, through backcrossing. Agronomic effects of individual H. villosa chromosomes will be revealed at the single-chromosomal level. The ph1b mutant in the Yangmai 23 background has been also created and will be used to induce homoeologous recombinations between H. villosa 1V-7V and wheat chromosomes, respectively. The application of a H. villosa genome-wise specific marker combining with the double distal markers of 1V-7V individual chromosomes will lead to highly efficient detection of wheat-H. villosa translocations in large populations. Thereafter, a wheat-H. villosa compensating translocation bank, spanning the total H.villosa genome, with the same Yangmai 23 genetic background, will be constructed. After agronomic evaluation, those translocation lines with upgraded agronomic traits compared to Yangmai 23 will be proposed to wheat breeding program. In this project, a wheat-H. villosa comparative physical map will also be constructed based on the sequence information provided by the wheat EST-bin map and the translocation breakpoints. Some important agronomic genes of H.villosa will be mapped to the breakpoint intervals in the H.villosa physical map. The wheat-H.villosa compensating translocation bank constructed in this project will become a basic information platform for efficient finding, physical mapping, and breeding utilization of all kinds of functional genes of H. villosa. It will also give a high-throughput genetic research mode for other wheat related specieses.

簇毛麦是小麦遗传改良重要基因资源。目前簇毛麦遗传研究主要集中于抗病基因，而对其农艺基因研究较少。本项目在小麦-簇毛麦1V-7V染色体代换系基础上，通过构建同背景（扬麦23）的小麦-簇毛麦1V-7V单染色体置换系，以探明簇毛麦不同染色体的农艺效应。利用扬麦23背景的ph1b突变体分别诱导1V-7V与小麦染色体间的易位，并综合运用簇毛麦物种特异性分子标记及1V-7V单染色体双末端标记高通量筛选小麦-簇毛麦易位系，构建覆盖簇毛麦全基因组、扬麦23为背景的补偿性易位染色体库。通过易位系的农艺评价，完成易位片段农艺效应分析。利用普通小麦EST-bin图谱构建基于易位断裂点的小麦-簇毛麦比较物理图，并对部分重要农艺基因进行物理定位。本项目构建的"小麦-簇毛麦同背景补偿性易位染色体库"，将为簇毛麦各类有益基因的发掘、定位和育种利用提供一个基础信息平台，也将为小麦近缘种提供一种高通量遗传研究模式。

簇毛麦是小麦近缘种，具有丰富的抗病、抗逆、优质等基因，将簇毛麦优异基因导入到普通小麦对于小麦育种具有重要意义。本项目旨在构建以强筋小麦扬麦23为遗传背景的小麦-簇毛麦易位染色体库，发掘、定位、克隆簇毛麦优异基因，为小麦育种提供重要的分子元件。.已取得进展情况：（1）创制扬麦23为背景的全套簇毛麦单染色单体置换系和全套小簇麦Robertson易位系；完成扬麦23遗传背景的ph1b突变体的转育；研发小簇麦易位染色体系高通量检测方法“双末端标记法”，解决了传统细胞学鉴定方法效率低下、成本较高、信息量少的弊端；诱导获得丰富的小簇麦易位系；通过标记辅助聚合抗白粉病Pm21、PmV和抗黄花叶病基因Wss1，育成多个多抗聚合新品系。（2）根据Pm21基因启动子序列成功开发育种实用型标记MBH1，实现了早代鉴别纯合抗性单株，提高了育种效率。（3）在RIL群体基础上结合35k芯片技术和BAS分析方法，获得2个对结实性有显著正向效应的QTL，分别位于簇毛麦6VS-MBH1a和小麦6DL-2-S2144附近，发现6V#2S对小麦穗数有不利影响，得到含PmV基因的优异重组体T6V#4S-6V#2S.6AL，将促进PmV基因的育种利用。（4）簇毛麦抗白粉病基因Pm21精细定位和克隆获得重要进展。由于感病簇毛麦的发现，实现了Pm21基因在二倍体水平上的精细定位，并通过转基因、突变体、基因沉默、小种鉴定实现了功能验证。Pm21基因的成功克隆是小麦野生资源抗病基因克隆研究的里程碑事件，国内著名公众号BioArt以“重要进展：我国科学家克隆广谱抗白粉病基因Pm21”为题进行了报道。.上述研究成果为簇毛麦新基因的发掘和利用奠定了基础，开发的育种实用型分子标记为标记辅助育种工作提供了技术支撑，发掘与定位的高结实性QTL以及Pm21基因的成功克隆为小麦分子育种提供了众多的分子元件。