Cell extracts of an Escherichia coli strain that overproduces the regulatory protein FIXJ from Rhizobium meliloti promoted transcription of fixK, a known FIXJ-dependent gene, in a coupled transcription-translation assay. Activation by FIXJ was dependent on the sigma 70 holoenzyme form of RNA polymerase.

Early nodulin 2 (ENOD2) transcripts and protein are specifically found in the inner cortex of legume nodules, a location that coincides with the site of a barrier to O2 diffusion. The extracellular glycoprotein that binds the monoclonal antibody MAC236 has also been localized to this site. Thus, it has been proposed that these proteins function in the regulation of nodule permeability to O2 dif...

Spontaneous mutants of Rhizobium meliloti L5-30 defective in motility or chemotaxis were isolated and compared against the parent with respect to symbiotic competence. Each of the mutants was able to generate normal nodules on the host plant alfalfa (Medicago sativa), but had slightly delayed nodule formation, diminished nodulation in the initially susceptible region of the host root, and relat...

in order to study the effects of growth promoting bacteria (gpr) and mycorrhizal fungi on seedling emergence, establishment and growth of two ecotypes alfalfa under salinity stress condition, an experiment was conducted in greenhouse of college of agriculture and natural resources, university of tehran in summer 2011. the experiment was arranged as a factorial with three replications. experimen...

As a means of investigating gene function, we developed a robust transcription fusion reporter vector to measure gene expression in bacteria. The vector, pTH1522, was used to construct a random insert library for the Sinorhizobium meliloti genome. pTH1522 replicates in Escherichia coli and can be transferred to, but cannot replicate in, S. meliloti. Homologous recombination of the DNA fragments...

Legumes develop different types of lateral organs from their primary root, lateral roots and nodules, the latter depending on a symbiotic interaction with Sinorhizobium meliloti. Phytohormones have been shown to function in the control of these organogeneses. However, related signaling pathways have not been identified in legumes. We cloned and characterized the expression of Medicago truncatul...

Rhizobia are symbiotic soil bacteria able to intracellularly colonize legume nodule cells and form nitrogen-fixing symbiosomes therein. How the plant cell cytoskeleton reorganizes in response to rhizobium colonization has remained poorly understood especially because of the lack of an in vitro infection assay. Here, we report on the use of the heterologous HeLa cell model to experimentally tack...

Post-transcriptional regulation by trans-encoded sRNAs, for example via base-pairing with target mRNAs, is a common feature in bacteria and influences various cell processes, e.g., response to stress factors. Several studies based on computational and RNA-seq approaches identified approximately 180 trans-encoded sRNAs in Sinorhizobium meliloti. The initial point of this report is a set of 52 tr...

Sinorhizobium meliloti, a legume symbiont, and Brucella abortus, a phylogenetically related mammalian pathogen, both require the bacterial-encoded BacA protein to establish chronic intracellular infections in their respective hosts. We found that the bacterial BacA proteins share sequence similarity with a family of eukaryotic peroxisomal-membrane proteins, including the human adrenoleukodystro...

We determined the sequences for a 260-base segment amplified by the polymerase chain reaction (corresponding to positions 44 to 337 in the Escherichia coli 16s rRNA sequence) from seven strains of fast-growing soybean-nodulating rhizobia (including the type strains of Rhizobium fredii chemovar fredii, Rhizobium fredii chemovar siensis, Sinorhizobium fredii, and Sinorhizobium xinjiangensis) and ...