Abstract:
Terpenes represent the biggest group of natural compounds on earth. This large class of
organic hydrocarbons is distributed among all cellular organisms, including fungi. The different
classes of terpenes produced by fungi are mono, sesqui, di- and triterpenes, although triterpene
ergosterol is the main sterol identified in cell membranes of these organisms. The availability of
genomic data from members in the Ceratocystidaceae enabled the detection and characterization
of the genes encoding the enzymes in the mevalonate and ergosterol biosynthetic pathways. Using
a bioinformatics approach, fungal orthologs of sterol biosynthesis genes in nine different species
of the Ceratocystidaceae were identified. Ergosterol and some of the intermediates in the pathway
were also detected in seven species (Ceratocystis manginecans, C. adiposa, Huntiella moniliformis,
Thielaviopsis punctulata, Bretziella fagacearum, Endoconidiophora polonica and Davidsoniella virescens),
using gas chromatography-mass spectrometry analysis. The average ergosterol content differed
among different genera of Ceratocystidaceae. We also identified all possible terpene related genes
and possible biosynthetic clusters in the genomes used in this study. We found a highly conserved
terpene biosynthesis gene cluster containing some genes encoding ergosterol biosynthesis enzymes
in the analysed genomes. An additional possible terpene gene cluster was also identified in all of the
Ceratocystidaceae. We also evaluated the sensitivity of the Ceratocystidaceae to a triazole fungicide
that inhibits ergosterol synthesis. The results showed that different members of this family behave
differently when exposed to different concentrations of triazole tebuconazole.
