Proteomic analysis of quorum sensing in Rhizobium leguminosarum biovar viciae UPM791

Abstract

Production of quorum-sensing signal molecules of the acyl-homoserine lactone (AHL) type by Rhizobium leguminosarum bv. viciae UPM791 is dependent on its plasmid content. Curing of two of its four native plasmids, pUPM791d and pSym, resulted in loss of production of the largest (C(14)) and the three smaller (C(6)-C(8)) AHLs, respectively. Introduction of a lactonase-containing plasmid resulted in AHL signal degradation and quorum quenching. The quorum-dependent proteome was studied in these strains by DIGE. Quorum quenching affected a small (1.7%) fraction of the detected spots in the wild-type and a smaller (0.6%) fraction in the pSym-cured strain. Unexpectedly, quorum quenching affected up to 3.3% of the detected spots in the pUPM791d-cured strain, suggesting that C(14)-AHL normally interferes with the quorum response mediated by other AHLs. This, together with the observation that ca. 50% of the quorum-regulated proteins in strain UPM791 showed AHL-mediated repression, suggests that an important part of their functionality can be exerted through repression, although AHLs are usually considered as gene expression inducers. The three main quorum-induced polypeptides were identified by MALDI-MS as charge isoforms of the rhizospheric RhiA protein. Another major quorum-induced polypeptide was only present in the pUPM791d-cured strain and could not be identified.

Insights into the Quorum Sensing Regulon of the Acidophilic Acidithiobacillus ferrooxidans Revealed by Transcriptomic in the Presence of an Acyl Homoserine Lactone Superagonist Analog

“…In Gram-negative bacteria, the main characterized QS system involves three key molecular elements ( Venturi and Subramoni, 2009 ): (i) N-acyl homoserine lactones (AHLs), which act as autoinducers (AIs); (ii) the AHLs synthase encoded by a luxI -like gene; (iii) a transcriptional regulator, which is encoded by a luxR -like gene and which binds AHL molecules and modulates the expression of different target genes that constitute the QS regulon. Depending on the bacterial species and also on the experimental strategies (transcriptomic or proteomic), the size of the QS regulons oscillates between 3 and 8% of the identified ORFs ( Vasil, 2003 ; Wagner et al, 2003 ; Cantero et al, 2006 ; Qin et al, 2007 ; Stevens et al, 2011 ; Majerczyk et al, 2014 ).…”

Cell–Cell Communication in Azospirillum and Related PGPR

“…These global omics approaches revealed that QS can affect several percent of the protein or gene content in bacteria, as observed for B. phymatum or Rhizobium leguminosarum (Coutinho et al 2013 ;Cantero et al 2006 ).…”

Mining quorum sensing regulated proteins – Role of bacterial cell‐to‐cell communication in global gene regulation as assessed by proteomics

“…Recently, Cantero et al 42 performed a comparative proteome analysis to identify QS‐regulated proteins of R. leguminosarum bv. viciae UMP791, a typical pea‐nodulating strain harboring four plasmids coding for different AHL synthases and genes involved in symbiotic functions.…”