[SCAN] Unveiling the Physiology of Aspergillus: Understanding its Role as Friend or Foe

Title: Unveiling the Physiology of Aspergillus: Understanding its Role as Friend or Foe

Speaker: João Jorge

From: Applied and Environmental Mycology, ITQB NOVA

Abstract: Aspergilli comprise a diverse group of saprophytic filamentous fungus covering over 200 million years of evolution. They have been extensively studied due to their biotechnological and ecological relevance and pathogenic potential. Earlier studies on the genome’s structure and evolution between aspergilli revealed an impressive level of structural and functional conservation and synteny. These high levels of genomic similarity in aspergilli underline the likely existence of conserved genes responsive to variable chemical stresses. In this study, we used a computational strategy to test the far-reaching hypothesis that exposure to organic compounds triggers unknown conserved responses across aspergilli. Specifically, five transcriptome-based datasets on exposure to organic compounds were used, covering three distinct Aspergillus species. Among the identified up-regulated genes, only one gene showed the same response in all conditions, AN9181. This gene encodes a protein containing a phenylcoumaran benzylic ether reductase-like domain and a Nitrogen metabolite repressor regulator domain (NmrA). Deletion of this gene caused significant phenotypic alterations compared to that of the parental strain across diverse conditions. Specifically, the deletion of AN9181 raised the mutant’s metabolic activity in different nitrogen sources. The acquired data supports that AN9181 acts by repressing (slowing down) A. nidulans growth when exposed to aromatic compounds in a concentration dependent manner. The same phenotype was observed for amphotericin B. Finally, AN9181 underwent differential upregulation under oxidative stress conditions. Collectively, the data suggest that AN9181, herein assigned as NmrB (Nitrogen Metabolite Repression Regulator B), builds up the genetic machinery of perception of oxidative stress by negatively regulating growth under such conditions.