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Mwangi NG, Stevens M, Wright AJD, Edwards SG, Hare MC, Back MA. Grass-Endophyte Interactions and Their Associated Alkaloids as a Potential Management Strategy for Plant Parasitic Nematodes. Toxins (Basel) 2024; 16:274. [PMID: 38922168 PMCID: PMC11209465 DOI: 10.3390/toxins16060274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 05/29/2024] [Accepted: 06/13/2024] [Indexed: 06/27/2024] Open
Abstract
Claviceptaceous endophytic fungi in the genus Epichloë mostly form a symbiotic relationship with cool-season grasses. Epichloë spp. are capable of producing bioactive alkaloids such as peramines, lolines, ergot alkaloids, and indole-diterpenes, which protect the host plant from herbivory by animals, insects, and nematodes. The host also benefits from enhanced tolerance to abiotic stresses, such as salt, drought, waterlogging, cold, heavy metals, and low nitrogen stress. The bioactive alkaloids produced can have both direct and indirect effects towards plant parasitic nematodes. Direct interaction with nematodes' motile stages can cause paralysis (nematostatic effect) or death (nematicidal effect). Indirectly, the metabolites may induce host immunity which inhibits feeding and subsequent nematode development. This review highlights the different mechanisms through which this interaction and the metabolites produced have been explored in the suppression of plant parasitic nematodes and also how the specific interactions between different grass genotypes and endophyte strains result in variable suppression of different nematode species. An understanding of the different grass-endophyte interactions and their successes and failures in suppressing various nematode species is essential to enable the proper selection of grass-endophyte combinations to identify the alkaloids produced, concentrations required, and determine which nematodes are sensitive to which specific alkaloids.
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Affiliation(s)
- Nyambura G. Mwangi
- Agriculture and Environment Department, Harper Adams University, Newport TF10 8NB, UK; (S.G.E.); (M.C.H.); (M.A.B.)
| | - Mark Stevens
- British Beet Research Organisation, Centrum, Norwich Research Park, Colney Lane, Norwich NR4 7UG, UK; (M.S.); (A.J.D.W.)
| | - Alistair J. D. Wright
- British Beet Research Organisation, Centrum, Norwich Research Park, Colney Lane, Norwich NR4 7UG, UK; (M.S.); (A.J.D.W.)
| | - Simon G. Edwards
- Agriculture and Environment Department, Harper Adams University, Newport TF10 8NB, UK; (S.G.E.); (M.C.H.); (M.A.B.)
| | - Martin C. Hare
- Agriculture and Environment Department, Harper Adams University, Newport TF10 8NB, UK; (S.G.E.); (M.C.H.); (M.A.B.)
| | - Matthew A. Back
- Agriculture and Environment Department, Harper Adams University, Newport TF10 8NB, UK; (S.G.E.); (M.C.H.); (M.A.B.)
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Oono R, Chou V, Irving M. How do phytophagous insects affect phyllosphere fungi? Tracking fungi from milkweed to monarch caterpillar frass reveals communities dominated by fungal yeast. ENVIRONMENTAL MICROBIOLOGY REPORTS 2024; 16:e13213. [PMID: 38738810 PMCID: PMC11089944 DOI: 10.1111/1758-2229.13213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 10/26/2023] [Indexed: 05/14/2024]
Abstract
Since a significant proportion of plant matter is consumed by herbivores, a necessary adaptation for many phyllosphere microbes could be to survive through the guts of herbivores. While many studies explore the gut microbiome of herbivores by surveying the microbiome in their frass, few studies compare the phyllosphere microbiome to the gut microbiome of herbivores. High-throughput metabarcode sequencing was used to track the fungal community from milkweed (Asclepias spp.) leaves to monarch caterpillar frass. The most commonly identified fungal taxa that dominated the caterpillar frass after the consumption of leaves were yeasts, mostly belonging to the Basidiomycota phylum. While most fungal communities underwent significant bottlenecks and some yeast taxa increased in relative abundance, a consistent directional change in community structure was not identified from leaf to caterpillar frass. These results suggest that some phyllosphere fungi, especially diverse yeasts, can survive herbivory, but whether herbivory is a key stage of their life cycle remains uncertain. For exploring phyllosphere fungi and the potential coprophilous lifestyles of endophytic and epiphytic fungi, methods that target yeast and Basidiomycota fungi are recommended.
