Evaluation de l’activité antifongique et enzymatique des champignons endophytes associés à des algues marines

Abstract

In response to the impacts of chemical fungicides, biological control is emerging as a sustainable alternative for crop protection. This work aims to evaluate the enzymatic potential and antagonistic activity of four marine endophyte strains against phytopathogens affecting faba bean (Vicia faba L.) and loquat (Eriobotrya japonica L.). The approach involved isolating and identifying phytopathogenic agents from symptomatic plant samples collected in Mostaganem. Concurrently, the enzymatic profile of four endophyte strains (Aspergillus niger AL6.1, Aspergillus terreus B02H, Penicillium chrysogenum CR2, and Penicillium sp. UR3) was evaluated on specific solid media. Antifungal activity was then investigated in vitro through direct confrontation and disk diffusion assays using crude secondary metabolite extracts, which were obtained after ethyl acetate extraction of the liquid fermentation medium. The pathogenic isolates Alternaria sp. (FB1, NJ) and Botrytis sp. (FB2) were identified. Screening revealed that strain AL6.1 (A. niger) possessed the most important enzymatic profile and the best performance in direct confrontation, achieving 61.11% radial inhibition against isolate NJ. Conversely, crude extracts from Penicillium strains (CR2 and UR3) showed the highest efficacy by diffusion, causing broad inhibition zones against Botrytis sp. Spores (up to 20.7 ± 1.2 mm). These findings highlighted the promising potential of marine endophytes for biological control in agriculture, through the dual efficacy of their extracellular enzyme systems and secondary metabolites against phytopathogens.