Quantum Mechanical Calculations Suggest That Lignin Polymerization Is Kinetically Controlled

Lignin is an abundant biopolymer important for plant function while holding promise as a renewable source of valuable chemicals. Although the lignification process in plant cell walls has been long-studied, a comprehensive, mechanistic understanding on the molecular scale remains elusive. A better understanding of lignification will lead to improved atomistic models of the plant cell wall that could, in turn, inform effective strategies for biomass valorization. Here, using first-principles quantum chemical calculations, we show that a simple model of kinetically-controlled radical coupling broadly rationalizes qualitative experimental observations of lignin structure across a wide variety of biomass types, thus paving the way for predictive, first-principles models of lignification while highlighting the ability of computational chemistry to help illuminate complex biological processes.

Download Full-text

Plant Cell Wall Hydration and Plant Physiology: An Exploration of the Consequences of Direct Effects of Water Deficit on the Plant Cell Wall

Plants ◽

10.3390/plants10071263 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1263

Author(s):

David Stuart Thompson ◽

Azharul Islam

Keyword(s):

Cell Wall ◽

Water Content ◽

Bacterial Cellulose ◽

Plant Cell ◽

Cell Walls ◽

Plant Cell Wall ◽

Plant Cell Walls ◽

Cell Wall Polysaccharides ◽

Degree Of Hydration ◽

Cellulose Composites

The extensibility of synthetic polymers is routinely modulated by the addition of lower molecular weight spacing molecules known as plasticizers, and there is some evidence that water may have similar effects on plant cell walls. Furthermore, it appears that changes in wall hydration could affect wall behavior to a degree that seems likely to have physiological consequences at water potentials that many plants would experience under field conditions. Osmotica large enough to be excluded from plant cell walls and bacterial cellulose composites with other cell wall polysaccharides were used to alter their water content and to demonstrate that the relationship between water potential and degree of hydration of these materials is affected by their composition. Additionally, it was found that expansins facilitate rehydration of bacterial cellulose and cellulose composites and cause swelling of plant cell wall fragments in suspension and that these responses are also affected by polysaccharide composition. Given these observations, it seems probable that plant environmental responses include measures to regulate cell wall water content or mitigate the consequences of changes in wall hydration and that it may be possible to exploit such mechanisms to improve crop resilience.

Download Full-text

A Label-free, Fast and High-specificity Technique for Plant Cell Wall Imaging and Composition Analysis

10.21203/rs.3.rs-107437/v1 ◽

2020 ◽

Author(s):

Huimin Xu ◽

Yuanyuan Zhao ◽

Yuanzhen Suo ◽

Yayu Guo ◽

Yi Man ◽

...

Keyword(s):

Cell Wall ◽

Chemical Composition ◽

Raman Scattering ◽

Plant Cell ◽

Cell Walls ◽

Plant Cell Wall ◽

Composition Analysis ◽

Plant Cell Walls ◽

Label Free ◽

Wall Imaging

Abstract Background: Cell wall imaging can considerably permit direct visualization of the molecular architecture of cell walls and provide the detailed chemical information on wall polymers, which is imperative to better exploit and use the biomass polymers; however, detailed imaging and quantifying of the native composition and architecture in the cell wall remains challenging.Results: Here, we describe a label-free imaging technology, coherent Raman scattering microscopy (CRS), including coherent anti-Stokes Raman scattering (CARS) microscopy and stimulated Raman scattering (SRS) microscopy, which images the major structures and chemical composition of plant cell walls. The major steps of the procedure are demonstrated, including sample preparation, setting the mapping parameters, analysis of spectral data, and image generation. Applying this rapid approach, which will help researchers understand the highly heterogeneous structures and organization of plant cell walls.Conclusions: This method can potentially be incorporated into label-free microanalyses of plant cell wall chemical composition based on the in situ vibrations of molecules.

