New Streptomyces Strains As Promising Biofungicides

Due to the contamination of crop production and the harmful side effects of chemical fungicides on the environment, the development of biofungicides for plant protection is relevant. Many natural isolates of the genus Streptomyces have antagonistic activity against phytopathogenic fungi and bacteria. This indicates the expediency of further searching for antagonistically active representatives among streptomycetes. In this work, the genotypic and phenotypic properties of six new strains of streptomycetes with high antagonistic activity were studied. The strains were isolated from the soils of different natural zones and the rhizosphere of different agricultural plants. Based on the data on the nucleotide sequences of the 16S rRNA gene fragment, the phylogenetic position of natural isolates was determined. Their potential for use as biofungicides is characterized: the spectra of antifungal action and phytotoxicity (phytoregulatory action). It was concluded that the strains of S. antimycoticus 8Al3, S. castelarensis A4, S. alfalfae 6-IZ-12, S. anulatus T-2-20, S. grise. olus 3-IZ-7, S. flavogriseus TK5 can be considered as promising biocontrol agents against harmful fungal infections of agricultural plants caused by fungi from the genera Fusarium, Bipolaris, and Alternaria. The necessity of targeted use of biofungicides in the introduction of cereals, legumes and cruciferous crops into the phytocenoses is justified.