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Genetic analysis of an fnr-like gene of Herbaspirillum seropedicae
Raeder, K.R.1; Souza, E.M.1; Monteiro. R.A .1; Wassen, R.2; Pedrosa, F.O.1; and Steffens, M.B.R1.
1Depto de Bioquímica, Universidade Federal do Paraná; 2Depto de Genética, Universidade Federal do Paraná
FNR is a global transcriptional regulator that controls synthesis of genes whose functions facilitate growth under O2-limiting conditions. Anaerobically purified FNR protein, the product of the fnr gene, contains a [4Fe-4S]2+ cluster that functions as an O2 sensor. In Klebsiella pneumoniae, FNR is required to relieve NifL inhibition of NifA under anaerobic conditions. We have investigated the fnr genes of H. seropedicae. Plasmids containing fnr-like genes from H. seropedicae were identified in the database of the H. seropedicae Genome Project, GENOPAR. Three plasmids containing different fnr-like genes were isolated and called fnr1, fnr2 and fnr3. The fnr1 gene was inactivated by an insertion mutation and the obtained mutants were deficient (< 90%) in nitrogen fixation, but had wild type growth rates in the presence of NO3- and NH4+. These results support previous suggestions of the involvement of the FNR protein in nitrogen fixation in H. seropedicae. Supported by MCT / PRONEX, CNPq, SETI / Fundação Araucária.
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