Scientific novelty and practical significance. Previously unexplained aspects of the biosynthetic capacity of S. netropsis IMV Ac-5025 have been studied. Correlations dependence in the biosynthesis of polyene antibiotics with other BAS - auxins, cytokinins, abscisic acid, sterols streptomycetes were found for the first time. The possibility of factor analysis using as a method of theoretical prediction for the selection of optimal conditions for the cultivation of producer and the accumulation of the useful metabolite due to the introduction of exogenous compounds was proved. The advantages of using an organic nutrient medium for the accumulation of polyene antibiotics, phytohormones, and sterols of the producer in biotechnology were showed. The effectiveness of the use of soil streptomycete metabolites for in vitro production of tomato regenerating plants with prolonged resistance to parasitic phytonematodes and phytopathogens has been demonstrated for the first time. The efficiency of Phytovit bioformulation in the priming effect in plants was elucidated.
S. netropsis IMV Ac-5025 accumulated the largest amount of polyene antibiotics in biomass in the stationary growth phase (on the 7th day) during the cultivation under the submerged conditions, namely: 386.5 μg/g ADB in synthetic and 2318.2 μg/g ASB in organic nutrient media. It was found that polyene antibiotics accumulate for 1 day of cultivation that indicates their structural role in the metabolism of streptomycetes for the first time. Therefore, the addition of these substances in the stationary growth phase is advisable to determine the effect of exogenous substances on the biosynthesis of polyene antibiotics and other BAS by the strain.
Factor analysis showed that the biosynthesis of polyene antibiotics by S. netropsis IMV Ac-5025 is mostly correlated with the biosynthesis of cytokinin - isopentinyladenosine, auxin - indole-3-carbinol and sterol compound - β-sitosterol. The hypothesis about the possible regulation of the biosynthesis of polyene antibiotics by streptomycete due to the introduction of exogenous BAS was formulated based on the obtained data.
These results are important for understanding the complex relationships of metabolic pathways in streptomycetes and provide an opportunity to create in one biotechnological process bioproducts with specified properties. For the protection against phytopathogens, it is advisable to increase the polyene antibiotics content, for the priming effect - to regulate the content of auxins and cytokinins, for the increase plant resistance against nematodes - to regulate the content of sterols, for the improved resistance against abiotic stress - to change the accumulation of ABA.
Preliminary studies on the range of properties and possibilities of application of metabolic biological products Phytovit (producer - S. netropsis IMV Ac-5025), developed at the Department of General and Soil Microbiology, Zabolotny Institute of Microbiology and Virology, the National Academy of Sciences of Ukraine. It induces multilevel mechanisms of adaptive capacity of plants at the molecular, cellular, and organismal levels, that allows revealing it biological potential inherent in selection methods.
The practical significance of the results. The correlations dependence between the biosynthesis of polyene antibiotics and phytohormones and sterols by S. netropsis IMV Ac-5025 were clarified and confirmed experimentally, which makes it possible to use factor analysis as a method of theoretical prediction of metabolic accumulation. The advantages of using an organic nutrient medium for the accumulation of polyene antibiotics be the producer and the possibility of biochemical regulation of the accumulation of valuable metabolites in one biotechnological process are shown. The efficiency of application of soil streptomycete metabolites for getting in vitro of regenerating plants resistant tagainsto phytoparasitic nematodes and phytopathogens with improved yield due to the priming effect with prolonged action was proved. The schemes of cultivation of crops with the use of Fytovit are offered, according to which 13% increase in yield was obtained for sunflower hybrid NK Kondi and 23.4% for corn hybrid DKS-4082 during the dry season, while costs were reduced by UAH 3,000 per 1 ha.
