scholarly journals The Role of Brachypodium distachyon Wall-Associated Kinases (WAKs) in Cell Expansion and Stress Responses

Cells ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 2478
Author(s):  
Xingwen Wu ◽  
Antony Bacic ◽  
Kim L. Johnson ◽  
John Humphries
Keyword(s):  
Cell Wall ◽  
Stress Response ◽  
Plant Cell ◽  
Stress Responses ◽  
Cell Expansion ◽  
Plant Cell Wall ◽  
Brachypodium Distachyon ◽  
Critical Role ◽  
Cell Integrity

The plant cell wall plays a critical role in signaling responses to environmental and developmental cues, acting as both the sensing interface and regulator of plant cell integrity. Wall-associated kinases (WAKs) are plant receptor-like kinases located at the wall—plasma membrane—cytoplasmic interface and implicated in cell wall integrity sensing. WAKs in Arabidopsis thaliana have been shown to bind pectins in different forms under various conditions, such as oligogalacturonides (OG)s in stress response, and native pectin during cell expansion. The mechanism(s) WAKs use for sensing in grasses, which contain relatively low amounts of pectin, remains unclear. WAK genes from the model monocot plant, Brachypodium distachyon were identified. Expression profiling during early seedling development and in response to sodium salicylate and salt treatment was undertaken to identify WAKs involved in cell expansion and response to external stimuli. The BdWAK2 gene displayed increased expression during cell expansion and stress response, in addition to playing a potential role in the hypersensitive response. In vitro binding assays with various forms of commercial polysaccharides (pectins, xylans, and mixed-linkage glucans) and wall-extracted fractions (pectic/hemicellulosic/cellulosic) from both Arabidopsis and Brachypodium leaf tissues provided new insights into the binding properties of BdWAK2 and other candidate BdWAKs in grasses. The BdWAKs displayed a specificity for the acidic pectins with similar binding characteristics to the AtWAKs.

scholarly journals The plant cell wall integrity maintenance and immune signaling systems cooperate to control stress responses inArabidopsis thaliana

2018 ◽  
Vol 11 (536) ◽  
pp. eaao3070 ◽  
Author(s):  
Timo Engelsdorf ◽  
Nora Gigli-Bisceglia ◽  
Manikandan Veerabagu ◽  
Joseph F. McKenna ◽  
Lauri Vaahtera ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Stress Responses ◽  
Plant Cell Wall ◽  
Cell Wall Integrity ◽  
Immune Signaling ◽  
Signaling Systems

scholarly journals Fermentation and subsequent disposition of 14C-labelled plant cell wall material in the rat

1993 ◽  
Vol 69 (1) ◽  
pp. 189-197 ◽  
Author(s):  
D. F. Gray ◽  
M. A. Eastwood ◽  
W. G. Brydon ◽  
S. C. Fry
Keyword(s):  
Cell Wall ◽  
Gastrointestinal Tract ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Spinacia Oleracea ◽  
Wall Material ◽  
Fermentation Products ◽  
Bacterial Fermentation ◽  
Cell Wall Preparation

A 14C-Iabelled plant cell wall preparation (I4C-PCW) produced from spinach (Spinacia oleracea L.) cell culture exhibits uniform labelling of the major polysaccharide groups (%): pectins 53, hemicellulose 13, cellulose 21, starch 3. This 14C-PCW preparation has been used in rat studies as a marker for plant cell wall metabolism. Metabolism of the 14C-PCW occurred largely over the first 24 h. This was due to fermentation in the caecum. The pectic fraction of the plant cell walls was degraded completely in the rat gastrointestinal tract, but some [14C-]cellulose was still detected after 24 h in the colon. Of the 14C,22% was recovered in the host liver, adipose tissue and skin, 26% excreted as 14CO2 and up to 18%was excreted in the faeces. There was no urinary excretion of 14C. In vitro fermentation using a caecal inocuium showed reduced 14CO2 production, 12% compared with 26% in the intact rat. 14C-PCW is auseful marker to investigate the fate of plant cell wall materials in the gastrointestinal tract. These studies show both bacterial fermentation of the 14C-PCW and host metabolism of the 14C-labelled fermentation products.

scholarly journals Immunocytochemical Localization of HrpA and HrpZ Supports a Role for the Hrp Pilus in the Transfer of Effector Proteins from Pseudomonas syringae pv. tomato Across the Host Plant Cell Wall

2001 ◽  
Vol 14 (3) ◽  
pp. 394-404 ◽  
Author(s):  
Ian R. Brown ◽  
John W. Mansfield ◽  
Suvi Taira ◽  
Elina Roine ◽  
Martin Romantschuk
Keyword(s):  
Cell Wall ◽  
Pseudomonas Syringae ◽  
Plant Cell ◽  
Type Iii Secretion ◽  
Plant Cell Wall ◽  
Immunogold Labeling ◽  
Effector Proteins ◽  
Basal Bodies ◽  
Type Iii

