Complete genome sequence and evolution analysis of Psychrobacter sp. YP14 from Gammaridea Gastrointestinal Microbiota of Yap Trench

Abstract Psychrobacter sp. YP14, a moderately psychrophilic bacterium belonging to the class Gammaproteobacteria, was isolated from Gammaridea Gastrointestinal Microbiota of Yap Trench. The strain has one circular chromosome of 2,895,311 bp with a 44.66% GC content, consisting of 2333 protein-coding genes, 53 tRNA genes and 9 rRNA genes. Four plasmids were completely assembled and their sizes were 13,712 bp, 19711 bp, 36270 bp, 8194 bp, respectively. In particular, a putative open reading frame (ORF) for dienelactone hydrolase (DLH) related to degradation of chlorinated aromatic hydrocarbons. To get an better understanding of the evolution of Psychrobacter sp. YP14 in this genus, six Psychrobacter strains (G, PRwf-1, DAB_AL43B, AntiMn-1,P11G5, P2G3), with publicly available complete genome, were selected and comparative genomics analysis were performed among them. The closest phylogenetic relationship was identified between strains G and K5 based on 16s gene and ANI (average nucleotide identity) values. Analysis of the pan-genome structure found that YP14 has fewer COG clusters associated with transposons and prophage which indicates fewer sequence rearrangements compared with PRwf-1. Besides, stress response-related genes of strain YP14 demonstrates that it has less strategies to cope with extreme environment, which is consistent with its intestinal habitat. The difference of metabolism and strategies coped with stress response of YP14 are more conducive to the study of microbial survival and metabolic mechanisms in deep sea environment.