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Almeida BK, Tran EH, Afkhami ME. Phyllosphere fungal diversity generates pervasive nonadditive effects on plant performance. THE NEW PHYTOLOGIST 2024; 243:2416-2429. [PMID: 38719779 DOI: 10.1111/nph.19792] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 04/01/2024] [Indexed: 08/23/2024]
Abstract
Plants naturally harbor diverse microbiomes that can dramatically impact their health and productivity. However, it remains unclear how fungal microbiome diversity, especially in the phyllosphere, impacts intermicrobial interactions and consequent nonadditive effects on plant productivity. Combining manipulative experiments, field collections, culturing, microbiome sequencing, and synthetic consortia, we experimentally tested for the first time how foliar fungal community diversity impacts plant productivity. We inoculated morning glories (Ipomoea hederifolia L.) with 32 phyllosphere consortia of either low or high diversity or with single fungal taxa, and measured effects on plant productivity and allocation. We found the following: (1) nonadditive effects were pervasive with 56% of fungal consortia interacting synergistically or antagonistically to impact plant productivity, including some consortia capable of generating acute synergism (e.g. > 1000% increase in productivity above the additive expectation), (2) interactions among 'commensal' fungi were responsible for this nonadditivity in diverse consortia, (3) synergistic interactions were approximately four times stronger than antagonistic effects, (4) fungal diversity affected the magnitude but not frequency or direction of nonadditivity, and (5) diversity affected plant performance nonlinearly with the highest performance in low-diversity treatments. These findings highlight the importance of interpreting plant-microbiome interactions under a framework that incorporates intermicrobial interactions and nonadditive outcomes to understand natural complexity.
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Affiliation(s)
- Brianna K Almeida
- Department of Biology, University of Miami, Coral Gables, FL, 33146, USA
| | - Elan H Tran
- Department of Biology, University of Miami, Coral Gables, FL, 33146, USA
| | - Michelle E Afkhami
- Department of Biology, University of Miami, Coral Gables, FL, 33146, USA
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2
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Zhang W, Forester NT, Chettri P, Heilijgers M, Mace WJ, Maes E, Morozova Y, Applegate ER, Johnson RD, Johnson LJ. Characterization of the Biosynthetic Gene Cluster for the Ribosomally Synthesized Cyclic Peptide Epichloëcyclins in Epichloë festucae. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:13965-13978. [PMID: 37704203 PMCID: PMC10540207 DOI: 10.1021/acs.jafc.3c03073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 08/14/2023] [Accepted: 08/16/2023] [Indexed: 09/15/2023]
Abstract
The various grass-induced epichloëcyclins of the Epichloë spp. are ribosomally synthesized and post-translationally modified peptides (RiPPs), produced as small, secreted cyclopeptides from a single gene, gigA. Here, four clustered and coregulated genes (gigA, gigB, gigC, and kexB) with predicted roles in epichloëcyclin production in Epichloë festucae were evaluated through gene disruption. Subsequent chemical analysis indicates that GigB is a DUF3328 domain-containing protein associated with cyclization of epichloëcyclins; GigC is a methyltransferase enzyme responsible for N-methylation of desmethylepichloëcyclins; and KexB is a subtilisin-like enzyme, partly responsible for the propeptide cleavage of epichloëcyclin intermediates. Symbiotic effects on the host phenotype were not observed for gigA, gigC, or kexB mutants, although ΔgigB infection correlated with increased host tiller height and biomass, while only ΔkexB exhibited an effect on endophyte morphology. Disrupting epichloëcyclin biosynthesis showed negligible influence on the biosynthesis of E. festucae-associated alkaloids. Epichloëcyclins may perform other secondary metabolism functions in Epichloë and other fungi.
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Affiliation(s)
- Wei Zhang
- Grasslands
Research Centre, AgResearch Limited, Palmerston North 4442, New Zealand
| | - Natasha T. Forester
- Grasslands
Research Centre, AgResearch Limited, Palmerston North 4442, New Zealand
| | - Pranav Chettri
- Grasslands
Research Centre, AgResearch Limited, Palmerston North 4442, New Zealand
| | - Maurice Heilijgers
- Grasslands
Research Centre, AgResearch Limited, Palmerston North 4442, New Zealand
| | - Wade J. Mace
- Grasslands
Research Centre, AgResearch Limited, Palmerston North 4442, New Zealand
| | - Evelyne Maes
- Lincoln
Research Centre, AgResearch Limited, Lincoln 7608, New Zealand
| | - Yulia Morozova
- Grasslands
Research Centre, AgResearch Limited, Palmerston North 4442, New Zealand
| | - Emma R. Applegate
- Grasslands
Research Centre, AgResearch Limited, Palmerston North 4442, New Zealand
| | - Richard D. Johnson
- Grasslands
Research Centre, AgResearch Limited, Palmerston North 4442, New Zealand
| | - Linda J. Johnson
- Grasslands
Research Centre, AgResearch Limited, Palmerston North 4442, New Zealand
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3
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Górzyńska K, Olejniczak P, Węgrzyn E. The fungus Clonostachys epichloë alters the influence of the Epichloë endophyte on seed germination and the biomass of Puccinellia distans grass. Front Microbiol 2023; 14:1146061. [PMID: 37434716 PMCID: PMC10330949 DOI: 10.3389/fmicb.2023.1146061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 06/08/2023] [Indexed: 07/13/2023] Open
Abstract
The fungal grass endophyte Epichloë typhina (Pers.) Tul. & C. Tul. (Ascomycota: Clavicipitaceae) grows intercellulary in aerial plant parts and reproduces asexually by invading host seeds. In this phase, it enhances seed production and germination, which accelerates its vertical spread. This relationship may be distorted by other seed-born fungi, whose spread is not so directly dependent on the success of the grass. Recently, the fungus Clonostachys epichloë Schroers has been observed on Puccinellia distans (Jacq.) Parl seeds originating from grass clumps infested with stromata, sexual structures of Epichloë typhina that are formed in spring on some host culms, preventing flower and seed development ('choke disease'). C. epichloë shows mycoparasitic activity toward Epichloë stromata by reducing the production of ascospores, which are responsible for horizontal transmission of the fungus. The aim of this study was to investigate the effect of seed-borne C. epichloë on seed germination, as well as the size and weight of P. distans seedlings and to examine whether C. epichloë alters the influence of Epichloë in the early developmental stages of P. distans. The results showed that if C. epichloë acts on seeds together with E. typhina endophytes, the seeds were negatively affected due to the elimination of the positive effect of the latter in terms of both seed germination rate and seedling length. At the same time, C. epichloë increased the proportion of E. typhina-untreated germinated seeds. Additionally, only the joint action of the two fungi, E. typhina and C. epichloë, effectively stimulated seedling dry mass; the presence of E. typhina alone was not sufficient to noticeably affect seedling size. Based on the increasing commonality of C. epichloë on Epichloë stromata, as well as its potential to be used in biocontrol of 'choke disease', we should take a closer look at this fungus, not only in terms of its mycoparasitic ability, but also in terms of its cumulative impact on the whole Epichloë-grass system.
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Affiliation(s)
- Karolina Górzyńska
- Department of Systematic and Environmental Botany, Adam Mickiewicz University, Poznań, Poland
| | - Paweł Olejniczak
- Institute of Nature Conservation, Polish Academy of Sciences, Kraków, Poland
| | - Ewa Węgrzyn
- Department of Systematic and Environmental Botany, Adam Mickiewicz University, Poznań, Poland
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4
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Ford RE, Foster GD, Bailey AM. Exploring fungal RiPPs from the perspective of chemical ecology. Fungal Biol Biotechnol 2022; 9:12. [PMID: 35752794 PMCID: PMC9233826 DOI: 10.1186/s40694-022-00144-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/05/2022] [Indexed: 12/31/2022] Open
Abstract
Since the initial detection, in 2007, of fungal ribosomally synthesised and post-translationally modified peptides (RiPPs), this group of natural products has undergone rapid expansion, with four separate classes now recognised: amatoxins/phallotoxins, borosins, dikaritins, and epichloëcyclins. Largely due to their historically anthropocentric employment in medicine and agriculture, novel fungal proteins and peptides are seldom investigated in relation to the fungus itself. Therefore, although the benefits these compounds confer to humans are often realised, their evolutionary advantage to the fungus, the reason for their continued production, is often obscure or ignored. This review sets out to summarise current knowledge on how these small peptide-derived products influence their producing species and surrounding biotic environment.