Download Full-text

Plant cell wall chemistry: implications for ruminant utilisation

Journal of Applied Animal Nutrition ◽

10.3920/jaan2020.0017 ◽

2021 ◽

pp. 1-26

Author(s):

X. Li

Keyword(s):

Plant Cell ◽

Cell Walls ◽

Plant Cell Wall ◽

Current Knowledge ◽

Plant Cell Walls ◽

Rumen Microorganisms ◽

Cell Wall Chemistry ◽

Fibre Degradation ◽

The Subject ◽

Composition Structure

Ruminants have adapted to cope with bulky, fibrous forage diets by accommodating a large, diverse microbial population in the reticulo-rumen. Ruminants are dependent on forages as their main sources of energy and other nutrients. Forages are comprised of a complex matrix of cellulose, hemicellulose, protein, minerals and phenolic compounds (including lignin and tannins) with various linkages; many of which are poorly defined. The composition and characteristics of polysaccharides vary greatly among forages and plant cell walls. Plant cell walls are linked and packed together in tight configurations to resist degradation, and hence their nutritional value to animals varies considerably, depending on composition, structure and degradability. An understanding of the inter-relationship between the chemical composition and the degradation of plant cell walls by rumen microorganisms is of major economic importance to ruminant production. Increasing the efficiency of fibre degradation in the rumen has been the subject of extensive research for many decades. This review summarises current knowledge of forage chemistry in order to develop strategies to increase efficiency of forage utilisation by ruminants.

Download Full-text

New Products Generated from the Transformations of Ferulic Acid Dilactone

Biomolecules ◽

10.3390/biom10020175 ◽

2020 ◽

Vol 10 (2) ◽

pp. 175 ◽

Cited By ~ 2

Author(s):

Ying He ◽

Yuan Jia ◽

Fachuang Lu

Keyword(s):

Ferulic Acid ◽

Succinic Acid ◽

Plant Cell ◽

Cell Walls ◽

New Products ◽

Plant Cell Walls ◽

Reaction Conditions ◽

Radical Coupling ◽

Naoh Treatment ◽

Derivatives Of

Various ferulic acid (FA) dimers occurring in plant cell walls, such as 8-5-, 8-O-4-, 5-5-, and 8-8-coupled dimers, are effective antioxidants and potential antimicrobials. It is necessary to access these diferulates as reference compounds to validate those isolated from plants. 3,6-bis(4-hydroxy-3-methoxyphenyl)-tetrahydrofuro-[3,4-c]furan-1,4-dione, a 8-8-coupled FA dilactone generated from ferulic acid via radical coupling, has been used to synthesize 8-8-coupled FA dimers although few reports investigated the distribution of products and mechanisms involved in the transformation of FA dilactone. In this work, the FA dilactone, obtained from FA by a peroxidase-catalyzed radical coupling, was reacted under various base/acid conditions. Effects of reaction conditions and workup procedures on the distribution of products were investigated by GC-MS. The isolated products from such treatments of FA dilactone were characterized by NMR. New derivatives of FA dimer including 2-(4-hydroxy-3-methoxybenzylidene)-3-(hydroxyl-(4-hydroxy-3-methoxyphenyl)methyl)succinic acid and 2-(bis(4-hydroxy-3-methoxyphenyl)-methyl)-succinic acid were produced from NaOH treatment. Another novel 8-8-coupled cyclic FA dimer, diethyl 6-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-7-methoxy-1,2-dihydronaphthalene-2,3-dicarboxylate was identified in products from FA dilactone treated by dry HCl in absolute ethanol. Mechanisms involved in such transformations were proposed.

Download Full-text

Plasmodesmata-Related Structural and Functional Proteins: The Long Sought-After Secrets of a Cytoplasmic Channel in Plant Cell Walls

International Journal of Molecular Sciences ◽

10.3390/ijms20122946 ◽

2019 ◽

Vol 20 (12) ◽

pp. 2946 ◽

Cited By ~ 7

Author(s):

Xiao Han ◽

Li-Jun Huang ◽

Dan Feng ◽

Wenhan Jiang ◽

Wenzhuo Miu ◽

...

