甘薯与牵牛EST资源的SSR信息分析

为挖掘番薯（Ipomoea）属EST-SSR资源，从NCBI数据库下载23406条甘薯（Ipomoea batatas (L.) Lam.）EST和62282条牵牛（Ipomoea nil (L.) Roth）EST，利用生物信息学软件预处理、去冗余、拼接处理后得到12812条无冗余的甘薯EST（6.70 Mb）和28422条牵牛唯一序列（17.19 Mb）。对这些序列进行SSR搜索，在甘薯上获得328个SSR位点，发生频率为2.56%；牵牛上筛选到962个SSR位点，出现频率为3.38%。甘薯和牵牛EST-SSR具有多个共同特征：在SSR位点中，主要是二核苷酸重复类型，其次是三核苷酸重复；在二核苷酸重复中，出现最多的重复基序为AG/CT，其次是AT/AT；在三核苷酸重复中，主要基序是AAG/CCT；SSR位点的长度主要集中在20~22 bp。结果表明，这些搜索出的EST-SSR重复基序类型丰富、多态性潜能高，具有较高的开发和利用价值。

Analysis of SSR Information in EST Resource of Ipomoea batatas (L.) Lam.Ipomoea and Ipomoea nil (L.) Roth

To excavate the EST-SSR resourses of Ipomoea, 12812 non-redundant ESTs with the total length about 6.70 Mb were obtained by assembling 23406 ESTs from Ipomoea batatas (L.) Lam.Ipomoea batatas in NCBI. With the same way, 28422 unique sequences covering 17.19 Mb were generated from Ipomoea nil (L.) RothIpomoea nil. A total of 328 SSR loci for Ipomoea batatas with the the frequency of 2.56% and 962 SSR loci for Ipomoea nil with the frequency of 3.38% were identified by MISA. The EST-SSRs from Ipomoea batatas and Ipomoea nil had many common features. Among all the identified SSRs, dinucleotide repeats were dominant motifs and then were trinucleotide repeats. For dinucleotide repeats, AG/CT was the major motif, followed by AT/AT. And AAG/CCT was the most frequent motif among the trinucleotide repeats. The length of EST-SSRs was mainly distributed betweenn 20 bp to 22 bp. The result in the paper indicated that these EST-SSRs with abundant repeat motif types and high potential polymorphism have high value for exploitation and utilization.