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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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Pietrobon TDC, Kooij PW, Montoya QV, Rodrigues A. Escovopsioides nivea is a non-specific antagonistic symbiont of ant-fungal crops. FUNGAL ECOL 2022. [DOI: 10.1016/j.funeco.2022.101140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Dionisi M, Ozier-Lafontaine H, Laplace D. Control of Amazonian Leaf-Cutting Ants (Hymenoptera: Formicidae): A Multi-criteria Analysis. JOURNAL OF ECONOMIC ENTOMOLOGY 2021; 114:493-504. [PMID: 33547794 DOI: 10.1093/jee/toaa331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Indexed: 06/12/2023]
Abstract
Leaf-cutting ants (Hymenoptera: Formicidae) are one of the main pests found in the Americas and they cause global economic losses worth several billions of dollars. While pesticides have been the most widely used control method, new management alternatives in a context of agroecological transition are now being considered. This study focuses on the leaf-cutting ants species found in the pan-Amazon region. As part of efforts to improve management of these pests, this multi-criteria analysis of control strategies covers a total of 691 experiments collected from 153 studies, and the control were evaluated as a function of their management efficacy, environmental and human health impacts, and their ease of application. Chemical control methods were effective but posed a danger to human health and the environment, whereas mechanical methods and integrated management were more sustainable but not always very effective. Some of the biocontrol methods were evaluated as effective and safe for the environment and human health, including the use of entomopathogenic fungi Beauveria bassiana (Bals.-Criv) Vuill. (Hypocreales: Cordycipitaceae) and Metarhizium anisopliae (Metschn.) Sorokïn (Hypocreales: Clavicipitaceae) in the form of bait or sprayed in the nest, or the application of plant mulch in the nest using Tithonia diversifolia (Hemsley) A. Gray (Asterales: Asteraceae) or Canavalia ensiformis L. DC. (Fabales: Fabaceae). Because of variations in the efficacy data between laboratory and field tests, we are in favor of evaluating these control methods during field studies with different leaf-cutting ant species and under different environmental conditions. These methods should adopt experimental arrangements that are appropriate for local socioeconomic conditions adapted for farmers.
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Affiliation(s)
- Mathilde Dionisi
- INRAE, UR1321, ASTRO Agrosystèmes Tropicaux, Petit-Bourg, Guadeloupe, France
| | - Harry Ozier-Lafontaine
- INRAE, UR1321, ASTRO Agrosystèmes Tropicaux, Petit-Bourg, Guadeloupe, France
- DEAAF de Guyane, Service Salim, Unité OQA, Cayenne, Guyane, France
| | - Damien Laplace
- DEAAF de Guyane, Service Salim, Unité OQA, Cayenne, Guyane, France
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Barcoto MO, Pedrosa F, Bueno OC, Rodrigues A. Pathogenic nature of Syncephalastrum in Atta sexdens rubropilosa fungus gardens. PEST MANAGEMENT SCIENCE 2017; 73:999-1009. [PMID: 27539810 DOI: 10.1002/ps.4416] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 07/27/2016] [Accepted: 08/16/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND Leaf-cutter ants are considered to be a major herbivore and agricultural pest in the Neotropics. They are often controlled by environmentally persistent insecticides. Biological control using pathogenic fungi is regarded as an alternative for the management of these insects. Here, we assess whether the filamentous fungus Syncephalastrum sp. is a pathogenic microorganism responsible for a characteristic disease in fungus gardens. We also characterise the damage caused by this fungus by evaluating physiological and behavioural responses of Atta sexdens rubropilosa subcolonies infected with Syncephalastrum sp. RESULTS Syncephalastrum sp. fulfils Koch's postulates characterising it as a pathogenic microorganism. Ant workers recognise the infection and remove contaminated fragments from the fungus garden. Syncephalastrum sp. infection causes an interruption of foraging activity, an increase in ant mortality, subcolony deterioration and an increase in the amount of waste generated, all resulting in subcolony death. Syncephalastrum sp. also inhibits the ant fungal cultivar in vitro. The pathogenic effect of Syncephalastrum sp. does not depend on host morbidity or stress (e.g. worker mortality caused by an entomopathogenic fungus). CONCLUSION Syncephalastrum sp. treatment resulted in progressive damage in subcolonies. The interactions among Syncephalastrum sp., fungus garden and ants offer new opportunities in integrated pest management of leaf-cutter ants. © 2016 Society of Chemical Industry.
