1
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AlShamakhi HS, Al-Sadi AM, Cook LG. Phylogenetic Relationships of the Mutualistic Fungi Associated with Macrotermes subhyalinus in Oman. MYCOBIOLOGY 2023; 51:281-287. [PMID: 37929007 PMCID: PMC10621247 DOI: 10.1080/12298093.2023.2258623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 09/11/2023] [Indexed: 11/07/2023]
Abstract
The symbiotic association between fungus-gardening termites Macrotermes and its fungal symbiont has a moderate degree of specificity-although the symbiotic fungi (Termitomyces) form a monophyletic clade, there is not a one-to-one association between termite species and their fungus-garden associates. Here, we aim to determine the origin and phylogenetic relationships of Termitomyces in Oman. We used sequences of the internal transcribed spacer region (ITS) and the nuclear large subunit ribosomal RNA (LSU rRNA, 25S) gene and analyzed these with sequences of Termitomyces from other geographic areas. We find no evidence for more than a single colonization of Oman by Termitomyces. Unexpectedly, we find Termitomyces in Oman is most closely related to the symbiont of M. subhyalinus in West Africa rather than to those of geographically closer populations in East Africa.
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Affiliation(s)
| | - Abdullah M. Al-Sadi
- Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Oman
| | - Lyn G. Cook
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia
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2
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Barrett BT, Kubik TD, Golightly PR, Kellner K, Kardish MR, Mueller UG. Ant genotype, but not genotype of cultivated fungi, predicts queen acceptance in the asexual fungus-farming ant Mycocepurus smithii (Hymenoptera: Formicidae). Behav Ecol Sociobiol 2023. [DOI: 10.1007/s00265-022-03276-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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3
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The Symbiotic Fungus Leucoagaricus gongylophorus (Möller) Singer (Agaricales, Agaricaceae) as a Target Organism to Control Leaf-Cutting Ants. INSECTS 2022; 13:insects13040359. [PMID: 35447801 PMCID: PMC9029082 DOI: 10.3390/insects13040359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 03/19/2022] [Accepted: 04/01/2022] [Indexed: 02/04/2023]
Abstract
Simple Summary The most used approach to control leaf-cutting ants (which cause damage in agricultural areas) is the application of synthetic chemical compounds that directly affect these insects. But another approach is the use of natural substances that attack the symbiotic fungus responsible for many aspects of the survival of the nest. In this study, we discuss the natural substances already reported in the literature to have fungicidal activity and how they could be applicable as products for the control of leaf-cutting ants. Abstract Atta and Acromyrmex are the main genera of leaf-cutting ants present in North and South America, causing extensive damage to agroforestry. Control of the ants requires high handling costs with few effective methods available to decrease the losses. The symbiosis between the leaf-cutting ants and the fungus Leucoagaricus gongylophorus is essential for ant nest survival. Therefore, L. gongylophorus may be a key target in controlling leaf-cutting ants, since its reduction may cause an imbalance in the symbiosis necessary to maintain the nest. Among the options for natural fungal control, plant species are considered important sources of compounds belonging to several classes of natural products that show potential as antifungal agents. This review also presents studies that establish that the antagonist fungi from the Escovopsis and Trichoderma genera effectively reduce the development of L. gongylophorus. The development of nanostructured delivery systems, which have shown advantages over conventional formulations, is suggested for ant control; no commercial nanotechnology-based product has yet been developed, and this appears to be a new approach for future studies.
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4
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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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5
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Matthews AE, Kellner K, Seal JN. Male-biased dispersal in a fungus-gardening ant symbiosis. Ecol Evol 2021; 11:2307-2320. [PMID: 33717457 PMCID: PMC7920773 DOI: 10.1002/ece3.7198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 12/08/2020] [Accepted: 12/11/2020] [Indexed: 02/06/2023] Open
Abstract
For nearly all organisms, dispersal is a fundamental life-history trait that can shape their ecology and evolution. Variation in dispersal capabilities within a species exists and can influence population genetic structure and ecological interactions. In fungus-gardening (attine) ants, co-dispersal of ants and mutualistic fungi is crucial to the success of this obligate symbiosis. Female-biased dispersal (and gene flow) may be favored in attines because virgin queens carry the responsibility of dispersing the fungi, but a paucity of research has made this conclusion difficult. Here, we investigate dispersal of the fungus-gardening ant Trachymyrmex septentrionalis using a combination of maternally (mitochondrial DNA) and biparentally inherited (microsatellites) markers. We found three distinct, spatially isolated mitochondrial DNA haplotypes; two were found in the Florida panhandle and the other in the Florida peninsula. In contrast, biparental markers illustrated significant gene flow across this region and minimal spatial structure. The differential patterns uncovered from mitochondrial DNA and microsatellite markers suggest that most long-distance ant dispersal is male-biased and that females (and concomitantly the fungus) have more limited dispersal capabilities. Consequently, the limited female dispersal is likely an important bottleneck for the fungal symbiont. This bottleneck could slow fungal genetic diversification, which has significant implications for both ant hosts and fungal symbionts regarding population genetics, species distributions, adaptive responses to environmental change, and coevolutionary patterns.
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Affiliation(s)
- Alix E. Matthews
- Department of BiologyThe University of Texas at TylerTylerTXUSA
- Present address:
College of Sciences and Mathematics and Molecular Biosciences ProgramArkansas State UniversityJonesboroARUSA
| | - Katrin Kellner
- Department of BiologyThe University of Texas at TylerTylerTXUSA
| | - Jon N. Seal
- Department of BiologyThe University of Texas at TylerTylerTXUSA
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6
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Amaral KD, Gandra LC, de Souza DJ, Della Lucia TMC. Deleterious action of azadirachtin against the mutualistic fungus of leaf-cutting ants. J Basic Microbiol 2020; 60:931-937. [PMID: 33135277 DOI: 10.1002/jobm.202000541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 10/24/2020] [Indexed: 11/11/2022]
Abstract
Leaf-cutting ants have a beneficial and obligatory relationship with the fungus that they grow. This mutualism allowed the evolutionary success of these ants. The great defoliation capacity of these insects, which often exceeds the level of tolerable economic damage, includes them as severe pests in many cultures. However, given the close relationship between these two agents of mutualism, it is expected that an impact on the fungus will reflect on the performance of the colony as a whole. Therefore, the effect of azadirachtin on the development, and the macronutrient composition of Leucoagaricus gongylophorus was evaluated. Azadirachtin reduced the final fungal mass at the end of treatment at all concentrations tested, but did not reduce the final growth area. A reduction in the amount of hyphae produced with increasing azadirachtin concentration was also observed. Regarding macronutrients, the compound did not affect their total amount in the fungus. Thus, it is observed that azadirachtin did not alter the composition of L. gongylophorus macronutrients, but inhibited its growth by reducing the number of hyphae produced. This reduction reflects directly on the amount of nutrients offered to the workers and the queen and may improve the management of these insects.
