Marine dinitrogen (N2) fixation studies have focused nearly exclusively on cyanobacterial diazotrophs; however γ-proteobacteria are an abundant component of the marine community and have been largely overlooked until recently. Here we present a phylogenetic analysis of all nifH γ-proteobacterial sequences available in public databases and qPCR data of a γ-proteobacterial phylotype, Gamma A (UMB...

We expressed the Arabidopsis thaliana gene for phytochelatin synthase (PCS(At)) in Mesorhizobium huakuii subsp. rengei B3, a microsymbiont of Astragalus sinicus, a legume used as manure. The PCS(At) gene was expressed under the control of the nifH promoter, which regulates the nodule-specific expression of the nifH gene. The expression of the PCS(At) gene was demonstrated in free-living cells u...

Marine diazotrophs fix dinitrogen gas into bioavailable nitrogen that drives the ocean cycle; yet, efforts to infer global diazotroph distributions have been limited by a sparsity of observations. In situ measurements nifH gene abundance (essential for fixation) are increasingly being used inform biogeography diazotrophs. However, comparing such abundances spatially, temporally and between spec...

Identification and selection of nitrogen-fixing bacterial strains for inoculation into native leguminous tree species can assist in the recovery degraded areas. Additionally, from these areas are genetic resources adapted to conditions thus suitable selection. The aim this study was symbiotically genetically characterize 18 Rhizobium Bradyrhizobium genera isolated Machaerium nyctitans, Platypod...

In the presence of ammonium ion, Nodularia spumigena strain AV1, a filamentous, heterocystous cyanobacterium isolated from the Baltic Sea, lost aerobic nitrogen-fixation activity while maintaining heterocyst frequency along the filaments. Real-time RT-PCR showed that the expression of nifH (encoding the dinitrogenase reductase component of the nitrogenase enzyme) was suppressed and the levels o...

Oligotrophic oceanic waters of the central ocean gyres typically have extremely low dissolved fixed inorganic nitrogen concentrations, but few nitrogen-fixing microorganisms from the oceanic environment have been cultivated. Nitrogenase gene (nifH) sequences amplified directly from oceanic waters showed that the open ocean contains more diverse diazotrophic microbial populations and more divers...

Abstract Engineering nitrogen fixation in eukaryotes requires high expression of functional nitrogenase structural proteins, a goal that has not yet been achieved. Here we build knowledge-based library containing 32 nifH sequences from prokaryotes diverse ecological niches and metabolic features combine with rapid screening tobacco to identify superior NifH variants for plant mitochondria expre...