Tensional stress generation in gelatinous fibres: a review and possible mechanism based on cell-wall structure and composition
TL;DR: This review presents a model of gelatinous-fibre organization and stresses the unique character of the gelatinous layer as a separate type of cell-wall layer, different from either primary or secondary wall layers.
Abstract: Gelatinous fibres are specialized fibres, distinguished by the presence of an inner, gelatinous cell-wall layer. In recent years, they have attracted increasing interest since their walls have a desirable chemical composition (low lignin, low pentosan, and high cellulose contents) for applications such as saccharification and biofuel production, and they have interesting mechanical properties, being capable of generating high tensional stress. However, the unique character of gelatinous layer has not yet been widely recognized. The first part of this review presents a model of gelatinous-fibre organization and stresses the unique character of the gelatinous layer as a separate type of cell-wall layer, different from either primary or secondary wall layers. The second part discusses major current models of tensional stress generation by these fibres and presents a novel unifying model based on recent advances in knowledge of gelatinous wall structure. Understanding this mechanism could potentially lead to novel biomimetic developments in material sciences.
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TL;DR: In this paper, the main types of plant cell walls used as polymer reinforcements are discussed and the relationship between their structures and properties, in constant link with potential associated composite, is specifically discussed.
278 citations
TL;DR: The present review analyzes the dual property of plant cell walls, i.e., barrier and target of heavy metals, by taking Cd toxicity as example, and compares the wall-related mechanisms in early- and later-diverging land plants, by considering the diversity in cell wall composition.
Abstract: Increasing industrialization and urbanization result in emission of pollutants in the environment including toxic heavy metals, as cadmium and lead. Among the different heavy metals contaminating the environment, cadmium raises great concern, as it is ecotoxic and as such can heavily impact ecosystems. The cell wall is the first structure of plant cells to come in contact with heavy metals. Its composition, characterized by proteins, polysaccharides and in some instances lignin and other phenolic compounds, confers the ability to bind non-covalently and/or covalently heavy metals via functional groups. A strong body of evidence in the literature has shown the role of the cell wall in heavy metal response: it sequesters heavy metals, but at the same time its synthesis and composition can be severely affected. The present review analyzes the dual property of plant cell walls, i.e., barrier and target of heavy metals, by taking Cd toxicity as example. Following a summary of the known physiological and biochemical responses of plants to Cd, the review compares the wall-related mechanisms in early- and later-diverging land plants, by considering the diversity in cell wall composition. By doing so, common as well as unique response mechanisms to metal/cadmium toxicity are identified among plant phyla and discussed. After discussing the role of hyperaccumulators’ cell walls as a particular case, the review concludes by considering important aspects for plant engineering.
266 citations
Cites background from "Tensional stress generation in gela..."
...These cells are very long and known as bast fibers (Mellerowicz and Gorshkova, 2012; Guerriero et al., 2013)....
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TL;DR: An overview of the current knowledge concerning lignocellulosic biomass synthesis and degradation, by focusing on its three principal constituents, i.e. cellulose, hemicellulose (in particular xylan), and lignin is provided.
Abstract: Lignocellulose biomass derived from plant cell walls is a rich source of biopolymers, chemicals, and sugars, besides being a sustainable alternative to petrochemicals. A natural armor protecting living protoplasts, the cell wall is currently the target of intense study because of its crucial importance in plant development, morphogenesis, and resistance to (a)biotic stresses. Beyond the intrinsic relevance related to the overall plant physiology, plant cell walls constitute an exquisite example of a natural composite material that is a constant source of inspiration for biotechnology, biofuel, and biomaterial industries. The aim of the present review is to provide the reader with an overview of the current knowledge concerning lignocellulosic biomass synthesis and degradation, by focusing on its three principal constituents, i.e. cellulose, hemicellulose (in particular xylan), and lignin. Furthermore, the current industrial exploitation of lignocellulose from fast growing fibre crops (such as hemp) is highlighted. We conclude this review by suggesting approaches for further research to fill gaps in our current knowledge and to highlight the potential of biotechnology and bioengineering in improving both biomass biosynthesis and degradation.
170 citations
Cites background from "Tensional stress generation in gela..."
...An additional type of cell wall (more precisely a cell wall layer), called “gelatinous” (or G-layer) found in tension wood that is particularly rich in crystalline cellulose and poor in lignin [1] can be observed in response to mechanical stimuli, e....
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...These crops have gained a lot of interest in recent years because they represent a rapidly available source of lignocellulosic biomass where the presence of gelatinous fibres with low lignin content provides less hindrance to enzymatic hydrolysis [1]....
