利用ISSR和EST-SSR标记分析茶树遗传多样性的比较

为了比较EST-SSR和ISSR 2种标记在茶树遗传多样性分析上的适用性,应用这2种技术分析了33份茶树资源的遗传多样性.12个ISSR引物共扩增出248条谱带,多态性比率为91.94%,平均多态信息量(PIC)为0.318.30对EST-SSR引物每个位点平均等位基因数为4.9个,平均多态信息量(PIC)为0.499.2种标记都能揭示茶树资源较高的遗传多样性,但从信息量上比较,ISSR标记比EST-SSR标记有较高的分析效率.ISSR和EST-SSR揭示的茶树遗传相似系数分别为0.709和0.734,二者接近.聚类分析表明二者有一定差异,遗传相似系数矩阵相关性分析结果表明2种标记间存在一定的正相关性(r=0.817,P<0.01).因此,这2种标记均可适用于茶树遗传多样性分析.

Analysis of Genetic Diversity of Tea Plants by Using EST-SSR and ISSR Markers

Two different DNA -based techniques, inter -simple sequence repeats (ISSR) and (expressed sequence tags) ESTs-derived SSRs(simple sequence repeats), were used for detecting genetic diversity of 33 accessions of tea germplasm. Using 12 ISSR primers, 248 discernible DNA fragments were generated with 228(91.94%) being polymorphic, and the mean PIC value of each ISSR primer was 0.318. Thirty EST-SSR primers produced an average of 4.9 alleles/locus and an average PIC value of 0.499. Both DNA-based techniques were able to amplify all of the genotypes, showing a high genetic diversity among tea germplasm resources tested. ISSRs and SSRs were compared in terms of their informativeness and efficiency in analysis of genetic diversity and relationships among 33 tea accessions, and ISSRs presented a greater informative content. The mean genetic similarity coefficients among all tea accessions ascribed by ISSR and EST-SSR matrices were close, 0.709 and 0.743, respectively. Some differences in clustering results were observed. The correlation coefficients of similarity were statistically significant for both marker systems used (r=0.817,P < 0.01). It could be inferred that these 2 molecular fingerprinting techniques were both favorable for study of tea genetic diversity.