Journal of Microbiology

Journal Article

Characterization of Nitrogen-Fixing Bacteria Isolated from Field-Grown Barley, Oat, and Wheat: Anastasia Venieraki , Maria Dimou , Eleni Vezyri , Io Kefalogianni , Nikolaos Argyris , Georgia Liara , Panagiotis Pergalis , Iordanis Chatzipavlidis , Panagiotis Katinakis; J. Microbiol. 2011;49(4):525-534. Published online September 2, 2011; DOI: https://doi.org/10.1007/s12275-011-0457-y

Abstract: Diazotrophic bacteria were isolated from the rhizosphere of field-grown Triticum aestivum, Hordeum vulgare, and Avena sativa grown in various regions of Greece. One isolate, with the highest nitrogen-fixation ability from each of the eleven rhizospheres, was selected for further characterisation. Diazotrophic strains were assessed for plant-growth-promoting traits such as indoleacetic acid production and phosphate solubilisation. The phylogenies of 16S rRNA gene of the selected isolates were compared with those based on dnaK and nifH genes. The constructed trees indicated that the isolates were members of the species Azospirillum brasilense, Azospirillum zeae, and Pseudomonas stutzeri. Furthermore, the ipdC gene was detected in all A. brasilence and one A. zeae isolates. The work presented here provides the first molecular genetic evidence for the presence of culturable nitrogen-fixing P. stutzeri and A. zeae associated with field-grown A. sativa and H. vulgare in Greece.

Research Support, Non-U.S. Gov't

Characterization of Plant-Growth Promoting Diazotrophic Bacteria Isolated from Field Grown Chinese Cabbage under Different Fertilization Conditions: Woo-Jong Yim , Selvaraj Poonguzhali , Munusamy Madhaiyan , Pitchai Palaniappan , M. A. Siddikee , Tongmin Sa; J. Microbiol. 2009;47(2):147-155. Published online May 2, 2009; DOI: https://doi.org/10.1007/s12275-008-0201-4

Abstract: Diazotrophic bacteria isolated from the rhizosphere of Chinese cabbage were assessed for other plant growth promoting characteristics viz., production of IAA, ethylene, ACC deaminase, phosphate solubilization, and gnotobiotic root elongation. Their effect on inoculation to Chinese cabbage was also observed under growth chamber conditions. A total of 19 strains that showed higher nitrogenase activity identified by 16S rRNA gene sequence analysis were found to be the members of the genera Pseudomonas and Agrobacterium belonging to α- and γ-Proteobacteria groups. These strains were also efficient in producing IAA and ACC deaminase though they produced low levels of ethylene and no phosphate solubilization. In addition, inoculation of selected diazotrophic bacterial strains significantly increased seedling length, dry weight, and total nitrogen when compared to uninoculated control. The colonization of crop plants by diazotrophic bacteria can be affected by many biotic and abiotic factors, and further studies are oriented towards investigating the factors that could influence the establishment of a selected bacterial community.

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