Cloning and heterologous transcription of a polyketide synthase gene from the lichen Solorina crocea

• Published in: Mycological research 2009-03, Vol.113 (3), p.354-363
• Main Authors: Gagunashvili, Andrey N., Davíðsson, Snorri P., Jónsson, Zophonías O., Andrésson, Ólafur S.
• Format: Article
• Language: English
• Subjects: alternapyrone; Amino Acid Sequence; amino acid sequences; Ascomycetes; Ascomycota - enzymology; Ascomycota - genetics; Aspergillus oryzae; Aspergillus oryzae - genetics; carbon-carbon bond ligases; Cloning, Molecular; fungal proteins; Fungal Proteins - genetics; Fungal Proteins - metabolism; gene expression regulation; Genes, Fungal - genetics; genetic transformation; Lichen; lichens; Lichens - enzymology; Lichens - genetics; Macrolides - chemistry; Macrolides - metabolism; molecular cloning; Molecular Sequence Data; polyketide synthase; Polyketide synthases; Polyketide Synthases - genetics; Polyketide Synthases - metabolism; Polyketides; Secondary metabolites; Sequence Alignment; sequence analysis; Solorina; Solorina crocea; squalestatin; transcription (genetics); Transcription, Genetic
• ISSN: 0953-7562; 1469-8102
• DOI: 10.1016/j.mycres.2008.11.011

Lichens and most ascomycete fungi produce polyketide secondary metabolites often with valuable biological activities. Their biosynthesis is primarily governed by large iterative multifunctional type I polyketide synthases. Although there has been good progress studying filamentous non-lichenized fungi, there is limited information on polyketide biosynthesis in lichens and their mycobionts, due to their slow growth, difficulties in establishing pure cultures, and the absence of methods for direct genetic manipulation. However, heterologous expression in a surrogate host offers an alternative approach for exploring lichen polyketide biosynthesis. Here, we report cloning of a type I polyketide synthase gene from the foliose lichen Solorina crocea and its heterologous transcription in the filamentous fungus Aspergillus oryzae, including processing of the transcript. No new polyketide product was detected. The lichen polyketide synthase showed greatest homology with uncharacterized genes from filamentous fungi and lower homology with proteins catalysing biosynthesis of the decaketide alternapyrone and the tetraketide side-chain of squalestatin. The technology platform utilized here presents a useful tool for functional characterization of fungal biosynthetic genes and provides a means for novel production of valuable compounds.