MICROBIAL SYNTHESIS OF PHYTOHORMONES

The aim of the review was to analyze current literature data and the results of own studies on the synthesis of auxins, cytokinins, and gibberellins by plant-associated microorganisms (living in rhizosphere, endophytic, nitrogen-fixing, and phytopathogenic), and by those not involved in symbiotic interactions. Many microorganisms can generate phytohormones, and microbial synthesis of indole-3-acetic acid can be enhanced which can be used in producing it instead of extracting it from plants or by chemical synthesis. Recent progress in intensifying the synthesis of gibberellic acid in deep and solid-phase producer cultivation allows substantially reducing the prime cost of biotechnological production of that phytohormone. The ability of microorganisms to simultaneously synthesize phytohormones and other biologically active compounds with antimicrobial, nematocidal, and other various effects enables creating complex polyfunctional microbial preparations with various biological properties for use in crop production to stimulate plant growth and pest control.