scholarly journals Changes in cell ultrastructure and morphology of Arabidopsis thaliana roots after coumarins treatment

2014 ◽  
Vol 70 (3) ◽  
pp. 187-198
Author(s):  
Ewa Kupidłowska
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Cell Walls ◽  
Root Elongation ◽  
Inhibitory Effect ◽  
Cell Ultrastructure ◽  
Radial Expansion ◽  
Elongation Zone ◽  
Cortical Cells ◽  
Mother Cell Wall

The ultrastructure and morphology of roots treated with coumarin and umbelliferone as well as the reversibility of the coumarins effects caused by exogenous GA, were studied in <em>Arabidopsis thaliana</em>. Both coumarins suppressed root elongation and appreciably stimulated radial expansion of epidermal and cortical cells in the upper part of the meristem and in the elongation zone. The gibberellic acid applied simultaneously with coumarins decreased their inhibitory effect on root elongation and reduced cells swelling.Microscopic observation showed intensive vacuolization of cells and abnormalities in the structure of the Golgi stacks and the nuclear envelope. The detection of active acid phosphatase in the cytosol of swollen cells indicated increased membrane permeability. Significant abnormalities of newly formed cell walls, e.g. the discontinuity of cellulose layer, uncorrect position of walls and the lack of their bonds with the mother cell wall suggest that coumarins affected the cytoskeleton.

scholarly journals Multi-omics analysis identifies genes mediating the extension of cell walls in the Arabidopsis thaliana root elongation zone

2015 ◽  
Vol 3 ◽  
Author(s):  
Michael H. Wilson ◽  
Tara J. Holman ◽  
Iben Sørensen ◽  
Ester Cancho-Sanchez ◽  
Darren M. Wells ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Walls ◽  
Root Elongation ◽  
Elongation Zone ◽  
Omics Analysis

scholarly journals Two Expansin Genes, AtEXPA4 and AtEXPB5, Are Redundantly Required for Pollen Tube Growth and AtEXPA4 Is Involved in Primary Root Elongation in Arabidopsis thaliana

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 249
Author(s):  
Weimiao Liu ◽  
Liai Xu ◽  
Hui Lin ◽  
Jiashu Cao
Keyword(s):  
Arabidopsis Thaliana ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Cell Walls ◽  
Root Elongation ◽  
Expression Patterns ◽  
Primary Root ◽  
Pollen Grains ◽  
Tube Growth ◽  
Cell Wall Binding

The growth of plant cells is inseparable from relaxation and expansion of cell walls. Expansins are a class of cell wall binding proteins, which play important roles in the relaxation of cell walls. Although there are many members in expansin gene family, the functions of most expansin genes in plant growth and development are still poorly understood. In this study, the functions of two expansin genes, AtEXPA4 and AtEXPB5 were characterized in Arabidopsis thaliana. AtEXPA4 and AtEXPB5 displayed consistent expression patterns in mature pollen grains and pollen tubes, but AtEXPA4 also showed a high expression level in primary roots. Two single mutants, atexpa4 and atexpb5, showed normal reproductive development, whereas atexpa4atexpb5 double mutant was defective in pollen tube growth. Moreover, AtEXPA4 overexpression enhanced primary root elongation, on the contrary, knocking out AtEXPA4 made the growth of primary root slower. Our results indicated that AtEXPA4 and AtEXPB5 were redundantly involved in pollen tube growth and AtEXPA4 was required for primary root elongation.

scholarly journals The Arabidopsis TETRATRICOPEPTIDE THIOREDOXIN-LIKE 1 Gene Is Involved in Anisotropic Root Growth during Osmotic Stress Adaptation

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 236
Author(s):  
María Belén Cuadrado-Pedetti ◽  
Inés Rauschert ◽  
María Martha Sainz ◽  
Vítor Amorim-Silva ◽  
Miguel Angel Botella ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Root Growth ◽  
Cell Walls ◽  
Primary Root ◽  
Stress Adaptation ◽  
Elongation Zone ◽  
Cortical Cells ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Mean

Mutations in the Arabidopsis TETRATRICOPEPTIDE THIOREDOXIN-LIKE 1 (TTL1) gene cause reduced tolerance to osmotic stress evidenced by an arrest in root growth and root swelling, which makes it an interesting model to explore how root growth is controlled under stress conditions. We found that osmotic stress reduced the growth rate of the primary root by inhibiting the cell elongation in the elongation zone followed by a reduction in the number of cortical cells in the proximal meristem. We then studied the stiffness of epidermal cell walls in the root elongation zone of ttl1 mutants under osmotic stress using atomic force microscopy. In plants grown in control conditions, the mean apparent elastic modulus was 448% higher for live Col-0 cell walls than for ttl1 (88.1 ± 2.8 vs. 16.08 ± 6.9 kPa). Seven days of osmotic stress caused an increase in the stiffness in the cell wall of the cells from the elongation zone of 87% and 84% for Col-0 and ttl1, respectively. These findings suggest that TTL1 may play a role controlling cell expansion orientation during root growth, necessary for osmotic stress adaptation.

