中文摘要：

[目的]旨在从野生二粒小麦中克隆新的低分子量谷蛋白亚基基因.[方法]首先通过SDS-PAGE方法对野生二粒小麦Y5和Y13的低分子量谷蛋白亚基（LMW-GS）进行鉴定,并利用基质辅助激光解析电离飞行时间质谱（MALDI-TOF-MS）方法确定其精确分子量.然后采用AS-PCR方法,运用1对LMW-GS特异的引物,分别从Y5和Y13中扩增并克隆了2个亚基的编码基因（命名为LMW-Y5和LMW-Y13）.[结果]测序结果表明,所得基因均为完整的基因序列,包括上游区域、开放阅读框和下游区域,无内含子存在.由核酸序列所推导出的氨基酸序列表明,这两个基因的编码蛋白（命名为LMW-Y5和LMW-Y13）均属于LMW-i型亚基,分子量分别为38.9122 kD和31.8708 kD.其中LMW-Y5的分子量与质谱鉴定的分子量基本一致,表明该蛋白亚基没有翻译后修饰存在.但LMW-Y13的分子量与SDS-PAGE和质谱鉴定结果存在较大差异,其原因可能是在克隆过程中发生了重复区的碱基丢失.[结论]明确了野生二粒小麦两个LMW-i型亚基的分子结构特征,并讨论了LMW-i型亚基分子结构与品质的关系以及在小麦品质改良中的应用潜力.

英文摘要：

[Objective] The objective of this study was to clone new genes coding for LMW-GS from Triticum dicoccoides （AABB, 2n--4x=28）. [Method] First, SDS-PAGE were used to identify low molecular weight glutenin subunits （LMW-GS） in two Triticum dicoccoides Y5 and Y13. Then matrix-assisted laser desorption ionization time of flight mass spectrometry （MALDI-TOF-MS） was used to determine accurate molecular weights of the LMW-GS. Gene coding for two LMW-GS, named LMW-Y5 and LMW-Y13, were amplified and cloned from Y5 and Y13 respectively, using AS-PCR method and one pair of primers specific to LMW-GS. [Result] Two complete gene sequences were obtained, which comprised of upstream, open reading frame （ORF） and downstream, and no introns were present. The deduced amino acid sequences showed that both the two protein （named LMW-Y5 and LMW-Y13） coding by LMW-Y5 and LMW-YI3 belonged to the LMW-i type subunits with the estimated molecular weight 38.9122kDa and 31.8708kDa. The molecular weight of LMW-Y5 was consistent with the Mrs identified by MALDI-TOF-MS, suggesting that there were no types of protein translational modifications （PTMs） in this subunit. However, the Mrs of LMW-Y13 deduced by DNA sequences was 7.6827kDa lower than that from MS, which may result from a single deletion of about 200bp occurred within the repetitive domain of the recombinant clones. [Conclusion] Molecular structures of LMW-i type subunits in Triticum dicoccoides were first reported in this article. In addition, the relationships between the molecular structures and functions of LMW-i type genes and their potential for wheat quality improvement were also discussed.