Z-3-Hexenylacetate emissions induced by the endophyte Epichloë occultans at different levels of defoliation during the host plant's life cycle

• Published in: Fungal ecology Vol. 49; p. 101015
• Main Authors: Fiorenza, Juan Esteban, Fernández, Patricia Carina, Omacini, Marina
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-02-2021
• Subjects: Associational protection; Grass fungal endophytes; Induced defences; Life cycle; Lolium multiflorum; Protective mutualism; Symbiosis; Volatile emission; Symbiosis; Life cycle; Protective mutualism; Associational protection; Lolium multiflorum; Volatile emission; Grass fungal endophytes; Induced defences
• ISSN: 1754-5048
• DOI: 10.1016/j.funeco.2020.101015

Vertically transmitted fungal endophytes are common defensive symbionts of cool-season grasses. Protection against herbivores has been generally associated with alkaloids produced in the grass-endophyte symbiosis. However, many other changes occur in host metabolism like the release of VOCs. We aimed at characterizing the profile of volatile organic compounds (VOCs) induced by simultaneous fungal endophyte symbiosis and defoliation during the entire life cycle of the annual host grass and the asexual symbiont. We designed an outdoor factorial experiment with plots dominated by intact and damaged Lolium multiflorum plants with high and low infection levels with Epichloë occultans. After exploring the entire VOC profile, the green leaf volatile (Z)-3-hexenyl acetate (Z3-HAC) was found as the main compound emitted by the plants under field conditions. While in low-infected patches there were no differences in volatile emission during the plant life cycle, highly infected patches emitted more Z3-HAC in seedling and vegetative phases than in the reproductive phase. The role of Z3-HAC provided by symbiotic to neighbouring non-symbiotic plants in the associational protection against herbivores and fungal pathogens is discussed.