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Berasategui A, Salem H, Moller AG, Christopher Y, Vidaurre Montoya Q, Conn C, Read TD, Rodrigues A, Ziemert N, Gerardo N. Genomic insights into the evolution of secondary metabolism of Escovopsis and its allies, specialized fungal symbionts of fungus-farming ants. mSystems 2024; 9:e0057624. [PMID: 38904377 PMCID: PMC11265373 DOI: 10.1128/msystems.00576-24] [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: 04/24/2024] [Accepted: 05/14/2024] [Indexed: 06/22/2024] Open
Abstract
The metabolic intimacy of symbiosis often demands the work of specialists. Natural products and defensive secondary metabolites can drive specificity by ensuring infection and propagation across host generations. But in contrast to bacteria, little is known about the diversity and distribution of natural product biosynthetic pathways among fungi and how they evolve to facilitate symbiosis and adaptation to their host environment. In this study, we define the secondary metabolism of Escovopsis and closely related genera, symbionts in the gardens of fungus-farming ants. We ask how the gain and loss of various biosynthetic pathways correspond to divergent lifestyles. Long-read sequencing allowed us to define the chromosomal features of representative Escovopsis strains, revealing highly reduced genomes composed of seven to eight chromosomes. The genomes are highly syntenic with macrosynteny decreasing with increasing phylogenetic distance, while maintaining a high degree of mesosynteny. An ancestral state reconstruction analysis of biosynthetic pathways revealed that, while many secondary metabolites are shared with non-ant-associated Sordariomycetes, 56 pathways are unique to the symbiotic genera. Reflecting adaptation to diverging ant agricultural systems, we observe that the stepwise acquisition of these pathways mirrors the ecological radiations of attine ants and the dynamic recruitment and replacement of their fungal cultivars. As different clades encode characteristic combinations of biosynthetic gene clusters, these delineating profiles provide important insights into the possible mechanisms underlying specificity between these symbionts and their fungal hosts. Collectively, our findings shed light on the evolutionary dynamic nature of secondary metabolism in Escovopsis and its allies, reflecting adaptation of the symbionts to an ancient agricultural system.IMPORTANCEMicrobial symbionts interact with their hosts and competitors through a remarkable array of secondary metabolites and natural products. Here, we highlight the highly streamlined genomic features of attine-associated fungal symbionts. The genomes of Escovopsis species, as well as species from other symbiont genera, many of which are common with the gardens of fungus-growing ants, are defined by seven chromosomes. Despite a high degree of metabolic conservation, we observe some variation in the symbionts' potential to produce secondary metabolites. As the phylogenetic distribution of the encoding biosynthetic gene clusters coincides with attine transitions in agricultural systems, we highlight the likely role of these metabolites in mediating adaptation by a group of highly specialized symbionts.
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Affiliation(s)
- Aileen Berasategui
- Department of Biology, Emory University, Atlanta, Georgia, USA
- Cluster of Excellence-Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- Mutualisms Research Group, Max Planck Institute for Biology, Tübingen, Germany
- Amsterdam Institute for Life and Environment, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Hassan Salem
- Department of Biology, Emory University, Atlanta, Georgia, USA
- Mutualisms Research Group, Max Planck Institute for Biology, Tübingen, Germany
| | - Abraham G. Moller
- Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Yuliana Christopher
- Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, Ciudad del Saber, Panamá City, Panama
| | - Quimi Vidaurre Montoya
- Department of General and Applied Biology, São Paulo State University (UNESP), Institute of Biosciences, Rio Claro, São Paulo, Brazil
| | - Caitlin Conn
- Department of Biology, Emory University, Atlanta, Georgia, USA
- Department of Biology, Berry College, Mount Berry, Georgia, USA
| | - Timothy D. Read
- Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Andre Rodrigues
- Department of General and Applied Biology, São Paulo State University (UNESP), Institute of Biosciences, Rio Claro, São Paulo, Brazil
| | - Nadine Ziemert
- Cluster of Excellence-Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
- Translational Genome Mining for Natural Products, Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Interfaculty Institute for Biomedical Informatics (IBMI), University of Tübingen, Tübingen, Germany
| | - Nicole Gerardo
- Department of Biology, Emory University, Atlanta, Georgia, USA
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Montoya Q, Martiarena M, Rodrigues A. Taxonomy and systematics of the fungus-growing ant associate Escovopsis ( Hypocreaceae). Stud Mycol 2023; 106:349-397. [PMID: 38298572 PMCID: PMC10825746 DOI: 10.3114/sim.2023.106.06] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 09/15/2023] [Indexed: 02/02/2024] Open
Abstract
Escovopsis is a symbiont of fungus-growing ant colonies. Unstandardised taxonomy prevented the evaluation of the morphological diversity of Escovopsis for more than a century. The aim of this study is to create a standardised taxonomic framework to assess the morphological and phylogenetic diversity of Escovopsis. Therefore, to set the foundation for Escovopsis taxonomy and allow interspecific comparisons within the genus, we redescribe the ex-type cultures of Escovopsis aspergilloides, E. clavata, E. lentecrescens, E. microspora, E. moelleri, E. multiformis, and E. weberi. Thus, based on the parameters adopted in this study combined with phylogenetic analyses using five molecular markers, we synonymize E. microspora with E. weberi, and introduce 13 new species isolated from attine nests collected in Argentina, Brazil, Costa Rica, Mexico, and Panama: E. breviramosa, E. chlamydosporosa, E. diminuta, E. elongatistipitata, E. gracilis, E. maculosa, E. papillata, E. peniculiformis, E. phialicopiosa, E. pseudocylindrica, E. rectangula, E. rosisimilis, and E. spicaticlavata. Our results revealed a great interspecific morphological diversity throughout Escovopsis. Notwithstanding, colony growth rates at different temperatures, as well as vesicle shape, appear to be the most outstanding features distinguishing species in the genus. This study fills an important gap in the systematics of Escovopsis that will allow future researchers to unravel the genetic and morphological diversity and species diversification of these attine ant symbionts. Taxonomic novelties: New species: Escovopsis breviramosa Q.V. Montoya, M.J.S. Martiarena & A. Rodrigues, E. chlamydosporosa Q.V. Montoya, M.J.S. Martiarena & A. Rodrigues, E. diminuta Q.V. Montoya, M.J.S. Martiarena & A. Rodrigues, E. elongatistipitata Q.V. Montoya, M.J.S. Martiarena & A. Rodrigues, E. gracilis Q.V. Montoya, M.J.S. Martiarena & A. Rodrigues, E. maculosa Q.V. Montoya, M.J.S. Martiarena & A. Rodrigues, E. papillata Q.V. Montoya, M.J.S. Martiarena & A. Rodrigues, E. peniculiformis Q.V. Montoya, M.J.S. Martiarena & A. Rodrigues, E. phialicopiosa Q.V. Montoya, M.J.S. Martiarena & A. Rodrigues, E. pseudocylindrica Q.V. Montoya, M.J.S. Martiarena & A. Rodrigues, E. rectangula Q.V. Montoya, M.J.S. Martiarena & A. Rodrigues, E. rosisimilis Q.V. Montoya, M.J.S. Martiarena & A. Rodrigues, E. spicaticlavata Q.V. Montoya, M.J.S. Martiarena & A. Rodrigues. Citation: Montoya QV, Martiarena MJS, Rodrigues A (2023). Taxonomy and systematics of the fungus-growing ant associate Escovopsis (Hypocreaceae). Studies in Mycology 106: 349-397. doi: 10.3114/sim.2023.106.06.
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Affiliation(s)
- Q.V Montoya
- Department of General and Applied Biology, São Paulo State University (UNESP), Rio Claro, SP, Brazil
| | - M.J.S. Martiarena
- Department of General and Applied Biology, São Paulo State University (UNESP), Rio Claro, SP, Brazil
| | - A. Rodrigues
- Department of General and Applied Biology, São Paulo State University (UNESP), Rio Claro, SP, Brazil
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3
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Bringhurst B, Allert M, Greenwold M, Kellner K, Seal JN. Environments and Hosts Structure the Bacterial Microbiomes of Fungus-Gardening Ants and their Symbiotic Fungus Gardens. MICROBIAL ECOLOGY 2022:10.1007/s00248-022-02138-x. [PMID: 36344828 DOI: 10.1007/s00248-022-02138-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 10/24/2022] [Indexed: 06/16/2023]
Abstract
The fungus gardening-ant system is considered a complex, multi-tiered symbiosis, as it is composed of ants, their fungus, and microorganisms associated with either ants or fungus. We examine the bacterial microbiome of Trachymyrmex septentrionalis and Mycetomoellerius turrifex ants and their symbiotic fungus gardens, using 16S rRNA Illumina sequencing, over a region spanning approximately 350 km (east and central Texas). Typically, microorganisms can be acquired from a parent colony (vertical transmission) or from the environment (horizontal transmission). Because the symbiosis is characterized by co-dispersal of the ants and fungus, elements of both ant and fungus garden microbiome could be characterized by vertical transmission. The goals of this study were to explore how both the ant and fungus garden bacterial microbiome are acquired. The main findings were that different mechanisms appear to explain the structure the microbiomes of ants and their symbiotic fungus gardens. Ant associated microbiomes had a strong host ant signature, which could be indicative of vertical inheritance of the ant associated bacterial microbiome or an unknown mechanism of active uptake or screening. On the other hand, the bacterial microbiome of the fungus garden was more complex in that some bacterial taxa appear to be structured by the ant host species, whereas others by fungal lineage or the environment (geographic region). Thus bacteria in fungus gardens appear to be acquired both horizontally and vertically.
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Affiliation(s)
- Blake Bringhurst
- Department of Biology, University of Texas at Tyler, 3900 University Blvd, Tyler, TX, 75799, USA
| | - Mattea Allert
- Department of Biology, University of Texas at Tyler, 3900 University Blvd, Tyler, TX, 75799, USA
| | - Matthew Greenwold
- Department of Biology, University of Texas at Tyler, 3900 University Blvd, Tyler, TX, 75799, USA
| | - Katrin Kellner
- Department of Biology, University of Texas at Tyler, 3900 University Blvd, Tyler, TX, 75799, USA
| | - Jon N Seal
- Department of Biology, University of Texas at Tyler, 3900 University Blvd, Tyler, TX, 75799, USA.
