基于公共数据库的西瓜EST-SSR信息分析与标记开发

摘要

为了给西瓜遗传基础研究提供新的共显性分子标记,对公共数据中的8619条西瓜EST序列进行处理和分析,获得202个EST-SSR,分布在191条EST序列中,出现频率为2.31%,分布密度为1/19.1kb.其优势重复基序为二核苷酸和三核苷酸(68.8%),在二核苷酸基序中以AG/TG类型为最多(46%);在三核苷酸基序中,以AAG类型为最多(43%).基序重复次数以4次(17.8%)、7次(15.3%)和11次(14.9%)为最多.长度主要分布在20～30 bp(76%).利用上述EST-SSR序列设计获得24对引物在西瓜白化致死近等基因系中进行验证,结果获得了16对有效的扩增引物,占总设计引物对数的66.7%.结果表明:利用公共数据库中的EST序列开发西瓜EST-SSR标记是一种有效的方法.%In order to explore a new co-dominant molecular markers to study the genetic basic research in watermelon. We analysed a total of 8 619 watermelon ESTs from GenBank and sought out 202 SSR contained in 191 EST sequences. The frequency of the SSRs was 2.31％ and mean the distribution density was 1/19. 1 kb in watermelon. The dominant repeat motifs were dinucleotide and trinucleotide. AG/TG was the most repeat type in dinucleotide(46％ ) and AAG was the most repeat type in trinucleotide(43％). The most motif repeat times were 4 (17.8％) ,7 ( 15.3％ ) and 11 ( 14.9％). The length was mainly distributed between 20 to 30 bp. We obtained 24 primer pairs from 202 EST-SSRs in watermelon. Then utilized albino lethal near-isogenic lines of watermelon for verify these primers. We obtained 16 effeetire amplified primer pairs,accouting for 66.7％ of the total number of designed primer pairs. The results suggest that use of public EST databases to develop EST-SSR primers of watermelon are effective method.