PGPR Bacteria - Promising Objects to Create BIOFERTILIZERS of Complex Action

The review summarizes literature data and the results of the authors own research on the agronomically useful group of soil microorganisms stimulating plant growth (plant-growth-promoting rhizobacteria - PGPR bacteria). PGPRs have great potential for plant growth promoting as they control pest and disease and have been considered important in sustainable agriculture. PGPR includes a promising group of bacteria that live on the surface and inside the roots of agricultural plants. They possess a number of positive properties such as fixation of molecular nitrogen of the atmosphere, decomposition of harmful chemical compounds, synthesis of substances of a hormonal nature, are able to transform difficult phosphorus soil compounds, and also prevent or reduce the growth of phytopathogens due to the ability to synthesize substances with bactericidal and fungicidal effects, as well as competition for ions iron, without which the growth of phytopathogens is difficult. In addition, PGPR bacteria provide plant resistance to adverse environmental factors: heavy metal pollution of the soil, soil salinization, and drought. Under stress caused by heavy metal contamination of the soil, PGPR bacteria enhance plant survival. Data are presented showing the prospects of using these microorganisms in the development of technologies of ecological farming in order to increase plant productivity, biocontrol over the development of plant diseases, reduce the chemical load on the soil, increase its fertility.