Regulation of the TCA cycle and the general amino acid permease by overflow metabolism in Rhizobium leguminosarum

Walshaw, David L.; Wilkinson, Adam C.; Mundy, Mathius; Smith, Mary; Poole, Philip S.

doi:10.1099/00221287-143-7-2209

Cited by 78 publications

(79 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Nodulation of soybean plants by a sucA strain of B. japonicum, while significantly delayed and reduced, did produce bacteroids capable of nitrogen fixation at rates comparable to wild type when expressed per cell (Green and Emerich, 1997b). By contrast a sucA mutant of R. leguminosarum did not fix N 2 on peas (Walshaw et al, 1997). Thus, just as for isocitrate dehydrogenase, 2-oxoglutarate dehydrogenase mutants behave differently between B. japonicum and rhizobia that nodulate temperate legumes.…”

Section: Nitrogen Fixation and Bacteroid Metabolism Of Dicarboxylatesmentioning

confidence: 85%

“…These catalyze the oxidative decarboxylation of 2-oxoglutarate to succinyl-CoA (Green and Emerich, 1997a;Walshaw et al, 1997). Nodulation of soybean plants by a sucA strain of B. japonicum, while significantly delayed and reduced, did produce bacteroids capable of nitrogen fixation at rates comparable to wild type when expressed per cell (Green and Emerich, 1997b).…”

Section: Nitrogen Fixation and Bacteroid Metabolism Of Dicarboxylatesmentioning

confidence: 99%

See 1 more Smart Citation

Nutrient Sharing between Symbionts

White

Prell²,

James³

et al. 2007

Plant Physiology

210

158

View full text Add to dashboard Cite

In this review, we consider the exchange of nutrients between the host plant and the bacterial microsymbiont in nitrogen-fixing legume root nodules. During nodule formation, the host tissues and the bacterial microsymbiont develop in response to each other to form a specialized tissue that maintains an environment where nitrogen fixation can occur (Brewin, 2004;Mergaert et al., 2006;Prell and Poole, 2006). This complex development will not be considered here but, at the end of the process, specialized, nitrogen-fixing forms of the bacteria, known as bacteroids, reside in the plant cytosol, enclosed within plant-derived membranes. These organelle-like structures are known as symbiosomes; the plant-derived membrane that surrounds the bacteroid is the symbiosome (or peribacteroid) membrane and the space between the two is the symbiosome (or peribacteroid) space. An infected plant cell may be packed with thousands of symbiosomes. The exchange of nutrients that is fundamental to N 2 fixation therefore involves metabolism in the plant to provide carbon and nitrogen compounds to the bacteroids and to assimilate the metabolites that bacteroids release. Nutrients transferred between the symbionts must traverse both the symbiosome and the bacteroid membranes. It is clear that there is more than one pattern whereby successful nutrient exchange can take place: There are two basic types of legume nodules, determinate and indeterminate, and there are fundamental differences between the two in how they develop and in their carbon and nitrogen metabolism. This review focuses on the metabolism of carbon and nitrogen compounds in the symbionts and on the exchange of nutrients across the bacteroid and symbiosome membranes. Particular attention is paid to the movement of primary carbon and nitrogen sources and how they are utilized by both bacteroids and the plant.

show abstract

Section: Nitrogen Fixation and Bacteroid Metabolism Of Dicarboxylatesmentioning

confidence: 85%

Section: Nitrogen Fixation and Bacteroid Metabolism Of Dicarboxylatesmentioning

confidence: 99%

Nutrient Sharing between Symbionts

White

Prell²,

James³

et al. 2007

Plant Physiology

210

158

View full text Add to dashboard Cite

show abstract

“…3E) is that α-ketoglutarate can be excreted from the dme mutant of B. japonicum bacteroids. Large-scale excretion of α-ketoglutarate to culture medium has already been reported in an α-ketoglutarate dehydrogenase mutant of Rhizobium leguminosarum 30) . The accumulation of glutamate by isolated bacteroids under anaerobic conditions 18) and synthesis of α-ketoglutarate through succinic semialdehyde by α-ketoglutarate decarboxylase have been reported in B. japonicum 8) .…”

