蚕豆SSR标记遗传多样性及与淀粉含量的关联分析

Genetic diversity and its association analysis of SSR markers with starch content in faba bean(Vicia faba L.)

淀粉是蚕豆籽粒碳水化合物中含量最丰富的一类。淀粉含量会影响其物理和化学性质,从而影响蚕豆的品质和用途。了解蚕豆品种的遗传多样性,寻找与蚕豆淀粉含量紧密连锁的分子标记,对蚕豆分子标记辅助育种具有重要意义。本研究以260份蚕豆种质为供试材料,测定了2019和2020两年的总淀粉含量、直链淀粉含量和支链淀粉含量。利用具有显著多态性的132对SSR标记对260份蚕豆材料进行遗传多样性分析与群体遗传结构分析,并采用Tassel2.1软件的GLM和MLM两种模型进行标记与淀粉含量的关联分析。结果显示,表型性状的变异系数变幅为13.21%~20.52%,平均值为14.85%,表明供试群体具有一定的表型多样性。132个标记在260份蚕豆材料中共检测到629个多态性位点,各位点的平均等位基因数为4.77个,变异范围为2~11个。多态性信息量(PIC)值在0.0385~0.7772之间,平均为0.4935,PIC值大于平均数的约占50%,表明本研究选用标记基因多样性较高。聚类分析将260份材料划分为3个类群,第Ⅰ类群包括42份材料,第Ⅱ类群包括59份材料,第Ⅲ类群包括159份材料,划分结果体现了蚕豆品种间的亲缘关系。群体遗传结构分析将260份材料划分为2个亚群,表明供试群体结构相对单一,有利于关联分析。基于GLM和MLM模型, 2年均分别检测到8个与总淀粉、直链淀粉和支链淀粉含量极显著(P<0.01)的关联标记,单个标记对表型变异的解释率分别为4.54%~9.04%和2.69%~10.39%。SSR-10927标记与支链淀粉含量在2年和2种模型中均显著(P<0.05)关联,且与总淀粉含量在2019年中的2种模型及2020年的MLM模型中显著(P<0.05)关联,检出率最高。此研究结果为蚕豆分子标记辅助选择育种以及亲本材料选配奠定了理论基础。

Starch is the most abundant type of carbohydrate in faba bean grain.In general,starch content affects its physical and chemical properties,thereby affecting the quality and the use of faba bean.Understanding the genetic diversity of faba bean varie-ties and finding molecular markers closely linked to faba bean starch content are of great significance to the molecular marker-assisted(MAS)breeding of faba bean.In this study,260 accessions of faba bean germplasm were used as test materials to determine the total starch content,amylose content and amylopectin content in 2019 and 2020.To analyze the genetic diversity and population genetic structure of 260 accessions of faba bean materials,the GLM and MLM models of Tassel 2.1 software were used to analyze the association between markers and starch content using 132 pairs of SSR markers with significant polymorphism.The results showed that the coefficient of phenotypic variation ranged from 13.21%to 20.52%with an average value of 14.85%,indicating that the test population had a certain phenotypic diversity.A total of 629 polymorphic locus were de-tected by 132 markers in 260 accessions of faba bean materials.The average number of alleles at each site was 4.77,and the range of variation was 2-11.The value of polymorphism information(PIC)was between 0.0385 and 0.7772,with an average of 0.4935.About 50%of the PIC values were greater than the average,indicating that the diversity of markers used in this study was rela-tively high.Cluster analysis divided 260 materials into three groups.Group I included 42 materials,Group II included 59 materi-als,and Group III included 159 materials.The classification results reflected the genetic relationship between faba bean varieties.The population genetic structure analysis divided 260 materials into two subgroups,indicating that the test population structure was relatively simple,which was conducive to association analysis.Based on the GLM model and the MLM model,eight markers significantly(P<0.01)associated with the content of total starch,amylose and amylopectin were detected in two years respec-tively.The explanation rates of single markers for phenotypic variation were 4.54%-9.04%and 2.69%-10.39%,respectively.The SSR-10927 marker was significantly(P<0.05)associated with amylopectin content in two years and in both models,and was significantly(P<0.05)associated with the total starch content in the two models in 2019 and the MLM model in 2020 with the highest detection rate.The results of this study laid a theoretical foundation for faba bean MAS breeding and the selection of pa-rental materials.