The enemy of my enemy: A bacterial antagonist rescues Chlamydomonas by inactivating a toxin from a rival

In tripartite cultures, Pseudomonas fluorescens rescues Chlamydomonas reinhardtii from Pseudomonas protegens Pf-5 by reducing protegencin toxin levels, enabling algal recovery.

• Why it matters: Pairwise microbial antagonism often fails to predict outcomes in communities, where higher-order interactions can switch harm into conditional protection.
• What they did: The authors compared pairwise and tripartite cultures, then used Raman microspectroscopy to track protegencin and tested spent medium, protein extracts, and heat/protease treatments.
• The result: Protegencin levels drop with P. fluorescens spent medium or protein extracts, and heat- and protease-treatment abolish this effect, implying a heat-sensitive protein factor that inactivates the toxin.

AI summary of the abstract · may contain errors · not medical advice · read the paper.