UDP-GLYCOSYLTRANSFERASE 72E3 Plays a Role in Lignification of Secondary Cell Walls in Arabidopsis

Lignin is present in plant secondary cell walls and is among the most abundant biological polymers on Earth. In this work we investigated the potential role of the UGT72E gene family in regulating lignification in Arabidopsis. Chemical determination of floral stem lignin contents in ugt72e1, ugt72e2, and ugt72e3 mutants revealed no significant differences compared to WT plants. In contrast, the use of a novel safranin O ratiometric imaging technique indicated a significant increase in the cell wall lignin content of both interfascicular fibers and xylem from young regions of ugt72e3 mutant floral stems. These results were globally confirmed in interfascicular fibers by Raman microspectroscopy. Subsequent investigation using a bioorthogonal triple labelling strategy suggested that the augmentation in lignification was associated with an increased capacity of mutant cell walls to incorporate H-, G-, and S-monolignol reporters. Expression analysis showed that this increase was associated with an up-regulation of LAC17 and PRX71, which play a key role in lignin polymerization. Altogether, these results suggest that UGT72E3 can influence the kinetics of lignin deposition by regulating monolignol flow to the cell wall as well as the potential of this compartment to incorporate monomers into the growing lignin polymer.

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Lignification of spruce tracheid secondary cell walls related to longitudinal hardness and modulus of elasticity using nano-indentation

Canadian Journal of Botany ◽

10.1139/b02-091 ◽

2002 ◽

Vol 80 (10) ◽

pp. 1029-1033 ◽

Cited By ~ 41

Author(s):

W Gindl ◽

H S Gupta ◽

C Grünwald

Keyword(s):

Cell Wall ◽

Modulus Of Elasticity ◽

Cell Walls ◽

Secondary Cell Wall ◽

Lignin Content ◽

Wood Formation ◽

Nano Indentation ◽

Secondary Cell Walls ◽

Cell Wall Development ◽

The One

The lignin content and the mechanical properties of lignifying and fully lignified spruce tracheid secondary cell walls were determined using UV microscopy and nano-indentation, respectively. The average lignin content of developing tracheids was 0.10 g·g1, as compared with 0.21 g·g1 in mature tracheids. The modulus of elasticity of developing cells was on average 22% lower than the one measured in mature, fully lignified cells. For the longitudinal hardness, a larger difference of 26% was observed. As lignifying cells in the cambial zone are undergoing cell wall development, spaces in the cellulosehemicellulose structure are filled with lignin and the density of the cell wall is believed to increase. It is therefore suggested that the observed difference in modulus of elasticity between developing and fully lignified cell walls is due to the filling of spaces with lignin and an increase of the packing density of the cell wall during lignification. Although remarkably less stiff than the composite polysaccharide structure in the secondary cell wall, lignin may be considered equally hard. Therefore, the observed increase in lignin content may contribute directly to the measured increase of hardness.Key words: secondary cell wall, hardness, lignin, modulus of elasticity, wood formation.

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Comparing Mechanical Properties of Normal and Compression Wood in Norway Spruce: The Role of Lignin in Compression Parallel to the Grain

Holzforschung ◽

10.1515/hf.2002.062 ◽

2002 ◽

Vol 56 (4) ◽

pp. 395-401 ◽

Cited By ~ 26

Author(s):

W. Gindl

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Cell Wall ◽

Mechanical Testing ◽

Cell Walls ◽

Compression Wood ◽

Lignin Content ◽

Microfibril Angle ◽

Compression Failure

Summary Cell-wall lignin content and composition, as well as microfibril angle of normal and compression wood samples were determined prior to mechanical testing in compression parallel to the grain. No effect of increased lignin content on the Young's modulus in compression wood was discernible because of the dominating influence of microfibril angle. In contrast, compressive strength of compression wood was not negatively affected by the high microfibril angle. It is proposed that the observed high lignification in compression wood increases the resistance of the cell walls to compression failure. An increased percentage of p-hydroxyphenylpropane units observed in compression wood lignin may also contribute to the comparably high compressive strength of compression wood.

