scholarly journals The Medicago truncatula DREPP protein triggers microtubule fragmentation in membrane nanodomains during symbiotic infections

2019 ◽  
Author(s):  
Chao Su ◽  
Marie-Luise Klein ◽  
Casandra Hernández-Reyes ◽  
Morgane Batzenschlager ◽  
Franck Anicet Ditengou ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Root Hair ◽  
Root Hairs ◽  
Dependent Manner ◽  
Partial Loss ◽  
Transgenic Roots ◽  
Symbiotic Associations ◽  
Cell Colonization ◽  
Specific Membrane ◽  
Initial Root

AbstractThe initiation of intracellular host cell colonization by symbiotic rhizobia in Medicago truncatula requires repolarization of root hairs, which includes the re-arrangement of cytoskeletal filaments. The molecular players governing microtubule (MT) re-organization during infection remain to be discovered. Here, we identified the M. truncatula DREPP protein and investigated its functions during rhizobial infections. We show that rhizobial colonization of drepp mutant roots as well as transgenic roots over-expressing DREPP is impaired. DREPP re-localizes into symbiosis-specific membrane nanodomains in a stimulus-dependent manner. This subcellular segregation coincides with DREPP-dependent MT fragmentation and a partial loss of the ability to re-organize the MT cytoskeleton in response to rhizobia, which might relay on an interaction between DREPP and MT organizing protein SPIRAL2 (SPR2). Taken together, our results reveal that establishment of symbiotic associations in M. truncatula require DREPP in order to regulate MT reorganization during initial root hair responses to rhizobia.

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

2015 ◽  
Vol 27 (3) ◽  
pp. 806-822 ◽  
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

scholarly journals The karrikin signaling regulator SMAX1 controlsLotus japonicusroot and root hair development by suppressing ethylene biosynthesis

2020 ◽  
Vol 117 (35) ◽  
pp. 21757-21765 ◽  
Author(s):  
Samy Carbonnel ◽  
Debatosh Das ◽  
Kartikye Varshney ◽  
Markus C. Kolodziej ◽  
José A. Villaécija-Aguilar ◽  
...  
Keyword(s):  
Root Hair ◽  
Lotus Japonicus ◽  
Root Hairs ◽  
Acc Synthase ◽  
Ethylene Biosynthesis ◽  
Dependent Manner ◽  
Ethylene Signaling ◽  
Root Hair Development ◽  
Hair Development ◽  
Developmental Responses

An evolutionarily ancient plant hormone receptor complex comprising the α/β-fold hydrolase receptor KARRIKIN INSENSITIVE 2 (KAI2) and the F-box protein MORE AXILLARY GROWTH 2 (MAX2) mediates a range of developmental responses to smoke-derived butenolides called karrikins (KARs) and to yet elusive endogenous KAI2 ligands (KLs). Degradation of SUPPRESSOR OF MAX2 1 (SMAX1) after ligand perception is considered to be a key step in KAR/KL signaling. However, molecular events which regulate plant development downstream of SMAX1 removal have not been identified. Here we show thatLotus japonicusSMAX1 is specifically degraded in the presence of KAI2 and MAX2 and plays an important role in regulating root and root hair development.smax1mutants display very short primary roots and elongated root hairs. Their root transcriptome reveals elevated ethylene responses and expression ofACC Synthase 7(ACS7), which encodes a rate-limiting enzyme in ethylene biosynthesis.smax1mutants release increased amounts of ethylene and their root phenotype is rescued by treatment with ethylene biosynthesis and signaling inhibitors. KAR treatment inducesACS7expression in a KAI2-dependent manner and root developmental responses to KAR treatment depend on ethylene signaling. Furthermore, inArabidopsis, KAR-induced root hair elongation depends onACS7. Thus, we reveal a connection between KAR/KL and ethylene signaling in which the KAR/KL signaling module (KAI2–MAX2–SMAX1) regulates the biosynthesis of ethylene to fine-tune root and root hair development, which are important for seedling establishment at the beginning of the plant life cycle.

scholarly journals Infection-Specific Activation of the Medicago truncatula Enod11 Early Nodulin Gene Promoter During Actinorhizal Root Nodulation

