The Sixth Element: a 102-kb RepABC Plasmid of Xenologous Origin Modulates Chromosomal Gene Expression in Dinoroseobacter shibae

0560767 - MBÚ 2023 RIV GB eng J - Journal Article
Koppenhofer, S. - Tomasch, Jurgen - Ringel, V. - Birmes, L. - Brinkmann, H. - Sproeer, C. - Jarek, M. - Wang, H. - Pradella, S. - Wagner-Doebler, I. - Petersen, J.
The Sixth Element: a 102-kb RepABC Plasmid of Xenologous Origin Modulates Chromosomal Gene Expression in Dinoroseobacter shibae.
mSystems. Roč. 7, č. 4 (2022), č. článku 00264-22. ISSN 2379-5077. E-ISSN 2379-5077
Institutional support: RVO:61388971
Keywords : Roseobacteraceae * plasmid stability * transcriptomics * denitrification * heavy metal resistance * CtrA regulon
OECD category: Microbiology
Impact factor: 6.4, year: 2022
Method of publishing: Open access
https://journals.asm.org/doi/epub/10.1128/msystems.00264-22

The model organism Dinoroseobacter shibae and many other marine Rhodobacterales (Roseobacteraceae, Aiphaproteobacteria) are characterized by a multipartite genome organization. Here, we show that the original isolate (Dshi-6) contained six extrachromosomal replicons (ECRs), whereas the strain deposited at the DSMZ (Dshi-5) lacked a 102-kb plasmid. To determine the role of the sixth plasmid, we investigated the genomic and physiological differences between the two strains. Therefore, both genomes were (re)sequenced, and gene expression, growth, and substrate utilization were examined. For comparison, we included additional plasmid-cured strains in the analysis. In the Dshi-6 population, the conjugative 102-kb RepABC-9 plasmid was present in only about 50% of the cells, irrespective of its experimentally validated stability. In the presence of the sixth plasmid, copy number changes of other ECRs, in particular, a decrease of the 86-kb plasmid, were observed. The most conspicuous finding was the strong influence of plasmids on chromosomal gene expression, especially the repression of the CtrA regulon and the activation of the denitrification gene cluster. Expression is inversely controlled by either the presence of the 102-kb plasmid or the absence of the 86-kb plasmid. We identified regulatory genes on both plasmids, i.e., a sigma 70 factor and a quorum sensing synthase, that might be responsible for these major changes. The tremendous effects that were probably even underestimated challenge the current understanding of the relevance of volatile plasmids not only for the original host but also for new recipients after conjugation.
Permanent Link: https://hdl.handle.net/11104/0333935