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Affiliation(s)
- Mariana O Barcoto
- Department of Biochemistry and Microbiology, UNESP - São Paulo State University, Rio Claro, São Paulo, Brazil
| | - Felipe Pedrosa
- Department of Ecology, UNESP - São Paulo State University, Rio Claro, São Paulo, Brazil
| | - Odair C Bueno
- Centre for the Study of Social Insects, UNESP - São Paulo State University, Rio Claro, São Paulo, Brazil
| | - Andre Rodrigues
- Department of Biochemistry and Microbiology, UNESP - São Paulo State University, Rio Claro, São Paulo, Brazil
- Centre for the Study of Social Insects, UNESP - São Paulo State University, Rio Claro, São Paulo, Brazil
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DeMilto AM, Rouquette M, Mueller UG, Kellner K, Seal JN. Effects of substrate, ant and fungal species on plant fiber degradation in a fungus-gardening ant symbiosis. JOURNAL OF INSECT PHYSIOLOGY 2017; 98:301-308. [PMID: 28193479 DOI: 10.1016/j.jinsphys.2017.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 02/03/2017] [Accepted: 02/06/2017] [Indexed: 06/06/2023]
Abstract
Fungus-gardening or attine ants have outsourced most of their digestive function to a symbiotic fungus. The ants feed their fungus - essentially an external digestive organ - a variety of substrates of botanical origin, including fresh and dried flowers, leaves and insect frass (processed leaves). Although plant tissues are rich in fibers (lignocelluloses, hemicelluloses, pectins and starches) and the symbiotic fungus possesses the genetic and enzymatic machinery to metabolize these compounds, the highly derived attines, the leaf-cutters (Atta and Acromyrmex), are known to produce fiber-rich waste. While leaf-cutting ants are important consumers of primary plant tissue, there have been fewer studies on physiological activity of fungi grown by closely related ant species in the genus Trachymyrmex, which generally grow related species of fungi, have smaller colonies and consume a wider variety of fungal substrates in addition to fresh leaves and flowers. In this study, we measured the cellulase activity of the fungus-gardening ants Atta texana, Trachymyrmex arizonensis and T. septentrionalis. We then quantified fiber consumption of the fungus-gardening ants Trachymyrmex septentrionalis and Trachymyrmex arizonensis by comparing the amounts and percentages present in their food and in fungus garden refuse during a controlled feeding experiment over the span of several months. Finally, we compared waste composition of T. arizonensis colonies growing different fungal strains, because this species is known to cultivate multiple strains of Leucoagaricus in its native range. The leaf-cutting ant A. texana was found to have lower cellulytic activity than T. arizonensis or T. septentrionalis. Total lignocellulose and hemicellulose amounts were significantly lower in refuse piles than in the substrates fed to the Trachymyrmex colonies, thus these fibers were consumed by the fungal symbionts of these ant species. Although lignocellulose utilization was similar in two distinct fungal species grown by T. arizonensis colonies, hemicellulose utilization was higher in T. arizonensis colonies growing a derived leaf-cutting ant fungal symbiont than when growing a native type of symbiont. The results of this study demonstrate that fiber digestion in fungus-gardening ants is an outcome of ant-fungal interaction.
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Affiliation(s)
- Alexandria M DeMilto
- Department of Biology, University of Texas at Tyler, 3900 University Blvd, Tyler, TX 75799, USA.
| | - Monte Rouquette
- Texas Agricultural Experiment Station, Texas A&M University Agricultural Research and Extension Center at Overton, Overton, TX 75684, USA.
| | - Ulrich G Mueller
- Integrative Biology, University of Texas at Austin, 1 University Station #C0930, Austin, TX 78712, USA.
| | - Katrin Kellner
- Department of Biology, University of Texas at Tyler, 3900 University Blvd, Tyler, TX 75799, USA.
| | - Jon N Seal
- Department of Biology, University of Texas at Tyler, 3900 University Blvd, Tyler, TX 75799, USA; Integrative Biology, University of Texas at Austin, 1 University Station #C0930, Austin, TX 78712, USA.
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Khadempour L, Burnum-Johnson KE, Baker ES, Nicora CD, Webb-Robertson BJM, White RA, Monroe ME, Huang EL, Smith RD, Currie CR. The fungal cultivar of leaf-cutter ants produces specific enzymes in response to different plant substrates. Mol Ecol 2016; 25:5795-5805. [PMID: 27696597 DOI: 10.1111/mec.13872] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 09/17/2016] [Accepted: 09/19/2016] [Indexed: 01/20/2023]
Abstract
Herbivores use symbiotic microbes to help derive energy and nutrients from plant material. Leaf-cutter ants are a paradigmatic example, cultivating their mutualistic fungus Leucoagaricus gongylophorus on plant biomass that workers forage from a diverse collection of plant species. Here, we investigate the metabolic flexibility of the ants' fungal cultivar for utilizing different plant biomass. Using feeding experiments and a novel approach in metaproteomics, we examine the enzymatic response of L. gongylophorus to leaves, flowers, oats or a mixture of all three. Across all treatments, our analysis identified and quantified 1766 different fungal proteins, including 161 putative biomass-degrading enzymes. We found significant differences in the protein profiles in the fungus gardens of subcolonies fed different plant substrates. When provided with leaves or flowers, which contain the majority of their energy as recalcitrant plant polymers, the fungus gardens produced more proteins predicted to break down cellulose: endoglucanase, exoglucanase and β-glucosidase. Further, the complete metaproteomes for the leaves and flowers treatments were very similar, while the mixed substrate treatment closely resembled the treatment with oats alone. This indicates that when provided a mixture of plant substrates, fungus gardens preferentially break down the simpler, more digestible substrates. This flexible, substrate-specific enzymatic response of the fungal cultivar allows leaf-cutter ants to derive energy from a wide range of substrates, which likely contributes to their ability to be dominant generalist herbivores.
