Incidence of microorganisms antagonistic to plant pathogenic fungi Bipolaris sorokiniana and Fusarium sp. in different soil communities

Abstract

The antibiotic activity of conidia germination of the fungi Bipolaris sorokiniana and Fusarium sp. in the culture filtrate of the antagonistic microorganisms identified in different soil communities have been quantitatively assessed. According to the research results, among 54 tested soil bacteria isolates, 26 have manifested a verified antagonistic activity to Bipolaris sorokiniana, 27 – to Fusarium sp. (TIG6), 36 – to Fusarium sp. (Y7ec), 40 – to Fusarium sp. (T2ec), as proven by the results of the mathematical treatment of the collected data (statistical significance p<0.01). It should be noted that the greatest number of the antagonists to plant pathogenic fungi Bipolaris sorokiniana were found in the soil collected from underneath the wheat of the Tulunskaya-12 breed. The maximum number of the organisms antagonistic to fungi Fusarium sp. were found in the soil taken from underneath indoor plants and sod-meadow soil. Preliminary identification of the antagonistic soil bacteria has shown that the majority of the antagonistic bacteria represent the coryneform bacteria, including Arthrobacter sp. and Micobacterium sp., Bacillus sp. and Pseudomonas sp., Actinobacteria group. A cluster and factor analysis of the test cultures by their sensitivity to the culture filtrate of the soil bacteria showed that the greatest similarity in the reaction to the bacterial metabolites is demonstrated by the isolates of Fusarium sp. T2ec and Y7ec. Compared to all isolates of Fusarium sp., Bipolaris sorokiniana show a significantly different reaction to the metabolites produced by soil bacteria. The x2 criterion-based statistic analysis did not show any difference in the incidence of the antagonistic microorganisms in the used test cultures.