小麦近缘植物冰草遗传图谱构建与优异基因发掘

The genus Agropyron Gaertn. (also known as the crested wheat grass complex), the wild relatives of wheat (Triticum aestivum L.), is composed of a series of diploid (2n = 14), tetraploid (2n = 28), and hexaploid (2n = 42) species having the P genome. Agropyron species have many useful traits, such as tolerance to low temperature and salinity, and resistance to rusts, head scab, and other pathogens of wheat, also possess the desirable genes exhibiting good yield-related traits, such as high grain number per spike, high spikelet number per spike and high tiller number. Thus the Agropyron species have been using as valuable resources for the improvement of wheat. The project team in the success of distant hybridization of wheat-Agropyron cristatum, has created abundant progeny materials having desirable traits from the tiny P chromosomal fragments transferred into wheat, and got a large number of wheat-Agropyron alien translocation lines and infiltration lines. Because of the lack of high-density genetic map of the P genome, it limits the efficiency of detecting, tracing and utilization of the P genome excellent gene in wheat. On the basis of establishing cross-pollination CP population developed from hybrid F1 between A. mongolicum and diploid A cristatum, the research aims to construct the high-density genetic map of P genome using simple genome sequencing and high-throughput SNP development; to map and excavate new genes of the P genome; to clarify the genes/QTLs genetic effect of important properties in control of yield in the P genome; and to develop the molecular markers used for breeding assisted selection. The research would establish a scientific basis for P genome elite gene identification and effective utilization in wheat breeding, and lay a foundation for the research and application of comparative genomics in the Triticeae.

冰草属（Agropyron Gaertn.）植物是小麦族中基因组为P组的野生近缘植物，冰草属P基因组作为多种优异外源基因供体，对于小麦抗病、逆性尤其是产量性状的遗传改良具有重要意义。本项目组在成功进行小麦-冰草远缘杂交的基础上,已将携带冰草优异特性的染色体小片段转移到小麦中,获得一大批小麦-冰草易位系和渗入系。由于缺乏P基因组高密度遗传图谱，限制了小麦中P基因组优异基因的鉴定、追踪和利用效率。本研究在利用蒙古冰草A. mongolicum和二倍体冰草A. cristatum 建立异花授粉CP群体的基础上，采用简单基因组测序和高通量SNP开发，构建冰草高密度遗传图谱，对P基因组新基因进行定位和发掘，阐明P基因组控制产量等重要性状基因/QTL的遗传效应，开发用于辅助选择的分子标记。为冰草P基因组优异基因的鉴定及其在小麦育种中的有效利用提供科学依据；为小麦族植物比较基因组学的研究与应用奠定基础。

冰草（Agropyron Gaertn.）是具有P基因组的小麦野生近缘植物，冰草P基因组具有抗病、抗逆、丰产等多种优异基因，对冰草P基因组进行遗传图谱构建和优异基因发掘对于利用冰草优异基因十分重要。项目主要内容包括：冰草P基因组遗传群体的基因型鉴定，遗传群体中重要性状的表型鉴定，P基因组遗传图谱构建，主要性状基因（QTL）定位，冰草重要性状基因的分子标记开发。主要结果：对冰草CP群体进行了多年多点的农艺性状调查，利用SLAF-seq技术对冰草CP群体F1及亲本简化基因组测序获得数据开发的SNP标记进行连锁分析和构建图谱，得到7个连锁群，上图标记1754个，总图距2358.6cM，平均图距1.35cM。对冰草P基因组控制茎、穗等主要性状进行QTL分析，阐明了6个主要性状的QTL位点。解析了不同环境下控制小穗数、穗长等QTL，检测到7个稳定QTL。开发位于2P、3P、4P、5P、7P染色体解释表型变异超过10%可用于辅助选择的分子标记8个。利用小麦-冰草易位系分离群体定位抗白粉病和叶锈病新基因2个，开发用于追踪携带冰草P染色体抗病基因片段的分子标记11个。发表SCI论文5篇。上述研究为利用冰草P基因组基因改良小麦提供了理论指导和科学依据。