The Hrp pilus, composed of HrpA subunits, is an essential component of the type III secretion system in Pseudomonas syringae. We used electron microscopy (EM) and immunocytochemistry to examine production of the pilus in vitro from P. syringae pv. tomato strain DC3000 grown under hrp-inducing conditions on EM grids. Pili, when labeled with antibodies to HrpA, developed rapidly in a nonpolar manner shortly after the detection of the hrpA transcript and extended up to 5 μm into surrounding media. Structures at the base of the pilus were clearly differentiated from the basal bodies of flagella. The HrpZ protein, also secreted via the type III system, was found by immunogold labeling to be associated with the pilus in vitro. Accumulation and secretion of HrpA and HrpZ were also examined quantitatively after the inoculation of wild-type DC3000 and hrpA and hrpZ mutants into leaves of Arabidopsis thaliana. The functional pilus crossed the plant cell wall to generate tracks of immunogold labeling for HrpA and HrpZ. Mutants that produced HrpA but did not assemble pili were nonpathogenic, did not secrete HrpA protein, and were compromised for the accumulation of HrpZ. A model is proposed in which the rapidly elongating Hrp pilus acts as a moving conveyor, facilitating transfer of effector proteins from bacteria to the plant cytoplasm across the formidable barrier of the plant cell wall.

scholarly journals A mixed-linkage (1,3;1,4)-β-D-glucan specific hydrolase mediates dark-triggered degradation of this plant cell wall polysaccharide

2021 ◽  
Author(s):  
Florian J Kraemer ◽  
China Lunde ◽  
Moritz Koch ◽  
Benjamin M Kuhn ◽  
Clemens Ruehl ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Large Scale ◽  
Plant Cell Wall ◽  
Causative Mutation ◽  
Grass Species ◽  
Calorie Intake ◽  
Cell Wall Polysaccharide ◽  
Transcript Accumulation

Abstract The presence of mixed-linkage (1,3;1,4)-β-D-glucan (MLG) in plant cell walls is a key feature of grass species such as cereals, the main source of calorie intake for humans and cattle. Accumulation of this polysaccharide involves the coordinated regulation of biosynthetic and metabolic machineries. While several components of the MLG biosynthesis machinery have been identified in diverse plant species, degradation of MLG is poorly understood. In this study, we performed a large-scale forward genetic screen for maize (Zea mays) mutants with altered cell wall polysaccharide structural properties. As a result, we identified a maize mutant with increased MLG content in several tissues, including adult leaves and senesced organs, where only trace amounts of MLG are usually detected. The causative mutation was found in the GRMZM2G137535 gene, encoding a GH17 licheninase as demonstrated by an in vitro activity assay of the heterologously expressed protein. In addition, maize plants overexpressing GRMZM2G137535 exhibit a 90% reduction in MLG content, indicating that the protein is not only required, but its expression is sufficient to degrade MLG. Accordingly, the mutant was named MLG hydrolase 1 (mlgh1). mlgh1 plants show increased saccharification yields upon enzymatic digestion. Stacking mlgh1 with lignin-deficient mutations results in synergistic increases in saccharification. Time profiling experiments indicate that wall MLG content is modulated during day/night cycles, inversely associated with MLGH1 transcript accumulation. This cycling is absent in the mlgh1 mutant, suggesting that the mechanism involved requires MLG degradation, which may in turn regulate MLGH1 gene expression.

scholarly journals Plant cell wall integrity maintenance and pattern-triggered immunity modulate jointly plant stress responses in Arabidopsis thaliana

2017 ◽  
Author(s):  
Timo Engelsdorf ◽  
Nora Gigli-Bisceglia ◽  
Manikandan Veerabagu ◽  
Joseph F. McKenna ◽  
Frauke Augstein ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Plant Growth ◽  
Plant Cell ◽  
Stress Responses ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Cell Wall Integrity ◽  
Maintenance Mechanism ◽  
Signaling Components

AbstractPlant cells are surrounded by walls, which must often meet opposing functional requirements during plant growth and defense. The cells meet them by modifying wall structure and composition in a tightly controlled and adaptive manner. The modifications seem to be mediated by a dedicated cell wall integrity (CWI) maintenance mechanism. Currently the mode of action of the mechanism is not understood and it is unclear how its activity is coordinated with established plant defense signaling. We investigated responses to induced cell wall damage (CWD) impairing CWI and the underlying mechanism in Arabidopsis thaliana. Interestingly inhibitor- and enzyme-derived CWD induced similar, turgor-sensitive stress responses. Genetic analysis showed that the receptor-like kinase (RLK) FEI2 and the mechano-sensitive, plasma membrane-localized Ca2+- channel MCA1 function downstream of the THE1 RLK in CWD perception. Phenotypic clustering with 27 genotypes identified a core group of RLKs and ion channels, required for activation of CWD responses. By contrast, the responses were repressed by pattern-triggered immune (PTI) signaling components including PEPR1 and 2, the receptors for the immune signaling peptide AtPep1. Interestingly AtPep1 application repressed CWD-induced phytohormone accumulation in a PEPR1/2-dependent manner. These results suggest that PTI suppresses CWD-induced defense responses through elicitor peptide-mediated signaling during defense response activation. If PTI is impaired, the suppression of CWD-induced responses is alleviated, thus compensating for defective PTI.Significance statementStress resistance and plant growth determine food crop yield and efficiency of bioenergy production from ligno-cellulosic biomass. Plant cell walls are essential elements of the biological processes, therefore functional integrity of the cell walls must be maintained throughout. Here we investigate the plant cell wall integrity maintenance mechanism. We characterize its mode of action, identify essential signaling components and show that the AtPep1 signaling peptide apparently coordinates pattern triggered immunity (PTI) and cell wall integrity maintenance in plants. These results suggest how PTI and cell wall modification coordinately regulate biotic stress responses with plants possibly compensating for PTI impairment through enhanced activation of stress responses regulated by the CWI maintenance mechanism.