Keyword(s):

Cell Wall ◽

Plant Cell ◽

Cell Walls ◽

Plasma Membranes ◽

Plant Cell Wall ◽

Plant Cells ◽

Protein Composition ◽

Cell Contact ◽

Plant Cell Walls ◽

Cell Organelles

Plant cells are separated by cellulose cell walls that impede direct cell-to-cell contact. In order to facilitate intercellular communication, plant cells develop unique cell-wall-spanning structures termed plasmodesmata (PD). PD are membranous channels that link the cytoplasm, plasma membranes, and endoplasmic reticulum of adjacent cells to provide cytoplasmic and membrane continuity for molecular trafficking. PD play important roles for the development and physiology of all plants. The structure and function of PD in the plant cell walls are highly dynamic and tightly regulated. Despite their importance, plasmodesmata are among the few plant cell organelles that remain poorly understood. The molecular properties of PD seem largely elusive or speculative. In this review, we firstly describe the general PD structure and its protein composition. We then discuss the recent progress in identification and characterization of PD-associated plant cell-wall proteins that regulate PD function, with particular emphasis on callose metabolizing and binding proteins, and protein kinases targeted to and around PD.

Download Full-text

Plant Cell Wall Changes in Common Wheat Roots as a Result of Their Interaction with Beneficial Fungi of Trichoderma

Cells ◽

10.3390/cells9102319 ◽

2020 ◽

Vol 9 (10) ◽

pp. 2319

Author(s):

Aneta Basińska-Barczak ◽

Lidia Błaszczyk ◽

Kinga Szentner

Keyword(s):

Cell Wall ◽

Common Wheat ◽

Plant Cell ◽

Plant Cell Wall ◽

Arabinogalactan Protein ◽

Plant Cell Walls ◽

Wheat Roots ◽

Wheat Seedlings ◽

Trichoderma Species ◽

Defense Strategies

Plant cell walls play an important role in shaping the defense strategies of plants. This research demonstrates the influence of two differentiators: the lifestyle and properties of the Trichoderma species on cell wall changes in common wheat seedlings. The methodologies used in this investigation include microscopy observations and immunodetection. In this study was shown that the plant cell wall was altered due to its interaction with Trichoderma. The accumulation of lignins and reorganization of pectin were observed. The immunocytochemistry indicated that low methyl-esterified pectins appeared in intercellular spaces. Moreover, it was found that the arabinogalactan protein epitope JIM14 can play a role in the interaction of wheat roots with both the tested Trichoderma strains. Nevertheless, we postulate that modifications, such as the appearance of lignins, rearrangement of low methyl-esterified pectins, and arabinogalactan proteins due to the interaction with Trichoderma show that tested strains can be potentially used in wheat seedlings protection to pathogens.

Download Full-text

Artificial plant cell walls as multi-catalyst systems for enzymatic cooperative asymmetric catalysis in non-aqueous media

Chemical Communications ◽

10.1039/d1cc02878b ◽

2021 ◽

Author(s):

Luca Deiana ◽

Abdolrahim Rafi ◽

Veluru Ramesh Naidu ◽

Cheuk-Wai Tai ◽

Jan-Erling Backvall ◽

...

Keyword(s):

Asymmetric Catalysis ◽

Plant Cell ◽

Cell Walls ◽

Plant Cell Wall ◽

Aqueous Media ◽

Cascade Reactions ◽

Plant Cell Walls ◽

Different Types ◽

Catalyst Systems ◽

Powerful Strategy

The assembly of cellulose-based artificial plant cell wall (APCW) structures that contain different types of catalysts, is a powerful strategy for the development of cascade reactions. Here we disclose an...

