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do Nascimento MO, Teles Tenório AC, Sarmento RA, Melo RDCC, Della Lucia TMC, Dias Amaral K, de Souza DJ. Soil actinobacteria inhibit antagonistic fungi of leafcutter ant colonies. J Basic Microbiol 2021; 62:63-73. [PMID: 34850414 DOI: 10.1002/jobm.202100476] [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: 09/01/2021] [Revised: 11/11/2021] [Accepted: 11/20/2021] [Indexed: 11/08/2022]
Abstract
Founder females of the leaf-cutting ant species Atta sexdens experience high mortality during the founding and establishment of their colonies. The foundation site is crucial for the success of a new colony. In this study, we isolated and identified actinobacteria from fungus garden chambers of A. sexdens colony growth in soils from (1) forested areas without leafcutter ant nests and (2) open ground areas close to leafcutter ant nests. The inhibitory effect of these isolates on pathogenic fungi and the mutualistic fungus cultivated by leafcutter ants was evaluated. The 16S rRNA gene sequences were employed to identify nine selected actinobacteria species found in the soil: Streptomyces (6), Nocardia (2), and Kitasatospora (1). One Streptomyces and one Kitasatospora isolate inhibited all the tested fungi. Since there is no evidence of actinobacteria cultivation in the workers' cuticle of the Atta genus, our results corroborate the hypothesis that these workers may establish temporary adaptive symbiosis with soil microorganisms that produce antibiotic substances, living in some parts of their nest, or even inside their bodies. Pathogenic fungi are a risk factor that can be controlled by actinobacteria metabolites from soils, with minimal energy cost to the colony.
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Affiliation(s)
- Mariela O do Nascimento
- Laboratory of Symbiosis: Insects-Microorganisms-Graduate Program in Plant Production, Federal University of Tocantins, Gurupi, Tocantins, Brazil
| | - Amanda C Teles Tenório
- Laboratory of Symbiosis: Insects-Microorganisms-Graduate Program in Plant Production, Federal University of Tocantins, Gurupi, Tocantins, Brazil
| | - Renato A Sarmento
- Laboratory of Symbiosis: Insects-Microorganisms-Graduate Program in Plant Production, Federal University of Tocantins, Gurupi, Tocantins, Brazil
| | - Rita de Cássia C Melo
- Department of Microbiology, Laboratory of Mycorrhizal Associations, Federal University of Viçosa, Viçosa, Minas Gerais, Brazil
| | | | - Karina Dias Amaral
- Entomology Department, Leafcutter Ants Laboratory, Federal University of Viçosa, Viçosa, Minas Gerais, Brazil
| | - Danival J de Souza
- Laboratory of Symbiosis: Insects-Microorganisms-Graduate Program in Plant Production, Federal University of Tocantins, Gurupi, Tocantins, Brazil
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2
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Batey SFD, Greco C, Hutchings MI, Wilkinson B. Chemical warfare between fungus-growing ants and their pathogens. Curr Opin Chem Biol 2020; 59:172-181. [PMID: 32949983 PMCID: PMC7763482 DOI: 10.1016/j.cbpa.2020.08.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/28/2020] [Accepted: 08/03/2020] [Indexed: 12/19/2022]
Abstract
Fungus-growing attine ants are under constant threat from fungal pathogens such as the specialized mycoparasite Escovopsis, which uses combined physical and chemical attack strategies to prey on the fungal gardens of the ants. In defence, some species assemble protective microbiomes on their exoskeletons that contain antimicrobial-producing Actinobacteria. Underlying this network of mutualistic and antagonistic interactions are an array of chemical signals. Escovopsis weberi produces the shearinine terpene-indole alkaloids, which affect ant behaviour, diketopiperazines to combat defensive bacteria, and other small molecules that inhibit the fungal cultivar. Pseudonocardia and Streptomyces mutualist bacteria produce depsipeptide and polyene macrolide antifungals active against Escovopsis spp. The ant nest metabolome is further complicated by competition between defensive bacteria, which produce antibacterials active against even closely related species. Specialist fungal pathogens attack the nests of fungus-growing ants. Ants form mutualistic relationships with defensive actinomycete bacteria. Specialised metabolites underpin these mutualistic and antagonistic interactions.