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Affiliation(s)
- Lily Khadempour
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, USA.,Department of Zoology, University of Wisconsin-Madison, Madison, WI, 53706, USA.,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | | | - Erin S Baker
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Carrie D Nicora
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | | | - Richard A White
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Matthew E Monroe
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Eric L Huang
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Richard D Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Cameron R Currie
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, USA.,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, 53706, USA
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Wallenstein MD, Burns RG. Ecology of Extracellular Enzyme Activities and Organic Matter Degradation in Soil: A Complex Community-Driven Process. SSSA BOOK SERIES 2015. [DOI: 10.2136/sssabookser9.c2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
| | - Richard G. Burns
- School of Agriculture and Food Sciences; University of Queensland; Brisbane Australia
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Leaf-cutter ant fungus gardens are biphasic mixed microbial bioreactors that convert plant biomass to polyols with biotechnological applications. Appl Environ Microbiol 2015; 81:4525-35. [PMID: 25911490 DOI: 10.1128/aem.00046-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 04/21/2015] [Indexed: 11/20/2022] Open
Abstract
Leaf-cutter ants use plant matter to culture the obligate mutualistic basidiomycete Leucoagaricus gongylophorus. This fungus mediates ant nutrition on plant resources. Furthermore, other microbes living in the fungus garden might also contribute to plant digestion. The fungus garden comprises a young sector with recently incorporated leaf fragments and an old sector with partially digested plant matter. Here, we show that the young and old sectors of the grass-cutter Atta bisphaerica fungus garden operate as a biphasic solid-state mixed fermenting system. An initial plant digestion phase occurred in the young sector in the fungus garden periphery, with prevailing hemicellulose and starch degradation into arabinose, mannose, xylose, and glucose. These products support fast microbial growth but were mostly converted into four polyols. Three polyols, mannitol, arabitol, and inositol, were secreted by L. gongylophorus, and a fourth polyol, sorbitol, was likely secreted by another, unidentified, microbe. A second plant digestion phase occurred in the old sector, located in the fungus garden core, comprising stocks of microbial biomass growing slowly on monosaccharides and polyols. This biphasic operation was efficient in mediating symbiotic nutrition on plant matter: the microbes, accounting for 4% of the fungus garden biomass, converted plant matter biomass into monosaccharides and polyols, which were completely consumed by the resident ants and microbes. However, when consumption was inhibited through laboratory manipulation, most of the plant polysaccharides were degraded, products rapidly accumulated, and yields could be preferentially switched between polyols and monosaccharides. This feature might be useful in biotechnology.
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Duarte APM, Attili-Angelis D, Baron NC, Forti LC, Pagnocca FC. Leaf-cutting ants: an unexpected microenvironment holding human opportunistic black fungi. Antonie van Leeuwenhoek 2014; 106:465-73. [PMID: 24969946 DOI: 10.1007/s10482-014-0215-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 06/11/2014] [Indexed: 11/26/2022]
Abstract
Fungus-growing ants of the genus Atta are known for their leaf-cutting habit, a lifestyle they have maintained since their 50-million-year-old co-evolution with a mutualistic fungus, cultivated as food. Recent studies have highlighted that, in addition to the mutualistic fungus, nests of ants harbor a great diversity of microbial communities. Such microorganisms include the dematiaceous fungi, which are characterized by their melanized cell walls. In order to contribute to the knowledge of fungal ecology, as well as opportunistic strains that may be dispersed by these social insects, we isolated and identified fungi carried by gynes of Atta capiguara and Atta laevigata, collected from colonies located in Fazenda Santana, Botucatu (São Paulo, Brazil). The isolation was carried out using the oil flotation technique, which is suitable for the growth of black fungi. Inoculated plates were incubated at 25 and 35 °C until black cultures were visible (20-45 days). Isolates were identified based on microscopic and molecular characteristics. Some isolated genera were: Cladophialophora, Cladosporium, Exophiala, Ochroconis, Phaeococcomyces, Phialophora and Penidiella. Hyaline species were also found. The results obtained from this work showed that leaf-cutting gynes may contribute to the dispersal of opportunistic dematiaceous fungi. It is suggested that more attention should be paid to this still unexplored subject.
