Comparative analysis of genetic diversity among the tea cultivars from China, Japan and Kenya revealed by ISSR and EST-SSR | ISSR和EST-SSR标记在检测中国、日本和肯尼亚茶树品种遗传多样性上的比较分析

chinois. 本研究利用ISSR和EST-SSR标记对中国13个、日本4个与肯尼亚5个茶树品种的遗传多样性进行分析,重点比较了ISSR和EST-SSR在多态性位点数、引物解析能力、多态性信息含量和标记系数等方面的差异。结果表明在位点检测能力上ISSR明显高于EST-SSR,每条ISSR引物可检测的平均条带数（12.5）比每对EST-SSR引物（3.1）高三倍。ISSR标记的Rp值是EST-SSR标记的6.3倍,其多态性信息含量（PIC）和标记系数（MI）也明显高于EST-SSR,这表明ISSR具较高的多态性位点检测能力和较高的标记效率。EST-SSR揭示的Nei基因多样性（H=0.28）高于ISSR（0.21）,这种差异进而会影响到遗传距离和聚类分析的结果。在检测中国、日本和肯尼亚茶树品种的遗传差异上,两种标记表现出较一致的趋势,中国茶树品种在多态性位点数量、Nei基因多样性、遗传距离上均大于日本和肯尼亚的茶树品种。研究还表明,由于EST-SSR可检测到等位位点的变异,它比ISSR可以更准确地反映和揭示供试品种的遗传多样性水平。同时由于单个EST-SSR标记检测到的位点数量较ISSR标记少,且特异性较强,谱带较易分辨,因此比ISSR标记更适用于对大量样本的分析。[著者文摘]

anglais. The genetic diversity among 22 tea cultivars from China, Kenya and Japan was analyzed by using ISSR and EST-SSR with emphasis on the difference of two kinds of markers. The results showed that average number of polymorphic bands amplified by ISSR reached 12.5 bands per primer pairs, which was three times more than that of generated by EST-SSR, the latter was about 3.1 bands per primer pairs. And that average value of resolving power （Rp） oflSSR marker was up to 6.5 folds against that of EST-SSR. Meanwhile ISSR markers can reveal higher poly morphic information content （PIC） and marker index （MI） than that of EST-SSR. The above data indicated that ISSR should have much strong capability for detecting the polymorphic bands and highly marking efficiency compare to the EST-SSR. However, The EST-SSR demonstrated that the ability for calculating the Nei＇s gene diversity would be better than the ISSR, the former was up to 0.28 in Nei＇s gene diversity while the latter is about 0.21, which might ascribe to be incapable of detecting alleles by ISSR. It would further influence on the estimation of genetic distance and clustering analysis. In this study, ISSR and EST-SSR markers were both proved to be effective to reveal the degree of genetic diversity among tea cultivars originated from China, Kenya and Japan. Genetic parameters such as number ofpolymorphic loci, Nei＇s gene diversity （H） and genetic distance among Chinese tea cultivars were higher than that of the tested tea cultivars from Kenya and Japan based on ISSR and EST-SSR markers. This study also indicated that EST-SSR markers might be more accurate to evaluate genetic diversity than that of ISSR because the former could reveal the variation of alleles on a locus. In addition, EST-SSR markers could be more adaptable for large-scale sample analysis than that of ISSR due to the few and clear EST-SSR bands were easily distinguished and recorded.