Biocontrol of Winter Wheat Root Rot by Rhizosphere Microorganisms in Kazakhstan

Root rot remains one of the most significant diseases of winter wheat (Triticum aestivum L.) in Kazakhstan, resulting in substantial yield losses. This study aimed to isolate and identify rhizosphere microorganisms associated with winter wheat and evaluate their antagonistic activity against root rot pathogens in the Almaty region of Kazakhstan. In total, seven bacterial and fungal isolates, belonging to the genera Bacillus, Lysinibacillus, and Trichoderma, were identified. Strain K-C-24 showed 99.87% homology with Bacillus mojavensis. Trichoderma asperellum strains GL and 101 showed the highest antagonistic activity, effectively inhibiting the growth of all tested pathogens, with inhibition reaching zones up to 37 mm. Bacterial strain K-C-24 (B. mojavensis) was active against Bipolaris sorokiniana with an inhibition zone of 23.5±0.5 mm, and its culture filtrate showed a strong inhibitory effect on F. oxysporum (42±0.5 mm), but showed no activity against other pathogens. Other isolates showed no significant antagonistic activity. The greenhouse experiment demonstrated the lowest rates of damage to the roots of wheat seedlings infected by F. oxysporum when treated with a consortium of bacteria from the genera Bacillus and Lysinibacillus (Mix bac) and the strain T. asperellum GL. The obtained results confirm the potential of using local antagonist strains, especially T. asperellum, B. mojavensis, and a consortium of bacteria, Bacillus and Lysinibacillus (Mix bac) strains, for the development of environmentally safe biopreparations against root rot of winter wheat in the Almaty region of Kazakhstan.