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 Domain-specific and cell type-specific localization of two types of cell wall matrix polysaccharides in the clover root tip.

1992 ◽  
Vol 118 (2) ◽  
pp. 467-479 ◽  
Author(s):  
M A Lynch ◽  
L A Staehelin
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Cellular Differentiation ◽  
Cortical Cell ◽  
Middle Lamella ◽  
Root Cap ◽  
Root Tip ◽  
Cortical Cells ◽  
Peripheral Cell ◽  
Clover Root

Using immunocytochemical techniques and antibodies that specifically recognize xyloglucan (anti-XG), polygalacturonic acid/rhamnogalacturonan I (anti-PGA/RG-I), and methylesterified pectins (JIM 7), we have shown that these polysaccharides are differentially synthesized and localized during cell development and differentiation in the clover root tip. In cortical cells XG epitopes are present at a threefold greater density in the newly formed cross walls than in the older longitudinal walls, and PGA/RG-I epitopes are detected solely in the expanded middle lamella of cortical cell corners, even after pretreatment of sections with pectinmethylesterase to uncover masked epitopes. These results suggest that in cortical cells XG and PGA/RG-I are differentially localized not only to particular wall domains, but also to particular cell walls. In contrast to their nonoverlapping distribution in cortical cells, XG epitopes and PGA/RG-I epitopes largely colocalize in the epidermal cell walls. The results also demonstrate that the middle lamella of the longitudinal walls shared by epidermal cells and by epidermal and cortical cells constitutes a barrier to the diffusion of cell wall and mucilage molecules. Synthesis of XG and PGA/RG-I epitope-containing polysaccharides also varies during cellular differentiation in the root cap. The differentiation of gravitropic columella cells into mucilage-secreting peripheral cells is marked by a dramatic increase in the synthesis and secretion of molecules containing XG and PGA/RG-I epitopes. In contrast, JIM 7 epitopes are present at abundant levels in columella cell walls, but are not detectable in peripheral cell walls or in secreted mucilage. There were also changes in the cisternal labeling of the Golgi stacks during cellular differentiation in the root tip. Whereas PGA/RG-I epitopes are detected primarily in cis- and medial Golgi cisternae in cortical cells (Moore, P. J., K. M. M. Swords, M. A. Lynch, and L. A. Staehelin. 1991. J. Cell Biol. 112:589-602), they are localized predominantly in the trans-Golgi cisternae and the trans-Golgi network in epidermal and peripheral root cap cells. These observations suggest that during cellular differentiation the plant Golgi apparatus can be both structurally and functionally reorganized.

scholarly journals Cell Wall Proteome in the Maize Primary Root Elongation Zone. I. Extraction and Identification of Water-Soluble and Lightly Ionically Bound Proteins

2005 ◽  
Vol 140 (1) ◽  
pp. 311-325 ◽  
Author(s):  
Jinming Zhu ◽  
Sixue Chen ◽  
Sophie Alvarez ◽  
Victor S. Asirvatham ◽  
Daniel P. Schachtman ◽  
...  
Keyword(s):  
Cell Wall ◽  
Root Elongation ◽  
Primary Root ◽  
Water Soluble ◽  
Elongation Zone ◽  
Cell Wall Proteome

scholarly journals Cytokinesis in fra2 Arabidopsis thaliana p60-katanin Mutant: Defects in Cell Plate/Daughter Wall Formation

2021 ◽  
Author(s):  
Emmanuel Panteris ◽  
Anna Kouskouveli ◽  
Dimitris Pappas ◽  
Ioannis-Dimosthenis S. Adamakis
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Cell Walls ◽  
Higher Plants ◽  
Cell Plate ◽  
Wild Type ◽  
Microtubule Organization ◽  
Root Cells ◽  
Wall Formation ◽  
In The Wild

