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Rétif F, Kunz C, Calabro K, Duval C, Prado S, Bailly C, Baudouin E. Seed fungal endophytes as biostimulants and biocontrol agents to improve seed performance. FRONTIERS IN PLANT SCIENCE 2023; 14:1260292. [PMID: 37941673 PMCID: PMC10628453 DOI: 10.3389/fpls.2023.1260292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 10/12/2023] [Indexed: 11/10/2023]
Abstract
Seed germination is a major determinant of plant development and final yield establishment but strongly reliant on the plant's abiotic and biotic environment. In the context of global climate change, classical approaches to improve seed germination under challenging environments through selection and use of synthetic pesticides reached their limits. A currently underexplored way is to exploit the beneficial impact of the microorganisms associated with plants. Among plant microbiota, endophytes, which are micro-organisms living inside host plant tissues without causing any visible symptoms, are promising candidates for improving plant fitness. They possibly establish a mutualistic relationship with their host, leading to enhanced plant yield and improved tolerance to abiotic threats and pathogen attacks. The current view is that such beneficial association relies on chemical mediations using the large variety of molecules produced by endophytes. In contrast to leaf and root endophytes, seed-borne fungal endophytes have been poorly studied although they constitute the early-life plant microbiota. Moreover, seed-borne fungal microbiota and its metabolites appear as a pertinent lever for seed quality improvement. This review summarizes the recent advances in the identification of seed fungal endophytes and metabolites and their benefits for seed biology, especially under stress. It also addresses the mechanisms underlying fungal effects on seed physiology and their potential use to improve crop seed performance.'
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Affiliation(s)
- Félix Rétif
- Sorbonne Université, CNRS UMR7622, Institut de Biologie Paris-Seine-Laboratoire de Biologie du Développement (IBPS-LBD), Paris, France
| | - Caroline Kunz
- Muséum National d’Histoire Naturelle, Unité Molécules de Communication et Adaptation des Micro-organismes, UMR 7245, Paris, France
- Sorbonne Université, Faculté des Sciences et Ingénierie, UFR 927, Paris, France
| | - Kevin Calabro
- Muséum National d’Histoire Naturelle, Unité Molécules de Communication et Adaptation des Micro-organismes, UMR 7245, Paris, France
| | - Clémence Duval
- Seedlab, Novalliance, Zone Anjou Actiparc, Longué-Jumelles, France
| | - Soizic Prado
- Muséum National d’Histoire Naturelle, Unité Molécules de Communication et Adaptation des Micro-organismes, UMR 7245, Paris, France
| | - Christophe Bailly
- Sorbonne Université, CNRS UMR7622, Institut de Biologie Paris-Seine-Laboratoire de Biologie du Développement (IBPS-LBD), Paris, France
| | - Emmanuel Baudouin
- Sorbonne Université, CNRS UMR7622, Institut de Biologie Paris-Seine-Laboratoire de Biologie du Développement (IBPS-LBD), Paris, France
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Beaulieu WT, Panaccione DG, Quach QN, Smoot KL, Clay K. Diversification of ergot alkaloids and heritable fungal symbionts in morning glories. Commun Biol 2021; 4:1362. [PMID: 34873267 PMCID: PMC8648897 DOI: 10.1038/s42003-021-02870-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 11/08/2021] [Indexed: 11/12/2022] Open
Abstract
Heritable microorganisms play critical roles in life cycles of many macro-organisms but their prevalence and functional roles are unknown for most plants. Bioactive ergot alkaloids produced by heritable Periglandula fungi occur in some morning glories (Convolvulaceae), similar to ergot alkaloids in grasses infected with related fungi. Ergot alkaloids have been of longstanding interest given their toxic effects, psychoactive properties, and medical applications. Here we show that ergot alkaloids are concentrated in four morning glory clades exhibiting differences in alkaloid profiles and are more prevalent in species with larger seeds than those with smaller seeds. Further, we found a phylogenetically-independent, positive correlation between seed mass and alkaloid concentrations in symbiotic species. Our findings suggest that heritable symbiosis has diversified among particular clades by vertical transmission through seeds combined with host speciation, and that ergot alkaloids are particularly beneficial to species with larger seeds. Our results are consistent with the defensive symbiosis hypothesis where bioactive ergot alkaloids from Periglandula symbionts protect seeds and seedlings from natural enemies, and provide a framework for exploring microbial chemistry in other plant-microbe interactions.
