title: Alterations in secondary metabolism of aposymbiotically grown mycobionts of Xanthoria elegans and cultured resynthesis stages.
abstract: HPLC analyses of Xanthoria elegans cultivated on different media and either aposymbiontically or with its photobiont revealed that the carbon source and the presence of the algal partner have an impact on the secondary metabolism of the mycobiont. The aposymbiotically (without photobiont) grown mycobiont contained up to 70% more of the main compounds in its thallus than in resynthesis stage. Although this is speculative, the induction of the polyketide pathway may be a feedback mechanism to the absence of the photobiont. All cultures produce a variety of substances which were not detectable in the voucher specimen. Besides physcion (the major substance), we were able to identify emodin as well as physcion-bisanthrone, teloschistin monoacetate and derivatives. A strong inducible effect on the production of physcion, physcion-bisanthrone and on their precursors and derivatives was found for mannitol. By contrast, supplementation of ribitol had negligible effects, if any, on polyketide quantities although it is the main carbon source for the mycobiont in free-living lichens with Trebouxia photobiont.
authors.affiliation: Department of Organismic Biology, University of Salzburg, Hellbrunnerstrasse 34, Salzburg 5020, Austria. georg.brunauer@sbg.ac.at
authors.forename: Georg
authors.initials: G
authors.lastname: Brunauer
authors.forename: Armin
authors.initials: A
authors.lastname: Hager
authors.forename: Martin
authors.initials: M
authors.lastname: Grube
authors.forename: Roman
authors.initials: R
authors.lastname: Türk
authors.forename: Elfie
authors.initials: E
authors.lastname: Stocker-Wörgötter
mesh_terms: D000085:Acetates / Q000737:chemistry; D000873:Anthracenes / Q000737:chemistry; D001203:Ascomycota / Q000378:metabolism*; D002244:Carbon / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003470:Culture Media; D004247:DNA / Q000737:chemistry; D018744:DNA, Plant / Q000737:chemistry; D004642:Emodin / Q000031:analogs & derivatives / Q000737:chemistry; D008011:Lichens; D008353:Mannitol / Q000737:chemistry; D010641:Phenotype; D010940:Plant Proteins / Q000737:chemistry; D017422:Sequence Analysis, DNA; D013559:Symbiosis
chemical_list: D000085:Acetates; D000873:Anthracenes; D003470:Culture Media; D018744:DNA, Plant; D010940:Plant Proteins; D008353:Mannitol; D002244:Carbon; D004247:DNA; C008905:physcione; D004642:Emodin