Cytokinesis is accomplished in higher plants by the phragmoplast, creating and conducting the cell plate, to separate daughter nuclei by a new cell wall. The microtubule-severing enzyme p60-katanin plays an important role in the centrifugal expansion and timely disappearance of phragmoplast microtubules. Consequently, aberrant structure and delayed expansion rate of the phragmoplast occur in p60-katanin mutants. Here, the consequences of p60-katanin malfunction in cell plate/daughter wall formation were investigated by transmission electron microscopy (TEM), while deviations in the chemical composition of cell plate/new cell wall were identified by immunolabeling and confocal microscopy, in root cells of the fra2 Arabidopsis thaliana mutant. It was found that, apart from defective phragmoplast microtubule organization, cell plates/new cell walls appeared also faulty in structure, being unevenly thick and perforated by large gaps. In addition, demethylesterified homogalacturonans were prematurely present in fra2 cell plates, while callose content was significantly lower than in the wild-type. Furthermore, KNOLLE syntaxin disappeared from newly formed cell walls in fra2 earlier than in the wild-type. Taken together, these observations indicate that delayed cytokinesis, due to faulty phragmoplast organization and expansion, results in a loss of synchronization between cell plate growth and its chemical maturation.

scholarly journals Post-Synthetic Reduction of Pectin Methylesterification Causes Morphological Abnormalities and Alterations to Stress Response in Arabidopsis thaliana

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1558
Author(s):  
Nathan T. Reem ◽  
Lauran Chambers ◽  
Ning Zhang ◽  
Siti Farah Abdullah ◽  
Yintong Chen ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Plant Cell ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Normal Growth ◽  
Pectin Methylesterase ◽  
Dwarf Phenotype ◽  
Response To Stress ◽  
Defense Response Genes

Pectin is a critical component of the plant cell wall, supporting wall biomechanics and contributing to cell wall signaling in response to stress. The plant cell carefully regulates pectin methylesterification with endogenous pectin methylesterases (PMEs) and their inhibitors (PMEIs) to promote growth and protect against pathogens. We expressed Aspergillus nidulans pectin methylesterase (AnPME) in Arabidopsis thaliana plants to determine the impacts of methylesterification status on pectin function. Plants expressing AnPME had a roughly 50% reduction in methylester content compared with control plants. AnPME plants displayed a severe dwarf phenotype, including small, bushy rosettes and shorter roots. This phenotype was caused by a reduction in cell elongation. Cell wall composition was altered in AnPME plants, with significantly more arabinose and significantly less galacturonic acid, suggesting that plants actively monitor and compensate for altered pectin content. Cell walls of AnPME plants were more readily degraded by polygalacturonase (PG) alone but were less susceptible to treatment with a mixture of PG and PME. AnPME plants were insensitive to osmotic stress, and their susceptibility to Botrytis cinerea was comparable to wild type plants despite their compromised cell walls. This is likely due to upregulated expression of defense response genes observed in AnPME plants. These results demonstrate the importance of pectin in both normal growth and development, and in response to biotic and abiotic stresses.

scholarly journals On a Malay Form of Chlorococcum humicola (Näg.), Rabenh

1919 ◽  
Vol 44 (299) ◽  
pp. 473-482 ◽  
Author(s):  
B. Muriel Bristol
Keyword(s):  
Cell Wall ◽  
Mother Cell ◽  
Cell Walls ◽  
Starch Granules ◽  
Red Pigment ◽  
Vegetative Cells ◽  
Daughter Cells ◽  
Set Up ◽  
Mother Cell Wall ◽  
Adult Cells

Summary The material described has been obtained from cultures of a sample of dried soil, which was sent from the Malay States about two years before the cultures were set up. The vegetative cells are spherical or subspherical, solitary or collected together into mucilaginous strata, very variable in size, being from 20–80 μ in diameter, each with a thin cellulose cell-wall and a single parietal chloroplast containing from one to several pyrenoids and numerous starch granules. In adult cells a quantity of yellow oil is stored, in which a bright red pigment is often dissolved. The cytoplasm is reticulate. The young cells contain a single minute nucleus and one pyrenoid, both of which multiply by repeated division so that the adult cells are cœnocytic with many pyrenoids. Propagation takes place, by successive bipartition of the contents of the mother-cell, into 8–16 or numerous biciliate zoogonidia which may develop asexually or may act as facultative gametes. In both cases direct development into vegetative cells takes place. Aplanospore-formation may also take place, preceded by the multiplication by constriction of the nuclei of the mother-cell. The aplanospores remain imbedded in a mucous stratum, and enter into a palmelloid state in which further bipartitions may take place. Eventually, the palmelloid cells either acquire cilia and behave as normal zoogonidia or they develop directly into vegetative cells. True vegetative division does not take place, but the cell-contents may divide into two daughter-cells which immediately acquire new cell-walls and are set free as vegetative cells by the dissolution of the mother-cell-wall. Chloroaoccum humicola, differing in no essential particulars from that in the Malay soil, has been found to occur almost universally in English soils. The limit of its resistance against desiccation and of its retention of vitality has been shown, by investigations on long-dried English soils, to lie somewhere between seventy and eighty years. In conclusion, I wish to express my thanks to Professor G. S. West for his valuable help throughout this work.

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