Effects of treating wheat (Triticum aestivum) seedling roots with Azospirillum lectins to improve abiotic stress tolerance

While the effects of plant growth-promoting rhizobacterium, Azospirillum, on abiotic stress tolerance in plants are widely reported, the mechanisms that underlie this process remain elusive. Surface lectins of strains A. brasilense Sp7 and A. baldaniorum Sp245 are capable of attaching to specific carbohydrates and ensure the binding of bacteria to the surface of the plant root. They exhibit multifunctionality, and the effects induced by lectins are dose-dependent. This work investigated mechanisms by which lectins improved drought tolerance in wheat (Triticum aestivum) plants. In the roots of wheat seedlings under drought stress, lectins with varying intensities increased the activity of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT). Lectins caused a decrease in lipid peroxidation, but increased the content of secondary metabolites such as total phenolics and flavonoids. In the roots of stressed seedlings, lectins increased the total protein content and caused a dose-dependent change in the electrophoretic spectra of low molecular weight proteins. It was concluded that Azospirillum lectins, due to their ability to influence the metabolism of the host plant, are involved in adaptive changes in the roots of wheat seedlings. Lectins can regulate the relationship between bacteria and their hosts when soil and climatic factors change.