Biocontrol of Seedborne Fungi on Small-Grained Cereals Using Bacillus halotolerans Strain B33

The development of biological pesticides is rapidly becoming an integral aspect of pest management in sustainable agriculture. This study was conducted to evaluate the effectiveness of Bacillus halotolerans strain B33 against three common seedborne fungal pathogens-Fusarium graminearum, Alternaria alternata, and Aspergillus flavus. B33 strain identity was determined using the 16S rRNA and tuf gene sequences. Commercial wheat, barley, oat, and rye seeds were artificially infected by fungal isolates and then treated with B33 overnight culture in Nutrient Broth. The obtained results indicate high efficacy against F. graminearum (83.55-94.38%) and A. alternata (85.05-96.70%), whereby the highest efficacy was noted on wheat seed and the lowest was detected on rye seed. On the other hand, B33 achieved 100% efficacy against A. flavus on barley, rye, and oat seeds, while being 96.24% effective against this pathogen on wheat. Principal component analysis indicated the highest treatment influence on A. flavus. The effect of all tested treatments on seed germination was statistically significant compared to the controls, whereby the number of germinated seeds declined as the seed infection rate increased. B. halotolerans strain B33 effectively managed seedborne fungal pathogens, thereby enhancing seed germination.