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Affiliation(s)
- Karina D Amaral
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Lailla C Gandra
- Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Viçosa, Florestal, Minas Gerais, Brazil
| | - Danival J de Souza
- Programa de Pós-graduação em Produção Vegetal, Universidade Federal do Tocantins, Gurupi, Tocantins, Brazil
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7
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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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8
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High diversity and multiple invasions to North America by fungi grown by the northern-most Trachymyrmex and Mycetomoellerius ant species. FUNGAL ECOL 2020. [DOI: 10.1016/j.funeco.2019.100878] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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9
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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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10
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Patterns of coevolution between ambrosia beetle mycangia and the Ceratocystidaceae, with five new fungal genera and seven new species. Persoonia - Molecular Phylogeny and Evolution of Fungi 2019; 44:41-66. [PMID: 33116335 PMCID: PMC7567963 DOI: 10.3767/persoonia.2020.44.02] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 03/04/2019] [Indexed: 11/30/2022]
Abstract
Ambrosia beetles farm specialised fungi in sapwood tunnels and use pocket-like organs called mycangia to carry propagules of the fungal cultivars. Ambrosia fungi selectively grow in mycangia, which is central to the symbiosis, but the history of coevolution between fungal cultivars and mycangia is poorly understood. The fungal family Ceratocystidaceae previously included three ambrosial genera (Ambrosiella, Meredithiella, and Phialophoropsis), each farmed by one of three distantly related tribes of ambrosia beetles with unique and relatively large mycangium types. Studies on the phylogenetic relationships and evolutionary histories of these three genera were expanded with the previously unstudied ambrosia fungi associated with a fourth mycangium type, that of the tribe Scolytoplatypodini. Using ITS rDNA barcoding and a concatenated dataset of six loci (28S rDNA, 18S rDNA, tef1-α, tub, mcm7, and rpl1), a comprehensive phylogeny of the family Ceratocystidaceae was developed, including Inodoromyces interjectus gen. & sp. nov., a non-ambrosial species that is closely related to the family. Three minor morphological variants of the pronotal disk mycangium of the Scolytoplatypodini were associated with ambrosia fungi in three respective clades of Ceratocystidaceae: Wolfgangiella gen. nov., Toshionella gen. nov., and Ambrosiella remansi sp. nov. Closely-related species that are not symbionts of ambrosia beetles are accommodated by Catunica adiposa gen. & comb. nov. and Solaloca norvegica gen. & comb. nov. The divergent morphology of the ambrosial genera and their phylogenetic placement among non-ambrosial genera suggest three domestication events in the Ceratocystidaceae. Estimated divergence dates for the ambrosia fungi and mycangia suggest that Scolytoplatypodini mycangia may have been the first to acquire Ceratocystidaceae symbionts and other ambrosial fungal genera emerged shortly after the evolution of new mycangium types. There is no evidence of reversion to a non-ambrosial lifestyle in the mycangial symbionts.
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11
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Smith CC, Weber JN, Mikheyev AS, Roces F, Bollazzi M, Kellner K, Seal JN, Mueller UG. Landscape genomics of an obligate mutualism: Concordant and discordant population structures between the leafcutter ant Atta texana and its two main fungal symbiont types. Mol Ecol 2019; 28:2831-2845. [PMID: 31141257 DOI: 10.1111/mec.15111] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 03/10/2019] [Accepted: 03/11/2019] [Indexed: 12/22/2022]
Abstract
To explore landscape genomics at the range limit of an obligate mutualism, we use genotyping-by-sequencing (ddRADseq) to quantify population structure and the effect of host-symbiont interactions between the northernmost fungus-farming leafcutter ant Atta texana and its two main types of cultivated fungus. Genome-wide differentiation between ants associated with either of the two fungal types is of the same order of magnitude as differentiation associated with temperature and precipitation across the ant's entire range, suggesting that specific ant-fungus genome-genome combinations may have been favoured by selection. For the ant hosts, we found a broad cline of genetic structure across the range, and a reduction of genetic diversity along the axis of range expansion towards the range margin. This population-genetic structure was concordant between the ants and one cultivar type (M-fungi, concordant clines) but discordant for the other cultivar type (T-fungi). Discordance in population-genetic structures between ant hosts and a fungal symbiont is surprising because the ant farmers codisperse with their vertically transmitted fungal symbionts. Discordance implies that (a) the fungi disperse also through between-nest horizontal transfer or other unknown mechanisms, and (b) genetic drift and gene flow can differ in magnitude between each partner and between different ant-fungus combinations. Together, these findings imply that variation in the strength of drift and gene flow experienced by each mutualistic partner affects adaptation to environmental stress at the range margin, and genome-genome interactions between host and symbiont influence adaptive genetic differentiation of the host during range evolution in this obligate mutualism.
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Affiliation(s)
- Chad C Smith
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas
| | - Jesse N Weber
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas.,Department of Biological Sciences, University of Alaska, Anchorage, Alaska
| | | | - Flavio Roces
- Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Würzburg, Germany
| | - Martin Bollazzi
- Section of Entomology, Universidad de la República, Montevideo, Uruguay
| | - Katrin Kellner
- Department of Biology, University of Texas at Tyler, Tyler, Texas
| | - Jon N Seal
- Department of Biology, University of Texas at Tyler, Tyler, Texas
| | - Ulrich G Mueller
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas
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12
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Howe J, Schiøtt M, Boomsma JJ. Horizontal partner exchange does not preclude stable mutualism in fungus-growing ants. Behav Ecol 2018. [DOI: 10.1093/beheco/ary176] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Jack Howe
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Morten Schiøtt
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jacobus J Boomsma
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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13
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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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14
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Ant-produced chemicals are not responsible for the specificity of their Ophiocordyceps fungal pathogens. FUNGAL ECOL 2018. [DOI: 10.1016/j.funeco.2017.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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15
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Chomicki G, Renner SS. The interactions of ants with their biotic environment. Proc Biol Sci 2018; 284:rspb.2017.0013. [PMID: 28298352 DOI: 10.1098/rspb.2017.0013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 02/15/2017] [Indexed: 11/12/2022] Open
Abstract
This special feature results from the symposium 'Ants 2016: ant interactions with their biotic environments' held in Munich in May 2016 and deals with the interactions between ants and other insects, plants, microbes and fungi, studied at micro- and macroevolutionary levels with a wide range of approaches, from field ecology to next-generation sequencing, chemical ecology and molecular genetics. In this paper, we review key aspects of these biotic interactions to provide background information for the papers of this special feature After listing the major types of biotic interactions that ants engage in, we present a brief overview of ant/ant communication, ant/plant interactions, ant/fungus symbioses, and recent insights about ants and their endosymbionts. Using a large molecular clock-dated Formicidae phylogeny, we map the evolutionary origins of different ant clades' interactions with plants, fungi and hemiptera. Ants' biotic interactions provide ideal systems to address fundamental ecological and evolutionary questions about mutualism, coevolution, adaptation and animal communication.
