Molecular-genetic and biotechnological foundations for the development of complex microbial preparations for balanced plant nutrition

Abstract

The purpose of this study was to identify the molecular genetic mechanisms that regulate the functional activity of microbial preparations in the plant rhizosphere. The methodology included analysing the expression of key genes, comparing the effectiveness of different strains of microorganisms in the soil environment, summarising the factors affecting the stability of biological products, and systematising the data to establish the relationship between genetic mechanisms and agronomic indicators. The results confirmed that the expression of key genes responsible for nitrogen fixation, phosphorus mobilisation, and synthesis of biologically active compounds determines the effectiveness of biological products in the soil environment, which was verified by genetic analysis of functional markers, microbiological study of strain viability, and analytical determination of available nutrients and plant productivity. The combination of nitrogen-fixing, phosphate-mobilising, and biostimulating microorganisms ensured the development of stable microbial communities capable of increasing the bioavailability of nutrients and crop productivity. When Azospirillum brasilense was used on non-legume crops, the concentration of ammonium compounds in the rhizosphere increased by up to 40%, which was accompanied by an increase in nitrogen nutrition. The use of phosphate-mobilising bacteria allowed reducing the rate of phosphate fertiliser application by 25-40% without loss of yield. Overall, the use of biological products on cereals, legumes, and vegetables reduced the need for chemical fertilisers by 20-30% without reducing agronomic efficiency. Stabilisation of microorganisms through microencapsulation ensured increased survival in the soil environment and uniform distribution in the rhizosphere, while spray drying enabled the production of powdered forms of biological products with a long shelf life. The combination of microbial preparations with nanoforms of mineral fertilisers contributed to the uniform release of nutrients, which positively influenced their assimilation, although the exact coefficients of this process were not presented in the study. The practical significance of the findings obtained lies in the possibility of targeted development of biological products with the predicted ability to increase the uptake of nitrogen and phosphorus by plants, reduce the need for mineral fertilisers, and ensure stable crop productivity under intensive farming conditions.