scholarly journals Interplay between turgor pressure and plasmodesmata during plant development

2019 ◽  
Author(s):  
Valeria Hernández-Hernández ◽  
Mariana Benítez ◽  
Arezki Boudaoud
Keyword(s):  
Plant Development ◽  
Cell Walls ◽  
Lateral Roots ◽  
Turgor Pressure ◽  
Mechanical Forces ◽  
Root Initiation ◽  
Vascular Differentiation ◽  
Physiological Processes ◽  
Intercellular Movement ◽  
Transition To Flowering

Abstract Plasmodesmata traverse cell walls, generating connections between neighboring cells. They allow intercellular movement of molecules such as transcription factors, hormones, and sugars, and thus create a symplasmic continuity within a tissue. One important factor that determines plasmodesmal permeability is their aperture, which is regulated during developmental and physiological processes. Regulation of aperture has been shown to affect developmental events such as vascular differentiation in the root, initiation of lateral roots, or transition to flowering. Extensive research has unraveled molecular factors involved in the regulation of plasmodesmal permeability. Nevertheless, many plant developmental processes appear to involve feedbacks mediated by mechanical forces, raising the question of whether mechanical forces and plasmodesmal permeability affect each other. Here, we review experimental data on how one of these forces, turgor pressure, and plasmodesmal permeability may mutually influence each other during plant development, and we discuss the questions raised by these data. Addressing such questions will improve our knowledge of how cellular patterns emerge during development, shedding light on the evolution of complex multicellular plants.

Formation of lateral root meristems is a two-stage process

Development ◽  
1995 ◽  
Vol 121 (10) ◽  
pp. 3303-3310 ◽  
Author(s):  
M.J. Laskowski ◽  
M.E. Williams ◽  
H.C. Nusbaum ◽  
I.M. Sussex
Keyword(s):  
Lateral Root ◽  
Lateral Roots ◽  
Initial Period ◽  
Subsequent Stage ◽  
Root Initiation ◽  
Root Meristems ◽  
Lateral Root Initiation ◽  
Cell Layers ◽  
Stage Process ◽  
Pericycle Cells

In both radish and Arabidopsis, lateral root initiation involves a series of rapid divisions in pericycle cells located on the xylem radius of the root. In Arabidopsis, the number of pericycle cells that divide to form a primordium was estimated to be about 11. To determine the stage at which primordia are able to function as root meristems, primordia of different stages were excised and cultured without added hormones. Under these conditions, primordia that consist of 2 cell layers fail to develop while primordia that consist of at least 3–5 cell layers develop as lateral roots. We hypothesize that meristem formation is a two-step process involving an initial period during which a population of rapidly dividing, approximately isodiametric cells that constitutes the primordium is formed, and a subsequent stage during which meristem organization takes place within the primordium.

scholarly journals AT-HOOK MOTIF NUCLEAR LOCALISED PROTEIN 18 as a Novel Modulator of Root System Architecture

2020 ◽  
Author(s):  
Marek Šírl ◽  
Tereza Šnajdrová ◽  
Dolores Gutiérrez-Alanís ◽  
Joseph G. Dubrovsky ◽  
Jean Phillipe Vielle-Calzada ◽  
...  
Keyword(s):  
Root System ◽  
System Architecture ◽  
Lateral Root ◽  
Apical Meristem ◽  
Lateral Roots ◽  
Primary Root ◽  
Root System Architecture ◽  
Root Apical Meristem ◽  
Root Initiation ◽  
Lateral Root Initiation

The AT-HOOK MOTIF NUCLEAR LOCALIZED PROTEIN (AHL) gene family encodes embryophyte-specific nuclear proteins with DNA binding activity. They modulate gene expression and affect various developmental processes in plants. We identify AHL18 (At3G60870) as a developmental modulator of root system architecture and growth. AHL18 regulates the length of the proliferation domain and number of dividing cells in the root apical meristem and thereby, cell production. Both primary root growth and lateral root development respond according to AHL18 transcription level. The ahl18 knock-out plants show reduced root systems due to a shorter primary root and a lower number of lateral roots. This change results from a higher number of arrested and non-developing lateral root primordia (LRP) rather than from decreased initiation. Overexpression of AHL18 results in a more extensive root system, longer primary roots, and increased density of lateral root initiation events. Formation of lateral roots is affected during the initiation of LRP and later development. AHL18 regulate root apical meristem activity, lateral root initiation and emergence, which is in accord with localization of its expression.

