基于SSR标记的杨树新品种鉴定及核心引物筛选

Identification of new Populus varieties and screening of core primers based on SSR markers

【目的】利用经过长期筛选的11对SSR引物对50份杨树新品种(系)进行扩增,探究11对引物的品种鉴定能力和核心引物的筛选依据,为杨树新品种的鉴定、育种工作和核心引物的筛选工作奠定基础。【方法】使用毛细管电泳技术对扩增结果进行检测,计算等位重复序列数、Shannon信息指数和引物多态性信息指数等。按0/1矩阵记录扩增条带的有无,并通过非加权组平均法(UPGMA)进行聚类分析。计算单个引物和11对引物组合的遗传相似系数,分析遗传相似系数之间的相关性,剔除相关性较低的引物,再对剩余的引物组合进行聚类分析。【结果】11对引物共扩增出122个DNA片段,平均每对引物扩增的等位重复序列数为11.091个;不同引物PIC值的变化范围是0.530~0.908,平均值为0.803。11对引物的聚类结果显示,当支距为0.40时,参试样品可以分为2个大类;当支距为0.37时,可分为4个亚类,聚类结果与品种(系)的谱系来源基本吻合。在11对现有引物的基础上,通过分析单个引物和11对引物的遗传相似系数之间的相关性,优化得到9对核心引物。相关性分析和聚类分析表明,优化后的9对引物具有高效鉴定能力和亲缘关系聚类效果。【结论】本研究证实SSR分子标记可以有效鉴定杨树新品种,并较好反映品种之间的亲缘关系;同时,利用遗传相似系数的相关性可优化现有的引物,为杨树的育种及核心引物的筛选工作提供了参考。

[Objective]Eleven pairs of SSR primers being screened for a long time were used to amplify 50 new Populus varieties(clone)in order to explore the cultivar identification ability of SSR markers and the screening basis of core primers,which lays a foundation for the identification,breeding and screening of core primers for new Populus varieties.[Method]Capillary electrophoresis was used to detect the amplified fragments.The number of allelic repeat sequences,Shannon information index,and primer polymorphism information index were calculated based on the electrophoresis.The 0/1 matrix which recorded the absence and the presence of the amplification bands was used for cluster analysis by the unweighted pair-group method with arithmetic means(UPGMA).The genetic similarity coefficients of a single primer and 11 pairs of primer combinations were calculated,and the correlation between the genetic similarity coefficients was analyzed.The primers with low correlation were removed,and then the remaining primers were clustered.[Result]The results showed that a total of 122 DNA fragments were amplified by 11 pairs of primers,and the average number of allelic repeat sequences amplified by each pair of primers was 11.091.The PIC of different primers varied from 0.530 to 0.908,with an average value of 0.803.The clustering results of 11 pairs of primers showed that when the branch distance was 0.40,the samples could be divided into 2 categories;when the branch distance was 0.37,it could be divided into 4 subcategories and the clustering results were basically consistent with the pedigree sources of the new varieties(clone).On the basis of the existing primers,9 pairs of core primers were obtained by analyzing the correlation of the genetic similarity coefficients of individual primers and 11 pairs of primers,which has high-efficiency identification ability and clustering effect of genetic relationship.[Conclusion]This study confirmed that SSR molecular markers could effectively identify new poplar varieties and better reflect the relationship between varieties.Meanwhile,the existing primers could be optimized by the correlation of genetic similarity coefficient,which will provide a reference for poplar breeding and the selection of core primers.