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Affiliation(s)
- Wesley T Beaulieu
- Department of Biology, Indiana University, Bloomington, IN, USA
- Jaeb Center for Health Research, Tampa, FL, USA
| | - Daniel G Panaccione
- Division of Plant & Soil Sciences, West Virginia University, Morgantown, WV, USA
| | - Quynh N Quach
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA
| | - Katy L Smoot
- Division of Plant & Soil Sciences, West Virginia University, Morgantown, WV, USA
| | - Keith Clay
- Department of Biology, Indiana University, Bloomington, IN, USA.
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA.
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Bioprospecting Desert Plants for Endophytic and Biostimulant Microbes: A Strategy for Enhancing Agricultural Production in a Hotter, Drier Future. BIOLOGY 2021; 10:biology10100961. [PMID: 34681060 PMCID: PMC8533330 DOI: 10.3390/biology10100961] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/18/2021] [Accepted: 09/21/2021] [Indexed: 01/14/2023]
Abstract
Simple Summary Endophytes are microbes that live inside plants without causing negative effects in their hosts. All land plants are known to have endophytes, and these endophytes have the capacity to be transferred between plants. Taking endophytes from desert plants, which grow in low-nutrient, high-stress environments, and transferring them to crop plants may alleviate some of the challenges being faced by the agricultural industry, such as increasing drought frequency and rising opposition to chemical use in agriculture. Studies have shown that desert endophytes have the capacity to increase nutrient uptake and increase plant resistance to drought and heat stress, salt stress, and pathogen attack. Currently, the agricultural industry focuses on using irrigation, chemical fertilizers, and chemical pesticides to solve such issues, which can be extremely damaging to the environment. While there is still a lot that is unknown about endophytes, particularly desert plant endophytes, current research provides evidence that desert plant endophytes could be an environmentally friendly alternative to the conventional solutions being applied today. Abstract Deserts are challenging places for plants to survive in due to low nutrient availability, drought and heat stress, water stress, and herbivory. Endophytes—microbes that colonize and infect plant tissues without causing apparent disease—may contribute to plant success in such harsh environments. Current knowledge of desert plant endophytes is limited, but studies performed so far reveal that they can improve host nutrient acquisition, increase host tolerance to abiotic stresses, and increase host resistance to biotic stresses. When considered in combination with their broad host range and high colonization rate, there is great potential for desert endophytes to be used in a commercial agricultural setting, especially as croplands face more frequent and severe droughts due to climate change and as the agricultural industry faces mounting pressure to break away from agrochemicals towards more environmentally friendly alternatives. Much is still unknown about desert endophytes, but future studies may prove fruitful for the discovery of new endophyte-based biofertilizers, biocontrol agents, and abiotic stress relievers of crops.