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Pietrobon TDC, Kooij PW, Montoya QV, Rodrigues A. Escovopsioides nivea is a non-specific antagonistic symbiont of ant-fungal crops. FUNGAL ECOL 2022. [DOI: 10.1016/j.funeco.2022.101140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Interactions among Escovopsis, Antagonistic Microfungi Associated with the Fungus-Growing Ant Symbiosis. J Fungi (Basel) 2021; 7:jof7121007. [PMID: 34946990 PMCID: PMC8703566 DOI: 10.3390/jof7121007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/12/2021] [Accepted: 11/13/2021] [Indexed: 11/17/2022] Open
Abstract
Fungi in the genus Escovopsis (Ascomycota: Hypocreales) are prevalent associates of the complex symbiosis between fungus-growing ants (Tribe Attini), the ants' cultivated basidiomycete fungi and a consortium of both beneficial and harmful microbes found within the ants' garden communities. Some Escovopsis spp. have been shown to attack the ants' cultivated fungi, and co-infections by multiple Escovopsis spp. are common in gardens in nature. Yet, little is known about how Escovopsis strains impact each other. Since microbe-microbe interactions play a central role in microbial ecology and evolution, we conducted experiments to assay the types of interactions that govern Escovopsis-Escovopsis relationships. We isolated Escovopsis strains from the gardens of 10 attine ant genera representing basal (lower) and derived groups in the attine ant phylogeny. We conducted in vitro experiments to determine the outcome of both intraclonal and interclonal Escovopsis confrontations. When paired with self (intraclonal interactions), Escovopsis isolated from lower attine colonies exhibited antagonistic (inhibitory) responses, while strains isolated from derived attine colonies exhibited neutral or mutualistic interactions, leading to a clear phylogenetic pattern of interaction outcome. Interclonal interactions were more varied, exhibiting less phylogenetic signal. These results can serve as the basis for future studies on the costs and benefits of Escovopsis coinfection, and on the genetic and chemical mechanisms that regulate the compatibility and incompatibility observed here.
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6
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Beigel K, Matthews AE, Kellner K, Pawlik CV, Greenwold M, Seal JN. Cophylogenetic analyses of Trachymyrmex ant-fungal specificity: "One to one with some exceptions". Mol Ecol 2021; 30:5605-5620. [PMID: 34424571 DOI: 10.1111/mec.16140] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 08/05/2021] [Accepted: 08/11/2021] [Indexed: 01/18/2023]
Abstract
Over the past few decades, large-scale phylogenetic analyses of fungus-gardening ants and their symbiotic fungi have depicted strong concordance among major clades of ants and their symbiotic fungi, yet within clades, fungus sharing is widespread among unrelated ant lineages. Sharing has been explained using a diffuse coevolution model within major clades. Understanding horizontal exchange within clades has been limited by conventional genetic markers that lack both interspecific and geographic variation. To examine whether reports of horizontal exchange were indeed due to symbiont sharing or the result of employing relatively uninformative molecular markers, samples of Trachymyrmex arizonensis and Trachymyrmex pomonae and their fungi were collected from native populations in Arizona and genotyped using conventional marker genes and genome-wide single nucleotide polymorphisms (SNPs). Conventional markers of the fungal symbionts generally exhibited cophylogenetic patterns that were consistent with some symbiont sharing, but most fungal clades had low support. SNP analysis, in contrast, indicated that each ant species exhibited fidelity to its own fungal subclade with only one instance of a colony growing a fungus that was otherwise associated with a different ant species. This evidence supports a pattern of codivergence between Trachymyrmex species and their fungi, and thus a diffuse coevolutionary model may not accurately predict symbiont exchange. These results suggest that fungal sharing across host species in these symbioses may be less extensive than previously thought.
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Affiliation(s)
- Katherine Beigel
- Department of Biology, The University of Texas at Tyler, Tyler, Texas, USA
| | - Alix E Matthews
- Department of Biology, The University of Texas at Tyler, Tyler, Texas, USA.,College of Sciences and Mathematics and Molecular Biosciences Program, Arkansas State University, Jonesboro, Arkansas, USA
| | - Katrin Kellner
- Department of Biology, The University of Texas at Tyler, Tyler, Texas, USA
| | - Christine V Pawlik
- Department of Biology, The University of Texas at Tyler, Tyler, Texas, USA
| | - Matthew Greenwold
- Department of Biology, The University of Texas at Tyler, Tyler, Texas, USA
| | - Jon N Seal
- Department of Biology, The University of Texas at Tyler, Tyler, Texas, USA
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7
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Montoya QV, Martiarena MJS, Bizarria R, Gerardo NM, Rodrigues A. Fungi inhabiting attine ant colonies: reassessment of the genus Escovopsis and description of Luteomyces and Sympodiorosea gens. nov. IMA Fungus 2021; 12:23. [PMID: 34429165 PMCID: PMC8383443 DOI: 10.1186/s43008-021-00078-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 08/10/2021] [Indexed: 11/15/2022] Open
Abstract
Escovopsis is a diverse group of fungi, which are considered specialized parasites of the fungal cultivars of fungus-growing ants. The lack of a suitable taxonomic framework and phylogenetic inconsistencies have long hampered Escovopsis research. The aim of this study is to reassess the genus Escovopsis using a taxonomic approach and a comprehensive multilocus phylogenetic analysis, in order to set the basis of the genus systematics and the stage for future Escovopsis research. Our results support the separation of Escovopsis into three distinct genera. In light of this, we redefine Escovopsis as a monophyletic clade whose main feature is to form terminal vesicles on conidiophores. Consequently, E. kreiselii and E. trichodermoides were recombined into two new genera, Sympodiorosea and Luteomyces, as S. kreiselii and L. trichodermoides, respectively. This study expands our understanding of the systematics of Escovopsis and related genera, thereby facilitating future research on the evolutionary history, taxonomic diversity, and ecological roles of these inhabitants of the attine ant colonies.
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Affiliation(s)
- Quimi Vidaurre Montoya
- Department of General and Applied Biology, São Paulo State University (UNESP), Avenida 24-A, n. 1515, Bela Vista, Rio Claro, SP, 13.506-900, Brazil. .,Center for the Study of Social Insects, São Paulo State University (UNESP), Rio Claro, SP, Brazil.
| | - Maria Jesus Sutta Martiarena
- Department of General and Applied Biology, São Paulo State University (UNESP), Avenida 24-A, n. 1515, Bela Vista, Rio Claro, SP, 13.506-900, Brazil.,Center for the Study of Social Insects, São Paulo State University (UNESP), Rio Claro, SP, Brazil
| | - Rodolfo Bizarria
- Department of General and Applied Biology, São Paulo State University (UNESP), Avenida 24-A, n. 1515, Bela Vista, Rio Claro, SP, 13.506-900, Brazil.,Center for the Study of Social Insects, São Paulo State University (UNESP), Rio Claro, SP, Brazil
| | - Nicole Marie Gerardo
- Department of Biology, O. Wayne Rollins Research Center, Emory University, Atlanta, USA
| | - Andre Rodrigues
- Department of General and Applied Biology, São Paulo State University (UNESP), Avenida 24-A, n. 1515, Bela Vista, Rio Claro, SP, 13.506-900, Brazil. .,Center for the Study of Social Insects, São Paulo State University (UNESP), Rio Claro, SP, Brazil.
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8
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Jiménez-Gómez I, Barcoto MO, Montoya QV, Goes AC, Monteiro LSVE, Bueno OC, Rodrigues A. Host Susceptibility Modulates Escovopsis Pathogenic Potential in the Fungiculture of Higher Attine Ants. Front Microbiol 2021; 12:673444. [PMID: 34194409 PMCID: PMC8238408 DOI: 10.3389/fmicb.2021.673444] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 05/14/2021] [Indexed: 12/17/2022] Open
Abstract
Health and disease emerge from intricate interactions between genotypes, phenotypes, and environmental features. The outcomes of such interactions are context-dependent, existing as a dynamic continuum ranging from benefits to damage. In host-microbial interactions, both the host and environmental conditions modulate the pathogenic potential of a microorganism. Microbial interactions are the core of the agricultural systems of ants in the subtribe Attina, which cultivate basidiomycete fungi for food. The fungiculture environment harbors a diverse microbial community, including fungi in the genus Escovopsis that has been studied as damage-causing agent. Here, we consider the ant colony as a host and investigate to what extent its health impacts the dynamics and outcomes of host-Escovopsis interactions. We found that different ant fungal cultivars vary in susceptibility to the same Escovopsis strains in plate-assays interactions. In subcolony-Escovopsis interactions, while healthy subcolonies gradually recover from infection with different concentrations of Escovopsis conidia, insecticide-treated subcolonies evidenced traits of infection and died within 7 days. The opportunistic nature of Escovopsis infections indicates that diseases in attine fungiculture are a consequence of host susceptibility, rather than the effect of a single microbial agent. By addressing the host susceptibility as a major modulator of Escovopsis pathogenesis, our findings expand the understanding of disease dynamics within attine colonies.
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Affiliation(s)
- Irina Jiménez-Gómez
- Department of General and Applied Biology, São Paulo State University (UNESP), Rio Claro, Brazil.,Centro de Investigación en Dinámica Celular, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | - Mariana O Barcoto
- Department of General and Applied Biology, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Quimi V Montoya
- Department of General and Applied Biology, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Aryel C Goes
- Department of General and Applied Biology, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Lana S V E Monteiro
- Department of General and Applied Biology, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Odair C Bueno
- Department of General and Applied Biology, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Andre Rodrigues
- Department of General and Applied Biology, São Paulo State University (UNESP), Rio Claro, Brazil
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9
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Christopher Y, Wcislo WT, Martínez‐Luis S, Hughes WO, Gerardo NM, Fernández‐Marín H. Disease management in two sympatric Apterostigma fungus-growing ants for controlling the parasitic fungus Escovopsis. Ecol Evol 2021; 11:6041-6052. [PMID: 34141201 PMCID: PMC8207340 DOI: 10.1002/ece3.7379] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 01/31/2021] [Accepted: 02/16/2021] [Indexed: 12/25/2022] Open
Abstract
Antagonistic interactions between host and parasites are often embedded in networks of interacting species, in which hosts may be attacked by competing parasites species, and parasites may infect more than one host species. To better understand the evolution of host defenses and parasite counterdefenses in the context of a multihost, multiparasite system, we studied two sympatric species, of congeneric fungus-growing ants (Attini) species and their symbiotic fungal cultivars, which are attacked by multiple morphotypes of parasitic fungi in the genus, Escovopsis. To assess whether closely related ant species and their cultured fungi are evolving defenses against the same or different parasitic strains, we characterized Escovopsis that were isolated from colonies of sympatric Apterostigma dentigerum and A. pilosum. We assessed in vitro and in vivo interactions of these parasites with their hosts. While the ant cultivars are parasitized by similar Escovopsis spp., the frequency of infection by these pathogens differs between the two ant species. The ability of the host fungi to suppress Escovopsis growth, as well as ant defensive responses toward the parasites, differs depending on the parasite strain and on the host ant species.