VASCULAR DIFFERENTIATION OF STEM CELLS BY MECHANICAL FORCES

2010 ◽  
pp. 247-269 ◽  
Author(s):  
TIMOTHY M. MAUL ◽  
ALEJANDRO NIEPONICE ◽  
DAVID A VORP
Keyword(s):  
Stem Cells ◽  
Mechanical Forces ◽  
Vascular Differentiation

Differential effects of static and cyclic stretching during elastase digestion on the mechanical properties of extracellular matrices

2007 ◽  
Vol 103 (3) ◽  
pp. 803-811 ◽  
Author(s):  
Rajiv Jesudason ◽  
Lauren Black ◽  
Arnab Majumdar ◽  
Phillip Stone ◽  
Bela Suki
Keyword(s):  
Mechanical Properties ◽  
Enzyme Activity ◽  
Failure Stress ◽  
Cyclic Stretch ◽  
Mechanical Forces ◽  
Peak Strain ◽  
Static Stretch ◽  
Cyclic Stretching ◽  
Rate Dependent ◽  
Physiological Processes

Enzyme activity plays an essential role in many physiological processes and diseases such as pulmonary emphysema. While the lung is constantly exposed to cyclic stretching, the effects of stretch on the mechanical properties of the extracellular matrix (ECM) during digestion have not been determined. We measured the mechanical and failure properties of elastin-rich ECM sheets loaded with static or cyclic uniaxial stretch (40% peak strain) during elastase digestion. Quasistatic stress-strain measurements were taken during 30 min of digestion. The incremental stiffness of the sheets decreased exponentially with time during digestion. However, digestion in the presence of static stretch resulted in an accelerated stiffness decrease, with a time constant that was nearly 3× smaller (7.1 min) than during digestion alone (18.4 min). These results were supported by simulations that used a nonlinear spring network model. The reduction in stiffness was larger during static than cyclic stretch, and the latter also depended on the frequency. Stretching at 20 cycles/min decreased stiffness less than stretching at 5 cycles/min, suggesting a rate-dependent coupling between mechanical forces and enzyme activity. Furthermore, pure digestion reduced the failure stress of the sheets from 88 ± 21 kPa in control to 29 ± 15 kPa ( P < 0.05), while static and cyclic stretch resulted in a failure stress of 7 ± 5 kPa ( P < 0.05). We conclude that not only the presence but the dynamic nature of mechanical forces have a significant impact on enzyme activity, hence the deterioration of the functional properties of the ECM during exposure to enzymes.

Measurement of viscoelastic properties of root cell walls affected by low pH in lateral roots of Pisum sativum L.

2001 ◽  
pp. 23-30
Author(s):  
Eiichi Tanimoto ◽  
Shuhei Fujii ◽  
Ryoichi Yamamoto ◽  
Shinobu Inanaga
Keyword(s):  
Pisum Sativum ◽  
Viscoelastic Properties ◽  
Cell Walls ◽  
Lateral Roots ◽  
Low Ph ◽  
Root Cell ◽  
Pisum Sativum L ◽  
Root Cell Walls

scholarly journals Investigation of the Mechanical Properties of Flax Cell Walls during Plant Development: The Relation between Performance and Cell Wall Structure

Fibers ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 6 ◽  
Author(s):  
Camille Goudenhooft ◽  
David Siniscalco ◽  
Olivier Arnould ◽  
Alain Bourmaud ◽  
Olivier Sire ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Plant Development ◽  
Cell Walls ◽  
Cell Wall Structure ◽  
Wall Structure

Lateral root initiation in Marsilea quadrifolia. I. Origin and histogenesis of lateral roots

1991 ◽  
Vol 69 (1) ◽  
pp. 123-135 ◽  
Author(s):  
Bai-Ling Lin ◽  
V. Raghavan
Keyword(s):  
Lateral Root ◽  
Single Cells ◽  
Lateral Roots ◽  
Central Axis ◽  
Root Initiation ◽  
Vascular Connection ◽  
Lateral Root Initiation ◽  
Marsilea Quadrifolia ◽  
Lateral Root Primordium ◽  
Root Primordium

In Marsilea quadrifolia, lateral roots arise from modified single cells of the endodermis located opposite the protoxylem poles within the meristematic region of the parent root. The initial cell divides in four specific planes to establish a fivecelled lateral root primordium, with a tetrahedral apical cell in the centre and the oldest merophytes and the root cap along the sides. The cells of the merophyte divide in a precise pattern to give rise to the cells of the cortex, endodermis, pericycle, and vascular tissues of the emerging lateral root. Although the construction of the parent root is more complicated than that of lateral roots, patterns of cell division and tissue formation are similar in both types of roots, with the various tissues being arranged in similar positions in relation to the central axis. Vascular connection between the lateral root primordium and the parent root is derived from the pericycle cells lying between the former and the protoxylem members of the latter. It is proposed that the central axis of the root is not only a geometric centre, but also a physiological centre which determines the fate of the different cell types. Key words: lateral root initiation, Marsilea quadrifolia, root histogenesis.

scholarly journals Structure and Biomechanics during Xylem Vessel Transdifferentiation in Arabidopsis thaliana

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1715
Author(s):  
Eleftheria Roumeli ◽  
Leah Ginsberg ◽  
Robin McDonald ◽  
Giada Spigolon ◽  
Rodinde Hendrickx ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Cell Walls ◽  
Turgor Pressure ◽  
Plant Cells ◽  
Building Blocks ◽  
Xylem Vessel ◽  
Primary Cell Wall ◽  
Individual Plant ◽  
Vessel Elements

