Direct visualization of cross-links in the primary plant cell wall

1990 ◽  
Vol 96 (2) ◽  
pp. 323-334 ◽  
Author(s):  
M. C. MCCANN ◽  
B. WELLS ◽  
K. ROBERTS
Keyword(s):  
Cell Wall ◽  
Plant Cell Wall ◽  
Three Dimensional ◽  
Preliminary Evidence ◽  
Cellulose Microfibrils ◽  
Primary Cell Wall ◽  
Positive Role ◽  
Extraction Step ◽  
Cross Links ◽  
Wall Construction

We have investigated the structure of the onion primary cell wall at high resolution, using shadowed replicas of rapidly frozen deep-etched specimens. We have sequentially extracted polymers from the wall and have visualized both these and the remaining structures at each extraction step. By viewing the structures in as near their native state as possible, an accurate three-dimensional picture of wall construction has been assembled, facilitated by viewing stereo pairs of micrographs. Our observations show that the physical links between cellulose microfibrils that we observe in the intact wall are generally shorter (20–40 nm) than the isolated molecules we extract (30->700nm), suggesting that lateral interactions must occur between linking polymers and cellulose in muro. These cross-links are hemicellulosic and we believe them to be xyloglucans: their removal allows increased lateral association of microfibrils. Na2CO3-extractable pectic fractions form a separate coextensive network, the removal of which does not affect basic cellulose/ hemicellulose architecture. Preliminary evidence for a lamellate model of wall construction has been obtained. In addition, we propose a positive role for hemicellulose in maintaining the ordered spacing of cellulose micronbrils, perhaps regulating wall porosity and strength. The basic wall parameters that we derive impose constraints on possible cell wall models.

The three-dimensional structure of the cell wall glycoprotein of Chlorogonium elongatum

1984 ◽  
Vol 68 (1) ◽  
pp. 271-284
Author(s):  
P.J. Shaw ◽  
G.J. Hills
Keyword(s):  
Cell Wall ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Dimensional Structure ◽  
Primary Cell Wall ◽  
Globular Domain ◽  
Higher Plant ◽  
Intersubunit Interactions

The green alga Chlorogonium elongatum, a member of the Volvocales, possesses a crystalline cell wall composed of hydroxyproline-rich glycoprotein similar to the primary cell wall glycoproteins of higher plants. Electron microscopy and computer image processing have been used to determine the crystal structure of the Chlorogonium cell wall in three dimensions to a resolution of 2.0 nm. The structure is composed of heterologous dimers. Each subunit of the dimer comprises a long, thin spacer domain and a large globular domain, which is the site of the intra- and inter-dimer interactions. There are also sites of intersubunit interactions at the opposite ends of the rod domains. We suggest that the rods are composed predominantly of glycosylated polyproline helix, as has been suggested for higher plant cell wall glycoproteins and has been shown for the cell wall glycoprotein of Chlamydomonas reinhardtii, which is closely related to Chlorogonium.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

scholarly journals Catalysts of plant cell wall loosening

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 119 ◽  
Author(s):  
Daniel J. Cosgrove
Keyword(s):  
Cell Wall ◽  
Plant Cell Wall ◽  
Turgor Pressure ◽  
Wall Stress ◽  
Primary Cell Wall ◽  
Wall Structure ◽  
Xyloglucan Endotransglycosylase ◽  
Growing Cell ◽  
Tensile Forces ◽  
Wall Loosening

The growing cell wall in plants has conflicting requirements to be strong enough to withstand the high tensile forces generated by cell turgor pressure while selectively yielding to those forces to induce wall stress relaxation, leading to water uptake and polymer movements underlying cell wall expansion. In this article, I review emerging concepts of plant primary cell wall structure, the nature of wall extensibility and the action of expansins, family-9 and -12 endoglucanases, family-16 xyloglucan endotransglycosylase/hydrolase (XTH), and pectin methylesterases, and offer a critical assessment of their wall-loosening activity

scholarly journals Cellulose synthase interactive1- and microtubule-dependent cell wall architecture is required for acid growth in Arabidopsis hypocotyls

2020 ◽  
Vol 71 (10) ◽  
pp. 2982-2994 ◽  
Author(s):  
Xiaoran Xin ◽  
Lei Lei ◽  
Yunzhen Zheng ◽  
Tian Zhang ◽  
Sai Venkatesh Pingali ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Elongation ◽  
Plant Cell Wall ◽  
Cellulose Microfibrils ◽  
Crystalline Cellulose ◽  
Cellulose Content ◽  
Acid Growth ◽  
Cell Wall Assembly ◽  
Dependent Cell ◽  
Cell Wall Architecture