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Affiliation(s)
- A P M Duarte
- Center for the Study of Social Insects, UNESP - São Paulo State University, Rio Claro, SP, Brazil
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Lange L, Grell MN. The prominent role of fungi and fungal enzymes in the ant–fungus biomass conversion symbiosis. Appl Microbiol Biotechnol 2014; 98:4839-51. [DOI: 10.1007/s00253-014-5708-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 03/15/2014] [Accepted: 03/17/2014] [Indexed: 10/25/2022]
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Hansen AK, Moran NA. The impact of microbial symbionts on host plant utilization by herbivorous insects. Mol Ecol 2013; 23:1473-1496. [PMID: 23952067 DOI: 10.1111/mec.12421] [Citation(s) in RCA: 274] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 06/02/2013] [Accepted: 06/12/2013] [Indexed: 01/18/2023]
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Bacci M, Bueno OC, Rodrigues A, Pagnocca FC, Somera AF, Silva A. A metabolic pathway assembled by enzyme selection may support herbivory of leaf-cutter ants on plant starch. JOURNAL OF INSECT PHYSIOLOGY 2013; 59:525-31. [PMID: 23500892 DOI: 10.1016/j.jinsphys.2013.02.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 02/13/2013] [Accepted: 02/15/2013] [Indexed: 05/24/2023]
Abstract
Mutualistic associations shape the evolution in different organism groups. The association between the leaf-cutter ant Atta sexdens and the basidiomycete fungus Leucoagaricus gongylophorus has enabled them to degrade starch from plant material generating glucose, which is a major food source for both mutualists. Starch degradation is promoted by enzymes contained in the fecal fluid that ants deposit on the fungus culture in cut leaves inside the nests. To understand the dynamics of starch degradation in ant nests, we purified and characterized starch degrading enzymes from the ant fecal fluid and from laboratory cultures of L. gongylophorus and found that the ants intestine positively selects fungal α-amylase and a maltase likely produced by the ants, as a negative selection is imposed to fungal maltase and ant α-amylases. Selected enzymes are more resistant to catabolic repression by glucose and proposed to structure a metabolic pathway in which the fungal α-amylase initiates starch catalysis to generate byproducts which are sequentially degraded by the maltase to produce glucose. The pathway is responsible for effective degradation of starch and proposed to represent a major evolutionary innovation enabling efficient starch assimilation from plant material by leaf-cutters.
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Affiliation(s)
- Maurício Bacci
- Universidade Estadual Paulista, Instituto de Biociências de Rio Claro, Centro de Estudos de Insetos Sociais/Departamento de Bioquímica e Microbiologia, Brazil.
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Boulogne I, Ozier-Lafontaine H, Germosén-Robineau L, Desfontaines L, Loranger-Merciris G. Acromyrmex octospinosus (Hymenoptera: Formicidae) management: effects of TRAMILs fungicidal plant extracts. JOURNAL OF ECONOMIC ENTOMOLOGY 2012; 105:1224-1233. [PMID: 22928301 DOI: 10.1603/ec11313] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Leaf-cutting ants, Acromyrmex octospinosus (Reich), are considering among the most important pest species of the New World. Until now, the main insecticides used for controlling these ants were synthetic chemicals. Leaf-cutting ants live in obligate symbiosis with abasidiomycete fungus, Leucocoprinus gongylophorus (Heim) Moeller. The crucial role of this symbiotic partner in the nest of leaf-cutting ants has prompted us to focus on A. octospinosus management through the use of fungicides in our study. Five parts of plants identified for their antifungal potential through TRAMIL ethnopharmacological surveys were tested: 1) bulbs of Allium cepa L.; 2) seed pods of Allium sativum L.; 3) green fruits of Lycopersicon esculentum L.; 4) leaves of Manihot esculenta Crantz; and 5) leaves of Senna alata (L.) Roxburgh. One plant extract with strong fungicidal activity (S. alata) against L. gongylophorus was found. The other extracts had lesser fungistatic or fungicidal effects depending on the concentrations used. The data presented in this study showed that TRAMILs fungicidal plant extracts have potential to control the symbiotic fungus of leaf cutting ants, in particular a foliage extract of S. alata.
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Affiliation(s)
- Isabelle Boulogne
- Université des Antilles et de la Guyane, UFR Sciences Exactes et Naturelles, Campus de Fouillole, 97157 Pointe-à-Pitre Cedex, Guadeloupe.