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Affiliation(s)
- Yuliana Christopher
- Centro de Biodiversidad y Descubrimiento de DrogasInstituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP)ClaytonRepública de Panamá
- Department of BiotechnologyAcharya Nagarjuna UniversityGunturIndia
- Smithsonian Tropical Research InstitutePanamaRepública de Panamá
| | | | - Sergio Martínez‐Luis
- Centro de Biodiversidad y Descubrimiento de DrogasInstituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP)ClaytonRepública de Panamá
| | | | | | - Hermógenes Fernández‐Marín
- Centro de Biodiversidad y Descubrimiento de DrogasInstituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP)ClaytonRepública de Panamá
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10
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Bizarria R, Nagamoto NS, Rodrigues A. Lack of fungal cultivar fidelity and low virulence of Escovopsis trichodermoides. FUNGAL ECOL 2020. [DOI: 10.1016/j.funeco.2020.100944] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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11
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Goes AC, Barcoto MO, Kooij PW, Bueno OC, Rodrigues A. How Do Leaf-Cutting Ants Recognize Antagonistic Microbes in Their Fungal Crops? Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00095] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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12
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Caldera EJ, Chevrette MG, McDonald BR, Currie CR. Local Adaptation of Bacterial Symbionts within a Geographic Mosaic of Antibiotic Coevolution. Appl Environ Microbiol 2019; 85:e01580-19. [PMID: 31676475 PMCID: PMC6881802 DOI: 10.1128/aem.01580-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 09/22/2019] [Indexed: 12/19/2022] Open
Abstract
The geographic mosaic theory of coevolution (GMC) posits that coevolutionary dynamics go beyond local coevolution and are comprised of the following three components: geographic selection mosaics, coevolutionary hot spots, and trait remixing. It is unclear whether the GMC applies to bacteria, as horizontal gene transfer and cosmopolitan dispersal may violate theoretical assumptions. Here, we test key GMC predictions in an antibiotic-producing bacterial symbiont (genus Pseudonocardia) that protects the crops of neotropical fungus-farming ants (Apterostigma dentigerum) from a specialized pathogen (genus Escovopsis). We found that Pseudonocardia antibiotic inhibition of common Escovopsis pathogens was elevated in A. dentigerum colonies from Panama compared to those from Costa Rica. Furthermore, a Panama Canal Zone population of Pseudonocardia on Barro Colorado Island (BCI) was locally adapted, whereas two neighboring populations were not, consistent with a GMC-predicted selection mosaic and a hot spot of adaptation surrounded by areas of maladaptation. Maladaptation was shaped by incongruent Pseudonocardia-Escovopsis population genetic structure, whereas local adaptation was facilitated by geographic isolation on BCI after the flooding of the Panama Canal. Genomic assessments of antibiotic potential of 29 Pseudonocardia strains identified diverse and unique biosynthetic gene clusters in BCI strains despite low genetic diversity in the core genome. The strength of antibiotic inhibition was not correlated with the presence/absence of individual biosynthetic gene clusters or with parasite location. Rather, biosynthetic gene clusters have undergone selective sweeps, suggesting that the trait remixing dynamics conferring the long-term maintenance of antibiotic potency rely on evolutionary genetic changes within already-present biosynthetic gene clusters and not simply on the horizontal acquisition of novel genetic elements or pathways.IMPORTANCE Recently, coevolutionary theory in macroorganisms has been advanced by the geographic mosaic theory of coevolution (GMC), which considers how geography and local adaptation shape coevolutionary dynamics. Here, we test GMC in an ancient symbiosis in which the ant Apterostigma dentigerum cultivates fungi in an agricultural system analogous to human farming. The cultivars are parasitized by the fungus Escovopsis The ants maintain symbiotic actinobacteria with antibiotic properties that help combat Escovopsis infection. This antibiotic symbiosis has persisted for tens of millions of years, raising the question of how antibiotic potency is maintained over these time scales. Our study tests the GMC in a bacterial defensive symbiosis and in a multipartite symbiosis framework. Our results show that this multipartite symbiotic system conforms to the GMC and demonstrate that this theory is applicable in both microbes and indirect symbiont-symbiont interactions.
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Affiliation(s)
- Eric J Caldera
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Marc G Chevrette
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Bradon R McDonald
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Cameron R Currie
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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13
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González CT, Saltonstall K, Fernández-Marín H. Garden microbiomes of Apterostigma dentigerum and Apterostigma pilosum fungus-growing ants (Hymenoptera: Formicidae). J Microbiol 2019; 57:842-851. [PMID: 31377982 DOI: 10.1007/s12275-019-8639-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 04/08/2019] [Accepted: 05/03/2019] [Indexed: 12/17/2022]
Abstract
Fungus-growing ants share a complex symbiosis with microbes, including fungal mutualists, antibiotic-producing bacteria, and fungal pathogens. The bacterial communities associated with this symbiosis are poorly understood but likely play important roles in maintaining the health and function of fungal gardens. We studied bacterial communities in gardens of two Apterostigma species, A. dentigerum, and A. pilosum, using next-generation sequencing to evaluate differences between the two ant species, their veiled and no-veiled fungal garden types, and across three collection locations. We also compared different parts of nests to test for homogeneity within nests. Enterobacteriaceae dominated gardens of both species and common OTUs were shared across both species and nest types. However, differences in community diversity were detected between ant species, and in the communities of A. dentigerum veiled and no-veiled nests within sites. Apterostigma pilosum had a higher proportion of Phyllobacteriaceae and differed from A. dentigerum in the proportions of members of the order Clostridiales. Within A. dentigerum, nests with veiled and no-veiled fungus gardens had similar taxonomic profiles but differed in the relative abundance of some groups, with veiled gardens having more Rhodospirillaceae and Hyphomicrobiaceae, and no-veiled having more Xanthomonadaceae and certain genera in the Enterobacteriaceae C. However, bacterial communities in Apterostigma fungal gardens are highly conserved and resemble those of the nests of other attine ants with dominant taxa likely playing a role in biomass degradation and defense. Further work is required to understand and explain how bacterial community composition of fungus-growing nests is maintained.
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Affiliation(s)
- Cely T González
- Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, Apartado, 0843-01103, Clayton, Republic of Panama. .,Department of Biotechnology, Acharya Nagarjuna University, Guntur, India. .,Smithsonian Tropical Research Institute, P.O. Box 0843-03092, Amador, Naos, Republic of Panama.
| | - Kristin Saltonstall
- Smithsonian Tropical Research Institute, P.O. Box 0843-03092, Amador, Naos, Republic of Panama
| | - Hermógenes Fernández-Marín
- Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, Apartado, 0843-01103, Clayton, Republic of Panama.
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14
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Abstract
Low-cost, high-throughput nucleic acid sequencing ushered the field of microbial ecology into a new era in which the microbial composition of nearly every conceivable environment on the planet is under examination. However, static "screenshots" derived from sequence-only approaches belie the underlying complexity of the microbe-microbe and microbe-host interactions occurring within these systems. Reductionist experimental models are essential to identify the microbes involved in interactions and to characterize the molecular mechanisms that manifest as complex host and environmental phenomena. Herein, we focus on three models (Bacillus-Streptomyces, Aliivibrio fischeri-Hawaiian bobtail squid, and gnotobiotic mice) at various levels of taxonomic complexity and experimental control used to gain molecular insight into microbe-mediated interactions. We argue that when studying microbial communities, it is crucial to consider the scope of questions that experimental systems are suited to address, especially for researchers beginning new projects. Therefore, we highlight practical applications, limitations, and tradeoffs inherent to each model.
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Affiliation(s)
- Marc G Chevrette
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jennifer R Bratburd
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Cameron R Currie
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Reed M Stubbendieck
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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15
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Montoya QV, Martiarena MJS, Danilo Augusto Polezel, Akazu S, Rodrigues A. More pieces to a huge puzzle: Two new Escovopsis species from fungus gardens of attine ants. MycoKeys 2019:97-118. [PMID: 30814906 PMCID: PMC6389644 DOI: 10.3897/mycokeys.46.30951] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/16/2019] [Indexed: 11/12/2022] Open
Abstract
Escovopsis (Ascomycota: Hypocreales, Hypocreaceae) is the only known parasite of the mutualistic fungi cultivated by fungus-growing ants (Formicidae: Myrmicinae: Attini: Attina, the "attines"). Despite its ecological role, the taxonomy and systematics of Escovopsis have been poorly addressed. Here, based on morphological and phylogenetic analyses with three molecular markers (internal transcribed spacer, large subunit ribosomal RNA and the translation elongation factor 1-alpha), we describe Escovopsisclavatus and E.multiformis as new species isolated from fungus gardens of Apterostigma ant species. Our analysis shows that E.clavatus and E.multiformis belong to the most derived Escovopsis clade, whose main character is the presence of conidiophores with vesicles. Nevertheless, the most outstanding feature of both new species is the presence of a swollen region in the central hypha of the conidiophore named swollen cell, which is absent in all previously described Escovopsis species. The less derived Escovopsis clades lack vesicles and their phylogenetic position within the Hypocreaceae still remains unclear. Considering the high genetic diversity in Escovopsis, the description of these new species adds barely two pieces to a huge taxonomic puzzle; however, this discovery is an important piece for building the systematics of this group of fungi.
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Affiliation(s)
- Quimi Vidaurre Montoya
- Department of Biochemistry and Microbiology, UNESP - São Paulo State University, Rio Claro, SP, Brazil São Paulo State University Rio Claro Brazil
| | - Maria Jesus Sutta Martiarena
- Department of Biochemistry and Microbiology, UNESP - São Paulo State University, Rio Claro, SP, Brazil São Paulo State University Rio Claro Brazil
| | - Danilo Augusto Polezel
- Department of Biochemistry and Microbiology, UNESP - São Paulo State University, Rio Claro, SP, Brazil São Paulo State University Rio Claro Brazil
| | - Sérgio Akazu
- Center for the Studies of Social Insects, UNESP - São Paulo State University, Rio Claro, SP, Brazil São Paulo State University Rio Claro Brazil
| | - Andre Rodrigues
- Department of Biochemistry and Microbiology, UNESP - São Paulo State University, Rio Claro, SP, Brazil São Paulo State University Rio Claro Brazil.,Center for the Studies of Social Insects, UNESP - São Paulo State University, Rio Claro, SP, Brazil São Paulo State University Rio Claro Brazil
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16
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Kellner K, Kardish MR, Seal JN, Linksvayer TA, Mueller UG. Symbiont-Mediated Host-Parasite Dynamics in a Fungus-Gardening Ant. MICROBIAL ECOLOGY 2018; 76:530-543. [PMID: 29285550 DOI: 10.1007/s00248-017-1124-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 12/01/2017] [Indexed: 06/07/2023]
Abstract
Group-living can promote the evolution of adaptive strategies to prevent and control disease. Fungus-gardening ants must cope with two sets of pathogens, those that afflict the ants themselves and those of their symbiotic fungal gardens. While much research has demonstrated the impact of specialized fungal pathogens that infect ant fungus gardens, most of these studies focused on the so-called higher attine ants, which are thought to coevolve diffusely with two clades of leucocoprinaceous fungi. Relatively few studies have addressed disease ecology of lower Attini, which are thought to occasionally recruit (domesticate) novel leucocoprinaceous fungi from free-living populations; coevolution between lower-attine ants and their fungi is therefore likely weaker (or even absent) than in the higher Attini, which generally have many derived modifications. Toward understanding the disease ecology of lower-attine ants, this study (a) describes the diversity in the microfungal genus Escovopsis that naturally infect fungus gardens of the lower-attine ant Mycocepurus smithii and (b) experimentally determines the relative contributions of Escovopsis strain (a possible garden disease), M. smithii ant genotype, and fungal cultivar lineage to disease susceptibility and colony fitness. In controlled in-vivo infection laboratory experiments, we demonstrate that the susceptibility to Escovopsis infection was an outcome of ant-cultivar-Escovopsis interaction, rather than solely due to ant genotype or fungal cultivar lineage. The role of complex ant-cultivar-Escovopsis interactions suggests that switching M. smithii farmers onto novel fungus types might be a strategy to generate novel ant-fungus combinations resistant to most, but perhaps not all, Escovopsis strains circulating in a local population of this and other lower-attine ants.
