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Frank ET, Kesner L, Liberti J, Helleu Q, LeBoeuf AC, Dascalu A, Sponsler DB, Azuma F, Economo EP, Waridel P, Engel P, Schmitt T, Keller L. Targeted treatment of injured nestmates with antimicrobial compounds in an ant society. Nat Commun 2023; 14:8446. [PMID: 38158416 PMCID: PMC10756881 DOI: 10.1038/s41467-023-43885-w] [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: 05/26/2023] [Accepted: 11/20/2023] [Indexed: 01/03/2024] Open
Abstract
Infected wounds pose a major mortality risk in animals. Injuries are common in the ant Megaponera analis, which raids pugnacious prey. Here we show that M. analis can determine when wounds are infected and treat them accordingly. By applying a variety of antimicrobial compounds and proteins secreted from the metapleural gland to infected wounds, workers reduce the mortality of infected individuals by 90%. Chemical analyses showed that wound infection is associated with specific changes in the cuticular hydrocarbon profile, thereby likely allowing nestmates to diagnose the infection state of injured individuals and apply the appropriate antimicrobial treatment. This study demonstrates that M. analis ant societies use antimicrobial compounds produced in the metapleural glands to treat infected wounds and reduce nestmate mortality.
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Affiliation(s)
- Erik T Frank
- Department of Ecology and Evolution, Biophore, University of Lausanne, CH-1015, Lausanne, Switzerland.
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, D-97074, Würzburg, Germany.
| | - Lucie Kesner
- Department of Fundamental Microbiology, Biophore, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Joanito Liberti
- Department of Ecology and Evolution, Biophore, University of Lausanne, CH-1015, Lausanne, Switzerland
- Department of Fundamental Microbiology, Biophore, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Quentin Helleu
- Department of Ecology and Evolution, Biophore, University of Lausanne, CH-1015, Lausanne, Switzerland
- Structure et Instabilité des Génomes, Muséum National d'Histoire Naturelle, CNRS UMR 7196, INSERM U1154, 43 rue Cuvier, F-75005, Paris, France
| | - Adria C LeBoeuf
- Department of Biology, University of Fribourg, CH-1700, Fribourg, Switzerland
| | - Andrei Dascalu
- Department of Ecology and Evolution, Biophore, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Douglas B Sponsler
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, D-97074, Würzburg, Germany
| | - Fumika Azuma
- Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Onna, 904-0495, Japan
| | - Evan P Economo
- Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Onna, 904-0495, Japan
- Radcliffe Institute for Advanced Study, Harvard University, Cambridge, 02138, USA
| | - Patrice Waridel
- Protein Analysis Facility, Génopode, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Philipp Engel
- Department of Fundamental Microbiology, Biophore, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Thomas Schmitt
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, D-97074, Würzburg, Germany
| | - Laurent Keller
- Department of Ecology and Evolution, Biophore, University of Lausanne, CH-1015, Lausanne, Switzerland.
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2
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Diehl JMC, Keller A, Biedermann PHW. Comparing the succession of microbial communities throughout development in field and laboratory nests of the ambrosia beetle Xyleborinus saxesenii. Front Microbiol 2023; 14:1151208. [PMID: 37152720 PMCID: PMC10159272 DOI: 10.3389/fmicb.2023.1151208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 03/31/2023] [Indexed: 05/09/2023] Open
Abstract
Some fungus-farming ambrosia beetles rely on multiple nutritional cultivars (Ascomycota: Ophiostomatales and/or yeasts) that seem to change in relative abundance over time. The succession of these fungi could benefit beetle hosts by optimal consumption of the substrate and extended longevity of the nest. However, abundances of fungal cultivars and other symbionts are poorly known and their culture-independent quantification over development has been studied in only a single species. Here, for the first time, we compared the diversity and succession of both fungal and bacterial communities of fungus gardens in the fruit-tree pinhole borer, Xyleborinus saxesenii, from field and laboratory nests over time. By amplicon sequencing of probed fungus gardens of both nest types at three development phases we showed an extreme reduction of diversity in both bacterial and fungal symbionts in laboratory nests. Furthermore, we observed a general transition from nutritional to non-beneficial fungal symbionts during beetle development. While one known nutritional mutualist, Raffaelea canadensis, was occurring more or less stable over time, the second mutualist R. sulphurea was dominating young nests and decreased in abundance at the expense of other secondary fungi. The quicker the succession proceeded, the slower offspring beetles developed, suggesting a negative role of these secondary symbionts. Finally, we found signs of transgenerational costs of late dispersal for daughters, possibly as early dispersers transmitted and started their own nests with less of the non-beneficial taxa. Future studies should focus on the functional roles of the few bacterial taxa that were present in both field and laboratory nests.
