Identification of a Novel Biosynthetic Gene Cluster in Aspergillus niger Using Comparative Genomics

Abstract

Previously, DNA microarrays analysis showed that, in co-culture with <i>Bacillus subtilis</i>, a biosynthetic gene cluster anchored with a nonribosomal peptides synthetase of <i>Aspergillus niger</i> is downregulated. Based on phylogenetic and synteny analyses, we show here that this gene cluster, <i>NRRL3_00036-NRRL3_00042</i>, comprises genes predicted to encode a nonribosomal peptides synthetase, a FAD-binding domain-containing protein, an uncharacterized protein, a transporter, a cytochrome P450 protein, a NAD(P)-binding domain-containing protein and a transcription factor. We overexpressed the in-cluster transcription factor gene <i>NRRL3_00042</i>. The overexpression strain, NRRL3_00042^OE, displays reduced growth rate and production of a yellow pigment, which by mass spectrometric analysis corresponds to two compounds with masses of 409.1384 and 425.1331. We deleted the gene encoding the NRRL3_00036 nonribosomal peptides synthetase in the NRRL3_00042^OE strain. The resulting strain reverted to the wild-type phenotype. These results suggest that the biosynthetic gene cluster anchored by the <i>NRRL3_00036</i> nonribosomal peptides synthetase gene is regulated by the in-cluster transcriptional regulator gene <i>NRRL3_00042</i>, and that it is involved in the production of two previously uncharacterized compounds.