Siobhán O’Brien, Adela Luján & Angus BucklingCollege of Life and Environmental Sciences, University of Exeter Cornwall Campus, UK
Email: [email protected]
Cooperative heavy-metal detoxification by P.
aeruginosa
[email protected] Microbial communities- Cambridge 28 October 2014
Braud et al. 2010. Environ Microbiol. 2: 419 – 425West SA & Buckling A. 2003 Proc.R.Soc.Lond.B 270:37 – 44.Griffin AS et al. Nature. 430 :1024 – 1027West SA et al 2007 Annu. Rev. Ecol. Evol.Syst.38:53 – 77
Fe2+
Siderophore production: A model system for studying cooperation
[email protected] Microbial communities- Cambridge 28 October 2014
Our Questions
Part 1 Part 3 Part 2
[email protected] Microbial communities- Cambridge 28 October 2014
There is a benefit to the recipientDo cooperators outcompete cheats
when grown alone?
The behaviour itself is costlyDo cheats outcompete cooperators
in competition?
How do we determine if a behaviour is altruistic?
WTWT
WTWT
WT
WT
Ch
WT
WT
ChCh
ChCh
Ch
[email protected] Microbial communities- Cambridge 28 October 2014
ChWt 1:1
Copper Sulfate
CooperatorCheat
(X12)6mM CuSO4
1. Is heavy metal detoxification by siderophores a cooperative trait?
Strains:Wt: PAO1Ch:PAO1ΔPvdΔPc
h
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1. Is heavy metal detoxification by siderophores a cooperative trait?
Cheat relative fitness ~ metal treatment: conditions: F1,89 =207.89, p < 0.001)
1. Do cooperators do better than cheats when grown alone in toxic environments? ✔
1. Do cheats outcompete cooperators in competition in toxic environments? ✔
O’Brien, Hodgson & Buckling. Social Evolution of toxic Metal Bioremediation in P. aeruginosa. 2014.Proc.R.Soc.Lond.B 281(1787)
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Experimental evolution (approx. 105 generations)WTWT
Copper IronX12
Frequency of cheats Total siderophore (pyoverdine) production
1. Is heavy metal detoxification by siderophores a cooperative trait?
[email protected] Microbial communities- Cambridge 28 October 2014
***
***
1. Is heavy metal detoxification by siderophores a cooperative trait?
Conclusion:
Copper detoxification is a social trait that actively selects for the evolution of social “cheats”.
Conclusion:
Copper detoxification is a social trait that actively selects for the evolution of social “cheats”.
O’Brien, Hodgson & Buckling. Social Evolution of toxic Metal Bioremediation in P. aeruginosa. 2014.Proc.R.Soc.Lond.B 281(1787)
[email protected] Microbial communities- Cambridge 28 October 2014
Our Questions
Part 1 Part 3 Part 2
[email protected] Microbial communities- Cambridge 28 October 2014
[email protected] Microbial communities- Cambridge 28 October 2014
How is cheat fitness affected by the presence of the soil microbial community?
Cheat (species 2)
Cooperator (species 1)
How is cheat fitness affected by the presence of the soil microbial community?
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(cheat fitness~ copper*community, p=0.03). Error bars represent +/-SE
(cheat fitness~ copper, p=0.01). Error bars represent +/-SE
Monoculture Co-culture
Cheat relati
ve fitness (w)
Cheat relati
ve fitness (w)
How is cheat fitness affected by the presence of the soil microbial community?
[email protected] Microbial communities- Cambridge 28 October 2014
-Comm. + Comm. - Comm. + Comm.
-Comm. + Comm. - Comm. + Comm.
+Cu +Cu +Cu +Cu
Summary•Heavy metal detoxification by bacterial siderophores is a cooperative behaviour, that selects for rapid evolution of social ‘cheats’
•In toxic copper soil, cheat fitness is increased in the presence of the community, but in monoculture conditions only.
•Cheats cannot ‘invade’ populations of cooperators in soil as they can in synthetic media.
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Thanks for listening!
• Angus Buckling• Dave Hodgson• Adela Luján• Florian Bayer• Elze Hesse• Eleanor Van Veen
[email protected] Microbial communities- Cambridge 28 October 2014
Cu2+
Cu2+
Cu2+
Cu2+
Cu2+Cu2+
Cu2+
Cu2+
Cu2+ Cu2+
Cheat
Cheat (species 2)
Cooperator
How is cheat fitness affected by the presence of the soil microbial community?
[email protected] Microbial communities- Cambridge 28 October 2014
(cheat fitness~ copper*community, p=0.03). Error bars represent +/-SE
(cheat fitness~ copper, p=0.01). Error bars represent +/-SE
Monoculture Co-culture
Iron-limited Toxic copper
- community <1*** <1***
+ community =1 =1
Iron-limited Toxic copper
- community <1* =1
+ community =1 =1
Cheat relati
ve fitness (w)
Cheat relati
ve fitness (w)
How is cheat fitness affected by the presence of the soil microbial community?
Mineral/proteinFe3+Fe3+
Fe3+Fe3+
transportation
Fe2+Fe2+
Siderophore production: A model system for studying cooperation
Fe3+Fe3+
siderophore producer
Fe2+Fe2+
West SA, Buckling A. 2003 Cooperation, virulence and siderophore production in bacterial parasites. Proc.R.Soc.Lond.B 270:37 – 44.Griffin AS, West SA, Buckling A. 2004 Cooperation and competition in pathogenic bacteria. Nature. 430 :1024 – 1027West SA, Diggle SP, Buckling A, Gardner A, Griffin AS. 2007 The social lives of microbes. Annu. Rev. Ecol. Evol.Syst.38:53 – 77.
[email protected] Microbial communities- Cambridge 28 October 2014
Cu2+
Cu2+
Cu2+
Cu2+Cu2+
Cu2+
Cu2+
Cu2+Cu2+
Cu2+
✗
Siderophores bind other heavy metals too…
…but don’t take them into the cell
siderophore producer
Braud A, Geoffroy V, Hoegy F, Mislin GLA, Schalk IJ. 2010 Presence of the siderophores pyoverdine and pyochelin in the extracellular medium reduces toxic metal accumulation in Pseudomonas aeruginosa and increases bacterial metal tolerance. Environ Microbiol. 2: 419 – 425
[email protected] Microbial communities- Cambridge 28 October 2014