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Affiliation(s)
- Guillaume Chomicki
- Systematic Botany and Mycology, University of Munich (LMU), Menzinger Strasse 67, 80638 Munich, Germany
| | - Susanne S Renner
- Systematic Botany and Mycology, University of Munich (LMU), Menzinger Strasse 67, 80638 Munich, Germany
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16
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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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17
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Mueller UG, Ishak HD, Bruschi SM, Smith CC, Herman JJ, Solomon SE, Mikheyev AS, Rabeling C, Scott JJ, Cooper M, Rodrigues A, Ortiz A, Brandão CRF, Lattke JE, Pagnocca FC, Rehner SA, Schultz TR, Vasconcelos HL, Adams RMM, Bollazzi M, Clark RM, Himler AG, LaPolla JS, Leal IR, Johnson RA, Roces F, Sosa-Calvo J, Wirth R, Bacci M. Biogeography of mutualistic fungi cultivated by leafcutter ants. Mol Ecol 2017; 26:6921-6937. [PMID: 29134724 DOI: 10.1111/mec.14431] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/19/2017] [Accepted: 10/04/2017] [Indexed: 01/03/2023]
Abstract
Leafcutter ants propagate co-evolving fungi for food. The nearly 50 species of leafcutter ants (Atta, Acromyrmex) range from Argentina to the United States, with the greatest species diversity in southern South America. We elucidate the biogeography of fungi cultivated by leafcutter ants using DNA sequence and microsatellite-marker analyses of 474 cultivars collected across the leafcutter range. Fungal cultivars belong to two clades (Clade-A and Clade-B). The dominant and widespread Clade-A cultivars form three genotype clusters, with their relative prevalence corresponding to southern South America, northern South America, Central and North America. Admixture between Clade-A populations supports genetic exchange within a single species, Leucocoprinus gongylophorus. Some leafcutter species that cut grass as fungicultural substrate are specialized to cultivate Clade-B fungi, whereas leafcutters preferring dicot plants appear specialized on Clade-A fungi. Cultivar sharing between sympatric leafcutter species occurs frequently such that cultivars of Atta are not distinct from those of Acromyrmex. Leafcutters specialized on Clade-B fungi occur only in South America. Diversity of Clade-A fungi is greatest in South America, but minimal in Central and North America. Maximum cultivar diversity in South America is predicted by the Kusnezov-Fowler hypothesis that leafcutter ants originated in subtropical South America and only dicot-specialized leafcutter ants migrated out of South America, but the cultivar diversity becomes also compatible with a recently proposed hypothesis of a Central American origin by postulating that leafcutter ants acquired novel cultivars many times from other nonleafcutter fungus-growing ants during their migrations from Central America across South America. We evaluate these biogeographic hypotheses in the light of estimated dates for the origins of leafcutter ants and their cultivars.
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Affiliation(s)
- Ulrich G Mueller
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Heather D Ishak
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Sofia M Bruschi
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA.,Centro de Estudos de Insetos Sociais, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil
| | - Chad C Smith
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Jacob J Herman
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Scott E Solomon
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA.,Centro de Estudos de Insetos Sociais, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil.,Department of Ecology & Evolutionary Biology, Rice University, Houston, TX, USA
| | - Alexander S Mikheyev
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA.,Okinawa Institute of Science & Technology, Kunigami, Okinawa, Japan
| | - Christian Rabeling
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA.,School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Jarrod J Scott
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Michael Cooper
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Andre Rodrigues
- Centro de Estudos de Insetos Sociais, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil
| | - Adriana Ortiz
- Universidad Nacional de Colombia, Medellin, Colombia
| | | | - John E Lattke
- Departamento de Zoologia, Universidade Federal do Paraná, Curitiba, Brazil
| | - Fernando C Pagnocca
- Centro de Estudos de Insetos Sociais, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil
| | - Stephen A Rehner
- Mycology and Nematology Genomic Diversity and Biology Laboratory, Beltsville, MD, USA
| | - Ted R Schultz
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | | | - Rachelle M M Adams
- Department of Evolution, Ecology & Organismal Biology, Museum of Biological Diversity, Columbus, OH, USA
| | - Martin Bollazzi
- Section of Entomology, Universidad de la República, Montevideo, Uruguay
| | - Rebecca M Clark
- Integrative Biology, University of California-Berkeley, Berkeley, CA, USA
| | - Anna G Himler
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA.,Department of Biology, College of Idaho, Caldwell, ID, USA
| | - John S LaPolla
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.,Department of Biological Sciences, Towson University, Towson, MD, USA
| | - Inara R Leal
- Departamento de Botânica, Universidade Federal de Pernambuco, Recife, PE, Brazil
| | - Robert A Johnson
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Flavio Roces
- Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Würzburg, Germany
| | | | - Rainer Wirth
- Department of Plant Ecology and Systematics, University of Kaiserslautern, Kaiserslautern, Germany
| | - 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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Branstetter MG, Ješovnik A, Sosa-Calvo J, Lloyd MW, Faircloth BC, Brady SG, Schultz TR. Dry habitats were crucibles of domestication in the evolution of agriculture in ants. Proc Biol Sci 2017; 284:rspb.2017.0095. [PMID: 28404776 PMCID: PMC5394666 DOI: 10.1098/rspb.2017.0095] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/14/2017] [Indexed: 11/12/2022] Open
Abstract
The evolution of ant agriculture, as practised by the fungus-farming 'attine' ants, is thought to have arisen in the wet rainforests of South America about 55-65 Ma. Most subsequent attine agricultural evolution, including the domestication event that produced the ancestor of higher attine cultivars, is likewise hypothesized to have occurred in South American rainforests. The 'out-of-the-rainforest' hypothesis, while generally accepted, has never been tested in a phylogenetic context. It also presents a problem for explaining how fungal domestication might have occurred, given that isolation from free-living populations is required. Here, we use phylogenomic data from ultra-conserved element (UCE) loci to reconstruct the evolutionary history of fungus-farming ants, reduce topological uncertainty, and identify the closest non-fungus-growing ant relative. Using the phylogeny we infer the history of attine agricultural systems, habitat preference and biogeography. Our results show that the out-of-the-rainforest hypothesis is correct with regard to the origin of attine ant agriculture; however, contrary to expectation, we find that the transition from lower to higher agriculture is very likely to have occurred in a seasonally dry habitat, inhospitable to the growth of free-living populations of attine fungal cultivars. We suggest that dry habitats favoured the isolation of attine cultivars over the evolutionary time spans necessary for domestication to occur.
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Affiliation(s)
- Michael G Branstetter
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA .,Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
| | - Ana Ješovnik
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA.,Department of Entomology, University of Maryland, College Park, MD 20742, USA
| | - Jeffrey Sosa-Calvo
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA.,Center for Social Insect Research, School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Michael W Lloyd
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
| | - Brant C Faircloth
- Department of Biological Sciences and Museum of Natural Science, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Seán G Brady
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
| | - Ted R Schultz
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
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19
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Zhao RL, Li GJ, Sánchez-Ramírez S, Stata M, Yang ZL, Wu G, Dai YC, He SH, Cui BK, Zhou JL, Wu F, He MQ, Moncalvo JM, Hyde KD. A six-gene phylogenetic overview of Basidiomycota and allied phyla with estimated divergence times of higher taxa and a phyloproteomics perspective. FUNGAL DIVERS 2017. [DOI: 10.1007/s13225-017-0381-5] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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20
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de Mattos-Shipley K, Ford K, Alberti F, Banks A, Bailey A, Foster G. The good, the bad and the tasty: The many roles of mushrooms. Stud Mycol 2016; 85:125-157. [PMID: 28082758 PMCID: PMC5220184 DOI: 10.1016/j.simyco.2016.11.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Fungi are often inconspicuous in nature and this means it is all too easy to overlook their importance. Often referred to as the "Forgotten Kingdom", fungi are key components of life on this planet. The phylum Basidiomycota, considered to contain the most complex and evolutionarily advanced members of this Kingdom, includes some of the most iconic fungal species such as the gilled mushrooms, puffballs and bracket fungi. Basidiomycetes inhabit a wide range of ecological niches, carrying out vital ecosystem roles, particularly in carbon cycling and as symbiotic partners with a range of other organisms. Specifically in the context of human use, the basidiomycetes are a highly valuable food source and are increasingly medicinally important. In this review, seven main categories, or 'roles', for basidiomycetes have been suggested by the authors: as model species, edible species, toxic species, medicinal basidiomycetes, symbionts, decomposers and pathogens, and two species have been chosen as representatives of each category. Although this is in no way an exhaustive discussion of the importance of basidiomycetes, this review aims to give a broad overview of the importance of these organisms, exploring the various ways they can be exploited to the benefit of human society.