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Affiliation(s)
- Janina M. C. Diehl
- Chair of Forest Entomology and Protection, Institute of Forestry, University of Freiburg, Freiburg im Breisgau, Germany
- Insect-Fungus Interactions Research Group, Department of Animal Ecology and Tropical Biology, University of Würzburg, Würzburg, Germany
- *Correspondence: Janina M. C. Diehl,
| | - Alexander Keller
- Faculty of Biology, Cellular and Organismic Networks, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Peter H. W. Biedermann
- Chair of Forest Entomology and Protection, Institute of Forestry, University of Freiburg, Freiburg im Breisgau, Germany
- Peter H. W. Biedermann,
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3
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Goes AC, Kooij PW, Culot L, Bueno OC, Rodrigues A. Distinct and enhanced hygienic responses of a leaf-cutting ant toward repeated fungi exposures. Ecol Evol 2022; 12:e9112. [PMID: 35866016 PMCID: PMC9288931 DOI: 10.1002/ece3.9112] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 06/06/2022] [Accepted: 06/23/2022] [Indexed: 11/10/2022] Open
Abstract
Leaf‐cutting ants and their fungal crops are a textbook example of a long‐term obligatory mutualism. Many microbes continuously enter their nest containing the fungal cultivars, destabilizing the symbiosis and, in some cases, outcompeting the mutualistic partners. Preferably, the ant workers should distinguish between different microorganisms to respond according to their threat level and recurrence in the colony. To address these assumptions, we investigated how workers of Atta sexdens sanitize their fungal crop toward five different fungi commonly isolated from the fungus gardens: Escovopsis sp., Fusarium oxysporum, Metarhizium anisopliae, Trichoderma spirale, and Syncephalastrum sp. Also, to investigate the plasticity of these responses toward recurrences of these fungi, we exposed the colonies with each fungus three times fourteen days apart. As expected, intensities in sanitization differed according to the fungal species. Ants significantly groom their fungal crop more toward F. oxysporum, M. anisopliae, and Syncephalastrum sp. than toward Escovopsis sp. and T. spirale. Weeding, self‐, and allogrooming were observed in less frequency than fungus grooming in all cases. Moreover, we detected a significant increase in the overall responses after repeated exposures for each fungus, except for Escovopsis sp. Our results indicate that A. sexdens workers are able to distinguish between different fungi and apply distinct responses to remove these from the fungus gardens. Our findings also suggest that successive exposures to the same antagonist increase hygiene, indicating plasticity of ant colonies' defenses to previously encountered pathogens.
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Affiliation(s)
- Aryel C Goes
- Department of General and Applied Biology São Paulo State University (UNESP) Rio Claro Brazil
| | - Pepijn W Kooij
- Department of General and Applied Biology São Paulo State University (UNESP) Rio Claro Brazil
| | - Laurence Culot
- Department of Biodiversity 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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4
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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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5
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Worsley SF, Innocent TM, Holmes NA, Al-Bassam MM, Schiøtt M, Wilkinson B, Murrell JC, Boomsma JJ, Yu DW, Hutchings MI. Competition-based screening helps to secure the evolutionary stability of a defensive microbiome. BMC Biol 2021; 19:205. [PMID: 34526023 PMCID: PMC8444595 DOI: 10.1186/s12915-021-01142-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 09/03/2021] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND The cuticular microbiomes of Acromyrmex leaf-cutting ants pose a conundrum in microbiome biology because they are freely colonisable, and yet the prevalence of the vertically transmitted bacteria Pseudonocardia, which contributes to the control of Escovopsis fungus garden disease, is never compromised by the secondary acquisition of other bacterial strains. Game theory suggests that competition-based screening can allow the selective recruitment of antibiotic-producing bacteria from the environment, by providing abundant resources to foment interference competition between bacterial species and by using Pseudonocardia to bias the outcome of competition in favour of antibiotic producers. RESULTS Here, we use RNA-stable isotope probing (RNA-SIP) to confirm that Acromyrmex ants can maintain a range of microbial symbionts on their cuticle by supplying public resources. We then used RNA sequencing, bioassays, and competition experiments to show that vertically transmitted Pseudonocardia strains produce antibacterials that differentially reduce the growth rates of other microbes, ultimately biassing the bacterial competition to allow the selective establishment of secondary antibiotic-producing strains while excluding non-antibiotic-producing strains that would parasitise the symbiosis. CONCLUSIONS Our findings are consistent with the hypothesis that competition-based screening is a plausible mechanism for maintaining the integrity of the co-adapted mutualism between the leaf-cutting ant farming symbiosis and its defensive microbiome. Our results have broader implications for explaining the stability of other complex symbioses involving horizontal acquisition.
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Affiliation(s)
- Sarah F Worsley
- School of Biological Sciences, Norwich Research Park, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Tabitha M Innocent
- Centre for Social Evolution, Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Neil A Holmes
- School of Biological Sciences, Norwich Research Park, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, Norfolk, NR4 7UH, UK
| | - Mahmoud M Al-Bassam
- School of Biological Sciences, Norwich Research Park, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Morten Schiøtt
- Centre for Social Evolution, Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Barrie Wilkinson
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, Norfolk, NR4 7UH, UK
| | - J Colin Murrell
- School of Environmental Sciences, Norwich Research Park, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Jacobus J Boomsma
- Centre for Social Evolution, Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
| | - Douglas W Yu
- School of Biological Sciences, Norwich Research Park, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK.
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, Yunnan, China.
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, 650223, Yunnan, China.
| | - Matthew I Hutchings
- School of Biological Sciences, Norwich Research Park, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK.
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, Norfolk, NR4 7UH, UK.
