菠萝EST资源的SSR信息分析与开发

摘要

表达序列标签-简单重复序列(EST-SSRs)存在于表达序列标签中,是一种最常用的新型微卫星标记.它可以被嵌入到功能基因序列中,有效并高效地提供更多的相关信息.通过对已公开的5659条菠萝Ananas comosus的表达序列标签(ESTs)进行电子筛选,获得了617条含有简单重复序列(SSR)的菠萝EST.平均7.39 kb EST序列中含有1个SSR,其中二核苷酸,三核苷酸和六核苷酸是SSR的主要重复类型,分别占SSR总数的42.61%,29.25%和20.13%.所有重复类型中重复次数最少的是四核苷酸序列(3.46%).AG/TC是二核苷酸中的优势单元.根据搜索出的EST序列,共设计出30对物,其中27对引物扩增产物具有多态性.本次实验中开发的EST-SSR标记是迄今为止有关于菠萝的第1次大规模SSR标记开发.研究结果为利用EST-SSR分子标记进行菠萝连锁图谱构建,数量基因定位,种质资源遗传多样性,亲缘关系研究和指纹图谱构建奠定了基础.%Expressed sequence tags (ESTs) are used for microsatellite development. EST derived from simple sequence repeats (EST-SSRs), one of the most common new microsatellite markers, are more likely to be em-bedded in functional gene sequences, to be less costly and time effective, and may provide more information. In the present study, analysis of 5659 publicly available expressed sequence tags of pineapple (Ananas comosus) was conducted with the Webstat online program. Results of 636 (SSRs), identified electronically in 617 ESTs, showed that the average density was one SSR per 7.39 kb of ESTs screened. Dinucleotide (42.61%), trinu-cleotide (29.25%), and hexanucleotide (20.13%) repeats were the dominant types among the obtained motifs. The least frequent was tetranucleotide repeats (3.46%). TC/AG was most abundant in the dinucleotide motif. Of the 30 functional pairs, 27 primer pairs showed polymorphisms by polymerase chain reaction (PCR) ampli-fications. Thus, the EST-SSRs developed here with the first large-scale development of SSR markers in pineap-ple have the potential to be used for development of genetic and physical maps, quantitative trait loci mapping, genetic diversity studies, association mapping, and finger printing cultivars.