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Affiliation(s)
- Ryoko Oono
- Department of Ecology, Evolution, and Marine BiologyUniversity of CaliforniaSanta BarbaraCaliforniaUSA
| | - Vanessa Chou
- Department of Ecology, Evolution, and Marine BiologyUniversity of CaliforniaSanta BarbaraCaliforniaUSA
| | - Mari Irving
- Department of Ecology, Evolution, and Marine BiologyUniversity of CaliforniaSanta BarbaraCaliforniaUSA
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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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Bubica Bustos LM, Ueno AC, Biganzoli F, Card SD, Mace WJ, Martínez-Ghersa MA, Gundel PE. Can Aphid Herbivory Induce Intergenerational Effects of Endophyte-conferred Resistance in Grasses? J Chem Ecol 2022; 48:867-881. [PMID: 36372818 DOI: 10.1007/s10886-022-01390-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/20/2022] [Accepted: 10/23/2022] [Indexed: 11/15/2022]
Abstract
Plants have evolved mechanisms to survive herbivory. One such mechanism is the induction of defences upon attack that can operate intergenerationally. Cool-season grasses (sub-family Pooideae) obtain defences via symbiosis with vertically transmitted fungal endophytes (genus Epichloë) and can also show inducible responses. However, it is unknown whether these herbivore-induced responses can have intergenerational effects. We hypothesized that herbivory by aphids on maternal plants induces the intergenerational accumulation of endophyte-derived defensive alkaloids and resistance intensification in the progeny. We subjected mother plants symbiotic or not with Epichloë occultans, a species known for its production of anti-insect alkaloids known as lolines, to the aphid Rhopalosiphum padi. Then, we evaluated the progeny of these plants in terms of loline alkaloid concentration, resistance level (through herbivore performance), and shoot biomass. Herbivory on mother plants did not increase the concentration of lolines in seeds but it tended to affect loline concentration in progeny plants. There was an overall herbivore-induced intergenerational effect increasing the endophyte-conferred defence and resistance. Symbiotic plants were more resistant to aphids and had higher shoot biomass than their non-symbiotic counterparts. Since maternal herbivory did not affect the loline concentrations in seeds, the greater resistance of the progeny could have resulted from an inherited mechanism of epigenetic regulation. It would be interesting to elucidate the origin of this regulation since it could come from the host or the fungal symbiont. Thus, endophyte-driven differential fitness between symbiotic and non-symbiotic plants might be higher as generations pass on in presence of herbivores.
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Affiliation(s)
| | - Andrea C Ueno
- IFEVA, Facultad de Agronomía, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
- Centro de Ecología Integrativa, Instituto de Ciencias Biológicas, Universidad de Talca, Campus Lircay, Talca, Chile
| | - Fernando Biganzoli
- Departamento de Métodos Cuantitativos y Sistemas de Información, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Stuart D Card
- Resilient Agriculture, Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
| | - Wade J Mace
- Resilient Agriculture, Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
| | | | - Pedro E Gundel
- IFEVA, Facultad de Agronomía, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina.
- Centro de Ecología Integrativa, Instituto de Ciencias Biológicas, Universidad de Talca, Campus Lircay, Talca, Chile.
