Phytotoxicity and antioxidant activity of actinomycetes in soil ecosystems

Abstract

Abstract The phytotoxicity, antioxidant activity and optical density of the actinomycetes strains Streptomyces carpaticus RCAM04697, Nocardiopsis umidischolae RCAM04882, Nocardiopsis umidischolae RCAM04883. The strains were isolated from the soil ecosystems of the arid zone and deposited in the Departmental Collection of Useful Microorganisms for Agricultural Purposes of the Federal State Budget Scientific Institution All-Russian Research Institute of Agriculture (Pushkin). The phylogenetic position of the strains was determined based on the 16S rRNA gene sequencing. These strains have pronounced insectoacaricidal, fungicidal and antiviral properties. The phytotoxicity of the suspensions and strain extracts were investigated at two concentrations: 0.5 mg/ml и 1.0 mg/ml. A spectrophotometric study was carried out in order to identify groups of dominant substances of metabolites of the studied strains. The analysis was carried out at wavelengths from 330 to 1000 nm, with a step of 10 nm. As a result of spectrophotometric analysis of all studied samples, the indicators of optical density (A) and light transmission (T) were analyzed. It was found that all versions of suspensions and extracts of the three strains are non-toxic, and the concentration 0.5 mg/ml proved to be more effective than concentration 1 mg/ml, which exhibits inhibitory properties. Suspension (88.8 %) and aqueous-alcoholic extract (76.0 %) of S. carpaticus RCAM04697 strain showed the highest antioxidant activity. In all the studied samples, a high antioxidant activity was revealed relative to the control. Spectrophotometric analysis of the studied samples made it possible to identify substances with the appropriate wavelengths that can be attributed to polyene antibiotics.