目的 分析鱼腥草Houttuynia cordata转录组中的SSR位点信息,并设计简单重复序列(SSR)引物,以期为鱼腥草分子标记辅助育种提供有力工具。方法 利用MISA工具筛选了鱼腥草转录组测序获得的63954条unigenes,对其SSR位点信息进行了分析;在此基础上利用Primer 3设计SSR引物,并随机选择50对SSR引物对16株不同来源的鱼腥草进行多态性扩增分析。结果 在鱼腥草的转录组中,共搜索到4800个SSRs,分布于4413条unigenes,SSR位点出现频率为7.51%。SSRs位点中三核苷酸重复是主要类型,占总SSRs的41.54%;其次是单核苷酸重复基序(占27.35%)。SSRs所包含的重复基元中,单核苷酸重复基元A/T是优势重复基元类型,占总SSRs的27.0%。利用Primer3共设计出3068对SSR引物。随机选择50对引物进行PCR扩增,其中43对(86.0%)扩增出清晰、可重复的条带,且表现出多态性。利用UPGMA作图,将16个样品分为2类。结论 鱼腥草转录组中SSR位点出现频率高,类型丰富;大量的SSR为其遗传多样性分析和遗传图谱构建奠定基础。

Objective Simple sequence repeats (SSR) loci information in the transcriptome of Houttuynia cordata was analyzed in this study and the more powerful tools were provided for molecular marker-assisted breeding in this plant. Methods SSR loci were searched in all 63954 unigenes by using MISA. SSR loci information was analyzed and SSR primers were designed by Primer 3. Furthermore, 50 pairs of primers were randomly selected for the polymorphic analysis on 16 H. cordata plants collected from different habitats. Results A total of 4800 SSRs were found in the transcriptome of H. cordata, which distributed in 4413 unigenes with the distribution frequency of 7.51%. Tri-nucleotide repeat was the main type, accounted for as much as 41.54% of all SSRs, followed by mono-nucleotide repeat motif (27.35%). The mononucleotide repeat motifs of A/T were the predominant repeat type (27.0%). A total of 3068 pairs of SSR primers were designed by using Primer 3. For validating the availability of those SSR primers, 50 pairs of primers were randomly selected for PCR amplification. Among them, 43 pairs of primers (86.0%) produced clear and reproductive bands, which showed polymorphism, and 16 H. cordata plants collected from different places were divided into two groups by UPGMA. Conclusion There are numerous SSRs in H. cordata transcriptome with high frequency and various types, this will provide the basis for study on genetic diversity and genetic map for H. cordata.

国家自然科学基金资助项目(30870230);湖南省科技计划项目(2013FJ6090,2014FJ4207);湖南省高校创新平台开放基金项目(15K100);湖南省生物类专业大学生创新训练中心及大学生创新项目资助