A1 Refereed original research article in a scientific journal
Can Epichloe endophytes enhance direct and indirect plant defence?
Authors: Fuchs B, Krauss J
Publisher: ELSEVIER SCI LTD
Publication year: 2019
Journal: Fungal Ecology
Journal name in source: FUNGAL ECOLOGY
Journal acronym: FUNGAL ECOL
Volume: 38
First page : 98
Last page: 103
Number of pages: 6
ISSN: 1754-5048
eISSN: 1878-0083
DOI: https://doi.org/10.1016/j.funeco.2018.07.002(external)
Abstract
Induced or constitutive production of secondary metabolites is a successful plant defence strategy against herbivores which can be mediated by plant associated micro-organisms. Several grass species can be associated with an endophytic fungus of the genus Epichloe which produces herbivore toxic or deterring alkaloids. Besides these direct defences, herbivorous insects are controlled via indirect plant defence mechanisms by attracting predators. Recent studies indicate that Epichloe endophytes can improve the grass emitted volatile organic compounds towards herbivore deterrence. Due to their defensive mutualistic function, we hypothesize that Epichloe altered plant volatiles can attract aphid predators and contribute to an increased indirect plant defence. With a common garden study, we show that hoverfly (Syrphidae) larvae and pupae were more abundant on endophyte-infected plants compared to uninfected plants. Our results indicate that the Epichloe endophyte provides, besides direct defence (alkaloid), indirect plant defence by improving the plant odor attracting more olfactory foraging aphid predators. Future research is needed in order to understand: (I) whether endophyte-mediated changes in plant volatiles are induced herbivore specific, (II) whether there is a trade-off between endophytemediated direct and indirect plant defence, (Ill) whether the endophyte produces volatiles or induces a change in plant -derived volatiles, (IV) the role of plant signals in endophyte-mediated plant defence. (C) 2018 Elsevier Ltd and British Mycological Society. All rights reserved.
Induced or constitutive production of secondary metabolites is a successful plant defence strategy against herbivores which can be mediated by plant associated micro-organisms. Several grass species can be associated with an endophytic fungus of the genus Epichloe which produces herbivore toxic or deterring alkaloids. Besides these direct defences, herbivorous insects are controlled via indirect plant defence mechanisms by attracting predators. Recent studies indicate that Epichloe endophytes can improve the grass emitted volatile organic compounds towards herbivore deterrence. Due to their defensive mutualistic function, we hypothesize that Epichloe altered plant volatiles can attract aphid predators and contribute to an increased indirect plant defence. With a common garden study, we show that hoverfly (Syrphidae) larvae and pupae were more abundant on endophyte-infected plants compared to uninfected plants. Our results indicate that the Epichloe endophyte provides, besides direct defence (alkaloid), indirect plant defence by improving the plant odor attracting more olfactory foraging aphid predators. Future research is needed in order to understand: (I) whether endophyte-mediated changes in plant volatiles are induced herbivore specific, (II) whether there is a trade-off between endophytemediated direct and indirect plant defence, (Ill) whether the endophyte produces volatiles or induces a change in plant -derived volatiles, (IV) the role of plant signals in endophyte-mediated plant defence. (C) 2018 Elsevier Ltd and British Mycological Society. All rights reserved.