Aboveground plant performance is strongly influenced by belowground microorganisms, some of which are pathogenic and have negative effects, while others, such as nitrogen-fixing bacteria and arbuscular mycorrhizal fungi, usually have positive effects. Recent research revealed that belowground interactions between plants and functionally distinct groups of microorganisms cascade up to abovegroun...

The study of free-living nitrogen-fixing organisms in bulk soil is hampered by the great diversity of soil microbial communities and the difficulty of relating nitrogen fixation activities to individual members of the diazotroph populations. We developed a molecular method that allows analysis of nifH mRNA expression in soil in parallel with determinations of nitrogen-fixing activity and bacter...

Azotobacter vinelandii requires a high complement of iron and an efficient iron acquisition system to support nitrogen fixation. To circumvent problems inherent in batch culture trace metal studies, continuous cultures were used to measure the response of A. vinelandii to iron stress. Iron was found to be growth limiting for nitrogen-fixing A. vinelandii at a concentration as high as 12.5 muM; ...

It has been reported (Gunter, 1954) that Mg++ prolongs the viability of various microorganisms suspended in potassium phosphate buffer, and that celLs of Azotobacter are singularly affected by MgSO4. It was previously observed (Goucher and Kocholaty, 1954) that MgSO4 is required for the oxidation of several organic compounds by whole cells of Azotobacter agile. Data presented in this communicat...

Ginger is used as one of the important ingredients in traditional well modern medicine besides a spice. It boosts immunity and rich source many biologically active substances minerals. Although it medicinally crop, its productivity is, however, affected due to poor nutrient management therefore requires an adequate supply nutrients form inorganic fertilizers or organic manuring, mixture both. I...

Rnf proteins are proposed to form membrane-protein complexes involved in the reduction of target proteins such as the transcriptional regulator SoxR or the dinitrogenase reductase component of nitrogenase. In this work, we investigate the role of rnf genes in the nitrogen-fixing bacterium Azotobacter vinelandii. We show that A. vinelandii has two clusters of rnf-like genes: rnf1, whose expressi...

The Azotobacter vinelandii sigma(54)-dependent transcriptional activator protein NifA is regulated by the NifL protein in response to redox, carbon, and nitrogen status. Under conditions inappropriate for nitrogen fixation, NifL inhibits transcription activation by NifA through the formation of the NifL-NifA protein complex. NifL inhibits the ATPase activity of the central AAA+ domain of NifA r...

this study was performed for evaluation of the qualitative traits of safflower (carthamus tinctorius l.) as affected by azotobacter and mycorrhizal symbiosis (host plant root symbiosis with the glomus fungi) as factorial experiment based on randomized complete block design with three replications in research farm of college of arak islamic azad university during growing season of 2011-2012. tre...