Abstract
The pathway of electron transport to nitrogenase in the endophytic β-Proteobacterium Herbaspirillum seropedicae has not been characterized. We have generated mutants in two nif-associated genes encoding putative ferredoxins, fdxA and fdxN. The fdxA gene is part of the operon nifHDKENXorf1orf2fdxAnifQmodABC
and is transcribed from the nifH promoter, as revealed by lacZ gene fusion. The fdxN gene is probably cotranscribed with the nifB gene. Mutational analysis suggests that the FdxA protein is essential for maximum nitrogenase activity, since the nitrogenase activity of the fdxA mutant strain was reduced to about 30% of that
of the wild-type strain. In addition, the fdxA mutation had no effect on the nitrogenase switch-off in response to ammonium. Nitrogenase activity of a mutant strain lacking the fdxN gene was completely abolished. This phenotype was reverted by complementation with fdxN expressed under lacZ promoter control. The results suggest that the products of both the fdxA and fdxN genes are probably involved in electron transfer during nitrogen fixation.
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- Novel species of Frankia, Frankia gtarii sp. nov. and Frankia tisai sp. nov., isolated from a root nodule of Alnus glutinosa
Imen Nouioui, Faten Ghodhbane-Gtari, Gabriele Pötter, Hans-Peter Klenk, Michael Goodfellow
Systematic and Applied Microbiology.2023; 46(1): 126377. CrossRef - Biosynthesis of Nitrogenase Cofactors
Stefan Burén, Emilio Jiménez-Vicente, Carlos Echavarri-Erasun, Luis M. Rubio
Chemical Reviews.2020; 120(12): 4921. CrossRef - Modulation of defence and iron homeostasis genes in rice roots by the diazotrophic endophyte Herbaspirillum seropedicae
Liziane Cristina Campos Brusamarello-Santos, Dayane Alberton, Glaucio Valdameri, Doumit Camilios-Neto, Rafael Covre, Katia de Paiva Lopes, Michelle Zibetti Tadra-Sfeir, Helisson Faoro, Rose Adele Monteiro, Adriano Barbosa-Silva, William John Broughton, Fa
Scientific Reports.2019;[Epub] CrossRef - Genomic Insights Into Plant-Growth-Promoting Potentialities of the Genus Frankia
Imen Nouioui, Carlos Cortés-albayay, Lorena Carro, Jean Franco Castro, Maher Gtari, Faten Ghodhbane-Gtari, Hans-Peter Klenk, Louis S. Tisa, Vartul Sangal, Michael Goodfellow
Frontiers in Microbiology.2019;[Epub] CrossRef - Electron Transfer to Nitrogenase in Different Genomic and Metabolic Backgrounds
Saroj Poudel, Daniel R. Colman, Kathryn R. Fixen, Rhesa N. Ledbetter, Yanning Zheng, Natasha Pence, Lance C. Seefeldt, John W. Peters, Caroline S. Harwood, Eric S. Boyd, William W. Metcalf
Journal of Bacteriology.2018;[Epub] CrossRef - Nitrogen fixation control in Herbaspirillum seropedicae
Leda Satie Chubatsu, Rose Adele Monteiro, Emanuel Maltempi de Souza, Marco Aurelio Schuler de Oliveira, Marshall Geoffrey Yates, Roseli Wassem, Ana Claudia Bonatto, Luciano Fernandes Huergo, Maria Berenice Reynaud Steffens, Liu Un Rigo, Fabio de Oliveira
Plant and Soil.2012; 356(1-2): 197. CrossRef - Organization of nif gene cluster in Frankia sp. EuIK1 strain, a symbiont of Elaeagnus umbellata
Chang Jae Oh, Ho Bang Kim, Jitae Kim, Won Jin Kim, Hyoungseok Lee, Chung Sun An
Archives of Microbiology.2012; 194(1): 29. CrossRef