DOI: 10.5061/dryad.36g6r
title: Data from: Cheating and resistance to cheating in natural populations of the bacterium Pseudomonas fluorescens

description: Bacteria perform cooperative behaviours that are exploitable by
 non-cooperative cheats, and cheats frequently arise and coexist with
 cooperators in laboratory microcosms. However, evidence of competitive
 dynamics between cooperators and cheats in nature remains limited. Using
 the production of pyoverdine, an iron-scavenging molecule, and natural
 soil populations of Pseudomonas fluorescens, we found that (1)
 non-producers are present in the population; (2) they co-occur
 (&lt;1cm3) with pyoverdine producers; (3) they retain functional
 pyoverdine receptors and (4) they can utilize the pyoverdine of on average
 52% of producers. This suggests non-producers can potentially act as
 social cheats in soil: utilizing the pyoverdine of others while producing
 little or none themselves. However, we found considerable variation in the
 extent to which non-producers can exploit cooperators, as some cooperators
 appear to produce exclusive forms of pyoverdine or kill non-producers with
 toxins. We examined the consequences of this variation using theoretical
 modeling. Variance in exploitability leads to some cheats gaining
 increased fitness benefits and others decreased benefits. However, the
 absolute gain in fitness from high exploitation is lower than the drop in
 fitness from low exploitation, decreasing the mean fitness of cheats and
 subsequently lowering the proportion of cheats maintained in the
 population Our results suggest that although cooperator-cheat dynamics can
 occur in soil, a range of mechanisms can prevent non-producers from
 exploiting cooperators.
description: Data - Figures
 1a_cGrowth of each isolate
 in iron-limited media. Growth of each isolate over 24hrs (∆ODA600),
 pyoverdine production over 24hrs (∆RFU), pyoverdine production per cell
 (RFU/ODA600). Site - sampling site of each isolate. Patch - patch of each
 isolate. Status - Designated as a pyoverdine producer or
 non-producerData - Figure
 1a_c.csvData - Figure
 1bGrowth of pyoverdine
 non-producers in iron-limited and iron-replete media. Non-producer -
 non-producing isolate. OD (48hrs) - ∆OD of each replicate over 48hrs.
 Media - isolate was grown in iron-limited or iron-replete
 mediaData - Figure
 2a_2b_2c_3a_3bCross Feeding assays and
 genetic distance between isolates. Each non-producer was grown in
 iron-limited media supplemented with the supernatant of each pyoverdine
 producer in the collection. Supernatant - indicates which pyoverdine
 producer provided the supplemented supernatant. Non-producer - the
 non-producer supplemented. Proximity - Whether the supernatant came from a
 producer from the same patch or from elsewhere in the population.
 Successful Use - whether the non-producers growth in iron-limited media
 was significantly increased by supplementing with the producers
 supernatant. Unsuccessful use - whether it was not. Average growth - the
 average growth increase/decrease provided by addition of supernatant
 relative to an unsupplemented control (n=6). Genetic distance - the
 genetic distance between the non-producer and the isolate providing the
 supernatantData - Figure
 S2Level of pyoverdine in
 producer supernatant for cross-feeding experiments resulting in a
 significant growth increase (successful use) versus no significant growth
 increase (unsuccessful use) for non-producers. N=1656 cross-feeding
 assays.