2010 ◽  
Vol 23 (6) ◽  
pp. 740-747 ◽  
Author(s):  
Sergio Svistoonoff ◽  
Mame-Ourèye Sy ◽  
Nathalie Diagne ◽  
David G. Barker ◽  
Didier Bogusz ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Mycorrhizal Fungi ◽  
Glomus Intraradices ◽  
Root Hairs ◽  
Gene Promoter ◽  
Arbuscular Mycorrhizal ◽  
Gus Expression ◽  
Regulatory Pathways ◽  
Symbiotic Associations ◽  
Gus Reporter

The MtEnod11 gene from Medicago truncatula is widely used as an early infection-related molecular marker for endosymbiotic associations involving both rhizobia and arbuscular mycorrhizal fungi. In this article, heterologous expression of the MtEnod11 promoter has been studied in two actinorhizal trees, Casuarina glauca and Allocasuarina verticillata. Transgenic C. glauca and A. verticillata expressing a ProMtEnod11::β-glucuronidase (gus) fusion were generated and the activation of the transgene investigated in the context of the symbiotic associations with the N-fixing actinomycete Frankia and both endo- and ectomycorrhizal fungi (Glomus intraradices and Pisolithus albus, respectively). ProMtEnod11::gus expression was observed in root hairs, prenodules, and nodules and could be correlated with the infection of plant cells by Frankia spp. However, no activation of the gus reporter gene was detected prior to infection or in response to either rhizobial Nod factors or the wasp venom peptide MAS-7. Equally, ProMtEnod11::gus expression was not elicited during the symbiotic associations with either ecto- or endomycorrhizal fungi. These observations suggest that, although there is a conservation of gene regulatory pathways between legumes and actinorhizal plants in cells accommodating endosymbiotic N-fixing bacteria, the events preceding bacterial infection or related to mycorrhization appear to be less conserved.

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.

SEM and fluorescence imaging of callose deposition in root hair tips and suspension cultures of Streptanthus tortuosus

1990 ◽  
Vol 48 (3) ◽  
pp. 698-699
Author(s):  
K.S. Walters ◽  
R.D. Sjolund ◽  
K.C. Moore
Keyword(s):  
Cell Wall ◽  
Root Hair ◽  
Cultured Cells ◽  
Root Hairs ◽  
Callus Cultures ◽  
Callose Deposition ◽  
Culture Cells ◽  
Wall Structures ◽  
Ultraviolet Illumination ◽  
Callose Formation

Callose, B-1,3-glucan, a component of cell walls, is associated with phloem sieve plates, plasmodesmata, and other cell wall structures that are formed in response to wounding or infection. Callose reacts with aniline blue to form a fluorescent complex that can be recognized in the light microscope with ultraviolet illumination. We have identified callose in cell wall protuberances that are formed spontaneously in suspension-cultured cells of S. tortuosus and in the tips of root hairs formed in sterile callus cultures of S. tortuosus. Callose deposits in root hairs are restricted to root hair tips which appear to be damaged or deformed, while normal root hair tips lack callose deposits. The callose deposits found in suspension culture cells are restricted to regions where unusual outgrowths or protuberances are formed on the cell surfaces, specifically regions that are the sites of new cell wall formation.Callose formation has been shown to be regulated by intracellular calcium levels.

scholarly journals The TOR–Auxin Connection Upstream of Root Hair Growth

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 150 ◽  
Author(s):  
Katarzyna Retzer ◽  
Wolfram Weckwerth
Keyword(s):  
Cell Fate ◽  
Root Hair ◽  
Hair Growth ◽  
Environmental Changes ◽  
Growth Control ◽  
Root Hairs ◽  
Signaling Cascades ◽  
Continuous Growth ◽  
Root Hair Cell ◽  
Root Hair Growth

