The acylase PvdQ has a conserved function among fluorescent Pseudomonas spp

Area of Science:

• Microbiology
• Biochemistry
• Bacterial Genetics

Background:

• Pyoverdine is a key siderophore for iron uptake in fluorescent Pseudomonas species.
• The enzyme PvdQ is essential for pyoverdine maturation and can degrade N-acyl homoserine lactones (AHLs), which are bacterial quorum-sensing molecules.
• The genomic organization of the pvdQ gene varies among Pseudomonas species, being part of the pyoverdine cluster in some but not others.

Purpose of the Study:

• To compare the enzymatic activities of PvdQ orthologues from different Pseudomonas species.
• To investigate the conserved and unique functions of PvdQ in pyoverdine biosynthesis and quorum-sensing signal degradation.
• To determine the regulatory mechanisms controlling pvdQ gene expression.

Main Methods:

• Comparative analysis of PvdQ orthologues from Pseudomonas fluorescens PfO-1, P. putida KT2440, and P. aeruginosa PA14.
• Enzyme activity assays to assess substrate specificity for AHLs.
• Gene expression studies to examine regulation by iron availability.

Main Results:

• PvdQ orthologues from P. fluorescens, P. putida, and P. aeruginosa exhibit conserved functions in pyoverdine production.
• All tested PvdQ orthologues demonstrate conserved substrate specificity for AHLs.
• Expression of pvdQ orthologues is consistently regulated by iron availability across different species.
• The ability of PvdQ to control quorum-sensing signals appears to be a unique trait of P. aeruginosa.

Conclusions:

• The role of PvdQ in pyoverdine biosynthesis is conserved across various Pseudomonas species.
• PvdQ possesses conserved enzymatic activity towards AHLs, suggesting a broader functional role beyond pyoverdine maturation.
• Iron availability is a conserved regulatory factor for pvdQ gene expression.
• The regulation of quorum-sensing by PvdQ is a specialized function likely unique to P. aeruginosa.