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Affiliation(s)
- Katrin Kellner
- Section of Integrative Biology, University of Texas at Austin, Austin, TX, 78712, USA.
- Department of Biology, University of Texas at Tyler, Tyler, TX, 75799, USA.
| | - M R Kardish
- Section of Integrative Biology, University of Texas at Austin, Austin, TX, 78712, USA
- Deptartment of Evolution and Ecology, University of California, Davis, CA, 95616, USA
| | - J N Seal
- Section of Integrative Biology, University of Texas at Austin, Austin, TX, 78712, USA
- Department of Biology, University of Texas at Tyler, Tyler, TX, 75799, USA
| | - T A Linksvayer
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - U G Mueller
- Section of Integrative Biology, University of Texas at Austin, Austin, TX, 78712, USA
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17
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Mueller UG, Kardish MR, Ishak HD, Wright AM, Solomon SE, Bruschi SM, Carlson AL, Bacci M. Phylogenetic patterns of ant-fungus associations indicate that farming strategies, not only a superior fungal cultivar, explain the ecological success of leafcutter ants. Mol Ecol 2018; 27:2414-2434. [PMID: 29740906 DOI: 10.1111/mec.14588] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 03/13/2018] [Accepted: 03/14/2018] [Indexed: 01/18/2023]
Abstract
To elucidate fungicultural specializations contributing to ecological dominance of leafcutter ants, we estimate the phylogeny of fungi cultivated by fungus-growing (attine) ants, including fungal cultivars from (i) the entire leafcutter range from southern South America to southern North America, (ii) all higher-attine ant lineages (leafcutting genera Atta, Acromyrmex; nonleafcutting genera Trachymyrmex, Sericomyrmex) and (iii) all lower-attine lineages. Higher-attine fungi form two clades, Clade-A fungi (Leucocoprinus gongylophorus, formerly Attamyces) previously thought to be cultivated only by leafcutter ants, and a sister clade, Clade-B fungi, previously thought to be cultivated only by Trachymyrmex and Sericomyrmex ants. Contradicting this traditional view, we find that (i) leafcutter ants are not specialized to cultivate only Clade-A fungi because some leafcutter species ranging across South America cultivate Clade-B fungi; (ii) Trachymyrmex ants are not specialized to cultivate only Clade-B fungi because some Trachymyrmex species cultivate Clade-A fungi and other Trachymyrmex species cultivate fungi known so far only from lower-attine ants; (iii) in some locations, single higher-attine ant species or closely related cryptic species cultivate both Clade-A and Clade-B fungi; and (iv) ant-fungus co-evolution among higher-attine mutualisms is therefore less specialized than previously thought. Sympatric leafcutter ants can be ecologically dominant when cultivating either Clade-A or Clade-B fungi, sustaining with either cultivar-type huge nests that command large foraging territories; conversely, sympatric Trachymyrmex ants cultivating either Clade-A or Clade-B fungi can be locally abundant without achieving the ecological dominance of leafcutter ants. Ecological dominance of leafcutter ants therefore does not depend primarily on specialized fungiculture of L. gongylophorus (Clade-A), but must derive from ant-fungus synergisms and unique ant adaptations.
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Affiliation(s)
- Ulrich G Mueller
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas
| | - Melissa R Kardish
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas.,Center for Population Biology, University of California, Davis, California
| | - Heather D Ishak
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas.,Department of Medicine, Stanford University, Stanford, California
| | - April M Wright
- Department of Biological Science, Southeastern Louisiana University, Hammond, Louisiana
| | - Scott E Solomon
- Department of Ecology and Evolutionary Biology, Rice University, Houston, Texas.,Department of Entomology, Smithsonian Institution, Washington, District of Columbia
| | - Sofia M Bruschi
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas.,Centro de Estudos de Insetos Sociais, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil
| | - Alexis L Carlson
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas
| | - Maurício Bacci
- Centro de Estudos de Insetos Sociais, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil
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18
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Carlson AL, Ishak HD, Kurian J, Mikheyev AS, Gifford I, Mueller UG. Nuclear populations of the multinucleate fungus of leafcutter ants can be dekaryotized and recombined to manipulate growth of nutritive hyphal nodules harvested by the ants. Mycologia 2018; 109:832-846. [PMID: 29300677 DOI: 10.1080/00275514.2017.1400304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We dekaryotized the multinucleate fungus Leucocoprinus gongylophorus, a symbiotic fungus cultivated vegetatively by leafcutter ants as their food. To track genetic changes resulting from dekaryotization (elimination of some nuclei from the multinuclear population), we developed two multiplex microsatellite fingerprinting panels (15 loci total), then characterized the allele profiles of 129 accessions generated by dekaryotization treatment. Genotype profiles of the 129 accessions confirmed allele loss expected by dekaryotization of the multinucleate fungus. We found no evidence for haploid and single-nucleus strains among the 129 accessions. Microscopy of fluorescently stained dekaryotized accessions revealed great variation in nuclei number between cells of the same vegetative mycelium, with cells containing typically between 3 and 15 nuclei/cell (average = 9.4 nuclei/cell; mode = 8). We distinguish four mycelial morphotypes among the dekaryotized accessions; some of these morphotypes had lost the full competence to produce gongylidia (nutritive hyphal-tip swellings consumed by leafcutter ants as food). In mycelial growth confrontations between different gongylidia-incompetent accessions, allele profiles suggest exchange of nuclei between dekaryotized accessions, restoring full gongylidia competence in some of these strains. The restoration of gongylidia competence after genetic exchange between dekaryotized strains suggests the hypothesis that complementary nuclei interact, or nuclear and cytoplasmic factors interact, to promote or enable gongylidia competence.
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Affiliation(s)
- Alexis L Carlson
- a Department of Integrative Biology , University of Texas at Austin , Austin , Texas 78712
| | - Heather D Ishak
- a Department of Integrative Biology , University of Texas at Austin , Austin , Texas 78712
| | - James Kurian
- a Department of Integrative Biology , University of Texas at Austin , Austin , Texas 78712
| | - Alexander S Mikheyev
- b Okinawa Institute of Science and Technology , 1919-1 Tancha, Onna-son, Kunigami , Okinawa 904-2234 , Japan
| | - Isaac Gifford
- a Department of Integrative Biology , University of Texas at Austin , Austin , Texas 78712
| | - Ulrich G Mueller
- a Department of Integrative Biology , University of Texas at Austin , Austin , Texas 78712
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19
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Hogan CT, Jones TH, Zhukova M, Sosa-Calvo J, Adams RM. Novel mandibular gland volatiles from Apterostigma ants. BIOCHEM SYST ECOL 2017. [DOI: 10.1016/j.bse.2017.04.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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20
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Liu X, Wang L, Xiang M. Chapter 25 Coevolution of Fungi and Invertebrates. Mycology 2017. [DOI: 10.1201/9781315119496-26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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21
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Antimicrobial activities of secondary metabolites and phylogenetic study of sponge endosymbiotic bacteria, Bacillus sp. at Agatti Island, Lakshadweep Archipelago. ACTA ACUST UNITED AC 2016; 11:44-52. [PMID: 28352539 PMCID: PMC5042297 DOI: 10.1016/j.btre.2016.06.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 06/02/2016] [Accepted: 06/06/2016] [Indexed: 11/23/2022]
Abstract
Twenty-one species of sponges were recorded under the class of Demospongiae and Calcareous sponges of which 19 species were new to Agatti reef. A total of 113 Sponge endosymbiotic bacterial strains were isolated from twenty-one species of sponges and screened for antimicrobial activity. Five bacterial strains of sponge endosymbiotic bacteria (SEB) namely SEB32, SEB33, SEB36, SEB43 and SEB51 showed antimicrobial activity against virulent marine fish pathogens such as Vibrio alginolyticus, Vibrio vulnificus, Vibrio parahaemolyticus, Aeromonas salmonicida, Flavobacterium sp., Edwardsiella sp., Proteus mirabilis and Citrobacter brackii. The secondary metabolites produced by SEB32 from sponge Dysidea fragilis (Montagu, 1818) [48] was selected with broad range of antibacterial activity and subjected for production, characterization by series of chromatography techniques and spectroscopic methods. Based on the results of FT-IR and mass spectrometry, the active molecule was tentatively predicted as "Pyrrol" and the structure is Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro- with molecular formula of C7H10N2O2. The LC50 of active molecule was 31 μg/ml and molecular weight of the metabolites was 154. The potential strain SEB32 was identified by gene sequence (GenBank Accession number JX985748) and identified as Bacillus sp. from GenBank database.
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22
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Birnbaum SSL, Gerardo NM. Patterns of Specificity of the Pathogen Escovopsis across the Fungus-Growing Ant Symbiosis. Am Nat 2016; 188:52-65. [PMID: 27322121 DOI: 10.1086/686911] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Parasites evolve within complex abiotic and biotic environments. Because of this, it is often challenging to ascertain how evolutionary and ecological processes together affect parasite specialization. Here, we use the fungus-growing ant system, which consists of ancient, likely coevolved, complex communities, to explore the ecological and evolutionary forces shaping host-parasite specificity. We use a comparative phylogenetic framework to determine whether patterns of specificity between the fungal parasite Escovopsis and its host fungi at fine phylogenetic scales reflect patterns of specificity at broader phylogenetic levels. In other words, we ask whether parasite specificity across broad host phylogenetic relationships is maintained by specificity toward more closely related hosts. We couple this exploration with manipulations of the community context within which host-parasite interactions are taking place to evaluate how community complexity alters parasite specificity. Regardless of host community complexity, parasites displayed a consistent pattern of specialization on native hosts, that is, those that they are found attacking in nature, with the potential for occasional switching to hosts distantly related to their native hosts. These results suggest that, even within a complex community context, pairwise host and parasite adaptation and coadaptation can be the primary drivers of the evolution and maintenance of parasite specificity.
