Molecular characterization of nitrogen-fixing bacteria isolated from brazilian agricultural plants at São Paulo state

• Published in: Brazilian journal of microbiology Vol. 39; no. 3; pp. 414 - 422
• Main Authors: Reinhardt, Erica L, Ramos, Patrícia L, Manfio, Gilson P, Barbosa, Heloiza R, Pavan, Crodowaldo, Moreira-Filho, Carlos A
• Format: Journal Article
• Language: English
• Published: Brazil Springer Nature B.V 01.07.2008; Sociedade Brasileira de Microbiologia
• Subjects: Azospirillum; Azospirillum brasilense; Bacteria; Biochemistry; Enterobacteriaceae; Environmental Microbiology; Herbaspirillum; Manihot esculenta; MICROBIOLOGY; Molecular biology; Nitrogen; Plant pathology; Pseudomonas; Stenotrophomonas; Zea mays; diazotrophs; molecular systematics; endophytic bacteria; selective isolation; bactéria endofítica; sistemática molecular; diazotróficas; isolamento seletivo
• ISSN: 1517-8382; 1678-4405; 1678-4405
• DOI: 10.1590/S1517-83822008000300002

Fourteen strains of nitrogen-fixing bacteria were isolated from different agricultural plant species, including cassava, maize and sugarcane, using nitrogen-deprived selective isolation conditions. Ability to fix nitrogen was verified by the acetylene reduction assay. All potentially nitrogen-fixing strains tested showed positive hybridization signals with a nifH probe derived from Azospirillum brasilense. The strains were characterized by RAPD, ARDRA and 16S rDNA sequence analysis. RAPD analyses revealed 8 unique genotypes, the remaining 6 strains clustered into 3 RAPD groups, suggesting a clonal origin. ARDRA and 16S rDNA sequence analyses allowed the assignment of 13 strains to known groups of nitrogen-fixing bacteria, including organisms from the genera Azospirillum, Herbaspirillum, Pseudomonas and Enterobacteriaceae. Two strains were classified as Stenotrophomonas ssp. Molecular identification results from 16S rDNA analyses were also corroborated by morphological and biochemical data.