小麦优质谷蛋白亚基分子标记多重PCR体系的建立与应用

Ax1/Ax2*、Dx5和过量表达的Bx7亚基(Bx7^OE)被认为是对小麦品质有正向效应的优质亚基。根据以上亚基特异性分子标记建立相应的多重PCR体系，经品种和群体检验，证明利用该体系鉴定亚基的结果稳定可靠、成本较低。利用该多重PCR技术对89份西藏小麦育成和推广品种(系)的优质亚基频率进行鉴定，结果表明, Dx5和Ax1/Ax2*亚基的频率均为12.4%，没有检测到Bx7^OE，同时携带两个优质亚基的材料频率为10.1%，该麦区品质育种必须加强优质亚基的引入。针对优质亚基Ax1/Ax2*、Dx5和Bx7^OE的多重PCR体系，为小麦品质育种亲本评价和通过杂交方法聚合优质亚基基因提供了一种实用可靠的标记辅助选择技术。

Establishment and Application of Multiplex-PCR for Wheat Glutenin Subunits Relative to Superior End-Use Quality

Wheat processing qualities are largely dependent on the number and composition of high-molecular-weight glutenin subunits (HMW-GS). It has been demonstrated that Ax1/Ax2*, Dx5, and overexpressed Bx7 (Bx7^OE) are normally associated with superior end-use quality, especially dough strength. So far, Bx7^OE allele has not been exploited widely in China wheat breeding program. With the optimization of reaction components and amplification condition, three pairs of PCR primers targeting for Ax1/Ax2*, Bx7^OE, and Dx5 genes were used to establish a multiplex PCR for the purpose of enhanced molecular marker-assisted breeding with good reliability and low cost. The validation with wheat cultivars (lines) carrying known genes displayed that the developed multiplex PCR permitted the discrimination of these major HMW-GS in a single PCR reaction and agarose gel assay. A total of 89 wheat cultivars and advanced lines from Tibet were tested by the multiplex PCR-based assay. The results showed that each frequency of Ax1/Ax2* and Dx5 was 12.4%, and only 10.1% of the accessions possessed both Ax1/Ax2*and Dx5, whereas no accessions carried Bx7^OE. Introduction of HMW-GS relative to good gluten quality must enhance the improvement of wheat quality in this region.