INVESTIGATING THE FUNGICIDAL POTENTIAL OF ANEURINIBACILLUS MIGULANUS NR_112214.1 IN THE MANAGEMENT OF PHYTOPATHOGENS INFECTING CHILLI

Biological control of harmful fungal pathogens in chilli is crucial for ensuring food and environmental safety. Therefore, this study explored the fungicidal potential of various Bacillus isolates against Macrophomina phaseolina, Rhizoctonia solani, Fusarium oxysporum, and Sclerotium rolfsii, which are known to cause several diseases in chilli plants. A total of 167 bacterial treatments were screened for their antagonistic potential, comprising 161 Bacillus isolates (coded B1-B161), and 6 proven bio-control agents. From this initial screening, 25 treatments were chosen for further evaluation using dual plate assays. Among the selected isolates, Bacillus isolate B7 demonstrated significant inhibitory effects on the growth of the aforementioned phytopathogens, achieving a reduction of 60-72% in confrontation assay. Pathogenicity tests showed that the soil containing B7 had a notably lower disease incidence (18.7-27.7%) compared to untreated control (60-70%), resulting in an ~ 70% disease reduction over the control. Furthermore, B7 exhibited superior plant growth parameters, including the highest shoot length (8.2-8.8 cm), root length (7.8-9.5 cm), and dry biomass (0.85 g) when challenged with the selected phytopathogens. Additionally, it produced the highest levels of lipase (17 mm), pectinase (25 mm), alongside strong biofilm formation (++++), and hydrogen cyanide activities. B7 has been identified as Aneurinibacillus migulanus NR_112214.1. The highest antifungal activity was recorded in the intracellular crude extract (11.3-14.6 mm), and extracellular crude extract (15-20.6 mm) containing secondary metabolites of A. migulanus, both of which surpassed the activity of carbendazim (10-17mm). Furthermore, GC-MSD analysis identified 31 intracellular, and 31 extracellular secondary metabolites. Our research confirms the efficacy of A. migulanus in managing diseases in chillies caused by M. phaseolina, R. solani, F. oxysporum, and S. rolfsii.