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Soto-Cortés E, Marroquín-Rodríguez M, Basanta MD, Maldonado-López Y, Parra-Olea G, Rebollar EA. Host Species and Environment Shape the Skin Microbiota of Mexican Axolotls. MICROBIAL ECOLOGY 2024; 87:98. [PMID: 39046491 PMCID: PMC11269437 DOI: 10.1007/s00248-024-02411-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Accepted: 07/15/2024] [Indexed: 07/25/2024]
Abstract
Skin microbiomes in amphibians are complex systems that can be influenced by biotic and abiotic factors. In this study, we examined the effect of host species and environmental conditions on the skin bacterial and fungal microbiota of four obligate paedomorphic salamander species, commonly known as axolotls (Ambystoma andersoni, A. dumerilii, A. mexicanum, and A. taylori), all of them endemic to the Trans-Mexican Volcanic Belt. We found that despite their permanent aquatic lifestyle, these species present a host-specific skin microbiota that is distinct from aquatic communities. We identified skin-associated taxa that were unique to each host species and that differentiated axolotl species based on alpha and beta diversity metrics. Moreover, we identified a set of microbial taxa that were shared across hosts with high relative abundances across skin samples. Specifically, bacterial communities were dominated by Burkholderiales and Pseudomonadales bacterial orders and Capnodiales and Pleosporales fungal orders. Host species and environmental variables collectively explained more microbial composition variation in bacteria (R2 = 0.46) in comparison to fungi (R2 = 0.2). Our results contribute to a better understanding of the factors shaping the diversity and composition of skin microbial communities in Ambystoma. Additional studies are needed to disentangle the effects of specific host associated and environmental factors that could influence the skin microbiome of these endangered species.
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Affiliation(s)
- Enrique Soto-Cortés
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | | | - Maria Delia Basanta
- Department of Biology, University of Nevada Reno, Reno, NV, USA
- Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, México
| | - Yurixhi Maldonado-López
- Cátedras CONAHCYT - Instituto de Investigaciones Sobre los Recursos Naturales, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, México
| | - Gabriela Parra-Olea
- Instituto de Biología, Universidad Nacional Autónoma de México, Mexico City, México
| | - Eria A Rebollar
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México.
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2
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Wan B, Chen G, Poon ESK, Fung HS, Lau A, Sin SYW. Environmental factors and host sex influence the skin microbiota structure of Hong Kong newt (Paramesotriton hongkongensis) in a coldspot of chytridiomycosis in subtropical East Asia. Integr Zool 2024. [PMID: 38872359 DOI: 10.1111/1749-4877.12855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2024]
Abstract
Chytridiomycosis, an infectious skin disease caused by the chytrid fungi, Batrachochytrium dendrobatidis and B. salamandrivorans, poses a significant threat to amphibian biodiversity worldwide. Antifungal bacteria found on the skin of chytrid-resistant amphibians could potentially provide defense against chytridiomycosis and lower mortality rates among resistant individuals. The Hong Kong newt (Paramesotriton hongkongensis) is native to East Asia, a region suspected to be the origin of chytrids, and has exhibited asymptomatic infection, suggesting a long-term coexistence with the chytrids. Therefore, the skin microbiota of this resistant species warrant investigation, along with other factors that can affect the microbiota. Among the 149 newts sampled in their natural habitats in Hong Kong, China, putative antifungal bacteria were found in all individuals. There were 314 amplicon sequence variants distributed over 25 genera of putative antifungal bacteria; abundant ones included Acinetobacter, Flavobacterium, and Novosphingobium spp. The skin microbiota compositions were strongly influenced by the inter-site geographical distances. Despite inter-site differences, we identified some core skin microbes across sites that could be vital to P. hongkongensis. The dominant cores included the family Comamonadaceae, family Chitinophagaceae, and class Betaproteobacteria. Moreover, habitat elevation and host sex also exhibited significant effects on skin microbiota compositions. The antifungal bacteria found on these newts offer an important resource for conservation against chytridiomycosis, such as developing probiotic treatments for susceptible species.
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Affiliation(s)
- Bowen Wan
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Guoling Chen
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Emily Shui Kei Poon
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Hon Shing Fung
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Anthony Lau
- Science Unit, Lingnan University, Hong Kong, China
| | - Simon Yung Wa Sin
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
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3
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Risely A, Byrne PG, Hoye BJ, Silla AJ. Dietary carotenoid supplementation has long-term and community-wide effects on the amphibian skin microbiome. Mol Ecol 2024; 33:e17203. [PMID: 37962103 DOI: 10.1111/mec.17203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 08/24/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023]
Abstract
The amphibian skin microbiome plays a crucial role in host immunity and pathogen defence, yet we know little about the environmental drivers of skin microbial variation across host individuals. Inter-individual variation in the availability of micro-nutrients such as dietary carotenoids, which are involved in amphibian immunity, may be one factor that influences skin microbial assembly across different life history stages. We compared the effect of four carotenoid supplementation regimes during different life stages on the adult skin microbiome using a captive population of the critically endangered southern corroboree frog, Pseudophryne corroboree. We applied 16S rRNA sequencing paired with joint-species distribution models to examine the effect of supplementation on taxon abundances. We found that carotenoid supplementation had subtle yet taxonomically widespread effects on the skin microbiome, even 4.5 years post supplementation. Supplementation during any life-history stage tended to have a positive effect on the number of bacterial taxa detected, although explanatory power was low. Some genera were sensitive to supplementation pre-metamorphosis, but most demonstrated either additive or dominant effects, whereby supplementation during one life history stage had intermediate or similar effects, respectively, to supplementation across life. Carotenoid supplementation increased abundances of taxa belonging to lactic acid bacteria, including Lactococcus and Enterococcus, a group of bacteria that have previously been linked to protection against the amphibian fungal pathogen Batrachochytrium dendrobatidis (Bd). While the fitness benefits of these microbial shifts require further study, these results suggest a fundamental relationship between nutrition and the amphibian skin microbiome which may be critical to amphibian health and the development of novel conservation strategies.
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Affiliation(s)
- A Risely
- School of Science, Engineering and Environment, Salford University, Manchester, UK
| | - Phillip G Byrne
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - Bethany J Hoye
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - Aimee J Silla
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, New South Wales, Australia
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4
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Leonhardt F, Keller A, Arranz Aveces C, Ernst R. From Alien Species to Alien Communities: Host- and Habitat-Associated Microbiomes in an Alien Amphibian. MICROBIAL ECOLOGY 2023; 86:2373-2385. [PMID: 37233803 PMCID: PMC10640505 DOI: 10.1007/s00248-023-02227-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 04/20/2023] [Indexed: 05/27/2023]
Abstract
Alien species can host diverse microbial communities. These associated microbiomes may be important in the invasion process and their analysis requires a holistic community-based approach. We analysed the skin and gut microbiome of Eleutherodactylus johnstonei from native range populations in St Lucia and exotic range populations in Guadeloupe, Colombia, and European greenhouses along with their respective environmental microbial reservoir through a 16S metabarcoding approach. We show that amphibian-associated and environmental microbial communities can be considered as meta-communities that interact in the assembly process. High proportions of bacteria can disperse between frogs and environment, while respective abundances are rather determined by niche effects driven by the microbial community source and spatial environmental properties. Environmental transmissions appeared to have higher relevance for skin than for gut microbiome composition and variation. We encourage further experimental studies to assess the implications of turnover in amphibian-associated microbial communities and potentially invasive microbiota in the context of invasion success and impacts. Within this novel framework of "nested invasions," (meta-)community ecology thinking can complement and widen the traditional perspective on biological invasions.
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Affiliation(s)
- Franziska Leonhardt
- Faculty of Biology, Technical University of Dresden, 01062, Dresden, Germany.
- Museum of Zoology, Senckenberg Natural History Collections Dresden, Königsbrücker Landstraße 159, 01109, Dresden, Germany.
| | - Alexander Keller
- Faculty of Biology, Ludwig-Maximilians-University of Munich, Geschwister-Scholl-Platz 1, 80539, München, Germany
| | - Clara Arranz Aveces
- Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, 70173, Stuttgart, Germany
| | - Raffael Ernst
- Faculty of Biology, Technical University of Dresden, 01062, Dresden, Germany.