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Affiliation(s)
- Sibyl F D Batey
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, United Kingdom
| | - Claudio Greco
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, United Kingdom
| | - Matthew I Hutchings
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, United Kingdom; School of Biological Sciences, University of East Anglia, Norwich, NR4 7TU, United Kingdom.
| | - Barrie Wilkinson
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, United Kingdom.
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3
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Calcagnile M, Tredici SM, Talà A, Alifano P. Bacterial Semiochemicals and Transkingdom Interactions with Insects and Plants. INSECTS 2019; 10:E441. [PMID: 31817999 PMCID: PMC6955855 DOI: 10.3390/insects10120441] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/02/2019] [Accepted: 12/05/2019] [Indexed: 01/08/2023]
Abstract
A peculiar feature of all living beings is their capability to communicate. With the discovery of the quorum sensing phenomenon in bioluminescent bacteria in the late 1960s, it became clear that intraspecies and interspecies communications and social behaviors also occur in simple microorganisms such as bacteria. However, at that time, it was difficult to imagine how such small organisms-invisible to the naked eye-could influence the behavior and wellbeing of the larger, more complex and visible organisms they colonize. Now that we know this information, the challenge is to identify the myriad of bacterial chemical signals and communication networks that regulate the life of what can be defined, in a whole, as a meta-organism. In this review, we described the transkingdom crosstalk between bacteria, insects, and plants from an ecological perspective, providing some paradigmatic examples. Second, we reviewed what is known about the genetic and biochemical bases of the bacterial chemical communication with other organisms and how explore the semiochemical potential of a bacterium can be explored. Finally, we illustrated how bacterial semiochemicals managing the transkingdom communication may be exploited from a biotechnological point of view.
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Affiliation(s)
| | | | | | - Pietro Alifano
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Prov.le Lecce-Monteroni, 73100 Lecce, Italy; (M.C.); (S.M.T.); (A.T.)
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Heine D, Holmes NA, Worsley SF, Santos ACA, Innocent TM, Scherlach K, Patrick EH, Yu DW, Murrell JC, Vieria PC, Boomsma JJ, Hertweck C, Hutchings MI, Wilkinson B. Chemical warfare between leafcutter ant symbionts and a co-evolved pathogen. Nat Commun 2018; 9:2208. [PMID: 29880868 PMCID: PMC5992151 DOI: 10.1038/s41467-018-04520-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/24/2018] [Indexed: 11/14/2022] Open
Abstract
Acromyrmex leafcutter ants form a mutually beneficial symbiosis with the fungus Leucoagaricus gongylophorus and with Pseudonocardia bacteria. Both are vertically transmitted and actively maintained by the ants. The fungus garden is manured with freshly cut leaves and provides the sole food for the ant larvae, while Pseudonocardia cultures are reared on the ant-cuticle and make antifungal metabolites to help protect the cultivar against disease. If left unchecked, specialized parasitic Escovopsis fungi can overrun the fungus garden and lead to colony collapse. We report that Escovopsis upregulates the production of two specialized metabolites when it infects the cultivar. These compounds inhibit Pseudonocardia and one, shearinine D, also reduces worker behavioral defenses and is ultimately lethal when it accumulates in ant tissues. Our results are consistent with an active evolutionary arms race between Pseudonocardia and Escovopsis, which modifies both bacterial and behavioral defenses such that colony collapse is unavoidable once Escovopsis infections escalate. Acromyrmex ants cultivate fungus gardens that can be parasitized by Escovopsis sp., leading to colony collapse. Here, Heine et al. identify two secondary metabolites produced by Escovopsis that accumulate in Acromyrmex tissue, reduce behavioural defenses and suppress symbiotic Pseudonocardia bacteria.
