Table 1: Results of a review of the empirical literature on P. aeruginosa siderophore mutants and cheating

From: Optimised chronic infection models demonstrate that siderophore ‘cheating’ in Pseudomonas aeruginosa is context specific

ReferenceProducer strainNon-producer strainGrowth mediumSpecific test for cooperationLocation of results in publicationNon-producer start frequencyCheating observed?Notes
Griffin et al., 2004ATCC 15692 (PAO1)PA06609 (PAO9)CAA+apotransferrinYesText0.5VariableCheating was concluded on the basis of differences in density of pure vs mixed culture, relative fitness not reported.
Harrison et al., 2006ATCC 15692 (PAO1)PA06609 (PAO9)WaxwormYesFigures 3 and 40.03–0.9NoHighest reported cheat relative fitness is 1, at start frequencies0.01
Ross-Gillespie et al., 2007ATCC 15692 (PAO1)PA06609 (PAO9)CAA+apotransferrinYesFigure 30.001–0.99VariableCheating observed at starting frequencies0.1; total population density only affected at lowest start frequency
Ross-Gillespie et al., 2007ATCC 15692 (PAO1)PAO1 ΔpvdDCAA+apotransferrinYesFigure 30.001–0.99VariableCheating observed at starting frequencies of 0.001, but no effect on total population density. This mutant gains less fitness benefit from co-culture than PAO9 does
Ross-Gillespie et al., 2007UCBPP-PA14 (clinical)Spontaneous mutantCAA+apotransferrinYesFigure 30.001–0.99VariableCheating observed at start frequencies0.1, but no effects on total population density. This mutant gains less fitness benefit from co-culture than PAO9 does
Harrison et al., 2008PAO985De novo evolution experimentCAA+apotransferrin/iron,±S. aureusNoFigures 1 and 20  
Brockhurst et al., 2008ATCC 15692 (PAO1)PA06609 (PAO9)M9 minimal salts+CAA+apotransferrinNo, but raw data availableFigure 4 & raw data0.5YesCheat relative fitness in mixed culture decreases as more resources are supplied to the media (CAA concentration manipulated to alter carbohydrate and amino acid supply)
Kümmerli et al., 2009aATCC 15692 (PAO1)PA06609 (PAO9)CAA+apotransferrinYesText0.33Yes 
Kümmerli et al., 2009bATCC 15692 (PAO1)PAO1 ΔpvdDCAA+apotransferrinNo    
Kümmerli et al., 2009bATCC 15692 (PAO1)PAO1 ΔpvdDpchEFCAA+apotransferrinYesFigure 40.17–0.83YesCheat is always fitter than the wild type, even when competed at a starting frequency of 0.83.
Kümmerli et al., 2009cATCC 15692 (PAO1)PA06609 (PAO9)CAA+apotransferrinYesFigure 20.33VariableCheating is time dependent
Harrison and Buckling, 2009ATCC 15692 (PAO1)pvdF transposon mutant in MPAO1 background (PA2396-C04::ISlacZ/hah)CAA+apotransferrinNo, but raw data availableRaw data0.5NoRe-analysis of raw data reveals this mutant is less fit then the wild type in mixtures with a starting frequency of 0.5 in planktonic and biofilm culture.
Harrison and Buckling, 2009ATCC 15692 (PAO1)Clones evolved from PAO6049CAA+apotransferrinNoRaw data0.5NoMutants outcompete the wild type in planktonic mixed culture, but so does their siderophore-pruducing ancestor & they are lab adapted, growing as well as PAO1 in pure culture.
Ross-Gillespie et al., 2009ATCC 15692 (PAO1)PA06609 (PAO9)CAA+apotransferrinYesFigure 20.09No 
Ross-Gillespie et al., 2009ATCC 15692 (PAO1)PAO1 ΔpvdDCAA+apotransferrinYesFigure 20.09VariableCheating observed at high cell density only.
Ross-Gillespie et al., 2009UCBPP-PA14 (clinical isolate)Spontaneous mutantCAA+apotransferrinYesFigure 20.09VariableCheating observed at high cell density only.