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Affiliation(s)
- R E Ford
- School of Biological Sciences, University of Bristol, Life Sciences Building, 28 Tyndall Ave, Bristol, BS8 1TQ, UK
| | - G D Foster
- School of Biological Sciences, University of Bristol, Life Sciences Building, 28 Tyndall Ave, Bristol, BS8 1TQ, UK
| | - A M Bailey
- School of Biological Sciences, University of Bristol, Life Sciences Building, 28 Tyndall Ave, Bristol, BS8 1TQ, UK.
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Laihonen M, Saikkonen K, Helander M, Vázquez de Aldana BR, Zabalgogeazcoa I, Fuchs B. Epichloë Endophyte-Promoted Seed Pathogen Increases Host Grass Resistance Against Insect Herbivory. Front Microbiol 2022; 12:786619. [PMID: 35087489 PMCID: PMC8787217 DOI: 10.3389/fmicb.2021.786619] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/07/2021] [Indexed: 11/13/2022] Open
Abstract
Plants host taxonomically and functionally complex communities of microbes. However, ecological studies on plant-microbe interactions rarely address the role of multiple co-occurring plant-associated microbes. Here, we contend that plant-associated microbes interact with each other and can have joint consequences for higher trophic levels. In this study we recorded the occurrence of the plant seed pathogenic fungus Claviceps purpurea and aphids (Sitobion sp.) on an established field experiment with red fescue (Festuca rubra) plants symbiotic to a seed transmitted endophytic fungus Epichloë festucae (E+) or non-symbiotic (E-). Both fungi are known to produce animal-toxic alkaloids. The study was conducted in a semi-natural setting, where E+ and E- plants from different origins (Spain and Northern Finland) were planted in a randomized design in a fenced common garden at Kevo Subarctic Research Station in Northern Finland. The results reveal that 45% of E+ plants were infected with Claviceps compared to 31% of E- plants. Uninfected plants had 4.5 times more aphids than Claviceps infected plants. By contrast, aphid infestation was unaffected by Epichloë symbiosis. Claviceps alkaloid concentrations correlated with a decrease in aphid numbers, which indicates their insect deterring features. These results show that plant mutualistic fungi can increase the infection probability of a pathogenic fungus, which then becomes beneficial to the plant by controlling herbivorous insects. Our study highlights the complexity and context dependency of species-species and multi-trophic interactions, thus challenging the labeling of species as plant mutualists or pathogens.
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Affiliation(s)
| | | | - Marjo Helander
- Department of Biology, University of Turku, Turku, Finland
| | | | - Iñigo Zabalgogeazcoa
- Institute of Natural Resources and Agrobiology of Salamanca (IRNASA-CSIC), Salamanca, Spain
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6
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Sacristán S, Goss EM, Eves-van den Akker S. How Do Pathogens Evolve Novel Virulence Activities? MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:576-586. [PMID: 33522842 DOI: 10.1094/mpmi-09-20-0258-ia] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
This article is part of the Top 10 Unanswered Questions in MPMI invited review series.We consider the state of knowledge on pathogen evolution of novel virulence activities, broadly defined as anything that increases pathogen fitness with the consequence of causing disease in either the qualitative or quantitative senses, including adaptation of pathogens to host immunity and physiology, host species, genotypes, or tissues, or the environment. The evolution of novel virulence activities as an adaptive trait is based on the selection exerted by hosts on variants that have been generated de novo or arrived from elsewhere. In addition, the biotic and abiotic environment a pathogen experiences beyond the host may influence pathogen virulence activities. We consider host-pathogen evolution, host range expansion, and external factors that can mediate pathogen evolution. We then discuss the mechanisms by which pathogens generate and recombine the genetic variation that leads to novel virulence activities, including DNA point mutation, transposable element activity, gene duplication and neofunctionalization, and genetic exchange. In summary, if there is an (epi)genetic mechanism that can create variation in the genome, it will be used by pathogens to evolve virulence factors. Our knowledge of virulence evolution has been biased by pathogen evolution in response to major gene resistance, leaving other virulence activities underexplored. Understanding the key driving forces that give rise to novel virulence activities and the integration of evolutionary concepts and methods with mechanistic research on plant-microbe interactions can help inform crop protection.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Soledad Sacristán
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo-UPM, 28223-Pozuelo de Alarcón (Madrid), Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, 28040-Madrid, Spain
| | - Erica M Goss
- Department of Plant Pathology and Emerging Pathogens Institute, University of Florida, Gainesville, Florida, U.S.A
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7
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Vikuk V, Fuchs B, Krischke M, Mueller MJ, Rueb S, Krauss J. Alkaloid Concentrations of Lolium perenne Infected with Epichloë festucae var. lolii with Different Detection Methods-A Re-Evaluation of Intoxication Risk in Germany? J Fungi (Basel) 2020; 6:jof6030177. [PMID: 32961967 PMCID: PMC7558822 DOI: 10.3390/jof6030177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/09/2020] [Accepted: 09/15/2020] [Indexed: 11/29/2022] Open
Abstract
Mycotoxins in agriculturally used plants can cause intoxication in animals and can lead to severe financial losses for farmers. The endophytic fungus Epichloë festucae var. lolii living symbiotically within the cool season grass species Lolium perenne can produce vertebrate and invertebrate toxic alkaloids. Hence, an exact quantitation of alkaloid concentrations is essential to determine intoxication risk for animals. Many studies use different methods to detect alkaloid concentrations, which complicates the comparability. In this study, we showed that alkaloid concentrations of individual plants exceeded toxicity thresholds on real world grasslands in Germany, but not on the population level. Alkaloid concentrations on five German grasslands with high alkaloid levels peaked in summer but were also below toxicity thresholds on population level. Furthermore, we showed that alkaloid concentrations follow the same seasonal trend, regardless of whether plant fresh or dry weight was used, in the field and in a common garden study. However, alkaloid concentrations were around three times higher when detected with dry weight. Finally, we showed that alkaloid concentrations can additionally be biased to different alkaloid detection methods. We highlight that toxicity risks should be analyzed using plant dry weight, but concentration trends of fresh weight are reliable.
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Affiliation(s)
- Veronika Vikuk
- Department of Animal Ecology and Tropical Biology, University of Würzburg, 97074 Würzburg, Germany; (S.R.); (J.K.)
- Correspondence:
| | - Benjamin Fuchs
- Biodiversity Unit, University of Turku, 20014 Turku, Finland;
| | - Markus Krischke
- Department of Pharmaceutical Biology, Metabolomics Core Unit, University of Würzburg, 97074 Würzburg, Germany; (M.K.); (M.J.M.)
| | - Martin J. Mueller
- Department of Pharmaceutical Biology, Metabolomics Core Unit, University of Würzburg, 97074 Würzburg, Germany; (M.K.); (M.J.M.)
| | - Selina Rueb
- Department of Animal Ecology and Tropical Biology, University of Würzburg, 97074 Würzburg, Germany; (S.R.); (J.K.)
| | - Jochen Krauss
- Department of Animal Ecology and Tropical Biology, University of Würzburg, 97074 Würzburg, Germany; (S.R.); (J.K.)
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8
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Laihonen M, Saikkonen K, Helander M, Tammaru T. Insect oviposition preference between Epichloë-symbiotic and Epichloë-free grasses does not necessarily reflect larval performance. Ecol Evol 2020; 10:7242-7249. [PMID: 32760525 PMCID: PMC7391556 DOI: 10.1002/ece3.6450] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 04/27/2020] [Accepted: 05/06/2020] [Indexed: 11/11/2022] Open
Abstract
Variation in plant communities is likely to modulate the feeding and oviposition behavior of herbivorous insects, and plant-associated microbes are largely ignored in this context. Here, we take into account that insects feeding on grasses commonly encounter systemic and vertically transmitted (via seeds) fungal Epichloë endophytes, which are regarded as defensive grass mutualists. Defensive mutualism is primarily attributable to alkaloids of fungal origin. To study the effects of Epichloë on insect behavior and performance, we selected wild tall fescue (Festuca arundinacea) and red fescue (Festuca rubra) as grass-endophyte models. The plants used either harbored the systemic endophyte (E+) or were endophyte-free (E-). As a model herbivore, we selected the Coenonympha hero butterfly feeding on grasses as larvae. We examined both oviposition and feeding preferences of the herbivore as well as larval performance in relation to the presence of Epichloë endophytes in the plants. Our findings did not clearly support the female's oviposition preference to reflect the performance of her offspring. First, the preference responses depended greatly on the grass-endophyte symbiotum. In F. arundinacea, C. hero females preferred E+ individuals in oviposition-choice tests, whereas in F. rubra, the endophytes may decrease exploitation, as both C. hero adults and larvae preferred E- grasses. Second, the endophytes had no effect on larval performance. Overall, F. arundinacea was an inferior host for C. hero larvae. However, the attraction of C. hero females to E+ may not be maladaptive if these plants constitute a favorable oviposition substrate for reasons other than the plants' nutritional quality. For example, rougher surface of E+ plant may physically facilitate the attachment of eggs, or the plants offer greater protection from natural enemies. Our results highlight the importance of considering the preference of herbivorous insects in studies involving the endophyte-symbiotic grasses as host plants.
