Evolution of ‘pollinator’- attracting signals in fungi

Abstract

Fungi produce a plethora of secondary metabolites yet their biological significance is often little understood. Some compounds show wellknown antibiotic properties, others may serve as volatile signals for the attraction of insects that act as vectors of spores or gametes. Our investigations in an outcrossing, self-incompatible fungus show that a fungus-produced volatile compound with fungitoxic activities is also responsible for the attraction of specific insects that transfer gametes. We argue that insect attraction using this compound is likely to have evolved from its primary function of defenceas has been suggested for floral scent in the angiosperms. We, thus, propose that similar yet convergent evolutionary pathways have lead to interspecific communication signals in both fungi and plants.

Ant Interactions with Soil Organisms and Associated Semiochemicals

“…The parasitic fungi is specifically attracted to chemicals (unknown structures) released by its host fungal garden, as evidenced by preferential growth of the Escovopsis parasite toward their fungal host rather than to non-host fungi (Gerardo et al 2006). Fungi are known to produce volatiles that attract insects (Pierce et al 1991;Schiestl et al 2006) and/or have antimicrobial activity, e.g., penicillin. In addition, the Escovopsis strain isolated from host A will move quicker toward host A cultivar than toward other host cultivars, perpetuating Escovopsis strain and host fungal garden fidelity and the mutualism between the two fungi (Gerardo et al 2006).…”

A simple floral fragrance and unusual osmophore structure in Cyclopogon elatus (Orchidaceae)

“…Thus, the fact that the fragrance of C. elatus flowers is simple and dominated by one compound is unusual. The literature supports at least two models of odour specificity in pollinator attraction: (i) species-specific ratios of commonplace compounds such as in euglossine bee-pollinated orchids (Dressler 1982;Eltz et al 1999), Ophrys (Borg-Karlson 1990; Schiestl et al 1999) and Ficus (Gibernau et al 1997), or (ii) simple presence of unique or unusual odours such as in the sexually deceptive Chiloglottis (Schiestl et al 2003), Epichlöe endophyte fungi (Schiestl et al 2006) and carrion mimicry in Helicodiceros (Stensmyr et al 2002). Depending on the information content of specific volatile compounds, pollinator specificity could be enhanced by increased (e.g.…”

Secondary chemicals protect mould from fungivory

“…mycotoxins; Nesbitt et al 1962) ways. Despite the wealth of knowledge on the manifold influences of SMs on humans, the function of these compounds in interaction with fungi's natural environment is still an unresolved problem (Sherratt et al 2005;Deacon 2006;Schiestl et al 2006). Since fungi constitute an important food source for many invertebrates, one recurring hypothesis suggests fungal SMs evolved, in part, as antifeedants (Demain & Fang 2000;Scheu & Simmerling 2004) and provide a type of chemical protection analogous to SM protection of plants against herbivory (Schoonhoven et al 2006).…”