Individual plant cells are the building blocks for all plantae and artificially constructed plant biomaterials, like biocomposites. Secondary cell walls (SCWs) are a key component for mediating mechanical strength and stiffness in both living vascular plants and biocomposite materials. In this paper, we study the structure and biomechanics of cultured plant cells during the cellular developmental stages associated with SCW formation. We use a model culture system that induces transdifferentiation of Arabidopsis thaliana cells to xylem vessel elements, upon treatment with dexamethasone (DEX). We group the transdifferentiation process into three distinct stages, based on morphological observations of the cell walls. The first stage includes cells with only a primary cell wall (PCW), the second covers cells that have formed a SCW, and the third stage includes cells with a ruptured tonoplast and partially or fully degraded PCW. We adopt a multi-scale approach to study the mechanical properties of cells in these three stages. We perform large-scale indentations with a micro-compression system in three different osmotic conditions. Atomic force microscopy (AFM) nanoscale indentations in water allow us to isolate the cell wall response. We propose a spring-based model to deconvolve the competing stiffness contributions from turgor pressure, PCW, SCW and cytoplasm in the stiffness of differentiating cells. Prior to triggering differentiation, cells in hypotonic pressure conditions are significantly stiffer than cells in isotonic or hypertonic conditions, highlighting the dominant role of turgor pressure. Plasmolyzed cells with a SCW reach similar levels of stiffness as cells with maximum turgor pressure. The stiffness of the PCW in all of these conditions is lower than the stiffness of the fully-formed SCW. Our results provide the first experimental characterization of the mechanics of SCW formation at single cell level.

scholarly journals Beta-1,3-Glucanase Activities in Wheat and Relative Species

2016 ◽  
Vol 15 (2) ◽  
pp. 122-132
Author(s):  
Jana Moravčíková ◽  
Denisa Margetínyová ◽  
Zdenka Gálová ◽  
Iwona Žur ◽  
Zuzana Gregorová ◽  
...  
Keyword(s):  
Ploidy Level ◽  
Cell Walls ◽  
Higher Plants ◽  
Hydrolytic Enzymes ◽  
Callose Synthase ◽  
Glucanase Activity ◽  
Callose Deposition ◽  
Qualitative And Quantitative ◽  
Physiological Processes ◽  
Main Component

Abstract The (1,3)-β-D-glucan also referred to as callose is a main component of cell walls of higher plants. Many physiological processes are associated with the changes in callose deposition. Callose is synthesised by the callose synthase complex while its degradation is regulated by the hydrolytic enzymes β-1,3-glucanases. The latter one specifically degrade (1,3)-β-D-glucans. This work is aimed to study β-1,3-glucanase activities in the leaves of plants at two leaf stage in two diploids (Agilops tauschii, Triticum monococcum L.), four tetraploids (Ae. cylindrica, Ae. triuncialis, T. araraticum, T. dicoccum) and two hexaploids (T. aestivum L, T. spelta L.). The leaves were subjected to qualitative and quantitative β-1,3-glucanase activity assays. Our results showed that the total β-1,3-glucanase activities were variable and genotype dependent. No significant correlation between β-1,3-glucanase activities and ploidy level was observed. The gel activity assays revealed a single fraction of ~52 kDa Glu1 that was found in all genotypes. The Glu1 fraction corresponds to a single or two acidic Glu isoforms in dependence on genotype. However, none of the acidic Glu fractions can be assigned as a specific for di-, tetra- or hexaploid genotypes. A single basic GluF isoform was detected and found as present in all genotypes.

scholarly journals A single cell view of the transcriptome during lateral root initiation in Arabidopsis thaliana

2020 ◽  
Author(s):  
Hardik P. Gala ◽  
Amy Lanctot ◽  
Ken Jean-Baptiste ◽  
Sarah Guiziou ◽  
Jonah C. Chu ◽  
...  
Keyword(s):  
Single Cell ◽  
Root Development ◽  
Lateral Root ◽  
Lateral Roots ◽  
Primary Root ◽  
Root Initiation ◽  
Lateral Root Primordia ◽  
Lateral Root Development ◽  
Lateral Root Initiation ◽  
Molecular Events

AbstractRoot architecture is a major determinant of fitness, and is under constant modification in response to favorable and unfavorable environmental stimuli. Beyond impacts on the primary root, the environment can alter the position, spacing, density and length of secondary or lateral roots. Lateral root development is among the best-studied examples of plant organogenesis, yet there are still many unanswered questions about its earliest steps. Among the challenges faced in capturing these first molecular events is the fact that this process occurs in a small number of cells with unpredictable timing. Single-cell sequencing methods afford the opportunity to isolate the specific transcriptional changes occurring in cells undergoing this fate transition. Using this approach, we successfully captured the transcriptomes of initiating lateral root primordia, and discovered many previously unreported upregulated genes associated with this process. We developed a method to selectively repress target gene transcription in the xylem pole pericycle cells where lateral roots originate, and demonstrated that expression of several of these targets was required for normal root development. We also discovered novel subpopulations of cells in the pericycle and endodermal cell files that respond to lateral root initiation, highlighting the coordination across cell files required for this fate transition.One sentence summarySingle cell RNA sequencing reveals new molecular details about lateral root initiation, including the transcriptional impacts of the primordia on bordering cells.

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