The Mechanisms of the Growth Promotion and Protective Effects of Endophytic PGP Bacteria in Wheat Plants Under the Impact of Drought (Review)

This review is devoted to the analysis and systematization of modern data on the participation of endophytic plant growth-promoting (PGP) bacteria in the regulation of growth, development, yield formation, and stress resistance of cultivated plants, mainly spring wheat as the main bread crop. The present data on the interaction of plants with PGP bacteria under normal and drought conditions are described. Particular attention is paid to the molecular mechanisms of regulation of plant metabolism by PGP bacteria, as well as their role in reducing the negative effects of drought, achieved by modulating various processes in plants, for example, improving the supply of moisture and mineral nutrients, and activating the antioxidant and osmoprotective plant systems. A key role in the adaptation and resistance/tolerance of plants caused by PGP bacteria is played by their ability to produce various metabolites with the properties of biologically active substances, including substances with antimicrobial and hormonal activity, enzymes and other compounds. Information about the endophytic microbiome of wheat is given and the elucidation of its role and functions in the plant stress response and adaptation that are necessary for the development of effective and safe strategies for their practical application in order to maximize the adaptation and productive potential of wheat under changing environmental conditions.