scholarly journals The Cytoskeleton and Its Role in Determining Cellulose Microfibril Angle in Secondary Cell Walls of Woody Tree Species

Plants ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 90
Author(s):  
Tobias ◽  
Spokevicius ◽  
McFarlane ◽  
Bossinger
Keyword(s):  
Molecular Mechanisms ◽  
Cellulose Microfibril ◽  
Wood Quality ◽  
Microfibril Angle ◽  
Wood Formation ◽  
Cellulose Microfibrils ◽  
Reaction Wood ◽  
Molecular Control ◽  
Cellulose Deposition ◽  
Cellulose Microfibril Angle

Recent advances in our understanding of the molecular control of secondary cell wall (SCW) formation have shed light on molecular mechanisms that underpin domestication traits related to wood formation. One such trait is the cellulose microfibril angle (MFA), an important wood quality determinant that varies along tree developmental phases and in response to gravitational stimulus. The cytoskeleton, mainly composed of microtubules and actin filaments, collectively contribute to plant growth and development by participating in several cellular processes, including cellulose deposition. Studies in Arabidopsis have significantly aided our understanding of the roles of microtubules in xylem cell development during which correct SCW deposition and patterning are essential to provide structural support and allow for water transport. In contrast, studies relating to SCW formation in xylary elements performed in woody trees remain elusive. In combination, the data reviewed here suggest that the cytoskeleton plays important roles in determining the exact sites of cellulose deposition, overall SCW patterning and more specifically, the alignment and orientation of cellulose microfibrils. By relating the reviewed evidence to the process of wood formation, we present a model of microtubule participation in determining MFA in woody trees forming reaction wood (RW).

scholarly journals Xyloglucan Is Not Essential for the Formation and Integrity of the Cellulose Network in the Primary Cell Wall Regenerated from Arabidopsis Protoplasts

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 629 ◽  
Author(s):  
Hiroaki Kuki ◽  
Ryusuke Yokoyama ◽  
Takeshi Kuroha ◽  
Kazuhiko Nishitani
Keyword(s):  
Cell Wall ◽  
Cellulose Microfibril ◽  
Mechanical Stability ◽  
Molecular Model ◽  
Primary Cell ◽  
Cellulose Microfibrils ◽  
Primary Cell Wall ◽  
Imaging Analysis ◽  
Cellulose Deposition ◽  
Initial Assembly

The notion that xyloglucans (XG) play a pivotal role in tethering cellulose microfibrils in the primary cell wall of plants can be traced back to the first molecular model of the cell wall proposed in 1973, which was reinforced in the 1990s by the identification of Xyloglucan Endotransglucosylase/Hydrolase (XTH) enzymes that cleave and reconnect xyloglucan crosslinks in the cell wall. However, this tethered network model has been seriously challenged since 2008 by the identification of the Arabidopsis thaliana xyloglucan-deficient mutant (xxt1 xxt2), which exhibits functional cell walls. Thus, the molecular mechanism underlying the physical integration of cellulose microfibrils into the cell wall remains controversial. To resolve this dilemma, we investigated the cell wall regeneration process using mesophyll protoplasts derived from xxt1 xxt2 mutant leaves. Imaging analysis revealed only a slight difference in the structure of cellulose microfibril network between xxt1 xxt2 and wild-type (WT) protoplasts. Additionally, exogenous xyloglucan application did not alter the cellulose deposition patterns or mechanical stability of xxt1 xxt2 mutant protoplasts. These results indicate that xyloglucan is not essential for the initial assembly of the cellulose network, and the cellulose network formed in the absence of xyloglucan provides sufficient tensile strength to the primary cell wall regenerated from protoplasts.

Cellulose microfibril orientation in Oocystis solitaria: proof that microtubules control the alignment of the terminal complexes

1986 ◽  
Vol 83 (1) ◽  
pp. 223-234
Author(s):  
H. Quader
Keyword(s):  
Cellulose Microfibril ◽  
Drug Application ◽  
Freeze Fracture ◽  
Cellulose Microfibrils ◽  
Cortical Microtubules ◽  
Terminal Complex ◽  
Experimental Proof ◽  
Cellulose Deposition ◽  
Cellulose Microfibril Orientation ◽  
Terminal Complexes

