普通小麦及其3个近缘种中抽穗期基因TaHd1直向同源区进化分析

Heading date is one of the most important agronomic traits of common wheat. It has lived through strict domestication in the origination and evolution of common wheat. By using BAC libraries of Triticum aestivum "Chinese Spring" and its 3 relative species, evolution analysis of TaHd1-orthologous regions will be implemented by means of new generation of high-throughput sequencing technologies combined with bioinformatics analysis and molecular biology experiments. Those are as fellows: ⑴ Investigation of sequence composition, gene structure and alternative splicing, genome size influencing by retrotransposons and its mechanism in the regions. Exploration of the regions is whether or not gene dense region containing several important agronomic traits; ⑵ Detection of gene conservatism and colinearity, species-specific genes, identification and function prediction of conserved non-coding sequence in the regions; ⑶ By means of phylogeny analysis of orthologous genes, combined with the conservatism and colinearity of non-coding sequences in the regions, to explore the phylogenetic relationships of A, B, and D genomes among the four species. The results obtained in this study will be of significance for clarifying the biological problems such as genome segment evolution mechanism, gene and transposon evolution mechanism in TaHd1-orthologous regions, and also for providing valuable reference to exploration and utilization of good genes in the wild relatives of common wheat.

抽穗期是普通小麦最重要的农艺性状之一，其控制基因在普通小麦起源、演化过程中经历过严格的驯化选择。本课题拟以普通小麦及其3个近缘种的基因组BAC文库为材料，采用新一代高通量测序技术结合生物信息学分析及相关分子生物学实验进行抽穗期TaHd1直向同源区序列进化研究，主要有：⑴研究TaHd1直向同源区的序列组成，基因结构与选择性拼接以及逆转座子对基因组区段大小的影响及其机制，探明该区段是否为含有几个重要农艺性状基因的密集区；⑵研究TaHd1直向同源区中基因保守性与共线性，进行物种特有基因鉴定、保守非编码序列鉴定与功能预测；⑶通过直向同源基因系统演化分析结合同源区段中非编码序列保守性与共线性，探索四个物种中A、B、D基因组间的系统发育关系。研究结果将对阐明TaHd1直向同源区区段进化机制、基因及转座子进化机制等生物学问题有重要意义，也将为普通小麦野生近缘资源中优良基因的发掘与利用提供有价值的参考。

抽穗期作为普通小麦重要农艺性状之一，不但直接决定了普通小麦育成品种的推广范围与季节，而且对普通小麦品种的产量、品质、抗逆性等重要性状都有影响。为了阐明普通小麦及其近缘种中抽穗期基因TaHd1直向同源区基因组区段进化机制、基因及转座子进化机制等重要生物学问题，本课题在国家自然科学基金河南人才培养联合基金的资助下进行了普通小麦及其3 个近缘种中抽穗期基因TaHd1 直向同源区进化研究。初步研究结果表明，TaHd1直向同源区属于基因密集区，该8个BAC分布了总计244个预测基因，基因平均密度为0.26个/kb (3.95kb/gene)；同源区中存在可能由逆转座子介导的大片段DNA插入或缺失，并可能导致一些抗性基因在普通小麦中丧失；同源区中存在SNP/INDEL成簇分布现象这可能与TaHd1等基因的广阔地域适应性有关；小麦B基因组与拟斯卑尔脱山羊草亲缘关系较近。研究结果为普通小麦野生近缘资源中优良基因的发掘与利用提供有价值的参考。