Siderophore cheating and competition for iron in natural Pseudomonas communities. Sequencing of environmental pseudomonas isolates

We isolated 930 pseudomonads from 24 soil and 24 pond communities. Then we looked at their ability to produce siderophore pyoverdine, and whether level of pyoverdine production is linked to their phylogeny (based on 887 partial rpoD sequences). We also studied: i) non- or low producers' ability to exploit pyoverdines produced by other community members, and outcompete producers under iron limitation; ii) link between several pyoverdine-related phenotypes and different environmental factors. We also sequenced genomes of 24 isolates to understand genetic basis of no pyoverdine production and their social behaviour. Our findings indicate that in natural Pseudomonas communities there is selection for cheating and cheating resistance. Moreover, our results suggest that in environments with increased iron availability pyoverdine production can be absent because pyoverdine is not needed for iron acquisition.