强筋小麦品质形成的关键调控因子解析及其功能研究

Wheat is one of the most important food crops in the world. The safe production of wheat plays a very important role in the national grain security strategy project of absolute safety for rations. Wheat in China has long been paid great attention to the increase of yield, but neglected the improvement for dough quality, which leads to the large amount import of strong gluten wheat every year. Based on our previous data on the glutenin composition, gene expression pattern and the functional analysis of regulatory factor in Triticum urartu, this study will investigate dynamic accumulation and expression patterns of wheat seed storage protein by using iTRAQ and RNA-Seq technologies. Transcriptome profiling will be performed with developing kernels of representative strong gluten varieties at the key stages of storage protein accumulation, and the network analysis will provide a set of transcription factors affecting storage protein accumulation and strong gluten quality. These transcription factors will be subjected to the over-expression in wheat endosperm, dual luciferase reporter assay and ChIP-PCR analysis to manifest the regulation strength of storage protein gene expression, and the over-expression transformants and mutants in common wheat will facilitate the investigation on the impact of the strong gluten formation and dissect the molecular interaction during the formation of strong gluten quality. The project will screen the key regulatory factors controlling the formation of strong gluten quality and analyze the interaction network of quality formation of high quality wheat, so as to provide a theoretical foundation and technical support for breeding strong gluten wheat varieties, which has important theoretical significance and application value.

小麦是世界上最重要的粮食作物之一，小麦生产在保障“口粮绝对安全”的国家粮食安全战略工程中具有重要的地位。长期以来，我国小麦注重产量的提高，忽略品质的改良，使得每年进口大量强筋小麦。本项目拟在前期对乌拉尔图小麦麦谷蛋白基因座位分析、表达模式及其调控因子研究的基础上，利用iTRAQ和RNA-Seq技术分析小麦籽粒储藏蛋白的动态积累及其编码基因表达模式分析，对代表性强筋小麦品种储藏蛋白积累的关键时期进行转录组测定，通过基因共表达网络分析影响储藏蛋白积累和强筋品质密切相关的转录因子，利用胚乳过表达、双荧光素酶报告基因系统和ChIP-PCR明确调控储藏蛋白基因表达的强弱，并通过基因过表达和突变体等材料研究其对强筋品质形成的影响，解析强筋品质形成的互作网络。项目将探究强筋品质形成的关键调控因子，解析优质小麦品质形成的基因互作网络，为培育强筋小麦新品种奠定理论基础和技术支持，具有重要理论意义和应用前景。

小麦是世界上最重要的粮食作物之一，小麦生产在保障“口粮绝对安全”的国家粮食安全战略中扮演举足轻重的角色。长期以来，我国小麦生产着眼于提高产量，却忽略了品质改良，使得我国被迫陷入每年进口大量强筋小麦的窘境。因此，探究强筋品质形成的关键调控因子，解析优质小麦品质形成的基因互作网络，为培育强筋小麦新品种奠定理论基础和技术支撑，具有重要理论意义和应用前景。项目首先对中国春花后5天、10天、15天、20天和25天的籽粒进行转录组测序，明确了大部分储藏蛋白基因集中在花后15天和20天表达，并且共表达网络分析发现多个代谢途径和这些储藏蛋白基因表达具有类似的表达模式。利用102个品种的58,790个基因及19个品质性状数据对花后10天和花后20天进行权重基因共表达网络分析，分别构建了31和28个基因模块。大量与淀粉及蛋白合成相关的候选调控基因被鉴定到，其中花后10天的turquoise、magenta和red模块分别得到19、4和2个，而花后20天的turquoise和green模块分别得到11和19个。随后的GWAS分析发现，两个时期共检测到与19个性状相关的321个显著关联位点，并通过单倍型分析将范围缩小至164个。结合基因注释、GO注释和连锁不平衡等进行深入分析，最终得到26个关联位点，对应13个候选基因。其中，与储藏蛋白共表达的NAC77、ODORANT1等转录因子作为研究重点。相比野生型的储藏蛋白总含量，ODORANT1过表达株系降低13.38%-35.60%，而ODORANT1 RNA干扰株系升高11.43%-19.35%，且不改变其他重要农艺性状。体内和体外实验均表明，ODORANT1结合在储藏蛋白基因的启动子区并抑制其活性，从而减少储藏蛋白的合成。总之，本项目既促进对小麦蛋白合成及品质形成调控网络的理解和认识，又可挖掘关键调控因子为分子育种研究提供重要基因资源。