Cellulose Synthesis Research Articles

Research Progress of Gramineae Cellulose Synthase Gene in Cellulose Synthesis Regulation

Research Progress of Gramineae Cellulose Synthase Gene in Cellulose Synthesis Regulation

Cortical tension overrides geometrical cues to orient microtubules in confined protoplasts

In plant cells, cortical microtubules (CMTs) generally control morphogenesis by guiding cellulose synthesis. CMT alignment has been proposed to depend on geometrical cues, with microtubules aligning with the cell long axis in silico and in vitro. Yet, CMTs are usually transverse in vivo, i.e., along predicted maximal tension, which is transverse for cylindrical pressurized vessels. Here, we adapted a microwell setup to test these predictions in a single-cell system. We confined protoplasts laterally to impose a curvature ratio and modulated pressurization through osmotic changes. We find that CMTs can be longitudinal or transverse in wallless protoplasts and that the switch in CMT orientation depends on pressurization. In particular, longitudinal CMTs become transverse when cortical tension increases. This explains the dual behavior of CMTs in planta: CMTs become longitudinal when stress levels become low, while stable transverse CMT alignments in tissues result from their autonomous response to tensile stress fluctuations.

Identification of the Clostridial cellulose synthase and characterization of the cognate glycosyl hydrolase, CcsZ.

Biofilms are community structures of bacteria enmeshed in a self-produced matrix of exopolysaccharides. The biofilm matrix serves numerous roles, including resilience and persistence, making biofilms a subject of research interest among persistent clinical pathogens of global health importance. Our current understanding of the underlying biochemical pathways responsible for biosynthesis of these exopolysaccharides is largely limited to Gram-negative bacteria. Clostridia are a class of Gram-positive, anaerobic and spore-forming bacteria and include the important human pathogens Clostridium perfringens, Clostridium botulinum and Clostridioides difficile, among numerous others. Several species of Clostridia have been reported to produce a biofilm matrix that contains an acetylated glucan linked to a series of hypothetical genes. Here, we propose a model for the function of these hypothetical genes, which, using homology modelling, we show plausibly encode a synthase complex responsible for polymerization, modification and export of an O-acetylated cellulose exopolysaccharide. Specifically, the cellulose synthase is homologous to that of the known exopolysaccharide synthases in Gram-negative bacteria. The remaining proteins represent a mosaic of evolutionary lineages that differ from the described Gram-negative cellulose exopolysaccharide synthases, but their predicted functions satisfy all criteria required for a functional cellulose synthase operon. Accordingly, we named these hypothetical genes ccsZABHI, for the Clostridial cellulose synthase (Ccs), in keeping with naming conventions for exopolysaccharide synthase subunits and to distinguish it from the Gram-negative Bcs locus with which it shares only a single one-to-one ortholog. To test our model and assess the identity of the exopolysaccharide, we subcloned the putative glycoside hydrolase encoded by ccsZ and solved the X-ray crystal structure of both apo- and product-bound CcsZ, which belongs to glycoside hydrolase family 5 (GH-5). Although not homologous to the Gram-negative cellulose synthase, which instead encodes the structurally distinct BcsZ belonging to GH-8, we show CcsZ displays specificity for cellulosic materials. This specificity of the synthase-associated glycosyl hydrolase validates our proposal that these hypothetical genes are responsible for biosynthesis of a cellulose exopolysaccharide. The data we present here allowed us to propose a model for Clostridial cellulose synthesis and serves as an entry point to an understanding of cellulose biofilm formation among class Clostridia.

