利用SSR分子标记研究国内外黍稷地方品种和野生资源的遗传多样性

Genetic Diversity in Broomcorn Millet(Panicum miliaceum L.) from China and Abroad by Using SSR Markers

【目的】从分子水平研究国内外黍稷种质资源的遗传多样性差异,为黍稷种质资源的研究、保护和利用提供依据。【方法】用不同地理来源且性状差异显著的6份黍稷种质资源对来自高通量测序技术开发的黍稷基因组SSR引物进行筛选,从而获得条带清晰,稳定性好的63对SSR黍稷基因组引物,利用这63对SSR多态性引物对来自国内外的192份黍稷地方品种和野生种质进行遗传多样性分析。统计各试材在同一引物中的条带情况,并以此来分析试材的遗传多样性与所在群体间的亲缘关系。【结果】63对SSR引物共检测出161个等位变异位点,平均每个SSR位点2.56个;平均Shannon-Weaver指数(I)为0.6275,平均基因多样度(Nei)为0.3874,平均PIC值为0.4855。10个不同地理来源群体间表现出显著的遗传多样性差异,各群体的有效等位变异变化范围较窄,最小的是南方群体,为1.2407±0.4315;最大的是内蒙古高原群体,为1.8846±0.4892。国内群体Shannon-Weaver指数为内蒙古高原>东北地区>黄土高原>西北地区>南方地区,而国外Shannon-Weaver指数排序依次为前苏联>欧洲>蒙古>印度>美国。从Nei’s基因杂合度分析,观察杂合度(Ho)最小的是印度群体,为0.2372±0.2962,最大的是内蒙古高原群体,为0.3966±0.3250。期望杂合度(He)最小的是美国群体,为0.3114±0.2203;最大的是内蒙古高原群体,为0.4622±0.1862。从国外种、国内栽培种和国内野生种3个大群体来看,野生种质资源有效等位基因数(1.9285±0.5101)、Shannon-Weaver指数(0.6948±0.2852)、Nei基因多样性指数(0.4373±0.1773)远大于国外种和国内栽培种。而对国内外两大群体而言,国内资源的有效等位基因数(1.8145±0.4519)、Shannon-Weaver指数(0.6657±0.2413)和Nei基因多样性指数(0.412±0.1574)均大于国外资源(1.6862±0.4527、0.5897±0.2469、0.3652±0.1655)。UPGMA聚类分析结果显示,10个地理群聚为三大类,内蒙古高原地区、黄土高原地区、东北地区、西北地区、蒙古地区聚为一类,前苏联、美国、印度、欧洲地区聚为一类,南方地区单独聚为一类。其中,来自东北黑龙江齐齐哈尔的泰来小野糜(34号)在截距0.37处被独立分为一支,来自甘肃的野黍子(19号)在截距0.34处被分为独立个体,表明这两个材料与其他材料遗传差异较大。但从整体遗传多样性上来看192份材料国内外群体遗传分化不明显,群体间的亲缘关系较近,且不同群体间材料存在着互相渗透。【结论】内蒙地区、东北地区、黄土高原地区种质资源遗传多样性最丰富,是遗传关系最为复杂的地区,进一步印证了中国是黍稷起源的中心。

【Objective】The objective of this study is to assess the genetic diversity of broomcorn millet accessions which collected from China and abroad.【 Method】Five hundred pairs of SSR primers developed in the authors＇ laboratory by high-throughput sequencing were used to identify polymorphisms in six representatives randomly selected from the total of accessions. A total of 63 primer pairs produced clear and reproducible polymorphic fragments among the six accessions and then were used to analyze the genetic diversity and relationship of 192 broomcorn millet landraces and wild accessions.【Result】A total of 161 alleles were detected with an average of 2.56 alleles per locus, and the mean Shannon-Weaver index（I）, mean Nei and mean PIC were 0.6275, 0.3874 and 0.4855, respectively. The results indicated that there is a significant difference among the 10 populations of broomcorn millet resources in genetic diversity from diverse geographic origins. The variance range of effective alleles number is 1.2407（South region）- 1.8846（Inner Mongolia）. In domestic populations, the rank of Shannon-Weaver index is Inner Mongolia PlateauTohokuLoess PlateauNorthwestsouthern regions, and the rank of foreign populations is the former Soviet UnionEuropeMongoliaIndiaUnited States. The results of Nei＇s genetic heterozygosity analysis showed that the minimum and maximum of observed（Ho） and expected heterozygosity（He） is 0.2372 from India and 0.3966 from Inner Mongolia as well as 0.3114 from the Unite State and 0.4622 from Inner Mongolia Plateau, respectively. The effective number of alleles（1.9285±0.5101）, Shannon-Weaver index（0.6948±0.2852） and Nei gene diversity index（0.4373±0.1773） of the wild germplasm are much higher which in domestic and foreign accessions. For domestic population and alien population, the effective number of alleles（1.8145±0.4519） of domestic resources, Shannon-Weaver index（0.6657±0.2413）, and Nei gene diversity index（0.412± 0.1574） of domestic accessions were higher than that in foreign resources（1.6862±0.4527, 0.5897±0.2469, 0.3652±0.1655）. UPGMA cluster analysis showed that the 10 geographic populations could be clustered into three categories, the accessions from the Inner Mongolia Plateau, the Loess Plateau, northeast, northwest, Mongolia area were clustered as one group, the former Soviet Union, the United States, India, Europe together as one group, and southern region of China clustered as one independent group. The wild millet（34） which is from Qiqihaer is separated from others at 0.37, the wild millet from Gansu（19） was divided into an independent individual at 0.34, indicating that there are significant genetic variances between the two wild accessions and others. In general, genetic division of population is not significant for 192 domestic and foreign accessions, and there have material interpenetration among different groups.【Conclusion】The Inner Mongolian Plateau, northeast area and the Loess Plateau with the most abundant genetic diversity is the most complex area of genetic relationship, which further confirms that China is the origin center of Panicum miliaceum.