The GATA-Type Transcription Factor Csm1 Regulates Conidiation and Secondary Metabolism in .

GATA-type transcription factors (TFs) such as the nitrogen regulators AreA and AreB, or the light-responsive TFs WC-1 and WC-2, play global roles in fungal growth and development. The conserved GATA TF NsdD is known as an activator of sexual development and key repressor of conidiation in , and as light-regulated repressor of macroconidia formation in In the present study, we functionally characterized the NsdD ortholog in , named Csm1. Deletion of this gene resulted in elevated microconidia formation in the wild-type (WT) and restoration of conidiation in the non-sporulating velvet mutant Δ demonstrating that Csm1 also plays a role as repressor of conidiation in . Furthermore, biosynthesis of the PKS-derived red pigments, bikaverin and fusarubins, is de-regulated under otherwise repressing conditions. Cross-species complementation of the Δ mutant with the ortholog led to full restoration of WT-like growth, conidiation and pigment formation. In contrast, the rescued only the defects in growth, the tolerance to HO and virulence, but did not restore the light-dependent differentiation when expressed in the Δ mutant. Microarray analysis comparing the expression profiles of the WT and the Δ mutant under different nitrogen conditions revealed a strong impact of this GATA TF on 19 of the 47 gene clusters in the genome of . One of the up-regulated silent gene clusters is the one containing the sesquiterpene cyclase-encoding key gene Heterologous expression of in enabled us to identify the product as the volatile bioactive compound (-)-germacrene D.