The transport of mannitol in is carried out by a broad-substrate polyol transporter SmoEFGK and is affected by the ability to transport and metabolize fructose.

The locus (sorbitol mannitol oxidation) is found on the chromosome of 's tripartite genome. Mutations at the locus reduce or abolish the ability of the bacterium to grow on several carbon sources, including sorbitol, mannitol, galactitol, d-arabitol and maltitol. The contribution of the locus to the metabolism of these compounds has not been previously investigated.

Complete Genome Sequences of Rhizobium gallicum M101 and Two Potential New Species Isolated from Soils in Central Canada.

Here, we report the genome sequences of Rhizobium gallicum M101, sp. strain C104, and sp. strain K102.

Inability to Catabolize Rhamnose by Rm1021 Affects Competition for Nodule Occupancy.

strains unable to grow on rhamnose as a sole carbon source are less competitive for nodule occupancy. To determine if the ability to use rhamnose as a sole carbon source affects competition for nodule occupancy in , Tn mutants unable to use rhamnose as a sole carbon source were isolated. mutations affecting rhamnose utilization were found in two operons syntenous to those of .

The Rhizobium-Legume Symbiosis: Co-opting Successful Stress Management.

The interaction of bacteria with plants can result in either a positive, negative, or neutral association. The rhizobium-legume interaction is a well-studied model system of a process that is considered a positive interaction. This process has evolved to require a complex signal exchange between the host and the symbiont.

FN1 produces an inhibitory substance that affects competition for nodule occupancy.

Bacteriocins are narrow-spectrum antibiotics of bacterial origin that can affect competition in resource-limited environments, such as the rhizosphere. Therefore, bacteriocins may be good candidates for manipulation to generate more competitive inocula for soybean. In this study, FN1, along with other Bradyrhizobia in our culture collection, was screened for bacteriocin-like activity.

qPCR assay targeting shows that row spacing and soybean density affects population.

The ability for a soybean plant to be efficiently nodulated when grown as a crop is dependent on the number of effective that can be found in close proximity to the developing seedling shortly after planting. In Manitoba, the growing of soybean as a crop has increased from less than 500 000 acres in 2008 to over 2.3 million acres in 2017.

Galactitol catabolism in Sinorhizobium meliloti is dependent on a chromosomally encoded sorbitol dehydrogenase and a pSymB-encoded operon necessary for tagatose catabolism.

The legume endosymbiont Sinorhizobium meliloti can utilize a broad range of carbon compounds to support its growth. The linear, six-carbon polyol galactitol is abundant in vascular plants and is metabolized in S. meliloti by the contribution of two loci SMb21372-SMb21377 and SMc01495-SMc01503 which are found on pSymB and the chromosome, respectively.

Characterization of Mutations That Affect the Nonoxidative Pentose Phosphate Pathway in Sinorhizobium meliloti.

is a Gram-negative alphaproteobacterium that can enter into a symbiotic relationship with and Previous work determined that a mutation in the gene, which encodes a putative transketolase, could prevent medium acidification associated with a mutant strain unable to metabolize galactose. Since the pentose phosphate pathway in is not well studied, strains carrying mutations in either and , which encodes a putative transaldolase, were characterized. Carbon metabolism phenotypes revealed that both mutants were impaired in growth on erythritol and ribose.

Succinoglycan Production Contributes to Acidic pH Tolerance in Sinorhizobium meliloti Rm1021.

In this work, the hypothesis that exopolysaccharide plays a role in the survival of Sinorhizobium meliloti at low pH levels is addressed. When S. meliloti was grown at pH 5.

Characterisation of a gene encoding a membrane protein that affects exopolysaccharide production and intracellular Mg2+ concentrations in Ensifer meliloti.

Exopolysaccharides play an important role in the physiology of a bacterial cell. Ensifer meliloti is capable of producing at least two types of exopolysaccharides (EPS): succinoglycan and galactoglucan. In E.

Common dyes used to determine bacterial polysaccharides on agar are affected by medium acidification.

In this work, we highlight effects of pH on bacterial phenotypes when using the bacteriological dyes Aniline blue, Congo red, and Calcofluor white to analyze polysaccharide production. A study of galactose catabolism in Sinorhizobium meliloti led to the isolation of a mutation in dgoK1, which was observed to overproduce exopolysaccharides when grown in the presence of galactose. When this mutant strain was spotted onto plates containing Aniline blue, Congo red, or Calcofluor white, the intensity of the associated staining was strikingly different from that of the wild type.

Functional characterization of a soybean growth stimulator Bradyrhizobium sp. strain SR-6 showing acylhomoserine lactone production.

A soybean nodule endophytic bacterium Bradyrhizobium sp. strain SR-6 was characterized for production of acyl homoserine lactones (AHLs) as quorum sensing molecules. Mass spectrometry analysis of AHLs revealed the presence of C6-HSL, 3OH-C6-HSL, C8-HSL, C10-HSL, 3oxoC10-HSL, 3oxo-C12-HSL and 3OH-C12-HSL which are significantly different from those reported earlier in soybean symbionts.

The Sugar Kinase That Is Necessary for the Catabolism of Rhamnose in Rhizobium leguminosarum Directly Interacts with the ABC Transporter Necessary for Rhamnose Transport.