In the green alga Oocystis solitaria microtubules control the regular deposition of cellulose microfibrils. Although it has frequently been suggested that the influence of the cortical microtubules is mediated through the alignment of structures in the plasma membrane, e.g. the cellulose-synthesizing enzymes, experimental proof is lacking. In Oocystis the putative cellulose-synthesizing units, the so-called terminal complexes, can be visualized following freeze-fracture. With respect to the synthesis of a given layer of microfibrils two distinct situations are observable: terminal complex doublets occur before the start of cellulose formation, but are subsequently separated into single terminal complexes by pressure exerted by the crystallizing microfibrils. In order to investigate the effect of anti-microtubular substances on the orientation of the terminal complexes, the state of cellulose deposition at the time of drug application was marked by short (15–30 min) treatment with Congo Red, which causes a morphological change in the terminal complexes. The characteristic alignment of the terminal complexes, both doublets and fragmented single ones, is severely disturbed in cells treated with the herbicide amiprophosmethyl, which is known to interfere with the action of microtubules. The results provide strong evidence that microtubules control the alignment of the putative cellulose-forming units in Oocystis. The observed pattern of interference indicates that the microtubules most probably achieve their control by imposing fluidity channels on the membrane and not via direct links with the terminal complexes.

scholarly journals Transcriptome and microRNA Sequencing Identified miRNAs and Target Genes in Different Developmental Stages of the Vascular Cambium in Cryptomeria fortunei Hooibrenk

2021 ◽  
Vol 12 ◽  
Author(s):  
Hailiang Hu ◽  
Zhenhao Guo ◽  
Junjie Yang ◽  
Jiebing Cui ◽  
Yingting Zhang ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Target Genes ◽  
Developmental Stages ◽  
Wood Quality ◽  
Tree Breeding ◽  
Wood Formation ◽  
Cellular Growth ◽  
Vascular Cambium ◽  
Timber Species ◽  
Illumina Hiseq

Cryptomeria fortunei Hooibrenk is an important fast-growing coniferous timber species that is widely used in landscaping. Recently, research on timber quality has gained substantial attention in the field of tree breeding. Wood is the secondary xylem formed by the continuous inward division and differentiation of the vascular cambium; therefore, the development of the vascular cambium is particularly important for wood quality. In this study, we analyzed the transcriptomes of the cambial zone in C. fortunei during different developmental stages using Illumina HiSeq sequencing, focusing on general transcriptome and microRNA (miRNA) data. We performed functional annotation of the differentially expressed genes (DEGs) in the different stages identified by transcriptome sequencing and generated 15 miRNA libraries yielding 4.73 Gb of clean reads. The most common length of the filtered miRNAs was 21nt, accounting for 33.1% of the total filtered reads. We annotated a total of 32 known miRNA families. Some miRNAs played roles in hormone signal transduction (miR159, miR160, and miR166), growth and development (miR166 and miR396), and the coercion response (miR394 and miR395), and degradome sequencing showed potential cleavage sites between miRNAs and target genes. Differential expression of miRNAs and target genes and functional validation of the obtained transcriptome and miRNA data provide a theoretical basis for further elucidating the molecular mechanisms of cellular growth and differentiation, as well as wood formation in the vascular cambium, which will help improve the wood quality of C. fortunei.

scholarly journals Erratum: The Cytoskeleton and Its Role in Determining Cellulose Microfibril Angle in Secondary Cell Walls of Woody Tree Species. Plants 2020, 9, 90.

Plants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 255
Author(s):  
Keyword(s):  
Tree Species ◽  
Cell Walls ◽  
Cellulose Microfibril ◽  
Microfibril Angle ◽  
Editorial Office ◽  
Secondary Cell Walls ◽  
Cellulose Microfibril Angle

The Editorial Office of Plants wants to make the following corrections to the paper by Tobias, L.M., et al. (2020)[...]

Cellulose microfibril angle variation in Picea crassifolia tree rings improves climate signals on the Tibetan plateau

Trees ◽  
2012 ◽  
Vol 26 (3) ◽  
pp. 1007-1016 ◽  
Author(s):  
Jinmei Xu ◽  
Jianxiong Lu ◽  
Fucheng Bao ◽  
Robert Evans ◽  
Geoffrey Downes ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Tree Rings ◽  
Cellulose Microfibril ◽  
Microfibril Angle ◽  
The Tibetan Plateau ◽  
Angle Variation ◽  
Picea Crassifolia ◽  
Climate Signals ◽  
Cellulose Microfibril Angle
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