Extension of Host Range ofRhizobium leguminosarumbv.trifoliiCaused by Point Mutations innodDThat Result in Alterations in Regulatory Function and Recognition of Inducer Molecules

McIver, J.; Djordjevic, M. A.; Weinman, Jeremy J.; Bender, G. L.; Rolfe, B. G.

doi:10.1094/mpmi-2-097

Cited by 87 publications

(44 citation statements)

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“…Studies undertaken with NahR established the co-inducer-binding domain to be in the region of 268 amino acids, with a DNA-protein interaction site at residue 169 (Huang & Schell, 1991;Schell et al, 1990). Mutation-based work with NodD, CysB, AmpR and OxyR established that the residues 95, 123, 154 (NodD); 149, 165 (CysB); 102, 135 (AmpR) and 234 (OxyR) were involved in co-inducer binding/response; mutations in these regions led to a co-inducer-independent phenotype in each case (Burn et al, 1989;McIver et al, 1989;Storz et al, 1990;Bartowsky & Normark, 1991;Renna et al, 1993;Colyer & Kredich, 1994. This coinducer-independent state mimics LTTR-DNA binding in the absence of a co-inducer and effects the transcriptional activator/repressor properties of the LTTR.…”

Section: Lysr Family Transcriptional Regulatorsmentioning

confidence: 99%

Structure and function of the LysR-type transcriptional regulator (LTTR) family proteins

2008

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The LysR family of transcriptional regulators represents the most abundant type of transcriptional regulator in the prokaryotic kingdom. Members of this family have a conserved structure with an Nterminal DNA-binding helix-turn-helix motif and a C-terminal co-inducer-binding domain. Despite considerable conservation both structurally and functionally, LysR-type transcriptional regulators (LTTRs) regulate a diverse set of genes, including those involved in virulence, metabolism, quorum sensing and motility. Numerous structural and transcriptional studies of members of the LTTR family are helping to unravel a compelling paradigm that has evolved from the original observations and conclusions that were made about this family of transcriptional regulators.

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Section: Lysr Family Transcriptional Regulatorsmentioning

confidence: 99%

Structure and function of the LysR-type transcriptional regulator (LTTR) family proteins

2008

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“…viciae, NodD proteins are localized in the cytoplasmic membrane (234), where the inducing flavonoid, naringenin, also accumulates (211). Direct binding of inducers to NodD has not been demonstrated, but point mutations in nodD affect the recognition of inducing molecules and cause an extension of the host range (30,174). Furthermore, comparison of the NodD structure with various nuclear receptors has shown that the two types of proteins share conserved ligand-interacting domains located at the C-terminal end of their respective DNA-binding motifs (111).…”

Section: Flavonoids and Regulation Of Nodulation Genesmentioning

confidence: 99%

Molecular Basis of Symbiotic Promiscuity

Perret

Staehelin

Broughton

2000

Microbiol Mol Biol Rev

882

630

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SUMMARY Eukaryotes often form symbioses with microorganisms. Among these, associations between plants and nitrogen-fixing bacteria are responsible for the nitrogen input into various ecological niches. Plants of many different families have evolved the capacity to develop root or stem nodules with diverse genera of soil bacteria. Of these, symbioses between legumes and rhizobia (Azorhizobium, Bradyrhizobium, Mesorhizobium, and Rhizobium) are the most important from an agricultural perspective. Nitrogen-fixing nodules arise when symbiotic rhizobia penetrate their hosts in a strictly controlled and coordinated manner. Molecular codes are exchanged between the symbionts in the rhizosphere to select compatible rhizobia from pathogens. Entry into the plant is restricted to bacteria that have the “keys” to a succession of legume “doors”. Some symbionts intimately associate with many different partners (and are thus promiscuous), while others are more selective and have a narrow host range. For historical reasons, narrow host range has been more intensively investigated than promiscuity. In our view, this has given a false impression of specificity in legume-Rhizobium associations. Rather, we suggest that restricted host ranges are limited to specific niches and represent specialization of widespread and more ancestral promiscuous symbioses. Here we analyze the molecular mechanisms governing symbiotic promiscuity in rhizobia and show that it is controlled by a number of molecular keys.

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“…The nodD genes are found in all rhizobia but their C terminals have diverged, which enables the recognition of different flavonoids in a strain specific manner. Indeed, modification of the C terminal region resulted in alteration of host range (45,64,87). Conversely, the N terminal portion of NodD contains a helixturn-helix DNA binding domain to interact with DNA as a transcription factor.…”

Section: Determinants Of Rhizobium Symbiosismentioning

confidence: 99%

The Determinants of the Actinorhizal Symbiosis

Kucho

Hay²,

Normand³

2010

Microb. Environ.

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The actinorhizal symbiosis is a major contributor to the global nitrogen budget, playing a dominant role in ecological successions following disturbances. The mechanisms involved are still poorly known but there emerges the vision that on the plant side, the kinases that transmit the symbiotic signal are conserved with those involved in the transmission of the Rhizobium Nod signal in legumes. However, on the microbial side, complementation with Frankia DNA of Rhizobium nod mutants failed to permit identification of symbiotic genes. Furthermore, analysis of three Frankia genomes failed to permit identification of canonical nod genes and revealed symbiosis-associated genes such as nif, hup, suf and shc to be spread around the genomes. The present review explores some recently published approaches aimed at identifying bacterial symbiotic determinants.

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Extension of Host Range ofRhizobium leguminosarumbv.trifoliiCaused by Point Mutations innodDThat Result in Alterations in Regulatory Function and Recognition of Inducer Molecules

Cited by 87 publications

References 0 publications

Structure and function of the LysR-type transcriptional regulator (LTTR) family proteins

Structure and function of the LysR-type transcriptional regulator (LTTR) family proteins

Molecular Basis of Symbiotic Promiscuity

The Determinants of the Actinorhizal Symbiosis

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