In the thesis work the system approach to the study of a complex metabolites of soil strepomycetes-antagonists was theoretically substantiated and experimentally demonstrated. It was determined the biological (phytoprotective, growth-stimulating, adaptogenic) activity of bioformulations in bioregulation of plants at the molecular, cellular, and organism levels. This gives backgrounds for the creation of fundamentally new multicomponent biological products for the ecologically oriented phytosanitary optimization of agrocenoses.
As a result of extensive screening among the collectible and new isolates soil streptomycetes, two strains, acting against phytopathogenic microorganisms and phytonematodes, were selected. Based on morphological, cultural, physiological and biochemical characteristics and analysis of 16S rRNA genes, they were identified as Streptomyces netropsis (Finlay et al., 1951), IMV Ac-5025 and S. violaceus (Doria 1891, Waksman 1953, Lanoot et al., 2002) IMV Aс-5027.
In the antibiotic complex of S. netropsis IMV Ac-5025 two antifungal compounds of polyene nature has been isolated and identified. One of which is the heptayen antibiotic AC1O5FWR (сandіdіn) and the second is a new unknown tetraene antibiotic.
In the antibiotic complex of S. violaceus IMV Ac-5027 two compounds has been isolated and identified as anthracycline antibiotics by rhodilunantsin A and rhodilunantsin B. The antynematode activity of its compounds was shown for the first time.
It was established that S. netropsis IMV Ac-5025 and S. violaceus IMV Ac-5027 synthesize a complex of biologically active substances among which 17 free amino acids (up to 2898 μg/g of ADB), lipids (up to 220 mg/g of ADB) including free fatty acids, phospholipids (over 18%), mono- and diglycerides, triglycerides (over 50%), sterols, sterol esters, waxes, chitinase and chitosanase enzymes were determined. An important role of the found biologically active substances on bioregulation of plants and on the establishment of plant–microbe and microbe-microbe interactions was shown.
The strain-producers are able to synthesize phytohormone-stimulants, such as auxins (up to 114 µg/g of ADB), cytokinins (up to 106 µg/g of ADB), gibberellins (up to 13 µg/g of ADA), and insignificant amounts of antystress hormone − abscisic acid. The revealed phytohormonal compounds promote plant growth and development and provide their induced systemic resistance against pathogens.
For the first time, on the basis of the identified products of sterologenesis, the possible ways of synthesis of sterol compounds (cholesterol, ergosterol, sitosterol, stigmasterol, 24-epibrassinolide from squalene precursor) by S. netropsis IMV Ac-5025, S. violaceus IMV Ac-5027 and S. avermitilis IMV Ac-5015 were described. S. avermitilis IMV Ac-5015 did not synthesize sitosterol and stigmasterol, the lack of which inhibits the reproduction of phytoparasitic nematodes.
The strategy of creation of new multicomponent polyfunctional bioformulations with phytoprotective, growth-stimulating and adaptogenic properties in one biotechnological process have been developed. On the basis of the complex of streptomycetes metabolites, the Phytovit (the strain-producer is S. netropsis IMV Ac-5025), Violar (the strain-producer is S. violaceus IMV Аc-5027) and Avercom nova (the strain-producer is S. avermitilis IMV Аc-5015 with chitosan) bioformulations were developed.
The ways of bioregulation by bioformulations of phenylpropanoid, sterolsynthesis, silencing activity were determined at the molecular and cellular levels, that to increased plant resistance to biotic and abiotic stresses (priming effect).
The quantity of microorganisms involved in the transformation of nitrogen, phosphorus and carbon compounds increased (on average by 1.5-3.3 times) in the rhizosphere of plants treated with bioformulations. The development of microbiota promote the formation of productive plant-microbe systems and suppression of soil-borne plant pathogens.
At the organism level of plant, the bioregulatory effect of metabolic bioformulations is the ability to change the hormonal balance, to stimulate the growth and development of plants that reduceses of plant damage, increases their productivity, and improves the quality of crop production. The use of bioformulations helps to increase the yield of cereals (spring wheat − up to 17-33%), vegetables (tomatoes − up to 20-66%, Chinese cabbage − by 1,5 - 2,2 times) and technical (spring rape − by 2,5 - 3 times) crops.
The usage of Phytovit, Violar, Avercom nova in the cultivation technology of cereals, vegetables and technical crops is economically effective and environmentally friendly. In the technology of growing wheat the cost-efficiency of the using of bioformulations is 7.2 to 8.6 UAH for 1 spent UAH.