Synthesis and characterization of hydroxyethyl cellulose (HEC)-TiO2-based polyurethane bionanocomposites

A novel green series of hydroxyethyl cellulose (HEC) based polyurethane (PUs) prepolymersblended with TiO2 nanoparticles were synthesized by reaction of Isophorone diisocyanate (IPDI), hydroxyl-terminated polybutadiene (HTPB), and hydroxyethyl cellulose (HEC). The chain was further extended with 1,4-butanediol (BDO) to get final HEC based polyurethane bio nanocomposites (FPUNC). A mixture of HEC based polymer and TiO2 nanoparticles was formed in solution polymerization, in which the TiO2 nanoparticles dispersed depending on interaction of TiO2 nanoparticles with polymer chains. The molecular structure of the synthesized PU bionanocomposites was confirmed by FTIR. A series of FPUNCs was prepared by varying the percent composition of the TiO2 nanoparticles into the PU matrix. The morphology of the bionanocomposites was carried out by X-ray diffraction (XRD) studies and scanning electron microscopy (SEM). SEM images verified the good dispersion of TiO2 nanoparticles into PU matrix. The thermal stability of the synthesized FPUNCs was done by thermal gravimetric analysis (TGA), and the FPUNC12 with 5% contents of TiO2 nanoparticles showed better thermal stability. The resultant HEC-TiO2 based FPUNCs material have promising bio-degradable and bio functional materials with good thermal properties and have potential applications in the field of biomaterials.

Tissue-specific Transcriptome analysis reveals lignocellulose synthesis regulation in elephant grass (Pennisetum purpureum Schum)

BackgroundThe characteristics of elephant grass, especially its stem lignocellulose, are of great significance for its quality as feed or other industrial raw materials. However, the research on lignocellulose biosynthesis pathway and key genes is limited because the genome of elephant grass has not been deciphered.ResultsIn this study, RNA sequencing (RNA-seq) combined with lignocellulose content analysis and cell wall morphology observation using elephant grass stems from different development stages as materials were applied to reveal the genes that regulate the synthesis of cellulose and lignin. A total of 3852 differentially expressed genes (DEGs) were identified in three periods of T1, T2, and T3 through RNA-seq analysis. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of all DEGs showed that the two most abundant metabolic pathways were phenylpropane metabolism, starch and sucrose metabolism, which were closely related to cell wall development, hemicellulose, lignin and cellulose synthesis. Through weighted gene co-expression network analysis (WGCNA) of DEGs, a ‘blue’ module highly associated with cellulose synthesis and a ‘turquoise’ module highly correlated with lignin synthesis were exhibited. A total of 43 candidate genes were screened, of which 17 had function annotations in other species. Besides, by analyzing the content of lignocellulose in the stem tissues of elephant grass at different developmental stages and the expression levels of genes such as CesA, PAL, CAD, C4H, COMT, CCoAMT, F5H and CCR, it was found that the content of lignocellulose was related to the expression level of these structural genes.ConclusionsThis study provides a basis for further understanding the molecular mechanisms of cellulose and lignin synthesis pathways of elephant grass, and offers a unique and extensive list of candidate genes for future specialized functional studies which may promote the development of high-quality elephant grass varieties with high cellulose and low lignin content.

Sticking to seeds: direct regulation of cellulose synthesis controls seed mucilage development.

Sticking to seeds: direct regulation of cellulose synthesis controls seed mucilage development.

Disruption of Very-Long-Chain-Fatty Acid Synthesis Has an Impact on the Dynamics of Cellulose Synthase in Arabidopsis thaliana.

In higher plants, cellulose is synthesized by membrane-spanning large protein complexes named cellulose synthase complexes (CSCs). In this study, the Arabidopsis PASTICCINO2 (PAS2) was identified as an interacting partner of cellulose synthases. PAS2 was previously characterized as the plant 3-hydroxy-acyl-CoA dehydratase, an ER membrane-localized dehydratase that is essential for very-long-chain-fatty acid (VLCFA) elongation. The pas2-1 mutants show defective cell elongation and reduction in cellulose content in both etiolated hypocotyls and light-grown roots. Although disruption of VLCFA synthesis by a genetic alteration had a reduction in VLCFA in both etiolated hypocotyls and light-grown roots, it had a differential effect on cellulose content in the two systems, suggesting the threshold level of VLCFA for efficient cellulose synthesis may be different in the two biological systems. pas2-1 had a reduction in both CSC delivery rate and CSC velocity at the PM in etiolated hypocotyls. Interestingly, Golgi but not post-Golgi endomembrane structures exhibited a severe defect in motility. Experiments using pharmacological perturbation of VLCFA content in etiolated hypocotyls strongly indicate a novel function of PAS2 in the regulation of CSC and Golgi motility. Through a combination of genetic, biochemical and cell biology studies, our study demonstrated that PAS2 as a multifunction protein has an important role in the regulation of cellulose biosynthesis in Arabidopsis hypocotyl.

