【作者】 韩畅；

【导师】 颜泽洪；

【作者基本信息】 四川农业大学 ， 作物遗传育种， 2009， 硕士

【摘要】 小麦低分子量谷蛋白是重要的种子贮藏蛋白,与加工品质密切相关。在普通小麦中分离了大量的低分子量谷蛋白基因,然而在小麦近缘属中得到的同源蛋白基因还比较有限,限制了对这些基因的研究和利用。本研究通过对GenBank数据库中已有的低分子量谷蛋白基因序列进行分析,设计了一系列PCR引物,通过这些引物组合在小麦近缘属带芒草属中进行扩增,通过克隆和测序,获得了它的低分子量谷蛋白基因,主要结果如下:1.获得了45个低分子量谷蛋白基因序列,其中,33个具有完整的开放阅读框,可正常表达为相应的蛋白质;12个序列由于编码区内含有提前终止密码子或单碱基插入引起移码突变而不能正常表达相应的蛋白质而推测为假基因。这些基因序列的核苷酸和氨基酸长度分别在909-1059bp以及302-351个氨基酸残基之间变化。2.这些基因具有与小麦LMW-m型低分子量谷蛋白基因相似的典型基本结构,根据N端氨基酸序列,这些基因又可以分为METSCIP-和METSRVP-两种类型。3.进化分析表明,带芒草属METSCIP-型低分子量谷蛋白基因与小麦B和D基因组的同源基因聚在一起;METSRVP-型低分子量谷蛋白基因与小麦D基因组同源基因聚在一起。表明带芒草属与小麦的低分子量谷蛋白基因之间非常相似。更多还原

【Abstract】 The low-molecular-weight glutenin subunits(LMW-GS) were the main storage proteins in the wheat seed endosperm.They palyed critical role in determining the enduse quality of wheat flours.Up to now,a large number of LMW-GS genes were isolated and characterized from hexaploid wheat and their diploid donor species.However,limited homologous gene sequence was obtained from its wild relative species.This status hindered us understanding and utilization of these LMW-GS genes for wheat processing properties improvement.In this disseration,we described isolation and characterization of forty-five LMW-GS gene sequences from a wheat wild relatives Taeniatherum using a set of oligonucleotide PCR primers based on the homologous gene from GenBank database. The main results were as follows.(1).A total of 45 LMW-GS sequences were obtained from Taeniatherum.Among them,33 sequences were putative genes by having complete open reading frames and the remaining 12 sequences were putative pseudogenes by inframe stop codons or by frame shift matations.These gene sequences varied from 909 to 1059bp in nucleotide length and 302 to 351 residues in amino acid lengths,respectively.(2).These gene sequences shared the same typical primary structures with those of LMW-m type homologous genes from wheat and characterized by four domains,a signal peptide with 20 amino acid residues,a N terminal with 13 amino acid residues,a lager repetitive domain with repetitive motif unit and a C-terminal domain.According to the N-termianl sequences,these genes can be sub classfied as METSCIP-and METSRVP-types.(3).Sequence alignment showed the main differences and the relationships between LMW-GS genes from wheat and Taeniatherum.Phylogenetic analysis showed that the genes of Taeniatherum with N-terminal sequences of METSCIP-were cluster together with those of homologous genes from B and D genome of wheat;while those of Taeniatherum genes with N-terminal sequences of METSRVP-were cluster together with those of D genome encoded genes of wheat,suggesting that the LMW-GS genes from Taeniatherum were very similar to the genes from wheat.更多还原