Special Interest Group Meeting

Overview: Offensive and defensive roles of hyphal (mycelial) structures in interactions between fungi and other organisms

Akira Suzuki, Faculty of Education/Graduate School of Horticulture, Chiba University, Japan

Fungi form different kinds of hyphal (mycelial) structures, such as haustria, penetration pegs, appressoria, constricting rings, screlotia, toxocysts, mycelial cords, cystdia, pelotons, and cremia, etc., for colonization (including contact, capturing, penetration and nutrient absorption, etc.), survival against extreme environments and/or feeding by animals, and spore discharge, etc. Most hyphal (mycelial) structures have offensive and/or defensive roles in interactions not only between fungi and other organisms but also between a certain fungus and other fungi. For example, the principal role of haustria, appressoria, and constricting rings would be characterized as offensive while sclerotia would be characterized as defensive. Toxocysts have both offensive and defensive roles. Mycelial cords and cystdia have multiple ecological functions including offensive and defensive roles. Many structures formed by mycorrhizal symbiosis, such as pelotons, mantles, vescules, and arbuscules would be specialized for nutrient transport but sometimes probably affect as offensive structures. Fruiting bodies occasionally act as defensive structures by producing toxic compound(s) to avoid eating by invertebrate(s) when they are injured by their eating. For further understanding of the ecological roles of hyphal/mycelial structures in the interactions between fungi and other organisms (including a certain fungus and other fungi), we should examine their indirect roles as well as their direct roles, e.g. production of volatile and diffusible compounds which have been examined in many mycelial strands and mycorrhizae.