不同品质类型小麦籽粒麦谷蛋白亚基及谷蛋白聚合体形成和累积动态

选用高分子量麦谷蛋白亚基(HMW-GS)组成不同的3个强筋和4个弱筋小麦品种,研究了其籽粒发育过程中麦谷蛋白亚基、谷蛋白聚合体的形成和累积动态。结果表明,强筋小麦籽粒HMW-GS和B区低分子量麦谷蛋白亚基(LMW-GS)从花后9～12d开始表达;而弱筋小麦从花后12～15d开始表达,即强筋小麦麦谷蛋白亚基开始形成时间早于弱筋小麦。各品种的HMW-GS一旦形成,其累积速度较快,花后27d基本达到稳定值,之后维持稳定量;而LMW-GS形成后,累积较慢,直到花后30d左右达到稳定量。3个强筋小麦品种籽粒灌浆期谷蛋白总聚合体百分含量(TGP%)和谷蛋白大聚合体百分含量(GMP%)累积动态趋势基本一致,即在花后12～30d一直持续增加,花后30d至成熟达到最大值并保持稳定水平。4个弱筋小麦TGP%和GMP%累积动态均表现为在花后12～24d(灌浆早中期)形成和持续累积,花后24d至成熟逐渐降低。麦谷蛋白亚基表达模式以及谷蛋白聚合体累积动态的差异可能是导致小麦强筋或弱筋品质形成的关键。

Accumulation Dynamics of Glutenin Subunits and Glutenin Polymer in Wheat Cultivars with Different Qualities during Grain Development

The quality of wheat (Triticum aestivum L.) flour for end use depends on the visco-elastic properties of dough, which are influenced by quantity and quality of the gluten-forming storage proteins of wheat endosperm. Gliadin and glutenin are major components of gluten protein. Dough strength is determined by the capacity of glutenin subunits to form large polymers with different sizes, and the quantity and composition of glutenin polymer influence wheat dough properties. To date, there are few reports on accumulation dynamics of glutenin subunits and glutenin polymer in wheat cultivars with different qualities during grain development. In this study, three strong-gluten and four weak-gluten wheat cultivars with different HMW-GS compositions were used to analyze accumulation dynamics of glutenin subunits and glutenin polymer during grain development. The results showed that HMW-GS and LMW-GS of strong-gluten cultivars initially expressed at 9–12 d after flowering, which were earlier than those of weak-gluten cultivars (12–15 d after flowering). Expression time of glutenin subunits in wheat cultivars with strong-gluten was a little earlier than that in wheat cultivars with weak-gluten. The quantity of HMW-GS in each cultivar rapidly increased during the early period of grain-filling, and kept stable from 27 d after flowering to maturity, however, the quantity of LMW-GS accumulated slowly during the grain-filling period, reaching stable level at 30 d after flowering. In wheat cultivars with strong-gluten, TGP (total glutenin polymer) % and GMP (glutenin macropolymer) % rapidly increased at 12–21 d after flowering and slowly increased during 21–30 d after flowering, and then maintained at the stable level from 30 d after flowering to maturity. However, in weak-gluten cultivars, TGP% and GMP% rapidly increased at 12–24 d after flowing and decreased continuously from 27 d after flowering to maturity. The differences of expression profile and accumulation of glutenin subunits and glutenin polymer between wheat cultivars with strong-gluten and weak-gluten may be the key factors affecting strong-gluten or weak-gluten formation of wheat cultivars.