中国大麦地方品种的遗传多样性及α-淀粉酶活性的全基因组关联分析

摘要

[目的]了解中国大麦地方品种的遗传多样性,为大麦α-淀粉酶活性基因寻找有效的分子标记.[方法]利用覆盖全基因组的41对简单重复序列(SSR)标记引物,对257份中国大麦地方品种进行PCR扩增；采用Nei's遗传距离和邻接(neighbour-joining)法进行聚类分析；在对群体结构和连锁不平衡分析的基础上,进行基于全基因组的表型与基因型的关联分析.[结果]共鉴定出709个等位变异,平均每个位点的等位变异数为17个.41个SSR标记位点的多态性信息指数(PI)变化范围为0.23(Bmag 0385)-0.94(Bmac0032),平均为0.6385.257个中国大麦地方品种聚合成9个不同的结构类群,发现5个与大麦α-淀粉酶活性显著关联的标记位点.[结论]中国大麦地方品种中蕴藏着丰富的遗传等位变异；各类群的特性和品种来源符合“遗传关系密切、表型特征特性相同、地理生态相近”的同类群聚集规律.在5个关联位点中,位于7H染色体上的Bmag0385位点,其等位变异A215的酶活增强效应最大；此外,7H上Bmac0273的等位变异A141的增效作用较大,可用于啤酒大麦育种的分子标记辅助选择.%[Objective] The objective of this study is to understand genetic diversity in Chinese barley landraces and screen valuable molecular marker for a-amylase activity.[Method] A total 257 Chinese barley landraces were genotyped with 41 SSR markers distributing on seven chromosomes of barley.Nei's genetic distance and neighbour-joining were adoped in cluster analysis.[Result] A total of 709 alleles were identified at 41 SSR loci in 257 Chinese barley landraces.The number of alleles per locus ranged from 5 to 44,with an average of 17.The polymorphism information content value for SSRs ranged from 0.23 (Bmag 0385) to 0.94(Bmac0032) with a mean of 0.6385.Cluster analysis detected that nine clusters were identified based on Nei's genetic distance in 257 accessions.Association analysis showed that five SSR markers significantly associated with α-amylase activity.[Conclusion] Chinese barley landraces have rich genetic diversity and could be clustered into nine different groups based on morphological characteristics,geographic origin and genetic relationships.Among the five SSR markers associated with α-amylase activity,Bmag0385 on chromosome-7H carrying allele A215 possessed the highest α-amylase activity,and Bmac0273 on 7H carrying with allele A141 had relatively high positive effect on α-amylase activity.All of them could be used in marker-assisted selection for malting barley breeding.