- Museum of Zoology, Senckenberg Natural History Collections Dresden, Königsbrücker Landstraße 159, 01109, Dresden, Germany.
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5
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Ramírez-Barahona S, González-Serrano FM, Martínez-Ugalde E, Soto-Pozos A, Parra-Olea G, Rebollar EA. Host phylogeny and environment shape the diversity of salamander skin bacterial communities. Anim Microbiome 2023; 5:52. [PMID: 37828573 PMCID: PMC10571319 DOI: 10.1186/s42523-023-00271-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 10/03/2023] [Indexed: 10/14/2023] Open
Abstract
The composition and diversity of animal-associated microbial communities are shaped by multiple ecological and evolutionary processes acting at different spatial and temporal scales. Skin microbiomes are thought to be strongly influenced by the environment due to the direct interaction of the host's skin with the external media. As expected, the diversity of amphibian skin microbiomes is shaped by climate and host sampling habitats, whereas phylogenetic effects appear to be weak. However, the relative strength of phylogenetic and environmental effects on salamander skin microbiomes remains poorly understood. Here, we analysed sequence data from 1164 adult salamanders of 44 species to characterise and compare the diversity and composition of skin bacteria. We assessed the relative contribution of climate, host sampling habitat, and host phylogeny to the observed patterns of bacterial diversity. We found that bacterial alpha diversity was mainly associated with host sampling habitat and climate, but that bacterial beta diversity was more strongly associated with host taxonomy and phylogeny. This phylogenetic effect predominantly occurred at intermediate levels of host divergence (0-50 Mya). Our results support the importance of environmental factors shaping the diversity of salamander skin microbiota, but also support host phylogenetic history as a major factor shaping these bacterial communities.
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Affiliation(s)
- S Ramírez-Barahona
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - F M González-Serrano
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - E Martínez-Ugalde
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - A Soto-Pozos
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
- Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - G Parra-Olea
- Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - E A Rebollar
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico.
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Kouete MT, Bletz MC, LaBumbard BC, Woodhams DC, Blackburn DC. Parental care contributes to vertical transmission of microbes in a skin-feeding and direct-developing caecilian. Anim Microbiome 2023; 5:28. [PMID: 37189209 PMCID: PMC10184399 DOI: 10.1186/s42523-023-00243-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 03/20/2023] [Indexed: 05/17/2023] Open
Abstract
BACKGROUND Our current understanding of vertebrate skin and gut microbiomes, and their vertical transmission, remains incomplete as major lineages and varied forms of parental care remain unexplored. The diverse and elaborate forms of parental care exhibited by amphibians constitute an ideal system to study microbe transmission, yet investigations of vertical transmission among frogs and salamanders have been inconclusive. In this study, we assess bacteria transmission in Herpele squalostoma, an oviparous direct-developing caecilian in which females obligately attend juveniles that feed on their mother's skin (dermatophagy). RESULTS We used 16S rRNA amplicon-sequencing of the skin and gut of wild caught H. squalostoma individuals (males, females, including those attending juveniles) as well as environmental samples. Sourcetracker analyses revealed that juveniles obtain an important portion of their skin and gut bacteria communities from their mother. The contribution of a mother's skin to the skin and gut of her respective juveniles was much larger than that of any other bacteria source. In contrast to males and females not attending juveniles, only the skins of juveniles and their mothers were colonized by bacteria taxa Verrucomicrobiaceae, Nocardioidaceae, and Erysipelotrichaceae. In addition to providing indirect evidence for microbiome transmission linked to parental care among amphibians, our study also points to noticeable differences between the skin and gut communities of H. squalostoma and that of many frogs and salamanders, which warrants further investigation. CONCLUSION Our study is the first to find strong support for vertical bacteria transmission attributed to parental care in a direct-developing amphibian species. This suggests that obligate parental care may promote microbiome transmission in caecilians.
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Affiliation(s)
- Marcel T Kouete
- School of Natural Resources and Environment, University of Florida, Gainesville, FL, 32611, USA.
- Department of Natural History, Florida Museum of Natural History, University of Florida, Gainesville, FL, 32611, USA.
| | - Molly C Bletz
- Department of Biology, University of Massachusetts, Boston, MA, 02125, USA
| | | | - Douglas C Woodhams
- Department of Biology, University of Massachusetts, Boston, MA, 02125, USA
| | - David C Blackburn
- Department of Natural History, Florida Museum of Natural History, University of Florida, Gainesville, FL, 32611, USA
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Parr McQueen J, Gattoni K, Gendron E, Schmidt S, Sommers P, Porazinska DL. External and Internal Microbiomes of Antarctic Nematodes are Distinct, but More Similar to each other than the Surrounding Environment. J Nematol 2023; 55:20230004. [PMID: 36969543 PMCID: PMC10035304 DOI: 10.2478/jofnem-2023-0004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Indexed: 03/11/2023] Open
Abstract
Host-associated microbiomes have primarily been examined in the context of their internal microbial communities, but many animal species also contain microorganisms on external host surfaces that are important to host physiology. For nematodes, single strains of bacteria are known to adhere to the cuticle (e.g., Pasteuria penetrans), but the structure of a full external microbial community is uncertain. In prior research, we showed that internal gut microbiomes of nematodes (Plectus murrayi, Eudorylaimus antarcticus) and tardigrades from Antarctica's McMurdo Dry Valleys were distinct from the surrounding environment and primarily driven by host identity. Building on this work, we extracted an additional set of individuals containing intact external microbiomes and amplified them for 16S and 18S rRNA metabarcoding. Our results showed that external bacterial microbiomes were more diverse than internal microbiomes, but less diverse than the surrounding environment. Host-specific bacterial compositional patterns were observed, and external microbiomes were most similar to their respective internal microbiomes. However, external microbiomes were more influenced by the environment than the internal microbiomes were. Non-host eukaryotic communities were similar in diversity to internal eukaryotic communities, but exhibited more stochastic patterns of assembly compared to bacterial communities, suggesting the lack of a structured external eukaryotic microbiome. Altogether, we provide evidence that nematode and tardigrade cuticles are inhabited by robust bacterial communities that are substantially influenced by the host, albeit less so than internal microbiomes are.
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Affiliation(s)
- J. Parr McQueen
- Department of Entomology and Nematology, University of Florida, FL 32611FloridaUSA
| | - K. Gattoni
- Department of Entomology and Nematology, University of Florida, FL 32611FloridaUSA
| | - E.M.S. Gendron
- Department of Entomology and Nematology, University of Florida, FL 32611FloridaUSA
| | - S.K. Schmidt
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, CO 80309Colorado BoulderUSA
| | - P. Sommers
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, CO 80309Colorado BoulderUSA
| | - D. L. Porazinska
- Department of Entomology and Nematology, University of Florida, FL 32611FloridaUSA
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Martínez-Ugalde E, Ávila-Akerberg V, González Martínez TM, Vázquez Trejo M, Zavala Hernández D, Anaya-Morales SL, Rebollar EA. The skin microbiota of the axolotl Ambystoma altamirani is highly influenced by metamorphosis and seasonality but not by pathogen infection. Anim Microbiome 2022; 4:63. [PMID: 36503640 PMCID: PMC9743558 DOI: 10.1186/s42523-022-00215-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 10/16/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Microbiomes have been increasingly recognized as major contributors to host health and survival. In amphibians, bacterial members of the skin microbiota protect their hosts by inhibiting the growth of the fungal pathogen Batrachochytrium dendrobatidis (Bd). Even though several studies describe the influence of biotic and abiotic factors over the skin microbiota, it remains unclear how these symbiotic bacterial communities vary across time and development. This is particularly relevant for species that undergo metamorphosis as it has been shown that host physiology and ecology drastically influence diversity of the skin microbiome. RESULTS We found that the skin bacterial communities of the axolotl A. altamirani are largely influenced by the metamorphic status of the host and by seasonal variation of abiotic factors such as temperature, pH, dissolved oxygen and conductivity. Despite high Bd prevalence in these samples, the bacterial diversity of the skin microbiota did not differ between infected and non-infected axolotls, although relative abundance of particular bacteria were correlated with Bd infection intensity. CONCLUSIONS Our work shows that metamorphosis is a crucial process that shapes skin bacterial communities and that axolotls under different developmental stages respond differently to environmental seasonal variations. Moreover, this study greatly contributes to a better understanding of the factors that shape amphibian skin microbiota, especially in a largely underexplored group like axolotls (Mexican Ambystoma species).
