Preliminary Results of Biological Control of Pectobacterium spp. in Potato Using an Antagonistic Bacillus Strain
Abstract:
Pectobacterium spp. are responsible for soft rot and black leg in potatoes, causing substantial economic losses worldwide due the major losses post-harvest and during storage. This study aimed to isolate and characterize the pathogen from local infected potato tubers and evaluate the antagonistic potential of local bacterial isolates. Eighty actinobacteria and twenty Bacillus strains were tested in vitro against Pectobacterium where one Bacillus strain demonstrated strong antagonistic activity as whole culture. Secondary metabolite extractions using organic solvents indicated that ethyl acetate extracts were the most effective, followed by cyclohexane and acetone frac tions, suggesting the production of both semi-polar and hydrophobic antimicrobial compounds. Hydroponic de tached leaf assays and in planta assays achieved complete disease suppression (0% incidence vs 100% in pathogen controls). Fisher's exact test confirmed highly significant differences (p ≤ 0.0143 for all comparisons). No symp toms or phytotoxicity occurred in Bacillus treatments, demonstrating biocontrol potential of this native Bacillus isolate for sustainable Pectobacterium soft rot management in potato, with possible PGPR activity.
