THE INFLUENCE OF N-METHYL-N′-NITRO-N-NITROSOGUANIDINE ON AVERMECTIN SYNTHESIS ABILITY OF STREPTOMYCES AVERMITILIS UKM AS-2179 AND APPEARING AUXOTROPHIC MUTANTS

Abstract

An important way to transition to ecologically safe agrotechnologies is the abandonment of chemical means of plant protection and the transition to biological ones. The effectiveness of the use of chemical means of plant protection is gradually decreasing, which is connected with the emergence of resistant populations of pests and pathogens. The aim of the presented work was to study the influence of N-methyl-N-nitro-N-nitrosoguanidine on the survival and isolation of highly active variants of S. avermitilis UKM As-2179, the avermectin-synthesizing activity of which would be higher than that of the original strain. Biochemical methods of determining avermectin-synthesizing activity were used in the work, the qualitative assessment of the culture's ability to synthesize avermectins was performed by the TLC method, and the concentration of avermectins in ethanol extracts was determined by the colorimetric method. The influence of N-methyl-N-nitro-N-nitrosoguanidine on the viability and antibiotic activity of the avermectin complex producer S. avermitilis UKM As-2179 was studied. It was found that the optimal time for obtaining clones with increased antibiotic activity is 15 minutes of treatment with N-methyl-N-nitro-N-nitrosoguanidine, during which 30% of the spores of the studied strain survive, and the biosynthetic activity increases by 2.7 times. To identify clones of S. avermitilis UKM As-2179 with increased synthesis of natural avermectins, the method of induced МННГ mutagenesis can be used.