title: 6-MSAS-like polyketide synthase genes occur in lichenized ascomycetes.
abstract: Lichenized and non-lichenized filamentous ascomycetes produce a great variety of polyketide secondary metabolites. Some polyketide synthase (PKS) genes from non-lichenized fungi have been characterized, but the function of PKS genes from lichenized species remains unknown. Phylogenetic analysis of keto synthase (KS) domains allows prediction of the presence or absence of particular domains in the PKS gene. In the current study we screened genomic DNA from lichenized fungi for the presence of non-reducing and 6-methylsalicylic acid synthase (6-MSAS)-type PKS genes. We developed new degenerate primers in the acyl transferase (AT) region to amplify a PKS fragment spanning most of the KS region, the entire linker between KS and AT, and half of the AT region. Phylogenetic analysis shows that lichenized taxa possess PKS genes of the 6-MSAS-type. The extended alignment confirms overall phylogenetic relationships between fungal non-reducing, 6-MSAS-type and bacterial type I PKS genes.
authors.affiliation: Department of Botany, The Field Museum, 1400 South Lake Shore Drive, Chicago, IL 60605, USA. schm2109@umn.edu
authors.forename: Imke
authors.initials: I
authors.lastname: Schmitt
authors.forename: Stefanie
authors.initials: S
authors.lastname: Kautz
authors.forename: H Thorsten
authors.initials: HT
authors.lastname: Lumbsch
mesh_terms: D000217:Acyltransferases / Q000737:chemistry / Q000235:genetics*; D000595:Amino Acid Sequence; D001203:Ascomycota / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D001419:Bacteria / Q000201:enzymology / Q000235:genetics; D004271:DNA, Fungal / Q000032:analysis / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics; D016681:Genome, Fungal; D008011:Lichens / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D008025:Ligases / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry / Q000235:genetics*; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics*; D010802:Phylogeny; D048630:Polyketide Synthases / Q000737:chemistry / Q000235:genetics*; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D009097:Multienzyme Complexes; D048630:Polyketide Synthases; D010088:Oxidoreductases; D000217:Acyltransferases; C021587:6-methylsalicylic acid synthetase; D008025:Ligases