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Affiliation(s)
- Daniel Heine
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, Norfolk, NR4 7UH, UK
| | - Neil A Holmes
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK
| | - Sarah F Worsley
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK
| | - Ana Carolina A Santos
- Leibniz Institute for Natural Product Research and Infection Biology, HKI, Beutenbergstraße 11a, Jena, 07745, Germany.,Friedrich Schiller University, Jena, Germany.,Departmento de Química, Universidade Federal de São Carlos, UFSCar, Via Washington Luiz KM 235, CP 676, São Carlos, SP, Brazil
| | - Tabitha M Innocent
- Department of Biology, Centre for Social Evolution, University of Copenhagen, Universitetsparken 15, Copenhagen, 2100, Denmark
| | - Kirstin Scherlach
- Leibniz Institute for Natural Product Research and Infection Biology, HKI, Beutenbergstraße 11a, Jena, 07745, Germany
| | - Elaine H Patrick
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK
| | - Douglas W Yu
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK
| | - J Colin Murrell
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK
| | - Paulo C Vieria
- Departmento de Química, Universidade Federal de São Carlos, UFSCar, Via Washington Luiz KM 235, CP 676, São Carlos, SP, Brazil
| | - Jacobus J Boomsma
- Department of Biology, Centre for Social Evolution, University of Copenhagen, Universitetsparken 15, Copenhagen, 2100, Denmark
| | - Christian Hertweck
- Leibniz Institute for Natural Product Research and Infection Biology, HKI, Beutenbergstraße 11a, Jena, 07745, Germany.,Friedrich Schiller University, Jena, Germany
| | - Matthew I Hutchings
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK.
| | - Barrie Wilkinson
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, Norfolk, NR4 7UH, UK.
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Evolutionary stability of antibiotic protection in a defensive symbiosis. Proc Natl Acad Sci U S A 2018; 115:E2020-E2029. [PMID: 29444867 DOI: 10.1073/pnas.1719797115] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The increasing resistance of human pathogens severely limits the efficacy of antibiotics in medicine, yet many animals, including solitary beewolf wasps, successfully engage in defensive alliances with antibiotic-producing bacteria for millions of years. Here, we report on the in situ production of 49 derivatives belonging to three antibiotic compound classes (45 piericidin derivatives, 3 streptochlorin derivatives, and nigericin) by the symbionts of 25 beewolf host species and subspecies, spanning 68 million years of evolution. Despite a high degree of qualitative stability in the antibiotic mixture, we found consistent quantitative differences between species and across geographic localities, presumably reflecting adaptations to combat local pathogen communities. Antimicrobial bioassays with the three main components and in silico predictions based on the structure and specificity in polyketide synthase domains of the piericidin biosynthesis gene cluster yield insights into the mechanistic basis and ecoevolutionary implications of producing a complex mixture of antimicrobial compounds in a natural setting.
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Zeng Q, Wu S, Sukumaran J, Rodrigo A. Models of microbiome evolution incorporating host and microbial selection. MICROBIOME 2017; 5:127. [PMID: 28946894 PMCID: PMC5613328 DOI: 10.1186/s40168-017-0343-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 09/15/2017] [Indexed: 05/25/2023]
Abstract
BACKGROUND Numerous empirical studies suggest that hosts and microbes exert reciprocal selective effects on their ecological partners. Nonetheless, we still lack an explicit framework to model the dynamics of both hosts and microbes under selection. In a previous study, we developed an agent-based forward-time computational framework to simulate the neutral evolution of host-associated microbial communities in a constant-sized, unstructured population of hosts. These neutral models allowed offspring to sample microbes randomly from parents and/or from the environment. Additionally, the environmental pool of available microbes was constituted by fixed and persistent microbial OTUs and by contributions from host individuals in the preceding generation. METHODS In this paper, we extend our neutral models to allow selection to operate on both hosts and microbes. We do this by constructing a phenome for each microbial OTU consisting of a sample of traits that influence host and microbial fitnesses independently. Microbial traits can influence the fitness of hosts ("host selection") and the fitness of microbes ("trait-mediated microbial selection"). Additionally, the fitness effects of traits on microbes can be modified by their hosts ("host-mediated microbial selection"). We simulate the effects of these three types of selection, individually or in combination, on microbiome diversities and the fitnesses of hosts and microbes over several thousand generations of hosts. RESULTS We show that microbiome diversity is strongly influenced by selection acting on microbes. Selection acting on hosts only influences microbiome diversity when there is near-complete direct or indirect parental contribution to the microbiomes of offspring. Unsurprisingly, microbial fitness increases under microbial selection. Interestingly, when host selection operates, host fitness only increases under two conditions: (1) when there is a strong parental contribution to microbial communities or (2) in the absence of a strong parental contribution, when host-mediated selection acts on microbes concomitantly. CONCLUSIONS We present a computational framework that integrates different selective processes acting on the evolution of microbiomes. Our framework demonstrates that selection acting on microbes can have a strong effect on microbial diversities and fitnesses, whereas selection on hosts can have weaker outcomes.
