scholarly journals Biological activity of Nod factors

2020 ◽  
Author(s):  
Dominika Kidaj ◽  
Mikolaj Krysa ◽  
Katarzyna Susniak ◽  
Joanna Matys ◽  
Iwona Komaniecka ◽  
...  
Keyword(s):  
Molecular Level ◽  
Root Nodules ◽  
Cortical Cell ◽  
Plant Tissues ◽  
Nod Factors ◽  
Nod Factor ◽  
Expression Of Genes ◽  
Root Hair Deformation ◽  
Low Concentrations ◽  
Genes Encoding

Chemically, the Nod factors (NFs) are lipochitooligosaccharides, produced mainly by bacteria of the Rhizobium genus. They are the main signaling molecules involved in the initiation of symbiosis between rhizobia and legume plants. Nod factors affect plant tissues at very low concentrations, even as low as 10–12 mol/L. They induce root hair deformation, cortical cell division, and root nodules’ formation in the host plant. At the molecular level, the cytoskeleton is reorganized and expression of genes encoding proteins called nodulins is induced in response to Nod factors in the cell. Action of Nod factors is highly specific because it depends on the structure of a particular Nod factor involved, as well as the plant receptor reacting with it.

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+.

scholarly journals Basal anti-inflammatory responses in cultured endothelial cells exposed to two conjugated linoleic acids

2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Carina Valenzuela ◽  
Elizabeth Miles ◽  
Philip Calder
Keyword(s):  
Inflammatory Responses ◽  
Adhesion Assay ◽  
Dependent Manner ◽  
Relative Expression ◽  
Inflammatory Pathways ◽  
Expression Of Genes ◽  
Low Concentrations ◽  
Genes Encoding ◽  
Anti Inflammatory ◽  
Pre Treatment

AbstractConjugated linoleic acid (CLA) isomers have been shown to possess anti-atherosclerotic properties, which may be related to the downregulation of inflammatory pathways. Whether low concentrations of CLAs are able to affect basal, unstimulated endothelial cell (EC) responses is not clear. The aim of this study was to evaluate the effects of two CLAs (cis-9, trans-11 and trans-10, cis-12) on basal inflammatory responses by ECs.EA.hy926 cells (HUVEC lineage) were cultured under standard conditions and exposed to CLAs (1 and 10 μM) for 48 hours. MTT assay was performed to determine cell viability; incorporation of FA was confirmed by gas chromatography; inflammatory mediators were assessed by multiplex immunoassay; the relative expression of genes encoding transcription factors and inflammatory cytokines was assessed through real-time PCR and static adhesion assay was used to evaluate monocyte attachment to the EC monolayer.CLAs were incorporated into ECs in a dose-dependent manner. Pre-treatment with CLA9,11 (1 uM) significantly reduced unstimulated, basal concentrations of MCP-1 (p < 0.05), and CLA10,12 at 10 uM had the same effect (p < 0.05). Both CLAs at 10 uM increased the relative expression of NFκβ (p < 0.01 and p < 0.05, respectively), while decreasing the relative expression of PPARα (p < 0.0001), COX-2 (p < 0.0001) and IL-6 (p < 0.0001). In contrast, no effect was observed in the adhesion assay for either CLA.These results suggest that both CLAs at a low concentration have a neutral or modest anti-inflammatory effect in basal conditions, which may influence endothelial function and risk of vascular disease. Interestingly, at these low CLA concentrations some pro-inflammatory genes are upregulated while others are down regulated. This suggests complex effects of CLAs on inflammatory pathways.

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 Identical Accumulation and Immobilization of Sulfated and Nonsulfated Nod Factors in Host and Nonhost Root Hair Cell Walls

2003 ◽  
Vol 16 (10) ◽  
pp. 884-892 ◽  
Author(s):  
Joachim Goedhart ◽  
Jean-Jacques Bono ◽  
Ton Bisseling ◽  
Theodorus W. J. Gadella
Keyword(s):  
Hair Cell ◽  
Root Hair ◽  
Cell Walls ◽  
Root Hairs ◽  
Sharp Decrease ◽  
Biologically Active ◽  
Nod Factors ◽  
Nod Factor ◽  
Root Hair Cell ◽  
Root Hair Deformation

Nod factors are signaling molecules secreted by Rhizobium bacteria. These lipo-chitooligosaccharides (LCOs) are required for symbiosis with legumes and can elicit specific responses at subnanomolar concentrations on a compatible host. How plants perceive LCOs is unclear. In this study, using fluorescent Nod factor analogs, we investigated whether sulfated and nonsulfated Nod factors were bound and perceived differently by Medicago truncatula and Vicia sativa root hairs. The bioactivity of three novel sulfated fluorescent LCOs was tested in a root hair deformation assay on M. truncatula, showing bioactivity down to 0.1 to 1 nM. Fluorescence microscopy of plasmolyzed M. truncatula root hairs shows that sulfated fluorescent Nod factors accumulate in the cell wall of root hairs, whereas they are absent from the plasma membrane when applied at 10 nM. When the fluorescent Nod factor distribution in medium surrounding a root was studied, a sharp decrease in fluorescence close to the root hairs was observed, visualizing the remarkable capacity of root hairs to absorb Nod factors from the medium. Fluorescence correlation microscopy was used to study in detail the mobilities of sulfated and nonsulfated fluorescent Nod factors which are biologically active on M. truncatula and V. sativa, respectively. Remarkably, no difference between sulfated and nonsulfated Nod factors was observed: both hardly diffuse and strongly accumulate in root hair cell walls of both M. truncatula and V. sativa. The implications for the mode of Nod factor perception are discussed.