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Affiliation(s)
| | | | | | - Toomas Tammaru
- Institute of Ecology and Earth SciencesUniversity of TartuTartuEstonia
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9
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Determination of Loline Alkaloids and Mycelial Biomass in Endophyte-Infected Schedonorus Pratensis by Near-Infrared Spectroscopy and Chemometrics. Microorganisms 2020; 8:microorganisms8050776. [PMID: 32455703 PMCID: PMC7285352 DOI: 10.3390/microorganisms8050776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 05/14/2020] [Accepted: 05/19/2020] [Indexed: 11/16/2022] Open
Abstract
Near infrared spectroscopy (NIRS) is an accurate, fast and nondestructive technique whose use in predicting forage quality has become increasingly relevant in recent decades. Epichloë-infected grass varieties are commonly used in areas with high pest pressure due to their better performances compared to endophyte-free varieties. The insect resistance of Epichloë-infected grasses has been associated with four main groups of endophyte secondary metabolites: ergot alkaloids, indole-diterpenes, lolines and peramine. Concentrations of these alkaloids are usually measured with high performance liquid chromatography or gas chromatography analysis, which are accurate methods but relatively expensive and laborious. In this paper, we developed a rapid method based on NIRS to detect and quantify loline alkaloids in wild accessions of Schedonorus pratensis infected with the fungal endophyte Epichloë uncinata. The quantitative NIR equations obtained by modified partial least squares algorithm had coefficients of correlation of 0.90, 0.78, 0.85, 0.90 for N-acetylloline, N-acetylnorloline and N-formylloline and the sum of the three, respectively. The acquired NIR spectra were also used for developing an equation to predict in planta fungal biomass with a coefficient of correlation of 0.75. These results showed that the use of NIRS and chemometrics allows the quantification of loline alkaloids and mycelial biomass in a heterogeneous set of endophyte-infected meadow fescue samples.
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10
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Krauss J, Vikuk V, Young CA, Krischke M, Mueller MJ, Baerenfaller K. Epichloë Endophyte Infection rates and Alkaloid Content in Commercially Available Grass Seed Mixtures in Europe. Microorganisms 2020; 8:microorganisms8040498. [PMID: 32244510 PMCID: PMC7232243 DOI: 10.3390/microorganisms8040498] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/17/2020] [Accepted: 03/28/2020] [Indexed: 12/04/2022] Open
Abstract
Fungal endophytes of the genus Epichloë live symbiotically in cool season grass species and can produce alkaloids toxic to insects and vertebrates, yet reports of intoxication of grazing animals have been rare in Europe in contrast to overseas. However, due to the beneficial resistance traits observed in Epichloë infected grasses, the inclusion of Epichloë in seed mixtures might become increasingly advantageous. Despite the toxicity of fungal alkaloids, European seed mixtures are rarely tested for Epichloë infection and their infection status is unknown for consumers. In this study, we tested 24 commercially available seed mixtures for their infection rates with Epichloë endophytes and measured the concentrations of the alkaloids ergovaline, lolitrem B, paxilline, and peramine. We detected Epichloë infections in six seed mixtures, and four contained vertebrate and insect toxic alkaloids typical for Epichloë festucae var. lolii infecting Lolium perenne. As Epichloë infected seed mixtures can harm livestock, when infected grasses become dominant in the seeded grasslands, we recommend seed producers to test and communicate Epichloë infection status or avoiding Epichloë infected seed mixtures.
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Affiliation(s)
- Jochen Krauss
- Department of Animal Ecology and Tropical Biology, University of Würzburg, 97074 Würzburg, Germany;
- Correspondence: ; Tel.: +49(0)931-318-2382
| | - Veronika Vikuk
- Department of Animal Ecology and Tropical Biology, University of Würzburg, 97074 Würzburg, Germany;
| | | | - Markus Krischke
- Department of Pharmaceutical Biology, Metabolomics Core Unit, University of Würzburg, 97082 Würzburg, Germany, (M.J.M.)
| | - Martin J. Mueller
- Department of Pharmaceutical Biology, Metabolomics Core Unit, University of Würzburg, 97082 Würzburg, Germany, (M.J.M.)
| | - Katja Baerenfaller
- Swiss Institute of Allergy and Asthma Research (SIAF), University of Zurich, and Swiss Institute of Bioinformatics (SIB), 7265 Davos, Switzerland;
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11
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Forester NT, Lane GA, McKenzie CM, Lamont IL, Johnson LJ. The Role of SreA-Mediated Iron Regulation in Maintaining Epichloë festucae- Lolium perenne Symbioses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:1324-1335. [PMID: 31107632 DOI: 10.1094/mpmi-03-19-0060-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In ascomycetes and basidiomycetes, iron-responsive GATA-type transcriptional repressors are involved in regulating iron homeostasis, notably to prevent iron toxicity through control of iron uptake. To date, it has been unknown whether this iron regulator contributes toward mutualistic endosymbiosis of microbes with plants, a system where the endophyte must function within the constraints of an in-host existence, including a dependency on the host for nutrient acquisition. Functional characterization of one such protein, SreA from Epichloë festucae, a fungal endosymbiont of cool-season grasses, indicates that regulation of iron homeostasis processes is important for symbiotic maintenance. The deletion of the sreA gene (ΔsreA) led to iron-dependent aberrant hyphal growth and the gradual loss of endophyte hyphae from perennial ryegrass. SreA negatively regulates the siderophore biosynthesis and high-affinity iron uptake systems of E. festucae, similar to other fungi, resulting in iron accumulation in mutants. Our evidence suggests that SreA is involved in the processes that moderate Epichloë iron acquisition from the plant apoplast, because overharvesting of iron in ΔsreA mutants was detected as premature chlorosis of the host using a hydroponic plant growth assay. E. festucae appears to have a tightly regulated iron management system, involving SreA that balances endophyte growth with its survival and prevents overcompetition with the host for iron in the intercellular niche, thus promoting mutualistic associations. Mutations that interfere with Epichloë iron management negatively affect iron-dependent fungal growth and destabilize mutualistic Epichloë -ryegrass associations.
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Affiliation(s)
- Natasha T Forester
- AgResearch Ltd., Grasslands Research Centre, Tennent Drive, Private Bag 11008, Palmerston North 4442, New Zealand
| | - Geoffrey A Lane
- AgResearch Ltd., Grasslands Research Centre, Tennent Drive, Private Bag 11008, Palmerston North 4442, New Zealand
| | - Catherine M McKenzie
- AgResearch Ltd., Grasslands Research Centre, Tennent Drive, Private Bag 11008, Palmerston North 4442, New Zealand
| | - Iain L Lamont
- Department of Biochemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Linda J Johnson
- AgResearch Ltd., Grasslands Research Centre, Tennent Drive, Private Bag 11008, Palmerston North 4442, New Zealand
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12
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Infection Rates and Alkaloid Patterns of Different Grass Species with Systemic Epichloë Endophytes. Appl Environ Microbiol 2019; 85:AEM.00465-19. [PMID: 31227553 DOI: 10.1128/aem.00465-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 06/14/2019] [Indexed: 01/05/2023] Open
Abstract
Symbiotic Epichloë species are fungal endophytes of cool-season grasses that can produce alkaloids with toxicity to vertebrates and/or invertebrates. Monitoring infections and presence of alkaloids in grasses infected with Epichloë species can provide an estimate of possible intoxication risks for livestock. We sampled 3,046 individuals of 13 different grass species in three regions on 150 study sites in Germany. We determined infection rates and used PCR to identify Epichloë species diversity based on the presence of different alkaloid biosynthesis genes, then confirmed the possible chemotypes with high-performance liquid chromatography (HPLC)/ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) measurements. Infections of Epichloë spp. were found in Festuca pratensis Huds. (81%), Festuca ovina L. aggregate (agg.) (73%), Lolium perenne L. (15%), Festuca rubra L. (15%) and Dactylis glomerata L. (8%). The other eight grass species did not appear to be infected. For the majority of Epichloë-infected L. perenne samples (98%), the alkaloids lolitrem B and peramine were present, but ergovaline was not detected, which was consistent with the genetic evaluation, as dmaW, the gene encoding the first step of the ergot alkaloid biosynthesis pathway, was absent. Epichloë uncinata in F. pratensis produced anti-insect loline compounds. The Epichloë spp. observed in the F. ovina agg. samples showed the greatest level of diversity, and different intermediates of the indole-diterpene pathway could be detected. Epichloë infection rates alone are insufficient to estimate intoxication risks for livestock, as other factors, like the ability of the endophyte to produce the alkaloids, also need to be assessed.IMPORTANCE Severe problems of livestock intoxication from Epichloë-infected forage grasses have been reported from New Zealand, Australia, and the United States, but much less frequently from Europe, and particularly not from Germany. Nevertheless, it is important to monitor infection rates and alkaloids of grasses with Epichloë fungi to estimate possible intoxication risks. Most studies focus on agricultural grass species like Lolium perenne and Festuca arundinacea, but other cool-season grass species can also be infected. We show that in Germany, infection rates and alkaloids differ between grass species and that some of the alkaloids can be toxic to livestock. Changes in grassland management due to changing climate, especially with a shift toward grasslands dominated with Epichloë-infected species such as Lolium perenne, may result in greater numbers of intoxicated livestock in the near future. We therefore suggest regular monitoring of grass species for infections and alkaloids and call for maintaining heterogenous grasslands for livestock.
