Plasma-membrane rosettes in root hairs of Equisetum hyemale

Planta ◽  
1985 ◽  
Vol 163 (3) ◽  
pp. 350-359 ◽  
Author(s):  
Anne Mie C. Emons
Keyword(s):  
Plasma Membrane ◽  
Root Hairs ◽  
Equisetum Hyemale

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.

Microtubules in root hairs

1985 ◽  
Vol 76 (1) ◽  
pp. 303-320 ◽  
Author(s):  
J.A. Traas ◽  
P. Braat ◽  
A.M. Emons ◽  
H. Meekes ◽  
J. Derksen
Keyword(s):  
Raphanus Sativus ◽  
Allium Sativum ◽  
Root Hairs ◽  
Urtica Dioica ◽  
Lepidium Sativum ◽  
Cortical Microtubules ◽  
Cell Morphogenesis ◽  
Equisetum Hyemale ◽  
Ceratopteris Thalictroides ◽  
Cell Wall Deposition

The microtubules of root hairs of Raphanus sativus, Lepidium sativum, Equisetum hyemale, Limnobium stoloniferum, Ceratopteris thalictroides, Allium sativum and Urtica dioica were investigated using immunofluorescence and electron microscopy. Arrays of cortical microtubules were observed in all hairs. The microtubules in the hairs show net axial orientations, but in Allium and Urtica helical microtubule patterns are also present. Numerical parameters of microtubules in Raphanus, Equisetum and Limnobium were determined from dry-cleave preparations. The results are discussed with respect to cell wall deposition and cell morphogenesis.

scholarly journals A repertoire of cationic and anionic conductances at the plasma membrane of Medicago truncatula root hairs

2019 ◽  
Vol 98 (3) ◽  
pp. 418-433 ◽  
Author(s):  
Limin Wang ◽  
Man‐Yuan Guo ◽  
Jean‐Baptiste Thibaud ◽  
Anne‐Aliénor Véry ◽  
Hervé Sentenac
Keyword(s):  
Plasma Membrane ◽  
Medicago Truncatula ◽  
Root Hairs

Recycling domains in plant cell morphogenesis: small GTPase effectors, plasma membrane signalling and the exocyst

2010 ◽  
Vol 38 (2) ◽  
pp. 723-728 ◽  
Author(s):  
Viktor Žárský ◽  
Martin Potocký
Keyword(s):  
Plasma Membrane ◽  
Plant Cell ◽  
Secretory Pathway ◽  
Root Hairs ◽  
Small Gtpases ◽  
Small Gtpase ◽  
Cell Cortex ◽  
Membrane Phospholipids ◽  
Recycling Endosome ◽  
Regulatory Module

The Rho/Rop small GTPase regulatory module is central for initiating exocytotically ACDs (active cortical domains) in plant cell cortex, and a growing array of Rop regulators and effectors are being discovered in plants. Structural membrane phospholipids are important constituents of cells as well as signals, and phospholipid-modifying enzymes are well known effectors of small GTPases. We have shown that PLDs (phospholipases D) and their product, PA (phosphatidic acid), belong to the regulators of the secretory pathway in plants. We have also shown that specific NOXs (NADPH oxidases) producing ROS (reactive oxygen species) are involved in cell growth as exemplified by pollen tubes and root hairs. Most plant cells exhibit several distinct plasma membrane domains (ACDs), established and maintained by endocytosis/exocytosis-driven membrane protein recycling. We proposed recently the concept of a ‘recycling domain’ (RD), uniting the ACD and the connected endosomal recycling compartment (endosome), as a dynamic spatiotemporal entity. We have described a putative GTPase–effector complex exocyst involved in exocytic vesicle tethering in plants. Owing to the multiplicity of its Exo70 subunits, this complex, along with many RabA GTPases (putative recycling endosome organizers), may belong to core regulators of RD organization in plants.

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.

scholarly journals Roles of plasma membrane proton ATPases AHA2 and AHA7 in normal growth of roots and root hairs inArabidopsis thaliana

2018 ◽  
Vol 166 (3) ◽  
pp. 848-861 ◽  
Author(s):  
Robert D. Hoffmann ◽  
Lene I. Olsen ◽  
Chukwuebuka V. Ezike ◽  
Jesper T. Pedersen ◽  
Raffaele Manstretta ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Root Hairs ◽  
Normal Growth

scholarly journals Effect of Fusicoccin on the Early Infection Process of Legume Roots by Rhizobium spp

1999 ◽  
Vol 12 (12) ◽  
pp. 1090-1094 ◽  
Author(s):  
Juan Pedro Donaire ◽  
María Pilar Rodríguez-Rosales ◽  
María José Soto ◽  
Juan Sanjuan ◽  
José Olivares
Keyword(s):  
Plasma Membrane ◽  
Root Hairs ◽  
Infection Process ◽  
Calcium Signal ◽  
Ionophore A23187 ◽  
Cytosolic Ph ◽  
Membrane Hyperpolarization ◽  
Nod Factor ◽  
Rhizobium Spp ◽  
External Calcium

Nod factors, the first detectable signals produced by Rhizobium spp., were reported to induce cytosolic pH changes and plasma membrane depolarization in root hairs as specific responses. In this study, it has been found that fusicoccin inhibits nodulation of alfalfa roots. This inhibition was only observed when fusicoccin was applied in the earlier steps of the bacteria-plant interaction. The observed effect is similar to that caused by the undissociated permeant acetic acid, which decreases the cytoplasmic pH and, like fusicoccin, significantly stimulates net H+ efflux. These results suggest that the fusicoccin-induced plasma membrane H+-ATPase activity and membrane hyperpolarization could be responsible for the nodulation inhibition observed. Moreover, it was found that nodulation was inhibited by removing external calcium with EGTA. When fusicoccin is present, a lower concentration of EGTA is necessary to inhibit nodulation. Furthermore, the addition of Ca2+ ionophore A23187 was found to inhibit H+ efflux by roots. These observations support the idea that the Nod factor-triggered calcium signal modulates the activity of the proton pump.

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.

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