普通小麦醇溶蛋白表达特征与Gli-A2座位调控面筋功能和面包烘烤品质的研究

Gliadin proteins constitute a large family of seed storage proteins affecting the processing quality of common wheat. However, the high complexities of gliadins, caused by multiple chromosome loci and gene copies and extensive allelic variation, have often hampered their genetic and functional studies. To facilitate genetic and functional studies of gliadins in common wheat, we have developed a set of deletion mutants lacking three Gli-1 (Gli-A1、Gli-B1 and Gli-D1) and three Gli-2 (Gli-A2、Gli-B2 and Gli-D2) loci, respectively, by screening an ion beam mutagenized population of the winter variety Xiaoyan 81. On the basis of the above work, this application aims 1) to study the expression characteristics of gliadin genes at the transcriptome level, 2) to establish correspondence between gliadin transcripts and the gliadins accumulated in the seeds and to assign the expressed gliadin gene members to individual Gli loci, 3) to determine the genomic sequence and gene composition of Gli-A2 and to analyze the regulation of gluten functionality and bread-making quality by this locus using deletion mutants. Our investiagtion will generate new knowledge on the expression and function of gliadin loci and genes, which may provide useful guidance for further studies of gliadins and genetic improvement of processing quality in common wheat.

醇溶蛋白是影响小麦加工品质的重要因素，其染色体座位的复杂性、基因成员的多重性及广泛等位变异给深入认识醇溶蛋白调控加工品质的功能和机理带来困难。我们筛选小偃81离子束诱变群体获得三个Gli-1（Gli-A1、Gli-B1和Gli-D1）和三个 Gli-2（Gli-A2、Gli-B2和Gli-D2）位点的醇溶蛋白染色体座位缺失突变体。在此基础上，本申请拟研究如下。1）在转录水平上，鉴定活跃转录的醇溶蛋白基因成员。2）将活跃转录的醇溶蛋白基因与其表达产物对应并定位到相应染色体座位。3）以Gli-A2为代表，通过DNA测序阐明其座位结构，利用完整和部分缺失突变体揭示该座位对面筋功能参数和面包烘烤品质的影响。本研究可为深入认识醇溶蛋白基因家族的表达特征及Gli-A2位点调控面筋与面包烘烤品质的功能增添新知识，对于全面剖析醇溶蛋白基因座位的结构、功能及小麦加工品质的分子改良具有重要指导意义和实用价值。

醇溶蛋白是影响小麦加工品质的重要因素，其染色体座位的复杂性、基因成员的多重性及广泛等位变异给深入认识醇溶蛋白调控加工品质的功能和机理带来困难。本实验室拥有小偃81离子束诱变群体获得的三个 Gli-2（Gli-A2、Gli-B2和Gli-D2）位点的醇溶蛋白染色体座位缺失突变体，可以很好的用来研究醇溶蛋白基因与加工品质的关系。.本项目通过转录组水平上鉴定出活跃表达的醇溶蛋白基因，再进一步通过筛选BAC克隆的方法，对Gli-2位点的阳性BAC克隆测序，获得了比较完整的Gli-2位点的基因座位结构，从而确定了缺失突变体缺失的醇溶蛋白基因。多年多点数据表明，DLGliA2c小穗稀疏、分蘖数少，而且籽粒灌浆不充分; DLGliB2有部分花粉败育特性。野生型小偃81和Gli-D2缺失系（DLGliD2）在株高、生育期以及籽粒产量等方面没有显著差别，但DLGliD2的面筋、面团、面包加工品质以及籽粒赖氨酸含量显著优于小偃81。利用分子标记辅助选择将Gli-D2的缺失变异转入强筋小麦品种郑麦366，可进一步提高其面筋与面团功能指标以及面包加工品质。.本研究可为深入认识醇溶蛋白基因家族的表达特征及Gli-2位点调控面筋与面包烘烤品质的功能增添新知识，对于全面剖析醇溶蛋白基因座位的结构、功能及小麦加工品质的分子改良具有重要指导意义和实用价值。