Abstract Auxin-induced cell elongation relies in part on the acidification of the cell wall, a process known as acid growth that presumably triggers expansin-mediated wall loosening via altered interactions between cellulose microfibrils. Cellulose microfibrils are a major determinant for anisotropic growth and they provide the scaffold for cell wall assembly. Little is known about how acid growth depends on cell wall architecture. To explore the relationship between acid growth-mediated cell elongation and plant cell wall architecture, two mutants (jia1-1 and csi1-3) that are defective in cellulose biosynthesis and cellulose microfibril organization were analyzed. The study revealed that cell elongation is dependent on CSI1-mediated cell wall architecture but not on the overall crystalline cellulose content. We observed a correlation between loss of crossed-polylamellate walls and loss of auxin- and fusicoccin-induced cell growth in csi1-3. Furthermore, induced loss of crossed-polylamellate walls via disruption of cortical microtubules mimics the effect of csi1 in acid growth. We hypothesize that CSI1- and microtubule-dependent crossed-polylamellate walls are required for acid growth in Arabidopsis hypocotyls.

Plant cell wall construction crew

Science ◽  
2020 ◽  
Vol 369 (6507) ◽  
pp. 1069.2-1069
Author(s):  
Michael A. Funk
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Wall Construction

scholarly journals Direct evidence for a new mode of plant defense against insects via a novel polygalacturonase-inhibiting protein expression strategy

2020 ◽  
Vol 295 (33) ◽  
pp. 11833-11844
Author(s):  
Wiebke Haeger ◽  
Jana Henning ◽  
David G. Heckel ◽  
Yannick Pauchet ◽  
Roy Kirsch
Keyword(s):  
Cell Wall ◽  
Plant Defense ◽  
Plant Cell Wall ◽  
Direct Evidence ◽  
Larval Growth ◽  
Gene Families ◽  
Preliminary Evidence ◽  
Cell Wall Polysaccharide ◽  
In Planta

Plant cell wall–associated polygalacturonase-inhibiting proteins (PGIPs) are widely distributed in the plant kingdom. They play a crucial role in plant defense against phytopathogens by inhibiting microbial polygalacturonases (PGs). PGs hydrolyze the cell wall polysaccharide pectin and are among the first enzymes to be secreted during plant infection. Recent studies demonstrated that herbivorous insects express their own PG multi-gene families, raising the question whether PGIPs also inhibit insect PGs and protect plants from herbivores. Preliminary evidence suggested that PGIPs may negatively influence larval growth of the leaf beetle Phaedon cochleariae (Coleoptera: Chrysomelidae) and identified BrPGIP3 from Chinese cabbage (Brassica rapa ssp. pekinensis) as a candidate. PGIPs are predominantly studied in planta because their heterologous expression in microbial systems is problematic and instability and aggregation of recombinant PGIPs has complicated in vitro inhibition assays. To minimize aggregate formation, we heterologously expressed BrPGIP3 fused to a glycosylphosphatidylinositol (GPI) membrane anchor, immobilizing it on the extracellular surface of insect cells. We demonstrated that BrPGIP3_GPI inhibited several P. cochleariae PGs in vitro, providing the first direct evidence of an interaction between a plant PGIP and an animal PG. Thus, plant PGIPs not only confer resistance against phytopathogens, but may also aid in defense against herbivorous beetles.

scholarly journals Primary cell wall inspired micro containers as a step towards a synthetic plant cell

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
T. Paulraj ◽  
S. Wennmalm ◽  
D.C.F. Wieland ◽  
A. V. Riazanova ◽  
A. Dėdinaitė ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Structural Integrity ◽  
Plant Cells ◽  
Lipid Vesicles ◽  
Primary Cell Wall ◽  
Living Plant ◽  
A Cell ◽  
Lipid Tubules

AbstractThe structural integrity of living plant cells heavily relies on the plant cell wall containing a nanofibrous cellulose skeleton. Hence, if synthetic plant cells consist of such a cell wall, they would allow for manipulation into more complex synthetic plant structures. Herein, we have overcome the fundamental difficulties associated with assembling lipid vesicles with cellulosic nanofibers (CNFs). We prepare plantosomes with an outer shell of CNF and pectin, and beneath this, a thin layer of lipids (oleic acid and phospholipids) that surrounds a water core. By exploiting the phase behavior of the lipids, regulated by pH and Mg2+ ions, we form vesicle-crowded interiors that change the outer dimension of the plantosomes, mimicking the expansion in real plant cells during, e.g., growth. The internal pressure enables growth of lipid tubules through the plantosome cell wall, which paves the way to the development of hierarchical plant structures and advanced synthetic plant cell mimics.

