whole-genome sequencing and biological characteristics analysis of a sheep-derived capsular type A Pasteurella multocida strain

Abstract:

[Background] The Gram-negative Pasteurella multocida (Pm) causes respiratory diseases and septicemia in animal and human. Capsular type A Pm HN02 has been isolated and identified by our laboratory. [Objective] We sequenced the whole genome of HN02 and analyzed the bioinformation, thereby supplementing the genome information of Pm. Through identification and phylogenetic analysis, the virulence genes and genetic evolution of the strain were clarified, respectively, which laid a theoretical basis for clinical prevention and diagnosis of related diseases. [Methods] The whole genome of HN02 was sequenced by SMRT and corrected by Illumina sequencing, followed by genome annotation and bioinformatics analysis. The virulence genes were identified by PCR and the phylogenetic tree was constructed for analysis. [Results] The whole genome of HN02 was 2 333 292 bp, with GC content of 40.15mol%. It was predicted to have 2 389 coding genes, including 19 rRNA genes (6 23S rRNA, 6 16S rRNA, and 7 5S rRNA genes), 62 tRNA genes, and 5 sRNA genes, 84 tandem repeats, 66 minisatellite DNAs, 2 microsatellite DNAs, 9 genomic islands, and 9 prophages. A total of 1 648, 2 190, and 1 917 genes were annotated in Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Cluster of Orthologous Groups of proteins (COG), respectively. Most of them were involved in the metabolic process of Pm. In addition, 85 type III secretion system effector genes, 191 phenotypic mutation genes, 165 virulence factor-related genes, and 1 important secondary metabolism gene cluster were identified. According to the analysis result, a circular map for the genome was plotted, and the genome information was submitted to NCBI to obtain the accession number cp037865. PCR identification showed that the strain had 14 virulence genes such as fimA and toxA and deleted virulence genes such as tadD. Phylogenetic analysis suggested that HN02 had the closest genetic relationship with the strain (MH150895.1) from Beijing. [Conclusion] the whole-genome sequence and biological characteristics of capsular type A Pm HN02 were elucidated and the evolutionary relationship was revealed, providing a reference for preventing the epidemic of Pm-induced disease and exploring the underlying pathogenic mechanism.

Key words:capsular type A Pasteurella multocida;genome sequencing;bioinformatics analysis;virulence-associated genes;phylogenetic analysis