title: Greater Species Richness of Bacterial Skin Symbionts Better Suppresses the Amphibian Fungal Pathogen Batrachochytrium Dendrobatidis.
abstract: The symbiotic microbes that grow in and on many organisms can play important roles in protecting their hosts from pathogen infection. While species diversity has been shown to influence community function in many other natural systems, the question of how species diversity of host-associated symbiotic microbes contributes to pathogen resistance is just beginning to be explored. Understanding diversity effects on pathogen resistance could be particularly helpful in combating the fungal pathogen Batrachochytrium dendrobatidis (Bd) which has caused dramatic population declines in many amphibian species and is a major concern for amphibian conservation. Our study investigates the ability of host-associated bacteria to inhibit the proliferation of Bd when grown in experimentally assembled biofilm communities that differ in species number and composition. Six bacterial species isolated from the skin of Cascades frogs (Rana cascadae) were used to assemble bacterial biofilm communities containing 1, 2, 3, or all 6 bacterial species. Biofilm communities were grown with Bd for 7 days following inoculation. More speciose bacterial communities reduced Bd abundance more effectively. This relationship between bacterial species richness and Bd suppression appeared to be driven by dominance effects-the bacterial species that were most effective at inhibiting Bd dominated multi-species communities-and complementarity: multi-species communities inhibited Bd growth more than monocultures of constituent species. These results underscore the notion that pathogen resistance is an emergent property of microbial communities, a consideration that should be taken into account when designing probiotic treatments to reduce the impacts of infectious disease.
authors.affiliation: School of Biological Sciences, Washington State University, 14204 NE Salmon Creek Avenue, Vancouver, WA, 98686, USA. jonah.piovia-scott@wsu.edu.
authors.forename: Jonah
authors.initials: J
authors.lastname: Piovia-Scott
authors.affiliation: Department of Veterinary Medicine and Epidemiology, University of California, One Shields Avenue, Davis, CA, 95616, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Rejmanek
authors.affiliation: Department of Biology, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston, MA, 02125, USA.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Woodhams
authors.affiliation: Department of Veterinary Medicine and Epidemiology, University of California, One Shields Avenue, Davis, CA, 95616, USA.
authors.forename: S Joy
authors.initials: SJ
authors.lastname: Worth
authors.affiliation: School of Biological Sciences, Washington State University, 14204 NE Salmon Creek Avenue, Vancouver, WA, 98686, USA.
authors.forename: Heather
authors.initials: H
authors.lastname: Kenny
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, 80309, USA.
authors.forename: Valerie
authors.initials: V
authors.lastname: McKenzie
authors.affiliation: Department of Entomology, University of California, One Shields Avenue, Davis, CA, 95616, USA.
authors.forename: Sharon P
authors.initials: SP
authors.lastname: Lawler
authors.affiliation: Department of Veterinary Medicine and Epidemiology, University of California, One Shields Avenue, Davis, CA, 95616, USA.
authors.forename: Janet E
authors.initials: JE
authors.lastname: Foley
mesh_terms: D000818:Animals; D000898:Antibiosis; D001419:Bacteria; D008411:Chytridiomycota / Q000472:pathogenicity*; D011898:Ranidae / Q000382:microbiology*; D012867:Skin / Q000382:microbiology*; D013559:Symbiosis
keywords: Biofilm; Community function; Microbial symbiont; Pathogen resistance; Synergy