Helicoidal microfibril deposition in a tip-growing cell and microtubule alignment during tip morphogenesis: a dry-cleaving and freeze-substitution study

1989 ◽  
Vol 67 (8) ◽  
pp. 2401-2408 ◽  
Author(s):  
Anne Mie C. Emons
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Root Hair ◽  
Root Hairs ◽  
Freeze Substitution ◽  
Axial Direction ◽  
Microfibril Orientation ◽  
Growing Cell ◽  
Equisetum Hyemale ◽  
Dry Cleaving

Cell wall microfibril alignment in the tubular portion of Equisetum hyemale root hairs is helicoidal. Lamellae of helicoidal texture are deposited from tip to base; thus, different microfibril orientations are aligned with the plasma membrane successively. Zones with constant mean microfibril orientation are about 300 μm long. In any such zone of dry-cleaned, shadowed preparations, the frequency of microfibrils at the proximal end is 5 to 7 microfibrils per micrometre, which decreases to 0 at the distal end. The orientation of microfibrils of the underlying lamella, the microfibril frequency of which is 5 to 7/μm throughout, is the same as the microfibril orientation of the neighbouring distal lamella. Microfibrils of the cell wall are randomly oriented in the hair dome. Microtubule alignment in these root hairs was examined by means of freeze substitution. In the extreme tip of the root hair, microtubules run parallel to the plasma membrane and transverse to the long axis of the hair; the hemisphere of the hair contains randomly oriented microtubules. From extreme tip to base of the hair dome, microtubules become more and more axially aligned, and remain axially oriented in the hair tube. Further down the hair, where microfibril alignment is transverse and microfibrils are actively being deposited, microtubules still run in the axial direction. The observations emphasize the involvement of microtubles in root hair tip morphogenesis, but not in determining the alignment of the microfibrils in the hair tube.

scholarly journals The SYP123-VAMP727 SNARE complex is involved in the delivery of inner cell wall components to the root hair shank in Arabidopsis

2020 ◽  
Author(s):  
Tomoko Hirano ◽  
Kazuo Ebine ◽  
Takashi Ueda ◽  
Takumi Higaki ◽  
Takahiro Nakayama ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Root Hair ◽  
Cortical Microtubule ◽  
Root Hairs ◽  
Snare Complex ◽  
Cell Wall Components ◽  
Root Hair Cell ◽  
Wall Stiffness ◽  
Wall Components

AbstractA root hair is a long tubular protrusion from a root hair cell established via tip growth, which is accomplished by the polarized deposition of membranous and cell wall components at the root hair apex accompanied by simultaneous hardening of the shank. The polarized secretion of materials to the root hair apex is well investigated; however, little is known about the deposition of inner cell wall materials at the root hair shank. We have previously reported that phosphatidylinositol-3,5-bisphosphate (PtdIns(3,5)P2)/ROP10 signaling is required for the regulation of cortical microtubule construction and the deposition of inner cell wall components at the root hair shank during hardening. To unravel the alternate secretion mechanism for delivery of the inner cell wall components to root hair shank, here, we demonstrate that root hair-specific Qa-SNARE, SYP123, localizes to the subapical zone and shank of elongating root hairs in Arabidopsis. SYP123-mediated root hair elongation was inhibited by the FAB1 inhibitor YM201636, and inhibition of PtdIns(3,5)P2 production impaired the plasma membrane localization of SYP123. We also showed that SYP123 forms a SNARE complex with VAMP727 on the plasma membrane, and syp123 and vamp727 mutants exhibited lower cell wall stiffness in the root hair shank because of impaired deposition of inner cell wall components. These results indicate that SYP123/VAMP727-mediated secretion is involved in the transport of inner cell wall components for hardening of the root hair shank.

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.