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Affiliation(s)
| | - Víctor Ávila-Akerberg
- Instituto de Ciencias Agropecuarias y Rurales, Universidad Autónoma del Estado de México, Toluca, Mexico
| | | | | | | | - Sara Lucia Anaya-Morales
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
- Department of Biology, University of Mississippi, Oxford, MS, USA
| | - Eria A Rebollar
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico.
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9
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Abstract
Temporal changes and transmission patterns in host-associated microbial communities have important implications for host health. The diversity of amphibian skin microbial communities is associated with disease outcome in amphibians exposed to the fungal pathogen Batrachochytrium dendrobatidis (Bd). To successfully develop conservation strategies against Bd, we need a comprehensive understanding of how skin microbes are maintained and transmitted over time within populations. We used 16S rRNA sequence analysis to compare Epipedobates anthonyi frogs housed with one conspecific to frogs housed singly at four time points over the course of 1 year. We found that both α and β diversity of frog skin bacterial communities changed significantly over the course of the experiment. Specifically, we found that bacterial communities of cohabitating frogs became more similar over time. We also observed that some bacterial taxa were differentially abundant between frogs housed singly and frogs housed with a conspecific. These results suggest that conspecific contact may play a role in mediating amphibian skin microbial diversity and that turnover of skin microbial communities can occur across time. Our findings provide rationale for future studies exploring horizontal transmission as a potential mechanism of host-associated microbial maintenance in amphibians.
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Affiliation(s)
- Ariel Kruger
- Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, NJ, USA
| | - Spencer Roth
- Department of Environmental Sciences, Rutgers University, New Brunswick, NJ, USA.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
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García-Sánchez JC, Arredondo-Centeno J, Segovia-Ramírez MG, Tenorio Olvera AM, Parra-Olea G, Vredenburg VT, Rovito SM. Factors Influencing Bacterial and Fungal Skin Communities of Montane Salamanders of Central Mexico. MICROBIAL ECOLOGY 2022:10.1007/s00248-022-02049-x. [PMID: 35705744 DOI: 10.1007/s00248-022-02049-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
Host microbial communities are increasingly seen as an important component of host health. In amphibians, the first land vertebrates that are threatened by a fungal skin disease globally, our understanding of the factors influencing the microbiome of amphibian skin remains incomplete because recent studies have focused almost exclusively on bacteria, and little information exists on fungal communities associated with wild amphibian species. In this study, we describe the effects of host phylogeny, climate, geographic distance, and infection with a fungal pathogen on the composition and structure of bacterial and fungal communities in seven tropical salamander species that occur in the Trans-Mexican Volcanic Belt of Central Mexico. We find that host phylogenetic relatedness is correlated with bacterial community composition while a composite climatic variable of temperature seasonality and precipitation is significantly associated with fungal community composition. We also estimated co-occurrence networks for bacterial and fungal taxa and found differences in the degree of connectivity and the distribution of negative associations between the two networks. Our results suggest that different factors may be responsible for structuring the bacterial and fungal communities of amphibian skin and that the inclusion of fungi in future studies could shed light on important functional interactions within the microbiome.
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Affiliation(s)
- Julio César García-Sánchez
- Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Irapuato, Guanajuato, México
| | - José Arredondo-Centeno
- Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Irapuato, Guanajuato, México
- Instituto Tecnológico Superior de Irapuato, Irapuato, Guanajuato, México
| | - María Guadalupe Segovia-Ramírez
- Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Irapuato, Guanajuato, México
| | - Ariadna Marcela Tenorio Olvera
- Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Irapuato, Guanajuato, México
- Instituto Tecnológico Superior de Irapuato, Irapuato, Guanajuato, México
| | - Gabriela Parra-Olea
- Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de Mexico, México
| | - Vance T Vredenburg
- Department of Biology, San Francisco State University, San Francisco, CA, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, USA
| | - Sean M Rovito
- Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Irapuato, Guanajuato, México.
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Cowgill M, Zink AG, Sparagon W, Yap TA, Sulaeman H, Koo MS, Vredenburg VT. Social Behavior, Community Composition, Pathogen Strain, and Host Symbionts Influence Fungal Disease Dynamics in Salamanders. Front Vet Sci 2021; 8:742288. [PMID: 34938792 PMCID: PMC8687744 DOI: 10.3389/fvets.2021.742288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 10/06/2021] [Indexed: 11/29/2022] Open
Abstract
The emerging fungal pathogen, Batrachochytrium dendrobatidis (Bd), which can cause a fatal disease called chytridiomycosis, is implicated in the collapse of hundreds of host amphibian species. We describe chytridiomycosis dynamics in two co-occurring terrestrial salamander species, the Santa Lucia Mountains slender salamander, Batrachoseps luciae, and the arboreal salamander, Aneides lugubris. We (1) conduct a retrospective Bd-infection survey of specimens collected over the last century, (2) estimate present-day Bd infections in wild populations, (3) use generalized linear models (GLM) to identify biotic and abiotic correlates of infection risk, (4) investigate susceptibility of hosts exposed to Bd in laboratory trials, and (5) examine the ability of host skin bacteria to inhibit Bd in culture. Our historical survey of 2,866 specimens revealed that for most of the early 20th century (~1920–1969), Bd was not detected in either species. By the 1990s the proportion of infected specimens was 29 and 17% (B. luciae and A. lugubris, respectively), and in the 2010s it was 10 and 17%. This was similar to the number of infected samples from contemporary populations (2014–2015) at 10 and 18%. We found that both hosts experience signs of chytridiomycosis and suffered high Bd-caused mortality (88 and 71% for B. luciae and A. lugubris, respectively). Our GLM revealed that Bd-infection probability was positively correlated with intraspecific group size and proximity to heterospecifics but not to abiotic factors such as precipitation, minimum temperature, maximum temperature, mean temperature, and elevation, or to the size of the hosts. Finally, we found that both host species contain symbiotic skin-bacteria that inhibit growth of Bd in laboratory trials. Our results provide new evidence consistent with other studies showing a relatively recent Bd invasion of amphibian host populations in western North America and suggest that the spread of the pathogen may be enabled both through conspecific and heterospecific host interactions. Our results suggest that wildlife disease studies should assess host-pathogen dynamics that consider the interactions and effects of multiple hosts, as well as the historical context of pathogen invasion, establishment, and epizootic to enzootic transitions to better understand and predict disease dynamics.
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Affiliation(s)
- Mae Cowgill
- Department of Biology, San Francisco State University, San Francisco, CA, United States
| | - Andrew G Zink
- Department of Biology, San Francisco State University, San Francisco, CA, United States
| | - Wesley Sparagon
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, Department of Oceanography and Sea Grant College Program, UUniversity of Hawai'i at Mānoa, HI, United States
| | - Tiffany A Yap
- Center for Biological Diversity, Oakland, CA, United States
| | - Hasan Sulaeman
- Department of Biology, San Francisco State University, San Francisco, CA, United States
| | - Michelle S Koo
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA, United States
| | - Vance T Vredenburg
- Department of Biology, San Francisco State University, San Francisco, CA, United States.,Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA, United States
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12
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Buttimer S, Hernández-Gómez O, Rosenblum EB. Skin bacterial metacommunities of San Francisco Bay Area salamanders are structured by host genus and habitat quality. FEMS Microbiol Ecol 2021; 97:6464136. [PMID: 34918086 DOI: 10.1093/femsec/fiab162] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 12/14/2021] [Indexed: 11/13/2022] Open
Abstract
Host-associated microbial communities can influence physiological processes of macroorganisms, including contributing to infectious disease resistance. For instance, some bacteria that live on amphibian skin produce antifungal compounds that inhibit two lethal fungal pathogens, Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal). Therefore, differences in microbiome composition among host species or populations within a species can contribute to variation in susceptibility to Bd/Bsal. This study applies 16S rRNA sequencing to characterize the skin bacterial microbiomes of three widespread terrestrial salamander genera native to the western United States. Using a metacommunity structure analysis, we identified dispersal barriers for these influential bacteria between salamander families and localities. We also analyzed the effects of habitat characteristics such as percent natural cover and temperature seasonality on the microbiome. We found that certain environmental variables may influence the skin microbial communities of some salamander genera more strongly than others. Each salamander family had a somewhat distinct community of putative anti-Bd skin bacteria, suggesting that salamanders may select for a functional assembly of cutaneous symbionts that could differ in its ability to protect these amphibians from disease. Our observations raise the need to consider host identity and environmental heterogeneity during the selection of probiotics to treat wildlife diseases.
