Conversion of verbenols to verbenone by yeasts isolated fromDendroctonus ponderosae (Coleoptera: Scolytidae)

Abstract

A variety of symbionts associated with bark beetles are capable of producing compounds that are used as pheromones by their hosts. We report that two yeasts associated withDendroctonus ponderosae Hopkins,Hansenula capsulata Wickerham, andPichiapinus (Hoist) Phaff, are capable of convertingcis- andtrans-verbenol efficiently into verbenone.trans-Verbenol, which is produced by femaleD. ponderosae, acts as an aggregation pheromone for this scolytid, while verbenone, which other studies have indicated that microbe-reducedD. ponderosae are incapable of producing, acts as an antiaggregation pheromone.D. ponderosae appears to rely primarily on microbial symbionts for terminating aggregation and mass attack on individual host trees.

Dynamics of pheromone production and communication in the mountain pine beetle, Dendroctonus ponderosae Hopkins, and the pine engraver, Ips pini (Say) (Coleoptera: Scolytidae)

“…tubes was possibly due to the oxidation of a-pinene in the guts of dying beetles either spontaneously or by intestinal microbes Hunt and Borden 1990). Under normal conditions, emerged beettes may avoid k i n g attractive by metabolising tram-verbenol into verbenene, p-mentha-1,5,8-triene or cyrnene (Gnes et al 1990b).…”

“…1969;Rudinsky et al 1974a). Hunt and Borden 1990). Therefore, a tree at an advanced stage of attack would exude verbenone at levels that would signal a limited fresh resource.…”

Semiochemicals in the Natural History of Southern Pine Beetle Dendroctonus frontalis Zimmermann and Their Role in Pest Management

“…Verbenone (and verbenol) can be generated through autoxidation of host-released α-pinene coming into contact with atmospheric oxygen (Hunt et al, 1989;Moore et al, 1956). Microbes including bark beetle symbionts and incidental associates are also capable of oxidizing α-pinene to verbenol and/or verbenol to verbenone Brand et al, 1975;Hunt and Borden, 1990;Xu et al, 2015). A fungus carried in the mycangium of female D. frontalis (Ceratocystiopsis ranaculosus J.R. Bridges and T.J. Perry) was shown to convert verbenol to verbenone (Brand et al, 1976).…”

Fungal Frequency and Mite Load Trends Interact with a Declining Mountain Pine Beetle Population

“…Yeasts are the most prevalent ascomycetes on many bark beetles [7][8][9], including the MPB [10][11][12]. Yeasts perform essential functions that impact MPB success in the newly attacked tree such as metabolizing alpha-pinene into verbenone, a semiochemical acting as an anti-aggregation pheromone during MPB mass-attacks and signaling attack saturation [13]. Yeasts are reviewed elsewhere [14,15], and here we focus on filamentous blue-staining species.…”