检疫性杂草毒莴苣EST-SSR标记的开发及应用
Development and utility of EST-SSR marker in quarantine weed Lactuca serriola

为明确毒莴苣EST序列中SSR的特点,并开发EST-SSR分子标记用于毒莴苣及其近似种的分类鉴定及遗传多样性分析,以筛选的7 438条毒莴苣EST序列为基础,利用SSRIT软件结合人工搜索查找SSR位点,并采用 Primer Premier 5.0软件设计EST-SSR引物,以毒莴苣及其近似种为材料对所合成引物进行多态性检测,应用UPGMA法构建11个毒莴苣及其近似种的系统发育树。结果表明,共搜索到SSR位点1 465个,发现重复基元598种,其中二、三、六核苷酸重复是主要的重复类型。合成的24对引物中有9对表现出多态性,利用这9对EST-SSR引物分析毒莴苣等11份材料的亲缘关系,其相似性系数在0.432~1.000之间;于0.513处可被划分为3大类:Ⅰ类包括翅果菊和北山莴苣,Ⅱ类只有宿根莴苣1种,Ⅲ类包括毒莴苣和莴苣。
In order to reveal the characteristics of SSRs derived from prickly lettuce ESTs and develop EST-SSR molecular markers for genetic diversity study and identification of Lactuca serriola and related species, SSRs of prickly lettuce were analyzed by bioinformatics method based on 7 438 non-redundant ESTs which obtained from NCBI database. The EST-SSR primers were designed on Primer Premier 5.0, and the phylogenetic tree of L. serriola and related species was established by UPGMA. A total of 1 465 SSRs loci were screened and 598 types of motifs were identified in ESTs of prickly lettuce. The dominant motifs types were dinucleotide, trinucleotide and hexanucleotide repeats. Nine polymorphic primer pairs were used to analyze genetic diversity of 11 tested materials. The genetic similarity of paired cultivars varied from 0.432 to 1.000. The 11 materials could be divided into three groups with a similarity coefficient of 0.513. GroupⅠ included two cultivars, Pterocypsela indica and L. sibirica; L. perennis was the only cultivar in groupⅡ, and group Ⅲ included two cultivars, L. serriola and L. sativa.