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Pérez LI, Gundel PE, Zabalgogeazcoa I, Omacini M. An ecological framework for understanding the roles of Epichloë endophytes on plant defenses against fungal diseases. FUNGAL BIOL REV 2020. [DOI: 10.1016/j.fbr.2020.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Pereira H, Detrain C. Prophylactic Avoidance of Hazardous Prey by the Ant Host Myrmica rubra. INSECTS 2020; 11:E444. [PMID: 32674516 PMCID: PMC7412340 DOI: 10.3390/insects11070444] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/03/2020] [Accepted: 07/10/2020] [Indexed: 12/13/2022]
Abstract
Ants are the hosts of many microorganisms, including pathogens that are incidentally brought inside the nest by foragers. This is particularly true for scavenging species, which collect hazardous food such as dead insects. Foragers limit sanitary risks by not retrieving highly infectious prey releasing entomopathogenic fungal spores. This study investigates whether similar prophylactic strategies are also developed for food associated with weak or delayed risks of fungal contamination. We compared, in Myrmica rubra ant colonies, the retrieval dynamics of dead flies that were (1) conidia-free, (2) covered with a low amount of Metarhizium brunneum entomopathogenic conidia or (3) recently fungus-killed but not yet sporulating. Foragers mostly avoided fungus-killed prey and delayed the retrieval of conidia-covered flies. A second sanitary filter occurred inside the nest through a careful inspection of the retrieved prey. Ultimately, ants mostly consumed conidia-free and conidia-covered flies, but they relocated and discarded all fungus-killed prey outside of the nest. Our study confirms that, as a host of generalist entomopathogenic fungi, Myrmica rubra ants have developed a prophylactic avoidance and a differential management of prey depending on their infectious potential. We discuss the functional value as well as the possible cues underlying pathogen avoidance and prey discrimination in ants.
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Affiliation(s)
- Hugo Pereira
- Unit of Social Ecology, CP 231, Université Libre de Bruxelles, Boulevard du Triomphe, 1050 Brussels, Belgium;
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Freitas PP, Hampton JG, Rolston MP, Glare TR, Miller PP, Card SD. A Tale of Two Grass Species: Temperature Affects the Symbiosis of a Mutualistic Epichloë Endophyte in Both Tall Fescue and Perennial Ryegrass. FRONTIERS IN PLANT SCIENCE 2020; 11:530. [PMID: 32457777 PMCID: PMC7225326 DOI: 10.3389/fpls.2020.00530] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 04/07/2020] [Indexed: 05/12/2023]
Abstract
Many cool-season grasses form permanent, mutualistic symbioses with asexual Epichloë endophytes. These fungal symbionts often perform a protective role within the association as many strains produce secondary metabolites that deter certain mammalian and invertebrate herbivores. Although initially a serious issue for agriculture, due to mammalian toxins that manifested in major animal health issues, selected strains that provide abiotic stress protection to plants with minimal ill effects to livestock are now commercialized and routinely used to enhance pasture performance in many farming systems. These fungal endophytes and their grass hosts have coevolved over millions of years, and it is now generally accepted that most taxonomic groupings of Epichloë are confined to forming compatible associations (i.e., symptomless associations) with related grass genera within a tribe. The most desired compounds associated with Epichloë festucae var. lolii, an endophyte species associated with perennial ryegrass, are peramine and epoxy-janthitrems. No other major secondary metabolites with invertebrate bioactivity have been identified within this association. However, other agriculturally beneficial compounds, such as lolines, have been discovered in related endophyte species that form associations with fescue grasses. A rationale therefore existed to develop novel grass-endophyte associations between loline-producing endophytes originally isolated from tall fescue with elite cultivars of perennial ryegrass to achieve a wider spectrum of insect bioactivity. A suitable loline-producing endophyte strain of Epichloë sp. FaTG-3 was selected and inoculated into perennial ryegrass. We hypothesed that endophyte transmission frequency, endophyte mycelial biomass and endophyte-derived alkaloid production would differ between the original tall fescue host and the artificial association. Consistent with our hypothesis, our data strongly suggest that plant species significantly affected the plant-endophyte association. This effect became more apparent for transmission frequency and endophyte biomass as the plants matured. Overall, the viable endophyte infection frequency was greater in the tall fescue host than in perennial ryegrass, at all sampling dates. Additionally, temperature was found to be a significant factor affecting endophyte transmission frequency, endophyte mycelial biomass and alkaloid production. Implications for the development of novel grass-endophyte associations are discussed.
