Phosphopantetheinyl Transferase NpgA for the Sterigmatocystin Biosynthesis in the filamentous fungus Aspergillus nidulans

Post-translational modification of 4′-phosphopantetheinyl transferase (PPTase) is essential for the biosynthesis of primary and secondary metabolites in fungi. In this study, we investigated genes associated with the npgA gene, encoding 4’-phosphopantetheinyl transferase (PPTase), within both wild-type and npgA1 mutant strains of A. nidulans. Some genes, which are associated with sterigmatocystin biosynthesis, were explored comprehensive analyses, including transcriptomics, proteomics, and two-hybrid techniques. Selected genes were further subjected to quantitative reverse transcription polymerase chain reaction (qRT-PCR) and thin-layer chromatography (TLC) analyses. A. nidulans harboring the npgA1 mutation failed to produce either ST or its intermediates. These findings suggests that defective NpgA compromises ST biosynthesis, which is reliant on the ST polyketide synthase. Our results support the NpgA PPTase as a novel and promising target for antifungal drug development, as its inhibition stands to disrupt the production of melanin and other critical virulence factors associated with pathogenicity.