Abstract
Fungi produce numerous secondary metabolites (SMs), which possess various functions e.g. as communication signals during coexistence with other microorganisms. Many SM biosynthesis gene clusters are silent under standard laboratory conditions because their environmental or developmental triggers are unknown. Previously, we discovered that the silent orsellinic acid (ors) gene cluster in the filamentous fungus Aspergillus nidulans is activated upon interaction with the bacterium Streptomyces rapamycinicus and that this induction is dependent on the GcnE lysine-acetyltransferase catalyzing histone H3 acetylation. Here, we report a genome-wide analysis of chromatin acetylation changes during this interaction and relate these to changes in the fungal transcriptome. Our results reveal that only a functional interaction with S. rapamycinicus changes the chromatin landscape and activates amino acid cross-pathway control in the fungus. We identified the Myb-like transcription factor BasR as novel regulator required for bacteria-triggered SM production and show that its function is conserved in other Aspergillus species.