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Bastías DA, Bustos LB, Jáuregui R, Barrera A, Acuña-Rodríguez IS, Molina-Montenegro MA, Gundel PE. Epichloë Fungal Endophytes Influence Seed-Associated Bacterial Communities. Front Microbiol 2022; 12:795354. [PMID: 35058911 PMCID: PMC8764391 DOI: 10.3389/fmicb.2021.795354] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/24/2021] [Indexed: 11/30/2022] Open
Abstract
Seeds commonly harbour diverse bacterial communities that can enhance the fitness of future plants. The bacterial microbiota associated with mother plant’s foliar tissues is one of the main sources of bacteria for seeds. Therefore, any ecological factor influencing the mother plant’s microbiota may also affect the diversity of the seed’s bacterial community. Grasses form associations with beneficial vertically transmitted fungal endophytes of genus Epichloë. The interaction of plants with Epichloë endophytes and insect herbivores can influence the plant foliar microbiota. However, it is unknown whether these interactions (alone or in concert) can affect the assembly of bacterial communities in the produced seed. We subjected Lolium multiflorum plants with and without its common endophyte Epichloë occultans (E+, E-, respectively) to an herbivory treatment with Rhopalosiphum padi aphids and assessed the diversity and composition of the bacterial communities in the produced seed. The presence of Epichloë endophytes influenced the seed bacterial microbiota by increasing the diversity and affecting the composition of the communities. The relative abundances of the bacterial taxa were more similarly distributed in communities associated with E+ than E- seeds with the latter being dominated by just a few bacterial groups. Contrary to our expectations, seed bacterial communities were not affected by the aphid herbivory experienced by mother plants. We speculate that the enhanced seed/seedling performance documented for Epichloë-host associations may be explained, at least in part, by the Epichloë-mediated increment in the seed-bacterial diversity, and that this phenomenon may be applicable to other plant-endophyte associations.
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Affiliation(s)
- Daniel A Bastías
- AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand
| | - Ludmila Bubica Bustos
- IFEVA, CONICET, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Ruy Jáuregui
- AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand
| | - Andrea Barrera
- Laboratorio de Ecología Integrativa, Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile
| | - Ian S Acuña-Rodríguez
- Laboratorio de Ecología Integrativa, Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile
| | - Marco A Molina-Montenegro
- Laboratorio de Ecología Integrativa, Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile.,Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Universidad Católica del Norte, Coquimbo, Chile.,Centro de Investigación de Estudios Avanzados del Maule, Universidad Católica del Maule, Talca, Chile
| | - Pedro E Gundel
- IFEVA, CONICET, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina.,Laboratorio de Ecología Integrativa, Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile
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6
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Ueno AC, Gundel PE, Molina-Montenegro MA, Ramos P, Ghersa CM, Martínez-Ghersa MA. Getting ready for the ozone battle: Vertically transmitted fungal endophytes have transgenerational positive effects in plants. PLANT, CELL & ENVIRONMENT 2021; 44:2716-2728. [PMID: 33721328 DOI: 10.1111/pce.14047] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 03/09/2021] [Accepted: 03/10/2021] [Indexed: 06/12/2023]
Abstract
Ground-level ozone is a global air pollutant with high toxicity and represents a threat to plants and microorganisms. Although beneficial microorganisms can improve host performance, their role in connecting environmentally induced maternal plant phenotypes to progeny (transgenerational effects [TGE]) is unknown. We evaluated fungal endophyte-mediated consequences of maternal plant exposure to ozone on performance of the progeny under contrasting scenarios of the same factor (high and low) at two stages: seedling and young plant. With no variation in biomass, maternal ozone-induced oxidative damage in the progeny that was lower in endophyte-symbiotic plants. This correlated with an endophyte-mediated higher concentration of proline, a defence compound associated with stress control. Interestingly, ozone-induced TGE was not associated with reductions in plant survival. On the contrary, there was an overall positive effect on seedling survival in the presence of endophytes. The positive effect of maternal ozone increasing young plant survival was irrespective of symbiosis and only expressed under high ozone condition. Our study shows that hereditary microorganisms can modulate the capacity of plants to transgenerationally adjust progeny phenotype to atmospheric change.