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.

scholarly journals AtRBOHC/RHD2 vesicular delivery to the apical plasma membrane domain during root hair development

2021 ◽  
Author(s):  
Lenka Kuběnová ◽  
Michaela Tichá ◽  
Jozef Šamaj ◽  
Miroslav Ovečka
Keyword(s):  
Plasma Membrane ◽  
Quantitative Analysis ◽  
Root Hair ◽  
Tip Growth ◽  
Root Hairs ◽  
Apical Plasma Membrane ◽  
Loss Of Function ◽  
Short Root ◽  
Early Endosomes ◽  
Root Hair Initiation

AbstractArabidopsis root hairs develop as long tubular extensions from the rootward pole of trichoblasts and exert polarized tip growth. The establishment and maintenance of root hair polarity is a complex process involving the local apical production of reactive oxygen species (ROS) generated by NADPH oxidase RESPIRATORY BURST OXIDASE HOMOLOG PROTEIN C/ROOT HAIR DEFECTIVE 2 (AtRBOHC/RHD2). It has been shown that loss-of-function rhd2 mutants have short root hairs that are unable to elongate by tip growth, and this phenotype was fully complemented by GFP-RHD2 expressed under the RHD2 promoter. However, the spatiotemporal mechanism of AtRBOHC/RHD2 subcellular redistribution and delivery to the plasma membrane (PM) during root hair initiation and tip growth are still unclear. Here, we used advanced microscopy for detailed qualitative and quantitative analysis of vesicular compartments containing GFP-RHD2 and characterization of their movements in developing bulges and growing root hairs. These compartments, identified by an independent marker such as the trans-Golgi network (TGN), deliver GFP-RHD2 to the apical PM domain, the extent of which correlates with the stage of root hair formation. Movements of TGN/early endosomes, but not late endosomes, were affected in the bulging domains of the rhd2-1 mutant. Finally, we reveal that accumulation in the growing tip, docking, and incorporation of TGN compartments containing GFP-RHD2 to the apical PM of root hairs requires structural sterols. These results help clarify the mechanism of polarized AtRBOHC/RHD2 targeting, maintenance, and recycling at the apical PM domain, coordinated with different developmental stages of root hair initiation and growth.One-sentence summaryAdvanced microscopy and quantitative analysis of vesicular TGN compartments revealed that delivering GFP-RHD2 to the apical plasma membrane domains of developing bulges and growing root hairs requires structural sterols.

Cell wall texture in root hairs of the genus Equisetum

1986 ◽  
Vol 64 (10) ◽  
pp. 2201-2206 ◽  
Author(s):  
Anne Mie C. Emons
Keyword(s):  
Cell Wall ◽  
Root Hair ◽  
Root Hairs ◽  
Wall Layer ◽  
Cell Wall Layer ◽  
Additional Layer ◽  
Cell Wall Texture ◽  
Helicoidal Texture

Based on cell wall texture of root hairs, two groups can be distinguished within the 10 species of Equisetum listed in Flora Europaea. This distinction coincides with the division of the genus Equisetum into two subgenera: Equisetum (horsetails) and Hippochaete (scouring rushes). All species of the subgenus Equisetum have a helicoidal cell wall texture in young growing root hairs as well as in full-grown hairs. All species of the subgenus Hippochaete deposit an additional inner cell wall layer against this helicoidal layer when elongation has stopped. The microfibrils in this additional layer do not form a helicoidal texture, but are helically arranged, forming a Z-helix. The presence of a helical layer in full-grown hairs is not a prerequisite for growth in soil, but an exclusively helicoidal root hair wall texture might be favourable for life in water. The wall texture is not influenced by the consistency of the substratum.

Root hair cell walls: filling in the frameworkThis review is one of a selection of papers published in the Special Issue on Plant Cell Biology.