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Affiliation(s)
- Shannon Buttimer
- Department of Environmental Science, Policy, and Management - The University of California, Berkeley, Berkeley, CA, U.S.A.,Department of Biological Sciences - The University of Alabama, Tuscaloosa, AL, U.S.A
| | - Obed Hernández-Gómez
- Department of Environmental Science, Policy, and Management - The University of California, Berkeley, Berkeley, CA, U.S.A.,School of Health and Natural Sciences - Dominican University of California, San Rafael, CA, U.S.A
| | - Erica Bree Rosenblum
- Department of Environmental Science, Policy, and Management - The University of California, Berkeley, Berkeley, CA, U.S.A
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13
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Douglas AJ, Hug LA, Katzenback BA. Composition of the North American Wood Frog (Rana sylvatica) Bacterial Skin Microbiome and Seasonal Variation in Community Structure. MICROBIAL ECOLOGY 2021; 81:78-92. [PMID: 32613267 DOI: 10.1007/s00248-020-01550-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
While a number of amphibian skin microbiomes have been characterized, it is unclear how these communities might vary in response to seasonal changes in the environment and the corresponding behaviors that many amphibians exhibit. Given recent studies demonstrating the importance of the skin microbiome in frog innate immune defense against pathogens, investigating how changes in the environment impact the microbial species present will provide a better understanding of conditions that may alter host susceptibility to pathogens in their environment. We sampled the bacterial skin microbiome of North American wood frogs (Rana sylvatica) from two breeding ponds in the spring, along with the bacterial community present in their vernal breeding pools, and frogs from the nearby forest floor in the summer and fall to determine whether community composition differs by sex, vernal pond site, or temporally across season (spring, summer, fall). Taxon relative abundance data reveals a profile of bacterial phyla similar to those previously described on anuran skin, with Proteobacteria, Bacteroidetes, and Actinobacteria dominating the wood frog skin microbiome. Our results indicate that sex had no significant effect on skin microbiota diversity; however, this may be due to our limited female frog sample size. Vernal pool site had a small but significant effect on skin microbiota, but skin-associated communities were more similar to each other than to the communities observed in the frogs' respective pond water. Across seasons, diversity analyses suggest that there are significant differences between the bacterial skin microbiome of frogs from spring and summer/fall groups while the average α-diversity per frog remained consistent. These results illustrate seasonal variation in wood frog skin microbiome structure and highlight the importance of considering temporal trends in an amphibian microbiome, particularly for species whose life history requires recurrent shifts in habitat and behavior.
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Affiliation(s)
- Alexander J Douglas
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - Laura A Hug
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - Barbara A Katzenback
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
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14
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Weeks DM, Parris MJ, Brown SP. Recovery and resiliency of skin microbial communities on the southern leopard frog (Lithobates sphenocephalus) following two biotic disturbances. Anim Microbiome 2020; 2:35. [PMID: 33499962 PMCID: PMC7807490 DOI: 10.1186/s42523-020-00053-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 09/11/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Microorganisms have intimate functional relationships with invertebrate and vertebrate taxa, with the potential to drastically impact health outcomes. Perturbations that affect microbial communities residing on animals can lead to dysbiosis, a change in the functional relationship, often associated with disease. Batrachochytrium dendrobatidis (Bd), a fungal pathogen of amphibians, has been responsible for catastrophic amphibian population declines around the globe. Amphibians harbor a diverse cutaneous microbiome, including some members which are known to be antagonistic to Bd (anti-Bd). Anti-Bd microorganisms facilitate the ability of some frog populations to persist in the presence of Bd, where other populations that lack anti-Bd microorganisms have declined. Research suggests disease-antagonistic properties of the microbiome may be a function of microbial community interactions, rather than individual bacterial species. Conservation efforts have identified amphibian-associated bacteria that exhibit anti-fungal properties for use as 'probiotics' on susceptible amphibian populations. Probiotic application, usually with a single bacterial species, may benefit from a greater understanding of amphibian species-specific microbiome responses to disturbances (e.g. dysbiosis vs. recovery). We assessed microbiome responses to two microbial disturbance events over multiple time points. RESULTS Exposing Lithobates sphenocephalus (southern leopard frog) adults to the biopesticidal bacteria Bacillus thuringiensis, followed by exposure to the fungal pathogen Bd, did not have long term impacts on the microbiome. After initial shifts, microbial communities recovered and returned to a state that resembled pre-disturbance. CONCLUSIONS Our results indicate microbial communities on L. sphenocephalus are robust and resistant to permanent shifts from some disturbances. This resiliency of microbial communities may explain why L. sphenocephalus is not experiencing the population declines from Bd that impacts many other species. Conservation efforts may benefit from studies outlining amphibian species-specific microbiome responses to disturbances (e.g. dysbiosis vs. recovery). If microbial communities on a threatened amphibian species are unlikely to recover following a disturbance, additional measures may be implemented to ameliorate the impacts of physical and chemical stressors on host-associated microbial communities.
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Affiliation(s)
- Denita M Weeks
- Department of Biology, Grand Junction, Colorado Mesa University, Grand Junction, CO, 81501, USA.
| | - Matthew J Parris
- Department of Biological Sciences, The University of Memphis, Memphis, TN, 38152, USA
| | - Shawn P Brown
- Department of Biological Sciences, The University of Memphis, Memphis, TN, 38152, USA.,Center for Biodiversity Research, The University of Memphis, Memphis, TN, 38152, USA
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15
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Preuss JF, Greenspan SE, Rossi EM, Lucas Gonsales EM, Neely WJ, Valiati VH, Woodhams DC, Becker CG, Tozetti AM. Widespread Pig Farming Practice Linked to Shifts in Skin Microbiomes and Disease in Pond-Breeding Amphibians. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:11301-11312. [PMID: 32845628 DOI: 10.1021/acs.est.0c03219] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Farming practices may reshape the structure of watersheds, water quality, and the health of aquatic organisms. Nutrient enrichment from agricultural pollution increases disease pressure in many host-pathogen systems, but the mechanisms underlying this pattern are not always resolved. For example, nutrient enrichment should strongly influence pools of aquatic environmental bacteria, which has the potential to alter microbiome composition of aquatic animals and their vulnerability to disease. However, shifts in the host microbiome have received little attention as a link between nutrient enrichment and diseases of aquatic organisms. We examined nutrient enrichment through the widespread practice of integrated pig-fish farming and its effects on microbiome composition of Brazilian amphibians and prevalence of the globally distributed amphibian skin pathogen Batrachochytrium dendrobatidis (Bd). This farming system drove surges in fecal coliform bacteria, disturbing amphibian skin bacterial communities such that hosts recruited higher proportions of Bd-facilitative bacteria and carried higher Bd prevalence. Our results highlight previously overlooked connections between global trends in land use change, microbiome dysbiosis, and wildlife disease. These interactions may be particularly important for disease management in the tropics, a region with both high biodiversity and continually intensifying anthropogenic pressures on aquatic wildlife habitats.