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Silicification of wood-cell walls

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100169870 ◽

1994 ◽

Vol 52 ◽

pp. 428-429

Author(s):

S. E. Keckler ◽

D. M. Dabbs ◽

N. Yao ◽

I. A. Aksay

Keyword(s):

Electron Microscopy ◽

Cell Wall ◽

Cell Walls ◽

Lignin Content ◽

Resin Composite ◽

Middle Lamella ◽

Cellulose Fibers ◽

Complex Structures ◽

Rich Region ◽

Inorganic Precursors

Cellular organic structures such as wood can be used as scaffolds for the synthesis of complex structures of organic/ceramic nanocomposites. The wood cell is a fiber-reinforced resin composite of cellulose fibers in a lignin matrix. A single cell wall, containing several layers of different fiber orientations and lignin content, is separated from its neighboring wall by the middle lamella, a lignin-rich region. In order to achieve total mineralization, deposition on and in the cell wall must be achieved. Geological fossilization of wood occurs as permineralization (filling the void spaces with mineral) and petrifaction (mineralizing the cell wall as the organic component decays) through infiltration of wood with inorganics after growth. Conversely, living plants can incorporate inorganics into their cells and in some cases into the cell walls during growth. In a recent study, we mimicked geological fossilization by infiltrating inorganic precursors into wood cells in order to enhance the properties of wood. In the current work, we use electron microscopy to examine the structure of silica formed in the cell walls after infiltration of tetraethoxysilane (TEOS).

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Hypolignification: A Decisive Factor in the Development of Hyperhydricity

Plants ◽

10.3390/plants10122625 ◽

2021 ◽

Vol 10 (12) ◽

pp. 2625

Author(s):

Nurashikin Kemat ◽

Richard G. F. Visser ◽

Frans A. Krens

Keyword(s):

Cell Wall ◽

Lignin Content ◽

Coumaric Acid ◽

Wild Type ◽

Higher Plant ◽

Gene Coding ◽

Phenylpropanoid Biosynthesis ◽

Total Lignin ◽

Total Lignin Content

One of the characteristics of hyperhydric plants is the reduction of cell wall lignification (hypolignification), but how this is related to the observed abnormalities of hyperhydricity (HH), is still unclear. Lignin is hydrophobic, and we speculate that a reduction in lignin levels leads to more capillary action of the cell wall and consequently to more water in the apoplast. p-coumaric acid is the hydroxyl derivative of cinnamic acid and a precursor for lignin and flavonoids in higher plant. In the present study, we examined the role of lignin in the development of HH in Arabidopsis thaliana by checking the wild-types (Ler and Col-0) and mutants affected in phenylpropanoid biosynthesis, in the gene coding for cinnamate 4-hydroxylase, C4H (ref3-1 and ref3-3). Exogenously applied p-coumaric acid decreased the symptoms of HH in both wild-type and less-lignin mutants. Moreover, the results revealed that exogenously applied p-coumaric acid inhibited root growth and increased the total lignin content in both wild-type and less-lignin mutants. These effects appeared to diminish the symptoms of HH and suggest an important role for lignin in HH.

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The effects of thermal treatment on the nanomechanical behavior of bamboo (Phyllostachys pubescens Mazel ex H. de Lehaie) cell walls observed by nanoindentation, XRD, and wet chemistry

Holzforschung ◽

10.1515/hf-2016-0124 ◽

2017 ◽

Vol 71 (2) ◽

pp. 129-135 ◽

Cited By ~ 15

Author(s):

Yanjun Li ◽

Chengjian Huang ◽

Li Wang ◽

Siqun Wang ◽

Xinzhou Wang

Keyword(s):

