Molecular detection and distribution of allelic variations of a gene for yellow pigment content in chinese winter wheat cultivars

Chinese. 【目的】八氢番茄红素合成酶（phytoene synthase，Psy）基因是影响小麦黄色素含量的关键基因，利用分子标记检测中国冬小麦品种（系）Psy-A1基因的等位变异及其与黄色素含量的关系，进一步验证Psy-A1基因分子标记的有效性。【方法】利用7A染色体上Psy-A1基因的分子标记YP7A检测该基因在中国217份冬小麦品种（系）中的等位变异，分析不同等位变异与黄色素含量的相关性及变化趋势。【结果】Psy-A1基因标记YP7A为共显性标记，在高、低黄色素含量的小麦材料中分别扩增出194 bp和231 bp片段，相应的等位基因为Psy-A1a和Psy-A1b（GenBank编号分别为EF600063和EF600064）。在217份冬小麦品种（系）中，含有等位基因Psy-A1a和Psy-A1b的品种（系）分别占62.2%和37.8%，二者黄色素含量平均值差异达到极显著水平（P＜0.01）。其中，北方冬麦区、黄淮冬麦区、长江中下游冬麦区及西南冬麦区Psy-A1a等位基因的分布频率分别为75.0%、72.0%、25.9%和33.3%。【结论】分子标记YP7A可以作为小麦品种黄色素含量选择的辅助工具。

English. [Objective] Phytoene synthase （Psy） gene is a critical gene influencing biosynthetic pathway of yellow pigment （YP） in common wheat. The aims of this study were to detect the allelic variations of Psy-A1 gene in 217 Chinese winter wheat cultivars and lines using the functional marker YP7A developed from the sequence polymorphisms of Psy-A1 gene on chromosome 7A, and to investigate the association between YP content and allelic variations of Psy-A1 gene to evaluate the feasibility of the marker for selecting wheat cultivars with either low or high YP content. [Method] Allelic variations of 217 Chinese winter wheat cultivars from different wheat regions were detected using YP7A. The association between allelic variations of Psy-A1 gene and YP content were investigated. [Result] YP7A, a co-dominant marker ofPsy-A1 gene, can amplify a 194-bp and a 231-bp fragment in the genotypes with Psy-Ala frequently for high YP content and Psy-Alb mostly for low YP content, respectively. Highly significant differences in YP content were detected between the genotypes with Psy-Ala and those with Psy-A1b （P〈0.01）. The occurrence frequencies for Psy-Ala and Psy-Alb were 62.2% and 37.8% in the 217 cultivars, respectively. Significant differences of allelic variations were found in wheat cultivars from different wheat regions of China. In the Northern Winter Wheat Region, Yellow ＆ Huai Winter Wheat Region, the Middle ＆ Lower reaches of the Yangtze River Winter Wheat Region and Southwestern Winter Wheat Region, frequencies of the allele Psy-Ala were 75.0%, 72.0%, 25.9% and 33.3%, respectively. [ Conclusion ] The molecular marker YP7A exhibites the characteristics of high efficiency and reliability in evaluating YP content, and can be used as a molecular tool for marker-assisted selection （MAS） in wheat breeding programs targeting for either low or high YP content.