scholarly journals Induction of Chalcone Synthase Expression by Rhizobia and Nod factors in Root Hairs and Roots

1997 ◽  
Vol 10 (3) ◽  
pp. 388-393 ◽  
Author(s):  
Andrea Krause ◽  
Vo T. T. Lan ◽  
William J. Broughton
Keyword(s):  
Chalcone Synthase ◽  
Root Hairs ◽  
Signal Transduction Pathway ◽  
Defense Responses ◽  
Nod Factors ◽  
Nod Factor ◽  
Transcript Levels ◽  
Gene Transcripts ◽  
Infection Pathway ◽  
Rhizobium Sp

Chalcone synthase (CHS) of Vigna unguiculata is encoded by a gene family that is abundantly transcribed in leaves and nodules. Inoculation with Rhizobium sp. NGR234, which nodulates V. unguiculata, or with NGRΔnodABC, a mutant deficient in Nod factor production, induced rapid accumulation of CHS mRNAs in roots and root hairs. As both Nod+ and Nod- bacteria provoke responses, induction of CHS gene expression may involve symbiotic or defense responses. Four days after inoculation with the wild-type Rhizobium sp., the transcript levels increased in roots but decreased in root hairs. Use of a region unique to the 5′ end of a specific CHS gene (VuCHS1) showed that increases of transcript levels in root hairs 24 h after inoculation with both rhizobia were specific to this gene. Transcripts of this gene in roots were only detectable 4 days after treatment with NGR234. It is possible therefore that accumulation of VuCHS1 follows the infection pathway of rhizobia entering legume roots. Purified Nod factors induced accumulation of transcripts, showing that they might be part of the signal transduction pathway leading to CHS expression.

Differential accumulation of plant defense gene transcripts in a compatible and an incompatible plant-pathogen interaction

1986 ◽  
Vol 6 (5) ◽  
pp. 1615-1623
Author(s):  
J N Bell ◽  
T B Ryder ◽  
V P Wingate ◽  
J A Bailey ◽  
C J Lamb
Keyword(s):  
Plant Defense ◽  
Phenylalanine Ammonia Lyase ◽  
Chalcone Synthase ◽  
Defense Responses ◽  
Infected Tissue ◽  
Colletotrichum Lindemuthianum ◽  
Specific Interactions ◽  
Defense Gene ◽  
Sequence Of Events ◽  
Gene Transcripts

Phenylalanine ammonia-lyase and chalcone synthase catalyze the first reaction of phenylpropanoid biosynthesis and the first reaction of a branch pathway specific for flavonoid-isoflavonoid biosynthesis, respectively. These enzymes are key control elements in the synthesis of kievitone, phaseollin, and related isoflavonoid-derived phytoalexins. RNA blot hybridization with 32P-labeled cDNA sequences was used to demonstrate marked accumulation of phenylalanine ammonia-lyase and chalcone synthase mRNAs in excision-wounded hypocotyls of Phaseolus vulgaris L. (dwarf French bean) and during race-cultivar-specific interactions between hypocotyls of P. vulgaris and the partially biotrophic fungus Colletotrichum lindemuthianum, the causal agent of anthracnose. In an incompatible interaction (host resistant), early concomitant accumulation of phenylalanine ammonia-lyase and chalcone synthase mRNAs, localized mainly but not entirely in tissue adjacent to the site of infection, was observed prior to the onset of phytoalexin accumulation and expression of localized, hypersensitive resistance. In contrast, in a compatible interaction (host susceptible) there was no early accumulation of these transcripts; instead, there was a delayed widespread response associated with phytoalexin accumulation during attempted lesion limitation. Two-dimensional gel electrophoresis of [35S]methionine-labeled polypeptides synthesized in vitro by translation of isolated polysomal RNA demonstrated stimulation of the synthesis of characteristic sets of phenylalanine ammonia-lyase and chalcone synthase isopolypeptides in directly infected tissue and distant, hitherto uninfected tissue in both compatible and incompatible interactions. Our data show that specific accumulation of plant defense gene transcripts is a key early component in the sequence of events leading to expression of defense responses in wounded tissue and in infected tissue during race-cultivar-specific interactions and that an elicitation signal is transmitted intercellularly in response to infection.

scholarly journals Rhizobium Nod Factors Induce an Increase in Sub-apical Fine Bundles of Actin Filaments in Vicia sativa Root Hairs within Minutes