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Green KA, Eaton CJ, Savoian MS, Scott B. A homologue of the fungal tetraspanin Pls1 is required for Epichloë festucae expressorium formation and establishment of a mutualistic interaction with Lolium perenne. MOLECULAR PLANT PATHOLOGY 2019; 20:961-975. [PMID: 31008572 PMCID: PMC6589725 DOI: 10.1111/mpp.12805] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Epichloë festucae is an endophytic fungus that forms a mutualistic symbiotic association with the grass host Lolium perenne. Endophytic hyphae exit the host by an appressorium-like structure known as an expressorium. In plant-pathogenic fungi, the tetraspanin Pls1 and the NADPH oxidase component Nox2 are required for appressorium development. Previously we showed that the homologue of Nox2, NoxB, is required for E. festucae expressorium development and establishment of a mutualistic symbiotic interaction with the grass host. Here we used a reverse genetics approach to functionally characterize the role of the E. festucae homologue of Pls1, PlsA. The morphology and growth of ΔplsA in axenic culture was comparable to wild-type. The tiller length of plants infected with ΔplsA was significantly reduced. Hyphae of ΔplsA had a proliferative pattern of growth within the leaves of L. perenne with increased colonization of the intercellular spaces and the vascular bundles. The ΔplsA mutant was also defective in expressorium development although the phenotype was not as severe as for ΔnoxB, highlighting potentially distinct roles for PlsA and NoxB in signalling through the NoxB complex. Hyphae of ΔplsA proliferate below the cuticle surface but still occasionally form an expressorium-like structure that enables the mutant hyphae to exit the leaf to grow on the surface. These expressoria still form a septin ring-like structure at the point of cuticle exit as found in the wild-type strain. These results establish that E. festucae PlsA has an important, but distinct, role to NoxB in expressorium development and plant symbiosis.
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Affiliation(s)
- Kimberly A. Green
- Institute of Fundamental SciencesMassey UniversityPalmerston NorthNew Zealand
| | - Carla J. Eaton
- Institute of Fundamental SciencesMassey UniversityPalmerston NorthNew Zealand
| | - Matthew S. Savoian
- Institute of Fundamental SciencesMassey UniversityPalmerston NorthNew Zealand
| | - Barry Scott
- Institute of Fundamental SciencesMassey UniversityPalmerston NorthNew Zealand
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Cagnano G, Roulund N, Jensen CS, Forte FP, Asp T, Leuchtmann A. Large Scale Screening of Epichloë Endophytes Infecting Schedonorus pratensis and Other Forage Grasses Reveals a Relation Between Microsatellite-Based Haplotypes and Loline Alkaloid Levels. FRONTIERS IN PLANT SCIENCE 2019; 10:765. [PMID: 31249582 PMCID: PMC6582706 DOI: 10.3389/fpls.2019.00765] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 05/24/2019] [Indexed: 06/09/2023]
Abstract
Species belonging to the Festuca-Lolium complex are often naturally infected with endophytic fungi of genus Epichloë. Recent studies on endophytes have shown the beneficial roles of host-endophyte associations as protection against insect herbivores in agriculturally important grasses. However, large-scale screenings are crucial to identify animal friendly strains suitable for agricultural use. In this study we analyzed collected populations of meadow fescue (Schedonorus pratensis) from 135 different locations across Europe, 255 accessions from the United States Department of Agriculture and 96 accessions from The Nordic Genetic Resource Centre. The analysis also included representatives of S. arundinaceus, S. giganteus, and Lolium perenne. All plants were screened for the presence of Epichloë endophytes, resulting in a nursery of about 2500 infected plants from 176 different locations. Genetic diversity was investigated on 250 isolates using a microsatellite-based PCR fingerprinting assay at 7 loci, 5 of which were uncharacterized for these species. Phylogenetic and principal components analysis showed a strong interspecific genetic differentiation among isolates, and, with E. uncinata isolates, a small but significant correlation between genetic diversity and geographical effect (r = 0.227) was detected. Concentrations of loline alkaloids were measured in 218 infected meadow fescue plants. Average amount of total loline and the proportions of the single loline alkaloids differed significantly among endophyte haplotypes (P < 0.005). This study provides insight into endophyte genetic diversity and geographic variation in Europe and a reference database of allele sizes for fast discrimination of isolates. We also discuss the possibility of multiple hybridization events as a source of genetic and alkaloid variation observed in E. uncinata.
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Affiliation(s)
- Giovanni Cagnano
- DLF Trifolium A/S, Roskilde, Denmark
- Department of Molecular Biology and Genetics, Faculty of Science and Technology, Research Centre Flakkebjerg, Aarhus University, Slagelse, Denmark
| | | | | | - Flavia Pilar Forte
- Department of Molecular Biology and Genetics, Faculty of Science and Technology, Research Centre Flakkebjerg, Aarhus University, Slagelse, Denmark
| | - Torben Asp
- Department of Molecular Biology and Genetics, Faculty of Science and Technology, Research Centre Flakkebjerg, Aarhus University, Slagelse, Denmark
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Moon CD, Scott B, Schardl CL, Christensen MJ. The evolutionary origins of Epichloë endophytes from annual ryegrasses. Mycologia 2019. [DOI: 10.1080/00275514.2000.12061258] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Christina D. Moon
- Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
| | - Barry Scott
- Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
| | | | - Michael J. Christensen
- AgResearch, Grasslands Research Centre, Private Bag 11008, Palmerston North, New Zealand
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Affiliation(s)
| | - Adrian Leuchtmann
- Geobotanisches Institut ETH, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
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Górzyńska K, Ślachetka M, Ryszka P, Turnau K, Płachno BJ, Lembicz M. Incidence, Identification, and Mycoparasitic Activity of Clonostachys epichloë, a Hyperparasite of the Fungal Endophyte Epichloë typhina. PLANT DISEASE 2018; 102:1973-1980. [PMID: 30088789 DOI: 10.1094/pdis-02-18-0320-re] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Fungi of the genus Epichloë (Clavicipitaceae, Ascomycota) cause choke disease in many grass species. The disease manifests itself as fungal stromata that form around developing inflorescences, thereby suppressing their maturation. Economic losses in agricultural production due to choke have long been known in the U.S.A. and France, but attempts to control choke disease have not been successful. The interaction between Epichloë typhina (Pers.) Tul. & C. Tul. and its naturally occurring fungal hyperparasite, Clonostachys epichloë (Speg.) Schroers (sexual morph Bionectria epichloë) was investigated in populations of the grass Puccinellia distans (L.) Parl. Fungal hyperparasites occur widely in nature, and many are successfully used commercially as biological control agents against plant pathogenic fungi. Microscopy of Epichloë stromata infected with C. epichloë revealed a lack of asci with ascospores in perithecia and damage to mycelia at sites colonized by C. epichloë. The ability of C. epichloë to colonize E. typhina was confirmed via two in vitro experiments. The percent inhibition of growth of E. typhina strains by C. epichloë varied from 18.40 to 46.50%, and the mycoparasite colonized up to 100% of Epichloë mycelia in a precolonization experiment. We discuss the possibility of using C. epichloë to control choke disease caused by E. typhina in grass populations.
