The dual nature of Fusarium oxysporum Fo47: from plant disease suppression to potential pathogenicity risks.

Fungal diseases threaten crop productivity, and the limitations of intensive fungicide use highlight the need for sustainable plant protection strategies. The non-pathogenic, endophytic strain Fusarium oxysporum Fo47 is one of the best-characterized models of disease-suppressive fungi. This review summarizes current knowledge on Fo47 as a beneficial endophyte and biological control agent, while also considering biosafety concerns related to the horizontal transfer of pathogenicity determinants. Fo47-mediated protection involves direct mechanisms, including competition, antibiosis and physical interference with pathogens, as well as indirect plant-mediated responses such as endophyte-mediated resistance and priming. Fo47 colonization may modulate PR proteins, ROS and antioxidant metabolism, cell wall remodeling, secondary metabolism and hormone-related signaling. However, these responses depend on the host plant, pathogen species and timing of application. Therefore, Fo47 represents a valuable model for endophyte-mediated disease suppression, but its broader agricultural use requires careful risk assessment. This review focuses primarily on evidence from tomato, pepper and flax pathosystems, while also incorporating findings reported in several other plant hosts.