Overexpression of a Sucrose Synthase Gene Indirectly Improves Cotton Fiber Quality Through Sucrose Cleavage.

The study aims to improve fiber traits of local cotton cultivar through genetic transformation of sucrose synthase (SuS) gene in cotton. Sucrose synthase (SuS) is an important factor that is involved in the conversion of sucrose to fructose and UDP-glucose, which are essential for the synthesis of cell wall cellulose. In the current study, we expressed a synthetic SuS gene in cotton plants under the control of a CaMV35S promoter. Amplification of an 813-bp fragment using gene-specific primers confirmed the successful introduction of SuS gene into the genome of cotton variety CEMB-00. High SuS mRNA expression was observed in two transgenic cotton plants, MA0023 and MA0034, when compared to the expression in two other transgenic cotton plants, MA0035 and MA0038. Experiments showed that SuS mRNA expression was positively correlated with SuS activity at the vegetative (54%) and reproductive stages (40%). Furthermore, location of transgene was found to be at chromosome no. 9 in the form of single insertion, while no signal was evident in non-transgenic control cotton plant when evaluated through fluorescent in situ hybridization and karyotyping analysis. Fiber analyses of the transgenic cotton plants showed increases of 11.7% fiber length, 18.65% fiber strength, and up to 5% cellulose contents. An improvement in the micronaire value of 4.21 was also observed in the MA0038 transgenic cotton line. Scanning electron microscopy (SEM) revealed that the fibers of the SuS transgenic cotton plants were highly spiral with a greater number of twists per unit length than the fibers of the non-transgenic control plants. These results determined that SuS gene expression influenced cotton fiber structure and quality, suggesting that SuS gene has great potential for cotton fiber quality improvement.

Auxin Directly Upregulates GhRAC13 Expression to Promote the Onset of Secondary Cell Wall Deposition in Cotton Fibers.

Cotton fibers are single cells that show a relatively independent developmental process of cell differentiation, elongation, and secondary wall deposition. Auxin promotes fiber cell protrusion from the surface of the ovule. However, the role of auxin at other stages of cotton fiber development remains largely unknown. To gain a deeper insight into this aspect, we measured indoleacetic acid (IAA) content in developing fibers. Results showed an increase in IAA content at the transition stage from elongation to secondary cell wall deposition. Subsequently, we investigated the differences between two transgenic cottons that show upregulated and downregulated fiber auxin levels, respectively. In planta analysis revealed that, in addition to promoting cell elongation, auxin regulated the time of initiation of reactive oxygen species (ROS) production and secondary wall deposition in cotton fibers. This was closely correlated with the upregulated expression of GhRAC13, which regulates ROS-triggered cellulose synthesis. We found multiple putative auxin-responsive elements existed within the promoter region of GhRAC13, and IAA could induce proGhRAC13 activity. The dual-luciferase reporter assay further proved the activation of proGhRAC13 by GhARF5, an auxin-signaling activator. Altogether, our results suggest a role of auxin in promoting the onset of secondary growth by directly upregulating GhRAC13 expression in cotton fibers.

Low And Highly Substituted Carboxymethyl Cellulose Synthesis From Powdered And Microcrystalline Cellulose

The conditions for low and highly substituted water-soluble carboxymethyl cellulose synthesis based on microcrystalline and powder cellulose by the suspension method have been investigated. Accordingly, it was obtained CMC water-soluble samples with 0.38-0.40 substitution degree based on microcrystalline and powder cellulose. And at one stage, there were obtained CMC samples with a high degree of substitution (1.4) by carboxymethylation so called polyanionic cellulose.

