Volume 20, Issue 8, Pages 1055-1066 (August 2013) Genetic Manipulation of the Fusarium fujikuroi Fusarin Gene Cluster Yields Insight into the Complex Regulation and Fusarin Biosynthetic Pathway  Eva-Maria Niehaus, Karin Kleigrewe, Philipp Wiemann, Lena Studt, Christian M.K. Sieber, Lanelle R. Connolly, Michael Freitag, Ulrich Güldener, Bettina Tudzynski, Hans-Ulrich Humpf  Chemistry & Biology  Volume 20, Issue 8, Pages 1055-1066 (August 2013) DOI: 10.1016/j.chembiol.2013.07.004 Copyright © 2013 Elsevier Ltd Terms and Conditions

Chemistry & Biology 2013 20, 1055-1066DOI: (10. 1016/j. chembiol. 2013 Copyright © 2013 Elsevier Ltd Terms and Conditions

Figure 1 Structures of Naturally Occurring Fusarins and the Fusarin C Gene Cluster (A) Fusarin C, fusarins D and A, epi-fusarin C, (10Z)-fusarin C, (8Z)-fusarin C, (6Z)-fusarin C, dihydrofusarin C, and open-chain fusarin C. (B) The fusarin genes fus1–fus9 are depicted as black boxes. The border genes (FFUJ_10049 and FFUJ_10059) are presented in gray. White bars show the positions of the introns, and the arrows indicate the direction of transcription. Chemistry & Biology 2013 20, 1055-1066DOI: (10.1016/j.chembiol.2013.07.004) Copyright © 2013 Elsevier Ltd Terms and Conditions

Figure 2 Regulation of Fusarin C (A) Coregulation of the putative fus gene cluster. The WT strain IMI58289 was grown for 2 days in either 6 mM glutamine (N−) or 60 mM glutamine (N+). The northern blot was hybridized with the putative fus genes (fus1–fus9) and the border genes FFUJ_10059 and FFUJ_10049 of the putative fusarin gene cluster. rRNA, ribosomal RNA. (B) Glutamine (gln) is needed for fusarin production and gene expression. HPLC-DAD measurement of the WT grown for seven days in 120 mM NaNO3 or 60 mM glutamine. Bars represent the SD of three independent biological repeats. WT was grown in 120 mM NaNO3 or 60 mM glutamine for 3 days for the northern blot. The hybridization was done with fus8; mAU, milliabsorbance unit. (C) The gene expression is influenced by pH and independent of the pH-regulator PacC. The WT and the ΔpacC strain were grown for 2 days in 60 mM glutamine. The mycelia were washed after harvesting and then shifted into N+ media appointed to pH 4 or pH 8. After 2 hr, the mycelia were harvested again. For probing of the northern blot fus3, fus7, and fus9 were used. (D) The biosynthetic gene cluster of fusarin C. The cluster of the fusarins consists of nine genes. ChIP-seq was conducted for the WT grown for 3 days under N− or N+ conditions. The fusarin cluster is enriched for the acetylation of histone 3 at lysine 9 (H3K9ac) under fusarin-favoring conditions. Chemistry & Biology 2013 20, 1055-1066DOI: (10.1016/j.chembiol.2013.07.004) Copyright © 2013 Elsevier Ltd Terms and Conditions

Figure 3 No Influence of the fus Gene Deletions on the Expression of the Remaining Genes WT and the single deletion mutants of the fus gene cluster, including the Δfus2-9 strain, were grown for 2 days in 60 mM glutamine. After harvesting, a northern blot was performed. The blot was hybridized with the indicated probes (fus1–fus9). See also Figures S2 and S3. Chemistry & Biology 2013 20, 1055-1066DOI: (10.1016/j.chembiol.2013.07.004) Copyright © 2013 Elsevier Ltd Terms and Conditions

Figure 4 Analysis of the WT and the Single fus1, fus2, fus8, fus9, and fus2-9 Deletion Strains The strains were grown for 4 days in 60 mM glutamine. Pictures of the individual strains and HPLC-UV measurement of the supernatant of the cultivated strains. The numbers in the chromatograms represent the compounds. 1, dihydrofusarin C; 2, epi-fusarin C; 3, fusarin C; 4, fusarin D; 5, 20-hydroxy-prefusarin C. Chemistry & Biology 2013 20, 1055-1066DOI: (10.1016/j.chembiol.2013.07.004) Copyright © 2013 Elsevier Ltd Terms and Conditions

Figure 5 Fusarin Production Could Be Restored via Cocultivation and Only fus1, fus2, and fus8 Are Required for Production of Carboxy-fusarin C (A) WT, Δfus1, and cocultivation of Δfus1 and Δfus2-9 were grown for 4 days in N+. The supernatant of the cultures was directly used for measurements with HPLC-DAD (1, dihydrofusarin C; 2, epi-fusarin C; 3, fusarin C; 4, fusarin D). (B) The strains were grown for 4 days in N+. The supernatants were measured via HPLC-MS, and the extracted masses at 363 nm are shown. Each approach showed production of the precursor of fusarin C: 6, carboxy-fusarin C. The deletion mutant of fus9 as a control, fus2, and fus8 are overexpressed in the background of the Δfus2-9 mutant (only fus1, fus2, and fus8 are expressed in this mutant), and cocultivation of the Δfus2-9/OE::fus2 and the Δfus2-9/OE::fus8 strains are shown. Chemistry & Biology 2013 20, 1055-1066DOI: (10.1016/j.chembiol.2013.07.004) Copyright © 2013 Elsevier Ltd Terms and Conditions

Figure 6 Identified Structures of the Supernatants of Knockout Mutants and the Proposed Fusarin Biosynthetic Pathway (A) Prefusarin, 20-hydroxy-prefusarin, decarboxy-fusarin C, and carboxy-fusarin C were found in the Δfus2-9, Δfus2, Δfus8, and the Δfus9 mutants, respectively. (B) After the PKS/NRPS forms prefusarin (7), the putative P450 mono-oxygenase Fus8 oxidizes at C-20 to form 20-hydroxy-prefusarin (5). After that, the putative multifunctional enzyme Fus2 is involved in the formation of the 2-pyrrolidone ring, the oxidation at C-15, and the epoxidation at C-13 and C-14 (20-hydroxy-fusarin, 8∗). Then, Fus8 oxidizes C-20 to form the carboxylic acid group (carboxy-fusarin C, 6). The last step is the methylation by the methyltransferase Fus9 of the hydroxyl group of C-21 to form fusarin C (3). See also Figures S4–S23. Chemistry & Biology 2013 20, 1055-1066DOI: (10.1016/j.chembiol.2013.07.004) Copyright © 2013 Elsevier Ltd Terms and Conditions