Dissection of the epoxyjanthitrem pathway in Epichloë sp. LpTG-3 strain AR37 by CRISPR gene editing

Miller, Taryn A.; Hudson, Debbie; Johnson, Richard D.; Singh, Jaspreet; Mace, Wade J.; Forester, Natasha T.; Maclean, Paul; Voisey, Christine R.; Johnson, Linda J.

doi:10.3389/ffunb.2022.944234

Cited by 12 publications

(5 citation statements)

References 56 publications

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“…However, the unequivocal confirmation of the mechanism might come from experiments that manipulate the alkaloid levels. The use of plants associated with gene‐edited endophytes with decreased and no production of alkaloids would be an elegant system to evaluate the endophyte‐mediated mechanism of the trade‐off decoupling and also to quantify the costs associated with this mechanism (Hudson et al, 2021; Miller et al, 2022). Further experiments could also investigate the changes in the phytohormonal networks and plant resource levels associated with the ability of endophytes to alleviate the trade‐off.…”

Section: Conclusion and Future Perspectivesmentioning

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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Section: Conclusion and Future Perspectivesmentioning

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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“…This may be because endophytes that are exclusively vertically transmitted do not present growth stages outside plants, thus the effects of environmental factors on the fungus cannot be easily separated from the effects on plants. However, the evaluation of endophyte transcriptomes and gene-edited endophytes are interesting approaches to improve the understanding of the direct effects the global change factors on the fungus [131,132]. We described the mechanisms by which endophytes may counteract the detrimental effects of the global change factors.…”

Section: Concluding Remarks and Future Perspectivesmentioning

confidence: 99%

Global Change Factors Influence Plant-Epichloë Associations

Bastías

Ueno

Gundel

2023

JoF

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There is an increasing interest in determining the influence of global change on plant–microorganism interactions. We review the results of experiments that evaluated the effects of the global change factors carbon dioxide, ozone, temperature, drought, flooding, and salinity on plant symbioses with beneficial Epichloë endophytes. The factors affected the performance of both plants and endophytes as well as the frequency of plants symbiotic with the fungus. Elevated carbon dioxide levels and low temperatures differentially influenced the growth of plants and endophytes, which could compromise the symbioses. Furthermore, we summarise the plant stage in which the effects of the factors were quantified (vegetative, reproductive, or progeny). The factors ozone and drought were studied at all plant stages, but flooding and carbon dioxide were studied in just a few of them. While only studied in response to ozone and drought, evidence showed that the effects of these factors on symbiotic plants persisted trans-generationally. We also identified the putative mechanisms that would explain the effects of the factors on plant–endophyte associations. These mechanisms included the increased contents of reactive oxygen species and defence-related phytohormones, reduced photosynthesis, and altered levels of plant primary metabolites. Finally, we describe the counteracting mechanisms by which endophytes would mitigate the detrimental effects of the factors on plants. In presence of the factors, endophytes increased the contents of antioxidants, reduced the levels of defence-related phytohormones, and enhanced the plant uptake of nutrients and photosynthesis levels. Knowledge gaps regarding the effects of global change on plant–endophyte associations were identified and discussed.

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“…For the alkaloid analysis, 50 mg (± 5 mg) of freeze-dried plant material was weighed into 2 mL screw cap vials and further ground with a bead ruptor (FastPrep FP120, Savant Instruments Inc., Farmingdale, NY, USA) along with 3 × 3 mm stainless steel beads to increase the efficiency of alkaloid extraction. Alkaloids such as peramine, lolitrem B, ergovaline, and epoxyjanthitrems were analysed using the methods described in Miller et al (2022). The limit of detection of each of the analytes was 0.1 µg g -1 .…”

Section: Chemical Analysismentioning

confidence: 99%

Root aphid (Aploneura lentisci) population size on perennial ryegrass is determined by drought and endophyte strain

et al. 2023

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Climate change is anticipated to lead to an increase in the occurrence and intensity of drought and fluctuations in insect cycles that will challenge modern pasture systems. Feeding by root aphids such as Aploneura lentisci Pass. can be a significant challenge to pastures. These below-ground living aphids are commonly found in New Zealand and Australia, feeding year-round on the roots of graminaceous plants such as perennial ryegrass (Lolium perenne L.). Some strains of the fungal endophyte Epichloë festucae var. lolii in perennial ryegrass can provide protection against root aphids and greater resilience under drought, contributing to higher persistency and growth than endophyte-free plants. However, the interaction between insect pressure and drought is not understood. This study examined the effect of drought on root aphid populations and plant performance in perennial ryegrass plants relative to endophyte status (±) and endophyte strain (AR37, NZCT) in a glasshouse experiment. Plants were cloned across the drought and well-watered treatments, and half of the plants were inoculated with root aphids, whilst half of the plants were treated with insecticide. Endophyte infection with strain NZCT and AR37 reduced root aphid numbers. Aphid populations were significantly higher in drought-stressed than in well-watered plants in both endophyte-infected and endophyte-free treatments. Under drought conditions, root aphid populations were increased 4-fold in NZCT and 8-fold in AR37 and endophyte-free plants in comparison with their well-watered counterparts. Root aphids reduced shoot dry weight by 16% in drought-exposed and 26% in well-watered plants in comparison with their insecticide-treated counterparts whilst reducing root biomass by 49%. Our results suggest that root aphids are likely able to exploit the higher availability of amino acids in the plant sap of drought-exposed plants. This study provides evidence that climate change-mediated impacts of root aphids could reduce production in perennial ryegrass-dominant pastures. However, field trials would be necessary to determine whether this effect is seen in situ, where numerous additional factors will be operating at the same time.

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Dissection of the epoxyjanthitrem pathway in Epichloë sp. LpTG-3 strain AR37 by CRISPR gene editing

Cited by 12 publications

References 56 publications

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

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

Global Change Factors Influence Plant-Epichloë Associations

Root aphid (Aploneura lentisci) population size on perennial ryegrass is determined by drought and endophyte strain

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