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6
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Ammonia Production by Streptomyces Symbionts of Acromyrmex Leaf-Cutting Ants Strongly Inhibits the Fungal Pathogen Escovopsis. Microorganisms 2021; 9:microorganisms9081622. [PMID: 34442700 PMCID: PMC8400888 DOI: 10.3390/microorganisms9081622] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 07/25/2021] [Accepted: 07/26/2021] [Indexed: 11/17/2022] Open
Abstract
Leaf-cutting ants live in mutualistic symbiosis with their garden fungus Leucoagaricus gongylophorus that can be attacked by the specialized pathogenic fungus Escovopsis. Actinomyces symbionts from Acromyrmex leaf-cutting ants contribute to protect L. gongylophorus against pathogens. The symbiont Streptomyces sp. Av25_4 exhibited strong activity against Escovopsis weberi in co-cultivation assays. Experiments physically separating E. weberi and Streptomyces sp. Av25_4 allowing only exchange of volatiles revealed that Streptomyces sp. Av25_4 produces a volatile antifungal. Volatile compounds from Streptomyces sp. Av25_4 were collected by closed loop stripping. Analysis by NMR revealed that Streptomyces sp. Av25_4 overproduces ammonia (up to 8 mM) which completely inhibited the growth of E. weberi due to its strong basic pH. Additionally, other symbionts from different Acromyrmex ants inhibited E. weberi by production of ammonia. The waste of ca. one third of Acomyrmex and Atta leaf-cutting ant colonies was strongly basic due to ammonia (up to ca. 8 mM) suggesting its role in nest hygiene. Not only complex and metabolically costly secondary metabolites, such as polyketides, but simple ammonia released by symbionts of leaf-cutting ants can contribute to control the growth of Escovopsis that is sensitive to ammonia in contrast to the garden fungus L. gongylophorus.
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7
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Burkholderia from Fungus Gardens of Fungus-Growing Ants Produces Antifungals That Inhibit the Specialized Parasite Escovopsis. Appl Environ Microbiol 2021; 87:e0017821. [PMID: 33962985 DOI: 10.1128/aem.00178-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Within animal-associated microbiomes, the functional roles of specific microbial taxa are often uncharacterized. Here, we use the fungus-growing ant system, a model for microbial symbiosis, to determine the potential defensive roles of key bacterial taxa present in the ants' fungus gardens. Fungus gardens serve as an external digestive system for the ants, with mutualistic fungi in the genus Leucoagaricus converting the plant substrate into energy for the ants. The fungus garden is host to specialized parasitic fungi in the genus Escovopsis. Here, we examine the potential role of Burkholderia spp. that occur within ant fungus gardens in inhibiting Escovopsis. We isolated members of the bacterial genera Burkholderia and Paraburkholderia from 50% of the 52 colonies sampled, indicating that members of the family Burkholderiaceae are common inhabitants in the fungus gardens of a diverse range of fungus-growing ant genera. Using antimicrobial inhibition bioassays, we found that 28 out of 32 isolates inhibited at least one Escovopsis strain with a zone of inhibition greater than 1 cm. Genomic assessment of fungus garden-associated Burkholderiaceae indicated that isolates with strong inhibition all belonged to the genus Burkholderia and contained biosynthetic gene clusters that encoded the production of two antifungals: burkholdine1213 and pyrrolnitrin. Organic extracts of cultured isolates confirmed that these compounds are responsible for antifungal activities that inhibit Escovopsis but, at equivalent concentrations, not Leucoagaricus spp. Overall, these new findings, combined with previous evidence, suggest that members of the fungus garden microbiome play an important role in maintaining the health and function of fungus-growing ant colonies. IMPORTANCE Many organisms partner with microbes to defend themselves against parasites and pathogens. Fungus-growing ants must protect Leucoagaricus spp., the fungal mutualist that provides sustenance for the ants, from a specialized fungal parasite, Escovopsis. The ants take multiple approaches, including weeding their fungus gardens to remove Escovopsis spores, as well as harboring Pseudonocardia spp., bacteria that produce antifungals that inhibit Escovopsis. In addition, a genus of bacteria commonly found in fungus gardens, Burkholderia, is known to produce secondary metabolites that inhibit Escovopsis spp. In this study, we isolated Burkholderia spp. from fungus-growing ants, assessed the isolates' ability to inhibit Escovopsis spp., and identified two compounds responsible for inhibition. Our findings suggest that Burkholderia spp. are often found in fungus gardens, adding another possible mechanism within the fungus-growing ant system to suppress the growth of the specialized parasite Escovopsis.
