Quorum sensing and DNA methylation play active roles in clinical Burkholderia phase variation

ABSTRACT: Phenotypic diversity in bacteria often results from adaptation to changing environmental conditions and is exemplified by variable colony morphotypes within the Burkholderia. Discrete genomic changes and modulation in gene expression have previously been reported in Burkholderia pseudomallei undergoing adaptation. However, loss of a complete replicon (the pC3 virulence megaplasmid) was observed amongst adapted colony morphotype variants of Burkholderia cepacia complex (Bcc) species, affecting their production of virulence factors. We report that variants arising in Burkholderia ambifaria clinical isolates - with affected phenotypes - have retained pC3, suggesting that an alternative phase variation mechanism could occur in B. ambifaria. Proteomic and phenotypic characterisation showed that morphotype variants of B. ambifaria strains CEP0996 (pC3-null) and HSJ1 (pC3-positive) share similarities in phenotypes controlled by the Cep quorum sensing system. Thus, we determined the role of QS in B. ambifaria HSJ1 phase variation and confirmed that the main QS system Cep is important for the emergence of variants. As DNA methylation is one of the main epigenetic factors studied in bacterial phase variation and regulates some Burkholderia cenocepacia virulence factors, we hypothesized that B. ambifaria HSJ1 phase variation could also be regulated by adenosine DNA methylation. By deleting the three putative adenosine DNA methyltransferases, we showed that an orphan type II DNA methyltransferase prevents the emergence of phase variants. This is the first study to report quorum sensing and adenosine DNA methylation as two antagonist systems independently controlling phase variation.

INSTRUMENT(S): Orbitrap Fusion

ORGANISM(S): Burkholderia Ambifaria Bacteria

SUBMITTER: Matthew Padula  

LAB HEAD: Eric Déziel

PROVIDER: PXD055955 | Pride | 2025-02-10

REPOSITORIES: pride