1999 ◽  
Vol 12 (9) ◽  
pp. 829-832 ◽  
Author(s):  
Norbert C. A. de Ruijter ◽  
Ton Bisseling ◽  
Anne Mie C. Emons
Keyword(s):  
Actin Cytoskeleton ◽  
Actin Filaments ◽  
Tip Growth ◽  
Developmental Stages ◽  
Root Hairs ◽  
Vicia Sativa ◽  
Nod Factors ◽  
Nod Factor

We studied the response of the actin cytoskeleton in vetch root hairs after application of host-specific Nod factor. Within 3 to 15 min, the number of sub-apical fine bundles of actin filaments (FB-actin) increased in all developmental stages. Tip growth resumed only in hairs in which the FB-actin density and the length of the region with FB-actin exceeded a minimal value.

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.

A Putative Role for Fusaric Acid in Biocontrol of the Parasitic Angiosperm Orobanche ramosa

2006 ◽  
Vol 19 (5) ◽  
pp. 550-556 ◽  
Author(s):  
Brahim Bouizgarne ◽  
Hayat El-Maarouf-Bouteau ◽  
Karine Madiona ◽  
Bernadette Biligui ◽  
Michèle Monestiez ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Plant Defense ◽  
Fusaric Acid ◽  
Root Hairs ◽  
Signal Transduction Pathway ◽  
Defense Responses ◽  
Plant Defense Responses ◽  
Fusarium Spp ◽  
Membrane Hyperpolarization ◽  
Orobanche Ramosa

Fusarium spp. are ubiquitous fungi found in soil worldwide as both pathogenic and nonpathogenic strains. The signals leading to disease or the absence of disease are poorly understood. We recently showed that fusaric acid (FA), a nonspecific toxin produced by most Fusarium spp., could elicit various plant defense responses at 100 nM without toxic effect. In this study, we checked for the effect of FA on root and root hairs, probable first site of contact between the fungi and the host. Large FA concentrations reduce root and root-hair growth and induce a rapid transient membrane hyperpolarization, followed by a large depolarization, due to the inhibition of H+-ATPase currents. Nanomolar concentrations of FA induced only an early transient membrane hyperpolarization of root hairs compatible with the induction of a signal transduction pathway. FA at 10-7 M failed to induce salicylic acid- and jasmonic acid/ethylene-dependent defense-related genes but inhibited the germination of the angiosperm parasite Orobanche ramosa in contact of FA-pretreated Arabidopsis thaliana seedlings. These data suggest that FA at nontoxic concentrations could activate signal transduction components necessary for plant-defense responses that could contribute to biocontrol activity of Fusarium spp.

Syringolin-Mediated Activation of the Pir7b Esterase Gene in Rice Cells Is Suppressed by Phosphatase Inhibitors

2000 ◽  
Vol 13 (3) ◽  
pp. 342-346 ◽  
Author(s):  
Paul Hassa ◽  
José Granado ◽  
Ernst Freydl ◽  
Urs Wäspi ◽  
Robert Dudler
Keyword(s):  
Signal Transduction ◽  
Pseudomonas Syringae ◽  
Kinase Inhibitors ◽  
De Novo ◽  
Signal Transduction Pathway ◽  
Defense Responses ◽  
Protein Kinase Inhibitors ◽  
Transcript Accumulation ◽  
Transcript Levels ◽  
Phosphatase Inhibitors

Inoculation of rice plants (Oryza sativa) with the nonhost pathogen Pseudomonas syringae pv. syringae leads to the activation of defense-related genes and ultimately to induced resistance against the rice blast fungus Pyricularia oryzae. One of the molecular determinants of P. syringae pv. syringae that is recognized by the plant cells and evokes these defense responses is syringolin A, an elicitor that is secreted by the bacteria under appropriate conditions. In order to investigate signal transduction events elicited by syringolin A, the response of cultured rice cells to syringolin A application was analyzed. Cultured rice cells were able to sense syringolin A at concentrations in the nanomolar range as observed by the transient accumulation of Pir7b esterase transcripts. Syringolin A-mediated Pir7b transcript accumulation was inhibited by cycloheximide, indicating that de novo protein synthesis was required. Calyculin and okadaic acid, two protein phosphatase inhibitors, blocked Pir7b gene induction, whereas the serine/threonine protein kinase inhibitors staurosporine and K-252a had no effect on Pir7b transcript levels. Actin transcript levels were essentially not affected by inhibitor treatments over the experimental time span. These results imply that dephosphorylation of a phosphoprotein is an important step in the syringolin A-triggered signal transduction pathway.