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8
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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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9
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Lash CL, Fordyce JA, Kwit C. Nest substrate, more than ant activity, drives fungal pathogen community dissimilarity in seed-dispersing ant nests. Oecologia 2020; 194:649-657. [PMID: 33159541 DOI: 10.1007/s00442-020-04796-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 10/24/2020] [Indexed: 11/30/2022]
Abstract
Myrmecochory is a widespread mutualism in which plants benefit from seed dispersal services by ants. Ants might also be providing seeds with an additional byproduct benefit via reduced plant pathogen loads in the ant nest environment through their antimicrobial glandular secretions. We investigate this byproduct benefit by identifying fungal communities in ant nests and surrounding environments and quantifying fungal community change (1) through time, (2) between different nest substrates, and (3) as a function of average ant activity levels within nests (based on observed ant activity at nest entrances throughout the summer). We split fungal communities by functional guild to determine seed-dispersing ant-induced changes in the overall fungal community, the animal pathogen fungal community, the plant pathogen fungal community, and the myrmecochore pathogen fungal community. Nest substrate (soil or log) explained much of the variation in fungal community dissimilarity, while substrate occupation (ant nest or control sample) and time had no influence on fungal community composition. Average ant activity had no effect on the community turnover in fungal communities except for the myrmecochore pathogenic fungal community. In this community, higher ant activity throughout the summer resulted in more fluctuation in the pathogenic community in the ant nest. Our results are not consistent with a byproduct benefit framework in myrmecochory, but suggest that nest substrate drives dissimilarity in fungal communities. The influence of nest substrate on fungal communities has important implications for seeds taken into ant nests, as well as ant nest location choice by queens and during nest relocation.
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Affiliation(s)
- Chloe L Lash
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, 37996, USA. .,Natural Sciences Department, University of St. Francis, Joliet, IL, 60435, USA.
| | - James A Fordyce
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Charles Kwit
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, 37996, USA.,Department of Forestry, Wildlife and Fisheries, University of Tennessee, Knoxville, TN, 37996, USA
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10
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Shik JZ, Kooij PW, Donoso DA, Santos JC, Gomez EB, Franco M, Crumière AJJ, Arnan X, Howe J, Wcislo WT, Boomsma JJ. Nutritional niches reveal fundamental domestication trade-offs in fungus-farming ants. Nat Ecol Evol 2020; 5:122-134. [PMID: 33106603 PMCID: PMC7610523 DOI: 10.1038/s41559-020-01314-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 08/25/2020] [Indexed: 02/06/2023]
Abstract
During crop domestication, human farmers traded greater productivity for higher crop vulnerability outside specialized cultivation conditions. We found a similar domestication tradeoff across the major co-evolutionary transitions in farming systems of attine ants. First, the fundamental nutritional niches (FNNs) of cultivars narrowed during ~ 60 million years of naturally selected domestication, and laboratory experiments showed that ant farmers representing subsequent domestication stages strictly regulate protein harvest relative to cultivar FNNs. Second, ants with different farming systems differed in their abilities to harvest the resources that best matched the nutritional needs of their fungal cultivars. This was assessed by quantifying realized nutritional niches (RNNs) from analyses of items collected from the mandibles of laden ant foragers in the field. Third, extensive field collections suggest that among-colony genetic diversity of cultivars in small-scale farms may offer population-wide resilience benefits that species with large-scale farming colonies achieve by more elaborate and demanding cultivation practices of less diverse crops. Our results underscore that naturally selected farming systems have potential to shed light on nutritional tradeoffs that shaped the course of culturally evolved human farming.
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Affiliation(s)
- Jonathan Z Shik
- Section of Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark. .,Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark. .,Smithsonian Tropical Research Institute, Panama City, Republic of Panama.
| | - Pepijn W Kooij
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,Comparative Fungal Biology, Department of Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, London, UK.,Center for the Study of Social Insects, São Paulo State University (UNESP), Rio Claro, Brazil
| | - David A Donoso
- Departamento de Biología, Escuela Politécnica Nacional, Quito, Ecuador.,Centro de Investigación de la Biodiversidad y Cambio Climático, Universidad Tecnológica Indoamérica, Quito, Ecuador
| | - Juan C Santos
- Department of Biological Sciences, St. John's University, New York, NY, USA
| | - Ernesto B Gomez
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
| | - Mariana Franco
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
| | - Antonin J J Crumière
- Section of Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Xavier Arnan
- Centre de Recerca Ecològica i Aplicacions Forestals (CREAF), Cerdanyola del Vallès, Spain.,Department of Biological Sciences, University of Pernambuco, Garanhuns, Brazil
| | - Jack Howe
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,Department of Zoology, University of Oxford, Oxford, UK
| | - William T Wcislo
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
| | - Jacobus J Boomsma
- Section of Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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11
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Batey SFD, Greco C, Hutchings MI, Wilkinson B. Chemical warfare between fungus-growing ants and their pathogens. Curr Opin Chem Biol 2020; 59:172-181. [PMID: 32949983 PMCID: PMC7763482 DOI: 10.1016/j.cbpa.2020.08.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/28/2020] [Accepted: 08/03/2020] [Indexed: 12/19/2022]
Abstract
Fungus-growing attine ants are under constant threat from fungal pathogens such as the specialized mycoparasite Escovopsis, which uses combined physical and chemical attack strategies to prey on the fungal gardens of the ants. In defence, some species assemble protective microbiomes on their exoskeletons that contain antimicrobial-producing Actinobacteria. Underlying this network of mutualistic and antagonistic interactions are an array of chemical signals. Escovopsis weberi produces the shearinine terpene-indole alkaloids, which affect ant behaviour, diketopiperazines to combat defensive bacteria, and other small molecules that inhibit the fungal cultivar. Pseudonocardia and Streptomyces mutualist bacteria produce depsipeptide and polyene macrolide antifungals active against Escovopsis spp. The ant nest metabolome is further complicated by competition between defensive bacteria, which produce antibacterials active against even closely related species. Specialist fungal pathogens attack the nests of fungus-growing ants. Ants form mutualistic relationships with defensive actinomycete bacteria. Specialised metabolites underpin these mutualistic and antagonistic interactions.
