小麦春化基因新等位变异Vrn-B3d的鉴定

Characterization of a Novel Vernalization Allele Vrn-B3d in Wheat

春化基因的遗传多样性决定了小麦广泛的适应性,挖掘和鉴定春化基因的新等位变异,可为广适小麦育种奠定基础。本研究以普通小麦地方品种和尚头为材料,采用生物信息学和分子克隆手段获得VRN-B3基因,全长3818 bp。与隐性等位变异vrn-B3相比,和尚头中VRN-B3基因在启动子区有一个160 bp的插入片段,为VRN-B3基因的一种新等位变异,暂命名为Vrn-B3d。经PlantCare网站预测,该插入片段包含CAAT-box、G-box和TATA-box三种顺式作用元件。基于Vrn-B3d差异序列,开发一对检测新变异的分子标记,并构建能够同时区分VRN-B3位点5种等位变异的高效多重PCR体系。通过检测262份中国微核心种质资源,发现93.5%的品种携带vrn-B3,5.7%的品种携带Vrn-B3b,并在新疆春麦和红冬麦品种中发现新等位变异Vrn-B3d,说明该变异主要分布在新疆地区。温室表型和基因型相关性分析结果表明,与vrn-B3相比,Vrn-B3d能使小麦推迟两天抽穗。本研究丰富了小麦春化基因遗传变异的多样性,开发了分子标记并构建多重PCR体系,为小麦育种提供了优异种质资源和分子检测有效方法。

The genetic diversity of vernalization genes determines the broad adaptability of wheat.Discovery and characterization of new alleles of vernalization genes can contribute to the wide adaptability of wheat breeding.In this study,a common wheat local germplasm,Heshangtou,was used to reveal the whole sequence of VRN-B3 gene.With the help of bioinformatics and molecular cloning methods,the whole sequence of VRN-B3 was obtained(3818 bp).Compared with the known allelic sequences of the VRN-B3 locus,Heshangtou has a 160 bp insertion in the promoter region,indicating a new allele of the VRN-B3 gene and is temporarily named as Vrn-B3d.The prediction(PlantCare website)showed that the 160 bp insertion contains three cis-acting elements:CAAT-box,G-box and TATA-box.Based on the Vrn-B3d differential sequence,a pair of molecular markers for detecting the new allele was developed,and an efficient multiplex PCR system was constructed to distinguish five alleles at VRN-B3 locus simultaneously.Screening of 262 Chinese micro-core germplasm resources showed that 93.5%cultivars carried vrn-B3;5.7%cultivars carried Vrn-B3b and the novel Vrn-B3d was found in two cultivars(Chunmai and Hongdongmai)of Xinjiang wheat.The correlation analysis between phenotype and genotype showed that Vrn-B3d prolonged heading time by two days compared with those germplasms containing the recessive allele vrn-B3.This study enriched the genetic diversity of vernalization genes in wheat,developed molecular markers and established a multiplex PCR system.These results would provide useful germplasm resources and methods for marker-assisted selection for wheat breeding.