scholarly journals Competitive Nodulation Blocking of cv. Afghanistan Pea Is Related to High Levels of Nodulation Factors Made by Some Strains of Rhizobium leguminosarum bv. viciae

2002 ◽  
Vol 15 (1) ◽  
pp. 60-68 ◽  
Author(s):  
Bridget Hogg ◽  
Andrea E. Davies ◽  
Karen E. Wilson ◽  
Ton Bisseling ◽  
J. Allan Downie
Keyword(s):  
Gene Expression ◽  
Host Specificity ◽  
Rhizobium Leguminosarum ◽  
Gene Region ◽  
Nod Factors ◽  
Nod Factor ◽  
Present Evidence ◽  
Factor Production ◽  
Nodulation Factors ◽  
Nod Gene Expression

Cultivar Afghanistan peas are resistant to nodulation by many strains of Rhizobium leguminosarum bv. viciae but are nodulated by strain TOM, which carries the host specificity gene nodX. Some strains that lack nodX can inhibit nodulation of cv. Afghanistan by strain TOM. We present evidence that this “competitive nodulation-blocking” (Cnb) phenotype may result from high levels of Nod factors inhibiting nodulation of cv. Afghanistan peas. The TOM nod gene region (including nodX) is cloned on pIJ1095, and strains (including TOM itself) carrying pIJ1095 nodulate cv. Afghanistan peas very poorly but can nodulate other varieties normally. The presence of pIJ1095, which causes increased levels of Nod factor production, correlates with Cnb. Nodulation of cv. Afghanistan by TOM is also inhibited by a cloned nodD gene that increases nod gene expression and Nod factor production. Nodulation of cv. Afghanistan can be stimulated if nodD on pIJ1095 is mutated, thus severely reducing the level of Nod factor produced. Repression of nod gene expression by nolR eliminates the Cnb phenotype and can stimulate nodulation of cv. Afghanistan. Addition of Nod factors to cv. Afghanistan roots strongly inhibits nodulation. The Cnb+ strains and added Nod factors inhibit infection thread initiation by strain TOM. The sym2A allele determines resistance of cv. Afghanistan to nodulation by strains of R. leguminosarum bv. viciae lacking nodX. We tested whether sym2A is involved in Cnb by using a pea line carrying the sym2A region introgressed from cv. Afghanistan; nodulation in the introgressed line was inhibited by Cnb+ strains. Therefore, the sym2A region has an effect on Cnb, although another locus (or loci) may contribute to the stronger Cnb seen in cv. Afghanistan.

scholarly journals Nod Factor-Induced Expression of Leghemoglobin to Study the Mechanism of NH4NO3 Inhibition on Root Hair Deformation

1997 ◽  
Vol 10 (2) ◽  
pp. 215-220 ◽  
Author(s):  
Renze Heidstra ◽  
Gerd Nilsen ◽  
Francisco Martinez-Abarca ◽  
Ab van Kammen ◽  
Ton Bisseling
Keyword(s):  
Gene Expression ◽  
Root Hair ◽  
Rhizobium Leguminosarum ◽  
Cortical Cell ◽  
Brefeldin A ◽  
Marker Genes ◽  
Nodule Formation ◽  
Cdna Clones ◽  
Nod Factor ◽  
Root Hair Deformation

Nod factors secreted by Rhizobium leguminosarum bv. viciae induce root hair deformation, the formation of nodule primordia, and the expression of early nodulin genes in Vicia sativa (vetch). Root hair deformation is induced within 3 h in a small, susceptible zone (±2 mm) of the root. NH4NO3, known to be a potent blocker of nodule formation, inhibits root hair deformation, initial cortical cell divisions, and infection thread formation. To test whether NH4NO3 affects the formation of a component of the Nod factor perception-transduction system, we studied Nod factor-induced gene expression. The differential display technique was used to search for marker genes, which are induced within 1 to 3 h after Nod factor application. Surprisingly, one of the isolated cDNA clones was identified as a leghemoglobin gene (VsLb1), which is induced in vetch roots within 1 h after Nod factor application. By using the drug brefeldin A, it was then shown that VsLb1 activation does not require root hair deformation. The pVsLb1 clone was used as a marker to show that in vetch plants grown in the presence of NH4NO3 Nod factor perception and transduction leading to gene expression are unaffected.

scholarly journals Natural Variation in Host-Specific Nodulation of Pea Is Associated with a Haplotype of the SYM37 LysM-Type Receptor-Like Kinase

