Integrated technology of the surfactants and phytohormones biosynthesis by Nocardia vaccinii IMV B-7405 for their use in crop production

Introduction.The strain Nocardia vaccinii IMV B-7405, which produces phytohormones and surfactants, is a promising agent for the development of integrated technologies to obtain complex preparation to be used in crop production.Materials and methods.Cultivation of bacteria was carried out in a liquid medium with 2% refined or waste oil and 100-300 mg/l of tryptophan (the precursor of the phytohormone auxin biosynthesis) was added to the medium.The concentration of auxins was determined by the method of high-performance liquid chromatography, surfactants -by weight method.Antimicrobial activity of surfactant was analyzed by the indicator of minimum inhibitory concentration (MIC).Greenhouse experiments were carried out using tomato plants; the number of fruits and their weight were analyzed.Determination of the protective effect of surfactants against bacterial diseases of tomatoes was carried out by the method of separated leaves.Results and discussion.It was established that in the presence of tryptophan in the culture medium of N. vaccinii IMV B-7405 the concentration of auxins was one to two orders of magnitude higher than without the biosynthesis precursor.The increase in auxins synthesis correlated with tryptophan transaminase activity -the key enzyme of auxins biosynthesis.Surfactants synthesized in the presence of tryptophan were characterized by higher antimicrobial activity against phytopathogenic bacteria: MICs were 2-4 times lower compared to those established for preparations formed without a precursor.Treatment of tomato leaves with solutions of surfactants synthesized by N. vaccinii IMV B-7405 in the presence of tryptophan contributed to the protection of leaves from phytopathogens damage.The exometabolites of N. vaccinii IMV B-7405 increased the productivity of tomatoes: the total weight increased by 82-91%, and the average fruit weight by 12-18%.Conclusions.The complex preparation based on the exometabolites (the surfactants and phytohormones) of N. vaccinii IMV B-7405 can be used to control the number of phytopathogens and increased the productivity of tomatoes.