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Affiliation(s)
- Qinglong Zeng
- Department of Biology, Duke University, Durham, NC USA
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territories Australia
| | - Steven Wu
- Biodesign Institute, Arizona State University, Tempe, AZ USA
| | - Jeet Sukumaran
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI USA
| | - Allen Rodrigo
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territories Australia
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van der Meij A, Worsley SF, Hutchings MI, van Wezel GP. Chemical ecology of antibiotic production by actinomycetes. FEMS Microbiol Rev 2017; 41:392-416. [DOI: 10.1093/femsre/fux005] [Citation(s) in RCA: 220] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 02/02/2017] [Indexed: 12/13/2022] Open
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Meirelles LA, Mendes TD, Solomon SE, Bueno OC, Pagnocca FC, Rodrigues A. Broad Escovopsis-inhibition activity of Pseudonocardia associated with Trachymyrmex ants. ENVIRONMENTAL MICROBIOLOGY REPORTS 2014; 6:339-345. [PMID: 24992532 DOI: 10.1111/1758-2229.12132] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 12/04/2013] [Indexed: 06/03/2023]
Abstract
Attine ants maintain an association with antibiotic-producing Actinobacteria found on their integuments. Evidence supports these bacteria as auxiliary symbionts that help ants to defend the fungus gardens against pathogens. Using Pseudonocardia strains isolated from Trachymyrmex ants, we tested whether the inhibitory capabilities of such strains are restricted to Escovopsis parasites that infect gardens of this ant genus. Twelve Pseudonocardia strains were tested in in vitro bioassays against Escovopsis strains derived from fungus gardens of Trachymyrmex (n = 1) and leaf-cutting ants (n = 3). Overall, significant differences were observed in the mycelial growth among each Escovopsis strain in the presence of Pseudonocardia. Particularly, Escovopsis from Acromyrmex and Trachymyrmex were the most inhibited strains in comparison to Escovopsis isolated from Atta. This result suggests that Pseudonocardia isolated from Trachymyrmex possibly secrete antimicrobial compounds effective against diverse Escovopsis strains. The fact that Trachymyrmex ants harbour Pseudonocardia strains with broad spectrum of activity and its defensive role on attine gardens are discussed.
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Affiliation(s)
- Lucas A Meirelles
- Center for the Study of Social Insects, UNESP - São Paulo State University, Rio Claro, SP, Brazil; Department of Biochemistry and Microbiology, UNESP - São Paulo State University, Rio Claro, SP, Brazil
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9
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Cyatta abscondita: taxonomy, evolution, and natural history of a new fungus-farming ant genus from Brazil. PLoS One 2013; 8:e80498. [PMID: 24260403 PMCID: PMC3829880 DOI: 10.1371/journal.pone.0080498] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 10/03/2013] [Indexed: 12/02/2022] Open
Abstract
Cyatta abscondita, a new genus and species of fungus-farming ant from Brazil, is described based on morphological study of more than 20 workers, two dealate gynes, one male, and two larvae. Ecological field data are summarized, including natural history, nest architecture, and foraging behavior. Phylogenetic analyses of DNA sequence data from four nuclear genes indicate that Cyatta abscondita is the distant sister taxon of the genus Kalathomyrmex, and that together they comprise the sister group of the remaining neoattine ants, an informal clade that includes the conspicuous and well-known leaf-cutter ants. Morphologically, Cyatta abscondita shares very few obvious character states with Kalathomyrmex. It does, however, possess a number of striking morphological features unique within the fungus-farming tribe Attini. It also shares morphological character states with taxa that span the ancestral node of the Attini. The morphology, behavior, and other biological characters of Cyatta abscondita are potentially informative about plesiomorphic character states within the fungus-farming ants and about the early evolution of ant agriculture.
