人工合成六倍体小麦与普通小麦杂交后代衍生群体的PPO基因分析

Genetic Detection of PPO Gene in Synthetic Hexaploid Wheat-Derived Populations

四倍体小麦与节节麦杂交培育的人工合成六倍体小麦已广泛应用于国内外小麦品种改良。以引自CIMMYT的Syn768、Syn769、Syn780和Syn786人工合成六倍体小麦分别与中国四川成都平原主栽普通小麦品种杂交、回交的BC2F2:6后代群体中选育的113份优良高代系和川麦38、川麦42、川麦43和川麦47育成品种为材料,采用SSR特异引物Xgwm312标记位点的PAGE凝胶电泳对其PPO基因型进行了研究。结果表明,Xgwm312位点的标记具有多态性,其PCR扩增产物可产生198bp、216bp、232bp和240bp四种等位基因变异片段。在所检测的117份后代衍生群体材料中,65份材料具有198bp片段的等位基因,占全部材料的55.56%;13份含216bp片段的等位基因,其频率为11.11%,35份材料具有232bp片段的等位基因,分布频率为29.91%;只有4份材料含有240bp片段的等位基因,仅占全部材料的3.42%。从每个人工合成六倍体小麦亲本材料所形成的后代衍生群体来看,基因等位变异片段分布频率各不相同。说明PPO基因在小麦杂交后代材料中基因型的表现存在着随机性,与亲本的基因型状况关系极大,并且在后代材料中出现了亲本都没有的240bp等位基因变异片段的材料。通过研究人工合成六倍体小麦与普通小麦杂交后代的PPO基因型,有助于提高分子标记育种效率,也有助于PPO基因型的多态性研究,并为人工合成六倍体小麦在我国小麦品种改良和分子标记育种中的应用提供依据和方法。

Synthetic hexaploid wheats, obtained by crossing tetraploid wheats （AABB） with Aegilops tauschii Coss （DD）, containing genetic variability different from bread wheat, now have been widely used for genetic improvement of bread wheat. A total of 113 BC2F2：6 advanced lines and 4 commercial cultivars derived from four CIMMYT synthetic hexaploid wheats, Syn768, Syn769, Syn780 and Syn786, were used to detect PPO genotype by specific-primer PCR amplification and modified PAGE. The results showed that the SSR marker at Xgwm312 locus for the 117 synthetic derived cultivars and advanced lines produced four polymorphic fragments with alleles of 198bp, 216bp, 232bp and 240bp. Of 113 lines, there were 65 with 198bp allelic fragment, 13 with 216bp allelic fragment, 35 with 232bp allelic fragment and 4 with 240bp allelic fragment. The allelic fragment distributional frequencies were different between the four synthetic derived advanced line populations. The results revealed that PPO gene is randomly segregated into offspring and significantly relative to parental genotypes. A novel variation with 240bp allelic fragment which was not existed in the parents was observed in present experiment. From this study, it could be concluded that the study on PPO genotype of progeny from crosses of synthetic hexaploid wheat and bread wheat can provide useful information for improving bread wheat.