2011 ◽  
Vol 24 (11) ◽  
pp. 1396-1403 ◽  
Author(s):  
Ronghui Li ◽  
Maggie R. Knox ◽  
Anne Edwards ◽  
Bridget Hogg ◽  
T. H. Noel Ellis ◽  
...  
Keyword(s):  
Natural Variation ◽  
Rhizobium Leguminosarum ◽  
Recombinant Inbred Lines ◽  
Acyl Chain ◽  
Introgression Line ◽  
Nod Factors ◽  
Nod Factor ◽  
Group I ◽  
Receptor Like Kinase ◽  
Type Receptor

Rhizobium leguminosarum bv. viciae, which nodulates pea and vetch, makes a mixture of secreted nodulation signals (Nod factors) carrying either a C18:4 or a C18:1 N-linked acyl chain. Mutation of nodE blocks the formation of the C18:4 acyl chain, and nodE mutants, which produce only C18:1-containing Nod factors, are less efficient at nodulating pea. However, there is significant natural variation in the levels of nodulation of different pea cultivars by a nodE mutant of R. leguminosarum bv. viciae. Using recombinant inbred lines from two pea cultivars, one which nodulated relatively well and one very poorly by the nodE mutant, we mapped the nodE-dependent nodulation phenotype to a locus on pea linkage group I. This was close to Sym37 and PsK1, predicted to encode LysM-domain Nod-factor receptor-like proteins; the Sym2 locus that confers Nod-factor-specific nodulation is also in this region. We confirmed the map location using an introgression line carrying this region. Our data indicate that the nodE-dependent nodulation is not determined by the Sym2 locus. We identified several pea lines that are nodulated very poorly by the R. leguminosarum bv. viciae nodE mutant, sequenced the DNA of the predicted LysM-receptor domains of Sym37 and PsK1, and compared the sequences with those derived from pea cultivars that were relatively well nodulated by the nodE mutant. This revealed that one haplotype (encoding six conserved polymorphisms) of Sym37 is associated with very poor nodulation by the nodE mutant. There was no such correlation with polymorphisms at the PsK1 locus. We conclude that the natural variation in nodE-dependent nodulation in pea is most probably determined by the Sym37 haplotype.

scholarly journals Photosynthetic Bradyrhizobium Sp. Strain ORS285 Synthesizes 2-O-Methylfucosylated Lipochitooligosaccharides for nod Gene–Dependent Interaction with Aeschynomene Plants

2011 ◽  
Vol 24 (12) ◽  
pp. 1440-1447 ◽  
Author(s):  
Adeline Renier ◽  
Fabienne Maillet ◽  
Joel Fardoux ◽  
Véréna Poinsot ◽  
Eric Giraud ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bradyrhizobium Japonicum ◽  
Culture Supernatant ◽  
Photosynthetic Bacterium ◽  
Lacz Reporter ◽  
Symbiotic Interaction ◽  
Nod Factor ◽  
Bradyrhizobium Sp ◽  
Nod Gene Expression ◽  
Dependent Interaction

Bradyrhizobium sp. strain ORS285 is a photosynthetic bacterium that forms nitrogen-fixing nodules on the roots and stems of tropical aquatic legumes of the Aeschynomene genus. The symbiotic interaction of Bradyrhizobium sp. strain ORS285 with certain Aeschynomene spp. depends on the presence of nodulation (nod) genes whereas the interaction with other species is nod gene independent. To study the nod gene-dependent molecular dialogue between Bradyrhizobium sp. strain ORS285 and Aeschynomene spp., we used a nodB-lacZ reporter strain to monitor the nod gene expression with various flavonoids. The flavanones liquiritigenin and naringenin were found to be the strongest inducers of nod gene expression. Chemical analysis of the culture supernatant of cells grown in the presence of naringenin showed that the major Nod factor produced by Bradyrhizobium sp. strain ORS285 is a modified chitin pentasaccharide molecule with a terminal N-C18:1-glucosamine and with a 2-O-methyl fucose linked to C-6 of the reducing glucosamine. In this respect, the Bradyrhizobium sp. strain ORS285 Nod factor is the same as the major Nod factor produced by the nonphotosynthetic Bradyrhizobium japonicum USDA110 that nodulates the roots of soybean. This suggests a classic nod gene-dependent molecular dialogue between Bradyrhizobium sp. strain ORS285 and certain Aeschynomene spp. This is supported by the fact that B. japonicum USDA110 is able to form N2-fixing nodules on both the roots and stems of Aeschynomene afraspera.