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Affiliation(s)
- Sibyl F D Batey
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, United Kingdom
| | - Claudio Greco
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, United Kingdom
| | - Matthew I Hutchings
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, United Kingdom; School of Biological Sciences, University of East Anglia, Norwich, NR4 7TU, United Kingdom.
| | - Barrie Wilkinson
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, United Kingdom.
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12
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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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13
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A Comparison of Isolation Methods for Black Fungi Degrading Aromatic Toxins. Mycopathologia 2019; 184:653-660. [DOI: 10.1007/s11046-019-00382-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 08/28/2019] [Indexed: 12/22/2022]
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14
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Bonadies E, Wcislo WT, Gálvez D, Hughes WOH, Fernández-Marín H. Hygiene Defense Behaviors Used by a Fungus-Growing Ant Depend on the Fungal Pathogen Stages. INSECTS 2019; 10:insects10050130. [PMID: 31060310 PMCID: PMC6572560 DOI: 10.3390/insects10050130] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/09/2019] [Accepted: 04/11/2019] [Indexed: 11/24/2022]
Abstract
Parasites and their hosts use different strategies to overcome the defenses of the other, often resulting in an evolutionary arms race. Limited animal studies have explored the differential responses of hosts when challenged by differential parasite loads and different developmental stages of a parasite. The fungus-growing ant Trachymyrmex sp. 10 employs three different hygienic strategies to control fungal pathogens: Grooming the antibiotic-producing metapleural glands (MGs) and planting or weeding their mutualistic fungal crop. By inoculating Trachymyrmex colonies with different parasite concentrations (Metarhizium) or stages (germinated conidia or ungermianted conidia of Metarhizium and Escovopsis), we tested whether ants modulate and change hygienic strategies depending on the nature of the parasite challenge. There was no effect of the concentration of parasite on the frequencies of the defensive behaviors, indicating that the ants did not change defensive strategy according to the level of threat. However, when challenged with conidia of Escovopsis sp. and Metarhizium brunneum that were germinated or not-germinated, the ants adjusted their thygienic behavior to fungal planting and MG grooming behaviors using strategies depending on the conidia germination status. Our study suggests that fungus-growing ants can adjust the use of hygienic strategies based on the nature of the parasites.
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Affiliation(s)
- Ernesto Bonadies
- Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Apartado 0843-01103, Panamá, República de Panamá.
- Programa de Maestría en Entomología, Vicerrectoría de Investigación y Postgrado, Estafeta Universitaria 0824, Universidad de Panamá, República de Panamá.
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panamá, República de Panamá.
| | - William T Wcislo
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panamá, República de Panamá.
| | - Dumas Gálvez
- Programa de Maestría en Entomología, Vicerrectoría de Investigación y Postgrado, Estafeta Universitaria 0824, Universidad de Panamá, República de Panamá.
| | | | - Hermógenes Fernández-Marín
- Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Apartado 0843-01103, Panamá, República de Panamá.
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15
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16
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Diverse metabolic pathways in the degradation of phenylalkanoic acids and their monohydroxylated derivatives in Cupriavidus sp. strain ST-14. Process Biochem 2018. [DOI: 10.1016/j.procbio.2018.08.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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17
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Nilsson-Møller S, Poulsen M, Innocent TM. A Visual Guide for Studying Behavioral Defenses to Pathogen Attacks in Leaf-Cutting Ants. J Vis Exp 2018. [PMID: 30371666 PMCID: PMC6235524 DOI: 10.3791/58420] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The complex lifestyle, evolutionary history of advanced cooperation, and disease defenses of leaf-cutting ants are well studied. Although numerous studies have described the behaviors connected with disease defense, and the associated use of chemicals and antimicrobials, no common visual reference has been made. The main aim of this study was to record short clips of behaviors involved in disease defense, both prophylactically and directly targeted towards an antagonist of the colony following infection. To do so we used an infection experiment, with sub-colonies of the leaf-cutting ant species Acromyrmex echinatior, and the most significant known pathogenic threat to the ants' fungal crop (Leucoagaricus gongylophorus), a specialized pathogenic fungus in the genus Escovopsis. We filmed and compared infected and uninfected colonies, at both early and more advanced stages of infection. We quantified key defensive behaviors across treatments and show that the behavioral response to pathogen attack likely varies between different castes of worker ants, and between early and late detection of a threat. Based on these recordings we have made a library of behavioral clips, accompanied by definitions of the main individual defensive behaviors. We anticipate that such a guide can provide a common frame of reference for other researchers working in this field, to recognize and study these behaviors, and also provide greater scope for comparing different studies to ultimately help better understand the role these behaviors play in disease defense.