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Affiliation(s)
- Jackson F Preuss
- Programa de Pós-Graduação em Biologia, Universidade do Vale do Rio dos Sinos, São Leopoldo, RS 93022-750, Brazil
- Departamento de Ciências da Vida, Universidade do Oeste de Santa Catarina, São Miguel do Oeste, SC 89900-000, Brazil
| | - Sasha E Greenspan
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Eliandra M Rossi
- Departamento de Ciências da Vida, Universidade do Oeste de Santa Catarina, São Miguel do Oeste, SC 89900-000, Brazil
| | - Elaine M Lucas Gonsales
- Departamento de Zootecnia e Ciências Biológicas, Universidade Federal de Santa Maria, RS 98300-000, Brazil
| | - Wesley J Neely
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Victor Hugo Valiati
- Programa de Pós-Graduação em Biologia, Universidade do Vale do Rio dos Sinos, São Leopoldo, RS 93022-750, Brazil
| | - Douglas C Woodhams
- Department of Biology, University of Massachusetts Boston, Boston, Massachusetts 02125, United States
| | - C Guilherme Becker
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Alexandro M Tozetti
- Programa de Pós-Graduação em Biologia, Universidade do Vale do Rio dos Sinos, São Leopoldo, RS 93022-750, Brazil
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16
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Bernardo-Cravo AP, Schmeller DS, Chatzinotas A, Vredenburg VT, Loyau A. Environmental Factors and Host Microbiomes Shape Host-Pathogen Dynamics. Trends Parasitol 2020; 36:616-633. [PMID: 32402837 DOI: 10.1016/j.pt.2020.04.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 04/11/2020] [Accepted: 04/11/2020] [Indexed: 12/18/2022]
Abstract
Microorganisms are increasingly recognized as ecosystem-relevant components because they affect the population dynamics of hosts. Functioning at the interface of the host and pathogen, skin and gut microbiomes are vital components of immunity. Recent work reveals a strong influence of biotic and abiotic environmental factors (including the environmental microbiome) on disease dynamics, yet the importance of the host-host microbiome-pathogen-environment interaction has been poorly reflected in theory. We use amphibians and the disease chytridiomycosis caused by the fungal pathogen Batrachochytrium dendrobatidis to show how interactions between host, host microbiome, pathogen, and the environment all affect disease outcome. Our review provides new perspectives that improve our understanding of disease dynamics and ecology by incorporating environmental factors and microbiomes into disease theory.
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Affiliation(s)
- Adriana P Bernardo-Cravo
- ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France; Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Microbiology, Permoserstrasse 15, 04318, Leipzig, Germany
| | - Dirk S Schmeller
- ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France.
| | - Antonis Chatzinotas
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Microbiology, Permoserstrasse 15, 04318, Leipzig, Germany; Leipzig University, Institute of Biology, Johannisallee 21-23, 04103 Leipzig, Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, Leipzig, 04103, Germany
| | - Vance T Vredenburg
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
| | - Adeline Loyau
- ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France; Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhütte 2, Stechlin, D-16775, Germany
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17
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Walker DM, Hill AJ, Albecker MA, McCoy MW, Grisnik M, Romer A, Grajal-Puche A, Camp C, Kelehear C, Wooten J, Rheubert J, Graham SP. Variation in the Slimy Salamander (Plethodon spp.) Skin and Gut-Microbial Assemblages Is Explained by Geographic Distance and Host Affinity. MICROBIAL ECOLOGY 2020; 79:985-997. [PMID: 31802185 DOI: 10.1007/s00248-019-01456-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 10/23/2019] [Indexed: 06/10/2023]
Abstract
A multicellular host and its microbial communities are recognized as a metaorganism-a composite unit of evolution. Microbial communities have a variety of positive and negative effects on the host life history, ecology, and evolution. This study used high-throughput amplicon sequencing to characterize the complete skin and gut microbial communities, including both bacteria and fungi, of a terrestrial salamander, Plethodon glutinosus (Family Plethodontidae). We assessed salamander populations, representing nine mitochondrial haplotypes ('clades'), for differences in microbial assemblages across 13 geographic locations in the Southeastern United States. We hypothesized that microbial assemblages were structured by both host factors and geographic distance. We found a strong correlation between all microbial assemblages at close geographic distances, whereas, as spatial distance increases, the patterns became increasingly discriminate. Network analyses revealed that gut-bacterial communities have the highest degree of connectedness across geographic space. Host salamander clade was explanatory of skin-bacterial and gut-fungal assemblages but not gut-bacterial assemblages, unless the latter were analyzed within a phylogenetic context. We also inferred the function of gut-fungal assemblages to understand how an understudied component of the gut microbiome may influence salamander life history. We concluded that dispersal limitation may in part describe patterns in microbial assemblages across space and also that the salamander host may select for skin and gut communities that are maintained over time in closely related salamander populations.
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Affiliation(s)
- Donald M Walker
- Department of Biology, Middle Tennessee State University, PO Box 60, Murfreesboro, TN, 37132, USA.
| | - Aubree J Hill
- Department of Biology, Tennessee Technological University, 1100 N. Dixie Ave, Cookeville, TN, 38505, USA
| | - Molly A Albecker
- Department of Biology, East Carolina University, Greenville, NC, 27858, USA
| | - Michael W McCoy
- Department of Biology, East Carolina University, Greenville, NC, 27858, USA
| | - Matthew Grisnik
- Department of Biology, Middle Tennessee State University, PO Box 60, Murfreesboro, TN, 37132, USA
| | - Alexander Romer
- Department of Biology, Middle Tennessee State University, PO Box 60, Murfreesboro, TN, 37132, USA
| | - Alejandro Grajal-Puche
- Department of Biology, Middle Tennessee State University, PO Box 60, Murfreesboro, TN, 37132, USA
| | - Carlos Camp
- Department of Biology, Piedmont College, 1021 Central Avenue, Demorest, GA, 30535, USA
| | - Crystal Kelehear
- Smithsonian Tropical Research Institute, Apartado, 0843-03092, Balboa, Ancon, Panama, Republic of Panama
- Department of Biology, Geology and Physical Sciences, Sul Ross State University, Alpine, TX, 79832, USA
| | - Jessica Wooten
- Department of Biology, Piedmont College, 1021 Central Avenue, Demorest, GA, 30535, USA
| | - Justin Rheubert
- Department of Natural Sciences, The University of Findlay, 1000 N. Main St, Findlay, OH, 45840, USA
| | - Sean P Graham
- Department of Biology, Geology and Physical Sciences, Sul Ross State University, Alpine, TX, 79832, USA
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18
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Hernández-Gómez O, Byrne AQ, Gunderson AR, Jenkinson TS, Noss CF, Rothstein AP, Womack MC, Rosenblum EB. Invasive vegetation affects amphibian skin microbiota and body condition. PeerJ 2020; 8:e8549. [PMID: 32117625 PMCID: PMC7035873 DOI: 10.7717/peerj.8549] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 01/12/2020] [Indexed: 12/19/2022] Open
Abstract
Invasive plants are major drivers of habitat modification and the scale of their impact is increasing globally as anthropogenic activities facilitate their spread. In California, an invasive plant genus of great concern is Eucalyptus. Eucalyptus leaves can alter soil chemistry and negatively affect underground macro- and microbial communities. Amphibians serve as excellent models to evaluate the effect of Eucalyptus invasion on ground-dwelling species as they predate on soil arthropods and incorporate soil microbes into their microbiotas. The skin microbiota is particularly important to amphibian health, suggesting that invasive plant species could ultimately affect amphibian populations. To investigate the potential for invasive vegetation to induce changes in microbial communities, we sampled microbial communities in the soil and on the skin of local amphibians. Specifically, we compared Batrachoseps attenuatus skin microbiomes in both Eucalyptus globulus (Myrtaceae) and native Quercus agriflolia (Fagaceae) dominated forests in the San Francisco Bay Area. We determined whether changes in microbial diversity and composition in both soil and Batrachoseps attenuatus skin were associated with dominant vegetation type. To evaluate animal health across vegetation types, we compared Batrachoseps attenuatus body condition and the presence/absence of the amphibian skin pathogen Batrachochytrium dendrobatidis. We found that Eucalyptus invasion had no measurable effect on soil microbial community diversity and a relatively small effect (compared to the effect of site identity) on community structure in the microhabitats sampled. In contrast, our results show that Batrachoseps attenuatus skin microbiota diversity was greater in Quercus dominated habitats. One amplicon sequence variant identified in the family Chlamydiaceae was observed in higher relative abundance among salamanders sampled in Eucalyptus dominated habitats. We also observed that Batrachoseps attenuatus body condition was higher in Quercus dominated habitats. Incidence of Batrachochytrium dendrobatidis across all individuals was very low (only one Batrachochytrium dendrobatidis positive individual). The effect on body condition demonstrates that although Eucalyptus may not always decrease amphibian abundance or diversity, it can potentially have cryptic negative effects. Our findings prompt further work to determine the mechanisms that lead to changes in the health and microbiome of native species post-plant invasion.