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23
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Mycobiont-photobiont interactions of the lichen Cetraria aculeata in high alpine regions of East Africa and South America. Symbiosis 2015. [DOI: 10.1007/s13199-015-0351-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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24
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Reis BMDS, Silva A, Alvarez MR, Oliveira TBD, Rodrigues A. Fungal communities in gardens of the leafcutter ant Atta cephalotes in forest and cabruca agrosystems of southern Bahia State (Brazil). Fungal Biol 2015; 119:1170-1178. [PMID: 26615740 DOI: 10.1016/j.funbio.2015.09.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 09/03/2015] [Accepted: 09/03/2015] [Indexed: 01/28/2023]
Abstract
Leaf-cutting ants interact with several fungi in addition to the fungal symbiont they cultivate for food. Here, we assessed alien fungal communities in colonies of Atta cephalotes. Fungus garden fragments were sampled from colonies in the Atlantic Rainforest and in a cabruca agrosystem in the state of Bahia (Brazil) in two distinct periods to evaluate whether differences in nest habitat influence the diversity of fungi in the ant colonies. We recovered a total of 403 alien fungi isolates from 628 garden fragments. The prevalent taxa found in these samples were Escovopsis sp. (26 %), Escovopsioides nivea (24 %), and Trichoderma spirale (10.9 %). Fungal diversity was similar between the colonies sampled in both areas suggesting that ants focus on reducing loads of alien fungi in the fungus gardens instead of avoiding specific fungi. However, fungal taxa composition differed between colonies sampled in the two areas and between the sampling periods. These differences are likely explained by the availability of plant substrates available for foraging over habitats and periods. Ordination analysis further supported that sampling period was the main attribute for community structuring but also revealed that additional factors may explain the structuring of fungal communities in colonies of A. cephalotes.
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Affiliation(s)
| | - Aline Silva
- UESC - Santa Cruz State University, Department of Biological Sciences, Ilhéus, BA 45662-900, Brazil
| | - Martín Roberto Alvarez
- UESC - Santa Cruz State University, Department of Biological Sciences, Ilhéus, BA 45662-900, Brazil
| | - Tássio Brito de Oliveira
- UNESP - São Paulo State University, Department of Biochemistry and Microbiology, Rio Claro, SP 13560-900, Brazil
| | - Andre Rodrigues
- UNESP - São Paulo State University, Department of Biochemistry and Microbiology, Rio Claro, SP 13560-900, Brazil; UNESP - São Paulo State University, Center for the Study of Social Insects, Rio Claro, SP 13560-900, Brazil.
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25
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Meirelles LA, Solomon SE, Bacci M, Wright AM, Mueller UG, Rodrigues A. Shared Escovopsis parasites between leaf-cutting and non-leaf-cutting ants in the higher attine fungus-growing ant symbiosis. ROYAL SOCIETY OPEN SCIENCE 2015; 2:150257. [PMID: 26473050 PMCID: PMC4593684 DOI: 10.1098/rsos.150257] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 09/07/2015] [Indexed: 05/31/2023]
Abstract
Fungus-gardening (attine) ants grow fungus for food in protected gardens, which contain beneficial, auxiliary microbes, but also microbes harmful to gardens. Among these potentially pathogenic microorganisms, the most consistently isolated are fungi in the genus Escovopsis, which are thought to co-evolve with ants and their cultivar in a tripartite model. To test clade-to-clade correspondence between Escovopsis and ants in the higher attine symbiosis (including leaf-cutting and non-leaf-cutting ants), we amassed a geographically comprehensive collection of Escovopsis from Mexico to southern Brazil, and reconstructed the corresponding Escovopsis phylogeny. Contrary to previous analyses reporting phylogenetic divergence between Escovopsis from leafcutters and Trachymyrmex ants (non-leafcutter), we found no evidence for such specialization; rather, gardens from leafcutters and non-leafcutters genera can sometimes be infected by closely related strains of Escovopsis, suggesting switches at higher phylogenetic levels than previously reported within the higher attine symbiosis. Analyses identified rare Escovopsis strains that might represent biogeographically restricted endemic species. Phylogenetic patterns correspond to morphological variation of vesicle type (hyphal structures supporting spore-bearing cells), separating Escovopsis with phylogenetically derived cylindrical vesicles from ancestral Escovopsis with globose vesicles. The new phylogenetic insights provide an improved basis for future taxonomic and ecological studies of Escovopsis.
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Affiliation(s)
- Lucas A. Meirelles
- Department of Biochemistry and Microbiology, UNESP—São Paulo State University, Rio Claro, São Paulo, Brazil
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | | | - Mauricio Bacci
- Center for the Study of Social Insects, UNESP—São Paulo State University, Rio Claro, São Paulo, Brazil
| | - April M. Wright
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Ulrich G. Mueller
- Department of Biochemistry and Microbiology, UNESP—São Paulo State University, Rio Claro, São Paulo, Brazil
| | - Andre Rodrigues
- Department of Biochemistry and Microbiology, UNESP—São Paulo State University, Rio Claro, São Paulo, Brazil
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26
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Meirelles LA, Montoya QV, Solomon SE, Rodrigues A. New light on the systematics of fungi associated with attine ant gardens and the description of Escovopsis kreiselii sp. nov. PLoS One 2015; 10:e0112067. [PMID: 25617836 PMCID: PMC4305282 DOI: 10.1371/journal.pone.0112067] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 10/08/2014] [Indexed: 11/18/2022] Open
Abstract
Since the formal description of fungi in the genus Escovopsis in 1990, only a few studies have focused on the systematics of this group. For more than two decades, only two Escovopsis species were described; however, in 2013, three additional Escovopsis species were formally described along with the genus Escovopsioides, both found exclusively in attine ant gardens. During a survey for Escovopsis species in gardens of the lower attine ant Mycetophylax morschi in Brazil, we found four strains belonging to the pink-colored Escovopsis clade. Careful examination of these strains revealed significant morphological differences when compared to previously described species of Escovopsis and Escovopsioides. Based on the type of conidiogenesis (sympodial), as well as morphology of conidiogenous cells (percurrent), non-vesiculated conidiophores, and DNA sequences, we describe the four new strains as a new species, Escovopsis kreiselii sp. nov. Phylogenetic analyses using three nuclear markers (Large subunit RNA; translation elongation factor 1-alpha; and internal transcribed spacer) from the new strains as well as available sequences in public databases confirmed that all known fungi infecting attine ant gardens comprise a monophyletic group within the Hypocreaceae family, with very diverse morphological characteristics. Specifically, Escovopsis kreiselii is likely associated with gardens of lower-attine ants and its pathogenicity remains uncertain.
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Affiliation(s)
- Lucas A. Meirelles
- Department of Biochemistry and Microbiology, UNESP Univ Estadual Paulista, Rio Claro, SP, Brazil
| | - Quimi V. Montoya
- Department of Biochemistry and Microbiology, UNESP Univ Estadual Paulista, Rio Claro, SP, Brazil
| | - Scott E. Solomon
- Department of Biosciences, Rice University, Houston, TX, United States of America
| | - Andre Rodrigues
- Department of Biochemistry and Microbiology, UNESP Univ Estadual Paulista, Rio Claro, SP, Brazil
- * E-mail:
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27
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Masiulionis VE, Cabello MN, Seifert KA, Rodrigues A, Pagnocca FC. Escovopsis trichodermoides sp. nov., isolated from a nest of the lower attine ant Mycocepurus goeldii. Antonie van Leeuwenhoek 2015; 107:731-40. [PMID: 25576160 DOI: 10.1007/s10482-014-0367-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 12/18/2014] [Indexed: 10/24/2022]
Abstract
Currently, five species are formally described in Escovopsis, a specialized mycoparasitic genus of fungus gardens of attine ants (Hymenoptera: Formicidae: tribe Attini). Four species were isolated from leaf-cutting ants in Brazil, including Escovopsis moelleri and Escovopsis microspora from nests of Acromyrmex subterraneus molestans, Escovopsis weberi from a nest of Atta sp. and Escovopsis lentecrescens from a nest of Acromyrmex subterraneus subterraneus. The fifth species, Escovopsis aspergilloides was isolated from a nest of the higher attine ant Trachymyrmex ruthae from Trinidad. Here, we describe a new species, Escovopsis trichodermoides isolated from a fungus garden of the lower attine ant Mycocepurus goeldii, which differs from the five other species by highly branched, trichoderma-like conidiophores lacking swollen vesicles, with reduced conidiogenous cells and distinctive conidia morphology. Phylogenetic analyses based on partial tef1 gene sequences support the distinctiveness of this species. A portion of the internal transcribed spacers of the nuclear rDNA was sequenced to serve as a DNA barcode. Future molecular and morphological studies in this group of fungi will certainly unravel the taxonomic diversity of Escovopsis associated with fungus-growing ants.
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Affiliation(s)
- Virginia E Masiulionis
- Centro de Estudos de Insetos Sociais, Instituto de Biociências, UNESP - Univ Estadual Paulista, Campus de Rio Claro, Rio Claro, SP, 13506-900, Brazil,
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Wallace DEE, Asensio JGV, Tomás AAP. Correlation between virulence and genetic structure of Escovopsis strains from leaf-cutting ant colonies in Costa Rica. MICROBIOLOGY-SGM 2014; 160:1727-1736. [PMID: 24836623 DOI: 10.1099/mic.0.073593-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Leaf-cutting ants (genera Atta and Acromyrmex) cultivate a specialized fungus for food in underground chambers employing cut plant material as substrate. Parasitism occurs in this agricultural system and plays an important role in colony fitness. The microfungi Escovopsis, a specialized mycoparasite of the fungal cultivar, is highly prevalent among colonies. In this study, we tested the antagonistic activity of several Escovopsis strains from different geographical areas in Costa Rica. We employed a combination of laboratory tests to evaluate virulence, including pure culture challenges, toxicity to fungus garden pieces and subcolony bioassays. We also performed a phylogenetic analysis of these strains in order to correlate their virulence with the genetic structure of this population. The bioassays yielded results consistent between each other and showed significant differences in antagonistic activity among the parasites evaluated. However, no significant differences were found when comparing the results of the bioassays according to the source of the ants' fungal cultivar. The phylogenetic analyses were consistent with these results: whilst the fungal cultivar phylogeny showed a single clade with limited molecular variation, the Escovopsis phylogeny yielded several clades with the most virulent isolates grouping in the same well-supported clade. These results indicate that there are Escovopsis strains better suited to establish their antagonistic effect, whilst the genetic homogeneity of the fungal cultivars limits their ability to modulate Escovopsis antagonism. These findings should be taken into consideration when evaluating the potential of Escovopsis isolates as biocontrol agents for this important agricultural pest in the Neotropics.