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Affiliation(s)
- Karolina Górzyńska
- Department of Plant Taxonomy, Adam Mickiewicz University in Poznań, Poland
| | | | - Przemysław Ryszka
- Institute of Environmental Sciences, Jagiellonian University in Kraków, Poland
| | - Katarzyna Turnau
- Institute of Environmental Sciences, Jagiellonian University in Kraków, Poland
| | - Bartosz J Płachno
- Department of Plant Cytology and Embryology, Institute of Botany, Jagiellonian University in Kraków, Poland; and
| | - Marlena Lembicz
- Department of Plant Taxonomy, Adam Mickiewicz University in Poznań, Poland
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Kuldau GA, Liu JS, White JF, Siegel MR, Schardl CL. Molecular systematics of Clavicipitaceae supporting monophyly of genusEpichloëand form genusEphelis. Mycologia 2018. [DOI: 10.1080/00275514.1997.12026802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Gretchen A. Kuldau
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky 40546
| | - Jih-Shiou Liu
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky 40546
| | - James F. White
- Department of Plant Pathology, Rutgers University, New Brunswick, New Jersey 08903
| | - Malcolm R. Siegel
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky 40546
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Schulthess FM, Faeth SH. Distribution, abundances, and associations of the endophytic fungal community of Arizona fescue (Festuca arizonica). Mycologia 2018. [DOI: 10.1080/00275514.1998.12026945] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
| | - Stanley H. Faeth
- Department of Biology, Arizona State University, Tempe, Arizona 85287-1501 USA
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Contrasting roles of fungal siderophores in maintaining iron homeostasis in Epichloë festucae. Fungal Genet Biol 2018; 111:60-72. [DOI: 10.1016/j.fgb.2017.11.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 11/11/2017] [Accepted: 11/14/2017] [Indexed: 11/23/2022]
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Miwa E, Okane I, Ishiga Y, Sugawara K, Yamaoka Y. Confirmation of taxonomic status of an Epichloë species on Brachypodium sylvaticum in Japan. MYCOSCIENCE 2017. [DOI: 10.1016/j.myc.2016.12.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Moon CD, Miles CO, Järlfors U, Schardl CL. The evolutionary origins of three newNeotyphodiumendophyte species from grasses indigenous to the Southern Hemisphere. Mycologia 2017; 94:694-711. [DOI: 10.1080/15572536.2003.11833197] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Christina D. Moon
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky 40546-0091, USA
| | | | | | - Christopher L. Schardl
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky 40546-0091, USA
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Affiliation(s)
| | | | | | - Zhi-wei Wang
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
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Hoffman GD, Rao S. Fertilization of Epichloë typhina stromata by mycophagous slugs. Mycologia 2017; 106:1-7. [DOI: 10.3852/13-069] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- George D Hoffman
- Department of Crop and Soil Science, Oregon State University, Corvallis, Oregon 97331
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Karpyn Esqueda M, Yen AL, Rochfort S, Guthridge KM, Powell KS, Edwards J, Spangenberg GC. A Review of Perennial Ryegrass Endophytes and Their Potential Use in the Management of African Black Beetle in Perennial Grazing Systems in Australia. FRONTIERS IN PLANT SCIENCE 2017; 8:3. [PMID: 28154571 PMCID: PMC5244474 DOI: 10.3389/fpls.2017.00003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 01/03/2017] [Indexed: 05/05/2023]
Abstract
The major insect pest of Australian cool temperate pastures is the root-feeding insect Heteronychus arator (African black beetle, ABB). Significant pasture damage can occur even at low ABB densities (11 individuals per square meter), and often re-sowing of the whole paddock is required. Mitigation of the effects of pasture pests, and in particular subterranean species such as the larval form of ABB, can be challenging. Early detection is limited by the ability to visualize above-ground symptoms, and chemical control of insects in soil is often ineffective. This review takes a look at the historical events that molded the pastoral landscape in Australia. The importation route, changes in land management and pasture composition by European settlers may have aided the establishment of ABB in Australia. Perennial ryegrass Lolium perenne is discussed as it is one of the most important perennial agricultural grasses and is widely-sown in moderate-to-high-rainfall temperate zones of the world. Endophytic fungi from the genus Epichloë form symbiotic relationships with cool season grasses such as Lolium perenne (perennial ryegrass). They have been studied extensively and are well documented for enhancing persistence in pasture via a suite of bioactive secondary metabolites produced by the fungal symbionts. Several well-characterized secondary metabolites are discussed. Some can have negative effects on cattle (e.g., ergovaline and lolitrems) while others have been shown to benefit the host plant through deterrence of insect pests from feeding and by insecticidal activity (e.g., peramine, lolines, ergopeptines). Various control methods for ABB are also discussed, with a focus on the potential role of asexual Epichloë endophytes.
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Affiliation(s)
- Mijail Karpyn Esqueda
- AgriBio, Department of Economic Development, Jobs, Transport and Resources, Centre for AgriBioscience, Agriculture Victoria, La Trobe UniversityMelbourne, VIC, Australia
- Dairy Futures Co-operative Research CentreMelbourne, VIC, Australia
- School of Applied Systems Biology, La Trobe UniversityMelbourne, VIC, Australia
- *Correspondence: Mijail Karpyn Esqueda
| | - Alan L. Yen
- AgriBio, Department of Economic Development, Jobs, Transport and Resources, Centre for AgriBioscience, Agriculture Victoria, La Trobe UniversityMelbourne, VIC, Australia
- Dairy Futures Co-operative Research CentreMelbourne, VIC, Australia
- School of Applied Systems Biology, La Trobe UniversityMelbourne, VIC, Australia
| | - Simone Rochfort
- AgriBio, Department of Economic Development, Jobs, Transport and Resources, Centre for AgriBioscience, Agriculture Victoria, La Trobe UniversityMelbourne, VIC, Australia
- Dairy Futures Co-operative Research CentreMelbourne, VIC, Australia
- School of Applied Systems Biology, La Trobe UniversityMelbourne, VIC, Australia
- Simone Rochfort
| | - Kathryn M. Guthridge
- AgriBio, Department of Economic Development, Jobs, Transport and Resources, Centre for AgriBioscience, Agriculture Victoria, La Trobe UniversityMelbourne, VIC, Australia
- Dairy Futures Co-operative Research CentreMelbourne, VIC, Australia
| | - Kevin S. Powell
- Agriculture Victoria, Department of Economic Development, Jobs, Transport and ResourcesRutherglen, VIC, Australia
| | - Jacqueline Edwards
- AgriBio, Department of Economic Development, Jobs, Transport and Resources, Centre for AgriBioscience, Agriculture Victoria, La Trobe UniversityMelbourne, VIC, Australia
- School of Applied Systems Biology, La Trobe UniversityMelbourne, VIC, Australia
| | - German C. Spangenberg
- AgriBio, Department of Economic Development, Jobs, Transport and Resources, Centre for AgriBioscience, Agriculture Victoria, La Trobe UniversityMelbourne, VIC, Australia
- Dairy Futures Co-operative Research CentreMelbourne, VIC, Australia
- School of Applied Systems Biology, La Trobe UniversityMelbourne, VIC, Australia
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Green KA, Becker Y, Fitzsimons HL, Scott B. An Epichloë festucae homologue of MOB3, a component of the STRIPAK complex, is required for the establishment of a mutualistic symbiotic interaction with Lolium perenne. MOLECULAR PLANT PATHOLOGY 2016; 17:1480-1492. [PMID: 27277141 PMCID: PMC5132070 DOI: 10.1111/mpp.12443] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/04/2016] [Accepted: 06/06/2016] [Indexed: 05/13/2023]
Abstract
In both Sordaria macrospora and Neurospora crassa, components of the conserved STRIPAK (striatin-interacting phosphatase and kinase) complex regulate cell-cell fusion, hyphal network development and fruiting body formation. Interestingly, a number of Epichloë festucae genes that are required for hyphal cell-cell fusion, such as noxA, noxR, proA, mpkA and mkkA, are also required for the establishment of a mutualistic symbiotic interaction with Lolium perenne. To determine whether MobC, a homologue of the STRIPAK complex component MOB3 in S. macrospora and N. crassa, is required for E. festucae hyphal fusion and symbiosis, a mobC deletion strain was generated. The ΔmobC mutant showed reduced rates of hyphal cell-cell fusion, formed intrahyphal hyphae and exhibited enhanced conidiation. Plants infected with ΔmobC were severely stunted. Hyphae of ΔmobC showed a proliferative pattern of growth within the leaves of Lolium perenne with increased colonization of the intercellular spaces and vascular bundles. Although hyphae were still able to form expressoria, structures allowing the colonization of the leaf surface, the frequency of formation was significantly reduced. Collectively, these results show that the STRIPAK component MobC is required for the establishment of a mutualistic symbiotic association between E. festucae and L. perenne, and plays an accessory role in the regulation of hyphal cell-cell fusion and expressorium development in E. festucae.