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Affiliation(s)
| | - John G. Hampton
- Bio-Protection Research Centre, Lincoln University, Lincoln, New Zealand
| | - M. Phil. Rolston
- Forage Science, AgResearch Limited, Lincoln Research Centre, Lincoln, New Zealand
- The Foundation for Arable Research, Christchurch, New Zealand
| | - Travis R. Glare
- Bio-Protection Research Centre, Lincoln University, Lincoln, New Zealand
| | - Poppy P. Miller
- Knowledge and Analytics, AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand
| | - Stuart D. Card
- Forage Science, AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand
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Hewitt KG, Mace WJ, McKenzie CM, Matthew C, Popay AJ. Fungal Alkaloid Occurrence in Endophyte-Infected Perennial Ryegrass during Seedling Establishment. J Chem Ecol 2020; 46:410-421. [PMID: 32125583 DOI: 10.1007/s10886-020-01162-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/06/2020] [Accepted: 02/18/2020] [Indexed: 10/24/2022]
Abstract
The symbiotic Epichloë festucae var. lolii endophyte produces alkaloids which can provide its host grass, perennial ryegrass (Lolium perenne L), with a selective advantage in both natural and agricultural managed ecosystems. This study focuses on understanding the alkaloid concentrations that occur in endophyte-infected perennial ryegrass during the early establishment phase. In a glasshouse experiment fungal alkaloid concentrations (peramine, lolitrem B, ergovaline, and epoxy-janthitrems) were measured in perennial ryegrass seedlings infected with E. festucae var. lolii proprietary strains AR1, AR37, NEA2, and NZ common toxic for 69 days after sowing. The endophyte becomes metabolically active, starting alkaloid production, as early as 6 days after sowing. Alkaloid concentrations peaked in 8- to 10- day-old seedlings due to a seedling growth slowdown. This study provides data showing that the loss of insect protection in endophyte-infected seedlings is linked to a reduction in chemical defence after seed-stored, maternally synthesised alkaloids are diluted by seedling dry matter accumulation.
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Affiliation(s)
- Katrin G Hewitt
- The New Zealand Institute for Plant and Food Research Limited (Plant & Food Research), Physiological Chemistry, Ruakura, Private Bag 3230, Waikato Mail Centre, Hamilton, 3240, New Zealand. .,AgResearch Ltd, Biocontrol & Biosecurity, Grasslands Research Centre, Private Bag 11008, Palmerston North, 4442, New Zealand.
| | - Wade J Mace
- AgResearch Ltd, Forage Improvement, Grasslands Research Centre, Private Bag 11008, Palmerston North, 4442, New Zealand
| | - Catherine M McKenzie
- Plant & Food Research, Data Science, 412 No 1 Road, RD 2, Te Puke, 3182, New Zealand
| | - Cory Matthew
- School of Agriculture and Environment, Massey University, Private Bag 11-222, Palmerston North, 4442, New Zealand
| | - Alison J Popay
- AgResearch Ltd, Biocontrol & Biosecurity, Ruakura Research Private Bag 3123, Hamilton, 3240, New Zealand
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9
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Xia C, Li N, Zhang Y, Li C, Zhang X, Nan Z. Role of Epichloë Endophytes in Defense Responses of Cool-Season Grasses to Pathogens: A Review. PLANT DISEASE 2018; 102:2061-2073. [PMID: 30270751 DOI: 10.1094/pdis-05-18-0762-fe] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Various cool-season grasses are infected by Epichloë endophyte, and this symbiotic relationship is always of benefit to the host grass due to an increased resistance to abiotic and biotic stresses. Fungal diseases adversely affect the yield, quality, and economic benefits of rangelands, which affects the production of animal husbandry. Therefore, it is imperative to breed resistant cultivars and to better understand the role of fungal endophytes in order to protect grasses against pathogens. The present review introduces research regarding how these endophytes affect the growth of pathogens in vitro and how they change the resistance of host plants to plant diseases. From the perspective of physical defense, changes in physiological indexes, and secretion of chemical compounds, we summarize the potential mechanisms by which endophytes are able to enhance the disease resistance of a host grass. Through these, we aim to establish a solid theoretical foundation for plant disease control and disease resistance breeding by application of fungal endophytes. A broader understanding of fungal endophyte effects on hosts could create a new opportunity for managing or introducing fungal symbioses in both agronomic or non-agronomic ecosystems.