Download Full-text

Mechanisms Underlying the Rhizosphere-To-Rhizoplane Enrichment of Cellvibrio Unveiled by Genome-Centric Metagenomics and Metatranscriptomics

Microorganisms ◽

10.3390/microorganisms8040583 ◽

2020 ◽

Vol 8 (4) ◽

pp. 583

Author(s):

Yunzeng Zhang ◽

Jin Xu ◽

Entao Wang ◽

Nian Wang

Keyword(s):

Plant Cell ◽

Cell Walls ◽

Plant Cell Wall ◽

Iron Acquisition ◽

Root Surface ◽

Gene Gain ◽

Plant Cell Walls ◽

Genes Encoding ◽

Enhanced Expression ◽

Plant Cell Wall Degradation

Maintaining integrity of the plant cell walls is critical for plant health, however, our previous study showed that Cellvibrio, which is recognized by its robust ability to degrade plant cell walls, was enriched from the citrus rhizosphere to the rhizoplane (i.e., the root surface). Here we investigated the mechanisms underlying the rhizosphere-to-rhizoplane enrichment of Cellvibrio through genome-centric metagenomics and metatranscriptomics analyses. We recovered a near-complete metagenome-assembled genome representing a potentially novel species of Cellvibrio, herein designated Bin79, with genome size of 5.71 Mb across 11 scaffolds. Differential gene expression analysis demonstrated that plant cell wall degradation genes were repressed, whereas genes encoding chitin-degrading enzymes were induced in the rhizoplane compared with the rhizosphere. Enhanced expression of multi-drug efflux genes and iron acquisition- and storage-associated genes in the rhizoplane indicated mechanisms by which Bin79 competes with other microbes. In addition, genes involved in repelling plant immune responses were significantly activated in the rhizoplane. Comparative genomics analyses with five related Cellvibrio strains showed the importance of gene gain events for the rhizoplane adaptation of Bin79. Overall, this study characterizes a novel Cellvibrio strain and indicates the mechanisms involved in its adaptation to the rhizoplane from meta-omics data without cultivation.

Download Full-text

Redesigning plant cell walls for the biomass-based bioeconomy

Journal of Biological Chemistry ◽

10.1074/jbc.rev120.014561 ◽

2020 ◽

Vol 295 (44) ◽

pp. 15144-15157 ◽

Cited By ~ 2

Author(s):

Nicholas C. Carpita ◽

Maureen C. McCann

Keyword(s):

Lignocellulosic Biomass ◽

Plant Cell ◽

Cell Walls ◽

Plant Cell Wall ◽

Lignin Content ◽

Economic Value ◽

Structural Complexity ◽

The United States ◽

Plant Cell Walls ◽

Intrinsic Resistance

Lignocellulosic biomass—the lignin, cellulose, and hemicellulose that comprise major components of the plant cell well—is a sustainable resource that could be utilized in the United States to displace oil consumption from heavy vehicles, planes, and marine-going vessels and commodity chemicals. Biomass-derived sugars can also be supplied for microbial fermentative processing to fuels and chemicals or chemically deoxygenated to hydrocarbons. However, the economic value of biomass might be amplified by diversifying the range of target products that are synthesized in living plants. Genetic engineering of lignocellulosic biomass has previously focused on changing lignin content or composition to overcome recalcitrance, the intrinsic resistance of cell walls to deconstruction. New capabilities to remove lignin catalytically without denaturing the carbohydrate moiety have enabled the concept of the “lignin-first” biorefinery that includes high-value aromatic products. The structural complexity of plant cell-wall components also provides substrates for polymeric and functionalized target products, such as thermosets, thermoplastics, composites, cellulose nanocrystals, and nanofibers. With recent advances in the design of synthetic pathways, lignocellulosic biomass can be regarded as a substrate at various length scales for liquid hydrocarbon fuels, chemicals, and materials. In this review, we describe the architectures of plant cell walls and recent progress in overcoming recalcitrance and illustrate the potential for natural or engineered biomass to be used in the emerging bioeconomy.

Download Full-text