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Affiliation(s)
- K.M.J. de Mattos-Shipley
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - K.L. Ford
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - F. Alberti
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
- School of Life Sciences and Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
| | - A.M. Banks
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
- School of Biology, Devonshire Building, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - A.M. Bailey
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - G.D. Foster
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
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21
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Nygaard S, Hu H, Li C, Schiøtt M, Chen Z, Yang Z, Xie Q, Ma C, Deng Y, Dikow RB, Rabeling C, Nash DR, Wcislo WT, Brady SG, Schultz TR, Zhang G, Boomsma JJ. Reciprocal genomic evolution in the ant-fungus agricultural symbiosis. Nat Commun 2016; 7:12233. [PMID: 27436133 PMCID: PMC4961791 DOI: 10.1038/ncomms12233] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 06/14/2016] [Indexed: 02/02/2023] Open
Abstract
The attine ant-fungus agricultural symbiosis evolved over tens of millions of years, producing complex societies with industrial-scale farming analogous to that of humans. Here we document reciprocal shifts in the genomes and transcriptomes of seven fungus-farming ant species and their fungal cultivars. We show that ant subsistence farming probably originated in the early Tertiary (55-60 MYA), followed by further transitions to the farming of fully domesticated cultivars and leaf-cutting, both arising earlier than previously estimated. Evolutionary modifications in the ants include unprecedented rates of genome-wide structural rearrangement, early loss of arginine biosynthesis and positive selection on chitinase pathways. Modifications of fungal cultivars include loss of a key ligninase domain, changes in chitin synthesis and a reduction in carbohydrate-degrading enzymes as the ants gradually transitioned to functional herbivory. In contrast to human farming, increasing dependence on a single cultivar lineage appears to have been essential to the origin of industrial-scale ant agriculture.
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Affiliation(s)
- Sanne Nygaard
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark
| | - Haofu Hu
- China National Genbank, BGI-Shenzhen, Shenzhen 518083, China
| | - Cai Li
- China National Genbank, BGI-Shenzhen, Shenzhen 518083, China
| | - Morten Schiøtt
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark
| | - Zhensheng Chen
- China National Genbank, BGI-Shenzhen, Shenzhen 518083, China
| | - Zhikai Yang
- China National Genbank, BGI-Shenzhen, Shenzhen 518083, China
| | - Qiaolin Xie
- China National Genbank, BGI-Shenzhen, Shenzhen 518083, China
| | - Chunyu Ma
- China National Genbank, BGI-Shenzhen, Shenzhen 518083, China
| | - Yuan Deng
- China National Genbank, BGI-Shenzhen, Shenzhen 518083, China
| | - Rebecca B. Dikow
- Smithsonian Institute for Biodiversity Genomics, Smithsonian Institution, Washington DC 20013-7012, USA
| | - Christian Rabeling
- Department of Biology, University of Rochester, Rochester, New York 14627, USA
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-7012, USA
| | - David R. Nash
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark
| | - William T. Wcislo
- Smithsonian Tropical Research Institute, Balboa, Ancón 03092, Panama
| | - Seán G. Brady
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-7012, USA
| | - Ted R. Schultz
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-7012, USA
| | - Guojie Zhang
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark
- China National Genbank, BGI-Shenzhen, Shenzhen 518083, China
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Jacobus J. Boomsma
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark
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22
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de Man TJB, Stajich JE, Kubicek CP, Teiling C, Chenthamara K, Atanasova L, Druzhinina IS, Levenkova N, Birnbaum SSL, Barribeau SM, Bozick BA, Suen G, Currie CR, Gerardo NM. Small genome of the fungus Escovopsis weberi, a specialized disease agent of ant agriculture. Proc Natl Acad Sci U S A 2016; 113:3567-72. [PMID: 26976598 PMCID: PMC4822581 DOI: 10.1073/pnas.1518501113] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many microorganisms with specialized lifestyles have reduced genomes. This is best understood in beneficial bacterial symbioses, where partner fidelity facilitates loss of genes necessary for living independently. Specialized microbial pathogens may also exhibit gene loss relative to generalists. Here, we demonstrate that Escovopsis weberi, a fungal parasite of the crops of fungus-growing ants, has a reduced genome in terms of both size and gene content relative to closely related but less specialized fungi. Although primary metabolism genes have been retained, the E. weberi genome is depleted in carbohydrate active enzymes, which is consistent with reliance on a host with these functions. E. weberi has also lost genes considered necessary for sexual reproduction. Contrasting these losses, the genome encodes unique secondary metabolite biosynthesis clusters, some of which include genes that exhibit up-regulated expression during host attack. Thus, the specialized nature of the interaction between Escovopsis and ant agriculture is reflected in the parasite's genome.
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Affiliation(s)
- Tom J B de Man
- Department of Biology, Emory University, Atlanta, GA 30322
| | - Jason E Stajich
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA 92521
| | - Christian P Kubicek
- Institute of Chemical Engineering, Vienna University of Technology, 1060 Vienna, Austria
| | | | - Komal Chenthamara
- Institute of Chemical Engineering, Vienna University of Technology, 1060 Vienna, Austria
| | - Lea Atanasova
- Institute of Chemical Engineering, Vienna University of Technology, 1060 Vienna, Austria
| | - Irina S Druzhinina
- Institute of Chemical Engineering, Vienna University of Technology, 1060 Vienna, Austria
| | | | | | - Seth M Barribeau
- Department of Biology, Emory University, Atlanta, GA 30322; Department of Biology, East Carolina University, Greenville, NC 27858
| | | | - Garret Suen
- Department of Bacteriology, University of Wisconsin, Madison, WI 53706
| | - Cameron R Currie
- Department of Bacteriology, University of Wisconsin, Madison, WI 53706
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23
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Kooij PW, Poulsen M, Schiøtt M, Boomsma JJ. Somatic incompatibility and genetic structure of fungal crops in sympatric Atta colombica and Acromyrmex echinatior leaf-cutting ants. FUNGAL ECOL 2015; 18:10-17. [PMID: 26865859 PMCID: PMC4705864 DOI: 10.1016/j.funeco.2015.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Obligate mutualistic symbioses rely on mechanisms that secure host-symbiont commitments to maximize host benefits and prevent symbiont cheating. Previous studies showed that somatic incompatibilities correlate with neutral-marker-based genetic distances between fungal symbionts of Panamanian Acromyrmex leaf-cutting ants, but the extent to which this relationship applies more generally remained unclear. Here we showed that genetic distances accurately predicted somatic incompatibility for Acromyrmex echinatior symbionts irrespective of whether neutral microsatellites or AFLP markers were used, but that such correlations were weaker or absent in sympatric Atta colombica colonies. Further analysis showed that the symbiont clades maintained by A. echinatior and A. colombica were likely to represent separate gene pools, so that neutral markers were unlikely to be similarly correlated with incompatibility loci that have experienced different selection regimes. We suggest that evolutionarily derived claustral colony founding by Atta queens may have removed selection for strong incompatibility in Atta fungi, as this condition makes the likelihood of symbiont swaps much lower than in Acromyrmex, where incipient nests stay open because queens have to forage until the first workers emerge.
