کنترل بیولوژیکی بلایت دیررس سیب‌زمینی با گونه‌های Bacillus

Late blight, caused by Phytophthora infestans, is the most destructive disease of potato (Solanum tuberosum) crops worldwide. Control methods largely rely on synthetic fungicides or copper-based products. In sustainable agricultural systems, managing plant diseases using biological agents is recognized as a cost-effective and environmentally friendly approach. This study was conducted to assess the biocontrol efficacy of rhizobacterial strains against early blight disease of potatoes. Antagonistic testing of 15 bacterial strains was performed in vitro against P. infestans. Based on the results, three strains of Bacillus bacteria were selected for greenhouse studies. Two potato varieties were chosen for the greenhouse studies: a disease-susceptible variety (Agria) and a disease-resistant variety (Jelly). Bacterial inoculation was carried out at the time of planting the tubers in the soil, and zoospore inoculation was conducted on the aerial parts at the 4-leaf stage of the seedlings. The results of the antagonistic tests showed that the bacterium B. atrophaeus inhibited the growth and development of mycelium by up to 85% under in vitro conditions. In greenhouse conditions, B. atrophaeus significantly reduced the infection of P. infestans in the complete potato plant of the susceptible variety. B. atrophaeus also contributed to fighting late blight disease in potato plants by inducing systemic resistance. The total phenol content, activity of defense-related enzymes (peroxidase, polyphenol oxidase, and phenylalanine ammonia-lyase), and levels of PR gene transcriptomics were increased by Bacillus. Additionally, the application of B. atrophaeus bacteria followed by pathogen inoculation challenge increased H2O2 levels by 1.9. This study highlighted the role of B. atrophaeus as an antagonist of the late blight pathogen that induces disease resistance. Incorporating this bacterium into conventional agricultural systems can reduce management costs and environmental pollution