pYR4 From a Norwegian isolate of Yersinia ruckeri is a putative virulence plasmid encoding both a type IV pilus and a type IV secretion system

Wrobel, A., Ottoni, C., Leo, J.C. ORCID: 0000-0002-7066-7527 and Linke, D., 2018. pYR4 From a Norwegian isolate of Yersinia ruckeri is a putative virulence plasmid encoding both a type IV pilus and a type IV secretion system. Frontiers in Cellular and Infection Microbiology, 8: 373. ISSN 2235-2988

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Enteric redmouth disease caused by the pathogen Yersinia ruckeri is a significant problem for fish farming around the world. Despite its importance, only a few virulence factors of Y. ruckeri have been identified and studied in detail. Here, we report and analyze the complete DNA sequence of pYR4, a plasmid from a highly pathogenic Norwegian Y. ruckeri isolate, sequenced using PacBio SMRT technology. Like the well-known pYV plasmid of human pathogenic Yersiniae, pYR4 is a member of the IncFII family. Thirty-one percent of the pYR4 sequence is unique compared to other Y. ruckeri plasmids. The unique regions contain, among others genes, a large number of mobile genetic elements and two partitioning systems. The G+C content of pYR4 is higher than that of the Y. ruckeri NVH_3758 genome, indicating its relatively recent horizontal acquisition. pYR4, as well as the related plasmid pYR3, comprises operons that encode for type IV pili and for a conjugation system (tra). In contrast to other Yersinia plasmids, pYR4 cannot be cured at elevated temperatures. Our study highlights the power of PacBio sequencing technology for identifying mis-assembled segments of genomic sequences. Comparative analysis of pYR4 and other Y. ruckeri plasmids and genomes, which were sequenced by second and the third generation sequencing technologies, showed errors in second generation sequencing assemblies. Specifically, in the Y. ruckeri 150 and Y. ruckeri ATCC29473 genome assemblies, we mapped the entire pYR3 plasmid sequence. Placing plasmid sequences on the chromosome can result in erroneous biological conclusions. Thus, PacBio sequencing or similar long-read methods should always be preferred for de novo genome sequencing. As the tra operons of pYR3, although misplaced on the chromosome during the genome assembly process, were demonstrated to have an effect on virulence, and type IV pili are virulence factors in many bacteria, we suggest that pYR4 directly contributes to Y. ruckeri virulence.

Item Type: Journal article
Publication Title: Frontiers in Cellular and Infection Microbiology
Creators: Wrobel, A., Ottoni, C., Leo, J.C. and Linke, D.
Publisher: Frontiers Media SA
Date: 30 October 2018
Volume: 8
ISSN: 2235-2988
Rights: Copyright © 2018 Wrobel, Ottoni, Leo and Linke. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Divisions: Schools > School of Science and Technology
Record created by: Jill Tomkinson
Date Added: 17 Jun 2019 15:15
Last Modified: 25 Jun 2019 12:57

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