小麦Wx-A1和Wx-D1位点的PCR分子标记

为了获得筛选低直链淀粉含量的分子标记,根据已知小麦Waxy基因序列设计PCR引物,通过在基因水平和蛋白质水平进行分离群体验证,建立分别专一检测Wx-A1位点和Wx-D1位点的PCR标记MAG264和MAG269。在分离群体中,MAG264标记能清楚地区分Wx-A1位点的三种不同基因型,呈共显性遗传。MAG269标记引物在野生型中扩增片段为1 400 bp,在突变型(Wx-D1bWx-D1b)中的扩增片段为800bp。但在分离群体中没有出现杂合体带型,从而使本应该表现为共显性的标记表现为显性遗传。MAG264和MAG269引物对DNA的扩增稳定性、重复性好。这些结果表明,本研究获得的Waxy基因分子标记可以用于小麦Waxy基因缺失类型的鉴定和糯质专用小麦的分子标记辅助选育。

PCR-based Molecular Markers for Wx-A1 and Wx-D1 Genes of Wheat

To develop molecular markers for low amylose content of wheat, two PCR-based markers, MAG264 and MAG269, specific for loci Wx-A1 and Wx-D1, respectively, were designed based on the known sequences of Waxy genes and validated both at the nucleotide and protein levels using segregating populations. Marker MAG264, inherited in a co-dominant manner, can distinguish all three genotypes of the Wx-Al locus from each other. The primers of marker MAG269 amplified a 1400 bp band in the wild type of the Wx-D1 locus, a 800bp band in the mutant genotype (Wx-D1b Wx-D1b) and the heterozygous genotypes, which made the should-be co-dominant marker MAG269 appear like a dominant one. Having good stability and repeatability in amplifying genomic DNA, these two PCR-based markers are useful for identifying wheat cultivars with Wx-A1b and Wx-D1b alleles, respectively.