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Affiliation(s)
- Andrea C Ueno
- Facultad de Agronomía, IFEVA, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
| | - Pedro E Gundel
- Facultad de Agronomía, IFEVA, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
- Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile
| | - Marco A Molina-Montenegro
- Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile
- Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Universidad Católica del Norte, Coquimbo, Chile
- Centro de Investigación y Estudios Avanzados del Maule (CIEAM), Universidad Católica del Maule, Talca, Chile
| | - Patricio Ramos
- Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile
- Núcleo Científico Multidisciplinario-DI, Universidad de Talca, Talca, Chile
| | - Claudio M Ghersa
- Facultad de Agronomía, IFEVA, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
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Alam B, Lǐ J, Gě Q, Khan MA, Gōng J, Mehmood S, Yuán Y, Gǒng W. Endophytic Fungi: From Symbiosis to Secondary Metabolite Communications or Vice Versa? FRONTIERS IN PLANT SCIENCE 2021; 12:791033. [PMID: 34975976 PMCID: PMC8718612 DOI: 10.3389/fpls.2021.791033] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 11/29/2021] [Indexed: 05/08/2023]
Abstract
Endophytic fungi (EF) are a group of fascinating host-associated fungal communities that colonize the intercellular or intracellular spaces of host tissues, providing beneficial effects to their hosts while gaining advantages. In recent decades, accumulated research on endophytic fungi has revealed their biodiversity, wide-ranging ecological distribution, and multidimensional interactions with host plants and other microbiomes in the symbiotic continuum. In this review, we highlight the role of secondary metabolites (SMs) as effectors in these multidimensional interactions, and the biosynthesis of SMs in symbiosis via complex gene expression regulation mechanisms in the symbiotic continuum and via the mimicry or alteration of phytochemical production in host plants. Alternative biological applications of SMs in modern medicine, agriculture, and industry and their major classes are also discussed. This review recapitulates an introduction to the research background, progress, and prospects of endophytic biology, and discusses problems and substantive challenges that need further study.
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Affiliation(s)
- Beena Alam
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Jùnwén Lǐ
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Qún Gě
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Mueen Alam Khan
- Department of Plant Breeding & Genetics, University College of Agriculture and Environmental Sciences, The Islamia University of Bahawalpur (IUB), Bahawalpur, Pakistan
| | - Jǔwǔ Gōng
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Shahid Mehmood
- Biotechnology Research Institute (BRI), Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yǒulù Yuán
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
- *Correspondence: Wànkuí Gǒng,
| | - Wànkuí Gǒng
- State Key Laboratory of Cotton Biology, Key Laboratory of Biological and Genetic Breeding of Cotton, The Ministry of Agriculture, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
- Yǒulù Yuán,
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8
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Ueno AC, Gundel PE, Ghersa CM, Demkura PV, Card SD, Mace WJ, Martínez-Ghersa MA. Ontogenetic and trans-generational dynamics of a vertically transmitted fungal symbiont in an annual host plant in ozone-polluted settings. PLANT, CELL & ENVIRONMENT 2020; 43:2540-2550. [PMID: 32705695 DOI: 10.1111/pce.13859] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 06/22/2020] [Accepted: 07/20/2020] [Indexed: 06/11/2023]
Abstract
Tropospheric ozone is an abiotic stress of increasing importance in the context of global climate change. This greenhouse gas is a potent phytotoxic molecule with demonstrated negative effects on crop yield and natural ecosystems. Recently, oxidative stress has been proposed as a mechanism that could regulate the interaction between cool-season grasses and Epichloë endophytes. We hypothesized that exposure of Lolium multiflorum plants, hosting endophytes to an ozone-polluted environment at different ontogenetic phases, would impact the trans-generational dynamics of the vertically transmitted fungal symbiont. Here, we found that the ozone-induced stress on the mother plants did not affect the endophyte vertical transmission but it impaired the persistence of the fungus in the seed exposed to artificial ageing. Endophyte longevity in seed was reduced by exposure of the mother plant to ozone. Although ozone exposure did not influence either the endophyte mycelial concentration or their compound defences (loline alkaloids), a positive correlation was observed between host fitness and the concentration of endophyte-derived defence compounds. This suggests that fungal defences in grass seeds were not all produced in situ but remobilized from the vegetative tissues. Our study reveals ozone trans-generational effects on the persistence of a beneficial symbiont in a host grass.
