Exudates secreted: Penicillium expansum's means of conquering the external environment
Year: 2025
Type: article
Abstract: Penicillium expansum , the causal agent of apple blue rot, produces patulin, a well-known mycotoxin regulated in many countries. When grown on various synthetic media, P. expansum secretes exudates. The release of the latter has been previously described in fungi and contribute to their virulence by secreting toxic specialized metabolites (SMs) into the external environment. Exudates are no longer produced in a mutant deleted for PatL, a transcription factor essential for patulin biosynthesis, suggesting a link between patulin and exudate production. In this context, the content of exudates produced by P. expansum was characterized by metabolomics and proteomics. These analyses revealed 20 SMs such as patulin and citrinin, and 194 proteins in the secretome, mainly involved in carbohydrate metabolism to degrade the plant wall, and to build or modify the fungal wall. Four of the secreted proteins (PatE, PatB, PatO, PatF) are involved in patulin biosynthesis, especially PatE, the last enzyme in the patulin biosynthetic pathway. The fact that its substrate, ascladiol, was also present suggests that the final step of patulin secretion may occur outside the fungus. In parallel, a comparative transcriptomic study of wild-type and null mutant Δ patL strains unveiled that PatL negatively or positively regulated the expression of 294 genes. Among them, 21 genes encode proteins present in exudates, i.e. 11 % of the exudates, including four proteins involved in patulin biosynthesis, but also enzymes involved in starch degradation. Our results suggest a broader role for PatL than the sole regulation of patulin biosynthesis. • Identification of metabolites and proteins in Penicillium expansum exudates. • Exudates contain the mycotoxins patulin and its precursor ascladiol. • The secretome proteins include CAZymes and PatB, PatE, PatF, and PatO. • PatL plays a key role in exudate composition in P. expansum. • Pat L regulates genes outside the patulin cluster.
Institutions: École Nationale Vétérinaire de Toulouse, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Ecole d'Ingénieurs de PURPAN, Toxicologie Alimentaire, Université de Toulouse, Centre National de la Recherche Scientifique, Université Toulouse III - Paul Sabatier, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Institut de Recherche Interdisciplinaire de Grenoble, Institut de Pharmacologie et de Biologie Structurale, Fédération de Recherche Agrobiosciences, Interactions et Biodiversité, Aix-Marseille Université, Architecture et Fonction des Macromolécules Biologiques, Technical University of Denmark, Institut National Polytechnique de Toulouse, Laboratoire de Génie Chimique
Language: English
Subfield: Plant Science
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $4,280
OpenAlex ID: W4410021434