Root Hair Deformation of Symbiosis-Deficient Mutants of Lotus japonicus by Application of Nod Factor from Mesorhizobium loti

SUMMARYPost-translational modification of receptor proteins is involved in activation and de-activation of signaling systems in plants. Both ubiquitination and deubiquitination have been implicated in plant interactions with pathogens and symbionts. Here we presentLjPUB13, a PUB-ARMADILLO repeat E3 ligase that specifically ubiquitinates the kinase domain of the Nod Factor receptor NFR5 and has a direct role in nodule organogenesis events inLotus japonicus. Phenotypic analyses of three LORE1 retroelement insertion plant lines revealed thatpub13plants display delayed and reduced nodulation capacity and retarded growth.LjPUB13expression is spatially regulated during symbiosis withMesorhizobium loti, with increased levels in young developing nodules. Thus,LjPUB13 is an E3 ligase with a positive regulatory role during the initial stages of nodulation inL. japonicus.

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

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.1997.10.2.215 ◽

1997 ◽

Vol 10 (2) ◽

pp. 215-220 ◽

Cited By ~ 52

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.

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

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2003.16.10.884 ◽

2003 ◽

Vol 16 (10) ◽

pp. 884-892 ◽

Cited By ~ 15

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.

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Differential Effects of Combined N Sources on Early Steps of the Nod Factor–Dependent Transduction Pathway in Lotus japonicus

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-20-8-0994 ◽

2007 ◽

Vol 20 (8) ◽

pp. 994-1003 ◽

Cited By ~ 50

Author(s):

Ani Barbulova ◽

Alessandra Rogato ◽

Enrica D'Apuzzo ◽

Selim Omrane ◽

Maurizio Chiurazzi

Keyword(s):

Root Nodules ◽

Lotus Japonicus ◽

Small Scale ◽

Nodule Formation ◽

Inhibitory Effects ◽

Nod Factor ◽

Mesorhizobium Loti ◽

N Sources ◽

N Starvation ◽

And Function

The development of nitrogen-fixing nodules in legumes is induced by perception of lipochitin-oligosaccharide signals secreted by a bacterial symbiont. Nitrogen (N) starvation is a prerequisite for the formation, development, and function of root nodules, and high levels of combined N in the form of nitrate or ammonium can completely abolish nodule formation. We distinguished between nitrate and ammonium inhibitory effects by identifying when and where these combined N sources interfere with the Nod-factor-induced pathway. Furthermore, we present a small-scale analysis of the expression profile, under different N conditions, of recently identified genes involved in the Nod-factor-induced pathway. In the presence of high levels of nitrate or ammonium, the NIN gene fails to be induced 24 h after the addition of Nod factor compared with plants grown under N-free conditions. This induction is restored in the hypernodulating nitrate-tolerant har1-3 mutant only in the presence of 10 and 20 mM KNO3. These results were confirmed in Lotus plants inoculated with Mesorhizobium loti. NIN plays a key role in the nodule organogenesis program and its downregulation may represent a crucial event in the nitrate-dependent pathway leading to the inhibition of nodule organogenesis.

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The Small GTPase ROP10 of Medicago truncatula Is Required for Both Tip Growth of Root Hairs and Nod Factor-Induced Root Hair Deformation

The Plant Cell ◽

10.1105/tpc.114.135210 ◽

2015 ◽

Vol 27 (3) ◽

pp. 806-822 ◽

Cited By ~ 22

Author(s):

Ming-Juan Lei ◽

Qi Wang ◽

Xiaolin Li ◽

Aimin Chen ◽

Li Luo ◽

...

Keyword(s):

Medicago Truncatula ◽

Root Hair ◽

Tip Growth ◽

Root Hairs ◽

Small Gtpase ◽

Nod Factor ◽

Root Hair Deformation

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Responses of a Model Legume Lotus japonicus to Lipochitin Oligosaccharide Nodulation Factors Purified from Mesorhizobium loti JRL501

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2001.14.7.848 ◽

2001 ◽

Vol 14 (7) ◽

pp. 848-856 ◽

Cited By ~ 52

Author(s):

Shinobu Niwa ◽

Masayoshi Kawaguchi ◽

Haruko Imaizumi-Anraku ◽

Svetlana A. Chechetka ◽

Masumi Ishizaka ◽

...

Keyword(s):

High Performance ◽

Molecular Genetic ◽

Lotus Japonicus ◽

Cytoplasmic Bridge ◽

Cortical Cells ◽

Model Legume ◽

Mesorhizobium Loti ◽

Root Hair Deformation ◽

Early Nodulin ◽

Microbe Interactions

Lotus japonicus has been proposed as a model legume for molecular genetic studies of symbiotic plant-microbe interactions leading to the fixation of atmospheric nitrogen. Lipochitin oligosaccharides (LCOs), or Nod factors, were isolated from the culture of Mesorhizobium loti strain JRL501 (MAFF303099), an efficient microsymbiont of L. japonicus B-129 cv. Gifu. High-performance liquid chromatography and mass spectrometric analyses allowed us to identify at least five different structures of LCOs that were produced by JRL501. The major component was NodMl-V(C18:1, Me, Cb, AcFuc), an N-acetyl-glucosamine pentamer in which the nonreducing residue is N-acylated with a C18:1 acyl moiety, N-methylated, and carries a carbamoyl group and the reducing N-acetyl-glucosamine residue is substituted with 4-O-acetyl-fucose. Additional novel LCO structures bearing fucose instead of acetyl-fucose at the reducing end were identified. Mixtures of these LCOs could elicit abundant root hair deformation on L. japonicus roots at a concentration of 10-7 to 10-9 M. Spot inoculation of a few nanograms of LCOs on L. japonicus roots induced the formation of nodule primordia in which the early nodulin genes, ENOD40 and ENOD2, were expressed in a tissue-specific manner. We also observed the formation of a cytoplasmic bridge (preinfection thread) in the swollen outermost cortical cells. This is the first description of cytoplasmic bridge formation by purified LCOs alone in a legume-forming determinate nodules.

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