节节麦高分子量谷蛋白Dx5~t+Dy12~t亚基组合中Dy12~t亚基的序列测定与分析

为了认识节节麦5t+12t亚基品质表现突出的分子基础,利用SDS-PAGE分析研究了该亚基组合中12t亚基的电泳迁移率并克隆和测序了该亚基基因。结果表明,该12t亚基在SDS-PAGE上的电泳迁移率与普通小麦中的Dy12具有一致的电泳迁移率,但与Dy10的电泳迁移率差异明显。而氨基酸序列比较结果显示,12t亚基的分子序列与Dy10的相似程度非常高,二者仅存在4个氨基酸的替换,而它与Dy12的分子序列存在较大的差异,不但包括12个氨基酸的替换,同时包括2个六肽氨基酸和另外4个氨基酸部位的插入和缺失变化。本研究结果表明,节节麦高分子量谷蛋白Dx5t+Dy12t亚基赋予小麦优良加工品质的主要原因可能与12t亚基与小麦Dy10非常相似,导致这一亚基组合更倾向与Dx5+Dy10有一定关系。

Characterization of HMW Glutenin Subunit Gene Dy12t from Aegilops tauschii Accession with Subunit Combination Dx5t+Dy12t

To understand the molecular bases for HMW glutenin subunit Dx5t Dy12t endowing wheat flours with prominent end use qualities, the electrophoresis mobility of Dy12t in this subunit combinations was determined by SDS-PAGE analysis and the gene for this subunit was isolated and sequenced. Results showed that the electrophoresis mobility of HMW glutenin Dy12t of Aegilops tauschii and Dy12 of wheat are the same, while both are distinctively different from Dy10 of wheat. However, at amino acid sequence level, HMW glutenin Dy12t differs from Dy10 only by four amino acid replacement, while they showed great difference with Dy12 by twelve amino acid replacements and two hexpeptide insertions and four amino acid insertions/deletions. The results suggested that the main reason for Ae.tauschii HMW glutenin Dx5t Dy12t endowing wheat with good baking quality could ascribe to the high similarity between HMW glutenin Dy12t and Dy10 at amino acid sequence level, which makes the quality potential of HMW glutenin subunit pair Dx5t Dy12t is very like that of Dx5 Dy10.