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24
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Kooij PW, Aanen DK, Schiøtt M, Boomsma JJ. Evolutionarily advanced ant farmers rear polyploid fungal crops. J Evol Biol 2015; 28:1911-24. [PMID: 26265100 PMCID: PMC5014177 DOI: 10.1111/jeb.12718] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 07/28/2015] [Indexed: 12/25/2022]
Abstract
Innovative evolutionary developments are often related to gene or genome duplications. The crop fungi of attine fungus-growing ants are suspected to have enhanced genetic variation reminiscent of polyploidy, but this has never been quantified with cytological data and genetic markers. We estimated the number of nuclei per fungal cell for 42 symbionts reared by 14 species of Panamanian fungus-growing ants. This showed that domesticated symbionts of higher attine ants are polykaryotic with 7-17 nuclei per cell, whereas nonspecialized crops of lower attines are dikaryotic similar to most free-living basidiomycete fungi. We then investigated how putative higher genetic diversity is distributed across polykaryotic mycelia, using microsatellite loci and evaluating models assuming that all nuclei are either heterogeneously haploid or homogeneously polyploid. Genetic variation in the polykaryotic symbionts of the basal higher attine genera Trachymyrmex and Sericomyrmex was only slightly enhanced, but the evolutionarily derived crop fungi of Atta and Acromyrmex leaf-cutting ants had much higher genetic variation. Our opposite ploidy models indicated that the symbionts of Trachymyrmex and Sericomyrmex are likely to be lowly and facultatively polyploid (just over two haplotypes on average), whereas Atta and Acromyrmex symbionts are highly and obligatorily polyploid (ca. 5-7 haplotypes on average). This stepwise transition appears analogous to ploidy variation in plants and fungi domesticated by humans and in fungi domesticated by termites and plants, where gene or genome duplications were typically associated with selection for higher productivity, but allopolyploid chimerism was incompatible with sexual reproduction.
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Affiliation(s)
- P W Kooij
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - D K Aanen
- Laboratory of Genetics, Wageningen University, Wageningen, The Netherlands
| | - M Schiøtt
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - J J Boomsma
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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25
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Schultz TR, Sosa-Calvo J, Brady SG, Lopes CT, Mueller UG, Bacci M, Vasconcelos HL. The Most Relictual Fungus-Farming Ant Species Cultivates the Most Recently Evolved and Highly Domesticated Fungal Symbiont Species. Am Nat 2015; 185:693-703. [DOI: 10.1086/680501] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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26
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Andersen SB, Yek SH, Nash DR, Boomsma JJ. Interaction specificity between leaf-cutting ants and vertically transmitted Pseudonocardia bacteria. BMC Evol Biol 2015; 15:27. [PMID: 25886448 PMCID: PMC4346108 DOI: 10.1186/s12862-015-0308-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 02/16/2015] [Indexed: 01/12/2023] Open
Abstract
Background The obligate mutualism between fungus-growing ants and microbial symbionts offers excellent opportunities to study the specificity and stability of multi-species interactions. In addition to cultivating fungus gardens, these ants have domesticated actinomycete bacteria to defend gardens against the fungal parasite Escovopsis and possibly other pathogens. Panamanian Acromyrmex echinatior leaf-cutting ants primarily associate with actinomycetes of the genus Pseudonocardia. Colonies are inoculated with one of two vertically transmitted phylotypes (Ps1 or Ps2), and maintain the same phylotype over their lifetime. We performed a cross-fostering experiment to test whether co-adaptations between ants and bacterial phylotypes have evolved, and how this affects bacterial growth and ant prophylactic behavior after infection with Escovopsis. Results We show that Pseudonocardia readily colonized ants irrespective of their colony of origin, but that the Ps2 phylotype, which was previously shown to be better able to maintain its monocultural integrity after workers became foragers than Ps1, reached a higher final cover when grown on its native host than on alternative hosts. The frequencies of major grooming and weeding behaviors co-varied with symbiont/host combinations, showing that ant behavior also was affected when cuticular actinomycete phylotypes were swapped. Conclusion These results show that the interactions between leaf-cutting ants and Pseudonocardia bear signatures of mutual co-adaptation within a single ant population. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0308-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sandra B Andersen
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark. .,Current address: Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark.
| | - Sze Huei Yek
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark. .,Current address: Department of Genetics, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa.
| | - David R Nash
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark.
| | - Jacobus J Boomsma
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark.
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27
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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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Houadria M, Salas-Lopez A, Orivel J, Blüthgen N, Menzel F. Dietary and Temporal Niche Differentiation in Tropical Ants-Can They Explain Local Ant Coexistence? Biotropica 2014. [DOI: 10.1111/btp.12184] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Mickal Houadria
- Department of Evolutionary Biology; Institute of Zoology; University of Mainz; Mainz Germany
| | | | - Jérôme Orivel
- CNRS; UMR Ecologie de Forêts de Guyane (EcoFoG); Kourou France
| | - Nico Blüthgen
- Department of Biology; Technical University of Darmstadt; Darmstadt Germany
| | - Florian Menzel
- Department of Evolutionary Biology; Institute of Zoology; University of Mainz; Mainz Germany
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De Fine Licht HH, Boomsma JJ. Variable interaction specificity and symbiont performance in Panamanian Trachymyrmex and Sericomyrmex fungus-growing ants. BMC Evol Biol 2014; 14:244. [PMID: 25471204 PMCID: PMC4262973 DOI: 10.1186/s12862-014-0244-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 11/14/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cooperative benefits of mutualistic interactions are affected by genetic variation among the interacting partners, which may have consequences for interaction-specificities across guilds of sympatric species with similar mutualistic life histories. The gardens of fungus-growing (attine) ants produce carbohydrate active enzymes that degrade plant material collected by the ants and offer them food in exchange. The spectrum of these enzyme activities is an important symbiont service to the host but may vary among cultivar genotypes. The sympatric occurrence of several Trachymyrmex and Sericomyrmex higher attine ants in Gamboa, Panama provided the opportunity to do a quantitative study of species-level interaction-specificity. RESULTS We genotyped the ants for Cytochrome Oxidase and their Leucoagaricus fungal cultivars for ITS rDNA. Combined with activity measurements for 12 carbohydrate active enzymes, these data allowed us to test whether garden enzyme activity was affected by fungal strain, farming ants or combinations of the two. We detected two cryptic ant species, raising ant species number from four to six, and we show that the 38 sampled colonies reared a total of seven fungal haplotypes that were different enough to represent separate Leucoagaricus species. The Sericomyrmex species and one of the Trachymyrmex species reared the same fungal cultivar in all sampled colonies, but the remaining four Trachymyrmex species largely shared the other cultivars. Fungal enzyme activity spectra were significantly affected by both cultivar species and farming ant species, and more so for certain ant-cultivar combinations than others. However, relative changes in activity of single enzymes only depended on cultivar genotype and not on the ant species farming a cultivar. CONCLUSIONS Ant cultivar symbiont-specificity varied from almost full symbiont sharing to one-to-one specialization, suggesting that trade-offs between enzyme activity spectra and life-history traits such as desiccation tolerance, disease susceptibility and temperature sensitivity may apply in some combinations but not in others. We hypothesize that this may be related to ecological specialization in general, but this awaits further testing. Our finding of both cryptic ant species and extensive cultivar diversity underlines the importance of identifying all species-level variation before embarking on estimates of interaction specificity.
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Affiliation(s)
- Henrik H De Fine Licht
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark.
- Present address: Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg, Denmark.
| | - Jacobus J Boomsma
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark.
