油茶栽培品种SSR指纹图谱构建及聚类分析

Establishment of DNA Fingerprints and Cluster Analysis for Oil Camellia Cultivars Based on SSR Markers

本研究首次利用从油茶DNA序列中开发的SSR标记及其近缘种通用性的SSR标记开展油茶栽培品种的分子甄别研究。7对通用性高、多态性好、扩增清晰的SSR标记构建了油茶43个栽培品种的DNA指纹图谱。遗传参数统计显示,43个油茶品种遗传多样性指数为0.347 1,Shannon指数为0.517 2;7对SSR引物扩增共得到位点36个,其中多态性位点35个,位点多态性达97.22%,其中利用4个标记CO_g SSR16、CO_gssr37、CO_e SSR4和CO_e SSR44两两组合可以完全鉴别出43个油茶栽培品种。聚类结果表明油茶品种的亲缘关系与地理来源存在一定的相关性,如来自江西的赣无系列品种大多能够成组聚类,而来自广西的品种(桂软11号,桂软24号,岑软2号,陆川大果)与来自越南的品种(和江2号,越南油茶,东孝2号)聚在一个类群;但也有一些品种地理来源不同而同样聚在同一类群,显示了油茶遗传背景的多样性与复杂性。本研究为油茶品种鉴定及遗传学研究等提供技术基础及理论依据。

In this study, SSR markers which developed from DNA sequence of Camellia oleifera and its commonality markers from close species were first used in molecular screening of oil camellia cultivars. 7 SSR markers with high polymorphism, good commonality and clear amplification were used to construct the fingerprints for 43 oil camellia cultivars. The genetic diversity index was 0.347 1 and Shannon index was 0.517 2for the 43 cultivars, 36 loci were identified with 7 SSR markers, out of which 35 loci were polymorphic and the percentage of polymorphic bands were 97.22%. In addition, 43 camellia cultivars could be completely identified by using two combinations of primers Co_g SSR16, Co_gssr37, Co_e SSR4 and Co_e SSR44 for their high PIC value. Clustering results showed that there was a certain correlation for the varieties between the genetic relationship and their geographical source, for example, the varieties which from Jiangxi Ganwu series were mostly gathered in the same group, and the varieties from Guangxi province（Guiruan 11, Guiruan 24, Cenruan 2,Luchuandaguo） were gathered in the same group with the varieties from Vietnam（Hejiang 2, Camellia vietnamensis,Donxiao 2）. Some varieties which geographical source inconsistent were also gathered together in the same groups, which showed the diversity and complexity of genetic background for oil camellia. This research could provide reliable evidence and theoretical basis for variety identification and genetic basis of oil camellia.