Whole genome analysis of antagonistic and plant growth promoting Bacillus halotolerans KFD uncovers its molecular arsenal against the bayoud pathogen Fusarium oxysporum f.sp albedinis

• Identification of novel Bacillus halotolerans strain with biocontrol activities. • The strain showed high antifungal activities against different fungal pathogens. • The strain showed protective effect on date palm against the bayoud disease. • Comparative genomics showed that the strain harbored unique antifungal genes. • First report of Bacillus halotolerans biocontrol agents isolated from date palm. The bayoud disease stands as a serious threat to date palm cultivation and production in North Africa, particularly in Morocco. Biocontrol agents constitute an eco-friendly alternative solution to this problem, as breeding techniques or the use of chemical pesticides did not yield promising results, leading farmers to burn infected trees to limit the pathogen propagation. In this frame, we screened different bacteria isolated from date palm root surface for their potential to inhibit the pathogen F. oxysporum f.sp. albedinis (Foa). Out of forty tested isolates, one isolate showed promising results against Foa and exhibited as well broad-spectrum antifungal properties. Moreover, this isolate showed plant growth promotion (PGP) traits. We also conducted a greenhouse assay to evaluate the protective effect of our isolate. The result showed that our isolate effectively protected date palm seedlings against Foa. The genome characterization showed that our isolate has a genome size of approximately 3.9 MB and belongs to Bacillus halotolerans . We annotated 11 secondary metabolite gene clusters encompassing six known antifungal clusters, namely bacillibactin, bacilysin, bacillaene, fengycin, surfactin, and plipastatin. Moreover, we identified genes that encode carbohydrate-active enzymes involved in chitinase activities as well as the degradation of glucan in fungal cell walls. The screening of genes linked to plant growth promotion identified genes involved in phosphate metabolism, IAA and siderophore production , and free nitrogen fixation. Our results show that B. halotolerans KFD represents a potential biocontrol agent that could be used to manage bayoud disease and promote the growth of date palm. To the best of our knowledge, our study is the first to isolate and decipher the genomic features of a B. halotolerans strain from the rhizosphere of date palm.