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De Fine Licht HH, Boomsma JJ, Tunlid A. Symbiotic adaptations in the fungal cultivar of leaf-cutting ants. Nat Commun 2014; 5:5675. [DOI: 10.1038/ncomms6675] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 10/24/2014] [Indexed: 11/09/2022] Open
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Masiulionis VE, Rabeling C, De Fine Licht HH, Schultz T, Bacci M, Bezerra CMS, Pagnocca FC. A Brazilian population of the asexual fungus-growing ant Mycocepurus smithii (Formicidae, Myrmicinae, Attini) cultivates fungal symbionts with gongylidia-like structures. PLoS One 2014; 9:e103800. [PMID: 25101899 PMCID: PMC4125159 DOI: 10.1371/journal.pone.0103800] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 07/07/2014] [Indexed: 01/23/2023] Open
Abstract
Attine ants cultivate fungi as their most important food source and in turn the fungus is nourished, protected against harmful microorganisms, and dispersed by the ants. This symbiosis evolved approximately 50-60 million years ago in the late Paleocene or early Eocene, and since its origin attine ants have acquired a variety of fungal mutualists in the Leucocoprineae and the distantly related Pterulaceae. The most specialized symbiotic interaction is referred to as "higher agriculture" and includes leafcutter ant agriculture in which the ants cultivate the single species Leucoagaricus gongylophorus. Higher agriculture fungal cultivars are characterized by specialized hyphal tip swellings, so-called gongylidia, which are considered a unique, derived morphological adaptation of higher attine fungi thought to be absent in lower attine fungi. Rare reports of gongylidia-like structures in fungus gardens of lower attines exist, but it was never tested whether these represent rare switches of lower attines to L. gonglyphorus cultivars or whether lower attine cultivars occasionally produce gongylidia. Here we describe the occurrence of gongylidia-like structures in fungus gardens of the asexual lower attine ant Mycocepurus smithii. To test whether M. smithii cultivates leafcutter ant fungi or whether lower attine cultivars produce gongylidia, we identified the M. smithii fungus utilizing molecular and morphological methods. Results shows that the gongylidia-like structures of M. smithii gardens are morphologically similar to gongylidia of higher attine fungus gardens and can only be distinguished by their slightly smaller size. A molecular phylogenetic analysis of the fungal ITS sequence indicates that the gongylidia-bearing M. smithii cultivar belongs to the so-called "Clade 1"of lower Attini cultivars. Given that M. smithii is capable of cultivating a morphologically and genetically diverse array of fungal symbionts, we discuss whether asexuality of the ant host maybe correlated with low partner fidelity and active symbiont choice between fungus and ant mutualists.
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Affiliation(s)
| | - Christian Rabeling
- Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, United States of America
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, D.C., United States of America
| | - Henrik H. De Fine Licht
- Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ted Schultz
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, D.C., United States of America
| | - Maurício Bacci
- Instituto de Biociências, São Paulo State University, Rio Claro, SP, Brazil
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Shik JZ, Santos JC, Seal JN, Kay A, Mueller UG, Kaspari M. Metabolism and the rise of fungus cultivation by ants. Am Nat 2014; 184:364-73. [PMID: 25141145 DOI: 10.1086/677296] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Most ant colonies are comprised of workers that cooperate to harvest resources and feed developing larvae. Around 50 million years ago (MYA), ants of the attine lineage adopted an alternative strategy, harvesting resources used as compost to produce fungal gardens. While fungus cultivation is considered a major breakthrough in ant evolution, the associated ecological consequences remain poorly understood. Here, we compare the energetics of attine colony-farms and ancestral hunter-gatherer colonies using metabolic scaling principles within a phylogenetic context. We find two major energetic transitions. First, the earliest lower-attine farmers transitioned to lower mass-specific metabolic rates while shifting significant fractions of biomass from ant tissue to fungus gardens. Second, a transition 20 MYA to specialized cultivars in the higher-attine clade was associated with increased colony metabolism (without changes in garden fungal content) and with metabolic scaling nearly identical to hypometry observed in hunter-gatherer ants, although only the hunter-gatherer slope was distinguishable from isometry. Based on these evolutionary transitions, we propose that shifting living-tissue storage from ants to fungal mutualists provided energetic storage advantages contributing to attine diversification and outline critical assumptions that, when tested, will help link metabolism, farming efficiency, and colony fitness.
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Affiliation(s)
- Jonathan Z Shik
- Smithsonian Tropical Research Institute, Balboa, Ancon, Republic of Panama
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Seal JN, Schiøtt M, Mueller UG. Ant-fungus species combinations engineer physiological activity of fungus gardens. ACTA ACUST UNITED AC 2014; 217:2540-7. [PMID: 24803469 DOI: 10.1242/jeb.098483] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Fungus-gardening insects are among the most complex organisms because of their extensive co-evolutionary histories with obligate fungal symbionts and other microbes. Some fungus-gardening insect lineages share fungal symbionts with other members of their lineage and thus exhibit diffuse co-evolutionary relationships, while others exhibit little or no symbiont sharing, resulting in host-fungus fidelity. The mechanisms that maintain this symbiont fidelity are currently unknown. Prior work suggested that derived leaf-cutting ants in the genus Atta interact synergistically with leaf-cutter fungi (Attamyces) by exhibiting higher fungal growth rates and enzymatic activities than when growing a fungus from the sister-clade to Attamyces (so-called 'Trachymyces'), grown primarily by the non-leaf cutting Trachymyrmex ants that form, correspondingly, the sister-clade to leaf-cutting ants. To elucidate the enzymatic bases of host-fungus specialization in leaf-cutting ants, we conducted a reciprocal fungus-switch experiment between the ant Atta texana and the ant Trachymyrmex arizonensis and report measured enzymatic activities of switched and sham-switched fungus gardens to digest starch, pectin, xylan, cellulose and casein. Gardens exhibited higher amylase and pectinase activities when A. texana ants cultivated Attamyces compared with Trachymyces fungi, consistent with enzymatic specialization. In contrast, gardens showed comparable amylase and pectinase activities when T. arizonensis cultivated either fungal species. Although gardens of leaf-cutting ants are not known to be significant metabolizers of cellulose, T. arizonensis were able to maintain gardens with significant cellulase activity when growing either fungal species. In contrast to carbohydrate metabolism, protease activity was significantly higher in Attamyces than in Trachymyces, regardless of the ant host. Activity of some enzymes employed by this symbiosis therefore arises from complex interactions between the ant host and the fungal symbiont.
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Affiliation(s)
- J N Seal
- Department of Biology, University of Texas at Tyler, 3900 University Blvd, Tyler, TX 75799, USA Integrative Biology, University of Texas at Austin, 1 University Station C0930, Austin, TX 78712, USA
| | - M Schiøtt
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark
| | - U G Mueller
- Integrative Biology, University of Texas at Austin, 1 University Station C0930, Austin, TX 78712, USA
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Differences in forage-acquisition and fungal enzyme activity contribute to niche segregation in Panamanian leaf-cutting ants. PLoS One 2014; 9:e94284. [PMID: 24718261 PMCID: PMC3981799 DOI: 10.1371/journal.pone.0094284] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 03/12/2014] [Indexed: 11/19/2022] Open
Abstract
The genera Atta and Acromyrmex are often grouped as leaf-cutting ants for pest management assessments and ecological surveys, although their mature colony sizes and foraging niches may differ substantially. Few studies have addressed such interspecific differences at the same site, which prompted us to conduct a comparative study across six sympatric leaf-cutting ant species in Central Panama. We show that foraging rates during the transition between dry and wet season differ about 60 fold between genera, but are relatively constant across species within genera. These differences appear to match overall differences in colony size, especially when Atta workers that return to their nests without leaves are assumed to carry liquid food. We confirm that Panamanian Atta specialize primarily on tree-leaves whereas Acromyrmex focus on collecting flowers and herbal leaves and that species within genera are similar in these overall foraging strategies. Species within genera tended to be spaced out over the three habitat categories that we distinguished (forest, forest edge, open grassland), but each of these habitats normally had only a single predominant Atta and Acromyrmex species. We measured activities of twelve fungus garden decomposition enzymes, belonging to the amylases, cellulases, hemicellulases, pectinases and proteinases, and show that average enzyme activity per unit of fungal mass in Atta gardens is lower than in Acromyrmex gardens. Expression profiles of fungal enzymes in Atta also appeared to be more specialized than in Acromyrmex, possibly reflecting variation in forage material. Our results suggest that species- and genus-level identities of leaf-cutting ants and habitat-specific foraging profiles may give predictable differences in the expression of fungal genes coding for decomposition enzymes.
