title: Establishment of the Inducible Tet-On System for the Activation of the Silent Trichosetin Gene Cluster in Fusarium fujikuroi.
abstract: The PKS-NRPS-derived tetramic acid equisetin and itsN-desmethyl derivative trichosetin exhibit remarkable biological activities against a variety of organisms, including plants and bacteria, e.g.,Staphylococcus aureus. The equisetin biosynthetic gene cluster was first described inFusarium heterosporum, a species distantly related to the notorious rice pathogenFusarium fujikuroi. Here we present the activation and characterization of a homologous, but silent, gene cluster inF. fujikuroi. Bioinformatic analysis revealed that this cluster does not contain the equisetinN-methyltransferase geneeqxDand consequently, trichosetin was isolated as final product. The adaption of the inducible, tetracycline-dependent Tet-on promoter system fromAspergillus nigerachieved a controlled overproduction of this toxic metabolite and a functional characterization of each cluster gene inF. fujikuroi. Overexpression of one of the two cluster-specific transcription factor (TF) genes,TF22, led to an activation of the three biosynthetic cluster genes, including thePKS-NRPSkey gene. In contrast, overexpression ofTF23, encoding a second Zn(II)₂Cys₆ TF, did not activate adjacent cluster genes. Instead,TF23was induced by the final product trichosetin and was required for expression of the transporter-encoding geneMFS-T. TF23 and MFS-T likely act in consort and contribute to detoxification of trichosetin and therefore, self-protection of the producing fungus.
authors.affiliation: Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-Universität Münster, Schlossplatz 8, 48143 Münster, Germany. slavica.janevska@uni-muenster.de.
authors.forename: Slavica
authors.initials: S
authors.lastname: Janevska
authors.affiliation: Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstrasse 45, 48149 Münster, Germany. birgit.arndt@uni-muenster.de.
authors.forename: Birgit
authors.initials: B
authors.lastname: Arndt
authors.affiliation: Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-Universität Münster, Schlossplatz 8, 48143 Münster, Germany. leoniebaumann@gmx.com.
authors.forename: Leonie
authors.initials: L
authors.lastname: Baumann
authors.affiliation: Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-Universität Münster, Schlossplatz 8, 48143 Münster, Germany. l_apke01@uni-muenster.de.
authors.forename: Lisa Helene
authors.initials: LH
authors.lastname: Apken
authors.affiliation: Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstrasse 45, 48149 Münster, Germany. lucasmauriz@yahoo.com.br.
authors.forename: Lucas Maciel
authors.initials: LM
authors.lastname: Mauriz Marques
authors.affiliation: Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstrasse 45, 48149 Münster, Germany. humpf@uni-muenster.de.
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Humpf
authors.affiliation: Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-Universität Münster, Schlossplatz 8, 48143 Münster, Germany. tudzynsb@uni-muenster.de.
authors.forename: Bettina
authors.initials: B
authors.lastname: Tudzynski
mesh_terms: D001230:Aspergillus / Q000235:genetics; D002470:Cell Survival / Q000187:drug effects; D005656:Fungal Proteins / Q000235:genetics; D005670:Fusarium / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D056945:Hep G2 Cells; D006801:Humans; D005810:Multigene Family; D012275:Oryza / Q000382:microbiology; D010935:Plant Diseases / Q000382:microbiology; D011401:Promoter Regions, Genetic; D011760:Pyrrolidinones / Q000302:isolation & purification / Q000378:metabolism / Q000633:toxicity; D013764:Tetrahydronaphthalenes / Q000633:toxicity; D014157:Transcription Factors / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D011760:Pyrrolidinones; D013764:Tetrahydronaphthalenes; D014157:Transcription Factors; C465303:trichosetin; C024509:equisetin
keywords: Fungi; Fusarium fujikuroi; PKS-NRPS; biosynthesis; gene regulation; secondary metabolism