The bZIP Transcription Factor AtfA Coordinates Asexual Sporulation with Primary Metabolism in Aspergillus nidulans

Asexual sporulation (conidiogenesis) in filamentous fungi is a complex developmental process that requires precise coordination with primary metabolism and environmental stress responses. In the model fungus Aspergillus nidulans, we demonstrate that the bZIP-type transcription fac-tor AtfA plays a central role in integrating conidiogenesis with the underlying metabolic and regulatory networks. Using combined ChIP-seq and RNA-seq analyses in wild-type, ?atfA, and atfA-complemented strains under stress-free and oxidative stress (menadione) conditions, we identify a conserved AtfA binding motif and map its functional targets genome-wide. Our data reveal that AtfA binding to its target promoters is largely stress-independent, suggesting a preemptive regulatory mechanism in conidial development. AtfA directly controls genes in-volved in the MAPK signaling cascade, light-dependent sporulation, antioxidant defense, ei-sosome biogenesis, and the biosynthesis of trehalose and polyols—key metabolites supporting spore maturation and dormancy. Importantly, AtfA acts predominantly as a transcriptional acti-vator, and its regulatory scope extends beyond stress adaptation to the orchestration of metabolic processes essential for spore integrity and germination. These findings position AtfA as a master regulator that synchronizes morphological development with metabolic preparedness during asexual reproduction in A. nidulans. Overall design: ChIP-seq was performed to map the binding sites of the AtfA transcription factor in the filamentous fungus Aspergillus nidulans. Analyses were carried out in untreated 2- and 3-day-old spores, as well as in 3-day-old spores exposed to menadione.