Diazotrophic Burkholderia Species Associated with Field-Grown Maize and Sugarcane

• Published in: Applied and Environmental Microbiology Vol. 72; no. 5; pp. 3103 - 3110
• Main Authors: Perin, L, Martínez-Aguilar, L, Castro-González, R, Estrada-de los Santos, P, Cabellos-Avelar, T, Guedes, H.V, Reis, V.M, Caballero-Mellado, J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01.05.2006
• Subjects: Agriculture; amplified ribosomal DNA restriction analysis; Bacteria; Biological and medical sciences; Brazil; Burkholderia; Burkholderia - classification; Burkholderia - growth & development; Burkholderia - isolation & purification; Burkholderia - metabolism; Burkholderia tropica; Burkholderia unamae; Burkholderia xenovorans; Corn; Crops, Agricultural - growth & development; Crops, Agricultural - microbiology; Enzymes; Fundamental and applied biological sciences. Psychology; genes; Genes, rRNA; Mexico; Microbiology; Molecular Sequence Data; nifH gene; Nitrogen Fixation; nitrogen-fixing bacteria; nucleotide sequences; Oxidoreductases - genetics; Pathology; Plant Microbiology; Polymerase Chain Reaction; Restriction Mapping; rhizoplane; rhizosphere; Ribonucleic acid; ribosomal DNA; ribosomal RNA; RNA; RNA, Ribosomal, 16S - genetics; Saccharum; Saccharum - growth & development; Saccharum - microbiology; Sequence Analysis, DNA; soil bacteria; Species Specificity; Sugarcane; Zea mays; Zea mays - growth & development; Zea mays - microbiology; Brazil; Mexico; Saccharum; Monocotyledones; Zea mays; Gramineae; Angiospermae; Nitrogen fixation; Bacteria; Spermatophyta; Sugar cane; Burkholderia; Diazotrophy
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/AEM.72.5.3103-3110.2006

Until recently, diazotrophy was known in only one of the 30 formally described species of BURKHOLDERIA: Novel N₂-fixing plant-associated Burkholderia species such as B. unamae, B. tropica, and B. xenovorans have been described, but their environmental distribution is scarcely known. In the present study, the occurrence of N₂-fixing Burkholderia species associated with different varieties of sugarcane and maize growing in regions of Mexico and Brazil was analyzed. Only 111 out of more than 900 isolates recovered had N₂-fixing ability as demonstrated by the acetylene reduction assay. All 111 isolates also yielded a PCR product with primers targeting the nifH gene, which encodes a key enzyme in the process of nitrogen fixation. These 111 isolates were confirmed as belonging to the genus Burkholderia by using a new 16S rRNA-specific primer pair for diazotrophic species (except B. vietnamiensis) and closely related nondiazotrophic BURKHOLDERIA: In Mexico, many isolates of B. unamae (predominantly associated with sugarcane) and B. tropica (more often associated with maize) were recovered. However, in Brazil B. tropica was not identified among the isolates analyzed, and only a few B. unamae isolates were recovered from one sugarcane variety. Most Brazilian diazotrophic Burkholderia isolates (associated with both sugarcane and maize plants) belonged to a novel species, as revealed by amplified 16S rRNA gene restriction profiles, 16S rRNA gene sequencing, and protein electrophoresis. In addition, transmissibility factors such as the cblA and esmR genes, identified among clinical and environmental isolates of opportunistic pathogens of B. cenocepacia and other species of the B. cepacia complex, were not detected in any of the plant-associated diazotrophic Burkholderia isolates analyzed.