Ethylene provides positional information on cortical cell division but is not involved in Nod factor-induced root hair tip growth in Rhizobium-legume interaction

Development ◽  
1997 ◽  
Vol 124 (9) ◽  
pp. 1781-1787 ◽  
Author(s):  
R. Heidstra ◽  
W.C. Yang ◽  
Y. Yalcin ◽  
S. Peck ◽  
A.M. Emons ◽  
...  
Keyword(s):  
Cell Division ◽  
Root Hair ◽  
Rhizobium Leguminosarum ◽  
Tip Growth ◽  
Cortical Cell ◽  
Acc Oxidase ◽  
Positional Information ◽  
Nod Factors ◽  
Nod Factor ◽  
Root Hair Deformation

Nod factors secreted by Rhizobium leguminosarum bv. viciae induce root hair deformation, involving a reinitiation of tip growth, and the formation of nodule primordia in Vicia sativa (vetch). Ethylene is a potent inhibitor of cortical cell division, an effect that can be counteracted by applying silver ions (Ag+) or aminoethoxy-vinylglycine (AVG). In contrast to the inhibitory effect on cortical cell division, ethylene promotes the formation of root hairs (which involves tip growth) in the root epidermis of Arabidopsis. We investigate the possible paradox concerning the action of ethylene, putatively promoting Nod factor induced tip growth whilst, at the same time, inhibiting cortical cell division. We show, by using the ethylene inhibitors AVG and Ag+, that ethylene has no role in the reinitiation of root hair tip growth induced by Nod factors (root hair deformation) in vetch. However, root hair formation is controlled, at least in part, by ethylene. Furthermore, we show that ACC oxidase, which catalizes the last step in ethylene biosynthesis, is expressed in the cell layers opposite the phloem in that part of the root where nodule primordia are induced upon inoculation with Rhizobium. Therefore, we test whether endogenously produced ethylene provides positional information controlling the site where nodule primordia are formed by determining the position of nodules formed on pea roots grown in the presence of AVG or Ag+.

Attachment of IR-active organometallic probe groups to flavonoid inducers of nod gene expression

1999 ◽  
Vol 589 (1) ◽  
pp. 103-110 ◽  
Author(s):  
Andrej V Malkov ◽  
Ljubica Mojovic ◽  
G.Richard Stephenson ◽  
Andrew T Turner ◽  
Colin S Creaser
Keyword(s):  
Gene Expression ◽  
Nod Gene Expression

Dpp signaling thresholds in the dorsal ectoderm of the Drosophila embryo

Development ◽  
2000 ◽  
Vol 127 (15) ◽  
pp. 3305-3312 ◽  
Author(s):  
H.L. Ashe ◽  
M. Mannervik ◽  
M. Levine
Keyword(s):  
Gene Expression ◽  
Target Genes ◽  
Histone Acetyltransferase ◽  
Cell Types ◽  
Drosophila Embryo ◽  
Present Evidence ◽  
Drosophila Homolog ◽  
Dorsal Ectoderm ◽  
Transgenic Embryos ◽  
Different Cell Types

The dorsal ectoderm of the Drosophila embryo is subdivided into different cell types by an activity gradient of two TGF(β) signaling molecules, Decapentaplegic (Dpp) and Screw (Scw). Patterning responses to this gradient depend on a secreted inhibitor, Short gastrulation (Sog) and a newly identified transcriptional repressor, Brinker (Brk), which are expressed in neurogenic regions that abut the dorsal ectoderm. Here we examine the expression of a number of Dpp target genes in transgenic embryos that contain ectopic stripes of Dpp, Sog and Brk expression. These studies suggest that the Dpp/Scw activity gradient directly specifies at least three distinct thresholds of gene expression in the dorsal ectoderm of gastrulating embryos. Brk was found to repress two target genes, tailup and pannier, that exhibit different limits of expression within the dorsal ectoderm. These results suggest that the Sog inhibitor and Brk repressor work in concert to establish sharp dorsolateral limits of gene expression. We also present evidence that the activation of Dpp/Scw target genes depends on the Drosophila homolog of the CBP histone acetyltransferase.

scholarly journals BOX Elements Modulate Gene Expression in Streptococcus pneumoniae: Impact on the Fine-Tuning of Competence Development

2006 ◽  
Vol 188 (23) ◽  
pp. 8307-8312 ◽  
Author(s):  
Eivind Knutsen ◽  
Ola Johnsborg ◽  
Yves Quentin ◽  
Jean-Pierre Claverys ◽  
Leiv Sigve Håvarstein
Keyword(s):  
Gene Expression ◽  
Genetic Diversity ◽  
Streptococcus Pneumoniae ◽  
Competence Development ◽  
Fine Tuning ◽  
Present Evidence ◽  
Genomic Plasticity ◽  
Affect Expression ◽  
Intergenic Regions

ABSTRACT More than 100 BOX elements are randomly distributed in intergenic regions of the pneumococcal genome. Here we demonstrate that these elements can affect expression of neighboring genes and present evidence that they are mobile. Together, our findings show that BOX elements enhance genetic diversity and genomic plasticity in Streptococcus pneumoniae.

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