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Affiliation(s)
- Obed Hernández-Gómez
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, USA
| | - Allison Q. Byrne
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, USA
| | - Alex R. Gunderson
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA
| | - Thomas S. Jenkinson
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, USA
| | - Clay F. Noss
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, USA
| | - Andrew P. Rothstein
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, USA
| | - Molly C. Womack
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, USA
| | - Erica B. Rosenblum
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, USA
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19
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Garcia-Recinos L, Burrowes PA, Dominguez-Bello M. The Skin Microbiota of Eleutherodactylus Frogs: Effects of Host Ecology, Phylogeny, and Local Environment. Front Microbiol 2019; 10:2571. [PMID: 31781069 PMCID: PMC6856660 DOI: 10.3389/fmicb.2019.02571] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 10/23/2019] [Indexed: 01/08/2023] Open
Abstract
Amphibian skin microbiota has a potential protective role against diseases. However, the effects of environmental and host factors on symbiotic bacterial communities are not well understood. Caribbean frogs in the genus Eleutherodactylus represent a case of congeneric species that differ in ecological specialization by the process of adaptive radiation. For a small clade of Eleutherodactylus from Puerto Rico, we investigated the role of local environments, host species, and microhabitat in the composition of their skin microbiome. The potential congruence between microbial communities in hosts that are most closely related phylogenetically was also addressed. We hypothesized that the skin microbiota of Eleutherodactylus frogs would be mostly associated to microhabitat use, but also differ according to locality, and to a lesser extent to host species. To test this hypothesis, we swabbed the skin of a total of 98 adult individuals of seven Eleutherodactylus species distributed in two nearby localities in Puerto Rico, and sequenced the V4 region of the 16S rRNA gene. Results showed that locality had the greatest effect on determining skin bacterial communities of amphibian hosts, but this effect was stronger on the composition (based on presence/absence) than on its structure (based on sequence abundance). The most ecologically distinct host, E. cooki, and the generalist E. coqui presented, respectively, the most dissimilar and similar microbiota compared to other hosts. Host phylogeny showed a weak influence on skin microbiota. Results suggest that both local environment and ecological specialization are structuring the skin bacterial community in these Eleutherodactylus species, but that characteristics intrinsic to species may also render unique hosts the ability to maintain distinct microbiotas.
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Affiliation(s)
- Liza Garcia-Recinos
- Department of Biology, University of Puerto Rico, San Juan, Puerto Rico
- Centro de Estudios Conservacionistas, Universidad de San Carlos de Guatemala, Guatemala, Guatemala
| | | | - Maria Dominguez-Bello
- Department of Biology, University of Puerto Rico, San Juan, Puerto Rico
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, United States
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20
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Ellison S, Rovito S, Parra-Olea G, Vásquez-Almazán C, Flechas SV, Bi K, Vredenburg VT. The Influence of Habitat and Phylogeny on the Skin Microbiome of Amphibians in Guatemala and Mexico. MICROBIAL ECOLOGY 2019; 78:257-267. [PMID: 30467714 DOI: 10.1007/s00248-018-1288-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 11/06/2018] [Indexed: 06/09/2023]
Abstract
Microbial symbionts are increasingly recognized as playing a critical role in organismal health across a wide range of hosts. Amphibians are unique hosts in that their skin helps to regulate the exchange of water, ions, and gases, and it plays an active role in defense against pathogens through the synthesis of anti-microbial peptides. The microbiome of amphibian skin includes a diverse community of bacteria known to defend against pathogens, including the global pandemic lineage of Batrachochytrium dendrobatidis associated with mass amphibian die-offs. The relative influence of host phylogeny and environment in determining the composition of the amphibian skin microbiome remains poorly understood. We collected skin swabs from montane amphibians in Mexico and Guatemala, focusing on two genera of plethodontid salamanders and one genus of frogs. We used high throughput sequencing to characterize the skin bacterial microbiome and tested the impact of phylogeny and habitat on bacterial diversity. Our results show that phylogenetic history strongly influences the diversity and community structure of the total bacterial microbiome at higher taxonomic levels (between orders), but on lower scales (within genera and species), the effect of habitat predominates. These results add to a growing consensus that habitat exerts a strong effect on microbiome structure and composition, particularly at shallow phylogenetic scales.
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Affiliation(s)
- Silas Ellison
- Department of Biology, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA, 94132, USA
| | - Sean Rovito
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, 94720, USA.
- Unidad de Genómica Avanzada (Langebio), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Km 9.6 Libramiento Norte Carretera Irapuato-León, 36824, Irapuato, Guanajuato, Mexico.
| | - Gabriela Parra-Olea
- Departamento de Zoología, Insituto de Biología, Universidad Nacional Autónoma de México, CP04510, México, DF, Mexico
| | - Carlos Vásquez-Almazán
- Museo de Historia Natural y Escuela de Biología, Universidad de San Carlos, Guatemala, Guatemala
| | - Sandra V Flechas
- Department of Biological Sciences, Universidad de los Andes, AA 4976, Bogotá, Colombia
- Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Bogotá, Colombia
| | - Ke Bi
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, 94720, USA
- Computational Genomics Resource Laboratory, California Institute for Quantitative Biosciences University of California, Berkeley, CA, 94720, USA
| | - Vance T Vredenburg
- Department of Biology, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA, 94132, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, CA, 94720, USA
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21
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Medina D, Hughey MC, Walke JB, Becker MH, Pontarelli K, Sun S, Badgley B, Belden LK. Amphibian skin fungal communities vary across host species and do not correlate with infection by a pathogenic fungus. Environ Microbiol 2019; 21:2905-2920. [PMID: 31087743 DOI: 10.1111/1462-2920.14682] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 05/10/2019] [Accepted: 05/11/2019] [Indexed: 12/26/2022]
Abstract
Amphibian population declines caused by the fungus Batrachochytrium dendrobatidis (Bd) have prompted studies on the bacterial community that resides on amphibian skin. However, studies addressing the fungal portion of these symbiont communities have lagged behind. Using ITS1 amplicon sequencing, we examined the fungal portion of the skin microbiome of temperate and tropical amphibian species currently coexisting with Bd in nature. We assessed cooccurrence patterns between bacterial and fungal OTUs using a subset of samples for which bacterial 16S rRNA gene amplicon data were also available. We determined that fungal communities were dominated by members of the phyla Ascomycota and Basidiomycota, and also by Chytridiomycota in the most aquatic amphibian species. Alpha diversity of the fungal communities differed across host species, and fungal community structure differed across species and regions. However, we did not find a correlation between fungal diversity/community structure and Bd infection, though we did identify significant correlations between Bd and specific OTUs. Moreover, positive bacterial-fungal cooccurrences suggest that positive interactions between these organisms occur in the skin microbiome. Understanding the ecology of amphibian skin fungi, and their interactions with bacteria will complement our knowledge of the factors influencing community assembly and the overall function of these symbiont communities.
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Affiliation(s)
- Daniel Medina
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Myra C Hughey
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Department of Biology, Vassar College, Poughkeepsie, NY, USA
| | - Jenifer B Walke
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Department of Biology, Eastern Washington University, Cheney, WA, USA
| | - Matthew H Becker
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
| | | | - Shan Sun
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, USA.,College of Computing and Informatics, University of North Carolina at Charlotte, Charlotte, NC, USA
| | - Brian Badgley
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Lisa K Belden
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
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22
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Garcia-Longoria L, Marzal A, de Lope F, Garamszegi L. Host-parasite interaction explains variation in the prevalence of avian haemosporidians at the community level. PLoS One 2019; 14:e0205624. [PMID: 30840636 PMCID: PMC6402683 DOI: 10.1371/journal.pone.0205624] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 02/15/2019] [Indexed: 11/25/2022] Open
Abstract
Parasites are a selective force that shape host community structure and dynamics, but host communities can also influence parasitism. Understanding the dual nature from host-parasite interactions can be facilitated by quantifying the variation in parasite prevalence among host species and then comparing that variation to other ecological factors that are known to also shape host communities. Avian haemosporidian parasites (e.g. Plasmodium and Haemoproteus) are abundant and widespread representing an excellent model for the study of host-parasite interactions. Several geographic and environmental factors have been suggested to determine prevalence of avian haemosporidians in bird communities. However, it remains unknown whether host and parasite traits, represented by phylogenetic distances among species and degree of specialization in host-parasite relationships, can influence infection status. The aims of this study were to analyze factors affecting infection status in a bird community and to test whether the degree of parasite specialization on their hosts is determined by host traits. Our statistical analyses suggest that infection status is mainly determined by the interaction between host species and parasite lineages where tolerance and/or susceptibility to parasites plays an essential role. Additionally, we found that although some of the parasite lineages infected a low number of bird individuals, the species they infected were distantly related and therefore the parasites themselves should not be considered typical host specialists. Infection status was higher for generalist than for specialist parasites in some, but not all, host species. These results suggest that detected prevalence in a species mainly results from the interaction between host immune defences and parasite exploitation strategies wherein the result of an association between particular parasite lineages and particular host species is idiosyncratic.
