Microbiology Editor's Choice: social interactions in Pseudomonas aeruginosa

Posted on September 2, 2020   by Microbiology Society

Each month, a manuscript published in our flagship journal Microbiology is chosen by a member of the Editorial Board. This month, the paper is titled 'Combinatorial quorum sensing in Pseudomonas aeruginosa allows for novel cheating strategies' and was chosen by Professor Riccardo Manganelli. 

Quorum sensing (QS) is a fascinating system evolved by bacteria to respond to cell density and represents the main mechanism at the basis of bacterial social behaviour and cooperation. However, some bacteria can evolve to cheat on their kin and evolve strategies to take advantage of social behaviour without the burden of maintaining QS. In this interesting article, Gurney and colleagues reported the evolution of a Pseudomonas aeruginosa isolate able to “circumvent metabolic incentives to cooperate and act as a combinatorial signalling cheat, with higher fitness in competition with its ancestor” opening a new perspective in the evolution of bacterial social behaviour.

Combinatorial quorum sensing in Pseudomonas aeruginosa allows for novel cheating strategies

Pseudomonas aeruginosa is a human pathogen of particular concern for the immune-compromised, such as people with cystic fibrosis. Its ability to cooperate and communicate using the cell-to-cell signalling system termed quorum sensing, makes it a focal organism for performing evolution experiments to determine how cooperation evolves and how life remains social. In our study, we evolved P. aeruginosa in a way to specifically limit cheating; but by doing this, identified a previously undescribed form of cheating. Our work demonstrates the complexity of social interactions in bacteria, highlighting the limits of our understanding of how bacterial cells cooperate to cause infection.

We spoke with the corresponding author Dr James Gurney to find out more:

What is your institution and how long have you been there?

Georgia Institute of Technology, USA.  I have been here for three years as a postdoctoral researcher and am currently on the job market for faculty positions.

What is your research area?  

Microbial evolution, quorum sensing and, more recently, the evolutionary dynamics of phage therapy. 

What inspired you to research this topic?

My PhD was on how bacteria use signals to know kin from non-kin, known as kin discrimination. We wanted to know if a bacterium would be able to change the signal it used if pushed? Once we found it did not really shift but instead overcame metabolic incentives to cooperate, we knew we had a cool, if somewhat complicated, paper. It started from a lunch time chat with my PhD supervisor about what would happen if you limited cheating in a media where cheats prosper. Turns out bacteria find new ways to cheat! 

What is the most rewarding part of your research?

Seeing other people use my work in cool new ways.

What would you be doing if you weren't a scientist?

Carpenter, shipwright or lawyer.  

Follow Dr Gurney's co-authors on Twitter: 
Sheyda Azimi
Sam Brown
Stephen Diggle