scholarly journals The pattern of xylan acetylation suggests xylan may interact with cellulose microfibrils as a twofold helical screw in the secondary plant cell wall of Arabidopsis thaliana

2014 ◽  
Vol 79 (3) ◽  
pp. 492-506 ◽  
Author(s):  
Marta Busse‐Wicher ◽  
Thiago C. F. Gomes ◽  
Theodora Tryfona ◽  
Nino Nikolovski ◽  
Katherine Stott ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Cellulose Microfibrils ◽  
Secondary Plant

scholarly journals Cellulose synthase complexes act in a concerted fashion to synthesize highly aggregated cellulose in secondary cell walls of plants

2016 ◽  
Vol 113 (40) ◽  
pp. 11348-11353 ◽  
Author(s):  
Shundai Li ◽  
Logan Bashline ◽  
Yunzhen Zheng ◽  
Xiaoran Xin ◽  
Shixin Huang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Cellulose Synthase ◽  
Cellulose Microfibrils ◽  
Critical Component ◽  
Distinct Structure ◽  
Secondary Cell Walls ◽  
Composition Structure ◽  
Membrane Spanning

Cellulose, often touted as the most abundant biopolymer on Earth, is a critical component of the plant cell wall and is synthesized by plasma membrane-spanning cellulose synthase (CESA) enzymes, which in plants are organized into rosette-like CESA complexes (CSCs). Plants construct two types of cell walls, primary cell walls (PCWs) and secondary cell walls (SCWs), which differ in composition, structure, and purpose. Cellulose in PCWs and SCWs is chemically identical but has different physical characteristics. During PCW synthesis, multiple dispersed CSCs move along a shared linear track in opposing directions while synthesizing cellulose microfibrils with low aggregation. In contrast, during SCW synthesis, we observed swaths of densely arranged CSCs that moved in the same direction along tracks while synthesizing cellulose microfibrils that became highly aggregated. Our data support a model in which distinct spatiotemporal features of active CSCs during PCW and SCW synthesis contribute to the formation of cellulose with distinct structure and organization in PCWs and SCWs of Arabidopsis thaliana. This study provides a foundation for understanding differences in the formation, structure, and organization of cellulose in PCWs and SCWs.

scholarly journals Golgi-localized GALT7 and GALT8 participate in cellulose biosynthesis

2021 ◽  
Author(s):  
Pieter Nibbering ◽  
Romain Castilleux ◽  
Gunnar Wingsle ◽  
Totte Niittylä
Keyword(s):  
Cell Wall ◽  
Golgi Apparatus ◽  
Secondary Cell Wall ◽  
Plant Cell Wall ◽  
Arabinogalactan Protein ◽  
Primary Cell Wall ◽  
Cellulose Content ◽  
Cellulose Biosynthesis ◽  
Cell Wall Assembly ◽  
Protein Levels

AbstractArabinogalactan protein (AGP) glycan biosynthesis in the Golgi apparatus contributes to plant cell wall assembly, but the mechanisms underlying this process are largely unknown. Here, we show that two putative galactosyltransferases -named GALT7 and GALT8 -from the glycosyltransferase family 31 (GT31) of Arabidopsis thaliana participate in cellulose biosynthesis. galt7galt8 mutants show primary cell wall defects manifesting as impaired growth and cell expansion in seedlings and etiolated hypocotyls, along with secondary cell wall defects, apparent as collapsed xylem vessels and reduced xylem wall thickness in the inflorescence stem. These phenotypes were associated with a ∼30% reduction in cellulose content, a ∼50% reduction in secondary cell wall CELLULOSE SYNTHASE (CESA) protein levels and reduced cellulose biosynthesis rate. CESA transcript levels were not significantly altered in galt7galt8 mutants, suggesting that the reduction in CESA levels was caused by a post-transcriptional mechanism. We provide evidence that both GALT7 and GALT8 localise to the Golgi apparatus, while quantitative proteomics experiments revealed reduced levels of the entire FLA subgroup B in the galt7galt8 mutants. This leads us to hypothesize that a defect in FLA subgroup B glycan biosynthesis reduces cellulose biosynthesis rate in galt7galt8 mutants.

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