Cell Wall ◽

Thermal Treatment ◽

Cell Walls ◽

Treatment Time ◽

Lignin Content ◽

Phyllostachys Pubescens ◽

X Ray Diffraction ◽

Wet Chemistry ◽

X Ray ◽

Wet Chemical

Abstract The effects of thermal treatment of bamboo at 130, 150, 170, and 190°C for 2, 4, and 6 h were investigated in terms of changes in chemical composition, cellulose crystallinity, and mechanical behavior of the cell-wall level by means of wet chemical analysis, X-ray diffraction (XRD), and nanoindentation (NI). Particularly, the reduced elastic modulus (Er), hardness (H), and creep behavior were in focus. Both the temperature and treatment time showed significant effects. Expectedly, the hemicelluloses were degraded and the relative lignin content was elevated, while the crystallinity of the cellulose moiety was increased upon thermal treatment. The Er and H data of the cell wall were increased after 6 h treatment at 190°C, from 18.4 to 22.0 GPa and from 0.45 to 0.65 GPa, respectively. The thermal treatment led to a decrease of the creep ratio (CIT) under the same conditions by ca. 28%. The indentation strain state (εi) also decreased significantly after thermal treatment during the load-holding stage.

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Determination of transport constants of isolated Nitella cell walls

Canadian Journal of Botany ◽

10.1139/b68-054 ◽

1968 ◽

Vol 46 (4) ◽

pp. 317-327 ◽

Cited By ~ 21

Author(s):

M. T. Tyree

Keyword(s):

Activation Energy ◽

Cell Wall ◽

Diffusion Coefficient ◽

Cell Walls ◽

Transport Coefficients ◽

Irreversible Thermodynamics ◽

Kcal Mole ◽

Limiting Value ◽

Nitella Flexilis

Transport coefficients LPP, LPE, LEP, and LEE for electrokinetic equations according to irreversible thermodynamics, the Onsager coefficients, were measured for isolated Nitella flexilis cell walls in KCl solutions ranging from 10−4 to 100 normal. LPP and LPE (= LEP) were found to be independent of KCl concentration and equal to 1.4 × 10−6 cm3 sec−1 cm−2 (joule cm−3)−1 cm and 6 × 10−5 cm3 sec−1 cm−2 volt−1 cm respectively. LEE was a function of the salt concentration, reaching a limiting value of about 1.2 × 10−3 mho cm−1 in 10−4 N KCl. The activation energy for movement of KCl in cell walls was found to be 4.33 Kcal mole−1; the diffusion coefficient for KCl in cell walls was calculated by two methods to be 8 × 10−6 cm2 sec−1; and the concentration of the fixed ions in Nitella cell walls from the above data was estimated at greater than 0.04 equivalent per liter of cell wall. Electroosmosis in Nitella membranes is re-examined in the light of the measured transport coefficients and it is concluded that under proper conditions the cell wall of Nitella can contribute significantly (~20% or more) to the observed electroosmosis of living Nitella cells.

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LYSOZYME SENSITIVITY OF THE CELL WALL OF PSEUDO-MONAS AERUGINOSA: FURTHER EVIDENCE FOR THE ROLE OF THE NON-PEPTIDOGLYCAN COMPONENTS IN CELL WALL RIGIDITY

Canadian Journal of Microbiology ◽

10.1139/m66-015 ◽

1966 ◽

Vol 12 (1) ◽

pp. 105-108 ◽

Cited By ~ 18

Author(s):

K. Jane Carson ◽

R. G. Eagon

Keyword(s):

Pseudomonas Aeruginosa ◽

Cell Wall ◽

Electron Micrographs ◽

Cell Walls ◽

Gram Negative Bacteria ◽

Normal Cells ◽

Thin Sections ◽

Gram Negative ◽

Cell Wall Rigidity

Electron micrographs of thin sections of normal cells of Pseudomonas aeruginosa showed the cell walls to be convoluted and to be composed of two distinct layers. Electron micrographs of thin sections of lysozyme-treated cells of P. aeruginosa showed (a) that the cell walls lost much of their convoluted nature; (b) that the layers of the cell walls became diffuse and less distinct; and (c) that the cell walls became separated from the protoplasts over extensive cellular areas. These results suggest that the peptidoglycan component of the unaltered cell walls of P. aeruginosa is sensitive to lysozyme. Furthermore, it appears that the peptidoglycan component is not solely responsible for the rigidity of the cell walls of Gram-negative bacteria.

