SCREENING OF ANTAGONISTIC BACILLUS SPECIES AGAINST PHYTOPATHOGENIC pythium AND fusarium SPECIES

摘要

Phytopathogenic fungal cultures were isolated from infected tomato plants and identified on the basis of morphological and cultural characters as Pythium and Fusarium species. One hundred thermostable bacterial cultures were isolated from rhizospheresoil samples of healthy tomato plants, on nutrient agar and putatively identified as Bacillus species on the basis of morphological characters and sporulation ability. These isolates were tested for primary screening of antagonists against phytopathogenic Fusarium and Pythium species, by dual culture method on potato dextrose agar (PDA) plates. The isolates showing positive results were tested for their antifungal potency using seed plate and dual broth culture technique. Four potent antifungal Bacillus isolates were identified to species level on the basis of biochemical characters and 16S r-RNA sequencing as B. thuringiensis184, B. cereus 220, B. cereus 228 and B. subtilis 252. The extent of antifungal activity was higher in dual broth culture thanseed plate method. These potent antifungal Bacillus isolates were used to prepare bioformulations and found significant to protect tomato plants from fungal infections.