scholarly journals Sinorhizobium fredii HH103 Invades Lotus burttii by Crack Entry in a Nod Factor–and Surface Polysaccharide–Dependent Manner

2016 ◽  
Vol 29 (12) ◽  
pp. 925-937 ◽  
Author(s):  
Sebastián Acosta-Jurado ◽  
Dulce-Nombre Rodríguez-Navarro ◽  
Yasuyuki Kawaharada ◽  
Juan Fernández Perea ◽  
Antonio Gil-Serrano ◽  
...  
Keyword(s):  
Root Hairs ◽  
Broad Host Range ◽  
Capsular Polysaccharides ◽  
Dependent Manner ◽  
Nod Factors ◽  
Sinorhizobium Fredii ◽  
Nod Factor ◽  
Mesorhizobium Loti ◽  
Infection Threads ◽  
Surface Polysaccharide

Sinorhizobium fredii HH103-Rifr, a broad host range rhizobial strain, induces nitrogen-fixing nodules in Lotus burttii but ineffective nodules in L. japonicus. Confocal microscopy studies showed that Mesorhizobium loti MAFF303099 and S. fredii HH103-Rifr invade L. burttii roots through infection threads or epidermal cracks, respectively. Infection threads in root hairs were not observed in L. burttii plants inoculated with S. fredii HH103-Rifr. A S. fredii HH103-Rifr nodA mutant failed to nodulate L. burttii, demonstrating that Nod factors are strictly necessary for this crack-entry mode, and a noeL mutant was also severely impaired in L. burttii nodulation, indicating that the presence of fucosyl residues in the Nod factor is symbiotically relevant. However, significant symbiotic impacts due to the absence of methylation or to acetylation of the fucosyl residue were not detected. In contrast S. fredii HH103-Rifr mutants showing lipopolysaccharide alterations had reduced symbiotic capacity, while mutants affected in production of either exopolysaccharides, capsular polysaccharides, or both were not impaired in nodulation. Mutants unable to produce cyclic glucans and purine or pyrimidine auxotrophic mutants formed ineffective nodules with L. burttii. Flagellin-dependent bacterial mobility was not required for crack infection, since HH103-Rifr fla mutants nodulated L. burttii. None of the S. fredii HH103-Rifr surface-polysaccharide mutants gained effective nodulation with L. japonicus.

scholarly journals Differential accumulation of plant defense gene transcripts in a compatible and an incompatible plant-pathogen interaction.

1986 ◽  
Vol 6 (5) ◽  
pp. 1615-1623 ◽  
Author(s):  
J N Bell ◽  
T B Ryder ◽  
V P Wingate ◽  
J A Bailey ◽  
C J Lamb
Keyword(s):  
Plant Defense ◽  
Phenylalanine Ammonia Lyase ◽  
Chalcone Synthase ◽  
Defense Responses ◽  
Infected Tissue ◽  
Colletotrichum Lindemuthianum ◽  
Specific Interactions ◽  
Defense Gene ◽  
Sequence Of Events ◽  
Gene Transcripts

Phenylalanine ammonia-lyase and chalcone synthase catalyze the first reaction of phenylpropanoid biosynthesis and the first reaction of a branch pathway specific for flavonoid-isoflavonoid biosynthesis, respectively. These enzymes are key control elements in the synthesis of kievitone, phaseollin, and related isoflavonoid-derived phytoalexins. RNA blot hybridization with 32P-labeled cDNA sequences was used to demonstrate marked accumulation of phenylalanine ammonia-lyase and chalcone synthase mRNAs in excision-wounded hypocotyls of Phaseolus vulgaris L. (dwarf French bean) and during race-cultivar-specific interactions between hypocotyls of P. vulgaris and the partially biotrophic fungus Colletotrichum lindemuthianum, the causal agent of anthracnose. In an incompatible interaction (host resistant), early concomitant accumulation of phenylalanine ammonia-lyase and chalcone synthase mRNAs, localized mainly but not entirely in tissue adjacent to the site of infection, was observed prior to the onset of phytoalexin accumulation and expression of localized, hypersensitive resistance. In contrast, in a compatible interaction (host susceptible) there was no early accumulation of these transcripts; instead, there was a delayed widespread response associated with phytoalexin accumulation during attempted lesion limitation. Two-dimensional gel electrophoresis of [35S]methionine-labeled polypeptides synthesized in vitro by translation of isolated polysomal RNA demonstrated stimulation of the synthesis of characteristic sets of phenylalanine ammonia-lyase and chalcone synthase isopolypeptides in directly infected tissue and distant, hitherto uninfected tissue in both compatible and incompatible interactions. Our data show that specific accumulation of plant defense gene transcripts is a key early component in the sequence of events leading to expression of defense responses in wounded tissue and in infected tissue during race-cultivar-specific interactions and that an elicitation signal is transmitted intercellularly in response to infection.