Enhanced Activity of Genes Associated With Photosynthesis, Phytohormone Metabolism and Cell Wall Synthesis Is Involved in Gibberellin-Mediated Sugarcane Internode Growth.

Internode elongation is an important trait in sugarcane as it affects the sugarcane yield. Gibberellin (GA) is a key modulator of internode elongation in sugarcane. Understanding the gene expression features of GA-mediated internode elongation has both scientific and practical significance. This study aimed to examine the transcriptomic changes in the internode elongation of sugarcane following GA treatment. Eighteen cDNA libraries from the internode tissues on days of 0, 3, and 6 in control and GA treatment groups were sequenced and their gene expression were studied. RNA-seq analysis revealed 1,338,723,248 reads and 70,821 unigenes from elongating internodes of sugarcane. Comparative studies discovered a large number of transcripts that were differentially expressed in GA-treated samples compared to the control. Further analysis revealed that the differentially expressed genes were enriched in the metabolic process, one-carbon compound transport, and single-organism process. Kyoto Encyclopedia of Genes and Genomes pathway annotation showed significant enrichment in photosynthesis and plant hormone signal transduction, indicating its involvement in internode elongation. The function analysis suggested that metabolic pathways and biosynthesis of secondary metabolites, plant hormones, and cell wall components were enriched in the internodes of the GA-treated plants. The hub genes were identified, with the function of cellulose synthesis. The results of this study provide a global view of mRNA changes during sugarcane internode elongation and extend our knowledge of the GA-mediated cellular processes involved in sugarcane stem growth.

Overexpression of PtrMYB121 Positively Regulates the Formation of Secondary Cell Wall in Arabidopsis thaliana

MYB transcription factors have a wide range of functions in plant growth, hormone signaling, salt, and drought tolerances. In this study, two homologous transcription factors, PtrMYB55 and PtrMYB121, were isolated and their functions were elucidated. Tissue expression analysis revealed that PtrMYB55 and PtrMYB121 had a similar expression pattern, which had the highest expression in stems. Their expression continuously increased with the growth of poplar, and the expression of PtrMYB121 was significantly upregulated in the process. The full length of PtrMYB121 was 1395 bp, and encoded protein contained 464 amino acids including conserved R2 and R3 MYB domains. We overexpressed PtrMYB121 in Arabidopsis thaliana, and the transgenic lines had the wider xylem as compared with wild-type Arabidopsis. The contents of cellulose and lignin were obviously higher than those in wild-type materials, but there was no significant change in hemicellulose. Quantitative real-time PCR demonstrated that the key enzyme genes regulating the synthesis of lignin and cellulose were significantly upregulated in the transgenic lines. Furthermore, the effector-reporter experiment confirmed that PtrMYB121 bound directly to the promoters of genes relating to the synthesis of lignin and cellulose. These results suggest that PtrMYB121 may positively regulate the formation of secondary cell wall by promoting the synthesis of lignin and cellulose.

MYB61 is regulated by GRF4 and promotes nitrogen utilization and biomass production in rice

Nitrogen (N) is a macronutrient that boosts carbon (C) metabolism and plant growth leading to biomass accumulation. The molecular connection between nitrogen utilization efficiency (NUE) and biomass production remains unclear. Here, via quantitative trait loci analysis and map-based cloning, we reveal that natural variation at the MYB61 locus leads to differences in N use and cellulose biogenesis between indica and japonica subspecies of rice. MYB61, a transcriptional factor that regulates cellulose synthesis, is directly regulated by a known NUE regulator GROWTH-REGULATING FACTOR4 (GRF4), which coordinates cellulosic biomass production and N utilization. The variation at MYB61 has been selected during indica and japonica domestication. The indica allele of MYB61 displays robust transcription resulting in higher NUE and increased grain yield at reduced N supply than that of japonica. Our study hence unravels how C metabolism is linked to N uptake and may provide an opportunity to reduce N use for sustainable agriculture.