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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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Jesovnik A, Sosa-Calvo J, Lopes CT, Vasconcelos HL, Schultz TR. Nest architecture, fungus gardens, queen, males and larvae of the fungus-growing ant Mycetagroicus inflatus Brandão & Mayhé-Nunes. INSECTES SOCIAUX 2013; 60:531-542. [PMID: 24273337 PMCID: PMC3824567 DOI: 10.1007/s00040-013-0320-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 08/28/2013] [Accepted: 08/29/2013] [Indexed: 06/02/2023]
Abstract
All known fungus-growing ants (tribe Attini) are obligately symbiotic with their cultivated fungi. The fungal cultivars of "lower" attine ants are facultative symbionts, capable of living apart from ants, whereas the fungal cultivars of "higher" attine ants, including leaf-cutting genera Atta and Acromyrmex, are highly specialized, obligate symbionts. Since higher attine ants and fungi are derived from lower attine ants and fungi, understanding the evolutionary transition from lower to higher attine agriculture requires understanding the historical sequence of change in both ants and fungi. The biology of the poorly known ant genus Mycetagroicus is of special interest in this regard because it occupies a phylogenetic position intermediate between lower and higher ant agriculture. Here, based on the excavations of four nests in Pará, Brazil, we report the first biological data for the recently described species Mycetagroicus inflatus, including the first descriptions of Mycetagroicus males and larvae. Like M. cerradensis, the only other species in the genus for which nesting biology is known, the garden chambers of M.inflatus are unusually deep and the garden is most likely relocated vertically in rainy and dry seasons. Due to the proximity of nests to the Araguaia River, it is likely that even the uppermost chambers and nest entrances of M. inflatus are submerged during the rainy season. Most remarkably, all three examined colonies of M. inflatus cultivate the same fungal species as their congener, M. cerradensis, over 1,000 km away, raising the possibility of long-term symbiont fidelity spanning speciation events within the genus.
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Affiliation(s)
- A. Jesovnik
- Department of Entomology, Maryland Center for Systematic Entomology, University of Maryland, 4112 Plant Science Bldg., College Park, MD 20742 USA
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, PO Box 37012, MRC 188 CE517, Washington, DC 20013-7012 USA
| | - J. Sosa-Calvo
- Department of Entomology, Maryland Center for Systematic Entomology, University of Maryland, 4112 Plant Science Bldg., College Park, MD 20742 USA
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, PO Box 37012, MRC 188 CE517, Washington, DC 20013-7012 USA
| | - C. T. Lopes
- Instituto de Biologia, Universidade Federal de Uberlândia, C.P. 593, 38400-902 Uberlândia, MG Brazil
| | - H. L. Vasconcelos
- Instituto de Biologia, Universidade Federal de Uberlândia, C.P. 593, 38400-902 Uberlândia, MG Brazil
| | - T. R. Schultz
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, PO Box 37012, MRC 188 CE517, Washington, DC 20013-7012 USA
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Instability of novel ant-fungal associations constrains horizontal exchange of fungal symbionts. Evol Ecol 2013. [DOI: 10.1007/s10682-013-9665-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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The bark beetle holobiont: why microbes matter. J Chem Ecol 2013; 39:989-1002. [PMID: 23846183 DOI: 10.1007/s10886-013-0318-8] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 06/19/2013] [Accepted: 06/27/2013] [Indexed: 01/20/2023]
Abstract
All higher organisms are involved in symbioses with microbes. The importance of these partnerships has led to the concept of the holobiont, defined as the animal or plant with all its associated microbes. Indeed, the interactions between insects and symbionts form much of the basis for the success and diversity of this group of arthropods. Insects rely on microbes to perform basic life functions and to exploit resources and habitats. By "partnering" with microbes, insects access new genomic variation instantaneously allowing the exploitation of new adaptive zones, influencing not only outcomes in ecological time, but the degree of innovation and change that occurs over evolutionary time. In this review, I present a brief overview of the importance of insect-microbe holobionts to illustrate how critical an understanding of the holobiont is to understanding the insect host and it interactions with its environment. I then review what is known about the most influential insect holobionts in many forest ecosystems-bark beetles and their microbes-and how new approaches and technologies are allowing us to illuminate how these symbioses function. Finally, I discuss why it will be critical to study bark beetles as a holobiont to understand the ramifications and extent of anthropogenic change in forest ecosystems.
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Kellner K, Fernández-Marín H, Ishak HD, Sen R, Linksvayer TA, Mueller UG. Co-evolutionary patterns and diversification of ant-fungus associations in the asexual fungus-farming ant Mycocepurus smithii
in Panama. J Evol Biol 2013; 26:1353-62. [DOI: 10.1111/jeb.12140] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 01/30/2013] [Accepted: 02/02/2013] [Indexed: 01/15/2023]
Affiliation(s)
- K. Kellner
- Section of Integrative Biology; Patterson Laboratories; University of Texas at Austin; Austin TX USA
| | - H. Fernández-Marín
- Smithsonian Tropical Research Institute; Balboa Panamá
- Instituto de Investigaciones Científicas y Servicios de Alta Tecnología; Panamá Rep. de Panamá
| | - H. D. Ishak
- Section of Integrative Biology; Patterson Laboratories; University of Texas at Austin; Austin TX USA
| | - R. Sen
- Department of Entomology; Purdue University; West Lafayette IN USA
| | - T. A. Linksvayer
- Department of Biology; University of Pennsylvania; Philadelphia PA USA
| | - U. G. Mueller
- Section of Integrative Biology; Patterson Laboratories; University of Texas at Austin; Austin TX USA
- Smithsonian Tropical Research Institute; Balboa Panamá
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de Vienne DM, Refrégier G, López-Villavicencio M, Tellier A, Hood ME, Giraud T. Cospeciation vs host-shift speciation: methods for testing, evidence from natural associations and relation to coevolution. THE NEW PHYTOLOGIST 2013; 198:347-385. [PMID: 23437795 DOI: 10.1111/nph.12150] [Citation(s) in RCA: 259] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 12/19/2012] [Indexed: 05/26/2023]
Abstract
Hosts and their symbionts are involved in intimate physiological and ecological interactions. The impact of these interactions on the evolution of each partner depends on the time-scale considered. Short-term dynamics - 'coevolution' in the narrow sense - has been reviewed elsewhere. We focus here on the long-term evolutionary dynamics of cospeciation and speciation following host shifts. Whether hosts and their symbionts speciate in parallel, by cospeciation, or through host shifts, is a key issue in host-symbiont evolution. In this review, we first outline approaches to compare divergence between pairwise associated groups of species, their advantages and pitfalls. We then consider recent insights into the long-term evolution of host-parasite and host-mutualist associations by critically reviewing the literature. We show that convincing cases of cospeciation are rare (7%) and that cophylogenetic methods overestimate the occurrence of such events. Finally, we examine the relationships between short-term coevolutionary dynamics and long-term patterns of diversification in host-symbiont associations. We review theoretical and experimental studies showing that short-term dynamics can foster parasite specialization, but that these events can occur following host shifts and do not necessarily involve cospeciation. Overall, there is now substantial evidence to suggest that coevolutionary dynamics of hosts and parasites do not favor long-term cospeciation.