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Affiliation(s)
- Stephen Nilsson-Møller
- Centre for Social Evolution, Section for Ecology and Evolution, Department of Biology, University of Copenhagen
| | - Michael Poulsen
- Centre for Social Evolution, Section for Ecology and Evolution, Department of Biology, University of Copenhagen;
| | - Tabitha M Innocent
- Centre for Social Evolution, Section for Ecology and Evolution, Department of Biology, University of Copenhagen
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18
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Heine D, Holmes NA, Worsley SF, Santos ACA, Innocent TM, Scherlach K, Patrick EH, Yu DW, Murrell JC, Vieria PC, Boomsma JJ, Hertweck C, Hutchings MI, Wilkinson B. Chemical warfare between leafcutter ant symbionts and a co-evolved pathogen. Nat Commun 2018; 9:2208. [PMID: 29880868 PMCID: PMC5992151 DOI: 10.1038/s41467-018-04520-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/24/2018] [Indexed: 11/14/2022] Open
Abstract
Acromyrmex leafcutter ants form a mutually beneficial symbiosis with the fungus Leucoagaricus gongylophorus and with Pseudonocardia bacteria. Both are vertically transmitted and actively maintained by the ants. The fungus garden is manured with freshly cut leaves and provides the sole food for the ant larvae, while Pseudonocardia cultures are reared on the ant-cuticle and make antifungal metabolites to help protect the cultivar against disease. If left unchecked, specialized parasitic Escovopsis fungi can overrun the fungus garden and lead to colony collapse. We report that Escovopsis upregulates the production of two specialized metabolites when it infects the cultivar. These compounds inhibit Pseudonocardia and one, shearinine D, also reduces worker behavioral defenses and is ultimately lethal when it accumulates in ant tissues. Our results are consistent with an active evolutionary arms race between Pseudonocardia and Escovopsis, which modifies both bacterial and behavioral defenses such that colony collapse is unavoidable once Escovopsis infections escalate. Acromyrmex ants cultivate fungus gardens that can be parasitized by Escovopsis sp., leading to colony collapse. Here, Heine et al. identify two secondary metabolites produced by Escovopsis that accumulate in Acromyrmex tissue, reduce behavioural defenses and suppress symbiotic Pseudonocardia bacteria.
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Affiliation(s)
- Daniel Heine
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, Norfolk, NR4 7UH, UK
| | - Neil A Holmes
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK
| | - Sarah F Worsley
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK
| | - Ana Carolina A Santos
- Leibniz Institute for Natural Product Research and Infection Biology, HKI, Beutenbergstraße 11a, Jena, 07745, Germany.,Friedrich Schiller University, Jena, Germany.,Departmento de Química, Universidade Federal de São Carlos, UFSCar, Via Washington Luiz KM 235, CP 676, São Carlos, SP, Brazil
| | - Tabitha M Innocent
- Department of Biology, Centre for Social Evolution, University of Copenhagen, Universitetsparken 15, Copenhagen, 2100, Denmark
| | - Kirstin Scherlach
- Leibniz Institute for Natural Product Research and Infection Biology, HKI, Beutenbergstraße 11a, Jena, 07745, Germany
| | - Elaine H Patrick
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK
| | - Douglas W Yu
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK
| | - J Colin Murrell
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK
| | - Paulo C Vieria
- Departmento de Química, Universidade Federal de São Carlos, UFSCar, Via Washington Luiz KM 235, CP 676, São Carlos, SP, Brazil
| | - Jacobus J Boomsma
- Department of Biology, Centre for Social Evolution, University of Copenhagen, Universitetsparken 15, Copenhagen, 2100, Denmark
| | - Christian Hertweck
- Leibniz Institute for Natural Product Research and Infection Biology, HKI, Beutenbergstraße 11a, Jena, 07745, Germany.,Friedrich Schiller University, Jena, Germany
| | - Matthew I Hutchings
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK.
| | - Barrie Wilkinson
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, Norfolk, NR4 7UH, UK.
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19
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Green PWC, Kooij PW. The role of chemical signalling in maintenance of the fungus garden by leaf-cutting ants. CHEMOECOLOGY 2018. [DOI: 10.1007/s00049-018-0260-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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20
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Pyrazines from bacteria and ants: convergent chemistry within an ecological niche. Sci Rep 2018; 8:2595. [PMID: 29416082 PMCID: PMC5803209 DOI: 10.1038/s41598-018-20953-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 01/26/2018] [Indexed: 02/07/2023] Open
Abstract
Ants use pheromones to coordinate their communal activity. Volatile pyrazines, for instance, mediate food resource gathering and alarm behaviors in different ant species. Here we report that leaf-cutter ant-associated bacteria produce a family of pyrazines that includes members previously identified as ant trail and alarm pheromones. We found that L-threonine induces the bacterial production of the trail pheromone pyrazines, which are common for the host leaf-cutter ants. Isotope feeding experiments revealed that L-threonine along with sodium acetate were the biosynthetic precursors of these natural products and a biosynthetic pathway was proposed.