Synthesis and Characterization of Superabsorbent Cellulose‐Based Hydrogel for Agriculture Application

AbstractHydrogels are 3D network formed by linear (or branched) hydrophilic polymer molecules that are chemically or physically crosslinked. Hydrogels can absorb a prominent amount of water and biological fluids and release them at a controlled rate. This study deals with the synthesis and characterization of carboxymethylcellulose sodium salt (CMCNa) and hydroxyethyl cellulose (HEC)‐based biodegradable hydrogels using citric acid (CA) as a crosslinker. The chemical analysis of synthesized hydrogels is performed using Fourier transform infrared spectroscopy. The cellulose nanocrystals (CNCs) are synthesized by an acid hydrolysis process and are incorporated into the hydrogel matrix and the effects of CNCs on hydrogel properties are assessed. The effects of the CA on hydrogels swelling properties are also studied and about 600% swelling is observed for the hydrogel synthesized using 2% of the CA crosslinker. Using CNCs as reinforcing agents for hydrogel composites decreases the tensile strength of hydrogels because of poor CNC dispersion within the hydrogel matrix is observed that can be seen in the scanning electron microscope images. The optimum use of crosslinkers and proper distribution of CNCs in the hydrogel matrix can provide a promising hydrogel material that can absorb and release water in a controlled manner to improve utilization of available water resources for agricultural applications.

A novel amino cellulose derivative using ATRP method: Preparation, characterization, and investigation of its antibacterial activity

In this study, we prepared a novel amino cellulose derivative (benzyl cellulose-g-poly [2-(N,N-Dimethylamino)ethyl methacrylate]) via a homogeneous ATRP method. The successful synthesis of the novel amino cellulose was confirmed by FT-IR and 1H NMR. This study addressed the different characteristics of the prepared polymer including the thermal stability, solubility, and X-ray diffraction pattern. The antibacterial activity of the synthesized cellulose derivative was investigated using the diffusion disk method against both gram-negative (Escherichia coli, Salmonella enterica) and gram-positive (Staphylococcus aureus, Bacillus subtilis) bacteria. Based on the inhibition zone, it was confirmed that the prepared benzyl cellulose-g-PDMAEMA possesses acceptable antibacterial activity against Escherichia coli, Salmonella enterica, and Staphylococcus aureus while Bacillus subtilis is resistant to the prepared polymer. Also according to the inhibition zone, it was shown that benzyl cellulose-g-PDMAEMA has more impact on E. coli and Salmonella enterica than Staphylococcus aureus. Molecular dynamics simulation was also used to study the interaction of the synthesized cellulose derivative with a model membrane which presented atomistic details of the polymer-lipid interactions. According to the results obtained from the molecular dynamics simulation, the polymer was able to destabilize the structure of the membrane and clearly express its signs of degradation.

Enhanced Chlorophyll Degradation Triggers the Pod Degreening of "Golden Hook," a Special Ecotype in Common Bean (Phaseolus vulgaris L.).

To reveal genetic factors or pathways involved in the pod degreening, we performed transcriptome and metabolome analyses using a yellow pod cultivar of the common bean “golden hook” ecotype and its green pod mutants yielded via gamma radiation. Transcriptional profiling showed that expression levels of red chlorophyll catabolite reductase (RCCR, Phvul.008G280300) involved in chlorophyll degradation was strongly enhanced at an early stage (2 cm long) in wild type but not in green pod mutants. The expression levels of genes involved in cellulose synthesis was inhibited by the pod degreening. Metabolomic profiling showed that the content of most flavonoid, flavones, and isoflavonoid was decreased during pod development, but the content of afzelechin, taxifolin, dihydrokaempferol, and cyanidin 3-O-rutinoside was remarkably increased in both wild type and green pod mutant. This study revealed that the pod degreening of the golden hook resulting from chlorophyll degradation could trigger changes in cellulose and flavonoids biosynthesis pathway, offering this cultivar a special color appearance and good flavor.