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Andersen SB, Hansen LH, Sapountzis P, Sørensen SJ, Boomsma JJ. Specificity and stability of the Acromyrmex-Pseudonocardia symbiosis. Mol Ecol 2013; 22:4307-4321. [PMID: 23899369 PMCID: PMC4228762 DOI: 10.1111/mec.12380] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2012] [Revised: 04/08/2013] [Accepted: 04/18/2013] [Indexed: 12/05/2022]
Abstract
The stability of mutualistic interactions is likely to be affected by the genetic diversity of symbionts that compete for the same functional niche. Fungus-growing (attine) ants have multiple complex symbioses and thus provide ample opportunities to address questions of symbiont specificity and diversity. Among the partners are Actinobacteria of the genus Pseudonocardia that are maintained on the ant cuticle to produce antibiotics, primarily against a fungal parasite of the mutualistic gardens. The symbiosis has been assumed to be a hallmark of evolutionary stability, but this notion has been challenged by culturing and sequencing data indicating an unpredictably high diversity. We used 454 pyrosequencing of 16S rRNA to estimate the diversity of the cuticular bacterial community of the leaf-cutting ant Acromyrmex echinatior and other fungus-growing ants from Gamboa, Panama. Both field and laboratory samples of the same colonies were collected, the latter after colonies had been kept under laboratory conditions for up to 10 years. We show that bacterial communities are highly colony-specific and stable over time. The majority of colonies (25/26) had a single dominant Pseudonocardia strain, and only two strains were found in the Gamboa population across 17 years, confirming an earlier study. The microbial community on newly hatched ants consisted almost exclusively of a single strain of Pseudonocardia while other Actinobacteria were identified on older, foraging ants in varying but usually much lower abundances. These findings are consistent with recent theory predicting that mixtures of antibiotic-producing bacteria can remain mutualistic when dominated by a single vertically transmitted and resource-demanding strain.
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Affiliation(s)
- S B Andersen
- Centre for Social Evolution, Department of Biology, University of Copenhagen, 2100, Copenhagen, Denmark
| | - L H Hansen
- Molecular Microbial Ecology Group, Department of Biology, University of Copenhagen, 2100, Copenhagen, Denmark
| | - P Sapountzis
- Centre for Social Evolution, Department of Biology, University of Copenhagen, 2100, Copenhagen, Denmark
| | - S J Sørensen
- Molecular Microbial Ecology Group, Department of Biology, University of Copenhagen, 2100, Copenhagen, Denmark
| | - J J Boomsma
- Centre for Social Evolution, Department of Biology, University of Copenhagen, 2100, Copenhagen, Denmark
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11
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Scheuring I, Yu DW. How to assemble a beneficial microbiome in three easy steps. Ecol Lett 2012; 15:1300-1307. [PMID: 22913725 PMCID: PMC3507015 DOI: 10.1111/j.1461-0248.2012.01853.x] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 05/14/2012] [Accepted: 07/24/2012] [Indexed: 12/31/2022]
Abstract
There is great interest in explaining how beneficial microbiomes are assembled. Antibiotic-producing microbiomes are arguably the most abundant class of beneficial microbiome in nature, having been found on corals, arthropods, molluscs, vertebrates and plant rhizospheres. An exemplar is the attine ants, which cultivate a fungus for food and host a cuticular microbiome that releases antibiotics to defend the fungus from parasites. One explanation posits long-term vertical transmission of Pseudonocardia bacteria, which (somehow) evolve new compounds in arms-race fashion against parasites. Alternatively, attines (somehow) selectively recruit multiple, non-coevolved actinobacterial genera from the soil, enabling a 'multi-drug' strategy against parasites. We reconcile the models by showing that when hosts fuel interference competition by providing abundant resources, the interference competition favours the recruitment of antibiotic-producing (and -resistant) bacteria. This partner-choice mechanism is more effective when at least one actinobacterial symbiont is vertically transmitted or has a high immigration rate, as in disease-suppressive soils.