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21
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Boya P CA, Fernández-Marín H, Mejía LC, Spadafora C, Dorrestein PC, Gutiérrez M. Imaging mass spectrometry and MS/MS molecular networking reveals chemical interactions among cuticular bacteria and pathogenic fungi associated with fungus-growing ants. Sci Rep 2017; 7:5604. [PMID: 28717220 PMCID: PMC5514151 DOI: 10.1038/s41598-017-05515-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/31/2017] [Indexed: 01/25/2023] Open
Abstract
The fungus-growing ant-microbe symbiosis is an ideal system to study chemistry-based microbial interactions due to the wealth of microbial interactions described, and the lack of information on the molecules involved therein. In this study, we employed a combination of MALDI imaging mass spectrometry (MALDI-IMS) and MS/MS molecular networking to study chemistry-based microbial interactions in this system. MALDI IMS was used to visualize the distribution of antimicrobials at the inhibition zone between bacteria associated to the ant Acromyrmex echinatior and the fungal pathogen Escovopsis sp. MS/MS molecular networking was used for the dereplication of compounds found at the inhibition zones. We identified the antibiotics actinomycins D, X2 and X0β, produced by the bacterium Streptomyces CBR38; and the macrolides elaiophylin, efomycin A and efomycin G, produced by the bacterium Streptomyces CBR53.These metabolites were found at the inhibition zones using MALDI IMS and were identified using MS/MS molecular networking. Additionally, three shearinines D, F, and J produced by the fungal pathogen Escovopsis TZ49 were detected. This is the first report of elaiophylins, actinomycin X0β and shearinines in the fungus-growing ant symbiotic system. These results suggest a secondary prophylactic use of these antibiotics by A. echinatior because of their permanent production by the bacteria.
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Affiliation(s)
- Cristopher A Boya P
- Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Panamá, Apartado 0843-01103, Republic of Panama.,Department of Biotechnology, Acharya Nagarjuna University, Guntur, Nagarjuna Nagar, 522 510, India
| | - Hermógenes Fernández-Marín
- Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Panamá, Apartado 0843-01103, Republic of Panama
| | - Luis C Mejía
- Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Panamá, Apartado 0843-01103, Republic of Panama
| | - Carmenza Spadafora
- Centro de Biología Celular y Molecular de Enfermedades, INDICASAT AIP, Panamá, Apartado 0843-01103, Republic of Panama
| | - Pieter C Dorrestein
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, San Diego, California, 92093, United States.,Department of Pharmacology, University of California at San Diego, San Diego, California, 92093, United States
| | - Marcelino Gutiérrez
- Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Panamá, Apartado 0843-01103, Republic of Panama.
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22
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Metabolite analysis of endophytic fungi from cultivars of Zingiber officinale Rosc. identifies myriad of bioactive compounds including tyrosol. 3 Biotech 2017; 7:146. [PMID: 28597159 DOI: 10.1007/s13205-017-0768-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 02/13/2017] [Indexed: 12/30/2022] Open
Abstract
Endophytic fungi associated with rhizomes of four cultivars of Zingiber officinale were identified by molecular and morphological methods and evaluated for their activity against soft rot pathogen Pythium myriotylum and clinical pathogens. The volatile bioactive metabolites produced by these isolates were identified by GC-MS analysis of the fungal crude extracts. Understanding of the metabolites produced by endophytes is also important in the context of raw consumption of ginger as medicine and spice. A total of fifteen isolates were identified from the four varieties studied. The various genera identified were Acremonium sp., Gliocladiopsis sp., Fusarium sp., Colletotrichum sp., Aspergillus sp., Phlebia sp., Earliella sp., and Pseudolagarobasidium sp. The endophytic community was unique to each variety, which could be due to the varying host genotype. Fungi from phylum Basidiomycota were identified for the first time from ginger. Seven isolates showed activity against Pythium, while only two showed antibacterial activity. The bioactive metabolites identified in the fungal crude extracts include tyrosol, benzene acetic acid, ergone, dehydromevalonic lactone, N-aminopyrrolidine, and many bioactive fatty acids and their derivatives which included linoleic acid, oleic acid, myristic acid, n-hexadecanoic acid, palmitic acid methyl ester, and methyl linoleate. The presence of these varying bioactive endophytic fungi may be one of the reasons for the differences in the performance of the different ginger varieties.
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23
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Hu Y, Holway DA, Łukasik P, Chau L, Kay AD, LeBrun EG, Miller KA, Sanders JG, Suarez AV, Russell JA. By their own devices: invasive Argentine ants have shifted diet without clear aid from symbiotic microbes. Mol Ecol 2017; 26:1608-1630. [PMID: 28026894 DOI: 10.1111/mec.13991] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 11/29/2016] [Accepted: 12/01/2016] [Indexed: 12/31/2022]
Abstract
The functions and compositions of symbiotic bacterial communities often correlate with host ecology. Yet cause-effect relationships and the order of symbiont vs. host change remain unclear in the face of ancient symbioses and conserved host ecology. Several groups of ants exemplify this challenge, as their low-nitrogen diets and specialized symbioses appear conserved and ancient. To address whether nitrogen-provisioning symbionts might be important in the early stages of ant trophic shifts, we studied bacteria from the Argentine ant, Linepithema humile - an invasive species that has transitioned towards greater consumption of sugar-rich, nitrogen-poor foods in parts of its introduced range. Bacteria were present at low densities in most L. humile workers, and among those yielding quality 16S rRNA amplicon sequencing data, we found just three symbionts to be common and dominant. Two, a Lactobacillus and an Acetobacteraceae species, were shared between native and introduced populations. The other, a Rickettsia, was found only in two introduced supercolonies. Across an eight-year period of trophic reduction in one introduced population, we found no change in symbionts, arguing against a relationship between natural dietary change and microbiome composition. Overall, our findings thus argue against major changes in symbiotic bacteria in association with the invasion and trophic shift of L. humile. In addition, genome content from close relatives of the identified symbionts suggests that just one can synthesize most essential amino acids; this bacterium was only modestly abundant in introduced populations, providing little support for a major role of nitrogen-provisioning symbioses in Argentine ant's dietary shift.
