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PltR expression modulated by the global regulators GacA, RsmA, LasI and RhlI in Pseudomonas sp. M18

Xianqing Huang1, Xuehong Zhang, Yuquan Xu

  • 1Key Laboratory of Microbial Metabolism, Ministry of Education, College of Life Sciences and Biotechnology, Shanghai Jiao tong University, 800 Dongchuan Road, Shanghai 200240, PR China.

Research in Microbiology
|February 6, 2008
PubMed

Insights

Pseudomonas sp. M18 produces antibiotics to suppress fungi. PltR, a key regulator, is modulated by Gac/Rsm and quorum-sensing pathways, influencing antibiotic biosynthesis.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Plant Pathology

Background:

  • Pseudomonas sp. M18 produces pyoluteorin (Plt) and phenazine-1-carboxylic acid (PCA) to suppress soil-borne phytopathogenic fungi.
  • PltR, an LysR-type transcriptional activator, is crucial for regulating Plt biosynthesis genes.

Purpose of the Study:

  • To investigate the regulatory mechanisms controlling Plt biosynthesis in Pseudomonas sp. M18.
  • To elucidate the roles of global regulators, including quorum-sensing systems, in modulating pltR expression and Plt production.

Main Methods:

  • Gene expression analysis (transcription and translation) in wild-type and mutant strains of Pseudomonas sp. M18.
  • Construction and characterization of mutants for key regulatory genes (gacA, rsmA, lasI, rhlI, vqsR).

Main Results:

  • PltR expression is negatively regulated by quorum-sensing (QS) genes lasI and positively by vqsR.
  • The Gac/Rsm pathway significantly impacts pltR translation, with inhibition in gacA mutants and enhancement in rsmA mutants.
  • QS genes lasI and rhlI positively influence pltR transcription, indicating their role in regulating Plt biosynthesis.

Conclusions:

  • PltR acts as a mediator in the Gac/Rsm and Las/Rhl regulatory pathways governing Plt biosynthesis.
  • Understanding these regulatory networks provides insights into microbial secondary metabolite production and biocontrol strategies.

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