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Affiliation(s)
- Chao Xia
- State Key Laboratory of Grassland Agro-Ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture; and College of Pastoral Agricultural Science and Technology, Lanzhou University, P. O. Box 61, Lanzhou 730020, P. R. China
| | - Nana Li
- State Key Laboratory of Grassland Agro-Ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture; and College of Pastoral Agricultural Science and Technology, Lanzhou University, P. O. Box 61, Lanzhou 730020, P. R. China
| | - Yawen Zhang
- State Key Laboratory of Grassland Agro-Ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture; and College of Pastoral Agricultural Science and Technology, Lanzhou University, P. O. Box 61, Lanzhou 730020, P. R. China
| | - Chunjie Li
- State Key Laboratory of Grassland Agro-Ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture; and College of Pastoral Agricultural Science and Technology, Lanzhou University, P. O. Box 61, Lanzhou 730020, P. R. China
| | - Xingxu Zhang
- State Key Laboratory of Grassland Agro-Ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture; and College of Pastoral Agricultural Science and Technology, Lanzhou University, P. O. Box 61, Lanzhou 730020, P. R. China
| | - Zhibiao Nan
- State Key Laboratory of Grassland Agro-Ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture; and College of Pastoral Agricultural Science and Technology, Lanzhou University, P. O. Box 61, Lanzhou 730020, P. R. China
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Bamisile BS, Dash CK, Akutse KS, Keppanan R, Wang L. Fungal Endophytes: Beyond Herbivore Management. Front Microbiol 2018; 9:544. [PMID: 29628919 PMCID: PMC5876286 DOI: 10.3389/fmicb.2018.00544] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 03/09/2018] [Indexed: 11/13/2022] Open
Abstract
The incorporation of entomopathogenic fungi as biocontrol agents into Integrated Pest Management (IPM) programs without doubt, has been highly effective. The ability of these fungal pathogens such as Beauveria bassiana and Metarhizium anisopliae to exist as endophytes in plants and protect their colonized host plants against the primary herbivore pests has widely been reported. Aside this sole role of pest management that has been traditionally ascribed to fungal endophytes, recent findings provided evidence of other possible functions as plant yield promoter, soil nutrient distributor, abiotic stress and drought tolerance enhancer in plants. However, reports on these additional important effects of fungal endophytes on the colonized plants remain scanty. In this review, we discussed the various beneficial effects of endophytic fungi on the host plants and their primary herbivore pests; as well as some negative effects that are relatively unknown. We also highlighted the prospects of our findings in further increasing the acceptance of fungal endophytes as an integral part of pest management programs for optimized crop production.
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Affiliation(s)
- Bamisope S. Bamisile
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management for Fujian and Taiwan Crops, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Chandra K. Dash
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management for Fujian and Taiwan Crops, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
- Department of Entomology, Faculty of Agriculture, Sylhet Agricultural University, Sylhet, Bangladesh
| | - Komivi S. Akutse
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Ravindran Keppanan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management for Fujian and Taiwan Crops, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Liande Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
- College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Integrated Pest Management for Fujian and Taiwan Crops, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
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Shaffer JP, Sarmiento C, Zalamea PC, Gallery RE, Davis AS, Baltrus DA, Arnold AE. Diversity, Specificity, and Phylogenetic Relationships of Endohyphal Bacteria in Fungi That Inhabit Tropical Seeds and Leaves. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00116] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Bao G, Saikkonen K, Wang H, Zhou L, Chen S, Li C, Nan Z. Does endophyte symbiosis resist allelopathic effects of an invasive plant in degraded grassland? FUNGAL ECOL 2015. [DOI: 10.1016/j.funeco.2015.05.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Friesen ML, Porter SS, Stark SC, von Wettberg EJ, Sachs JL, Martinez-Romero E. Microbially Mediated Plant Functional Traits. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2011. [DOI: 10.1146/annurev-ecolsys-102710-145039] [Citation(s) in RCA: 357] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Maren L. Friesen