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Affiliation(s)
- Yi Hu
- Department of Biology, Drexel University, Philadelphia, PA, 19104, USA
| | - David A Holway
- Division of Biological Sciences, University of California-San Diego, La Jolla, CA, 92093, USA
| | - Piotr Łukasik
- Department of Biology, Drexel University, Philadelphia, PA, 19104, USA
| | - Linh Chau
- Department of Biology, Drexel University, Philadelphia, PA, 19104, USA
| | - Adam D Kay
- Department of Biology, University of St. Thomas, St. Paul, MN, 55105, USA
| | - Edward G LeBrun
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX, 78703, USA
| | - Katie A Miller
- Department of Biology, University of St. Thomas, St. Paul, MN, 55105, USA
| | - Jon G Sanders
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Andrew V Suarez
- Department of Animal Biology, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Jacob A Russell
- Department of Biology, Drexel University, Philadelphia, PA, 19104, USA
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24
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Armitage SAO, Fernández-Marín H, Boomsma JJ, Wcislo WT. Slowing them down will make them lose: a role for attine ant crop fungus in defending pupae against infections? J Anim Ecol 2016; 85:1210-21. [PMID: 27136600 PMCID: PMC6084299 DOI: 10.1111/1365-2656.12543] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 04/12/2016] [Indexed: 02/05/2023]
Abstract
Fungus-growing ants (Attini) have evolved an obligate dependency upon a basidiomycete fungus that they cultivate as their food. Less well known is that the crop fungus is also used by many attine species to cover their eggs, larvae and pupae. The adaptive functional significance of this brood covering is poorly understood. One hypothesis to account for this behaviour is that it is part of the pathogen protection portfolio when many thousands of sister workers live in close proximity and larvae and pupae are not protected by cells, as in bees and wasps, and are immobile. We performed behavioural observations on brood covering in the leaf-cutting ant Acromyrmex echinatior, and we experimentally manipulated mycelial cover on pupae and exposed them to the entomopathogenic fungus Metarhizium brunneum to test for a role in pathogen resistance. Our results show that active mycelial brood covering by workers is a behaviourally plastic trait that varies temporally, and across life stages and castes. The presence of a fungal cover on the pupae reduced the rate at which conidia appeared and the percentage of pupal surface that produced pathogen spores, compared to pupae that had fungal cover experimentally removed or naturally had no mycelial cover. Infected pupae with mycelium had higher survival rates than infected pupae without the cover, although this depended upon the time at which adult sister workers were allowed to interact with pupae. Finally, workers employed higher rates of metapleural gland grooming to infected pupae without mycelium than to infected pupae with mycelium. Our results imply that mycelial brood covering may play a significant role in suppressing the growth and subsequent spread of disease, thus adding a novel layer of protection to their defence portfolio.
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Affiliation(s)
- Sophie A O Armitage
- Department of Biology, Centre for Social Evolution, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark
| | - Hermógenes Fernández-Marín
- Department of Biology, Centre for Social Evolution, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark.,Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, Edificio 219, Ciudad del Saber, Clayton, Panamá City, Panamá,Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Panamá
| | - Jacobus J Boomsma
- Department of Biology, Centre for Social Evolution, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark
| | - William T Wcislo
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Panamá
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25
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Tranter C, Fernández‐Marín H, Hughes WOH. Quality and quantity: transitions in antimicrobial gland use for parasite defense. Ecol Evol 2015; 5:5857-68. [PMID: 26811760 PMCID: PMC4717345 DOI: 10.1002/ece3.1827] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 10/09/2015] [Accepted: 10/09/2015] [Indexed: 11/09/2022] Open
Abstract
Parasites are a major force in evolution, and understanding how host life history affects parasite pressure and investment in disease resistance is a general problem in evolutionary biology. The threat of disease may be especially strong in social animals, and ants have evolved the unique metapleural gland (MG), which in many taxa produce antimicrobial compounds that have been argued to have been a key to their ecological success. However, the importance of the MG in the disease resistance of individual ants across ant taxa has not been examined directly. We investigate experimentally the importance of the MG for disease resistance in the fungus-growing ants, a group in which there is interspecific variation in MG size and which has distinct transitions in life history. We find that more derived taxa rely more on the MG for disease resistance than more basal taxa and that there are a series of evolutionary transitions in the quality, quantity, and usage of the MG secretions, which correlate with transitions in life history. These shifts show how even small clades can exhibit substantial transitions in disease resistance investment, demonstrating that host-parasite relationships can be very dynamic and that targeted experimental, as well as large-scale, comparative studies can be valuable for identifying evolutionary transitions.
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Affiliation(s)
| | - Hermógenes Fernández‐Marín
- Instituto de Investigaciones Científicas y Servicios de Alta TecnologíaEdificio 219, Panamá 5Ciudad del SaberClaytonPanama CityPO Box 0843‐01105Republic of Panama
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