2006 ◽  
Vol 84 (4) ◽  
pp. 613-621 ◽  
Author(s):  
M.E. Galway
Keyword(s):  
Cell Wall ◽  
Hair Cell ◽  
Plant Cell ◽  
Root Hair ◽  
Cell Walls ◽  
Cell Biology ◽  
High Speed ◽  
Root Hairs ◽  
Experimental System ◽  
Plant Cell Walls

Rapid progress is being made in determining the composition, synthesis, and mechanical properties of plant cell walls. Although tip-growing root hairs provide an excellent example of high-speed cell wall assembly, they have been relatively neglected by researchers interested in cell walls and those interested in tip growth. This review aims to present the root hair as an experimental system for future cell wall studies by assembling recent discoveries about the walls onto the existing framework based on older information. Most recent data come from arabidopsis ( Arabidopsis thaliana (L.) Heynh) and model legumes. Evidence supporting the turgor-mediated expansion of hair cell walls is considered, along with a survey of three components needed for cell wall expansion without rupture: cellulose (the role of CesA cellulose synthases is also addressed), Csld3, a cellulose synthase-like protein, and Lrx1, a cell wall protein. Further clues about hair cell wall composition have been obtained from gene expression studies and the use of monoclonal antibodies. Finally, there is a review of the experimental evidence that (i) hairs near the hypocotyl differ developmentally and structurally from other hairs and (ii) biosynthesis of wall components in hairs may differ significantly from the epidermal cells that they grew from. All of these recent advances suggest that root hairs could provide valuable data to augment models of plant cell walls based on more conventional cell types.

scholarly journals From signal to form: aspects of the cytoskeleton-plasma membrane—cell wall continuuum in root hair tips

1997 ◽  
Vol 48 (11) ◽  
pp. 1881-1896 ◽  
Author(s):  
Deborah D. Miller ◽  
Norbert C.A. de Ruijter ◽  
Anne Mie C. Emons
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Root Hair ◽  
Membrane Cell

scholarly journals LRR-extensins of vegetative tissues are a functionally conserved family of RALF1 receptors interacting with the receptor kinase FERONIA

2019 ◽  
Author(s):  
Aline Herger ◽  
Shibu Gupta ◽  
Gabor Kadler ◽  
Christina Maria Franck ◽  
Aurélien Boisson-Dernier ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Plasma Membrane ◽  
Cell Growth ◽  
Mechanical Stability ◽  
Root Hairs ◽  
Cell Wall Integrity ◽  
Receptor Kinase ◽  
Growth Processes ◽  
Evolutionary Diversification

AbstractPlant cell growth requires the coordinated expansion of the protoplast and the cell wall that confers mechanical stability to the cell. An elaborate system of cell wall integrity sensors monitors cell wall structures and conveys information on cell wall composition and growth factors to the cell. LRR-extensins (LRXs) are cell wall-attached extracellular regulators of cell wall formation and high-affinity binding sites for RALF (rapid alkalinization factor) peptide hormones that trigger diverse physiological processes related to cell growth. RALF peptides are also perceived by receptors at the plasma membrane and LRX4 of Arabidopsis thaliana has been shown to also interact with one of these receptors, FERONIA (FER). Here, we demonstrate that several LRXs, including the main LRX protein of root hairs, LRX1, interact with FER and RALF1 to coordinate growth processes. Membrane association of LRXs correlate with binding to FER, indicating that LRXs represent a physical link between intra- and extracellular compartments via interaction with membrane-localized proteins. Finally, despite evolutionary diversification of the LRR domains of various LRX proteins, many of them are functionally still overlapping, indicative of LRX proteins being central players in regulatory processes that are conserved in very different cell types.Author SummaryCell growth in plants requires the coordinated enlargement of the cell and the surrounding cell wall, which is ascertained by an elaborate system of cell wall integrity sensors, proteins involved in the exchange of information between the cell and the cell wall. In Arabidopsis thaliana, LRR-extensins (LRXs) are localized in the cell wall and are binding RALF peptides, hormones that regulate cell growth-related processes. LRX4 also binds the plasma membrane-localized receptor kinase FERONIA (FER), establishing a link between the cell and the cell wall. It is not clear, however, whether the different LRXs of Arabidopsis have similar functions and how they interact with their binding partners. Here, we demonstrate that interaction with FER and RALFs requires the LRR domain of LRXs and several but not all LRXs can bind these proteins. This explains the observation that mutations in several of the LRXs induce phenotypes comparable to a fer mutant, establishing that LRX-FER interaction is important for proper cell growth. Some LRXs, however, appear to influence cell growth processes in different ways, which remain to be identified.