Plant growth and productivity are orchestrated by a network of signaling cascades involved in balancing responses to perceived environmental changes with resource availability. Vascular plants are divided into the shoot, an aboveground organ where sugar is synthesized, and the underground located root. Continuous growth requires the generation of energy in the form of carbohydrates in the leaves upon photosynthesis and uptake of nutrients and water through root hairs. Root hair outgrowth depends on the overall condition of the plant and its energy level must be high enough to maintain root growth. TARGET OF RAPAMYCIN (TOR)-mediated signaling cascades serve as a hub to evaluate which resources are needed to respond to external stimuli and which are available to maintain proper plant adaptation. Root hair growth further requires appropriate distribution of the phytohormone auxin, which primes root hair cell fate and triggers root hair elongation. Auxin is transported in an active, directed manner by a plasma membrane located carrier. The auxin efflux carrier PIN-FORMED 2 is necessary to transport auxin to root hair cells, followed by subcellular rearrangements involved in root hair outgrowth. This review presents an overview of events upstream and downstream of PIN2 action, which are involved in root hair growth control.

scholarly journals Arabidopsis VILLIN4 is involved in root hair growth through regulating actin organization in a Ca2+-dependent manner

2011 ◽  
Vol 190 (3) ◽  
pp. 667-682 ◽  
Author(s):  
Yi Zhang ◽  
Yingyu Xiao ◽  
Fei Du ◽  
Lijuan Cao ◽  
Huaijian Dong ◽  
...  
Keyword(s):  
Root Hair ◽  
Hair Growth ◽  
Dependent Manner ◽  
Actin Organization ◽  
Root Hair Growth

Cytological and histochemical characteristics of the axenic root surface of Alnus glutinosa

1986 ◽  
Vol 64 (10) ◽  
pp. 2216-2226 ◽  
Author(s):  
Yves Prin ◽  
Mireille Rougier
Keyword(s):  
Cell Wall ◽  
Root Hair ◽  
Root Hairs ◽  
Root Apex ◽  
Alnus Glutinosa ◽  
Root Surface ◽  
Infection Process ◽  
Root Cap ◽  
A Cell ◽  
Histochemical Tests

The aim of the present study was to investigate the Alnus root surface using seedlings grown axenically. This study has focused on root zones where infection by the symbiotic actinomycete Frankia takes place. The zones examined extend from the root cap to the emerging root hair zone. The root cap ensheaths the Alnus root apex and extends over the root surface as a layer of highly flattened cells closely appressed to the root epidermal cell wall. These cells contain phenolic compounds as demonstrated by various histochemical tests. They are externally bordered by a thin cell wall coated by a thin mucilage layer. The root cap is ruptured when underlying epidermal cells elongate, and cell remnants are still found in the emerging root hair zone. Young emerging root hairs are bordered externally by a cell wall covered by a thin mucilage layer which reacts positively to the tests used for the detection of polysaccharides, glycoproteins, and anionic sites. The characteristics of the Alnus root surface and the biological function of mucilage and phenols present at the root surface are discussed in relation to the infection process.

The life history of Plasmodiophora brassicae Woron

1972 ◽  
Vol 180 (1058) ◽  
pp. 103-112 ◽  
Keyword(s):  
Life History ◽  
Root Hair ◽  
Plasmodiophora Brassicae ◽  
Root Hairs ◽  
Secondary Phase ◽  
Tissue Cultures ◽  
Resting Spore ◽  
Resting Spores ◽  
Seedling Roots ◽  
History Of

Resting spore germination and the root hair stages of the life history of Plasmodiophora brassicae were studied in stained preparations of infected Brassica rapa seedling roots. Naked protoplasts, usually possessing two unequal flagella, were released from resting spores through a small circular pore. They penetrated the root hairs of B. rapa and there developed into plasmodia which, after becoming multinucleate, cleaved to form zoosporangia con­taining incipient zoospores. Biflagellate zoospores were released from root hair zoosporangia and fused in pairs, although karyogamy did not occur. The resulting binucleate zoospores infected the cortical dells of B. rapa to form binucleate plasmodia, the earliest stages of the secondary phase of the life history. These findings are discussed in relation to previous studies on the life history of P. brassicae in Brassica plants and in Brassica tissue cultures, and a new complete life history, including nuclear fusion in the secondary plasmodium, is suggested for the organism.

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