Tricholoma vaccinum 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
6-protoilludene, β-barbatene, and an
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Tricholoma vaccinum 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
6-protoilludene, β-barbatene, and an unidentified oxygenated sesquiterpene (
m/z 218.18), changed production during co-cultivation with the ectomycorrhizal partner tree,
Picea abies, could be shown with distinct dynamics. During the mycorrhizal growth of
T. vaccinum–
P. abies, Δ
6-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,
pie1, as being up-regulated in the mycorrhizal stage, in addition to the previously identified, co-regulated geosmin synthase,
ges1. We therefore hypothesize that the sesquiterpene synthase
pie1 has an important role during mycorrhization, through Δ
6-protoilludene and/or its accompanied oxygenated sesquiterpene production.
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