Understanding stress responses and signaling pathways in fungi became a fundamental need for the discovery of new specific antifungal targets for fighting emerging life-threatening pathogens and drug resistance. Ionic liquids constitute a unique class of chemicals, which structural diversity and tunable physical and chemical properties can provide a great diversity of stimuli. In this study, we propose the use of ionic liquids as tools to unravel signaling of stress responses in the filamentous fungus Aspergillus nidulans . We assessed how three ionic liquids with distinct effects over the cell wall and plasma membrane affect the biosynthesis of sphingolipids and accumulation of free sphingoid bases in this fungus. The stress imposed by each ionic liquid triggered the sphingolipid biosynthetic pathway and led to distinct profiles of sphingoid bases accumulation. Dodecyltributylphosphonium chloride and 1-decyl-3-methylimidazolium chloride induced the accumulation of sphingosine and of a yet unknown sphingoid base, respectively, while cholinium decanoate did not seem to accumulate any of these intermediates. This study brings further light to the roles of sphingoid bases in A. nidulans . In particular, sphingosine as a possible response mediator to cell wall damage induced by dodecyltributylphosphonium chloride, and involvement of an unknown sphingoid base in the response to plasma membrane permeabilization caused by 1-decyl-3-methylimidazolium chloride. In addition, we completed the genetic assignment of the glucosylceramide pathway in A. nidulans through the identification of the sphingolipid Δ4-desaturase gene ( AN4405 ). The knowledge established reinforces the idea of targeting sphingolipids biosynthesis in the search of improved antifungal compounds.

Fungi colonizing soil and organic pollutants often meet. The consequences of this encounter constitute an outstanding question.

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Background Organic pollutants are omnipresent and can penetrate all environmental niches. We evaluated the hypothesis that short-term (acute) exposure to aromatic hydrocarbon pollutants could increase the potential for fungal virulence. We analysed whether pentachlorophenol and triclosan pollution results in the production of airborne fungal spores with greater virulence than those derived from an unpolluted (Control) condition. Results Each pollutant altered the composition of the community of airborne spores, favouring an increase in strains with higher in vivo infection capacity (wax moth Galleria mellonella used as infection model). Fungi subsisting inside larvae, 72h post-infection and arising from either airborne spore-inoculum, exhibited comparable diversity (mainly within Aspergillus fumigatus). Several virulent Aspergillus strains were isolated from larvae infected with the airborne spores produced in a polluted environment. Meanwhile, strains isolated from the control, including one A. fumigatus strain, showed no virulence. Potential pathogenicity increased when two Aspergillus spp. virulent strains were assembled, suggesting the existence of synergisms that impact pathogenicity. None of the observed taxonomic or functional traits could separate the virulent from the avirulent strains. Conclusions Our study emphasises pollution-stress as a possible driver of phenotypic adaptations that increase Aspergillus spp. pathogenicity as well as the need to better understand the interplay between pollution and fungal virulence.