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Metagenomic and metaproteomic insights into bacterial communities in leaf-cutter ant fungus gardens. ISME JOURNAL 2012; 6:1688-701. [PMID: 22378535 DOI: 10.1038/ismej.2012.10] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Herbivores gain access to nutrients stored in plant biomass largely by harnessing the metabolic activities of microbes. Leaf-cutter ants of the genus Atta are a hallmark example; these dominant neotropical herbivores cultivate symbiotic fungus gardens on large quantities of fresh plant forage. As the external digestive system of the ants, fungus gardens facilitate the production and sustenance of millions of workers. Using metagenomic and metaproteomic techniques, we characterize the bacterial diversity and physiological potential of fungus gardens from two species of Atta. Our analysis of over 1.2 Gbp of community metagenomic sequence and three 16S pyrotag libraries reveals that in addition to harboring the dominant fungal crop, these ecosystems contain abundant populations of Enterobacteriaceae, including the genera Enterobacter, Pantoea, Klebsiella, Citrobacter and Escherichia. We show that these bacterial communities possess genes associated with lignocellulose degradation and diverse biosynthetic pathways, suggesting that they play a role in nutrient cycling by converting the nitrogen-poor forage of the ants into B-vitamins, amino acids and other cellular components. Our metaproteomic analysis confirms that bacterial glycosyl hydrolases and proteins with putative biosynthetic functions are produced in both field-collected and laboratory-reared colonies. These results are consistent with the hypothesis that fungus gardens are specialized fungus-bacteria communities that convert plant material into energy for their ant hosts. Together with recent investigations into the microbial symbionts of vertebrates, our work underscores the importance of microbial communities in the ecology and evolution of herbivorous metazoans.
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Mendes TD, Rodrigues A, Dayo-Owoyemi I, Marson FAL, Pagnocca FC. Generation of Nutrients and Detoxification: Possible Roles of Yeasts in Leaf-Cutting Ant Nests. INSECTS 2012; 3:228-45. [PMID: 26467957 PMCID: PMC4553625 DOI: 10.3390/insects3010228] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Revised: 02/12/2012] [Accepted: 02/13/2012] [Indexed: 11/20/2022]
Abstract
The possible roles played by yeasts in attine ant nests are mostly unknown. Here we present our investigations on the plant polysaccharide degradation profile of 82 yeasts isolated from fungus gardens of Atta and Acromyrmex species to demonstrate that yeasts found in ant nests may play the role of making nutrients readily available throughout the garden and detoxification of compounds that may be deleterious to the ants and their fungal cultivar. Among the yeasts screened, 65% exhibited cellulolytic enzymes, 44% exhibited pectinolytic activity while 27% and 17% possess enzyme systems for the degradation of protease and amylase, respectively. Galacturonic acid, which had been reported in previous work to be poorly assimilated by the ant fungus and also to have a negative effect on ants’ survival, was assimilated by 64% and 79% of yeasts isolated from nests of A. texana and Acromyrmex respectively. Our results suggest that yeasts found in ant nests may participate in generation of nutrients and removal of potentially toxic compounds, thereby contributing to the stability of the complex microbiota found in the leaf-cutting ant nests.
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Affiliation(s)
- Thais D Mendes
- EMBRAPA-Agroenergy/Parque Estação Biológica, Brasília, DF 70770-901, Brazil.
| | - André Rodrigues
- Department of Biochemistry and Microbiology, UNESP-São Paulo State University, Rio Claro, SP 13506-900, Brazil.
| | - Ifeloju Dayo-Owoyemi
- Department of Biochemistry and Microbiology, UNESP-São Paulo State University, Rio Claro, SP 13506-900, Brazil.
- Centre for the Study of Social Insects, UNESP-São Paulo State University, Rio Claro, SP 13506-900, Brazil.
| | - Fernando A L Marson
- Centre for the Study of Social Insects, UNESP-São Paulo State University, Rio Claro, SP 13506-900, Brazil.
| | - Fernando C Pagnocca
- Department of Biochemistry and Microbiology, UNESP-São Paulo State University, Rio Claro, SP 13506-900, Brazil.
- Centre for the Study of Social Insects, UNESP-São Paulo State University, Rio Claro, SP 13506-900, Brazil.
