P-380 - Exploring Fusarium oxysporum colonization and host adaptation: global risks in plant health and disease

Fusarium oxysporum is a globally significant soilborne fungus that includes both devastating plant pathogens and nonpathogenic endophytes. While pathogenic isolates are well characterized, nonpathogenic strains remain largely unexplored, despite their critical role in plant-fungal interactions and potential implications for the evolution of pathogenicity. This study investigates the ecological and functional diversity of F. oxysporum, focusing on host adaptation in nonpathogenic isolates. Using the F. oxysporum f. sp. lycopersici-tomato system, we assessed colonization patterns via re-isolation, quantitative PCR, and confocal microscopy. Results reveal a spectrum of in planta activity suggesting that endophytic F. oxysporum isolates vary in their ability to colonize plants, providing key insights into the factors that may contribute to the emergence of pathogenic traits. Understanding how these fungi interact with their hosts is essential for unraveling the mechanisms driving pathogenicity and host adaptation. By advancing knowledge of plant-fungal interactions, this research informs strategies for disease management and contributes to global efforts to safeguard food security amid increasing agricultural threats. Understanding this continuum of host adaptation provides crucial insights into pathogen evolution and the potential for emerging risks in plant health.