Integração de Metabolômica, Redes Moleculares e Co-Cultura para a Produção de Metabólitos Secundários em Fungos Endofíticos: Potenciais aplicações contra Fitopatógenos e Bactérias Patogênicas

Abstract

Endophytic fungi are promising sources of bioactive secondary metabolites with potential to combat both agricultural phytopathogens and antibiotic-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), a significant problem of public health. These microorganisms produce compounds in monocultures or co-cultures, which can enhance the production of bioactive metabolites and increase chemical diversity. The co-culture technique, involving the simultaneous cultivation of different microorganisms, has proven effective in activating cryptic genes, thereby increasing chemical diversity and the production of metabolites related to microbial defense and communication. In the present study, two cultivation approaches were undertaken to explore the potential of endophytic fungi in producing secondary metabolites with biological activity against pathogenic microorganisms. Initially, five endophytic fungi, Penicillium cataractarum 5IP2F4, Aspergillus sp. 6IP2F3, Pestalotiopsis sp. 6MP2F4, Pestalotiopsis sp. 6IP2F1, and Aspergillus fijiensis 1IP2F1, isolated from Bromelia balansae (Bromeliaceae), were cultivated in monocultures on submerse media with potato dextrose broth and their extracts were investigated for their antibacterial and antibiofilm activities against MRSA and Pseudomonas aeruginosa. Extracts were analyzed using High-Performance Liquid Chromatography coupled to Diode-Array Detection and Mass Spectrometry (HPLC-DAD-MS), which the data were applied to obtain the molecular network, and their compounds were annotated. The broth (CEbro) and mycelial (CEmyc) extracts of Aspergillus fijiensis 1IP2F1 (AsFi1I) exhibited antibacterial properties against MRSA, showing inhibitions of bacterial growth by 63.9% to 70.2%, and biofilm formation by 72.8% to 97.7%, respectively. Metabolites such as asperparaline A, oxaline, sesterterpenoids, and dimeric xanthones were annotated from these samples. Simultaneously, the effects of co-culture on the biosynthesis of secondary metabolites in P. cataractarum (PC) were also explored. This endophytic fungus, P. cataractarum (PC), was co-cultivated with the phytopathogen Sclerotinia sclerotiorum (SS) on solid medium (potato, dextrose, and agar) to assess the metabolic changes induced by this interaction and its impact on secondary metabolite production. Compounds observed via HPLC-DAD-MS were analyzed, and principal component analysis (PCA) revealed chemical changes when compared different regions of the confrontation, as well as observed in controls. Co-cultivation induced the upregulation of certain metabolites, including the production of three metabolites (m/z 393.0140, 279.0991, and 435.1522). These findings underscore the potential of co-culture as a powerful tool to enhance the production of secondary metabolites, providing insights into microbial interactions and offering new avenues for developing antibacterial agents and strategies for agricultural pest control. This study highlights the relevance of endophytic fungi in the production of secondary metabolites with potential for novel therapeutic applications. The analysis of isolated strains and the co-culture technique demonstrated the ability of these organisms to generate bioactive compounds and explore new biosynthetic pathways. These results emphasize the importance of continuing research on endophytic fungi to pursue innovative solutions for the development of therapeutic agents and pest control strategies.