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Boulogne I, Germosen-Robineau L, Ozier-Lafontaine H, Jacoby-Koaly C, Aurela L, Loranger-Merciris G. Acromyrmex octospinosus (Hymenoptera: Formicidae) management. Part 1: Effects of TRAMIL's insecticidal plant extracts. PEST MANAGEMENT SCIENCE 2012; 68:313-320. [PMID: 21858911 DOI: 10.1002/ps.2267] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 06/25/2011] [Accepted: 06/27/2011] [Indexed: 05/31/2023]
Abstract
BACKGROUND Leaf-cutting ants are considered to be one of the most important pest species of the New World. Until now, control strategies against these leaf-cutting ants have mainly been synthetic chemicals. The aim of the present study was to test the action of several plant extracts quoted as an example by TRAMIL participative surveys for their insecticidal properties on adult major workers of Acromyrmex octospinosus. Three tests were used to that end: contact toxicity, repellent test and ingestion bioassay. Six traditional plant uses recommended by interviewed people in surveys were tested: (1) maceration of Mammea americana fresh crushed seeds; (2) decoction of Nerium oleander fresh leaves; (3) Nerium oleander dried leaf water juice; (4) decoction of Nicotiana tabacum dried leaves; (5) Trichillia pallida dried leaf water juice; (6) decoction of Rollinia mucosa dried seeds. RESULTS Two plant extracts with contact toxicity (Mammea americana and Nicotiana tabacum), six plant extracts with repellent activity and four plant extracts with ingestion toxicity (Mammea americana, Nicotiana tabacum and both extracts of Nerium oleander) were found. CONCLUSION The data presented in this study showed that plant extracts cited by TRAMIL ethnopharmacological surveys have the potential to control the leaf-cutting ant, Acromyrmex octospinosus. In particular, the Mammea americana extract, with its natural low repellent effect and its high toxicity by ingestion, and Nerium oleander extracts, with their natural delay action, are possibly the best extracts for the control of these ants.
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Affiliation(s)
- Isabelle Boulogne
- INRA, UR1321, ASTRO Agrosystèmes Tropicaux, Petit-Bourg, Guadeloupe.
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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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Selective isolation of dematiaceous fungi from the workers of Atta laevigata (Formicidae: Attini). Folia Microbiol (Praha) 2011; 57:21-6. [DOI: 10.1007/s12223-011-0081-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 10/19/2011] [Indexed: 10/14/2022]
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Kooij PW, Schiøtt M, Boomsma JJ, De Fine Licht HH. Rapid shifts in Atta cephalotes fungus-garden enzyme activity after a change in fungal substrate (Attini, Formicidae). INSECTES SOCIAUX 2011; 58:145-151. [PMID: 21475686 PMCID: PMC3059815 DOI: 10.1007/s00040-010-0127-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 10/08/2010] [Accepted: 10/13/2010] [Indexed: 05/30/2023]
Abstract
Fungus gardens of the basidiomycete Leucocoprinus gongylophorus sustain large colonies of leaf-cutting ants by degrading the plant material collected by the ants. Recent studies have shown that enzyme activity in these gardens is primarily targeted toward starch, proteins and the pectin matrix associated with cell walls, rather than toward structural cell wall components such as cellulose and hemicelluloses. Substrate constituents are also known to be sequentially degraded in different sections of the fungus garden. To test the plasticity in the extracellular expression of fungus-garden enzymes, we measured the changes in enzyme activity after a controlled shift in fungal substrate offered to six laboratory colonies of Atta cephalotes. An ant diet consisting exclusively of grains of parboiled rice rapidly increased the activity of endo-proteinases and some of the pectinases attacking the backbone structure of pectin molecules, relative to a pure diet of bramble leaves, and this happened predominantly in the most recently established top sections of fungus gardens. However, fungus-garden amylase activity did not significantly increase despite the substantial increase in starch availability from the rice diet, relative to the leaf diet controls. Enzyme activity in the older, bottom sections of fungus gardens decreased, indicating a faster processing of the rice substrate compared to the leaf diet. These results suggest that leaf-cutting ant fungus gardens can rapidly adjust enzyme activity to provide a better match with substrate availability and that excess starch that is not protected by cell walls may be digested by the ants rather than by the fungus-garden symbiont. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00040-010-0127-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- P. W. Kooij
- Department of Biology, Centre for Social Evolution, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
- Laboratory of Genetics, Plant Sciences Group, Wageningen University and Research Center, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - M. Schiøtt
- Department of Biology, Centre for Social Evolution, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - J. J. Boomsma
- Department of Biology, Centre for Social Evolution, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - H. H. De Fine Licht
- Department of Biology, Centre for Social Evolution, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
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Moller IE, De Fine Licht HH, Harholt J, Willats WGT, Boomsma JJ. The dynamics of plant cell-wall polysaccharide decomposition in leaf-cutting ant fungus gardens. PLoS One 2011; 6:e17506. [PMID: 21423735 PMCID: PMC3053354 DOI: 10.1371/journal.pone.0017506] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Accepted: 02/04/2011] [Indexed: 11/18/2022] Open
Abstract
The degradation of live plant biomass in fungus gardens of leaf-cutting ants is poorly characterised but fundamental for understanding the mutual advantages and efficiency of this obligate nutritional symbiosis. Controversies about the extent to which the garden-symbiont Leucocoprinus gongylophorus degrades cellulose have hampered our understanding of the selection forces that induced large scale herbivory and of the ensuing ecological footprint of these ants. Here we use a recently established technique, based on polysaccharide microarrays probed with antibodies and carbohydrate binding modules, to map the occurrence of cell wall polymers in consecutive sections of the fungus garden of the leaf-cutting ant Acromyrmex echinatior. We show that pectin, xyloglucan and some xylan epitopes are degraded, whereas more highly substituted xylan and cellulose epitopes remain as residuals in the waste material that the ants remove from their fungus garden. These results demonstrate that biomass entering leaf-cutting ant fungus gardens is only partially utilized and explain why disproportionally large amounts of plant material are needed to sustain colony growth. They also explain why substantial communities of microbial and invertebrate symbionts have evolved associations with the dump material from leaf-cutting ant nests, to exploit decomposition niches that the ant garden-fungus does not utilize. Our approach thus provides detailed insight into the nutritional benefits and shortcomings associated with fungus-farming in ants.
