Endophytic Fusarium isolates from Ceratozamia mirandae enhance tomato growth, suppress pathogenic fungi, and induce protection against Botrytis cinerea

Fungal diseases in agricultural crops cause economic losses, with chemical control being the conventional method to manage them. However, this approach negatively impacts both the environment and human health. This study focused on endophytic fungi isolated from the roots of Ceratozamia mirandae in the Mexican locality of Juan Sabines (Villa Corzo, Chiapas). These fungi were identified morphologically and molecularly, biochemically characterized, and evaluated for their antagonistic activity against Colletotrichum karstii, Neopestalotiopsis sp. and Fusarium oxysporum. Their potential for promoting growth in Arabidopsis thaliana and tomato, as well as protecting against Botrytis cinerea, was also assessed. Fourteen fungal isolates were identified and grouped into six genera: Fusarium, Pestalotiopsis, Trichoderma, Umbelopsis, Nectria and Podospora. Among these Fusarium proliferatum JS311 and F. oxysporum JS239 exhibited strong inhibitory effects against the tested pathogens. Eight isolates were found to produce indole-3-acetic acid, promoting the growth of A. thaliana and tomato plants. Notably, F. oxysporum JS439 and F. solani (JS240, JS256 and JS4101) exhibited additional capabilities, including siderophore production and growth in nitrogen-free media. All Fusarium endophytic isolates induced systemic resistance against B. cinerea in tomato. Endophytic fungi from C. mirandae show promising potential as biofertilizers due to their combined mechanisms of anti-phytopathogenic activity, plant growth promotion, and systemic resistance induction through the production of beneficial metabolites.