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Affiliation(s)
- Kimberly A. Green
- Institute of Fundamental Sciences, Massey UniversityPalmerston North 4442New Zealand
| | - Yvonne Becker
- Institute of Fundamental Sciences, Massey UniversityPalmerston North 4442New Zealand
| | - Helen L. Fitzsimons
- Institute of Fundamental Sciences, Massey UniversityPalmerston North 4442New Zealand
| | - Barry Scott
- Institute of Fundamental Sciences, Massey UniversityPalmerston North 4442New Zealand
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Bell‐Dereske L, Gao X, Masiello CA, Sinsabaugh RL, Emery SM, Rudgers JA. Plant–fungal symbiosis affects litter decomposition during primary succession. OIKOS 2016. [DOI: 10.1111/oik.03648] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Lukas Bell‐Dereske
- Dept of Biology, MSC03‐2020 Univ. of New Mexico Albuquerque NM 87131‐0001 USA
| | - Xiaodong Gao
- Dept of Earth Science Rice Univ. Houston TX 77005 USA
| | | | | | - Sarah M. Emery
- Dept of Biology Univ. of Louisville Louisville KY 40292 USA
| | - Jennifer A. Rudgers
- Dept of Biology, MSC03‐2020 Univ. of New Mexico Albuquerque NM 87131‐0001 USA
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Fesel PH, Zuccaro A. Dissecting endophytic lifestyle along the parasitism/mutualism continuum in Arabidopsis. Curr Opin Microbiol 2016; 32:103-112. [DOI: 10.1016/j.mib.2016.05.008] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 05/10/2016] [Accepted: 05/12/2016] [Indexed: 11/17/2022]
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Saikkonen K, Young CA, Helander M, Schardl CL. Endophytic Epichloë species and their grass hosts: from evolution to applications. PLANT MOLECULAR BIOLOGY 2016; 90:665-75. [PMID: 26542393 PMCID: PMC4819788 DOI: 10.1007/s11103-015-0399-6] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/26/2015] [Indexed: 05/21/2023]
Abstract
The closely linked fitness of the Epichloë symbiont and the host grass is presumed to align the coevolution of the species towards specialization and mutually beneficial cooperation. Ecological observations demonstrating that Epichloë-grass symbioses can modulate grassland ecosystems via both above- and belowground ecosystem processes support this. In many cases the detected ecological importance of Epichloë species is directly or indirectly linked to defensive mutualism attributable to alkaloids of fungal-origin. Now, modern genetic and molecular techniques enable the precise studies on evolutionary origin of endophytic Epichloë species, their coevolution with host grasses and identification the genetic variation that explains phenotypic diversity in ecologically relevant characteristics of Epichloë-grass associations. Here we briefly review the most recent findings in these areas of research using the present knowledge of the genetic variation that explains the biosynthetic pathways driving the diversity of alkaloids produced by the endophyte. These findings underscore the importance of genetic interplay between the fungus and the host in shaping their coevolution and ecological role in both natural grass ecosystems, and in the agricultural arena.
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Affiliation(s)
- Kari Saikkonen
- Management and Production of Renewable Resources, Natural Resources Institute Finland (Luke), Itäinen Pitkäkatu 3, 20520, Turku, Finland.
| | - Carolyn A Young
- The Samuel Roberts Noble Foundation, Ardmore, OK, 73401, USA
| | - Marjo Helander
- Management and Production of Renewable Resources, Natural Resources Institute Finland (Luke), Itäinen Pitkäkatu 3, 20520, Turku, Finland
- Section of Ecology, Department of Biology, University of Turku, 20014, Turku, Finland
| | - Christopher L Schardl
- Department of Plant Pathology, University of Kentucky, Lexington, KY, 40546-0312, USA
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Hume DE, Ryan GD, Gibert A, Helander M, Mirlohi A, Sabzalian MR. Epichloë Fungal Endophytes for Grassland Ecosystems. SUSTAINABLE AGRICULTURE REVIEWS 2016. [DOI: 10.1007/978-3-319-26777-7_6] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Vandegrift R, Roy BA, Pfeifer-Meister L, Johnson BR, Bridgham SD. The herbaceous landlord: integrating the effects of symbiont consortia within a single host. PeerJ 2015; 3:e1379. [PMID: 26557442 PMCID: PMC4636405 DOI: 10.7717/peerj.1379] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 10/14/2015] [Indexed: 11/20/2022] Open
Abstract
Plants are typically infected by a consortium of internal fungal associates, including endophytes in their leaves, as well as arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) in their roots. It is logical that these organisms will interact with each other and the abiotic environment in addition to their host, but there has been little work to date examining the interactions of multiple symbionts within single plant hosts, or how the relationships among symbionts and their host change across environmental conditions. We examined the grass Agrostis capillaris in the context of a climate manipulation experiment in prairies in the Pacific Northwest, USA. Each plant was tested for presence of foliar endophytes in the genus Epichloë, and we measured percent root length colonized (PRLC) by AMF and DSE. We hypothesized that the symbionts in our system would be in competition for host resources, that the outcome of that competition could be driven by the benefit to the host, and that the host plants would be able to allocate carbon to the symbionts in such a way as to maximize fitness benefit within a particular environmental context. We found a correlation between DSE and AMF PRLC across climatic conditions; we also found a fitness cost to increasing DSE colonization, which was negated by presence of Epichloë endophytes. These results suggest that selective pressure on the host is likely to favor host/symbiont relationships that structure the community of symbionts in the most beneficial way possible for the host, not necessarily favoring the individual symbiont that is most beneficial to the host in isolation. These results highlight the need for a more integrative, systems approach to the study of host/symbiont consortia.
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Affiliation(s)
- Roo Vandegrift
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, United States
| | - Bitty A. Roy
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, United States
| | - Laurel Pfeifer-Meister
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, United States
- Environmental Science Institute, University of Oregon, Eugene, OR, United States
| | - Bart R. Johnson
- Department of Landscape Architecture, University of Oregon, Eugene, OR, United States
| | - Scott D. Bridgham
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, United States
- Environmental Science Institute, University of Oregon, Eugene, OR, United States
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Bussey RO, Kaur A, Todd DA, Egan JM, El-Elimat T, Graf TN, Raja HA, Oberlies NH, Cech NB. Comparison of the chemistry and diversity of endophytes isolated from wild-harvested and greenhouse-cultivated yerba mansa ( Anemopsis californica). PHYTOCHEMISTRY LETTERS 2015; 11:202-208. [PMID: 25642298 PMCID: PMC4307022 DOI: 10.1016/j.phytol.2014.12.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
With this study, we explored the identity and chemistry of fungal endophytes from the roots of yerba mansa [Anemopsis californica (Nutt.) Hook. & Arn. (Saururaceae)], a botanical traditionally used to treat infection. We compared the diversity of fungal endophytes isolated from a wild-harvested A. californica population, and those from plants cultivated for one year in a greenhouse environment. The wild-harvested population yielded thirteen fungal strains (eleven unique genotypes). Of the extracts prepared from these fungi, four inhibited growth of Staphylococcus aureus by >25% at 20 µg/mL, and three inhibited growth of Pseudomonas aeruginosa by ≥20% at 200 µg/mL. By comparison, A. californica roots after one year of cultivation in the greenhouse produced only two unique genotypes, neither of which displayed significant antimicrobial activity. The fungus Chaetomium cupreum isolated from wild-harvested A. californica yielded a new antimicrobial spirolactone, chaetocuprum (1). An additional fourteen known compounds were identified using LC-MS dereplication of the various fungal endophytes. This study provides new insights into the identity and chemistry of A. californica fungal endophytes, and demonstrates the importance of considering growing conditions when pursuing natural product drug discovery from endophytic fungi.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Nadja B. Cech
- Corresponding Author. ; phone 336-324-5011; fax 336-324-5402
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Vandegrift R, Blaser W, Campos-Cerda F, Heneghan AF, Carroll GC, Roy BA. Mixed fitness effects of grass endophytes modulate impact of enemy release and rapid evolution in an invasive grass. Biol Invasions 2014. [DOI: 10.1007/s10530-014-0791-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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35
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Fungal endophytes of invasive Phagramites australis populations vary in species composition and fungicide susceptibility. Symbiosis 2013. [DOI: 10.1007/s13199-013-0261-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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36
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Iannone LJ, Mc Cargo PD, Giussani LM, Schardl CL. Geographic distribution patterns of vertically transmitted endophytes in two native grasses in Argentina. Symbiosis 2012. [DOI: 10.1007/s13199-012-0214-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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37
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Karimi S, Mirlohi A, Sabzalian MR, Sayed Tabatabaei BE, Sharifnabi B. Molecular evidence for Neotyphodium fungal endophyte variation and specificity within host grass species. Mycologia 2012; 104:1281-90. [PMID: 22675051 DOI: 10.3852/11-316] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Host specificity of Neotyphodium species symbiotic with three grass species, Festuca arundinacea, Festuca pratensis and Lolium perenne, was studied based on comparisons of amplified fragment length polymorphisms (AFLP) between hosts and their corresponding endophytes. Endophytic fungi were isolated from 24 accessions of host plants. Neotyphodium identity was determined based on morphological characteristics observed in cultures and polymerase chain reaction analysis using specific primers. The results of AFLP data analysis revealed high genetic variation in plant and fungal endophyte species. Plant AFLP genotypes from different species clustered in three distinctive groups, congruent with species. A cluster analysis of AFLP data grouped endophytic isolates according to their host species and secondarily according to their host geographic distribution. The result of the AMOVA on AFLP data accounted for a large and significant proportion of genetic variation due to differences among plant and endophyte species. Phylogenetic groups of isolates corresponded to their respective host genotypes based on maximum parsimony phylograms. Comparisons of the two phylograms illustrated a significant congruence between nodes and branches of host and endophyte clades. These results strongly suggest host specificity of Neotyphodium fungal endophytes with their geographically distant host grasses within each species.