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Affiliation(s)
- Isabel E Moller
- Copenhagen Biocenter, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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Pagnocca FC, Legaspe MFC, Rodrigues A, Ruivo CCC, Nagamoto NS, Bacci M, Forti LC. Yeasts isolated from a fungus-growing ant nest, including the description of Trichosporon chiarellii sp. nov., an anamorphic basidiomycetous yeast. Int J Syst Evol Microbiol 2009; 60:1454-1459. [PMID: 19671730 DOI: 10.1099/ijs.0.015727-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Thirty-nine yeast strains were recovered from a field nest of a primitive and putative novel attine ant species in the genus Myrmicocrypta (Hymenoptera: Formicidae: tribe Attini). Yeasts isolated from the fungus garden and waste deposit included Candida dubliniensis, Candida oleophila, Cryptococcus haglerorum and Hanseniaspora uvarum. In addition, one morphological type was isolated overwhelmingly. Sequencing data of partial large-subunit (LSU) rDNA and the internal transcribed spacer (ITS) region coupled with morphological and physiological characterization accommodated this morphotype in a separate taxonomic position in relation to the known species of Trichosporon (Basidiomycota: Trichosporonales). Here, we propose a novel yeast species named Trichosporon chiarellii sp. nov. based on the description of 34 isolates; the type strain is strain FCP 540806(T) (=CBS 11177(T)).
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Affiliation(s)
- Fernando C Pagnocca
- Center for the Study of Social Insects, UNESP - São Paulo State University, 13506-900, Rio Claro, SP, Brazil
| | - Mara F C Legaspe
- Center for the Study of Social Insects, UNESP - São Paulo State University, 13506-900, Rio Claro, SP, Brazil
| | - Andre Rodrigues
- Center for the Study of Social Insects, UNESP - São Paulo State University, 13506-900, Rio Claro, SP, Brazil
| | - Carla C C Ruivo
- Center for the Study of Social Insects, UNESP - São Paulo State University, 13506-900, Rio Claro, SP, Brazil
| | - Nilson S Nagamoto
- Department of Vegetal Production, UNESP - São Paulo State University, 18603-970, Botucatu, SP, Brazil
| | - Maurício Bacci
- Center for the Study of Social Insects, UNESP - São Paulo State University, 13506-900, Rio Claro, SP, Brazil
| | - Luiz C Forti
- Department of Vegetal Production, UNESP - São Paulo State University, 18603-970, Botucatu, SP, Brazil
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Erthal M, Silva CP, Cooper RM, Samuels RI. Hydrolytic enzymes of leaf-cutting ant fungi. Comp Biochem Physiol B Biochem Mol Biol 2008; 152:54-9. [PMID: 18848636 DOI: 10.1016/j.cbpb.2008.09.086] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Revised: 09/17/2008] [Accepted: 09/17/2008] [Indexed: 11/16/2022]
Abstract
The production of enzymes and the colonization of leaves by Leucoagaricus gongylophorus were investigated to further understand the digestive interactions of leaf-cutting ant colonies. The enzymes detected were indicative of a saprophytic origin of this fungus, producing all the enzymes necessary for plant tissue breakdown. Enhanced activities of certain enzymes in the fungus garden extracts may be due to the particular behaviour of the adult worker ants that concentrate fungal acquired enzymes in the rectal fluid and subsequently defaecate these enzymes onto the leaves. The production of chitinases by the fungus may be an ancestral vestige of lower attines, and may have a role as agonists of invading microbes. Growth of the fungus on plant cell wall medium resulted in highest enzyme activity against pectin, reflecting the fact that polygalacturonans comprise the main matrix of the primary plant cell wall. SEM shows that L. gongylophorus does not form specialized structures for cell wall penetration, but gains access to the inner plant tissue at the cut edges of the leaf fragments. Enzymes secreted by the fungus were compared to those seen in larval and adult leaf-cutting ants, demonstrating the inter-dependence of the symbiotic relationship between the ants and their fungi.
