Strains A. baldaniorum Sp245 and A. brasilense Sp7 formed mono- and multilayer biofilms on the surface of wheat roots both under sterile hydroponic conditions and in non-sterile soil. Derivatives of these strains carrying a plasmid with the gene of the fluorescent protein GFP were used to visualize bacterial biofilms in situ. Azospirillum biofilms/their matrix components bound to soil particles, forming aggregates in the soil, which affected not only its structure, but also the adhesion of the soil to plant roots. Under short-term drought conditions, bacteria in biofilms formed on the surface of the root epidermis and root hairs produced GFP in the root system of plants inoculated with Azospirillum. Sowings from the roots of these plants showed that GFP colonies are Azospirillum. Inoculation with strains Sp7 and Sp245 positively affected the relative water content in the leaves of plants exposed to conditions simulating short-term drought in the soil.
A. A. Shirokov (Wed,) studied this question.