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Affiliation(s)
- Luz Garcia-Longoria
- Departamento de Anatomía, Biología Celular y Zoología, Universidad de Extremadura, Badajoz (Spain)
- Molecular Ecology and Evolution Lab, Department of Biology, Lund University, Sölvegatan 37, Lund, Sweden
- * E-mail:
| | - Alfonso Marzal
- Departamento de Anatomía, Biología Celular y Zoología, Universidad de Extremadura, Badajoz (Spain)
| | - Florentino de Lope
- Departamento de Anatomía, Biología Celular y Zoología, Universidad de Extremadura, Badajoz (Spain)
| | - Laszlo Garamszegi
- Department of Evolutionary Ecology, Estación Biológica de Doñana-CSIC, Seville, Spain
- MTA-ELTE, Theoretical Biology and Evolutionary Ecology Research Group, Department of Plant Systematics, Ecology and Theoretical Biology, Eötvös Loránd University, Budapest, Hungary
- Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Budapest, Hungary
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23
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Griffiths SM, Harrison XA, Weldon C, Wood MD, Pretorius A, Hopkins K, Fox G, Preziosi RF, Antwis RE. Genetic variability and ontogeny predict microbiome structure in a disease-challenged montane amphibian. THE ISME JOURNAL 2018; 12:2506-2517. [PMID: 29942072 PMCID: PMC6155040 DOI: 10.1038/s41396-018-0167-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 02/09/2018] [Accepted: 03/10/2018] [Indexed: 12/21/2022]
Abstract
Amphibian populations worldwide are at risk of extinction from infectious diseases, including chytridiomycosis caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). Amphibian cutaneous microbiomes interact with Bd and can confer protective benefits to the host. The composition of the microbiome itself is influenced by many environment- and host-related factors. However, little is known about the interacting effects of host population structure, genetic variation and developmental stage on microbiome composition and Bd prevalence across multiple sites. Here we explore these questions in Amietia hymenopus, a disease-affected frog in southern Africa. We use microsatellite genotyping and 16S amplicon sequencing to show that the microbiome associated with tadpole mouthparts is structured spatially, and is influenced by host genotype and developmental stage. We observed strong genetic structure in host populations based on rivers and geographic distances, but this did not correspond to spatial patterns in microbiome composition. These results indicate that demographic and host genetic factors affect microbiome composition within sites, but different factors are responsible for host population structure and microbiome structure at the between-site level. Our results help to elucidate complex within- and among- population drivers of microbiome structure in amphibian populations. That there is a genetic basis to microbiome composition in amphibians could help to inform amphibian conservation efforts against infectious diseases.
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Affiliation(s)
- Sarah M Griffiths
- School of Science and the Environment, Manchester Metropolitan University, Manchester, UK.
| | | | - Ché Weldon
- Unit for Environmental Research and Management, Faculty of Natural Science, North-West University, Potchefstroom, South Africa
| | - Michael D Wood
- School of Environment and Life Sciences, University of Salford, Salford, UK
| | - Abigail Pretorius
- Unit for Environmental Research and Management, Faculty of Natural Science, North-West University, Potchefstroom, South Africa
| | - Kevin Hopkins
- Institute of Zoology, Zoological Society of London, London, UK
| | - Graeme Fox
- School of Science and the Environment, Manchester Metropolitan University, Manchester, UK
| | - Richard F Preziosi
- School of Science and the Environment, Manchester Metropolitan University, Manchester, UK
| | - Rachael E Antwis
- Unit for Environmental Research and Management, Faculty of Natural Science, North-West University, Potchefstroom, South Africa.
- School of Environment and Life Sciences, University of Salford, Salford, UK.
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24
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Huang CH, Yu X, Liao WB. The Expensive-Tissue Hypothesis in Vertebrates: Gut Microbiota Effect, a Review. Int J Mol Sci 2018; 19:E1792. [PMID: 29914188 PMCID: PMC6032294 DOI: 10.3390/ijms19061792] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/28/2018] [Accepted: 06/12/2018] [Indexed: 02/08/2023] Open
Abstract
The gut microbiota is integral to an organism’s digestive structure and has been shown to play an important role in producing substrates for gluconeogenesis and energy production, vasodilator, and gut motility. Numerous studies have demonstrated that variation in diet types is associated with the abundance and diversity of the gut microbiota, a relationship that plays a significant role in nutrient absorption and affects gut size. The Expensive-Tissue Hypothesis states (ETH) that the metabolic requirement of relatively large brains is offset by a corresponding reduction of the other tissues, such as gut size. However, how the trade-off between gut size and brain size in vertebrates is associated with the gut microbiota through metabolic requirements still remains unexplored. Here, we review research relating to and discuss the potential influence of gut microbiota on the ETH.
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Affiliation(s)
- Chun Hua Huang
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, Sichuan, China.
- Institute of Eco-adaptation in Amphibians and Reptiles, China West Normal University, Nanchong 637009, Sichuan, China.
| | - Xin Yu
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, Sichuan, China.
- Institute of Eco-adaptation in Amphibians and Reptiles, China West Normal University, Nanchong 637009, Sichuan, China.
| | - Wen Bo Liao
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, Sichuan, China.
- Institute of Eco-adaptation in Amphibians and Reptiles, China West Normal University, Nanchong 637009, Sichuan, China.
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25
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Catenazzi A, Flechas SV, Burkart D, Hooven ND, Townsend J, Vredenburg VT. Widespread Elevational Occurrence of Antifungal Bacteria in Andean Amphibians Decimated by Disease: A Complex Role for Skin Symbionts in Defense Against Chytridiomycosis. Front Microbiol 2018; 9:465. [PMID: 29593698 PMCID: PMC5861192 DOI: 10.3389/fmicb.2018.00465] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 02/28/2018] [Indexed: 12/23/2022] Open
Abstract
Emerging infectious disease is a growing threat to global health, and recent discoveries reveal that the microbiota dwelling on and within hosts can play an important role in health and disease. To understand the capacity of skin bacteria to protect amphibian hosts from the fungal disease chytridiomycosis caused by Batrachochytrium dendrobatidis (Bd), we isolated 192 bacterial morphotypes from the skin of 28 host species of frogs (families Bufonidae, Centrolenidae, Hemiphractidae, Hylidae, Leptodactylidae, Strabomantidae, and Telmatobiidae) collected from the eastern slopes of the Peruvian Andes (540-3,865 m a.s.l.) in the Kosñipata Valley near Manu National Park, a site where we previously documented the collapse of montane frog communities following chytridiomycosis epizootics. We obtained isolates through agar culture from skin swabs of wild frogs, and identified bacterial isolates by comparing 16S rRNA sequences against the GenBank database using BLAST. We identified 178 bacterial strains of 38 genera, including 59 bacterial species not previously reported from any amphibian host. The most common bacterial isolates were species of Pseudomonas, Paenibacillus, Chryseobacterium, Comamonas, Sphingobacterium, and Stenotrophomonas. We assayed the anti-fungal abilities of 133 bacterial isolates from 26 frog species. To test whether cutaneous bacteria might inhibit growth of the fungal pathogen, we used a local Bd strain isolated from the mouthparts of stream-dwelling tadpoles (Hypsiboas gladiator, Hylidae). We quantified Bd-inhibition in vitro with co-culture assays. We found 20 bacterial isolates that inhibited Bd growth, including three isolates not previously known for such inhibitory abilities. Anti-Bd isolates occurred on aquatic and terrestrial breeding frogs across a wide range of elevations (560-3,695 m a.s.l.). The inhibitory ability of anti-Bd isolates varied considerably. The proportion of anti-Bd isolates was lowest at mid-elevations (6%), where amphibian declines have been steepest, and among hosts that are highly susceptible to chytridiomycosis (0-14%). Among non-susceptible species, two had the highest proportion of anti-Bd isolates (40 and 45%), but one common and non-susceptible species had a low proportion (13%). In conclusion, we show that anti-Bd bacteria are widely distributed elevationally and phylogenetically across frog species that have persisted in a region where chytridiomycosis emerged, caused a devastating epizootic and continues to infect amphibians.
