The nifA gene expression is enhanced in the fnr mutant strains from H. seropedicae.
(A) Schematic representation of native and mutant nifA::lacZ fusions assayed for β-Galactosidase activity in fnr mutant strains is showed. Full crosses indicate deletions, while dotted crosses indicate point mutations. The β-Galactosidase activity of different nifA::lacZ transcriptional fusions in H. seropedicae SmR1 and fnr mutant strains were assayed under 5 mM (B) or 20 mM of NH4Cl (C). The colour code used for each transcriptional fusion in the bar graphs in B and C is represented in A. Results showed are representative of two independent experiments.