一株虹鳟源嗜冷黄杆菌CH06的基因组进化及毒力相关基因分析

为了深入揭示我国鱼类病原菌嗜冷黄杆菌的基因组进化及其致病机制,本实验对嗜冷黄杆菌毒力菌株CH06进行全基因组测序,比较基因组分析并挖掘其毒力相关基因.基因组测序结果显示,CH06的基因组大小为2836981 bp,GC含量为32.56％,注释出2437个编码基因.通过平均核苷酸一致性(ANI)分析结果显示,CH06与1...

Genomic evolution and virulence-associated genes of the Flavobacterium psychrophilum CH06 isolated from Oncorhynchus mykiss

Flavobacterium psychrophilum (F. psychrophilum) is an important bacterial pathogen of salmonid fish. In order to understand the genomic evolution and pathogenesis of this fish pathogen in our country, the virulent strain CH06 was subjected to whole genome sequencing and analyzed using comparative genomics, and virulence-associated genes were predicted. The genome sequencing shows that the genome consists of a single circular chromosome of 2 836 981 base pair (bp) harboring 2 437 protein-coding genes with an overall G+C content of 32.56%. The results of ANI analysis show that ANI value between CH06 and 12 F. psychrophilum strains is higher than 99%, indicating CH06 belongs to F. psychrophilum. Analysis of the genome sequences reveals that CH06 consists of 5 insertion sequences, 4 genomic islands and 3 prophage sequences. This result shows that these mobile genetic elements lead to the genome evolution of CH06. Collinear and phylogenetic analysis shows that CH06 is more similar to CSF259-93 from USA and FPG101 from Canada. Secretion system analysis identifies that CH06 genome carries full type I (T1SS) and type IX (T9SS) secretion system. We further examine the 2 437 predicted proteins and identify 27 proteins predicted to be secreted by the T9SS. Furthermore, the genome of CH06 is predicted to encode 10 histidine kinases (HKs) and 15 response regulators (RRs). These results reveal that CH06 has evolved sophisticated mechanisms to export various virulence factors across the bacterial cell envelope, and sense and respond to environmental changes. In this study, the genome evolution and virulence-associated genes of CH06 are analyzed, providing a basis for research on the genomic evolution and diversity and pathogenic mechanism of this fish pathogen in our country.