Obtaining Melanin-Synthesizing Strains of Bacillus thuringiensis and their Use for Biological Preparations

Abstract

Background: A pivotal objective in crop production and plant protection lies in developing environmentally friendly insecticidal preparations and biostimulants. Methods: We employed Bacillus thuringiensis strains with varied insecticidal spectra and engineered melanogenic mutants. Results: We demonstrated a significant increase in insecticidal activity in the isolated mutants. Meanwhile, there was no observable impact of the enhanced synthesis of water-soluble melanin on the nature and abundance of spore and crystal formation. This heightened efficacy can be attributed to the photoprotective qualities of the synthesized pigment, shielding spores and crystals against the detrimental effects of UV radiation and insolation. We demonstrated the high biological activity of water-soluble bacterial melanin through in vivo experiments involving multiple plant species. Conclusions: Our findings indicate that bacterial melanin is a potent phytostimulant. This preparation accelerates and amplifies plant growth and development processes, leading to a substantial increase in crop yield by 20–40%. The simultaneous synthesis of two biologically active substance, melanin and insecticidal toxins, ensures an elevated level of effectiveness in utilizing melaninogenic strains.

Keywords

• bacillus thuringiensis
• melanogenic strains
• bacterial melanin
• insecticidal preparations
• phytostimulator