Minimal increase in genetic diversity enhances predation resistance.
The importance of species diversity to emergent, ecological properties of communities is increasingly appreciated, but the importance of within-species genetic diversity for analogous emergent properties of populations is only just becoming apparent. Here, the properties and effects of genetic variation on predation resistance in populations were assessed and the molecular mechanism underlying these emergent effects was investigated. Using biofilms of the ubiquitous bacterium Serratia marcescens, we tested the importance of genetic diversity in defending biofilms against protozoan grazing, a main source of mortality for bacteria in all natural ecosystems. S. marcescens biofilms established from wild-type cells produce heritable, stable variants, which when experimentally combined, persist as a diverse assemblage and are significantly more resistant to grazing than either wild type or variant biofilms grown in monoculture. This diversity effect is biofilm-specific, a result of either facilitation or resource partitioning among variants, with equivalent experiments using planktonic cultures and grazers resulting in dominance by a single resistant strain. The variants studied are all the result of single nucleotide polymorphisms in one regulatory gene suggesting that the benefits of genetic diversity in clonal biofilms can occur through remarkably minimal genetic change. The findings presented here provide a new insight on the integration of genetics and population ecology, in which diversity arising through minimal changes in genotype can have major ecological implications for natural populations.
Centre for Marine Bio-Innovation, University of New South Wales, Sydney, NSW, Australia School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.
Kai S
KS
Koh
Carsten
C
Matz
Chuan H
CH
Tan
Hoang L
HL
LE
Scott A
SA
Rice
Dustin J
DJ
Marshall
Peter D
PD
Steinberg
Staffan
S
Kjelleberg
D018441:Biofilms; D004269:DNA, Bacterial / Q000235:genetics; D055786:Gene Knockout Techniques; D014644:Genetic Variation; D005828:Genetics, Population; D005838:Genotype; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D012706:Serratia marcescens / Q000235:genetics* / Q000502:physiology; D013769:Tetrahymena pyriformis / Q000502:physiology
D004269:DNA, Bacterial