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Affiliation(s)
- Andrea C Ueno
- IFEVA, Facultad de Agronomía, Departamento de Recursos Naturales y Ambiente, CONICET, Universidad de Buenos Aires, Av. San Martín 4453, Buenos Aires, C1417DSE, Argentina
| | - Pedro E Gundel
- IFEVA, Facultad de Agronomía, Departamento de Recursos Naturales y Ambiente, CONICET, Universidad de Buenos Aires, Av. San Martín 4453, Buenos Aires, C1417DSE, Argentina
| | - Claudio M Ghersa
- IFEVA, Facultad de Agronomía, Departamento de Recursos Naturales y Ambiente, CONICET, Universidad de Buenos Aires, Av. San Martín 4453, Buenos Aires, C1417DSE, Argentina
| | - Patricia V Demkura
- IFEVA, Facultad de Agronomía, Departamento de Recursos Naturales y Ambiente, CONICET, Universidad de Buenos Aires, Av. San Martín 4453, Buenos Aires, C1417DSE, Argentina
| | - Stuart D Card
- Forage Science, AgResearch Limited, Grasslands Research Centre, Palmerston North, Private Bag 11008, New Zealand
| | - Wade J Mace
- Forage Science, AgResearch Limited, Grasslands Research Centre, Palmerston North, Private Bag 11008, New Zealand
| | - María Alejandra Martínez-Ghersa
- IFEVA, Facultad de Agronomía, Departamento de Recursos Naturales y Ambiente, CONICET, Universidad de Buenos Aires, Av. San Martín 4453, Buenos Aires, C1417DSE, Argentina
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Maternal Exposure to Ozone Modulates the Endophyte-Conferred Resistance to Aphids in Lolium multiflorum Plants. INSECTS 2020; 11:insects11090548. [PMID: 32824905 PMCID: PMC7564161 DOI: 10.3390/insects11090548] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/06/2020] [Accepted: 08/11/2020] [Indexed: 01/29/2023]
Abstract
Plants are challenged by biotic and abiotic stress factors and the incidence of one can increase or decrease resistance to another. These relations can also occur transgenerationally. For instance, progeny plants whose mothers experienced herbivory can be more resistant to herbivores. Certain fungal endophytes that are vertically transmitted endow plants with alkaloids and resistance to herbivores. However, endophyte-symbiotic plants exposed to the oxidative agent ozone became susceptible to aphids. Here, we explored whether this effect persists transgenerationally. We exposed Lolium multiflorum plants with and without fungal endophyte Epichloë occultans to ozone (120 or 0 ppb), and then, challenged the progeny with aphids (Rhopalosiphum padi). The endophyte was the main factor determining the resistance to aphids, but its importance diminished in plants with ozone history. This negative ozone effect on the endophyte-mediated resistance was apparent on aphid individual weights. Phenolic compounds in seeds were increased by the symbiosis and diminished by the ozone. The endophyte effect on phenolics vanished in progeny plants while the negative ozone effect persisted. Independently of ozone, the symbiosis increased the plant biomass (≈24%). Although ozone can diminish the importance of endophyte symbiosis for plant resistance to herbivores, it would be compensated by host growth stimulation.
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10
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Gundel PE, Sun P, Charlton ND, Young CA, Miller TEX, Rudgers JA. Simulated folivory increases vertical transmission of fungal endophytes that deter herbivores and alter tolerance to herbivory in Poa autumnalis. ANNALS OF BOTANY 2020; 125:981-991. [PMID: 32010946 PMCID: PMC7218812 DOI: 10.1093/aob/mcaa021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 01/31/2020] [Indexed: 05/02/2023]
Abstract
BACKGROUND AND AIMS The processes that maintain variation in the prevalence of symbioses within host populations are not well understood. While the fitness benefits of symbiosis have clearly been shown to drive changes in symbiont prevalence, the rate of transmission has been less well studied. Many grasses host symbiotic fungi (Epichloë spp.), which can be transmitted vertically to seeds or horizontally via spores. These symbionts may protect plants against herbivores by producing alkaloids or by increasing tolerance to damage. Therefore, herbivory may be a key ecological factor that alters symbiont prevalence within host populations by affecting either symbiont benefits to host fitness or the symbiont transmission rate. Here, we addressed the following questions: Does symbiont presence modulate plant tolerance to herbivory? Does folivory increase symbiont vertical transmission to seeds or hyphal density in seedlings? Do plants with symbiont horizontal transmission have lower rates of vertical transmission than plants lacking horizontal transmission? METHODS We studied the grass Poa autumnalis and its symbiotic fungi in the genus Epichloë. We measured plant fitness (survival, growth, reproduction) and symbiont transmission to seeds following simulated folivory in a 3-year common garden experiment and surveyed natural populations that varied in mode of symbiont transmission. KEY RESULTS Poa autumnalis hosted two Epichloë taxa, an undescribed vertically transmitted Epichloë sp. PauTG-1 and E. typhina subsp. poae with both vertical and horizontal transmission. Simulated folivory reduced plant survival, but endophyte presence increased tolerance to damage and boosted fitness. Folivory increased vertical transmission and hyphal density within seedlings, suggesting induced protection for progeny of damaged plants. Across natural populations, the prevalence of vertical transmission did not correlate with symbiont prevalence or differ with mode of transmission. CONCLUSIONS Herbivory not only mediated the reproductive fitness benefits of symbiosis, but also promoted symbiosis prevalence by increasing vertical transmission of the fungus to the next generation. Our results reveal a new mechanism by which herbivores could influence the prevalence of microbial symbionts in host populations.