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TL;DR: High spatial resolution of the AspWood large-scale data set enabled identification of novel roles for characterized genes involved in xylan and cellulose biosynthesis, regulators of xylem vessel and fiber differentiation and lignification and regulation of the transcriptome underlying cambial growth and wood formation.
Abstract: Trees represent the largest terrestrial carbon sink and a renewable source of ligno-cellulose. There is significant scope for yield and quality improvement in these largely undomesticated species, ...
158 citations
Cites background from "Tensional stress generation in gela..."
...Primary Cell Wall Polysaccharide Biosynthetic Genes Continue to Be Expressed during Secondary Cell Wall Deposition in Xylem Tissues In Populus xylem, primary and secondary cell wall layers have very different polysaccharide compositions (Mellerowicz and Gorshkova, 2012)....
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...In Populus xylem, primary and secondary cell wall layers have very different polysaccharide compositions (Mellerowicz and Gorshkova, 2012)....
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...…terminated in long-lived cell types such as parenchyma cells or gelatinous-fibers in tensionwood, a subsequently deposited layer containing pectin and xyloglucan can be observed in these cells that resembles the PCW layer (Fujii et al., 1981; Murakami et al., 1999; Mellerowicz and Gorshkova, 2012)....
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...Indeed, when SCW deposition is terminated in long-lived cell types such as parenchyma cells or gelatinous-fibers in tensionwood, a subsequently deposited layer containing pectin and xyloglucan can be observed in these cells that resembles the PCW layer (Fujii et al., 1981; Murakami et al., 1999; Mellerowicz and Gorshkova, 2012)....
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TL;DR: A mini-review of recent results indicated that pectin influences secondary wall formation in addition to its roles in primary wall biosynthesis and modification is examined in the context of biomass yield and digestibility and how these traits might be enhanced by the genetic and molecular modification of pectIn.
Abstract: Pectin is a component of the cell walls of plants that is composed of acidic sugar-containing backbones with neutral sugar-containing side chains. It functions in cell adhesion and wall hydration, and pectin crosslinking influences wall porosity and plant morphogenesis. Despite its low abundance in the secondary cell walls that make up the majority of lignocellulosic biomass, recent results have indicated that pectin influences secondary wall formation in addition to its roles in primary wall biosynthesis and modification. This mini-review will examine these and other recent results in the context of biomass yield and digestibility and discuss how these traits might be enhanced by the genetic and molecular modification of pectin. The utility of pectin as a high-value, renewable biomass co-product will also be highlighted.
125 citations
Cites background from "Tensional stress generation in gela..."
...Pectinassociated β-1,4-galactans have also been detected in the secondary walls of tension and compression wood (Mellerowicz and Gorshkova, 2012), and upregulation of both pectin-modifying and secondary wall biosynthetic genes has been detected in Arabidopsis plants placed under mechanical load…...
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References
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TL;DR: In this article, the present status of the chemistry of wood hemicelluloses is summarized, with special emphasis on recent contributions, and problems still to be solved in wood chemistry are discussed, and an attempt is made to predict future developments in this field.
Abstract: Following a brief review of the general chemical composition of wood, the present status of the chemistry of the wood hemicelluloses is summarized, with special emphasis on recent contributions. The distribution of the hemicelluloses in the various wood tissues and wood cells and over the cell wall of tracheids and fibers is discussed in somewhat more detail. In conclusion, problems still to be solved in the chemistry of wood hemicelluloses are mentioned, and an attempt is made to predict future developments in this field.
813 citations
TL;DR: Wood is the most important natural and endlessly renewable source of energy and therefore has a major future role as an environmentally cost-effective alternative to burning fossils fuels.
Abstract: Among the ecosystem services provided by forests, wood provisioning takes a central position. Wood and derived products have played a critical role in the evolution of human kind and demand for raw material is increasing in a foreseeable future. Wood is used for energy production, construction and a wide variety of products for which different properties are required. Anatomical, chemical and physical properties of wood are determined through a complex process called xylogenesis controlled by internal and external signals and occurring during the life of the tree. In this chapter we describe i/how wood is formed and ii/the different factors controlling this developmental process with emphasis on the molecular machinery involved, iii/the functions of wood and iv/the biotechnology approaches developed to improve wood biomass production and properties genetically.
678 citations
Book•
04 Feb 2011
TL;DR: With the exception of sem D, the spatiotemporal expression of the secreted semaphorins, in particular H-sema IV, is not well defined, limiting the correlation with the expression pattern of their putative receptors.
