Pseudomonas aeruginosa strains belonging to phylogroup 3 frequently exhibit an atypical quorum sensing response: the case of MAZ105, a tomato rhizosphere isolate.
Sara E Quiroz-Morales, Luis Felipe Muriel-Millán, Gabriel Y Ponce-Soto, Abigail González-Valdez, Israel Castillo-Juárez, Luis Servín-González, Gloria Soberón-Chávez
{"title":"<i>Pseudomonas aeruginosa</i> strains belonging to phylogroup 3 frequently exhibit an atypical quorum sensing response: the case of MAZ105, a tomato rhizosphere isolate.","authors":"Sara E Quiroz-Morales, Luis Felipe Muriel-Millán, Gabriel Y Ponce-Soto, Abigail González-Valdez, Israel Castillo-Juárez, Luis Servín-González, Gloria Soberón-Chávez","doi":"10.1099/mic.0.001401","DOIUrl":null,"url":null,"abstract":"<p><p><i>Pseudomonas aeruginosa</i> is a widespread γ-proteobacterium and an important opportunistic pathogen. The genetically diverse <i>P. aeruginosa</i> phylogroup 3 strains are characterized by producing the pore-forming ExlA toxin and by their lack of a type III secretion system. However, like all strains of this species, they produce several virulence-associated traits, such as elastase, rhamnolipids and pyocyanin, which are regulated by quorum sensing (QS). The <i>P. aeruginosa</i> QS response comprises three systems (Las, Rhl and Pqs, respectively) that hierarchically regulate these virulence factors. The Pqs QS system is composed of the PqsR transcriptional factor, which, coupled with the alkyl-quinolones HHQ or PQS, activates the transcription of the <i>pqsABCDE</i> operon. The products of the first four genes of this operon produce HHQ, which is then converted to PQS by PqsH, while PqsE forms a complex with RhlR and stabilizes it. In this study we report that mutations affecting the Pqs system are particularly common in phylogroup 3 strains. To better understand QS in phylogroup 3 strains we studied strain MAZ105 isolated from tomato rhizosphere and showed that it contains mutations in the central QS transcriptional regulator, LasR, and in the gene encoding the PqsA enzyme involved in the synthesis of PQS. However, it can still produce QS-regulated virulence factors and is virulent in <i>Galleria mellonella</i> and mildly pathogenic in the mouse abscess/necrosis model; our results show that this may be due to the expression of <i>pqsE</i> from a different PqsR-independent promoter than the <i>pqsA</i> promoter. Our results indicate that using anti-virulence therapy based on targeting the PQS system will not be effective against infections by <i>P. aeruginosa</i> phylogroup 3 strains.</p>","PeriodicalId":49819,"journal":{"name":"Microbiology-Sgm","volume":"169 10","pages":""},"PeriodicalIF":2.6000,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10634362/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Microbiology-Sgm","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1099/mic.0.001401","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MICROBIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Pseudomonas aeruginosa is a widespread γ-proteobacterium and an important opportunistic pathogen. The genetically diverse P. aeruginosa phylogroup 3 strains are characterized by producing the pore-forming ExlA toxin and by their lack of a type III secretion system. However, like all strains of this species, they produce several virulence-associated traits, such as elastase, rhamnolipids and pyocyanin, which are regulated by quorum sensing (QS). The P. aeruginosa QS response comprises three systems (Las, Rhl and Pqs, respectively) that hierarchically regulate these virulence factors. The Pqs QS system is composed of the PqsR transcriptional factor, which, coupled with the alkyl-quinolones HHQ or PQS, activates the transcription of the pqsABCDE operon. The products of the first four genes of this operon produce HHQ, which is then converted to PQS by PqsH, while PqsE forms a complex with RhlR and stabilizes it. In this study we report that mutations affecting the Pqs system are particularly common in phylogroup 3 strains. To better understand QS in phylogroup 3 strains we studied strain MAZ105 isolated from tomato rhizosphere and showed that it contains mutations in the central QS transcriptional regulator, LasR, and in the gene encoding the PqsA enzyme involved in the synthesis of PQS. However, it can still produce QS-regulated virulence factors and is virulent in Galleria mellonella and mildly pathogenic in the mouse abscess/necrosis model; our results show that this may be due to the expression of pqsE from a different PqsR-independent promoter than the pqsA promoter. Our results indicate that using anti-virulence therapy based on targeting the PQS system will not be effective against infections by P. aeruginosa phylogroup 3 strains.
期刊介绍:
We publish high-quality original research on bacteria, fungi, protists, archaea, algae, parasites and other microscopic life forms.
Topics include but are not limited to:
Antimicrobials and antimicrobial resistance
Bacteriology and parasitology
Biochemistry and biophysics
Biofilms and biological systems
Biotechnology and bioremediation
Cell biology and signalling
Chemical biology
Cross-disciplinary work
Ecology and environmental microbiology
Food microbiology
Genetics
Host–microbe interactions
Microbial methods and techniques
Microscopy and imaging
Omics, including genomics, proteomics and metabolomics
Physiology and metabolism
Systems biology and synthetic biology
The microbiome.