Comparative Genomics of Fusarium oxysporum f. sp. albedinis Reveals the Effector Repertoire and Molecular Arsenal for Date Palm Infection.

Background Fusarium oxysporum f. sp. albedinis (Foa) is a highly aggressive soilborne pathogen that poses a serious threat to date palm cultivation. Causal agent of the devastating palm dieback, also known as Bayoud disease, Foa remains one of the most destructive fungal pathogens threatening date palm sector across North Africa. Despite its economic and ecological impact, the molecular determinants underlying its virulence and host adaptation remain poorly understood. Results To address this gap, a comparative genomic and secretome analyses of four Foa strains was conducted, three newly sequenced Moroccan strains (ZG10, ER10, and ER20) and one publicly available reference genome (Foa133). The assembled genomes ranged from 58.81 to 61.24 Mb and encoded between 17,016 and 18,318 predicted protein-coding genes, of which approximately 27–30% were associated with pathogenicity. Functional annotation revealed an extensive repertoire of carbohydrate-active enzymes (CAZymes), particularly glycoside hydrolases, that facilitate host cell wall degradation and tissue colonization. Several key virulence effectors were identified, including Secreted in Xylem (SIX) proteins, necrosis-inducing proteins (NPP1s), and Hce2-like effectors, each potentially contributing to virulence, necrosis, and phytotoxicity. Additionally, genome mining uncovered multiple secondary metabolite biosynthetic clusters encoding polyketides and mycotoxins, suggesting a complementary toxin-mediated infection strategy. Conclusion These findings provide a solid genomic insight into Foa’s pathogenic potential and molecular complexity. By delineating the genetic basis of virulence and metabolic diversity, this study establishes a foundation for the development of molecular diagnostics, targeted disease management strategies, and breeding programs aimed at enhancing date palm resistance to Bayoud disease.