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Affiliation(s)
- István Scheuring
- Research Group in Theoretical Biology and Evolutionary Ecology, Department of Plant Systematics, Ecology and Theoretical Biology, Eötvös University and HAS, Pázmány P. sétány 1/C, H-1117, Budapest, Hungary
| | - Douglas W Yu
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR47TJ, UK
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12
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Seipke RF, Kaltenpoth M, Hutchings MI. Streptomycesas symbionts: an emerging and widespread theme? FEMS Microbiol Rev 2012; 36:862-76. [DOI: 10.1111/j.1574-6976.2011.00313.x] [Citation(s) in RCA: 277] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 10/20/2011] [Indexed: 12/24/2022] Open
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13
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Ant Interactions with Soil Organisms and Associated Semiochemicals. J Chem Ecol 2012; 38:728-45. [DOI: 10.1007/s10886-012-0140-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 05/03/2012] [Accepted: 05/11/2012] [Indexed: 12/17/2022]
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14
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Symbiont recruitment versus ant-symbiont co-evolution in the attine ant-microbe symbiosis. Curr Opin Microbiol 2012; 15:269-77. [PMID: 22445196 DOI: 10.1016/j.mib.2012.03.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 02/27/2012] [Accepted: 03/02/2012] [Indexed: 01/11/2023]
Abstract
The symbiosis between fungus-farming ants (Attini, Formicidae), their cultivated fungi, garden-infecting Escovopsis pathogens, and Pseudonocardia bacteria on the ant integument has been popularized as an example of ant-Escovopsis-Pseudonocardia co-evolution. Recent research could not verify earlier conclusions regarding antibiotic-secreting, integumental Pseudonocardia that co-evolve to specifically suppress Escovopsis disease in an ancient co-evolutionary arms-race. Rather than long-term association with a single, co-evolving Pseudonocardia strain, attine ants accumulate complex, dynamic biofilms on their integument and in their gardens. Emerging views are that the integumental biofilms protect the ants primarily against ant diseases, whereas garden biofilms protect primarily against garden diseases; attine ants selectively recruit ('screen in') microbes into their biofilms; and the biofilms of ants and gardens serve diverse functions beyond disease-suppression.
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15
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Seipke RF, Grüschow S, Goss RJM, Hutchings MI. Isolating antifungals from fungus-growing ant symbionts using a genome-guided chemistry approach. Methods Enzymol 2012; 517:47-70. [PMID: 23084933 DOI: 10.1016/b978-0-12-404634-4.00003-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
We describe methods used to isolate and identify antifungal compounds from actinomycete strains associated with the leaf-cutter ant Acromyrmex octospinosus. These ants use antibiotics produced by symbiotic actinomycete bacteria to protect themselves and their fungal cultivar against bacterial and fungal infections. The fungal cultivar serves as the sole food source for the ant colony, which can number up to tens of thousands of individuals. We describe how we isolate bacteria from leaf-cutter ants collected in Trinidad and analyze the antifungal compounds made by two of these strains (Pseudonocardia and Streptomyces spp.), using a combination of genome analysis, mutagenesis, and chemical isolation. These methods should be generalizable to a wide variety of insect-symbiont situations. Although more time consuming than traditional activity-guided fractionation methods, this approach provides a powerful technique for unlocking the complete biosynthetic potential of individual strains and for avoiding the problems of rediscovery of known compounds. We describe the discovery of a novel nystatin compound, named nystatin P1, and identification of the biosynthetic pathway for antimycins, compounds that were first described more than 60 years ago. We also report that disruption of two known antifungal pathways in a single Streptomyces strain has revealed a third, and likely novel, antifungal plus four more pathways with unknown products. This validates our approach, which clearly has the potential to identify numerous new compounds, even from well-characterized actinomycete strains.