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Affiliation(s)
- Pedro E Gundel
- IFEVA-CONICET, Department of Ecology, College of Agronomy, University of Buenos Aires, Buenos Aires, Argentina
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
- For correspondence. E-mail
| | - Prudence Sun
- Department of Biosciences, Rice University, Houston, TX, USA
| | | | | | - Tom E X Miller
- Department of Biosciences, Rice University, Houston, TX, USA
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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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12
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Song QY, Li F, Nan ZB, Coulter JA, Wei WJ. Do Epichloë Endophytes and Their Grass Symbiosis Only Produce Toxic Alkaloids to Insects and Livestock? JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:1169-1185. [PMID: 31922733 DOI: 10.1021/acs.jafc.9b06614] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Epichloë endophytes in forage grasses have attracted widespread attention and interest of chemistry researchers as a result of the various unique chemical structures and interesting biological activities of their secondary metabolites. This review describes the diversity of unique chemical structures of taxa from Epichloë endophytes and grass infected with Epichloë endophytes and demonstrates their reported biological activities. Until now, nearly 160 secondary metabolites (alkaloids, peptides, indole derivatives, pyrimidines, sesquiterpenoids, flavonoids, phenol and phenolic acid derivatives, aliphatic metabolites, sterols, amines and amides, and others) have been reported from Epichloë endophytes and grass infected with Epichloë endophytes. Among these, non-alkaloids account for half of the population of total metabolites, indicating that they also play an important role in Epichloë endophytes and grass infected with Epichloë endophytes. Also, a diverse array of secondary metabolites isolated from Epichloë endophytes and symbionts is a rich source for developing new pesticides and drugs. Bioassays disclose that, in addition to toxic alkaloids, the other metabolites isolated from Epichloë endophytes and symbionts have notable biological activities, such as antifungal, anti-insect, and phytotoxic activities. Accordingly, the biological functions of non-alkaloids should not be neglected in the future investigation of Epichloë endophytes and symbionts.