Synthesis of tannin-immobilized cellulose and its adsorption properties for berberine hydrochloride

Tannin-immobilized cellulose was prepared by the phenolic reaction of the phenol ring of tannin with the aldehyde group of aldocellulose, where aldocellulose was prepared by the oxidization of cellulose with sodium periodate as oxidizing agent. The method of immobilized tannin is environmentally friendly due to the lack of crosslinking agent. The adsorption properties of cellulose were improved due to the introduction of tannin. The maximum adsorption capacity of the tannin-immobilized cellulose for berberine hydrochloride was 143.66 mg/g. The isothermal adsorption for berberine hydrochloride conformed to the Langmuir model well. The adsorption of tannin-immobilized cellulose for berberine hydrochloride was a weak chemical adsorption, and the adsorption process was exothermic. The adsorption equilibrium was reached within 90 min in the initial concentration 100 mg/L, and the sorption kinetics fitted well to a pseudo-first-order model. Tannin-immobilized cellulose has potential application prospect in the field of the separation and purification of alkaloids.

Insights from the Structure of a Plant Cellulose Synthase Trimer.

Cellulose is an essential component of plant cell walls and the most abundant biopolymer on Earth. Despite its chemical simplicity, questions remain regarding the mechanisms of cellulose synthesis. A cryo-electron microscopy structure of a simplified plant cellulose synthase enzyme complex provides new insights into assembly, localization, and regulation of this complex.

In Vitro Synthesis and Self-Assembly of Cellulose II Nanofibrils Catalyzed by the Reverse Reaction of Clostridium thermocellum Cellodextrin Phosphorylase.

In nature, various organisms produce cellulose as microfibrils, which are processed into their nano- and microfibrillar and/or crystalline components by humans in order to obtain desired material properties. Interestingly, the natural synthesis machinery can be circumvented by enzymatically synthesizing cellulose from precursor molecules in vitro. This approach is appealing for producing tailor-made cellulosic particles and materials because it enables optimization of the reaction conditions for cellulose synthesis in order to generate particles with a desired morphology in their pure form. Here, we present enzymatic cellulose synthesis catalyzed by the reverse reaction of Clostridium thermocellum cellodextrin phosphorylase in vitro. We were able to produce cellulose II nanofibril networks in all conditions tested, using varying concentrations of the glycosyl acceptors d-glucose or d-cellobiose (0.5, 5, and 50 mM). We show that shorter cellulose chains assemble into flat ribbon-like fibrils with greater diameter, while longer chains assemble into cylindrical fibrils with smaller diameter.

The Effectivity of One-pot Concentrated Maleic Anhydride Hydrolysis for Betung Bamboo Pulp (Dendrocalamus asper sp)

Modification and synthesis of cellulose have attracted growing interest in the last decade due to applicable for many fields on advanced materials. Organic acid hydrolysis could be as an effective process for functionalization and size reduction of cellulose in one-pot reaction. The objective of this research is to study the effectivity of maleic acid anhydrous for functionalization and isolation of nanocellulose. Unbleached and Bleached Pulp of Betung Bamboo were used as cellulose resources. Concentrated maleic acid anhydride in 50% up to 60% (w/w) for 45 up to 90 minutes at 100 °C of reaction temperature were conducted to isolate cellulose nanocrsytals from betung bamboo pulp. Fibrillation treatment on fiber solid residue using ultrasonication result micrometers scale less than 1 μm for unbleached (UBB) and bleached (BB) fibrillated cellulose. Functionalization of carboxyl groups is more effective on UBB than BB with surface charge up to -48.5 mV and specific groups of carboxyl are detected in 1716 cm-1 and 1273 cm-1. Thermal stability also has similar tendency by Tonset in 313.69 °C and Tmax in 336.02 °C for UBB.