Wait. wait. Pseudomonas aeruginosa? Huh? Isn’t that a human pathogen? Isn’t it found in soils? Indeed, the answer to both of those questions is a resounding “yes”. However, that need not limit its utility for understanding marine biogeochemistry and microbial ecology writ large. The bug is in fact found in the ocean, and because of the wealth of information related to its growth dynamics, requirements, and genetic tractability, it presents a fabulous model system to harness for ocean studies too. We just have to be careful about the kinds of questions we ask! At the moment, we proceed on multiple frontiers, utilizing for instance denitrification knockouts and reconstituting the pathway among multiple individuals to address why specialists and generalist organisms develop and thrive. We’re also using genetically modified strains that have a fluorescent protein embedded into their genomes so that if they express a denitrification gene of interest, they’ll light up and we’ll know (and what chemical cues stimulated that response!). You can see some very cool work in action published in 2021 by Zhang et al. and Smriga et al.
More work will be hitting the shelves (digital ones, does anyone buy actual magazines any more?) soon!
Pseudomonas aeruginosa growing in confinement! Images by Ciccarese et al. (in prep)