Antagonistic activity of microorganisms isolated from chernozem against plant pathogens

Abstract

The aim of the work was to establish the antagonistic activity spectrum of microorganisms of different taxonomic groups isolated from Calcic Chernozem, against plant pathogens. Antagonistic activity of the soil microorganisms against phytopathogens was checked by diffusion in agar, taking into account the diameter of the growth inhibition zones around the blocks. The strains of phytopathogenic bacteria Xanthomon ascampestris 8003b, Pectobacterium carotovorum 8982, Pseudomonas syringae pv. atrofaciens 8254, Pseudomonas syringae pv. lachrymans 7595 and fungi Fusarium oxysporum 54201, Fusarium culmorum 50716, Cladosporium herbarum 16878, Alternaria alternata 16 and Aspergillus niger 25 were used as the test cultures. Soil isolates were screened to determine the spectrum and level of their antagonistic activity in relation to test cultures of phytopathogens. The most active micromycetes isolates were Trichoderma lignorum 14, which exhibited antagonism against four of the five fungal species and three of the four bacteria, and Trichoderma longibrachiatum 17, active against all the tested plant pathogens. Among the actinobacteria, the most active isolates belonged to the genus Streptomyces: Streptomyces sp. 31 inhibited the growth of all tested plant pathogens, and Streptomyces sp. 35 showed antagonism against all phytopathogenic fungi and three of the four bacterial species. The most active bacterial isolates identified as Bacillus megaterium 3 and Bacillus brevis 6 inhibited the growth of all phytopathogenic cultures tested. All active antagonist isolates had no phytotoxic effect on spring barley seedlings, on the contrary, T. longibrachiatum 17 significantly increased the number of germinated seeds, and Streptomyces sp. 35 had a positive effect on shoot growth. Selected soil cultures can be used for the creation of plant protection products against fungal and bacterial disease.