基于表型和ISSR标记滇产黄杨叶栒子遗传多样性分析

目的]从表型和分子2个角度揭示黄杨叶栒子(Cotoneaster buxifolius Lindl.)野生种群的遗传多样性。方法]利用33个表型性状和ISSR分子标记对滇产野生黄杨叶栒子进行了遗传多样性分析。用PopGen 32软件计算多样性指数,用SPSS 16.0软件构建系统发育树系图。结果]黄杨叶栒子种内表型性状在居群间存在着丰富的变异,居群间表型性状叶片大小变异系数达25.99%,萼裂片相关3个性状变异达40.66%,差异较大;24条ISSR引物扩增出228条带,其中,153条具有多态性,平均多态率为81.56%,Nei’s基因多样性指数和Shannon多样性指数分别为0.352 0和0.505 9,具有较高的遗传多样性;采用UPGMA法构建遗传关系聚类图,形态和分子标记的2种聚类结果基本一致:分布在同一地区的各个居群多数能聚在一起,地理位置的隔离促进了黄杨叶栒子居群间的遗传分化;个别居群未能与同一产区的其他居群聚在一起,而聚进了其他产区的居群之中,其原因可能是同一产区内各居群的小生境不完全相同,在不同产区内也有相似的小生境,导致黄杨叶栒子居群间发生了趋同进化。结论]黄杨叶栒子遗传多样性丰富,居群间的亲缘关系及分布与地理位置、海拔位置有密切关系。

Genetic Diversity Analysis of Cotoneaster buxifolius in Yunnan Province Based on Phenotype Characters and ISSR Marker

Objective] To reveal the level of genetic diversity of wild populations of Cotoneaster buxifolius Lindl.from the viewpoints of phenotypic traits and molecular marker. Method] 33 phenotypic traits and ISSR primers were used to investigate the genetic diversity of wild populations of C. buxifolius in Yunnan. The diversity indices were calculated by PopGen software and the phylogenetic trees were constructed by SPSS 16.0 software. Result]The analysis of numeric traits indicated that the average coefficient of variation of leaf length and leaf width was25.99%. The variation of three related traits of calyx lobes was 40.66%, and the difference was significant. In total228 bands were detected by 24 ISSR primers, 153 of them were polymorphic and the percentage of polymorphic bands was 81.56%. The Nei’s gene diversity index was 0.352 0 while the Shannon diversity index was 0.505 9. These data indicated that there was abundant genetic diversity in C. buxifolius. The 2 phylogenetic trees based on phenotypic traits and ISSR markers by UPGMA were similar. Most populations in the same distribution areas were classified into the same group, while a few populations did not combine with other populations in the same distribution areas.This phenomenon indicated that the geographical isolation promoted genetic differentiation and there were convergent evolutions due to the similar micro-habitat. Conclusion] The C. buxifolius in Yunnan shows the higher level of genetic diversity. The inter-specific relationship and distribution of C. buxifolius populations are closely related to geographical location and altitude.