Non-enzymatic access to the plasma membrane of Medicago root hairs by laser microsurgery

1993 ◽  
Vol 105 (1) ◽  
pp. 263-268
Author(s):  
A. Kurkdjian ◽  
G. Leitz ◽  
P. Manigault ◽  
A. Harim ◽  
K.O. Greulich
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Membrane Integrity ◽  
Root Hairs ◽  
Enzyme Treatment ◽  
Direct Access ◽  
Laser Technique ◽  
Laser Microsurgery ◽  
Patch Clamp Technique ◽  
Electrophysiological Studies

Using UV laser microsurgery, the cell walls of root hairs from Medicago sativa (alfalfa) were perforated under plasmolysing conditions, giving direct access to the plasma membrane without enzyme treatment. The opening in the cell wall of a few micrometre in diameter results in immediate movement of the protoplasm and partial or complete extrusion of the cell contents. The movement of the protoplasm is retarded by increases in calcium concentration. The calcium-dependency of the movement of the protoplasm allows us to obtain preferentially the extrusion of protoplasm, or to gain access to a small area of plasma membrane in situ. The complete protoplasm can be expelled, to form a protoplast. Fluorescein diacetate staining indicated esterase activity and membrane integrity of the protoplasts. Microscopic examination revealed organelle movement and the presence of a nucleus. The plasma membrane was free from cell wall fragments, as shown by Tinopal staining. Conditions for obtaining plasmolysis without disturbing the physiology of the root hairs too much were achieved by slow, stepwise and reversible plasmolysis. Cytoplasmic streaming in root hairs was maintained during plasmolysis and laser microperforation. This laser technique should be suitable for the performance of electrophysiological studies using the patch-clamp technique on plasma membrane from non-enzyme-treated cells.

scholarly journals Nanodomain-mediated lateral sorting drives polarization of the small GTPase ROP2 in the plasma membrane of root hair cells

2021 ◽  
Author(s):  
Vanessa Aphaia Fiona Fuchs ◽  
Philipp Denninger ◽  
Milan Župunski ◽  
Yvon Jaillais ◽  
Ulrike Engel ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Single Molecule ◽  
Root Hair ◽  
Root Hairs ◽  
Small Gtpases ◽  
Small Gtpase ◽  
Cellular Growth ◽  
Epifluorescence Microscopy ◽  
Anionic Phospholipids ◽  
Downstream Effectors

Formation of root hairs involves the targeted recruitment of the cellular growth machinery to the root hair initiation domain (RHID), a specialized site at the plasma membrane (PM) of trichoblast cells. Early determinants in RHID establishment are small GTPases of the Rho-of-plants (ROP) protein family, which are required for polarization of downstream effectors, membrane modification and targeted secretion during tip growth. It remains, however, not fully understood how ROP GTPases themselves are polarized. To investigate the mechanism underlying ROP2 recruitment, we employed Variable Angle Epifluorescence Microscopy (VAEM) and exploited mCitrine fluorophore blinking for single molecule localization, particle tracking and super-resolved imaging of the trichoblast plasma membrane. We observed the association of mCit-ROP2 within distinct membrane nanodomains, whose polar occurrence at the RHID was dependent on the presence of the RopGEF GEF3, and found a gradual, localized decrease of mCit-ROP2 protein mobility that preceded polarization. We provide evidence for a step-wise model of ROP2 polarization that involves (i) an initial non-polar recruitment to the plasma membrane via interactions with anionic phospholipids, (ii) ROP2 assembly into membrane nanodomains independent of nucleotide-binding state and, sub-sequently, (iii) lateral sorting into the RHID, driven by GEF3-mediated localized reduction of ROP2 mobility.

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