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089;
| | - Stephanie S. Porter
- Center for Population Biology, University of California, Davis, California 95616
| | - Scott C. Stark
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85721
| | - Eric J. von Wettberg
- Department of Biological Sciences, Florida International University, Miami, Florida 33199
- Center for Tropical Plant Conservation, Fairchild Tropical Botanical Garden, Coral Gables, Florida 33156
| | - Joel L. Sachs
- Department of Biology, University of California, Riverside, California 92521
| | - Esperanza Martinez-Romero
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de Mexico, Cuernavaca, Morelos 62210 Mexico
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González V, Tello ML. The endophytic mycota associated with Vitis vinifera in central Spain. FUNGAL DIVERS 2010. [DOI: 10.1007/s13225-010-0073-x] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Saari S, Helander M, Faeth SH, Saikkonen K. The effects of endophytes on seed production and seed predation of tall fescue and meadow fescue. MICROBIAL ECOLOGY 2010; 60:928-934. [PMID: 20871988 DOI: 10.1007/s00248-010-9749-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 09/12/2010] [Indexed: 05/29/2023]
Abstract
Fungal endophytes of grasses are often included in agricultural management and in ecological studies of natural grass populations. In European agriculture and ecological studies, however, grass endophytes are largely ignored. In this study, we determined endophyte infection frequencies of 13 European cultivars and 49 wild tall fescue (Schedonorus phoenix) populations in Northern Europe. We then examined seed production and seed predation of endophyte-infected (E+) and endophyte-free (E-) tall fescue (in wild grass populations and in a field experiment) and meadow fescue (Schedonorus pratensis; in a field experiment only). Endophytes were detected in only one of the 13 cultivars. In contrast, >90% of wild tall fescue plants harbored endophytes in 45 wild populations but were absent in three inland populations in Estonia. In three wild tall fescue study sites, 17%, 22%, and 56% of the seeds were preyed upon by the cocksfoot moth. Endophyte infection did not affect seed mass of tall fescue in the field experiment. However, seed predation was lower in E+ than E- grasses in the two tall fescue populations with higher predation rates. For meadow fescue, the mean number of seeds from E+ plants was higher than E- plants, but E- and E+ seeds had equal rates of predation by the moth. Our results suggest that the effects of grass endophytes on seed production and cocksfoot moth seed predation vary considerably among grass species, and the effects may depend on herbivore pressure and other environmental conditions.
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Affiliation(s)
- Susanna Saari
- Biology Department, The University of North Carolina at Greensboro, Greensboro, NC, USA.
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Nicolai N, Feagin RA, Smeins FE. Spatial patterns of grass seedling recruitment imply predation and facilitation by harvester ants. ENVIRONMENTAL ENTOMOLOGY 2010; 39:127-133. [PMID: 20146848 DOI: 10.1603/en09166] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Extended drought on the Edwards Plateau, TX, causes high mortality in grass species' populations and their replacement by recruitment from the seeds of survivors. Harvester ant nests may act as refugia for perennial plants during drought, as evidenced by a high survivorship of plants directly adjacent to nests. Because grasses tend to disperse seeds short distances and drought eliminated seed banks, we hypothesized that the spatial pattern of grass seedlings and adults would be clumped at small scales around these refugia. In contrast, nests would be regular at small to moderate scales. We studied the spatial patterns of seedlings, adults, and ant nest locations using a modified Ripley's K-function technique for transect data. Point data were collected along a 1-km transect. Spatially regular patterns were found for nests from 1.0- to 22.0-m scales. We found that two species' seedlings and adults were significantly clumped with ant nests, and two species had significantly regular spatial patterns with nests. Surprisingly, patterns of clumped seedlings occurred up to 30-m scales with nests. Nests appear to affect seedling establishment at multiple scales. These results suggest that nests may facilitate colonization for some grass populations, but regular spatial patterns in other species imply that forager seed harvest may inhibit establishment.
