珍稀植物日本荚蒾遗传多样性的ISSR分析

The genetic diversity assessment of a rare plant Viburnum japonicum by ISSR

日本荚蒾是浙江省重点保护野生植物,种群数量极为稀少,仅零星分布于部分海岛。在野外调查的基础上,对8个居群共125份日本荚蒾样品进行了ISSR遗传多样性分析。从100条ISSR通用引物中筛选出7条引物用于ISSR-PCR,共扩增得到240个谱带,其中多态性谱带232个。在物种水平上,日本荚蒾的多态性位点百分比(PPB)达96.67%,Nei’s基因多样性指数(H)为0.2273,Shannon’s信息指数(I)为0.3581,具有较高的遗传多样性;在居群水平上,日本荚蒾的PPB为32.61%,H为0.0731~0.1363,均值为0.1088;I为0.1092~0.2051,均值为0.1642;居群间基因分化系数(Gst)为0.5271,基因流(Nm)为0.4487,遗传距离为0.0982~0.2540;聚类分析结果表明,同一地理来源的日本荚蒾大多聚为一类,呈一定的地域分布规律。日本荚蒾遗传多样性水平高,但主要存在于居群间,岛屿之间的地理隔离可能是遗传分化的主要原因。

Viburnum japonicum is listed as a key protected wild plant species in Zhejiang province,and it distributes sporadically in a few islands with extremely small populations.In this study,the genetic diversity assessment of V.japonicum was performed by ISSR using 125 plants from eight populations based on field investigation.Seven primers were screened from 100 ISSR universal primers,and a total of 240 bands were amplified,of which 232 were polymorphic.It was found that at the species level,there is a high genetic diversity in V.japonicum with a percentage of polymorphic bands(PPB)of 96.67%,and the Nei's genetic diversity index(H)and Shannon's information index(I)were 0.2273 and 0.3581,respectively.At the population level,its PPB was 32.61%,and H index ranged from 0.0731 to 0.1363 with an average value of 0.1088,while I index varied from 0.1092 to 0.2051 with an average index of 0.1642.The genetic differentiation coefficient(Gst)was estimated as 0.5271,and the gene flow(Nm)was 0.4487.The genetic distances ranged from 0.0982 to 0.2540,and the plant materials of V.japonicum from the same island clustered together to form monophyletic groups,suggesting discrete geographical segregation.The results show a high genetic diversity in V.japonicum,and it manifested between populations,indicating geographical isolation of the islands is the possible cause of genetic differentation.