scholarly journals Enzyme-assisted in vivo polymerisation of conjugated oligomer based conductors

2020 ◽  
Vol 8 (19) ◽  
pp. 4221-4227 ◽  
Author(s):  
Gwennaël Dufil ◽  
Daniela Parker ◽  
Jennifer Y. Gerasimov ◽  
Thuc-Quyen Nguyen ◽  
Magnus Berggren ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Plant Structure

The conjugated oligomer ETE-S is enzymatically polymerized in vitro, in the presence of peroxidase and H2O2. This polymerization route occurs also in the plant cell wall where ETE-S polymerizes and forms conductors along the plant structure.

scholarly journals A specific fungal transcription factor controls effector gene expression and orchestrates the establishment of the necrotrophic pathogen lifestyle on wheat

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Darcy A. B. Jones ◽  
Evan John ◽  
Kasia Rybak ◽  
Huyen T. T. Phan ◽  
Karam B. Singh ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Wall ◽  
Transcription Factor ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Cell Wall Degradation ◽  
Necrotrophic Pathogen ◽  
Effector Gene ◽  
Plant Cell Wall Degradation

Abstract The fungus Parastagonospora nodorum infects wheat through the use of necrotrophic effector (NE) proteins that cause host-specific tissue necrosis. The Zn2Cys6 transcription factor PnPf2 positively regulates NE gene expression and is required for virulence on wheat. Little is known about other downstream targets of PnPf2. We compared the transcriptomes of the P. nodorum wildtype and a strain deleted in PnPf2 (pf2-69) during in vitro growth and host infection to further elucidate targets of PnPf2 signalling. Gene ontology enrichment analysis of the differentially expressed (DE) genes revealed that genes associated with plant cell wall degradation and proteolysis were enriched in down-regulated DE gene sets in pf2-69 compared to SN15. In contrast, genes associated with redox control, nutrient and ion transport were up-regulated in the mutant. Further analysis of the DE gene set revealed that PnPf2 positively regulates twelve genes that encode effector-like proteins. Two of these genes encode proteins with homology to previously characterised effectors in other fungal phytopathogens. In addition to modulating effector gene expression, PnPf2 may play a broader role in the establishment of a necrotrophic lifestyle by orchestrating the expression of genes associated with plant cell wall degradation and nutrient assimilation.

scholarly journals Artificial scaffolds that mimic the plant extracellular environment for the culture and attachment of plant cells

2020 ◽  
Author(s):  
Ryan Calcutt ◽  
Richard Vincent ◽  
Derrick Dean ◽  
Treena Livingston Arinzeh ◽  
Ram Dixit
Keyword(s):  
Cell Fate ◽  
Plant Cell ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Piezoelectric Materials ◽  
Critical Role ◽  
Plant Cells ◽  
Cell Wall Polysaccharide ◽  
Native Plant

ABSTRACTPlant growth and development involves an intricate program of cell division and cell expansion to generate different cell types, tissue patterns and organ shapes. Plant cells are stuck together by their cell walls and the spatial context of cells within tissues plays a critical role in cell fate specification and morphogenesis. An in vitro model system to study plant development and its regulation by various extrinsic and intrinsic factors requires the ability to mimic the physical interactions between cells and their environment. Here, we present a set of artificial scaffolds to which cultured tobacco BY-2 cells adhere without causing morphological abnormalities. These scaffolds mimic native plant cell walls in terms of their fibrous nature, charge, hydrophobicity and piezoelectricity. We found that the extent of plant cell adhesion was essentially insensitive to the stiffness, fiber dimension, and fiber orientation of the scaffolds, but was affected by the piezoelectric properties of scaffolds where adhesion increased on piezoelectric materials. We also found that the plant cell wall polysaccharide, pectin, is largely responsible for adhesion to scaffolds, analogous to pectin-mediated adhesion of plant cells in tissues. Together, this work establishes biomimetic scaffolds that realistically emulate the plant tissue environment and provide the capability to develop microfluidic devices to study how cell-cell and cell-matrix interactions affect plant developmental pathways.

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