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Affiliation(s)
- Somaye Karimi
- Department of Agronomy and Plant Breeding, Isfahan University of Technology, Isfahan, Iran
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38
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Bultman TL, Leuchtmann A, Sullivan TJ, Dreyer AP. Do Botanophila flies provide reproductive isolation between two species of Epichloë fungi? A field test. THE NEW PHYTOLOGIST 2011; 190:206-212. [PMID: 21244433 DOI: 10.1111/j.1469-8137.2010.03612.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Epichloë spp., fungal endophytes of cool season grasses, produce collars of mycelium (stromata) on host stems that Botanophila flies visit for egg laying. Flies transfer fungal gametes among stromata and thereby serve to cross-fertilize fungi. Hence, the interaction is analogous to insect pollination in angiosperms. While most Epichloë species are not interfertile, Epichloë typhina and Epichloë clarkii can hybridize. We investigated whether Botanophila flies play a role in the reproductive isolation of the two Epichloë species at a field site in southwestern Switzerland. We estimated the density of stromata and collected fly larvae and stromata occurring on plants. While most ascospores collected from both species indicated intraspecific mating, 9.3% of fungal fruiting bodies contained spores of hybrid origin. Two species of Botanophila larvae occurred on stromata and both preferred E. typhina. Yet, both fly species laid eggs on both fungal species. While preferences by Botanophila flies should influence reproductive isolation between the fungi, other mechanisms are likely more important. Our data, which show hybrid ascospores are produced, suggest postzygotic isolating mechanisms are an important means of reproductive isolation.
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Affiliation(s)
| | - Adrian Leuchtmann
- Plant Ecological Genetics, Institute of Integrative Biology, ETH Zürich, Universitätstrasse 16, CH-8092 Zürich, Switzerland
| | - T J Sullivan
- Biology Department, Hope College, Holland, MI 49423, USA
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39
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Rohlfs M, Churchill ACL. Fungal secondary metabolites as modulators of interactions with insects and other arthropods. Fungal Genet Biol 2010; 48:23-34. [PMID: 20807586 DOI: 10.1016/j.fgb.2010.08.008] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 08/05/2010] [Accepted: 08/22/2010] [Indexed: 12/19/2022]
Abstract
Fungi share a diverse co-evolutionary history with animals, especially arthropods. In this review, we focus on the role of secondary metabolism in driving antagonistic arthropod-fungus interactions, i.e., where fungi serve as a food source to fungal grazers, compete with saprophagous insects, and attack insects as hosts for growth and reproduction. Although a wealth of studies on animal-fungus interactions point to a crucial role of secondary metabolites in deterring animal feeding and resisting immune defense strategies, causal evidence often remains to be provided. Moreover, it still remains an unresolved puzzle as to what extent the tight regulatory control of secondary metabolite formation in some model fungi represents an evolved chemical defense system favored by selective pressure through animal antagonists. Given these gaps in knowledge, we highlight some co-evolutionary aspects of secondary metabolism, such as induced response, volatile signaling, and experimental evolution, which may help in deciphering the ecological importance and evolutionary history of secondary metabolite production in fungi.
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Affiliation(s)
- Marko Rohlfs
- J.F. Blumenbach Institute of Zoology and Anthropology, Georg-August University of Göttingen, Germany.
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40
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Vereecken NJ, McNeil JN. Cheaters and liars: chemical mimicry at its finestThe present review is one in the special series of reviews on animal-plant interactions.In memory of Jan Tengö (1939–2010), who made exceptional contributions to our understanding of the chemical ecology of solitary bees, including chemical mimicry. CAN J ZOOL 2010. [DOI: 10.1139/z10-040] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chemical mimicry is an essential part of certain interspecific interactions, where the outcome for both species may depend on the degree to which the original signals are mimicked. In this review, we discuss a number of specific cases relating to pollination and obtaining nutrient resources that we believe exemplify recent advances in our understanding of chemical mimicry. Subsequently, we suggest avenues for future ecological and chemical research that should allow us to gain further insight into the evolution of chemical mimicry.
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Affiliation(s)
- N. J. Vereecken
- Evolutionary Biology and Ecology, Free University of Brussels/Université Libre de Bruxelles, avenue FD Roosevelt 50 CP 160/12, B-1050 Brussels, Belgium
- Department of Biology, The University of Western Ontario, London ON N6A 5B7, Canada
- Institute of Systematic Botany, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
| | - J. N. McNeil
- Evolutionary Biology and Ecology, Free University of Brussels/Université Libre de Bruxelles, avenue FD Roosevelt 50 CP 160/12, B-1050 Brussels, Belgium
- Department of Biology, The University of Western Ontario, London ON N6A 5B7, Canada
- Institute of Systematic Botany, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
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41
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Zhang X, Ren A, Ci H, Gao Y. Genetic diversity and structure of Neotyphodium species and their host Achnatherum sibiricum in a natural grass-endophyte system. MICROBIAL ECOLOGY 2010; 59:744-756. [PMID: 20352205 DOI: 10.1007/s00248-010-9652-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Accepted: 02/26/2010] [Indexed: 05/29/2023]
Abstract
Achnatherum sibiricum (Poaceae) is a perennial bunchgrass native to the Inner Mongolia Steppe of China. This grass is commonly infected by epichloë endophytes with high-infection frequencies. Previously, we identified two predominant Neotyphodium spp., N. sibiricum and N. gansuense. In the present study, genetic diversity and structure were analyzed for the two predominant Neotyphodium spp. as well as the host grass. We obtained 103 fungal isolates from five populations; 33 were identified as N. sibiricum and 61 as N. gansuense. All populations hosted both endophytic species, but genetic variation was much higher for N. gansuense than for N. sibiricum. The majority of fungal isolates were haploid, and 13% of them were heterozygous at one SSR locus, suggesting hybrid origins of those isolates. Significant linkage disequilibrium of fungal SSR loci suggested that both fungal species primarily propagate by clonal growth through plant seeds, whereas variation in genetic diversity and the presence of hybrids in both endophytic species revealed that although clonal propagation was prevalent, occasional recombination might also occur. By comparing genetic differentiation among populations, we found around 4-7-fold greater differentiation of endophyte populations than host populations, implying more restricted gene flow of endophytes than hosts. We proposed that endophyte infection of A. sibiricum might confer the host some selective advantages under certain conditions, which could help to maintain high-endophyte-infection frequencies in host populations, even when their gene flows do not match each other. Furthermore, we suggested that the same genotype of endophyte as well as host should be confirmed if the objective of the study is to know the influence of endophyte or host genotype on their symbiotic relationship, instead of just considering whether the plant is infected by an endophyte or not, since endophytes from the same host species could exhibit high levels of genetic diversity, which is likely to influence the outcome of their symbiotic relationship.