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Affiliation(s)
- Milton Erthal
- Instituto Superior de Tecnologia em Ciências Agrárias - FAETEC, Campos dos Goytacazes, RJ, Brazil
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Yeasts and filamentous fungi carried by the gynes of leaf-cutting ants. Antonie van Leeuwenhoek 2008; 94:517-26. [DOI: 10.1007/s10482-008-9268-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Accepted: 07/09/2008] [Indexed: 10/21/2022]
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Schiøtt M, De Fine Licht HH, Lange L, Boomsma JJ. Towards a molecular understanding of symbiont function: identification of a fungal gene for the degradation of xylan in the fungus gardens of leaf-cutting ants. BMC Microbiol 2008; 8:40. [PMID: 18307762 PMCID: PMC2291056 DOI: 10.1186/1471-2180-8-40] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Accepted: 02/28/2008] [Indexed: 11/30/2022] Open
Abstract
Background Leaf-cutting ants live in symbiosis with a fungus that they rear for food by providing it with live plant material. Until recently the fungus' main inferred function was to make otherwise inaccessible cell wall degradation products available to the ants, but new studies have shed doubt on this idea. To provide evidence for the cell wall degrading capacity of the attine ant symbiont, we designed PCR primers from conserved regions of known xylanase genes, to be used in PCR with genomic DNA from the symbiont as template. We also measured xylanase, cellulase and proteinase activities in the fungus gardens in order to investigate the dynamics of degradation activities. Results We cloned a xylanase gene from the mutualistic fungus of Acromyrmex echinatior, determined its protein sequence, and inserted it in a yeast expression vector to confirm its substrate specificity. Our results show that the fungus has a functional xylanase gene. We also show by lab experiments in vivo that the activity of fungal xylanase and cellulase is not evenly distributed, but concentrated in the lower layer of fungus gardens, with only modest activity in the middle layer where gongylidia are produced and intermediate activity in the newly established top layer. This vertical distribution appears to be negatively correlated with the concentration of glucose, which indicates a directly regulating role of glucose, as has been found in other fungi and has been previously suggested for the ant fungal symbiont. Conclusion The mutualistic fungus of Acromyrmex echinatior has a functional xylanase gene and is thus presumably able to at least partially degrade the cell walls of leaves. This finding supports a saprotrophic origin of the fungal symbiont. The observed distribution of enzyme activity leads us to propose that leaf-substrate degradation in fungus gardens is a multi-step process comparable to normal biodegradation of organic matter in soil ecosystems, but with the crucial difference that a single fungal symbiont realizes most of the steps that are normally provided by a series of microorganisms that colonize fallen leaves in a distinct succession.
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Affiliation(s)
- Morten Schiøtt
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark.
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Wu B, Hu GK, Feng H, Wu JM, Zhang YZ. Cloning and Expression of an α-Amylase Gene from Phanerochaete chrysosporium. Curr Microbiol 2007; 55:105-13. [PMID: 17597340 DOI: 10.1007/s00284-006-0600-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2006] [Accepted: 02/08/2007] [Indexed: 11/26/2022]
Abstract
Based on the genomic sequence and cDNA library screening, the cDNA sequence encoding an alpha-amylase was cloned from the filamentous white-rot fungus Phanerochaete chrysosporium and designated as pcamy1. Alignment results showed that the predicted protein has up to 43% amino acid homology to the known alpha-amylases in other organisms and is close to those from some filamentous fungi. Under nitrogen-starvation condition, the transcription of pcamy1 was accordingly upregulated or downregulated when soluble starch or glucose is sole carbon source. Addition of oxygen to nitrogen-limited media led to pcamy1 transcription and removal of glucose metabolic repression. The result indicated that the pcamy1 transcript was not only regulated by nutrients such as the carbon source but also by the cultivation environment, such as oxygen. This coordinate-regulatory model is likely common in P. chrysosporium. The expressed product of this gene in Escherichia coli could hydrolyze soluble starch, and its enzymatic activity was determined. As far as we know, this is the first report about cloning and expression study on the alpha-amylase in P. chrysosporium.
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Affiliation(s)
- Bo Wu
- College of Life Sciences, Sichuan Key Laboratory of Molecular Biology and Biotechnology, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, Sichuan Province, PR China
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