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Affiliation(s)
- Ryan F Seipke
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
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16
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Archetti M, Scheuring I, Hoffman M, Frederickson ME, Pierce NE, Yu DW. Economic game theory for mutualism and cooperation. Ecol Lett 2011; 14:1300-12. [DOI: 10.1111/j.1461-0248.2011.01697.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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17
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Seipke RF, Barke J, Brearley C, Hill L, Yu DW, Goss RJM, Hutchings MI. A single Streptomyces symbiont makes multiple antifungals to support the fungus farming ant Acromyrmex octospinosus. PLoS One 2011; 6:e22028. [PMID: 21857911 PMCID: PMC3153929 DOI: 10.1371/journal.pone.0022028] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 06/13/2011] [Indexed: 11/18/2022] Open
Abstract
Attine ants are dependent on a cultivated fungus for food and use antibiotics produced by symbiotic Actinobacteria as weedkillers in their fungus gardens. Actinobacterial species belonging to the genera Pseudonocardia, Streptomyces and Amycolatopsis have been isolated from attine ant nests and shown to confer protection against a range of microfungal weeds. In previous work on the higher attine Acromyrmex octospinosus we isolated a Streptomyces strain that produces candicidin, consistent with another report that attine ants use Streptomyces-produced candicidin in their fungiculture. Here we report the genome analysis of this Streptomyces strain and identify multiple antibiotic biosynthetic pathways. We demonstrate, using gene disruptions and mass spectrometry, that this single strain has the capacity to make candicidin and multiple antimycin compounds. Although antimycins have been known for >60 years we report the sequence of the biosynthetic gene cluster for the first time. Crucially, disrupting the candicidin and antimycin gene clusters in the same strain had no effect on bioactivity against a co-evolved nest pathogen called Escovopsis that has been identified in ∼30% of attine ant nests. Since the Streptomyces strain has strong bioactivity against Escovopsis we conclude that it must make additional antifungal(s) to inhibit Escovopsis. However, candicidin and antimycins likely offer protection against other microfungal weeds that infect the attine fungal gardens. Thus, we propose that the selection of this biosynthetically prolific strain from the natural environment provides A. octospinosus with broad spectrum activity against Escovopsis and other microfungal weeds.
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Affiliation(s)
- Ryan F. Seipke
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
- * E-mail: (RFS); (MIH)
| | - Jörg Barke
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Charles Brearley
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Lionel Hill
- Metabolic Biology, John Innes Centre, Norwich Research Park, Norwich, United Kingdom
| | - Douglas W. Yu
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
- State Key Laboratory of Genetic Resources, and Evolution, Ecology, Conservation, and Environment Center, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Rebecca J. M. Goss
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Matthew I. Hutchings
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
- * E-mail: (RFS); (MIH)
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Draft genome sequence of Streptomyces strain S4, a symbiont of the leaf-cutting ant Acromyrmex octospinosus. J Bacteriol 2011; 193:4270-1. [PMID: 21685285 DOI: 10.1128/jb.05275-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptomyces spp. are common symbionts of the leaf-cutting ant species Acromyrmex octospinosus, which feeds on basidiomycete fungus leaf matter and harvests the lipid- and carbohydrate-rich gongylidia as a food source. A. octospinosus and other ant genera use antifungal compounds produced by Streptomyces spp. and other actinomycetes in order to help defend their fungal gardens from parasitic fungi. Herein, we report the draft genome sequence of Streptomyces strain S4, an antifungal-producing symbiont of A. octospinosus.
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