Objective. Study the biological properties of the diazotroph Azospirillum brasilense 10/1, promising for improving the nitrogen nutrition of spring triticale and obtaining a high quality crop. Methods. A strain of nitrogen-fixing bacteria A. brasilense 10/1 isolated from washed roots of spring triticale Oberih Kharkivskyi by accumulation cultures method using Dobreiner semi-liquid nitrogen-free medium. Nitrogen-fixing microorganisms were isolated on potato agar with succinic acid by the Dryhalsky method. Potential nitrogenase activity on washed roots of spring triticale plants and nitrogen-fixing activity of azospirilla in pure culture were measured by gas chromatography. Electron microscopic studies of bacterial cells were performed by the method of negative contrast with uranyl acetate. Identification of azospirilla was carried out on the basis of the study of morphological, cultural, physiological and biochemical characteristics and using molecular genetic methods (16S rRNA sequence analysis). The nucleotide sequences were compared with the corresponding sequences from the international database GenBank NCBI using BLAST software. The sensitivity of bacteria to antibiotics and cereal seed pesticides was tested by disk diffusion method. Results. The active strain of nitrogen-fixing bacteria, identified as Azospirillum brasilense 10/1, was obtained by analytical selection methods. The identity of the sequences of 16S rRNA of A. brasilense 10/1 with reference strains of A. brasilense in the GenBank NCBI database is 99.5 % to 99.6 %. Diazotroph A. brasilense 10/1 is sensitive to cefotaxime, norfloxacin, chloramphenicol, gentamicin, erythromycin, kanamycin, furadonin, resistant to polymyxin, ampicillin, oxacillin, amoxicillin, ciprofloxacin, ceftriaxone. Vitavax 200FF and Fundazole dressers do not affect the development of A. brasilense 10/1, Maxim Star 025 FS somewhat inhibits the development of bacteria. Conclusion. The active strain of nitrogen-fixing bacteria A. brasilense 10/1 isolated from washed roots of triticale by methods of analytical selection, is a promising inoculant to increase yields and improve grain quality of this crop. A. brasilense 10/1 is deposited in the Depository of the Institute of Microbiology and Virology of the National Academy of Sciences of Ukraine under number B- 7317 and is protected by the patent of Ukraine No. 104212.
BIOLOGICAL PROPERTIES OF DIAZOTROPH AZOSPIRILLUM BRASILENSE ISOLATED FROM SPRING TRITICALE ROOTS
