粗皮桉种源遗传多样性SSR分析

Analysis on genetic diversity of Eucalyptus pellita based on SSR markers

【目的】分析粗皮桉的亲缘关系及遗传多样性,为其种质资源利用及分子育种提供参考。【方法】以粗皮桉7个种源（种源1-7）75株样品为材料,基于覆盖巨桉全基因组的21个SSR标记,利用SSR位点、种源遗传分化及种源间遗传距离等分析粗皮桉群体遗传多样性。【结果】21对引物共扩增出252个等位基因（平均每个SSR引物扩增出12个）,平均有效等位基因数（Ne）为4.5788,平均期望杂合度（HE）为0.7227,平均基因多样性（H）为0.7179,平均Shannon信息指数（I）为1.7150。7个种源的遗传多样性参数存在差异,其中种源3的遗传多样性参数最高。群体间的基因分化系数（FST）为0.0965,即9.65%的遗传变异存在于种源间,90.35%存在种源内。7个种源的遗传距离变化范围为0.0965-0.3188,平均为0.2061,聚类分析结果表明,当阀值为0.82时,7个种源被分为昆士兰北部种源和巴布亚新几内亚种源两大类;当阀值为0.84时,昆士兰北部的4个种源被进一步分为两大亚类,种源间遗传距离与种源的地理分布密切相关。【结论】粗皮桉7个种源存在较丰富的遗传多样性,适于开展长周期、多世代改良工作。

【Objective】The genetic diversity and relationship of Eucalyptus pellita were analyzed, in order to provide references for germplasm resources utilization and molecular breeding. 【Method】A total of 75 samples were collected from seven E. pellita provenances. Then the SSR loci, genetic differentiation and genetic distance between provenances of these samples were studied to understand their genetic diversity based on 21 SSR markers of Eucalyptus grandis genome. 【Result】The results showed that, using 21 SSR primers, a total of 252 alleles were amplified from samples（with an average of 12 alleles per SSR primer）, the average number of effective alleles（Ne） was 4.5788, the average expected heterozygosity（ HE） was 0.7227, the average gene diversity（H） was 0.7179, and the average Shannon ＇s information index（I） was1.7150. Furthermore, there existed differences in genetic diversity parameters between 7 provenances, and the provenance 3had the highest genetic diversity parameter. The average coefficient of genetic differentiation between populations（FST） was0.0965, it indicated that there occurred 9.65% genetic variation among provenances and 90.35% within provenance. Moreover, the genetic distances varied from 0.0965 to 0.3188, with an average of 0.2061. The cluster analysis showed that when genetic identity threshold was 0.82, the seven provenances could be clustered into two branches, four north Queensland provenances belonged to branch 1 and three Papua New Guinea provenances belonged to branch 2; when genetic identity threshold was 0.84, the four north Queensland provenances were clustered into two subbranches, it suggested that the genetic distances between provenances closely related to geographical distribution of provenances. 【Conclusion 】The seven provenances of E. pellita have high genetic diversity, which are suitable for long-term research of multi-generational improvement.