基于SSR标记的圆叶桉遗传多样性分析

Genetic analysis of Eucalyptus pulverulenta based on SSR markers

【目的】摸清国内圆叶桉Eucalyptus pulverulenta花卉资源遗传多样性概况,为种质资源利用及分子育种提供参考。【方法】利用多态性高的15个SSR标记,对7个来源的59株圆叶桉进行SSR基因分型和遗传多样性分析。【结果】1)59株圆叶桉在15个SSR标记共检测到83个等位片段数(NA),平均每个标记的等位片段数为5.5个,每个标记的等位片段数2~10个,平均有效等位片段数(NE)2.4个。观测杂合度(HO)和期望杂合度(HE)的平均值为0.401和0.491,多态性信息量(PIC)的平均值为0.455,具有较高的多态性。圆叶桉群体间遗传分化系数(Fst)为0.208,即有20.8%的变异存在于不同群体间;2)个体间遗传距离范围为0.033~0.698,平均为0.377,群体间亲缘关系较近,遗传背景相对单一。圆叶桉群体分为两个亚组,与其天然分布范围一致;3)圆叶桉群体间的遗传一致度为0.533~0.987,来自云南佳艺园艺和云南绿梦花卉的圆叶桉遗传一致度最高,推测二者可能为来源相同的品种。分子方差分析(AMOVA)结果表明个体间变异是方差分量的主要来源。【结论】15个SSR标记遗传多态性较高,可用于圆叶桉的遗传分化研究。个体间的分型结果表明,国内市场上常见的圆叶桉均为有性繁殖的实生苗,不同来源圆叶桉群体间的遗传分化程度较小,遗传变异主要发生在个体间。本研究对圆叶桉进行遗传多样性和遗传结构分析,对种质资源的评价和利用都具有重要意义。

【Objective】In order to find out genetic diversity condition of Eucalyptus pulverulenta resources in China,and to provide reference for germplasm resources utilization and molecular breeding.【Method】15 SSR makers with high polymorphism were used for genotyping and genetic diversity analysis of 59 E.pulverulenta from 7 sources.【Result】1)A total of 83 alleles were detected by 15 SSR markers,averaging 5.5 alleles per marker,the number of alleles per marker ranged from 2 to 10,averaging 2.4 effective alleles per marker.The average value of observed heterozygosity and expected heterozygosity were 0.401 and 0.491,respectively.The general polymorphism was high with an average polymorphic information content of 0.455,indicating these markers were suitability for studying genetic differentiation of E.pulverulenta.The genetic differentiation coefficient between populations(Fst)was 0.208,it indicated that there occurred 20.8%genetic variation among populations;2)The genetic distance varied from 0.033 to 0.698,with an average of 0.377.The results indicated that the genetic background was relatively single and the genetic relationship was close.The cluster analysis showed that 59 samples were clustered into two subgroups,which was consistent with the natural distribution of E.pulverulenta;3)The genetic coefficient of the populations ranged from 0.533 to 0.987.The genetic coefficient of E.pulverulenta from Yunnan Jiayi Horticulture and Yunnan Lümeng Huahui was the highest,which suggested that the two populations might be from the same source.Analysis of molecular variance showed that individual variation is the main source of variance component.【Conclusion】This study used 15 SSR markers,which had high genetic polymorphisms and could be used to study the genetic differentiation of E.pulverulenta.The results of cluster analysis among individuals showed that the common E.pulverulenta in the domestic market are generative reproduced seedlings.The extent of genetic differentiation among different populations were at a low level,and most of variations existed within individuals.The results will be great significance for the germplasm resource evaluation and utilization in E.pulverulenta.