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Affiliation(s)
- Alessandro Catenazzi
- Department of Biological Sciences, Florida International University, Miami, FL, United States.,Department of Zoology, Southern Illinois University, Carbondale, IL, United States
| | - Sandra V Flechas
- Department of Biological Sciences, Universidad de Los Andes, Bogotá, Colombia
| | - David Burkart
- Department of Zoology, Southern Illinois University, Carbondale, IL, United States
| | - Nathan D Hooven
- Department of Zoology, Southern Illinois University, Carbondale, IL, United States
| | - Joseph Townsend
- Department of Zoology, Southern Illinois University, Carbondale, IL, United States
| | - Vance T Vredenburg
- Department of Biology, San Francisco State University, San Francisco, CA, United States
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26
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Bird AK, Prado-Irwin SR, Vredenburg VT, Zink AG. Skin Microbiomes of California Terrestrial Salamanders Are Influenced by Habitat More Than Host Phylogeny. Front Microbiol 2018; 9:442. [PMID: 29593686 PMCID: PMC5861191 DOI: 10.3389/fmicb.2018.00442] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 02/26/2018] [Indexed: 02/01/2023] Open
Abstract
A multitude of microorganisms live on and within plant and animal hosts, yet the ecology and evolution of these microbial communities remains poorly understood in many taxa. This study examined the extent to which environmental factors and host taxonomic identity explain microbiome variation within two salamander genera, Ensatina and Batrachoseps, in the family Plethodontidae. In particular, we assessed whether microbiome differentiation paralleled host genetic distance at three levels of taxonomy: genus and high and low clade levels within Ensatina eschscholtzii. We predicted that more genetically related host populations would have more similar microbiomes than more distantly related host populations. We found that salamander microbiomes possess bacterial species that are most likely acquired from their surrounding soil environment, but the relative representation of those bacterial species is significantly different on the skin of salamanders compared to soil. We found differences in skin microbiome alpha diversity among Ensatina higher and lower clade groups, as well as differences between Ensatina and Batrachoseps. We also found that relative microbiome composition (beta diversity) did vary between Ensatina lower clades, but differences were driven by only a few clades and not correlated to clade genetic distances. We conclude this difference was likely a result of Ensatina lower clades being associated with geographic location and habitat type, as salamander identity at higher taxonomic levels (genus and Ensatina higher clades) was a weak predictor of microbiome composition. These results lead us to conclude that environmental factors are likely playing a more significant role in salamander cutaneous microbiome assemblages than host-specific traits.
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Affiliation(s)
- Alicia K Bird
- Department of Biology, San Francisco State University, San Francisco, CA, United States.,Department of Evolution and Ecology, University of California, Davis, Davis, CA, United States
| | - Sofia R Prado-Irwin
- Department of Biology, San Francisco State University, San Francisco, CA, United States.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States
| | - Vance T Vredenburg
- Department of Biology, San Francisco State University, San Francisco, CA, United States
| | - Andrew G Zink
- Department of Biology, San Francisco State University, San Francisco, CA, United States
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27
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Hernández-Gómez O, Briggler JT, Williams RN. Influence of immunogenetics, sex and body condition on the cutaneous microbial communities of two giant salamanders. Mol Ecol 2018; 27:1915-1929. [PMID: 29411437 DOI: 10.1111/mec.14500] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 01/23/2018] [Accepted: 01/25/2018] [Indexed: 02/06/2023]
Abstract
The complex association between hosts and microbial symbionts requires the implementation of multiple approaches to evaluate variation in host physiology. Within amphibians, heterogeneity in immunogenetic traits and cutaneous microbiota is associated with variation in disease resistance. Ozark (Cryptobranchus alleganiensis bishopi) and eastern hellbenders (C. a. alleganiensis) provide a model system to assess variation in host traits and microbial communities. Ozark hellbenders have experienced declines throughout their range, are federally endangered and experience wound retardation that is absent in the eastern subspecies. Previous microbial investigations indicate differentiation in the composition of the skin microbiota of both hellbender subspecies, but it is not clear whether these patterns are concurrent with diversity in the major histocompatibility complex (MHC) genes. We characterized the MHC IIB and the skin microbiota of hellbenders in Missouri, where both subspecies co-occur though not sympatric. We compared the microbiota composition and MHC diversity between both subspecies and investigated whether individual-level MHC diversity, sex and body condition were associated with microbiota composition. Overall, MHC IIB diversity was lower in Ozark hellbenders compared to the eastern subspecies. Multivariate statistical comparisons identified microbiota differentiation between Ozark and eastern hellbenders. MHC IIB allele presence/absence, allele divergence, body composition and sex defined grouping of hellbender microbiotas within populations. Differentiation of the cutaneous microbiotas and MHC IIB genes between eastern and Ozark hellbenders suggests that differences exist in immunity between the two subspecies. This study demonstrates how simultaneous assessments of host genetic traits and microbiotas can inform patterns of microbial community structure in natural systems.
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Affiliation(s)
- Obed Hernández-Gómez
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN, USA
| | | | - Rod N Williams
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN, USA
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28
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Hughey MC, Pena JA, Reyes R, Medina D, Belden LK, Burrowes PA. Skin bacterial microbiome of a generalist Puerto Rican frog varies along elevation and land use gradients. PeerJ 2017; 5:e3688. [PMID: 28875068 PMCID: PMC5580383 DOI: 10.7717/peerj.3688] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 07/24/2017] [Indexed: 02/01/2023] Open
Abstract
Host-associated microbial communities are ubiquitous among animals, and serve important functions. For example, the bacterial skin microbiome of amphibians can play a role in preventing or reducing infection by the amphibian chytrid fungus, Batrachochytrium dendrobatidis. Evidence suggests that environmental bacteria likely serve as a source pool for at least some of the members of the amphibian skin bacterial community, underscoring the potential for local environmental changes to disrupt microbial community source pools that could be critical to the health of host organisms. However, few studies have assessed variation in the amphibian skin microbiome along clear environmental gradients, and so we know relatively little about how local environmental conditions influence microbiome diversity. We sampled the skin bacterial communities of Coqui frogs, Eleutherodactylus coqui (N = 77), along an elevational gradient in eastern Puerto Rico (0-875 m), with transects in two land use types: intact forest (N = 4 sites) and disturbed (N = 3 sites) forest. We found that alpha diversity (as assessed by Shannon, Simpson, and Phylogenetic Diversity indices) varied across sites, but this variation was not correlated with elevation or land use. Beta diversity (community structure), on the other hand, varied with site, elevation and land use, primarily due to changes in the relative abundance of certain bacterial OTUs (∼species) within these communities. Importantly, although microbiome diversity varied, E. coqui maintained a common core microbiota across all sites. Thus, our findings suggest that environmental conditions can influence the composition of the skin microbiome of terrestrial amphibians, but that some aspects of the microbiome remain consistent despite environmental variation.
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Affiliation(s)
- Myra C Hughey
- Department of Biological Sciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America
| | - Janelle A Pena
- Department of Biology, Universidad de Puerto Rico, San Juan, Puerto Rico
| | - Roberto Reyes
- Department of Biology, Universidad de Puerto Rico, San Juan, Puerto Rico
| | - Daniel Medina
- Department of Biological Sciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America
| | - Lisa K Belden
- Department of Biological Sciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America
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