Denitrifier Community Composition Along Nitrate Gradient In Suquia River Bed-Sediment

REYNA, LUCIANA; WUNDERLIN, DANIEL; GENTI-RAIMONDI, SUSANA

Mar del Plata, Buenos Aires, Argentina

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2007

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

To understand the composition and structure of denitrifying communities along nitrate gradient in the Suquía River, the molecular diversity of gene from sediments obtained at seven stations was examined. The gene encoding the membrane bound nitrate reductase was selected as a functional marker for the nitrate-reducing community. The composition was analyzed using RFLP of , together with cloning and sequencing. In addition, a fingerprint of the total bacterial community was assessed by RISA analysis. The results show different RFLP patterns in each community site. Two libraries of the DNA samples of the most distant sites were constructed. The clones were subjected to RFLP analysis and grouped. Nine and 20 different sequences from each library were obtained with all clones exhibiting between 62-90 % identity at the amino acid level to those of cultivated denitrifiers and other environmental clones in the database. sequences clustered into three major groups supported by phylogenetic analyses and, all sequences amplified from environmental DNA clustered in the Gram-negative group. The results indicate that some populations were indeed distinct, although further sequencing would be required to fully characterize the highly diverse denitrifying communities at all sites.