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Description
Date palm (Phoenix dactylifera L.) is a crop of major importance in the Moroccan economy and ecosystem. In desert oases, date palm trees create a friendly microclimate environment suitable for cultivating legume crops and protecting lands from desertification. The fungus Fusarium oxysporum f. sp. albedinis (Foa), the causal agent of bayoud disease, is the most alerting pathogen that infects and causes heavy damage to the date palms. A promising approach for the eco-friendly management of plant diseases is the use of biocontrol agents (BCAs). Among these, Bacillus sp. are widely known as BCAs against plant pathogens and are reputed for their resilience in different types of environments. This present study aims to recover, from Moroccan soils, potential Bacillus BCAs against the fungal pathogen Foa. The heat-shock treatment of collected samples associated with the Gram staining and microscopic observation was conducted to isolate the spore-forming bacteria Bacillus sp.. A total of 513 isolates have been recovered from the different sampled soils. For the in vitro antagonistic preselection tests, a total of 20 isolates were confronted in dual culture assays with Foa to assess their potential to inhibit fungal growth. Three (03) isolates showed the most effective inhibition of the pathogen mycelial development ranging between 72% to 76%. These isolates were molecularly characterized by sequencing their 16S regions and were identified as Bacillus haynessi NRRL B-41327, Bacillus velezensis strain CBMB205, and Bacillus velezensis strain FZB42. Our results highlight the potential of Moroccan soils for developing native BCAs with the potential of controlling bayoud disease and to our knowledge, the species Bacillus haynessi has never been reported as a BCAs.