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Affiliation(s)
- Qiu-Yan Song
- State Key Laboratory of Grassland Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture, College of Pastoral Agriculture Science and Technology , Lanzhou University , Lanzhou , Gansu 730020 , People's Republic of China
| | - Fan Li
- State Key Laboratory of Grassland Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture, College of Pastoral Agriculture Science and Technology , Lanzhou University , Lanzhou , Gansu 730020 , People's Republic of China
| | - Zhi-Biao Nan
- State Key Laboratory of Grassland Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture, College of Pastoral Agriculture Science and Technology , Lanzhou University , Lanzhou , Gansu 730020 , People's Republic of China
| | - Jeffrey A Coulter
- Department of Agronomy and Plant Genetics , University of Minnesota , St. Paul , Minnesota 55108 , United States
| | - Wen-Jun Wei
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou , Gansu 730000 , People's Republic of China
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13
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Bastías DA, Martínez-Ghersa MA, Newman JA, Card SD, Mace WJ, Gundel PE. Sipha maydis sensitivity to defences of Lolium multiflorum and its endophytic fungus Epichloë occultans. PeerJ 2019; 7:e8257. [PMID: 31976166 PMCID: PMC6966988 DOI: 10.7717/peerj.8257] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 11/20/2019] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Plants possess a sophisticated immune system to defend from herbivores. These defence responses are regulated by plant hormones including salicylic acid (SA) and jasmonic acid (JA). Sometimes, plant defences can be complemented by the presence of symbiotic microorganisms. A remarkable example of this are grasses establishing symbiotic associations with Epichloë fungal endophytes. We studied the level of resistance provided by the grass' defence hormones, and that provided by Epichloë fungal endophytes, against an introduced herbivore aphid. These fungi protect their hosts against herbivores by producing bioactive alkaloids. We hypothesized that either the presence of fungal endophytes or the induction of the plant salicylic acid (SA) defence pathway would enhance the level of resistance of the grass to the aphid. METHODS Lolium multiflorum plants, with and without the fungal endophyte Epichloë occultans, were subjected to an exogenous application of SA followed by a challenge with the aphid, Sipha maydis. RESULTS Our results indicate that neither the presence of E. occultans nor the induction of the plant's SA pathway regulate S. maydis populations. However, endophyte-symbiotic plants may have been more tolerant to the aphid feeding because these plants produced more aboveground biomass. We suggest that this insect insensitivity could be explained by a combination between the ineffectiveness of the specific alkaloids produced by E. occultans in controlling S. maydis aphids and the capacity of this herbivore to deal with hormone-dependent defences of L. multiflorum.
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Affiliation(s)
- Daniel A. Bastías
- IFEVA, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Buenos Aires, Argentina
- Forage Science, AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand
| | | | - Jonathan A. Newman
- Department of Biology, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - Stuart D. Card
- Forage Science, AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand
| | - Wade J. Mace
- Forage Science, AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand
| | - Pedro E. Gundel
- IFEVA, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Buenos Aires, Argentina
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Ray T, Pandey SS, Pandey A, Srivastava M, Shanker K, Kalra A. Endophytic Consortium With Diverse Gene-Regulating Capabilities of Benzylisoquinoline Alkaloids Biosynthetic Pathway Can Enhance Endogenous Morphine Biosynthesis in Papaver somniferum. Front Microbiol 2019; 10:925. [PMID: 31114562 PMCID: PMC6503101 DOI: 10.3389/fmicb.2019.00925] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/11/2019] [Indexed: 11/21/2022] Open
Abstract
Secondary metabolite biosynthesis in medicinal plants is multi-step cascade known to be modulated by associated endophytes. While a single endophyte is not able to upregulate all biosynthetic steps, limiting maximum yield achievement. Therefore to compliment the deficient characteristics in an endophyte we tried consortium of endophytes to achieve maximum yield. Here, efforts were made to maximize the in planta morphine yield, using consortium of two endophytes; SM1B (Acinetobacter sp.) upregulating most of the genes of morphine biosynthesis except T6ODM and CODM, and SM3B (Marmoricola sp.) upregulating T6ODM and CODM in alkaloid-less Papaver somniferum cv. Sujata. Consortium-inoculation significantly increased morphine and thebaine content, and also increased the photosynthetic efficiency of poppy plants resulted in increased biomass, capsule weight, and seed yields compared to single-inoculation. The increment in morphine content was due to the modulation of metabolic-flow of key intermediates including reticuline and thebaine, via upregulating pertinent biosynthetic genes and enhanced expression of COR, key gene for morphine biosynthesis. This is the first report demonstrating the endophytic-consortium complimenting the functional deficiency of one endophyte by another for upregulating multiple genes of a metabolic pathway similar to transgenics (overexpressing multiple genes) for obtaining enhanced yield of pharmaceutically important metabolites.
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Affiliation(s)
- Tania Ray
- Microbial Technology Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Shiv S Pandey
- Microbial Technology Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Alok Pandey
- Biotechnology Division, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Madhumita Srivastava
- Analytical Chemistry Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Karuna Shanker
- Analytical Chemistry Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Alok Kalra
- Microbial Technology Department, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
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