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

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1613273113 ◽

2016 ◽

Vol 113 (40) ◽

pp. 11348-11353 ◽

Cited By ~ 50

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.

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The fate of acetyl groups and sugar components during the digestion of grass cell walls in sheep

The Journal of Agricultural Science ◽

10.1017/s0021859600028252 ◽

1977 ◽

Vol 89 (2) ◽

pp. 327-340 ◽

Cited By ~ 55

Author(s):

E. Jane Morris ◽

J. S. D. Bacon

Keyword(s):

Cell Wall ◽

Cell Walls ◽

Lignin Content ◽

Sodium Ethoxide ◽

Mesophyll Cell ◽

Cell Types ◽

Gas Liquid Chromatography ◽

Cell Wall Preparation ◽

The Relationship ◽

Isolated Cell

SummaryThe digestibilities of grass cell wall constituents determined in a digestion trial were compared with those obtained by suspending various isolated cell wall preparations in nylon bags in the rumen of a sheep. Particular attention was paid to acetyl groups and to individual sugars, which were determined in both cases by gas liquid chromatography.For dried grass and hay in the digestion trial the cell wall constituents showed digestibilities decreasing in the following order: arabinose, galactose, glucose, xylose, acetyl, lignin.For a leaf cell wall preparation derived from all cell types except mesophyll, the nylon bag technique allowed the same order of digestibilities; rhamnose and uronic acids were also measured and found to be rapidly digested. Mesophyll cell walls placed in nylon bags were more readily digested than non-mesophyll. All the sugars, and also acetyl groups, were digested to the same extent.In a grass cell wall preparation isolated from sheep faeces, tested similarly, xylose and glucose were digested to the same extent, but acetyl groups were less digested.Removal of acetyl groups, using sodium ethoxide, which left the sugar composition and lignin content unchanged, increased the digestibility particularly of the cell walls from faeces.The results are discussed with reference to the relationship between cell wall composition and digestibility.

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Structural imaging of native cryo-preserved secondary cell walls reveals presence of macrofibrils composed of cellulose, lignin and xylan

10.1101/648360 ◽

2019 ◽

Author(s):

Jan J. Lyczakowski ◽

Matthieu Bourdon ◽

Oliver M. Terrett ◽

Ykä Helariutta ◽

Raymond Wightman ◽

...

Keyword(s):

Cell Wall ◽

Cell Walls ◽

Structural Imaging ◽

Cylindrical Structures ◽

Fibril Structure ◽

Secondary Cell Walls ◽

Additional Approach ◽

Temperature Scanning ◽

Mutant Lines ◽

Bearing Structure

AbstractThe woody secondary cell walls of plants are the largest repository of renewable carbon biopolymers on the planet. These walls are made principally from cellulose and hemicelluloses and are impregnated with lignin. Despite their importance as the main load bearing structure for plant growth, as well as their industrial importance as both a material and energy source, the precise arrangement of these constituents within the cell wall is not yet fully understood. We have adapted low temperature scanning electron microscopy (cryo-SEM) for imaging the nanoscale architecture of angiosperm and gymnosperm cell walls in their native hydrated state. Our work confirms that cell wall macrofibrils, cylindrical structures with a diameter exceeding 10 nm, are a common feature of the native hardwood and softwood samples. We have observed these same structures in Arabidopsis thaliana secondary cell walls, enabling macrofibrils to be compared between mutant lines that are perturbed in cellulose, hemicellulose and lignin formation. Our analysis indicates that the macrofibrils in Arabidopsis cell walls are composed, at least partially, of cellulose, xylan and lignin. This study is a useful additional approach for investigating the native nanoscale architecture and composition of hardwood and softwood secondary cell walls and demonstrates the applicability of Arabidopsis genetic resources to relate fibril structure with wall composition and biosynthesis.

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