右旋糖酐生产用菌种肠膜状明串珠菌CMCC(B)34991的全基因组分析

Whole genome sequence analysis of Leuconostoc mesenteroides CMCC(B)34991 strain used for production of dextran

目的对我国右旋糖酐生产用菌种肠膜状明串珠菌CMCC(B)34991的全基因组分子特征进行分析。方法将CMCC(B)34991菌种培养后,依次进行形态观察、生化鉴定、质谱分析及16S rRNA序列测定,同时应用高通量测序技术,对CMCC(B)34991菌种进行全基因组序列测定和比较基因组学分析。结果CMCC(B)34991菌种与4种肠膜状明串珠菌亚种代表株的16S rRNA基因序列相似度均大于99.5%。CMCC(B)34991菌种染色体全基因组序列全长为1857684 bp,平均GC含量为38.2%,共含有2089个基因,编码基因占整个基因组序列的88.4%,其中具有直系同源簇(clusters of orthologous groups,COG)功能1621个,参与KEGG代谢通路1112个。CMCC(B)34991菌种与4种肠膜状明串珠菌亚种代表株之间核苷酸同源性很高,平均核苷酸一致性(average nucleotide identity,ANI)值大于98.5%,DNA-DNA杂交(DDH)值超过89%,它们之间的共有基因1186个,而CMCC(B)34991菌种基因组特有基因247个。进化树显示,肠膜状明串珠菌与其他明串珠菌的分子进化历程不同。结论首次获得了我国右旋糖酐生产用菌种肠膜状明串珠菌CMCC(B)34991全基因组的基本特征,为后续右旋糖酐的生产工艺优化和生产用菌种的质量控制奠定了基础。

Objective To analyze the molecular characteristics of whole genome of Leuconostoc mesenteroides CMCC(B)34991 strains used for production of dextran in China.Methods L.mesenteroides CMCC(B)34991 strain was cultured and subjected to morphological observation,biochemical identification,MALDI-TOF MS and 16S rRNA sequence analysis.High-throughput sequencing technology was used for the analyses of whole genome sequence and comparative genomics of the strain.Results The similarities of 16S rRNA sequence of CMCC(B)34991 strain to those of four representative strains of L.mesenteroides subspecies were more than 99.5%.The whole genome of L.mesenteroides CMCC(B)34991 chromosome was 1857684 bp in length,with an average GC content of 38.2%,which consisted of 2089 genes.The encoding genes accounted for 88.4%of the entire genome sequence,of which 1621 showed the function of clusters of orthologous groups(COG)and 1112 involved in the KEGG metabolic pathway.The nucleotide of CMCC(B)34991 strain was highly homologous to those of four representative strains of L.mesenteroides subspecies,with an average nucleotide identity(ANI)of more than 98.5%and a DNA-DNA hybridization(DDH)value of more than 89%.There were 1186 common genes among the five L.mesenteroides genomes.However,247 unique genes were identified in CMCC(B)34991 genome.Phylogenetic tree showed that the molecular evolution course of L.mesenteroides was different from those of other Leuconostoc strains.Conclusion The basic characteristics of whole genome of L.mesenteroides CMCC(B)34991 strain used for productin of dextran in China was obtained for the first time,which laid a foundation of the subsequent optimization of production process of dextran and quality control of bacterial strains for production.