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Affiliation(s)
- Diego E Elizondo Wallace
- Center for Research in Cell and Molecular Biology, University of Costa Rica, San Pedro de Montes de Oca 11501, San José, Costa Rica
| | - Juan G Vargas Asensio
- Biochemistry Department, Faculty of Medicine, University of Costa Rica, San Pedro de Montes de Oca 11501, San José, Costa Rica
| | - Adrián A Pinto Tomás
- Center for Research in Microscopic Structures, University of Costa Rica, San Pedro de Montes de Oca 11501, San José, Costa Rica.,Biochemistry Department, Faculty of Medicine, University of Costa Rica, San Pedro de Montes de Oca 11501, San José, Costa Rica.,Center for Research in Cell and Molecular Biology, University of Costa Rica, San Pedro de Montes de Oca 11501, San José, Costa Rica
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Augustin JO, Groenewald JZ, Nascimento RJ, Mizubuti ESG, Barreto RW, Elliot SL, Evans HC. Yet more "weeds" in the garden: fungal novelties from nests of leaf-cutting ants. PLoS One 2013; 8:e82265. [PMID: 24376525 PMCID: PMC3869688 DOI: 10.1371/journal.pone.0082265] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 10/25/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Symbiotic relationships modulate the evolution of living organisms in all levels of biological organization. A notable example of symbiosis is that of attine ants (Attini; Formicidae: Hymenoptera) and their fungal cultivars (Lepiotaceae and Pterulaceae; Agaricales: Basidiomycota). In recent years, this mutualism has emerged as a model system for studying coevolution, speciation, and multitrophic interactions. Ubiquitous in this ant-fungal symbiosis is the "weedy" fungus Escovopsis (Hypocreales: Ascomycota), known only as a mycoparasite of attine fungal gardens. Despite interest in its biology, ecology and molecular phylogeny--noting, especially, the high genetic diversity encountered--which has led to a steady flow of publications over the past decade, only two species of Escovopsis have formally been described. METHODS AND RESULTS We sampled from fungal gardens and garden waste (middens) of nests of the leaf-cutting ant genus Acromyrmex in a remnant of subtropical Atlantic rainforest in Minas Gerais, Brazil. In culture, distinct morphotypes of Escovopsis sensu lato were recognized. Using both morphological and molecular analyses, three new species of Escovopsis were identified. These are described and illustrated herein--E. lentecrescens, E. microspora, and E. moelleri--together with a re-description of the genus and the type species, E. weberi. The new genus Escovopsioides is erected for a fourth morphotype. We identify, for the first time, a mechanism for horizontal transmission via middens. CONCLUSIONS The present study makes a start at assigning names and formal descriptions to these specific fungal parasites of attine nests. Based on the results of this exploratory and geographically-restricted survey, we expect there to be many more species of the genus Escovopsis and its relatives associated with nests of both the lower and higher Attini throughout their neotropical range, as suggested in previous studies.
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Affiliation(s)
- Juliana O. Augustin
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Johannes Z. Groenewald
- Centraalbureau voor Schimmelcultures–Fungal Biodiversity Centre, Utrecht, The Netherlands
| | - Robson J. Nascimento
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Eduardo S. G. Mizubuti
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Robert W. Barreto
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Simon L. Elliot
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Harry C. Evans
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
- Centre for Agriculture and Biosciences International, Egham, Surrey, United Kingdom
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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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Fernández-Marín H, Bruner G, Gomez EB, Nash DR, Boomsma JJ, Wcislo WT. Dynamic disease management in Trachymyrmex fungus-growing ants (Attini: Formicidae). Am Nat 2013; 181:571-82. [PMID: 23535621 DOI: 10.1086/669664] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Multipartner mutualisms have potentially complex dynamics, with compensatory responses when one partner is lost or relegated to a minor role. Fungus-growing ants (Attini) are mutualistic associates of basidiomycete fungi and antibiotic-producing actinomycete bacteria; the former are attacked by specialized fungi (Escovopsis) and diverse generalist microbes. Ants deploy biochemical defenses from bacteria and metapleural glands (MGs) and express different behaviors to control contaminants. We studied four Trachymyrmex species that differed in relative abundance of actinomycetes to understand interactions among antimicrobial tactics that are contingent on the nature of infection. MG grooming rate and actinomycete abundance were negatively correlated. The two species with high MG grooming rates or abundant actinomycetes made relatively little use of behavioral defenses. Conversely, the two species with relatively modest biochemical defenses relied heavily on behavior. Trade-offs suggest that related species can evolutionarily diverge to rely on different defense mechanisms against the same threat. Neither bacterial symbionts nor MG secretions thus appear to be essential for mounting defenses against the specialized pathogen Escovopsis, but reduced investment in one of these defense modes tends to increase investment in the other.
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Caldera EJ, Currie CR. The population structure of antibiotic-producing bacterial symbionts of Apterostigma dentigerum ants: impacts of coevolution and multipartite symbiosis. Am Nat 2012; 180:604-17. [PMID: 23070321 DOI: 10.1086/667886] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Fungus-growing ants (Attini) are part of a complex symbiosis with Basidiomycetous fungi, which the ants cultivate for food, Ascomycetous fungal pathogens (Escovopsis), which parasitize cultivars, and Actinobacteria, which produce antibiotic compounds that suppress pathogen growth. Earlier studies that have characterized the association between attine ants and their bacterial symbionts have employed broad phylogenetic approaches, with conclusions ranging from a diffuse coevolved mutualism to no specificity being reported. However, the geographic mosaic theory of coevolution proposes that coevolved interactions likely occur at a level above local populations but within species. Moreover, the scale of population subdivision is likely to impact coevolutionary dynamics. Here, we describe the population structure of bacteria associated with the attine Apterostigma dentigerum across Central America using multilocus sequence typing (MLST) of six housekeeping genes. The majority (90%) of bacteria that were isolated grouped into a single clade within the genus Pseudonocardia. In contrast to studies that have suggested that Pseudonocardia dispersal is high and therefore unconstrained by ant associations, we found highly structured ([Formula: see text]) and dispersal-limited (i.e., significant isolation by distance; [Formula: see text], [Formula: see text]) populations over even a relatively small scale (e.g., within the Panama Canal Zone). Estimates of recombination versus mutation were uncharacteristically low compared with estimates for free-living Actinobacteria (e.g., [Formula: see text] in La Selva, Costa Rica), which suggests that recombination is constrained by association with ant hosts. Furthermore, Pseudonocardia population structure was correlated with that of Escovopsis species ([Formula: see text], [Formula: see text]), supporting the bacteria's role in disease suppression. Overall, the population dynamics of symbiotic Pseudonocardia are more consistent with a specialized mutualistic association than with recently proposed models of low specificity and frequent horizontal acquisition.
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Affiliation(s)
- Eric J Caldera
- Department of Zoology, University of Wisconsin, Madison, Wisconsin 53706, USA.
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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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Rodrigues A, Mueller UG, Ishak HD, Bacci M, Pagnocca FC. Ecology of microfungal communities in gardens of fungus-growing ants (Hymenoptera: Formicidae): a year-long survey of three species of attine ants in Central Texas. FEMS Microbiol Ecol 2011; 78:244-55. [PMID: 21671963 DOI: 10.1111/j.1574-6941.2011.01152.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
We profiled the microfungal communities in gardens of fungus-growing ants to evaluate possible species-specific ant-microfungal associations and to assess the potential dependencies of microfungal diversity on ant foraging behavior. In a 1-year survey, we isolated microfungi from nests of Cyphomyrmex wheeleri, Trachymyrmex septentrionalis and Atta texana in Central Texas. Microfungal prevalence was higher in gardens of C. wheeleri (57%) than in the gardens of T. septentrionalis (46%) and A. texana (35%). Culture-dependent methods coupled with a polyphasic approach of species identification revealed diverse and changing microfungal communities in all the sampling periods. Diversity analyses showed no obvious correlations between the number of observed microfungal species, ant species, or the ants' changing foraging behavior across the seasons. However, both correspondence analysis and 5.8S-rRNA gene unifrac analyses suggested structuring of microfungal communities by ant host. These host-specific differences may reflect in part the three different environments where ants were collected. Most interestingly, the specialized fungal parasite Escovopsis was not isolated from any attine garden in this study near the northernmost limit of the range of attine ants, contrasting with previous studies that indicated a significant incidence of this parasite in ant gardens from Central and South America. The observed differences of microfungal communities in attine gardens suggest that the ants are continuously in contact with a diverse microfungal species assemblage.
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Affiliation(s)
- Andre Rodrigues
- Center for the Study of Social Insects, UNESP - São Paulo State University, Rio Claro, SP, Brazil.
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Cafaro MJ, Poulsen M, Little AEF, Price SL, Gerardo NM, Wong B, Stuart AE, Larget B, Abbot P, Currie CR. Specificity in the symbiotic association between fungus-growing ants and protective Pseudonocardia bacteria. Proc Biol Sci 2011; 278:1814-22. [PMID: 21106596 PMCID: PMC3097832 DOI: 10.1098/rspb.2010.2118] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 11/03/2010] [Indexed: 01/31/2023] Open
Abstract
Fungus-growing ants (tribe Attini) engage in a mutualism with a fungus that serves as the ants' primary food source, but successful fungus cultivation is threatened by microfungal parasites (genus Escovopsis). Actinobacteria (genus Pseudonocardia) associate with most of the phylogenetic diversity of fungus-growing ants; are typically maintained on the cuticle of workers; and infection experiments, bioassay challenges and chemical analyses support a role of Pseudonocardia in defence against Escovopsis through antibiotic production. Here we generate a two-gene phylogeny for Pseudonocardia associated with 124 fungus-growing ant colonies, evaluate patterns of ant-Pseudonocardia specificity and test Pseudonocardia antibiotic activity towards Escovopsis. We show that Pseudonocardia associated with fungus-growing ants are not monophyletic: the ants have acquired free-living strains over the evolutionary history of the association. Nevertheless, our analysis reveals a significant pattern of specificity between clades of Pseudonocardia and groups of related fungus-growing ants. Furthermore, antibiotic assays suggest that despite Escovopsis being generally susceptible to inhibition by diverse Actinobacteria, the ant-derived Pseudonocardia inhibit Escovopsis more strongly than they inhibit other fungi, and are better at inhibiting this pathogen than most environmental Pseudonocardia strains tested. Our findings support a model that many fungus-growing ants maintain specialized Pseudonocardia symbionts that help with garden defence.
