草莓EST-SSR标记的开发与应用

Development and utilization of EST-SSR marker in strawberry

从公共数据库中下载61 731条草莓表达序列标签(Expressed Sequence Tag,EST),组装后得到系列非冗余EST 14 948条,总长度为9 969.35 kb,挖掘到1 807个SSR,分布在1 515条序列上,发生频率为10.14%,平均每5.52kb出现1个SSR(Simple Sequence Repeat)。其中,235条系列包含2个或2个以上SSR,76个SSR以复合形式出现。二核苷酸(794个SSR)和三核苷酸(795个SSR)是主要的类型,所占比例分别为43.94%和44.00%。AG/CT(691个)和AAG/CTT(278个)在二、三核苷酸中占主导地位。利用这些序列,设计47对引物,对生产上主栽的3个日本品种进行多态性研究,44对引物有扩增产物,6对表现多态性。结果表明,从草莓相关EST数据库中开发的EST-SSR引物可行且有用,在草莓品种鉴定、种质资源分析、遗传作图等研究方面有广阔的应用前景。

61 731 ESTs（Expressed Sequence Tags） of strawberry were downloaded from public databases,14948 non-redundant ESTs were assembled,the total length of these non-redundant ESTs was 9 969.35 kb.1 807 SSRs（Simple Sequence Repeats） distributed in 1 515 ESTs were mined,the appearance frequency was 10.14%,one average SSR was found per 5.52 kb.235 ESTs contained two or more than two SSRs,compound form was shown in 76 ESTs.Dinucleotides（794 SSR） and trinucleotides（795 SSR） EST-SSRs were dominant,accounted for 43.94%,44.00% respectively.AG/CT and AAG/CTT were major motifs between dinucleotides and trinucleotides.The frequency was 38.24% and 15.38%,respectively.Using these sequences,47 primer pairs were designed and tested in 3 major Japanese cultivars for farmers,44 primer pairs could be amplified,6 primer pairs revealed polymorphisms.The results showed that the primers which developed from EST databases were efficient and practicable and could be used for strawberry cultivar identification,germplasm analysis and linkage mapping.