基于SSR标记探讨三种金花茶植物的遗传多样性和遗传结构

薄叶金花茶、小花金花茶和小瓣金花茶是三种濒危金花茶植物,为了解珍稀濒危植物遗传多样性和遗传结构,该研究利用微卫星标记对他们的7个种群共184个个体进行了遗传多样性和遗传结构分析。结果表明:11个位点共检测到等位基因92个。在物种水平上,小瓣金花茶平均等位基因数(N_A)为3.9、有效等位基因数(N_E)为2.328、观测杂合度(H_o)为0.520、期望杂合度(H_e)为0.501,高于薄叶金花茶和小花金花茶。在种群水平上,有效等位基因数(N_E)在1.788～2.466之间,期望杂合度(H_e)在0.379～0.543之间;种群间遗传分化系数(FST)在0.143 7～0.453 3之间,种群间基因流(N_m)在0.301 5～1.488 9之间。AMOVA分子变异分析显示65.72%的变异存在于种群内。三种金花茶具有较低水平的遗传多样性和高水平的种群间遗传分化。STRUCTURE和PCoA种群遗传结构分析结果将取样种群分为2组,即薄叶金花茶和小花金花茶大部分个体分为一组,小瓣金花茶大部分个体分为一组。现存所有种群应根据实际情况尽快采取就地保护或迁地保护措施。

Genetic diversity and structure of three yellow Camellia species based on SSR markers

Camellia chrysanthoides, C. micrantha and C. parvipetala are three endangered Camellia species. In order to understand genetic diversity and genetic structure of endangered species, SSR marker was used to evaluate genetic diversity and genetic structure of 184 individuals from seven populations of these three endangered Camellia species. We obtained 92 alleles from eleven microsatellite markers. On the level of species, the mean number of alleles(3.9), the effective number of alleles(2.328), observed heterozygosity(0.520)and expected heterozygosity(0.501)of C. parvipetala were higher than C. chrysanthoides and C. micrantha. On the population level, the effective number of alleles ranged from 1.788 to 2.466 and the expected heterozygosity ranged from 0.379 to 0.543. The F_ST values between each pair of populations ranged from 0.143 7 to 0.453 3, the Nm values ranged from 0.301 5 to 1.488 9. AMOVA suggested that the variation was 65.72% within populations. Low level of genetic diversity and high levels of genetic differentiation were detected for these three Camellia species. The STRUCTURE and PCoA analysis showed that seven populations were clustered into two groups. One group comprised five populations from C. chrysanthoides and C. micrantha, and the other consisted of two populations from C. parvipetala. In situ and ex situ actions should be urgently implemented as soon as possible.