Deciphering the early events of the transcriptional dialogue between Aspergillus fumigatus and Pseudomonas aeruginosa in a dual-species biofilm

This study employs dual-species RNA sequencing to decipher the early (48-hour) transcriptional dialogue within a co-culture biofilm model. We reveal that P. aeruginosa adopts a profound state of metabolic arrest and nutrient scavenging when confronted with wild-type A. fumigatus, characterized by a paradoxical downregulation of iron acquisition machinery and a global shift towards transport activity and alternative nutrient catabolism.

In response, A. fumigatus exhibits metabolic repression coupled with the induction of stress defense and alternative energy pathways. Disruption of the fungal histidine kinase SlnA, a key signaling component, dramatically alters this interkingdom crosstalk. In the presence of the ΔslnA mutant, P. aeruginosa reactivates canonical starvation responses, including siderophore production and chemotaxis, while the mutant fungus fails to mount an appropriate structural and chemical defense, displaying a transcriptional profile of dysregulated metabolism and vulnerability.