拟轮枝镰孢菌EST-SSR信息分析与标记开发
EST-SSR information analysis and marker development for genetic diversity analysis of Fusarium verticillioides

为开发可用于拟轮枝镰孢菌Fusarium verticillioides及其近缘种遗传多样性分析的SSR引物，利用生物信息学方法和PCR技术，通过对从NCBI下载的87 086条拟轮枝镰孢菌的EST序列信息进行分析，设计EST-SSR引物，检测其在拟轮枝镰孢菌及其近缘种中的扩增情况，并用筛选出的多态性引物对15株拟轮枝镰孢菌进行SSR遗传多样性分析。结果表明，在EST序列中，共查找到11 952个SSR位点，592种重复基元，SSR出现频率为1.09%，重复基元出现数量最多的为三核苷酸（54.00%），其中（CAA/TTG） n基元出现频率最高。设计的25对EST-SSR引物在拟轮枝镰孢菌种内的有效扩增率和多态率分别为80.00%与32.00%，对5种近缘镰孢菌种的通用率和多态率分别为40.00%和8.00%。遗传多样性分析结果表明，在相似系数为0.664水平下，供试菌株可划分为4个SSR类群，但类群的划分与菌株的地理来源关；不同菌株间存在明显的遗传分化。表明基于拟轮枝镰孢菌EST序列开发的SSR引物可用于拟轮枝镰孢菌及其近缘种的遗传多样性分析。
To develop EST-SSR markers for genetic diversity analysis of Fusarium verticillioides and related Fusarium spp. strains, the SSRs of Fusarium verticillioides were analyzed and EST-SSR primers were designed based on 87 086 ESTs obtained from NCBI database using bioinformatics method and PCR technology. The genetic diversity of 15 F. verticillioides strains were analyzed with the polymorphic primers screened. The results showed that a total of 11 952 SSRs loci were detected with a frequency of 1.09%, and 592 types of motifs were identified in F. verticillioides ESTs. The most abundant motif was trimucleotide repeats (54.00%). (CAA/TTG)n occurred more often than other repeat motifs. The effective amplification rate of the 25 designed primers in F. verticillioides strains was 80.00%, and 32.00% of these primers were polymorphic. The rates of amplification transferability and polymorphism in five Fusarium spp. strains were 40.00% and 8.00%, respectively. The genetic diversity results indicated that all the strains were clustered into four groups with a similarity coefficient of 0.664, and there was no correlation between SSR grouping and the geographic origins of strains. Obvious genetic diversity existed among the strains. The results indicated that the EST-SSR markers could be used to analyze the genetic diversity of F. verticillioides and related species in Fusarium.