scholarly journals Nod Factors Alter the Microtubule Cytoskeleton in Medicago truncatula Root Hairs to Allow Root Hair Reorientation

2005 ◽  
Vol 18 (11) ◽  
pp. 1195-1204 ◽  
Author(s):  
Björn J. Sieberer ◽  
Antonius C. J. Timmers ◽  
Anne Mie C. Emons
Keyword(s):  
Medicago Truncatula ◽  
Root Hair ◽  
Tip Growth ◽  
Root Hairs ◽  
High Density ◽  
Nod Factors ◽  
Microtubule Cytoskeleton ◽  
Nod Factor ◽  
Set Up ◽  
Drug Studies

The microtubule (MT) cytoskeleton is an important part of the tip-growth machinery in legume root hairs. Here we report the effect of Nod factor (NF) on MTs in root hairs of Medicago truncatula. In tip-growing hairs, the ones that typically curl around rhizobia, NF caused a subtle shortening of the endoplasmic MT array, which recovered within 10 min, whereas cortical MTs were not visibly affected. In growth-arresting root hairs, endoplasmic MTs disappeared shortly after NF application, but reformed within 20 min, whereas cortical MTs remained present in a high density. After NF treatment, growth-arresting hairs were swelling at their tips, after which a new outgrowth formed that deviated with a certain angle from the former growth axis. MT depolymerization with oryzalin caused a growth deviation similar to the NF; whereas, combined with NF, oryzalin increased and the MT-stabilizing drug taxol suppressed NF-induced growth deviation. The NF-induced disappearance of the endoplasmic MTs correlated with a loss of polar cytoarchitecture and straight growth directionality, whereas the reappearance of endoplasmic MTs correlated with the new set up of polar cytoarchitecture. Drug studies showed that MTs are involved in determining root hair elongation in a new direction after NF treatment.

scholarly journals Rhizobium sp. Strain NGR234 and R. fredii USDA257 Share Exceptionally Broad, Nested Host Ranges

1999 ◽  
Vol 12 (4) ◽  
pp. 293-318 ◽  
Author(s):  
Steven G. Pueppke ◽  
William J. Broughton
Keyword(s):  
Glycine Max ◽  
Papua New Guinea ◽  
Broad Host Range ◽  
Nod Factors ◽  
Chamaecrista Fasciculata ◽  
Nod Factor ◽  
Australian Species ◽  
Apios Americana ◽  
Preferred Hosts ◽  
Rhizobium Sp

Genetically, Rhizobium sp. strain NGR234 and R. fredii USDA257 are closely related. Small differences in their nodulation genes result in NGR234 secreting larger amounts of more diverse lipo-oligosaccharidic Nod factors than USDA257. What effects these differences have on nodulation were analyzed by inoculating 452 species of legumes, representing all three subfamilies of the Leguminosae, as well as the nonlegume Parasponia andersonii, with both strains. The two bacteria nodulated P. andersonii, induced ineffective outgrowths on Delonix regia, and nodulated Chamaecrista fasciculata, a member of the only nodulating genus of the Caesalpinieae tested. Both strains nodulated a range of mimosoid legumes, especially the Australian species of Acacia, and the tribe Ingeae. Highest compatibilities were found with the papilionoid tribes Phaseoleae and Desmodieae. On Vigna spp. (Phaseoleae), both bacteria formed more effective symbioses than rhizobia of the “cowpea” (V. unguiculata) miscellany. USDA257 nodulated an exact subset (79 genera) of the NGR234 hosts (112 genera). If only one of the bacteria formed effective, nitrogen-fixing nodules it was usually NGR234. The only exceptions were with Apios americana, Glycine max, and G. soja. Few correlations can be drawn between Nod-factor substituents and the ability to nodulate specific legumes. Relationships between the ability to nodulate and the origin of the host were not apparent. As both P. andersonii and NGR234 originate from Indonesia/Malaysia/Papua New Guinea, and NGR234's preferred hosts (Desmodiinae/ Phaseoleae) are largely Asian, we suggest that broad host range originated in Southeast Asia and spread outward.

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