Unlabelled: Rhamnose catabolism in Rhizobium leguminosarum was found to be necessary for the ability of the organism to compete for nodule occupancy. Characterization of the locus necessary for the catabolism of rhamnose showed that the transport of rhamnose was dependent upon a carbohydrate uptake transporter 2 (CUT2) ABC transporter encoded by rhaSTPQ and on the presence of RhaK, a protein known to have sugar kinase activity. A linker-scanning mutagenesis analysis of rhaK showed that the kinase and transport activities of RhaK could be separated genetically.

Draft Genome Sequence of the Bacteriocin-Producing Bradyrhizobium japonicum Strain FN1.

Bradyrhizobium japonicum strain FN1 was found to produce bacteriocin-like zones of clearing when tested against other strains of bradyrhizbia. The genome was sequenced, and several putative bacteriocin-producing genes, in addition to the expected genes involved in nodulation and nitrogen fixation, were identified.

Exopolysaccharide production in response to medium acidification is correlated with an increase in competition for nodule occupancy.

Sinorhizobium meliloti strains unable to utilize galactose as a sole carbon source, due to mutations in the De-Ley Doudoroff pathway (dgoK), were previously shown to be more competitive for nodule occupancy. In this work, we show that strains carrying this mutation have galactose-dependent exopolysaccharide (EPS) phenotypes that were manifested as aberrant Calcofluor staining as well as decreased mucoidy when in an expR(+) genetic background. The aberrant Calcofluor staining was correlated with changes in the pH of the growth medium.

Physiology, genetics, and biochemistry of carbon metabolism in the alphaproteobacterium Sinorhizobium meliloti.

A large proportion of genes within a genome encode proteins that play a role in metabolism. The Alphaproteobacteria are a ubiquitous group of bacteria that play a major role in a number of environments. For well over 50 years, carbon metabolism in Rhizobium has been studied at biochemical and genetic levels.

The lack of OmpF, but not OmpC, contributes to increased antibiotic resistance in Serratia marcescens.

The environmental organism Serratia marcescens is one of the primary causes of numerous nosocomial outbreaks and opportunistic infections. Multi-drug resistance is now a common feature among S. marcescens clinical isolates, complicating the efficacy of treatment.

Carbohydrate kinase (RhaK)-dependent ABC transport of rhamnose in Rhizobium leguminosarum demonstrates genetic separation of kinase and transport activities.

In Rhizobium leguminosarum the ABC transporter responsible for rhamnose transport is dependent on RhaK, a sugar kinase that is necessary for the catabolism of rhamnose. This has led to a working hypothesis that RhaK has two biochemical functions: phosphorylation of its substrate and affecting the activity of the rhamnose ABC transporter. To address this hypothesis, a linker-scanning random mutagenesis of rhaK was carried out.

Phylogenetic analysis of erythritol catabolic loci within the Rhizobiales and proteobacteria.

Background: The ability to use erythritol as a sole carbon source is not universal among the Rhizobiaceae. Based on the relatedness to the catabolic genes in Brucella it has been suggested that the eryABCD operon may have been horizontally transferred into Rhizobium. During work characterizing a locus necessary for the transport and catabolism of erythritol, adonitol and L-arabitol in Sinorhizobium meliloti, we became interested in the differences between the erythritol loci of S.

Characterization of the twin-arginine transport secretome in Sinorhizobium meliloti and evidence for host-dependent phenotypes.

The twin-arginine transport (Tat) system is essential for cell viability in Sinorhizobium meliloti and may play a role during the development of root nodules. Utilizing an in vivo recombination strategy, we have constructed 28 strains that contain deletions in predicted Tat substrates. Testing of these mutations for symbiotic proficiency on the plant hosts alfalfa and sweet clover shows that some of these mutations affect associations with these hosts differentially.

Inability to catabolize galactose leads to increased ability to compete for nodule occupancy in Sinorhizobium meliloti.

A mutant unable to utilize galactose was isolated in Sinorhizobium meliloti strain Rm1021. The mutation was found to be in a gene annotated dgoK1, a putative 2-keto-3-deoxygalactonokinase. The genetic region was isolated on a complementing cosmid and subsequently characterized.

Genetic characterization of a complex locus necessary for the transport and catabolism of erythritol, adonitol and L-arabitol in Sinorhizobium meliloti.

The Sinorhizobium meliloti locus necessary for the utilization of erythritol as a sole carbon source, contains 17 genes, including genes that encode an ABC transporter necessary for the transport of erythritol, as well as the genes encoding EryA, EryB, EryC, TpiB and the regulators EryD and EryR (SMc01615). Construction of defined deletions and complementation experiments show that the other genes at this locus encode products that are necessary for the catabolism of adonitol (ribitol) and l-arabitol, but not d-arabitol. These analyses show that aside from one gene that is specific for the catabolism of l-arabitol (SMc01619, lalA), the rest of the catabolic genes are necessary for both polyols (SMc01617, rbtC; SMc01618, rbtB; SMc01622, rbtA).

Glycerol utilization by Rhizobium leguminosarum requires an ABC transporter and affects competition for nodulation.

Plasmid curing has shown that the ability to use glycerol as a carbon source is plasmid-encoded in Rhizobium leguminosarum. We isolated the locus responsible for glycerol utilization from plasmid pRleVF39c in R. leguminosarum bv.