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Affiliation(s)
- Xin Zhang
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, People's Republic of China
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Hamilton CE, Faeth SH, Dowling TE. Distribution of hybrid fungal symbionts and environmental stress. MICROBIAL ECOLOGY 2009; 58:408-413. [PMID: 19290566 DOI: 10.1007/s00248-009-9504-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Accepted: 02/16/2009] [Indexed: 05/27/2023]
Abstract
Most asexual fungal symbionts of grasses in the genus Neotyphodium occurring in nature are of hybrid origin. Most hybrid Neotyphodium species result from interspecific hybridization events between pathogenic Epichloë species or co-occurring non-hybrid Neotyphodium species. Current hypotheses for the prevalence of hybrid Neotyphodium species include reduction of mutation accumulation and increased adaptive response to environmental extremes. We tested the adaptive response hypothesis by characterizing the distribution of uninfected, hybrid, and non-hybrid Neotyphodium endophytes in 24 native Arizona fescue host populations and abiotic parameters at each locality. Infection was high in all host populations (>70%), but the majority of host populations were infected by non-hybrid Neotyphodium (>50% on average). Principal component analysis indicates the frequency of plants infected with hybrid fungi is negatively related to soil nutrients and positively correlated with early spring moisture. Non-hybrid infected hosts are positively associated with soil nutrients and show a complex relationship with soil moisture (negative in early spring moisture, positive with late summer soil moisture). These results suggest the frequency of uninfected, hybrid, and non-hybrid infected plants is related to resource availability and abiotic stress factors. This supports the hypothesis that hybridization in asexual fungal symbionts increases host adaptability to extreme environments.
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Affiliation(s)
- Cyd E Hamilton
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA.
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45
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Haarmann T, Rolke Y, Giesbert S, Tudzynski P. Ergot: from witchcraft to biotechnology. MOLECULAR PLANT PATHOLOGY 2009; 10:563-77. [PMID: 19523108 PMCID: PMC6640538 DOI: 10.1111/j.1364-3703.2009.00548.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The ergot diseases of grasses, caused by members of the genus Claviceps, have had a severe impact on human history and agriculture, causing devastating epidemics. However, ergot alkaloids, the toxic components of Claviceps sclerotia, have been used intensively (and misused) as pharmaceutical drugs, and efficient biotechnological processes have been developed for their in vitro production. Molecular genetics has provided detailed insight into the genetic basis of ergot alkaloid biosynthesis and opened up perspectives for the design of new alkaloids and the improvement of production strains; it has also revealed the refined infection strategy of this biotrophic pathogen, opening up the way for better control. Nevertheless, Claviceps remains an important pathogen worldwide, and a source for potential new drugs for central nervous system diseases.
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Affiliation(s)
- Thomas Haarmann
- Institut für Botanik, Westf. Wilhelms-Universität Münster, Germany
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46
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Li C, Nan Z, Li F. Biological and physiological characteristics of Neotyphodium gansuense symbiotic with Achnatherum inebrians. Microbiol Res 2008; 163:431-40. [PMID: 16962754 DOI: 10.1016/j.micres.2006.07.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2005] [Revised: 07/19/2006] [Accepted: 07/20/2006] [Indexed: 10/24/2022]
Abstract
Biological and physiological characteristics of Neotyphodium gansuense were compared with Neotyphodium coenophialum and Epichloë festucae at a range of temperatures and pH values, and on carbon and nitrogen amended media. N. gansuense was able to grow at 10-30 degrees C, but not at 5 degrees C, and slowly at 35 degrees C. The optimal temperature for both N. gansuense and N. coenophialum was 25 degrees C, but that of E. festucae was 20-25 degrees C. The optimal pH ranges for mycelial growth of N. gansuense, N. coenophialum and E. festucae were 5-9, 5-9 and 5-7, respectively. The Neotyphodium and Epichloë endophytes varied in their ability to grow on media containing different carbon and nitrogen nutrients. The preference of N. gansuense for carbon source was sucrose>glucose, lactose, sorbitol, inulin, maltose, mannitol, starch, fructose>xylose. Growth of all three endophytes tested was significantly improved by peptone, tryptone, casein, yeast extract and l-proline. Yeast extract, peptone, casein, tryptone, l-proline, potassium nitrate, ammonium oxalic acid and l-leucine significantly improved growth of N. gansuense. However, ammonium nitrite was not utilized at all by any tested endophyte. N. gansuense grew significantly better on potato dextrose agar (PDA) and oat meal agar (OMA) than on corn meal agar (CMA) and drunken-horse-grass agar (DA), and most slowly on water agar (WA) and saltwater nutrient agar (SNA).
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Affiliation(s)
- Chunjie Li
- Key Laboratory of Grassland Agro-Ecosystem, Ministry of Agriculture, College of Pastoral Agriculture Science and Technology, Lanzhou University, Gansu Grassland Ecological Research Institute, Lanzhou, China
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Hossaert-McKey M, McKey D, Dormont L. Fungal sex as a private matter: odour signals in a specialized pollination-like insect-fungus mutualism. THE NEW PHYTOLOGIST 2008; 178:225-227. [PMID: 18371002 DOI: 10.1111/j.1469-8137.2008.02428.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Martine Hossaert-McKey
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR CNRS 5175, 1919 route de Mende, F-34293 Montpellier Cedex 5, France (*Author for correspondence: tel +33 4 67 61 32 30; fax +33 4 67 41 21 38; email )
| | - Doyle McKey
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR CNRS 5175, 1919 route de Mende, F-34293 Montpellier Cedex 5, France (*Author for correspondence: tel +33 4 67 61 32 30; fax +33 4 67 41 21 38; email )
| | - Laurent Dormont
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), UMR CNRS 5175, 1919 route de Mende, F-34293 Montpellier Cedex 5, France (*Author for correspondence: tel +33 4 67 61 32 30; fax +33 4 67 41 21 38; email )
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48
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Slippers B, Wingfield MJ. Botryosphaeriaceae as endophytes and latent pathogens of woody plants: diversity, ecology and impact. FUNGAL BIOL REV 2007. [DOI: 10.1016/j.fbr.2007.06.002] [Citation(s) in RCA: 475] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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49
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Spatafora JW, Sung GH, Sung JM, Hywel-Jones NL, White JF. Phylogenetic evidence for an animal pathogen origin of ergot and the grass endophytes. Mol Ecol 2007; 16:1701-11. [PMID: 17402984 DOI: 10.1111/j.1365-294x.2007.03225.x] [Citation(s) in RCA: 181] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Grass-associated fungi (grass symbionts) in the family Clavicipitaceae (Ascomycota, Hypocreales) are species whose host range is restricted to the plant family Poaceae and rarely Cyperaceae. The best-characterized species include Claviceps purpurea (ergot of rye) and Neotyphodium coenophialum (endophyte of tall fescue). They have been the focus of considerable research due to their importance in agricultural and grassland ecosystems and the diversity of their bioactive secondary metabolites. Here we show through multigene phylogenetic analyses and ancestral character state reconstruction that the grass symbionts in Clavicipitaceae are a derived group that originated from an animal pathogen through a dynamic process of interkingdom host jumping. The closest relatives of the grass symbionts include the genera Hypocrella, a pathogen of scale insects and white flies, and Metarhizium, a generalist arthropod pathogen. These data do not support the monophyly of Clavicipitaceae, but place it as part of a larger clade that includes Hypocreaceae, a family that contains mainly parasites of other fungi. A minimum of 5-8 independent and unidirectional interkingdom host jumps has occurred among clavicipitaceous fungi, including 3-5 to fungi, 1-2 to animals, and 1 to plants. These findings provide a new evolutionary context for studying the biology of the grass symbionts, their role in plant ecology, and the evolution of host affiliation in fungal symbioses.
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Affiliation(s)
- J W Spatafora
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA.
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50
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Cox RJ. Polyketides, proteins and genes in fungi: programmed nano-machines begin to reveal their secrets. Org Biomol Chem 2007; 5:2010-26. [PMID: 17581644 DOI: 10.1039/b704420h] [Citation(s) in RCA: 352] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fungi produce a wide variety of biologically active compounds. Among these, the polyketides form a large and structurally diverse group. These compounds are synthesised by highly programmed and very large iterative multifunctional proteins, the polyketide synthases, with nm dimensions. This review outlines the current state of knowledge regarding the links between gene sequence, protein architecture and biosynthetic programming for fungal polyketide synthases.
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Affiliation(s)
- Russell J Cox
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, UK BS8 1TS.
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