西藏石榴野生群体的SSR遗传多样性分析

【目的】调查西藏地区野生石榴种质资源,分析西藏野生石榴群体的遗传多样性和遗传结构,为野生石榴资源的保护和利用提供理论依据。【方法】使用13对SSR引物对3个自然群体共42份西藏地区野生石榴种质资源材料DNA进行PCR扩增,毛细管电泳检测扩增片段长度,使用GenAlEx和Arlequin等软件对SSR数据进行分析。【结果】13对引物共检测到44个等位基因,平均3.385个,引物的平均有效等位基因数(N_e)、香农信息指数(I)、期望杂合度(H_e)和多态信息量(PIC)分别为1.971、0.771、0.481和0.393。3个野生群体的平均有效等位基因数(N_e)、平均香农信息指数(I)和平均期望杂合度(H_e)分别为1.867、0.646和0.421,林芝b(LZb)群体的遗传多样性水平高于其他2个群体。AMOVA分析表明,群体内遗传变异高达88.43%,3个群体间的遗传分化系数(F_st)为0.116。种质聚类分析将供试种质划分为3个亚群,结果与种质地理来源具有一定关联性。遗传结构分析显示西藏野生石榴有4个可能的基因库来源。【结论】13对SSR引物可用于西藏野生石榴种质的遗传多样性等研究。西藏野生石榴种质的遗传变异主要存在于群体内;林芝b(LZb)群体遗传多样性最高,遗传结构复杂,且含有最多的野生种质采样点,可予以优先保护。

Genetic diversity among wild populations of pomegranate in Tibet by SSR analyses

【Objective】Wild pomegranate (Punica granatum) accessions were found in Tibet. To facilitate the conservation and use of wild pomegranate germplasm, the genetic diversity and population structure of three wild pomegranate populations from Tibet were studied.【Method】Primers for 13 SSR loci were used for PCR amplification of 42 wild individuals from from populations, and the amplified fragment length was determined using capillary electrophoresis. SSR data were analyzed using GenAlEx and Arlequin softwares.【Result】A total of 44 alleles were detected using 13 pairs of primers with an average of 3.835 alleles per locus. The mean values for the effective number of alleles (N_e), Shannon’s Information Index (I), expected heterozygosity (H_e) and the polymorphism information content (PIC) per locus were 1.971, 0.771, 0.481 and 0.393, respectively. The mean N_e, I and H_e of three wild populations were 1.867, 0.646 and 0.421, respectively. In the three populations of wild pomegranate accessions, the genetic diversity of the LZb population was higher than that of the CD and LZa populations. The AMOVA results showed that the percentage of genetic variation within populations was 88.43%, whereas the variance among populations was 11.57%. The F_st among the three wild populations was 0.116. Cluster analysis grouped the 42 accessions into three distinct clusters. Cluster analysis was found to be correlated with geographic origin. The most appropriate number of subpopulations was found to be K=4 using structure analysis.【Conclusion】A total of 13 SSR primers were found to be suitable for genetic diversity analysis of wild pomegranate accessions in Tibet. The genetic variance of wild pomegranate accessions in Tibet was mainly within populations. With having the highest genetic diversity and rich sampling sites, the LZb population merits should be a conservation priority.