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Affiliation(s)
- Matías J. Cafaro
- Department of Bacteriology, University of Wisconsin, Madison, 4325 Microbial Sciences Building, 1550 Linden Drive, Madison, WI 53706, USA
- Department of Biology, University of Puerto Rico—Mayagüez, Call Box 9000, Mayagüez, PR 00681, USA
| | - Michael Poulsen
- Department of Bacteriology, University of Wisconsin, Madison, 4325 Microbial Sciences Building, 1550 Linden Drive, Madison, WI 53706, USA
| | - Ainslie E. F. Little
- Department of Bacteriology, University of Wisconsin, Madison, 4325 Microbial Sciences Building, 1550 Linden Drive, Madison, WI 53706, USA
- Quarles and Brady LLP, 33 East Main Street, Suite 900, Madison, WI 53703, USA
| | - Shauna L. Price
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606, USA
| | - Nicole M. Gerardo
- Department of Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Bess Wong
- Department of Public Health Sciences, University of Toronto, Toronto, Ontario, CanadaM5T 1R4
- Sporometrics Inc., 219 Dufferin Street, Suite 20C, Toronto, Ontario, CanadaM6K 1Y9
| | - Alison E. Stuart
- Calgary Board of Education, 939-45th Strasse, Calgary, AB, CanadaT3C 2B9
| | - Bret Larget
- Department of Statistics, University of Wisconsin, Medical Sciences Center, 1300 University Avenue, Madison, WI 53706, USA
- Department of Botany, University of Wisconsin, 430 Lincoln Drive, Madison, WI 53706, USA
| | - Patrick Abbot
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
| | - Cameron R. Currie
- Department of Bacteriology, University of Wisconsin, Madison, 4325 Microbial Sciences Building, 1550 Linden Drive, Madison, WI 53706, USA
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Poulsen M, Cafaro MJ, Erhardt DP, Little AEF, Gerardo NM, Tebbets B, Klein BS, Currie CR. Variation in Pseudonocardia antibiotic defence helps govern parasite-induced morbidity in Acromyrmex leaf-cutting ants. ENVIRONMENTAL MICROBIOLOGY REPORTS 2010; 2:534-540. [PMID: 22896766 PMCID: PMC3418327 DOI: 10.1111/j.1758-2229.2009.00098.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Host-parasite associations are potentially shaped by evolutionary reciprocal selection dynamics, in which parasites evolve to overcome host defences and hosts are selected to counteract these through the evolution of new defences. This is expected to result in variation in parasite-defence interactions, and the evolution of resistant parasites causing increased virulence. Fungus-growing ants maintain antibiotic-producing Pseudonocardia (Actinobacteria) that aid in protection against specialized parasites of the ants' fungal gardens, and current evidence indicates that both symbionts have been associated with the ants for millions of years. Here we examine the extent of variation in the defensive capabilities of the ant-actinobacterial association against Escovopsis (parasite-defence interactions), and evaluate how variation impacts colonies of fungus-growing ants. We focus on five species of Acromyrmex leaf-cutting ants, crossing 12 strains of Pseudonocardia with 12 strains of Escovopsis in a Petri plate bioassay experiment, and subsequently conduct subcolony infection experiments using resistant and non-resistant parasite strains. Diversity in parasite-defence interactions, including pairings where the parasites are resistant, suggests that chemical variation in the antibiotics produced by different actinobacterial strains are responsible for the observed variation in parasite susceptibility. By evaluating the role this variation plays during infection, we show that infection of ant subcolonies with resistant parasite strains results in significantly higher parasite-induced morbidity with respect to garden biomass loss. Our findings thus further establish the role of Pseudonocardia-derived antibiotics in helping defend the ants' fungus garden from the parasite Escovopsis, and provide evidence that small molecules can play important roles as antibiotics in a natural system.
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Affiliation(s)
- Michael Poulsen
- Departments of Bacteriology, University of Wisconsin, Madison, Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706, USA
| | - Matías J. Cafaro
- Departments of Bacteriology, University of Wisconsin, Madison, Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706, USA
- Department of Biology, University of Puerto Rico – Mayaguez, PO Box 9012, Mayaguez, Puerto Rico 00681
| | - Daniel P. Erhardt
- Departments of Bacteriology, University of Wisconsin, Madison, Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706, USA
| | - Ainslie E. F. Little
- Departments of Bacteriology, University of Wisconsin, Madison, Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706, USA
| | - Nicole M. Gerardo
- Department of Biology, Emory University, O. Wayne Rollins Research Center, 1510 Clifton Road NE, Room 2006, Mail Stop #1940-001-1AC, Atlanta, GA 30322, USA
| | - Brad Tebbets
- Medical Microbiology and Immunology, University of Wisconsin, Madison, Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706, USA
| | - Bruce S. Klein
- Medical Microbiology and Immunology, University of Wisconsin, Madison, Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706, USA
| | - Cameron R. Currie
- Departments of Bacteriology, University of Wisconsin, Madison, Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706, USA
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Dentinger BTM, Lodge DJ, Munkacsi AB, Desjardin DE, McLaughlin DJ. PHYLOGENETIC PLACEMENT OF AN UNUSUAL CORAL MUSHROOM CHALLENGES THE CLASSIC HYPOTHESIS OF STRICT COEVOLUTION IN THEAPTEROSTIGMA PILOSUMGROUP ANT-FUNGUS MUTUALISM. Evolution 2009; 63:2172-8. [DOI: 10.1111/j.1558-5646.2009.00697.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Caldera EJ, Poulsen M, Suen G, Currie CR. Insect symbioses: a case study of past, present, and future fungus-growing ant research. ENVIRONMENTAL ENTOMOLOGY 2009; 38:78-92. [PMID: 19791600 DOI: 10.1603/022.038.0110] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Fungus-growing ants (Attini: Formicidae) engage in an obligate mutualism with fungi they cultivate for food. Although biologists have been fascinated with fungus-growing ants since the resurgence of natural history in the modern era, the early stages of research focused mainly on the foraging behavior of the leaf-cutters (the most derived attine lineage). Indeed, the discovery that the ants actually use leaf fragments to manure a fungus did not come until the 1800s. More recently, three additional microbial symbionts have been described, including specialized microfungal parasites of the ant's fungus garden, antibiotic-producing actinobacteria that help protect the fungus garden from the parasite, and a black yeast that parasitizes the ant-actinobacteria mutualism. The fungus-growing ant symbiosis serves as a particularly useful model system for studying insect-microbe symbioses, because, to date, it contains four well-characterized microbial symbionts, including mutualists and parasites that encompass micro-fungi, macro-fungi, yeasts, and bacteria. Here, we discuss approaches for studying insect-microbe symbioses, using the attine ant-microbial symbiosis as our framework. We draw attention to particular challenges in the field of symbiosis, including the establishment of symbiotic associations and symbiont function. Finally, we discuss future directions in insect-microbe research, with particular focus on applying recent advances in DNA sequencing technologies.
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Affiliation(s)
- Eric J Caldera
- Department of Bacteriology, University of Wisconsin-Madison, 4325 Microbial Sciences Building, 1550 Linden Drive, Madison, WI 53706, USA
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Wang G, Yoon SH, Lefait E. Microbial communities associated with the invasive Hawaiian sponge Mycale armata. ISME JOURNAL 2008; 3:374-7. [PMID: 18987678 DOI: 10.1038/ismej.2008.107] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Microbial symbionts are fundamentally important to their host ecology, but microbial communities of invasive marine species remain largely unexplored. Clone libraries and Denaturing gradient gel electrophoresis analyses revealed diverse microbial phylotypes in the invasive marine sponge Mycale armata. Phylotypes were related to eight phyla: Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Acidobacteria, Chloroflexi, Crenarchaeota and Firmicutes, with predominant alphaproteobacterial sequences (>58%). Three Bacterial Phylotype Groups (BPG1--associated only with sequence from marine sponges; BPG2--associated with sponges and other marine organisms and BPG3--potential new phylotypes) were identified in M. armata. The operational taxonomic units (OTU) of cluster BPG2-B, belonging to Rhodobacteraceae, are dominant sequences of two clone libraries of M. armata, but constitute only a small fraction of sequences from the non-invasive sponge Dysidea sp. Six OTUs from M. armata were potential new phylotypes because of their low sequence identity with their reference sequences. Our results suggest that M. armata harbors both sponge-specific phylotypes and bacterial phylotypes from other marine organisms.
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Affiliation(s)
- Guangyi Wang
- Department of Oceanography, University of Hawaii at Manoa, 1000 Pope Road, Honolulu, HI 96822, USA.
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Rodrigues A, Bacci M, Mueller UG, Ortiz A, Pagnocca FC. Microfungal "weeds" in the leafcutter ant symbiosis. MICROBIAL ECOLOGY 2008; 56:604-14. [PMID: 18369523 DOI: 10.1007/s00248-008-9380-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Revised: 02/12/2008] [Accepted: 02/17/2008] [Indexed: 05/14/2023]
Abstract
Leafcutter ants (Formicidae: tribe Attini) are well-known insects that cultivate basidiomycete fungi (Agaricales: Lepiotaceae) as their principal food. Fungus gardens are monocultures of a single cultivar strain, but they also harbor a diverse assemblage of additional microbes with largely unknown roles in the symbiosis. Cultivar-attacking microfungi in the genus Escovopsis are specialized parasites found only in association with attine gardens. Evolutionary theory predicts that the low genetic diversity in monocultures should render ant gardens susceptible to a wide range of diseases, and additional parasites with roles similar to that of Escovopsis are expected to exist. We profiled the diversity of cultivable microfungi found in 37 nests from ten Acromyrmex species from Southern Brazil and compared this diversity to published surveys. Our study revealed a total of 85 microfungal strains. Fusarium oxysporum and Escovopsis were the predominant species in the surveyed gardens, infecting 40.5% and 27% of the nests, respectively. No specific relationship existed regarding microfungal species and ant-host species, ant substrate preference (dicot versus grass) or nesting habit. Molecular data indicated high genetic diversity among Escovopsis isolates. In contrast to the garden parasite, F. oxysporum strains are not specific parasites of the cultivated fungus because strains isolated from attine gardens have similar counterparts found in the environment. Overall, the survey indicates that saprophytic microfungi are prevalent in South American leafcutter ants. We discuss the antagonistic potential of these microorganisms as "weeds" in the ant-fungus symbiosis.
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Affiliation(s)
- A Rodrigues
- Center for the Study of Social Insects, UNESP-São Paulo State University, Av. 24A, n. 1515-Bela Vista, Rio Claro, São Paulo 13506-900, Brazil.