Abstract: Since the semaphorins were first identified in grasshopper and independently in chicken, these proteins have been found in all metazoa examined.1–3 The semaphorin family consists of both secreted and cell-surface molecules, which share a conserved domain of ~500 amino acids, the semaphorin domain.4 Additionally, some of the semaphorins contain an immunoglobulin domain or a stretch of thrombospondin repeats.1,3–6 Several secreted semaphorins (sem A, sem D, sem E and M-sem H) have been cloned in mouse.3,7 The best studied vertebrate semaphorin is Sem D and its respective homologues from chicken and human, termed collapsin-1 and sema III, respectively.1,4 Collapsin-1 was isolated and cloned by its activity to induce growth come collapse of sensory axons from dorsal root ganglia (DRG).1 Collapsin-1 and sem D/sema III (hereafter referred to as sem D) have also been shown to act as a chemorepellent for sensory and motor axon s in vitr o.3,8–11 Messersmit h et a l. showed that in cultured rat DRG (E14), the nerve growth factor (NGF)responsive neurons, but not the neurotrophin 3 (NT-3)-responsive neurons, are repelled by sem D suggesting that different neuronal subpopulations might respond to other semaphorins.9 Recently, three groups cloned a human semaphorin as a candidate tumor suppressor gene by positional cloning.12–14 This semaphorin, terme d H-sema III/ F or H-sema IV (hereafter referred to a s H-sema IV ), resides in a region of chromosome 3 (3p21.3), which is deleted in almost 100% of small cell lung cancers (SCLC).15–18 So far, however, attempts to find mutations o f H-sema IV associated with SCLC have failed.12–14 A first step to understand the mechanisms of action of semaphorins was the identification of neuropilin1 as a receptor or part of a receptor complex for sem D.19,20 Binding to neuropilin-1 seems to be conferred by both the semaphorin domain and the positively charged carboxyterminus.20–22 In cell culture, several semaphorins bind neuropilin-1 with comparable affinity.22,23 However, labelling studies on tissue sections using tagged semaphorin proteins suggest that the semaphorin domain encodes specificity for bindin g in sit u.22 Recently, a novel member of the neuropilin family, termed neuropilin-2, has been found to be a high affinity receptor for sem E and H-sema IV but not for sem D in vitr o.19,23 With the exception of sem D, the spatiotemporal expression of the secreted semaphorins, in particular H-sema IV, is not well defined, limiting the correlation with the expression pattern of their putative receptors.
545 citations
"Tensional stress generation in gela..." refers background in this paper
...Xylan, the main non-cellulosic polysaccharide of S-layers, has been shown to be absent in G-layers of gelatinous fibres (in several plant species) by immunocytochemical analysis, using anti-xylan antibodies that heavily label S-layers but do not reportedly bind to G-layers (Bowling and Vaughn, 2008; Decou et al., 2009)....
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...…polysaccharide of S-layers, has been shown to be absent in G-layers of gelatinous fibres (in several plant species) by immunocytochemical analysis, using anti-xylan antibodies that heavily label S-layers but do not reportedly bind to G-layers (Bowling and Vaughn, 2008; Decou et al., 2009)....
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TL;DR: A new molecular model consisting of a 36-glucan-chain elementary fibril, in which the 36- glucan chains form both crystalline and subcrystalline structures is proposed based on recently reported experimental evidence from plant cell wall biosynthesis.
Abstract: Understanding the molecular architecture of the plant cell wall is critical to reducing the biomass recalcitrance problem, which currently impedes economic bioconversion processing. The parenchyma cell walls from field senesced, maize stem pith have been directly visualized without extraction processes using high-resolution atomic force microscopy (AFM). By imaging the cell wall inner surfaces from different cells and different faces of the same cell, we were able to map the native primary cell wall ultrastructures. Depending on the thickness of non-cellulosic deposition, the parallel-microfibrils appear in various morphologies ranging from clearly defined to completely embedded in the wall matrixes forming cell wall lamella. Macrofibrils were found to exist only on the uppermost layer of the native primary cell wall and appeared to be bundles of elementary fibrils. This novel observation led us to a new hypothesis for the cell wall fibrillar network and biosynthesis processes. Put concisely, a number of elementary fibrils are synthesized at one locus, that of the cellulose synthase complex (CelS), and coalesce into much larger macrofibrils. These macrofibrils eventually split at the ends to form parallel microfibrils with deposition of other cell wall components (i.e. hemicelluloses, pectin, etc.) also evident. On the basis of these AFM surface measurements and current supportive evidence from cell wall biophysics, biosynthesis, and genomics, we propose a new molecular model consisting of a 36-glucan-chain elementary fibril, in which the 36-glucan chains form both crystalline and subcrystalline structures. We also propose a modified model of CelS based on recently reported experimental evidence from plant cell wall biosynthesis.
521 citations