Prediction and analysis of mobile gene elements in Vibrio fluvialis

  Objective  To evaluate the types and distribution of mobile gene elements (MGEs) in the genome of Vibrio fluvialis and investigate their significance for the adaptive evolution of V. fluvialis.

  Methods  The publicly available genomes of 170 V. fluvialis strains were downloaded from NCBI SRA database, and MGEfinder was used to identify the MGEs in the genomes of V. fluvialis, and the diversity, insertion activity, distribution and virulence genes of MGEs were studied.

  Results  A total of 1 227 MGEs were identified in 170 strains of V. fluvialis, including intact phage, questionable/incomplete phage, insertion element (IS element), group II intron, serine/tyrosine recombinase, containing CDS and TIR, coding gene sequences (CDS) and open reading frame-free sequences (No CDS). Among the 317 unique insertion clusters, 307 had low transposition activity, but the MGEs with high transposition activity were distributed more widely in V. fluvialis. The functions of coding genes carried by MGEs mainly involved gene duplication, duplication, repair, and gene transcription. The distribution of MGEs had no difference between environmental and clinical isolates of V. fluvialis. A variety of virulence factors were identified in four MGEs, including insertion elements, serine/tyrosine recombinase, containing CDS and TIR, and coding gene sequences, and the virulence factors carried by different MGEs were different.

  Conclusion  V. fluvialis possess various types and functions of MGEs and exhibits adaptive evolutionary characteristics dominated by MGEs with high transposition activity.