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Mueller UG, Dash D, Rabeling C, Rodrigues A. COEVOLUTION BETWEEN ATTINE ANTS AND ACTINOMYCETE BACTERIA: A REEVALUATION. Evolution 2008; 62:2894-912. [DOI: 10.1111/j.1558-5646.2008.00501.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Refrégier G, Le Gac M, Jabbour F, Widmer A, Shykoff JA, Yockteng R, Hood ME, Giraud T. Cophylogeny of the anther smut fungi and their caryophyllaceous hosts: prevalence of host shifts and importance of delimiting parasite species for inferring cospeciation. BMC Evol Biol 2008; 8:100. [PMID: 18371215 PMCID: PMC2324105 DOI: 10.1186/1471-2148-8-100] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Accepted: 03/27/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Using phylogenetic approaches, the expectation that parallel cladogenesis should occur between parasites and hosts has been validated in some studies, but most others provided evidence for frequent host shifts. Here we examine the evolutionary history of the association between Microbotryum fungi that cause anther smut disease and their Caryophyllaceous hosts. We investigated the congruence between host and parasite phylogenies, inferred cospeciation events and host shifts, and assessed whether geography or plant ecology could have facilitated the putative host shifts identified. For cophylogeny analyses on microorganisms, parasite strains isolated from different host species are generally considered to represent independent evolutionary lineages, often without checking whether some strains actually belong to the same generalist species. Such an approach may mistake intraspecific nodes for speciation events and thus bias the results of cophylogeny analyses if generalist species are found on closely related hosts. A second aim of this study was therefore to evaluate the impact of species delimitation on the inferences of cospeciation. RESULTS We inferred a multiple gene phylogeny of anther smut strains from 21 host plants from several geographic origins, complementing a previous study on the delimitation of fungal species and their host specificities. We also inferred a multi-gene phylogeny of their host plants, and the two phylogenies were compared. A significant level of cospeciation was found when each host species was considered to harbour a specific parasite strain, i.e. when generalist parasite species were not recognized as such. This approach overestimated the frequency of cocladogenesis because individual parasite species capable of infecting multiple host species (i.e. generalists) were found on closely related hosts. When generalist parasite species were appropriately delimited and only a single representative of each species was retained, cospeciation events were not more frequent than expected under a random distribution, and many host shifts were inferred.Current geographic distributions of host species seemed to be of little relevance for understanding the putative historical host shifts, because most fungal species had overlapping geographic ranges. We did detect some ecological similarities, including shared pollinators and habitat types, between host species that were diseased by closely related anther smut species. Overall, genetic similarity underlying the host-parasite interactions appeared to have the most important influence on specialization and host-shifts: generalist multi-host parasite species were found on closely related plant species, and related species in the Microbotryum phylogeny were associated with members of the same host clade. CONCLUSION We showed here that Microbotryum species have evolved through frequent host shifts to moderately distant hosts, and we show further that accurate delimitation of parasite species is essential for interpreting cophylogeny studies.
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Affiliation(s)
- Guislaine Refrégier
- Ecologie, Systématique et Evolution, Bâtiment 360, Université Paris-Sud, F-91405 Orsay cedex, France ; CNRS F-91405 Orsay cedex, France
| | - Mickaël Le Gac
- Ecologie, Systématique et Evolution, Bâtiment 360, Université Paris-Sud, F-91405 Orsay cedex, France ; CNRS F-91405 Orsay cedex, France
- Department of Zoology, 6270 University Boulevard, Vancouver BC V6T 1Z4, Canada
| | - Florian Jabbour
- Ecologie, Systématique et Evolution, Bâtiment 360, Université Paris-Sud, F-91405 Orsay cedex, France ; CNRS F-91405 Orsay cedex, France
| | - Alex Widmer
- ETH Zurich, Institute of Integrative Biology, Plant Ecological Genetics, Universitätstr. 16, 8092 Zurich, Switzerland
| | - Jacqui A Shykoff
- Ecologie, Systématique et Evolution, Bâtiment 360, Université Paris-Sud, F-91405 Orsay cedex, France ; CNRS F-91405 Orsay cedex, France
| | - Roxana Yockteng
- Ecologie, Systématique et Evolution, Bâtiment 360, Université Paris-Sud, F-91405 Orsay cedex, France ; CNRS F-91405 Orsay cedex, France
- MNHN UMR 5202, Unité Origine, structure et évolution de la biodiversité, Département Systématique et Evolution, 16 rue Buffon CP 39 75005, France
| | - Michael E Hood
- Department of Biology, McGuire Life Sciences Building, Amherst College, Rts 9 & 116, Amherst, MA 01002-5000, USA
| | - Tatiana Giraud
- Ecologie, Systématique et Evolution, Bâtiment 360, Université Paris-Sud, F-91405 Orsay cedex, France ; CNRS F-91405 Orsay cedex, France
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Abstract
Agriculture is a specialized form of symbiosis that is known to have evolved in only four animal groups: humans, bark beetles, termites, and ants. Here, we reconstruct the major evolutionary transitions that produced the five distinct agricultural systems of the fungus-growing ants, the most well studied of the nonhuman agriculturalists. We do so with reference to the first fossil-calibrated, multiple-gene, molecular phylogeny that incorporates the full range of taxonomic diversity within the fungus-growing ant tribe Attini. Our analyses indicate that the original form of ant agriculture, the cultivation of a diverse subset of fungal species in the tribe Leucocoprineae, evolved approximately 50 million years ago in the Neotropics, coincident with the early Eocene climatic optimum. During the past 30 million years, three known ant agricultural systems, each involving a phylogenetically distinct set of derived fungal cultivars, have separately arisen from the original agricultural system. One of these derived systems subsequently gave rise to the fifth known system of agriculture, in which a single fungal species is cultivated by leaf-cutter ants. Leaf-cutter ants evolved remarkably recently ( approximately 8-12 million years ago) to become the dominant herbivores of the New World tropics. Our analyses identify relict, extant attine ant species that occupy phylogenetic positions that are transitional between the agricultural systems. Intensive study of those species holds particular promise for clarifying the sequential accretion of ecological and behavioral characters that produced each of the major ant agricultural systems.
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Schlick-Steiner BC, Steiner FM, Konrad H, Seifert B, Christian E, Moder K, Stauffer C, Crozier RH. Specificity and transmission mosaic of ant nest-wall fungi. Proc Natl Acad Sci U S A 2008; 105:940-3. [PMID: 18195358 PMCID: PMC2242721 DOI: 10.1073/pnas.0708320105] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Indexed: 11/18/2022] Open
Abstract
Mutualism, whereby species interact to their mutual benefit, is extraordinary in a competitive world. To recognize general patterns of origin and maintenance from the plethora of mutualistic associations proves a persisting challenge. The simplest situation is believed to be that of a single mutualist specific to a single host, vertically transmitted from one host generation to the next. We characterized ascomycete fungal associates cultured for nest architecture by the ant subgenera Dendrolasius and Chthonolasius. The ants probably manage their fungal mutualists by protecting them against fungal competitors. The ant subgenera display different ant-to-fungus specificity patterns, one-to-two and many-to-one, and we infer vertical transmission, in the latter case overlaid by horizontal transmission. Possible evolutionary trajectories include a reversal from fungiculture by other Lasius subgenera and inheritance of fungi through life cycle interactions of the ant subgenera. The mosaic indicates how specificity patterns can be shaped by an interplay between host life-cycles and transmission adaptations.
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Affiliation(s)
- Birgit C. Schlick-Steiner
- *School of Marine and Tropical Biology, James Cook University, Townsville, Queensland 4811, Australia
- Institute of Forest Entomology, Forest Pathology and Forest Protection, Department of Forest and Soil Sciences, Boku
- Institute of Zoology, Department of Integrative Biology and Biodiversity Research, Boku, University of Natural Resources and Applied Life Sciences, 1190 Vienna, Austria
| | - Florian M. Steiner
- *School of Marine and Tropical Biology, James Cook University, Townsville, Queensland 4811, Australia
- Institute of Forest Entomology, Forest Pathology and Forest Protection, Department of Forest and Soil Sciences, Boku
- Institute of Zoology, Department of Integrative Biology and Biodiversity Research, Boku, University of Natural Resources and Applied Life Sciences, 1190 Vienna, Austria
| | - Heino Konrad
- Institute of Forest Entomology, Forest Pathology and Forest Protection, Department of Forest and Soil Sciences, Boku
| | - Bernhard Seifert
- State Museum of Natural History Görlitz, PSF300154, 02806 Görlitz, Germany; and
| | - Erhard Christian
- Institute of Zoology, Department of Integrative Biology and Biodiversity Research, Boku, University of Natural Resources and Applied Life Sciences, 1190 Vienna, Austria
| | - Karl Moder
- Institute of Mathematics and Applied Statistics, Department of Spatial, Landscape, and Infrastructure Sciences, Boku, University of Natural Resources and Applied Life Sciences, 1180 Vienna, Austria
| | - Christian Stauffer
- Institute of Forest Entomology, Forest Pathology and Forest Protection, Department of Forest and Soil Sciences, Boku
| | - Ross H. Crozier
- *School of Marine and Tropical Biology, James Cook University, Townsville, Queensland 4811, Australia
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Poulsen M, Erhardt DP, Molinaro DJ, Lin TL, Currie CR. Antagonistic bacterial interactions help shape host-symbiont dynamics within the fungus-growing ant-microbe mutualism. PLoS One 2007; 2:e960. [PMID: 17896000 PMCID: PMC1978530 DOI: 10.1371/journal.pone.0000960] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2007] [Accepted: 09/03/2007] [Indexed: 11/18/2022] Open
Abstract
Conflict within mutually beneficial associations is predicted to destabilize relationships, and theoretical and empirical work exploring this has provided significant insight into the dynamics of cooperative interactions. Within mutualistic associations, the expression and regulation of conflict is likely more complex than in intraspecific cooperative relationship, because of the potential presence of: i) multiple genotypes of microbial species associated with individual hosts, ii) multiple species of symbiotic lineages forming cooperative partner pairings, and iii) additional symbiont lineages. Here we explore complexity of conflict expression within the ancient and coevolved mutualistic association between attine ants, their fungal cultivar, and actinomycetous bacteria (Pseudonocardia). Specifically, we examine conflict between the ants and their Pseudonocardia symbionts maintained to derive antibiotics against parasitic microfungi (Escovopsis) infecting the ants' fungus garden. Symbiont assays pairing isolates of Pseudonocardia spp. associated with fungus-growing ants spanning the phylogenetic diversity of the mutualism revealed that antagonism between strains is common. In contrast, antagonism was substantially less common between more closely related bacteria associated with Acromyrmex leaf-cutting ants. In both experiments, the observed variation in antagonism across pairings was primarily due to the inhibitory capabilities and susceptibility of individual strains, but also the phylogenetic relationships between the ant host of the symbionts, as well as the pair-wise genetic distances between strains. The presence of antagonism throughout the phylogenetic diversity of Pseudonocardia symbionts indicates that these reactions likely have shaped the symbiosis from its origin. Antagonism is expected to prevent novel strains from invading colonies, enforcing single-strain rearing within individual ant colonies. While this may align ant-actinomycete interests in the bipartite association, the presence of single strains of Pseudonocardia within colonies may not be in the best interest of the ants, because increasing the diversity of bacteria, and thereby antibiotic diversity, would help the ant-fungus mutualism deal with the specialized parasites.
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Affiliation(s)
- Michael Poulsen
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA.
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Gerardo NM, Caldera EJ. Labile associations between fungus-growing ant cultivars and their garden pathogens. ISME JOURNAL 2007; 1:373-84. [DOI: 10.1038/ismej.2007.57] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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