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Affiliation(s)
- D M de Vienne
- Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), 08003, Barcelona, Spain
| | - G Refrégier
- Université Paris-Sud, Institut de Génétique et Microbiologie, UMR 8621, 91405, Orsay, France
- CNRS, UMR8621, 91405, Orsay, France
| | - M López-Villavicencio
- Muséum National d'Histoire Naturelle, 57 rue Cuvier, F-75231, Paris Cedex 05, France
| | - A Tellier
- Section of Population Genetics, Center of Life and Food Sciences Weihenstephan, Technische Universität München, D-85354, Freising, Germany
| | - M E Hood
- Department of Biology, Amherst College, Amherst, MA, USA
| | - T Giraud
- Université Paris-Sud, Ecologie, Systématique et Evolution, UMR 8079, 91405, Orsay, France
- CNRS, UMR8079, 91405, Orsay, France
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Laccase detoxification mediates the nutritional alliance between leaf-cutting ants and fungus-garden symbionts. Proc Natl Acad Sci U S A 2012; 110:583-7. [PMID: 23267060 DOI: 10.1073/pnas.1212709110] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Leaf-cutting ants combine large-scale herbivory with fungus farming to sustain advanced societies. Their stratified colonies are major evolutionary achievements and serious agricultural pests, but the crucial adaptations that allowed this mutualism to become the prime herbivorous component of neotropical ecosystems has remained elusive. Here we show how coevolutionary adaptation of a specific enzyme in the fungal symbiont has helped leaf-cutting ants overcome plant defensive phenolic compounds. We identify nine putative laccase-coding genes in the fungal genome of Leucocoprinus gongylophorus cultivated by the leaf-cutting ant Acromyrmex echinatior. One of these laccases (LgLcc1) is highly expressed in the specialized hyphal tips (gongylidia) that the ants preferentially eat, and we confirm that these ingested laccase molecules pass through the ant guts and remain active when defecated on the leaf pulp that the ants add to their gardens. This accurate deposition ensures that laccase activity is highest where new leaf material enters the fungus garden, but where fungal mycelium is too sparse to produce extracellular enzymes in sufficient quantities to detoxify phenolic compounds. Phylogenetic analysis of LgLcc1 ortholog sequences from symbiotic and free-living fungi revealed significant positive selection in the ancestral lineage that gave rise to the gongylidia-producing symbionts of leaf-cutting ants and their non-leaf-cutting ant sister group. Our results are consistent with fungal preadaptation and subsequent modification of a particular laccase enzyme for the detoxification of secondary plant compounds during the transition to active herbivory in the ancestor of leaf-cutting ants between 8 and 12 Mya.
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Seal JN, Gus J, Mueller UG. Fungus-gardening ants prefer native fungal species: do ants control their crops? Behav Ecol 2012. [DOI: 10.1093/beheco/ars109] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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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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Weber MG, Agrawal AA. Phylogeny, ecology, and the coupling of comparative and experimental approaches. Trends Ecol Evol 2012; 27:394-403. [DOI: 10.1016/j.tree.2012.04.010] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 04/20/2012] [Accepted: 04/23/2012] [Indexed: 11/27/2022]
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Symbiont fidelity and the origin of species in fungus-growing ants. Nat Commun 2012; 3:840. [DOI: 10.1038/ncomms1844] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Accepted: 04/12/2012] [Indexed: 11/08/2022] Open
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The Evolutionary Innovation of Nutritional Symbioses in Leaf-Cutter Ants. INSECTS 2012; 3:41-61. [PMID: 26467948 PMCID: PMC4553616 DOI: 10.3390/insects3010041] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Revised: 12/16/2011] [Accepted: 12/20/2011] [Indexed: 11/17/2022]
Abstract
Fungus-growing ants gain access to nutrients stored in plant biomass through their association with a mutualistic fungus they grow for food. This 50 million-year-old obligate mutualism likely facilitated some of these species becoming dominant Neotropical herbivores that can achieve immense colony sizes. Recent culture-independent investigations have shed light on the conversion of plant biomass into nutrients within ant fungus gardens, revealing that this process involves both the fungal cultivar and a symbiotic community of bacteria including Enterobacter, Klebsiella, and Pantoea species. Moreover, the genome sequences of the leaf-cutter ants Atta cephalotes and Acromyrmex echinatior have provided key insights into how this symbiosis has shaped the evolution of these ants at a genetic level. Here we summarize the findings of recent research on the microbial community dynamics within fungus-growing ant fungus gardens and discuss their implications for this ancient symbiosis.
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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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Nobre T, Koné NA, Konaté S, Linsenmair KE, Aanen DK. Dating the fungus-growing termites' mutualism shows a mixture between ancient codiversification and recent symbiont dispersal across divergent hosts. Mol Ecol 2011; 20:2619-27. [PMID: 21481052 DOI: 10.1111/j.1365-294x.2011.05090.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mutualistic symbiosis between fungus-growing termites and Termitomyces fungi originated in Africa and shows a moderate degree of interaction specificity. Here we estimate the age of the mutualism and test the hypothesis that the major splits have occurred simultaneously in the host and in the symbiont. We present a scenario where fungus-growing termites originated in the African rainforest just before the expansion of the savanna, about 31 Ma (19-49 Ma). Whereas rough age correspondence is observed for the four main clades of host and symbiont, the analysis reveals several recent events of host switching followed by dispersal of the symbiont throughout large areas and throughout different host genera. The most spectacular of these is a group of closely related fungi (the maximum age of which is estimated to be 2.4 Ma), shared between the divergent genera Microtermes, Ancistrotermes, Acanthotermes and Synacanthotermes (which diverged at least 16.7 Ma), and found throughout the African continent and on Madagascar. The lack of geographical differentiation of fungal symbionts shows that continuous exchange has occurred between regions and across host species.
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Affiliation(s)
- T Nobre
- Laboratory of Genetics, Wageningen University, Droevendaalsesteeg 1, Radix West, Building 107, 6708 PB Wageningen, The Netherlands.
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Mueller UG, Mikheyev AS, Solomon SE, Cooper M. Frontier mutualism: coevolutionary patterns at the northern range limit of the leaf-cutter ant-fungus symbiosis. Proc Biol Sci 2011; 278:3050-9. [PMID: 21389026 DOI: 10.1098/rspb.2011.0125] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Tropical leaf-cutter ants cultivate the fungus Attamyces bromatificus in a many-to-one, diffuse coevolutionary relationship where ant and fungal partners re-associate frequently over time. To evaluate whether ant-Attamyces coevolution is more specific (tighter) in peripheral populations, we characterized the host-specificities of Attamyces genotypes at their northern, subtropical range limits (southern USA, Mexico and Cuba). Population-genetic patterns of northern Attamyces reveal features that have so far not been observed in the diffusely coevolving, tropical ant-Attamyces associations. These unique features include (i) cases of one-to-one ant-Attamyces specialization that tighten coevolution at the northern frontier; (ii) distributions of genetically identical Attamyces clones over large areas (up to 81 000 km(2), approx. the area of Ireland, Austria or Panama); (iii) admixture rates between Attamyces lineages that appear lower in northern than in tropical populations; and (iv) long-distance gene flow of Attamyces across a dispersal barrier for leaf-cutter ants (ocean between mainland North America and Cuba). The latter suggests that Attamyces fungi may occasionally disperse independently of the ants, contrary to the traditional assumption that Attamyces fungi depend entirely on leaf-cutter queens for dispersal. Peripheral populations in Argentina or at mid-elevation sites in the Andes may reveal additional regional variants in ant-Attamyces coevolution. Studies of such populations are most likely to inform models of coextinctions of obligate mutualistic partners that are doubly stressed by habitat marginality and by environmental change.
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Affiliation(s)
- Ulrich G Mueller
- Section of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA.
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