Section: Discussionmentioning

confidence: 98%

NAD-Malic Enzyme Affects Nitrogen Fixing Activity of Bradyrhizobium japonicum USDA 110 Bacteroids in Soybean Nodules

et al. 2008

View full text Add to dashboard Cite

The NAD + -dependent malic enzyme (DME) has been reported to play a key role supporting nitrogenase activity in bacteroids of Sinorhizobium meliloti. Genetic evidence for a similar role in Bradyrhizobium japonicum USDA110 was obtained by constructing a dme mutant. Soybean plants inoculated with a dme mutant did not show delayed nodulation, but formed small root nodules and exhibited significant nitrogen-deficiency symptoms. Nodule numbers and the acetylene reducting activity per nodule as a dry weight value 14 and 28 days after inoculation with the dme mutant were comparable to those of plants inoculated with wild-type B. japonicum. However, shoot dry weight and acetylene reducting activity per nodule decreased to ca. 30% of the values in plants with wild-type B. japonicum. The sucrose and organic acid (malate, succinate, acetate, α-ketoglutarate and lactate) contents of the nodules were investigated. Amounts of sucrose, malate and α-ketoglutarate increased on inoculation with the dme mutant, suggesting that the decreased DME and nitrogenase activities in the bacteroids resulted in a reduction in the consumption of these respiratory metabolites by the nodules. The data suggest that the DME activity of B. japonicum bacteroids plays a role in nodule metabolism and supports nitrogen fixation.

show abstract

“…All DNA and genetic analyses and Tn5 mutagenesis were carried out as described previously (57). Transduction was carried out using the lytic phage RL38 as previously described (7).…”

Section: Methodsmentioning

confidence: 99%

A Monocarboxylate Permease of Rhizobium leguminosarum Is the First Member of a New Subfamily of Transporters

2002

View full text Add to dashboard Cite

Amino acid transport by Rhizobium leguminosarum is dominated by two ABC transporters, the general amino acid permease (Aap) and the branched-chain amino acid permease (Bra). However, mutation of these transporters does not prevent this organism from utilizing alanine for growth. An R. leguminosarum permease (MctP) has been identified which is required for optimal growth on alanine as a sole carbon and nitrogen source. Characterization of MctP confirmed that it transports alanine (K m ‫؍‬ 0.56 mM) and other monocarboxylates such as lactate and pyruvate (K m ‫؍‬ 4.4 and 3.8 M, respectively). Uptake inhibition studies indicate that propionate, butyrate, ␣-hydroxybutyrate, and acetate are also transported by MctP, with the apparent affinity for solutes demonstrating a preference for C 3 -monocarboxylates. MctP has significant sequence similarity to members of the sodium/solute symporter family. However, sequence comparisons suggest that it is the first characterized permease of a new subfamily of transporters. While transport via MctP was inhibited by CCCP, it was not apparently affected by the concentration of sodium. In contrast, glutamate uptake in R. leguminosarum by the Escherichia coli GltS system did require sodium, which suggests that MctP may be proton coupled. Uncharacterized members of this new subfamily have been identified in a broad taxonomic range of species, including proteobacteria of the ␤-subdivision, gram-positive bacteria, and archaea. A two-component sensor-regulator (MctSR), encoded by genes adjacent to mctP, is required for activation of mctP expression.Rhizobium leguminosarum is a member of a group of ␣-subdivision of the proteobacteria (the rhizobia), which form a species-specific symbiotic relationship with leguminous plants in order to fix atmospheric nitrogen. The plant supplies the bacteroid (symbiotic bacteria) with a carbon source (C 4 -dicarboxylic acid), while the plant receives reduced nitrogen from the bacteroid. Other rhizobia include Rhizobium, Mesorhizobium, Sinorhizobium, Bradyrhizobium, and Azorhizobium species (8,33,53). Prior to establishing a Rhizobium-legume symbiosis, bacteria must thrive in the soil environment, competing with many organisms for nutrients. Transporters of key nutrients, such as amino acids, may give a competitive advantage to rhizobia, allowing them to better colonize roots. This may account for the large number of transporters that have been revealed by the completed genome sequences of Sinorhizobium meliloti, Mesorhizobium loti, and Agrobacterium tumefaciens (13,26,59).Amino acid transport by R. leguminosarum is dominated by two permeases of the ABC transporter superfamily, the general amino acid permease (Aap) and the branched-chain amino acid permease (Bra). Aap and Bra are members of the polar amino acid transporter (transport classification [T.C.] number 3.A.1.3) and hydrophobic amino acid transporter (T.C. number 3.A.1.4) families, respectively (21, 44). However, both are atypical as they transport a broad range of amino acids (19,56). Indeed, Br...

show abstract

Regulation of the TCA cycle and the general amino acid permease by overflow metabolism in Rhizobium leguminosarum

Cited by 78 publications

References 69 publications

Nutrient Sharing between Symbionts

Nutrient Sharing between Symbionts

NAD-Malic Enzyme Affects Nitrogen Fixing Activity of Bradyrhizobium japonicum USDA 110 Bacteroids in Soybean Nodules

A Monocarboxylate Permease of Rhizobium leguminosarum Is the First Member of a New Subfamily of Transporters

Contact Info

Product

Resources

About