The dynamic mechanisms underpinning symbiotic Epichloë–grass interactions: implications for sustainable and resilient agriculture

Johnson, Linda J.; Bastías, Daniel A.; Caradus, J. R.; Chettri, Pranav; Forester, Natasha T.; Mace, Wade J.; Miller, Taryn A.; Moon, Christina D.; Voisey, Christine R.; Zhang, Wei; Card, Stuart D.

doi:10.1016/b978-0-12-822122-8.00008-x

Cited by 8 publications

(5 citation statements)

References 272 publications

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“…Changes in climate, management, and further pest incursions will continue to challenge the persistence of cool-season grasses making the reliance on the mutualism with Epichloë even more important. The ongoing search for novel endophytes with beneficial chemistry continues, but can now be supplemented with the use of new techniques such as gene editing to design endophyte strains for specific biotic and abiotic challenges [172,173]. The ultimate outcome will be the delivery of natural biocontrol options to protect grasses from pest and disease challenges, without the use of synthetic chemistry, and improve yield in drought conditions.…”

Section: Conclusion and Prospectsmentioning

confidence: 99%

Asexual Epichloë Fungi—Obligate Mutualists

Caradus¹,

Card

Hewitt

et al. 2021

Encyclopedia

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Asexual Epichloë are obligate fungal mutualists that form symbiosis with many temperate grass species, providing several advantages to the host. These advantages include protection against vertebrate and invertebrate herbivores (i.e., grazing livestock and invertebrate pests, respectively), improved resistance to phytopathogens, increased adaptation to drought stress, nutrient deficiency, and heavy metal-containing soils. Selected Epichloë strains are utilised in agriculture mainly for their pest resistance traits, which are moderated via the production of Epichloë-derived secondary metabolites. For pastoral agriculture, the use of these endophyte infected grasses requires the balancing of protection against insect pests with reduced impacts on animal health and welfare.

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Section: Conclusion and Prospectsmentioning

confidence: 99%

Asexual Epichloë Fungi—Obligate Mutualists

Caradus¹,

Card

Hewitt

et al. 2021

Encyclopedia

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“…Moon & Schardl) [7,10,11]. Compared to sexual endophytes, asexual Epichloë endophytes generally form mutualistic relationships with their hosts, asymptomatically colonize plant foliar tissues, and are maternally inherited through mycelia established in mature seeds [12,13]. Epichloë spp.…”

Section: Introductionmentioning

confidence: 99%

Endophytes Alleviate Drought-Derived Oxidative Damage in Achnatherum inebrians Plants Through Increasing Antioxidants and Regulating Host Stress Responses

Nie,

Zhao,

Zhang

et al. 2024

Microb Ecol

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Endophytes generally increase antioxidant contents of plants subjected to environmental stresses. However, the mechanisms by which endophytes alter the accumulation of antioxidants in plant tissues are not entirely clear. We hypothesized that, in stress situations, endophytes would simultaneously reduce oxidative damage and increase antioxidant contents of plants and that the accumulation of antioxidants would be a consequence of the endophyte ability to regulate the expression of plant antioxidant genes. We investigated the effects of the fungal endophyte Epichloë gansuensis (C.J. Li & Nan) on oxidative damage, antioxidant contents, and expression of representative genes associated with antioxidant pathways in Achnatherum inebrians (Hance) Keng plants subjected to low (15%) and high (60%) soil moisture conditions. Gene expression levels were measured using RNA-seq. As expected, the endophyte reduced the oxidative damage by 17.55% and increased the antioxidant contents by 53.14% (on average) in plants subjected to low soil moisture. In line with the accumulation of antioxidants in plant tissues, the endophyte increased the expression of most plant genes associated with the biosynthesis of antioxidants (e.g., MIOX, crtB, gpx) while it reduced the expression of plant genes related to the metabolization of antioxidants (e.g., GST, PRODH, ALDH). Our findings suggest that endophyte ability of increasing antioxidant contents in plants may reduce the oxidative damage caused by stresses and that the fungal regulation of plant antioxidants would partly explain the accumulation of these compounds in plant tissues.

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“…Plant‐beneficial microbes that can provide plants with mechanisms of growth promotion and/or protection against attackers may relieve the plant growth‐defence trade‐off (Bennett et al, 2006; Pangesti et al, 2013). Examples of this are asexual endophytic fungi of the genus Epichloë that form mutualistic associations with grasses of the subfamily Pooideae (Johnson et al, 2021; Schardl et al, 2004). These endophytes can simultaneously increase plant defences and enhance the growth of their plant hosts (Bastías et al, 2021; Bastías, Gundel, et al, 2022; Gundel et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…Due to the nature of vertical transmission, the fitness of Epichloë endophytes is strongly aligned with the fitness of their plant hosts since plant reproduction offers the opportunity for these symbionts to multiply and disperse (Bastías & Gundel, 2023; Gundel et al, 2011). The most documented benefit of Epichloë to their plant hosts is the fungal provision of antiherbivore alkaloids (Bastias et al, 2017; Johnson et al, 2021). The Epichloë ‐derived alkaloids are systemically distributed within the aboveground tissues of their plant hosts, with four chemical classes characterised to date: the ergot alkaloids (e.g., ergovaline), indole‐diterpenes (e.g., epoxyjanthitrems), pyrrolizidines (e.g., lolines) and pyrrolopyrazines (peramine) (Caradus & Johnson, 2020; Schardl et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

The growth promotion in endophyte symbiotic plants does not penalise the resistance to herbivores and bacterial microbiota

Zhang,

Gundel,

Jáuregui

et al. 2024

Plant Cell & Environment

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A trade‐off between growth and defence against biotic stresses is common in plants. Fungal endophytes of the genus Epichloë may relieve this trade‐off in their host grasses since they can simultaneously induce plant growth and produce antiherbivore alkaloids that circumvent the need for host defence. The Epichloë ability to decouple the growth‐defence trade‐off was evaluated by subjecting ryegrass with and without Epichloë endophytes to an exogenous treatment with gibberellin (GA) followed by a challenge with Rhopalosiphum padi aphids. In agreement with the endophyte‐mediated trade‐off decoupling hypothesis, the GA‐derived promotion of plant growth increased the susceptibility to aphids in endophyte‐free plants but did not affect the insect resistance in endophyte‐symbiotic plants. In line with the unaltered insect resistance, the GA treatment did not reduce the concentration of Epichloë‐derived alkaloids. The Epichloë mycelial biomass was transiently increased by the GA treatment but at the expense of hyphal integrity. The response of the phyllosphere bacterial microbiota to both GA treatment and Epichloë was also evaluated. Only Epichloë, and not the GA treatment, altered the composition of the phyllosphere microbiota and the abundance of certain bacterial taxa. Our findings clearly demonstrate that Epichloë does indeed relieve the plant growth‐defence trade‐off.

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The dynamic mechanisms underpinning symbiotic Epichloë–grass interactions: implications for sustainable and resilient agriculture

Cited by 8 publications

References 272 publications

Asexual Epichloë Fungi—Obligate Mutualists

Asexual Epichloë Fungi—Obligate Mutualists

Endophytes Alleviate Drought-Derived Oxidative Damage in Achnatherum inebrians Plants Through Increasing Antioxidants and Regulating Host Stress Responses

The growth promotion in endophyte symbiotic plants does not penalise the resistance to herbivores and bacterial microbiota

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