Light-Induced Proteomic Changes in Pseudomonas aeruginosa Biofilms

Area of Science:

• Microbiology
• Proteomics
• Bacterial Adaptation

Background:

• Pseudomonas aeruginosa exhibits significant adaptability to environmental stimuli, including light.
• The impact of light on P. aeruginosa biofilm proteomes is not fully understood.
• Bacteriophytochromes are photoreceptors involved in light sensing in bacteria.

Purpose of the Study:

• To investigate the proteomic responses of P. aeruginosa biofilms to white and red light.
• To determine the role of bacteriophytochrome BphP in light-mediated adaptation.
• To identify specific proteins and pathways affected by light exposure.

Main Methods:

• Quantitative proteomics using Orbitrap Exploris 240 mass spectrometry.
• Analysis of P. aeruginosa PA14 wild-type and ΔbphP mutant biofilms under dark, white, and red light.
• Statistical analysis of protein expression data (fold change, FDR).

Main Results:

• Over 3,800 proteins were identified and quantified in P. aeruginosa biofilms.
• 862 proteins showed differential expression in response to light.
• Red light upregulated osmotic stress and carbohydrate metabolism proteins in wild-type, with reversed patterns in ΔbphP mutants.
• Catalase KatE and KatA showed differential regulation, indicating a complex oxidative stress response.
• Virulence factors LasB and LasA expression decreased under light.
• BphP-dependent regulation was observed for AlgB/RpoN network targets like MucA.

Conclusions:

• Bacteriophytochrome BphP is a key regulator of light-mediated proteomic adaptation in P. aeruginosa biofilms.
• Light influences diverse cellular processes including stress response, metabolism, and virulence.
• P. aeruginosa exhibits distinct proteomic profiles in response to different light wavelengths.