利用缺失突变体研究小麦高分子量谷蛋白表达调控相关转录因子

High molecular weight glutenin subunits (HMW-GSs) are a type of the most important seed storage proteins of wheat, due to their significant effects on wheat unique processing quality. They are critical in determining dough elasticity. HMW-GSs are genetically constant in wheat cultivars, while their expression can be easily changed by multiple environmental factors, indicating the presence of upstream genetic regulators that affects HMW-GS expression levels in seeds. Our previous results indicated that the processing parameters, such as protein content, gluten content, zeleny sedimentation volume and the relative and absolute contents of HMW-GSs, were significantly different, when growing the wheat cultivar "shumai 482" in different types of ecological environments for two years. And We have created HMW-GS knockout mutants for shumai482. This Project will (1) firstly grow "shumai 482" and its HMW-GS mutants in typical ecological environments with different levels of processing quality; (2) secondly isolate candidate transcription factor genes by transcriptome analyses of differentially expressed genes in developing seeds; (3) thirdly characterize the function of candidate transcription factor genes, by using yeast hybrid analysis, RT-Q-PCR, gel retardation assay, chromatin immunoprecipitation assay, transgenic research and some other classic techniques. Based on these findings, we can clarify the contribution of some transcription factors to wheat flour quality, and provide key genes for further imporvement of wheat processing quality by breeding.

高分子量谷蛋白（HMW-GS）决定小麦面团的弹性，对加工品质起重要作用。小麦品种HMW-GS组成稳定，但其含量易受环境影响，这表明有上游调控因子影响HMW-GS表达。我们前期创制了小麦品种蜀麦482的整套HMW-GS缺失系；前期多年多点实验证明在不同生态条件下蜀麦482的蛋白质含量、面筋含量、沉降值、HMW-GS含量等存在显著差异。本项目拟在加工品质差异极显著的生态点种植蜀麦482及其HMW-GS缺失突变体，利用表达谱分析生态点间和材料间的差异表达基因，筛选调节HMW-GS表达的候选转录因子，然后利用酵母杂交、RT-Q-PCR、凝胶阻滞实验、染色体免疫共沉淀、转基因等经典方法鉴定转录因子并验证其功能。在此基础上分析转录因子通过调控HMW-GS表达影响小麦加工品质的分子机理，为小麦加工品质的遗传改良提供关键基因。

高分子量谷蛋白（HMW-GS）决定小麦面团的弹性，对加工品质起重要作用。小麦品种HMW-GS组成稳定，但其含量易受环境影响，这表明有上游调控因子影响HMW-GS表达。本项目通过表达谱分析、遗传分析和酵母单杂交等经典技术鉴定了三个可调控HMW-GS表达的转录因子基因/等位变异 Qc1、bHLH33和Qc5，并证明Qc1可增加维管束数量，提高有机物的运输效率，具有保产提质的潜在价值；bHLH33可结合HMW-GS启动子，激活其转录；Qc5可通过影响种子储藏蛋白在籽粒的分布，通过调控谷蛋白基因的表达提升面包品质。基于以上结果，可进一步挖掘优异等位变异，应用于小麦品质育种，提升我国小麦品质。