Chrysogine Biosynthesis Is Mediated by a Two-Module Nonribosomal Peptide Synthetase

Production of chrysogine has been reported from several fungal genera including <i>Penicillium</i>, <i>Aspergillus</i>, and <i>Fusarium</i>. Anthranilic acid and pyruvic acid, which are expected precursors of chrysogine, enhance production of this compound. A possible route for the biosynthesis using these substrates is via a nonribosomal peptide synthetase (NRPS). Through comparative analysis of the <i>NRPSs</i> from genome-sequenced producers of chrysogine we identified a candidate <i>NRPS</i> cluster comprising five additional genes named <i>chry2</i>–6. Deletion of the two-module <i>NRPS</i> (<i>NRPS14</i> = <i>chry1</i>) abolished chrysogine production in <i>Fusarium graminearum</i>, indicating that the gene cluster is responsible for chrysogine biosynthesis. Overexpression of <i>NRPS14</i> enhanced chrysogine production, suggesting that the NRPS is the bottleneck in the biosynthetic pathway