SELECTION OF MICROORGANISM STRAINS TO PROTECT GRAIN PLANTS FROM FUNGI OF GENUS FUSARIUM

Abstract

Currently, due to climate change and a number of unfavorable environmental conditions, there is a tendency to decrease the global production of wheat - one of the main grain crops. It is undeniable that the increase in grain production is closely related to the effectiveness of controlling one of the most harmful diseases of grain crops - Fusarium wilt, since there are no wheat varieties in the world that are completely resistance to Fusarium wilt. The development of biotechnological approaches to obtaining new microbial preparations to protect winter wheat from Fusarium pathogens is relevant for the biological protection of winter wheat in organic farming technologies and in integrated protection systems, significantly reducing the xenobiotic pressure on agrocenoses. The purpose of the work was to isolate and screen strains of bacteria of the genera Bacillus and Pseudomonas, active against mycopathogens of the genus Fusarium, detected in seed material of winter wheat. Infection with mycopathogens of the genus Fusarium depended on the field resistance of the sort, was quite high and amounted to more than 75 % of cases. The main causative agent of Fusarium wilt was F. graminearum, but F. oxysporum and F. proliferatum were also isolated. 79 strains of Bacillus spp. and 34 strains of Pseudomonas spp. were isolated from natural sources. The best antagonists to all isolated Fusarium strains were Bacillus spp. R14, R31, S19 and Pseudomonas spp. WR5 and WR7. Methanolic extracts of secondary exometabolites of the studied strains showed 1,5-2 times higher activity against Fusarium spp. when the producers were cultivated on organic nutrient media. Minimum inhibitory concentrations of extracted metabolites of Bacillus spp. R14, S19 were determined in the range of 1 mg/ml - 4 mg/ml, Pseudomonas sp. WR5 - in the range of 2 mg/ml - 4 mg/ml.