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Affiliation(s)
- N Nicolai
- Department of Ecosystem Science and Management, Texas A&M University, College Station, TX 77810, USA.
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Preferential removal of non-injured seeds by an omnivorous ant, Tetramorium tsushimae Emery, in the seed dispersal of Chamaesyce maculata (L.) small. Ecol Res 2009. [DOI: 10.1007/s11284-009-0593-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Mechanical defence in seeds to avoid predation by a granivorous ant. Naturwissenschaften 2008; 95:501-6. [PMID: 18288470 DOI: 10.1007/s00114-008-0349-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Revised: 09/14/2007] [Accepted: 01/23/2008] [Indexed: 10/22/2022]
Abstract
Harvester ants have traditionally been considered as seed predators that negatively affect plants. In some cases, however, they can also act as positive seed dispersers. During field observations, we noted that a portion of Psoralea bituminosa seeds that were collected and carried to the nest by the granivorous harvester ant Messor barbarus were discarded intact in refuse piles outside the nest. We analyzed and compared the physical characteristics of size, mass and toughness in P. bituminosa seeds from two different origins: intact seeds found in the ant's refuse piles and seeds collected directly from the plants. Seeds from refuse piles were similar in width but lighter and tougher than seeds from the plant. Our results point to a mechanical defence based on seed toughness to avoid predation by M. barbarus and suggest that an elevated proportion (approximately 69%) of the seeds produced by P. bituminosa could be too tough to be consumed by this ant. These transported but uneaten seeds could benefit by being moved far from the mother plant and this could act as a selective evolutionary pressure towards tough seeds.
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Faeth SH, Hamilton CE. Does an asexual endophyte symbiont alter life stage and long-term survival in a perennial host grass? MICROBIAL ECOLOGY 2006; 52:748-55. [PMID: 16944342 DOI: 10.1007/s00248-006-9123-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2006] [Accepted: 06/06/2006] [Indexed: 05/11/2023]
Abstract
Asexual, seedborne endophytic fungi in perennial grasses are often viewed as strong mutualists because fitness of the symbiont and host grass are closely coupled. However, at least for some native grasses, the asexual endophyte, Neotyphodium, acts parasitically, yet remains at high frequencies in natural populations. Most previous studies of Neotyphodium effects on host survival have been short term relative to the long life span of the perennial grass host. We therefore tested the hypothesis that Neotyphodium alters the survival in various life stages and long-term survival of adult native Arizona fescue (Festuca arizonica). To test the former, we planted 40 infected (E+) and 40 uninfected (E-, endophyte removed) seeds from four different maternal plants in the field under ambient conditions. We followed survival of seeds, seedlings, and adult plants over a 5-year period. To test the latter, we determined the infection of 1633 adult plants and followed their survival over the next 5-7 years. E+ seeds did not differ from uninfected seeds in terms of overall survival from seed germination to seedling to adult. However, the shape of the survival curve differed, with E+ plants showing higher mortality in early life stages. E+ adult plants did not differ from E- plants in long-term survival. Survival was generally very high during the study, which included a severe and prolonged drought. Infection by asexual Neotyphodium does not increase survival in early life stages or that of adult plants. Because asexual, vertically transmitted symbionts are predicted by evolutionary theory to be strong mutualists, the persistence of high infection frequencies in natural populations without long-term benefits to the host remains enigmatic. One possible explanation is that the long life span of the perennial host and low seedling recruitment may obscure either the costs or benefits of endophyte infection.
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Affiliation(s)
- Stanley H Faeth
- School of Life Sciences, Arizona State University, PO BOX 874501, Tempe, AZ 85287-4501, USA.