scholarly journals A plant chitinase controls cortical infection thread progression and nitrogen-fixing symbiosis

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Anna Malolepszy ◽  
Simon Kelly ◽  
Kasper Kildegaard Sørensen ◽  
Euan Kevin James ◽  
Christina Kalisch ◽  
...  
Keyword(s):  
Root Nodules ◽  
Lotus Japonicus ◽  
Positional Information ◽  
Dependent Manner ◽  
Nitrogen Fixing ◽  
Nod Factors ◽  
Nod Factor ◽  
Infection Threads ◽  
Bacterial Mutants ◽  
Multicellular Organisms

Morphogens provide positional information and their concentration is key to the organized development of multicellular organisms. Nitrogen-fixing root nodules are unique organs induced by Nod factor-producing bacteria. Localized production of Nod factors establishes a developmental field within the root where plant cells are reprogrammed to form infection threads and primordia. We found that regulation of Nod factor levels by Lotus japonicus is required for the formation of nitrogen-fixing organs, determining the fate of this induced developmental program. Our analysis of plant and bacterial mutants shows that a host chitinase modulates Nod factor levels possibly in a structure-dependent manner. In Lotus, this is required for maintaining Nod factor signalling in parallel with the elongation of infection threads within the nodule cortex, while root hair infection and primordia formation are not influenced. Our study shows that infected nodules require balanced levels of Nod factors for completing their transition to functional, nitrogen-fixing organs.

The pleiotropic effects of extract containing rhizobial Nod factors on pea growth and yield

2014 ◽  
Vol 9 (4) ◽  
pp. 396-409 ◽  
Author(s):  
Janusz Podleśny ◽  
Jerzy Wielbo ◽  
Anna Podleśna ◽  
Dominika Kidaj
Keyword(s):  
Foliar Application ◽  
Root Nodules ◽  
Growth Dynamics ◽  
Net Photosynthesis ◽  
Growth Stimulation ◽  
Dry Mass ◽  
Growth And Yield ◽  
Nod Factors ◽  
Nod Factor ◽  
Beneficial Effects

AbstractRhizobial lipochitooligosacharides (Nod factors) influence the development of legume roots, including growth stimulation, nodule induction and root hair curling. However, their effect on the green parts of plants is less known, therefore we evaluated seed and foliar application of an extract containing Nod factors on pea growth and yield. Pea plants were examined from emergence to full maturity, including growth dynamics and morphological (nodule number and weight, the quantity and surface area of leaves) or physiological (photosynthesis and transpiration intensity, chlorophyll and nitrogen content) parameters. The foliar application Nod factor extract, or seed dressing followed by foliar application, resulted in the best outcomes. The number and weight of root nodules, the chlorophyll content in leaves, and the intensity of net photosynthesis were all elevated. As a consequence of Nod factor treatment, the dynamics of dry mass accumulation of pea organs were improved and the pod number was increased. A significant increase in pea yield was observed after Nod factor application. Increase of nodule and pod numbers and improved growth of roots appear to be amongst the beneficial effects of Nod factor extract on the activation of secondary plant meristems.

scholarly journals Evidence for the Involvement in Nodulation of the Two Small Putative Regulatory Peptide-Encoding Genes MtRALFL1 and MtDVL1

2008 ◽  
Vol 21 (8) ◽  
pp. 1118-1127 ◽  
Author(s):  
Jean-Philippe Combier ◽  
Helge Küster ◽  
Etienne-Pascal Journet ◽  
Natalija Hohnjec ◽  
Pascal Gamas ◽  
...  
Keyword(s):  
Nodule Development ◽  
Strong Increase ◽  
Nod Factors ◽  
Plant Host ◽  
Symbiotic Interaction ◽  
Nod Factor ◽  
Infection Threads ◽  
Genes Encoding ◽  
Supernodulating Mutant ◽  
Increased Sensitivity

Nod factors are key bacterial signaling molecules regulating the symbiotic interaction between bacteria known as rhizobia and leguminous plants. Studying plant host genes whose expression is affected by Nod factors has given insights into early symbiotic signaling and development. Here, we used a double supernodulating mutant line that shows increased sensitivity to Nod factors to study the Nod factor-regulated transcriptome. Using microarrays containing more than 16,000 70-mer oligonucleotide probes, we identified 643 Nod-factor-regulated genes, including 225 new Nod-factor-upregulated genes encoding many potential regulators. Among the genes found to be Nod factor upregulated, we identified and characterized MtRALFL1 and MtDVL1, which code for two small putative peptide regulators of 135 and 53 amino acids, respectively. Expression analysis confirmed that these genes are upregulated during initial phases of nodulation. Overexpression of MtRALFL1 and MtDVL1 in Medicago truncatula roots resulted in a marked reduction in the number of nodules formed and in a strong increase in the number of aborted infection threads. In addition, abnormal nodule development was observed when MtRALFL1 was overexpressed. This work provides evidence for the involvement of new putative small-peptide regulators during nodulation.