Kümmerli et al., 2010ATCC 15692 (PAO1)PA06609 (PAO9)CAA+apotransferrinYesText0.5Yes 
Kümmerli and Brown, 2010ATCC 15692 (PAO1)PAO1 ΔpvdDCAA+apotransferrinYesFigure 50.5Yes 
Kümmerli and Brown, 2010PAO6049PA06609 (PAO9)CAA+apotransferrinNo    
Kümmerli and Brown, 2010Environmental isolateSpontaneous mutantCAA+apotransferrinYesFigure 50.5Yes 
Jiricny et al., 2010ATCC 15692 (PAO1)PAO1 ΔpvdDCAA+apotransferrinYesFigures 4 and 50.09Yes 
Jiricny et al., 2010ATCC 15692 (PAO1)PAO1 ΔpchEFCAA+apotransferrinNo 0.09  
Jiricny et al., 2010ATCC 15692 (PAO1)PAO1 ΔpvdDpchEFCAA+apotransferrinNo 0.09  
Jiricny et al., 201011 various isolatesSpontaneous mutantsCAA+apotransferrinYesFigures 4 and 50.09VariableCheating observed for 8/11mutants. Three non-cheats (with high pyoverdin production) may be driving the reported trend.
Harrison and Buckling, 2011PAO6049Evolved clonesCAA+apotransferrinYesFigure 10.05, 0.5VariableCheating observed at low starting frequencies for a minority of mutants (mean relative fitness=1)
Harrison and Buckling, 2011PAO1 ΔmutSEvolved clonesCAA+apotransferrinYesFigure 10.05, 0.5VariableCheating observed at low starting frequencies only for a majority of mutants, but some can cheat from a starting frequency of 0.5.
Dumas and Kümmerli, 2012ATCC 15692 (PAO1)Evolved clonesCAA+apotransferrinNoFigures 3 and 40 Pyoverdine-deficient clones evolved, but their presence did not consistently reduce population growth—some were associated with increased growth.
Dumas et al., 2013ATCC 15692 (PAO1)PAO1 ΔpvdD and ΔpvdDpchEFCAA+apotransferrinNoFigure 4Three-strain mix, each strain at 0.33 Carbon source, pH and temperature determine the relative growth advantage conferred by siderophores in monoculture. In acidic pH, ΔpvdD grows better. Report outcome of simuated competitions based on monoculture growth parameters.
Ghoul et al., 2014Cystic fibrosis isolate2x spontaneous mutantsCAAYesFigures 3 and 40.1YesMutant with reduced pyoverdine production cheats on parent strain, and is cheated on by a second spontaneous mutant with even lower pyoverdine production.
Ross-Gillespie et al., 2015PAO1 ΔpvdDPAO1 ΔpvdDpchEFCAA+apotransferrinYesFigure 20.2YesThis experiment competed a double pyoverdine/pyochelin knockouts against a single pyoverdine knockout.
Ross-Gillespie et al., 2015PAO1 ΔpchEFPAO1 ΔpvdDpchEFCAA+apotransferrinYesFigure 20.2YesThis experiment competed a double pyoverdine/pyochelin knockouts against a single pyochelin knockout.
Kümmerli et al., 2015ATC 15692 (PAO1)PAO1 ΔpvdDCAA+apotransferrinNo, but can be inferred from data suppliedFigures 1,2,30.5YesThere is a coevolutionary arms race, whereby producers become less exploitable and non-producers become better cheats. Non-producer frequency is negatively correlated with population growth. Non-producers grow less well than producers in monoculture, and contemporary pairs show relative fitness of non-producers is >1 (though graphs suggest this effect is small).
Andersen et al., 2015Cystic fibrosis isolatesCF isolatesNo cultureNoText  Cheating inferred by sequence of mutations affecting pyoverdine production and uptake. Very few mutations reported in pyoverdine biosynthetic loci and none pyochelin loci. Most mutations are in pvdS.
Ghoul et al., 2016ATCC 15692 (PA01)PA06609 (PAO9)CAA+apotransferrinYesFigures 1a and 2a0.02–0.10VariableMutant cheats only if added to producer cultures before the onset of stationary phase.
Leinweber et al., 2017ATCC 15692 (PA01)+eGFP tagPAO1 ΔpvdDpchEF+mCherry tag.CAA±apotransferrinYesFigures 1,2c and 3,Supplementary Figure S10.1, 0.5, 0.9YesMutant was fitter than the wild type in shaken liquid medium (no spatial structure) and as fit as the wild type in static medium or medium solidified with agar (spatial structure present) when apotransferrin was added, regardless of starting frequency. No cheating observed when apotransferrin was not added.
Vasse et al., 2017ATCC 15692 (PA01)PAO1 ΔpvdDCAA+apotransferrinYesSupplementary Figure S1 and Figure 10.15, 0.45, 0.75YesWhen progressively higher concentrations of gentamicin are added to the medium, mutants lose their growth disadvanatge in monoculture but gain a larger benefit from co-culture with the wild type.
  1. Abbreviation: CAA, casamino acids medium.