Fatty acid-mediated signalling between two Pseudomonas species.

Area of Science:

• Microbiology
• Bacterial Communication
• Plant-Microbe Interactions

Background:

• Intercellular signaling is crucial for bacterial behavior and adaptation.
• Pseudomonas species are important in various environments, including plant roots.
• Understanding bacterial communication mechanisms can reveal novel strategies for controlling plant-associated microbes.

Purpose of the Study:

• To identify mediators of intercellular signaling in Pseudomonas putida and between Pseudomonas aeruginosa and P. putida.
• To elucidate the signaling pathway involved in the expression of the ddcA gene.
• To understand the role of fatty acids in bacterial communication and plant root colonization.

Main Methods:

• Identification of signaling molecules in bacterial supernatants and corn root exudates.
• Analysis of gene expression (ddcA) in response to identified signaling molecules.
• Investigation of the two-component regulatory system (RoxS/RoxR) and quorum sensing systems (LasI/LasR, RhlI/RhlR).

Main Results:

• Fatty acids, particularly tetradecanoic acid, were identified as intercellular signaling molecules.
• These fatty acids activate population density-dependent expression of ddcA, crucial for P. putida root colonization.
• The signaling pathway involves the RoxS/RoxR two-component system, with P. aeruginosa signal production regulated by quorum sensing.

Conclusions:

• Fatty acids serve as key mediators of cell-cell communication in Pseudomonas.
• P. putida utilizes fatty acid signaling, similar to plant pathogens and fungi, for interacting with its environment.
• This discovery sheds light on novel mechanisms governing bacterial behavior and plant root colonization.