Expression of genes encoding PR10 class pathogenesis-related proteins is inhibited in yellow lupine root nodules

Plant Science ◽  
1999 ◽  
Vol 149 (2) ◽  
pp. 125-137 ◽  
Author(s):  
Michał M Sikorski ◽  
Jacek Biesiadka ◽  
Alina E Kasperska ◽  
Joanna Kopcińska ◽  
Barbara Łotocka ◽  
...  
Keyword(s):  
Root Nodules ◽  
Pathogenesis Related Proteins ◽  
Expression Of Genes ◽  
Pathogenesis Related ◽  
Genes Encoding ◽  
Yellow Lupine ◽  
Related Proteins

scholarly journals Comparative analysis of the expression of stress-related genes in two pea genotypes contrasting in tolerance to cadmium

2018 ◽  
Vol 16 (4) ◽  
pp. 75-84
Author(s):  
Olga A. Kulaeva ◽  
Emma S. Gribchenko ◽  
Evgeny A. Zorin ◽  
Marina S. Kliukova ◽  
Vladimir A. Zhukov
Keyword(s):  
Comparative Analysis ◽  
Molecular Level ◽  
Toxic Substances ◽  
Expression Of Genes ◽  
Number Of Genes ◽  
Genes Encoding ◽  
Genetic Mechanisms ◽  
Stress Related Genes ◽  
Tolerance To Cadmium ◽  
Initial Line

Background. A major problem of the environmental pollution with heavy metals, including cadmium, requires an intensive study of the molecular and genetic mechanisms underlying the tolerance of plants to these toxic substances. In this study we present a comparative analysis of the expression of stress-related genes in two pea genotypes contrasting in tolerance to cadmium. Materials and methods. A unique mutant of pea SGECdt, characterized by the increased tolerance to cadmium, and initial line SGE were used. Gene expression was analyzed by Real Time PCR. Results. In the line SGE cadmium increase the expression of genes, encoding catalase, chitinase, chitinase-like protein PRP4A and dirigent protein PI206. In the mutant SGECdt cadmium increase the expression of genes, encoding chitinase, glutathione reductase and defensin DRR230. In control samples expression of genes encoding PRP4A and DRRR230 was enhanced in mutant SGECdt versus line SGE. Conclusion. It was shown that, the reaction of the mutant SGECdt at the molecular level differs from that of the line SGE. In the mutant SGECdt, a change in the expression of a number of genes is observed, which may indicate that cadmium entering the cell causes activation of defense reactions.

Root nodulation of Sesbania rostrata suppresses stem nodulation by Sinorhizobium teranga but not Azorhizobium caulinodans

1996 ◽  
Vol 42 (2) ◽  
pp. 187-190 ◽  
Author(s):  
Kodjo Tomekpe ◽  
Marcelle Holsters ◽  
Bernard Dreyfus
Keyword(s):  
Host Plant ◽  
Root Nodules ◽  
Sesbania Rostrata ◽  
Efficient Production ◽  
Nod Factors ◽  
Azorhizobium Caulinodans ◽  
Experimental Conditions ◽  
Nod Factor ◽  
Stem Nodulation ◽  
Azorhizobium Caulinodans Ors571

Azorhizobium caulinodans ORS571 and Sinorhizobium teranga ORS51 and ORS52 are symbionts of the same host plant Sesbania rostrata. In nature, A. caulinodans nodulates more competitively the stem-located infection sites of Sesbania rostrata. Sinorhizobium strains, although frequently present in root nodules, are seldom found in stem nodules. One probable explanation for this phenomenon is the more abundant presence of Azorhizobium on the leaf and stem surfaces of the host plant. Work presented here hints at other plausible factors that determine the greater "stem specificity" of Azorhizobium. We found that under experimental conditions in which roots are not inoculated, all strains nodulated stems very well. However, ORS51 and ORS52 were much more sensitive than ORS571 to suppression of stem nodulation by previous root inoculation. The introduction of the regulatory nodD gene from A. caulinodans diminished the sensitivity to this suppression, probably by enhanced nod gene expression and subsequent Nod factor production. Our hypothesis is that the greater infectivity of ORS571 is due to a more efficient production of mitogenic Nod factors at stem-located infection sites, thereby more readily overcoming systemic suppression caused by previous root inoculations.Key words: autoregulation, nitrogen fixation, rhizobial ecology, systemic suppression of nodulation.

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