摘要
【目的】揭示小麦不同品种Glu-A3位点低分子量麦谷蛋白亚基(LMW-GS)基因的分子特征,寻找在小麦品质改良方面有潜在应用价值的优质候选基因。【方法】选用小麦Glu-A3位点LMW-GS基因特异引物,以中国优质小麦品种小偃6号、陕优225,澳大利亚面包小麦Suneca、Cook以及遗传背景已揭示清楚的中国春小麦为材料,通过基因组特异PCR方法克隆其Glu-A3位点LMW-GS基因,并进行了分子特征比较。【结果】获得了5个Glu-A3位点LMW-GS基因,分别命名为:CookGlu-A3(登录号为EU871816)、XYGlu-A3(FJ876820)、SYGlu-A3(FJ876819)、SunecaGlu-A3(FJ876822)和CSGlu-A3(FJ876821),这5个基因均有完整的ORF、上游197bp的启动子区和终止密码子下游51bp序列,推导蛋白均属于LMW-i型亚基,其差别在于不同序列之间存在着一些SNP位点和插入/缺失片段。其中,CookGlu-A3推导蛋白含7个Cys残基,在C端区缺失了包含第7个保守Cys残基在内的38个氨基酸片段。基于51个染色体位点已知的LMW-GS基因编码区序列比对结果构建的系统发生树,将这些序列分为3大类:所有Glu-A3位点LMW-GS基因编码序列单独聚为第Ⅰ类;部分Glu-D3位点基因被聚在第Ⅱ类;剩余Glu-D3位点基因和全部Glu-B3位点基因被聚在第Ⅲ类,而在第Ⅲ类中这2个位点的LMW-GS基因又各自聚为2个不同的亚类,即Ⅲ-1和Ⅲ-2。【结论】从小麦品种Cook中克隆的CookGlu-A3是编码含7个Cys残基的LMW-i型亚基基因,可能是一个新的LMW-GS基因类型;不同染色体位点的LMW-GS基因在其编码区存在特异性;Glu-A3位点LMW-GS基因与Glu-B3或Glu-D3位点LMW-GS基因编码区序列差异较大。
[ Objective ] The objective of this study was to reveal the molecular characteristics of LMW-GS genes at Glu-A3 locus in different wheat cultivars, and to find candidate genes with potential value in wheat quality improvement. [Method] Chinese wheat cultivars Xiaoyan 6, Shaanyou 225, and Australian bread wheat cultivars Suneca and Cook, as well as Chinese Spring were selected as materials to clone and characterize LMW-GS genes at Glu-A3 locus with the specific primer by PCR in this investigation. [Result] Five LMW-GSgenes at Glu-A3 locus were cloned, named as CookGlu-A3 （accession number EU871816）, XYGlu-A3 （FJ876820）, SYGlu-A3 （FJ876819）, SunecaGlu-A3 （FJ876822）, CSGlu-A3 （FJ876821）. All of them contained the entire coding regions, 197 bp of promoter sequences and 51 bp downstream sequences after stop codons. The differences among the five genes were that there existed some SNPs and insertions/deletions. All the deduced proteins of the five genes belong to LMW-i type. Notablely, the deduced protein of CookGlu-A3 contained 7 cysteline residues, with a 38 aa fragment in the C-terminal domain including the 7th conserved Cys residue missing. On the basis of the similarity of coding sequence, 51 known LMW-GS genes were classified into three groups, and each group was corresponding to a specific locus Glu-A3, Glu-B3 or Glu-D3, respectively. [ Conclusion ] CookGlu-A3 encoded a LMW-i type glutenin subunit with 7 cysteine residues, and it may be a novel LMW-GS gene.All LMW-GS genes at different chromosomal locations had their own specific characteristics in their coding sequences. The coding sequences of the LMW-GS genes at locus Glu-A3 had less identity with those at locus Glu-B3 or Glu-D3.
出处
《中国农业科学》
CAS
CSCD
北大核心
2010年第5期881-888,共8页
Scientia Agricultura Sinica
基金
国家自然科学基金项目(30871578)
转基因重大专项课题(2008ZX08002-004)
