Molecular biological and biochemical investigations of the biosynthesis of mycotoxins in ascomycota

Marco Matuschek, Pharmazeutische Biologie, Li, Shu-Ming (Prof. Dr. )
Fungi are rich sources of secondary metabolites. Among these secondary metabolites, the ergot alkaloids are both pharmaceutically useful and toxic. Ergot alkaloids are indole derivatives produced by fungi of the genera Claviceps, Aspergillus and Penicillium with Claviceps purpurea (C. purpurea) as the most important producer for medical use. C. purpurea produces ergotamine and ergocryptine as main ergot alkaloids. The clavine-type alkaloids, e.g. festuclavine, pyroclavine and fumigaclavines A,
more » ... and C are mainly produced by the fungi Aspergillus fumigatus (A. fumigatus) and Penicillium commune (P. commune). Chanoclavine-I-aldehyde is a branch point of ergot alkaloid biosynthesis for ergotamine in C. purpurea and fumigaclavines C and A, respectively in A. fumigatus and P. commune. Ergotamine is characterized by a peptide moiety which is absent in the fumigaclavines. Instead, the fumigaclavines contain additional substituents, e.g. alcohol or acetoxy group at C-9 and a reverse prenyl moiety at C-2. Furthermore, the C-8 stereochemistry of fumigaclavine C from A. fumigatus and fumigaclavine A from P. commune differs. In this study, the presence of genes for ergot alkaloid biosynthesis in ascomycetous fungi was investigated. For this purpose, 138 available genomes of 53 fungi families of the NCBI database were screened with the sequences of the seven orthologous genes from C. purpurea and A. fumigatus. 23 ascomycetous fungi belonging to the families Trichocomaceae, Clavicipitaceae and Arthrodermataceae were identified to contain putative ergot alkaloid gene clusters. The family Clavicipitaceae is assigned to the class of Sordariomycetes, whereas the families Trichocomaceae and Arthrodermataceae are members of the class of Eurotiomycetes. The two identified fungi of the genus Metarhizium belong to the family Clavicipitaceae. Until [...]
doi:10.17192/z2012.0508 fatcat:sc2ay3spajc4rnogxqo6j6abqe