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White J, Bischoff J. Evolutionary Development of the Clavicipitaceae. Mycology 2005. [DOI: 10.1201/9781420027891.ch25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Faeth SH, Helander ML, Saikkonen KT. Asexual Neotyphodium endophytes in a native grass reduce competitive abilities. Ecol Lett 2004. [DOI: 10.1111/j.1461-0248.2004.00578.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Sullivan TJ, Faeth SH. Gene flow in the endophyte Neotyphodium and implications for coevolution with Festuca arizonica. Mol Ecol 2004; 13:649-56. [PMID: 14871368 DOI: 10.1046/j.1365-294x.2004.02091.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Arizona fescue (Festuca arizonica) often harbours asymptomatic, asexual endophytic fungi from the genus Neotyphodium. In agronomic grasses, Neotyphodium endophytes are often credited with a wide range of mutualistic benefits to its host many of which are related to fungal production of alkaloids for herbivore deterrence. Neotyphodium in the native grass Arizona fescue, however, usually produces alkaloids at levels too low to deter herbivores, and in general, does not behave mutualistically. This study uses microsatellite markers to examine rates of gene flow among four Arizona populations of Neotyphodium. Haplotypic diversity was generally low; only one population contained more than two haplotypes. Haplotypes carrying multiple loci for some or all of the microsatellite loci were also found, indicating a vegetative hybridization event between Neotyphodium and the grass choke pathogen from the genus Epichloë. Gene flow between Neotyphodium populations is very low, and likely much lower than the pollen mediated gene flow of its host. These differing rates of gene flow are predicted to create trait mismatching between endophyte and host and may explain the low, or lack of, alkaloid production by Neotyphodium in Arizona fescue and other native grass species.
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Affiliation(s)
- T J Sullivan
- School of Life Sciences, Arizona State University, Tempe AZ 85283-1501, USA.
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Clay K, Schardl C. Evolutionary Origins and Ecological Consequences of Endophyte Symbiosis with Grasses. Am Nat 2002; 160 Suppl 4:S99-S127. [DOI: 10.1086/342161] [Citation(s) in RCA: 705] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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MacMahon JA, Mull JF, Crist TO. Harvester Ants (Pogonomyrmexspp.): Their Community and Ecosystem Influences. ACTA ACUST UNITED AC 2000. [DOI: 10.1146/annurev.ecolsys.31.1.265] [Citation(s) in RCA: 211] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- James A. MacMahon
- Department of Biology and Ecology Center, Utah State University, Logan, Utah 84322; e-mail:
- Department of Zoology, Weber State University, Ogden, Utah 84408; e-mail:
- Department of Zoology, Miami University, Oxford, OH 45056; e-mail:
| | - John F. Mull
- Department of Biology and Ecology Center, Utah State University, Logan, Utah 84322; e-mail:
- Department of Zoology, Weber State University, Ogden, Utah 84408; e-mail:
- Department of Zoology, Miami University, Oxford, OH 45056; e-mail:
| | - Thomas O. Crist
- Department of Biology and Ecology Center, Utah State University, Logan, Utah 84322; e-mail:
- Department of Zoology, Weber State University, Ogden, Utah 84408; e-mail:
- Department of Zoology, Miami University, Oxford, OH 45056; e-mail:
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Saikkonen K, Faeth SH, Helander M, Sullivan TJ. FUNGAL ENDOPHYTES: A Continuum of Interactions with Host Plants. ACTA ACUST UNITED AC 1998. [DOI: 10.1146/annurev.ecolsys.29.1.319] [Citation(s) in RCA: 714] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- K. Saikkonen
- Department of Biology, University of Turku, Turku, FIN-20014 Finland
- Department of Biology, Arizona State University, Tempe, Arizona 85287-1501; e-mail:
| | - S. H. Faeth
- Department of Biology, University of Turku, Turku, FIN-20014 Finland
- Department of Biology, Arizona State University, Tempe, Arizona 85287-1501; e-mail:
| | - M. Helander
- Department of Biology, University of Turku, Turku, FIN-20014 Finland
- Department of Biology, Arizona State University, Tempe, Arizona 85287-1501; e-mail:
| | - T. J. Sullivan
- Department of Biology, University of Turku, Turku, FIN-20014 Finland
- Department of Biology, Arizona State University, Tempe, Arizona 85287-1501; e-mail:
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