Ectomycorrhizal Influence on the Dynamics of Sesquiterpene Release by .

is an ectomycorrhizal basidiomycete with high host specificity. The slow-growing fungus is able to produce twenty sesquiterpenes, including α-barbatene, sativene, isocaryophyllene, α-cuprenene, β-cedrene, ß-copaene, 4-epi-α-acoradiene, and chamigrene in axenic culture. For the three major compounds, Δ-protoilludene, β-barbatene, and an unidentified oxygenated sesquiterpene ( 218.18), changed production during co-cultivation with the ectomycorrhizal partner tree, , could be shown with distinct dynamics. During the mycorrhizal growth of -, Δ-protoilludene and the oxygenated sesquiterpene appeared at similar times, which warranted further studies of potential biosynthesis genes. In silico analyses identified a putative protoilludene synthesis gene, , as being up-regulated in the mycorrhizal stage, in addition to the previously identified, co-regulated geosmin synthase, . We therefore hypothesize that the sesquiterpene synthase has an important role during mycorrhization, through Δ-protoilludene and/or its accompanied oxygenated sesquiterpene production.