2株枯草芽孢杆菌全基因组重测序分析

目的: 研究枯草芽孢杆菌的野生菌株(environmental strain)和驯化菌株(domesticated strain)基因组差异,为后续研究枯草芽孢杆菌分泌抗菌相关物质能力提供数据支持。方法: 对2株枯草芽孢杆菌野生菌株Km及CMCC63528进行全基因组测序,并与实验室驯化菌株B.subtilis 168进行序列比较。利用进化树分析菌株的关系;利用皮尔逊相关系数分析菌株间蛋白基因的序列变化关系;用错义突变和同义突变频率计算转化相关基因的序列变化。结果: 2株野生菌株与B.subtilis 168相比各有20000多个单核苷酸多态性位点(single nvcleotide polymorphism,SNP),其中9217个SNP是2株野生菌共有的。进化分析发现2株菌属于subtilis亚种,其错义突变基因显著相关,前100个高度变化的错义突变基因有1/3是相同的。2株野生菌中comG operons,comC,comEC和nucA等与转化及分泌相关基因的序列与B.Subtilis 168相比均发生了显著改变。结论: 2株枯草芽孢杆菌野生菌株和驯化菌株之间有明显的序列差异,2株野生菌株之间相对于驯化菌株其序列变异的基因高度相关。野生菌株和驯化菌株间与蛋白分泌及DNA提取相关的基因序列变化明显。该数据为研究和改造枯草芽孢杆菌以提高其生产和分泌抗菌物质的能力提供一定的序列依据。

Objective: To uncover the genetic variation between environmental and laboratory B.subtilis strains. Methods: The whole genome sequences of two environmental B.subtilis isolates,Km and CMCC63528,were sequenced using high throughout method and their genomes were compared with that of laboratory strain 168.Phylogenetic tree was constructed to understand the relationship among 13 B.subtilis strains,pearson correlation coefficient was calculated for the sequence variation of protein genes in two isolated strains;The frequency of sense and missense mutation was calculated to analyze the sequence for transformation related genes. Results: There are more than 20000 single nucleotide polymorphism(SNPs)for each strain when compared to 168.Of these,9217 SNPs in more than 2000 genes were common to the two environmental strains.Phylogenetic tree analysis indicated both of these two strains belong to the subtilis subspecies.The missense changes were significantly correlated between Km and CMCC63528,and one third of the top 100 most significantly altered genes were identical between these two isolates.Transformation-related and secveting-related genes genes,including genes in the comG operons,comC,comEC and nucA,were significantly altered in environmental strains. Conclusion: There are significant sequence differences between the two environmental B.subtilis strains and 168,and the varied genes in the two environmental strains are highly correlated compared to B.subtilis 168.The sequences in genes related to protein secvetion and DNA uptake between environmental and laboratory B.subtilis strains are siynificant changed.This data would contribute to provide molecular basis to study and modify B.subtilis strain to improve the ability of producing and secreting antimicrobial substamces in the future.