scholarly journals Hitting the Wall—Sensing and Signaling Pathways Involved in Plant Cell Wall Remodeling in Response to Abiotic Stress

Plants ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 89 ◽  
Author(s):  
Lazar Novaković ◽  
Tingting Guo ◽  
Antony Bacic ◽  
Arun Sampathkumar ◽  
Kim Johnson

Plant cells are surrounded by highly dynamic cell walls that play important roles regulating aspects of plant development. Recent advances in visualization and measurement of cell wall properties have enabled accumulation of new data about wall architecture and biomechanics. This has resulted in greater understanding of the dynamics of cell wall deposition and remodeling. The cell wall is the first line of defense against different adverse abiotic and biotic environmental influences. Different abiotic stress conditions such as salinity, drought, and frost trigger production of Reactive Oxygen Species (ROS) which act as important signaling molecules in stress activated cellular responses. Detection of ROS by still-elusive receptors triggers numerous signaling events that result in production of different protective compounds or even cell death, but most notably in stress-induced cell wall remodeling. This is mediated by different plant hormones, of which the most studied are jasmonic acid and brassinosteroids. In this review we highlight key factors involved in sensing, signal transduction, and response(s) to abiotic stress and how these mechanisms are related to cell wall-associated stress acclimatization. ROS, plant hormones, cell wall remodeling enzymes and different wall mechanosensors act coordinately during abiotic stress, resulting in abiotic stress wall acclimatization, enabling plants to survive adverse environmental conditions.

2019 ◽  
Vol 20 (7) ◽  
pp. 1758 ◽  
Author(s):  
Ingo Lenk ◽  
Lorraine Fisher ◽  
Martin Vickers ◽  
Aderemi Akinyemi ◽  
Thomas Didion ◽  
...  

Brachypodium distachyon is an established model for drought tolerance. We previously identified accessions exhibiting high tolerance, susceptibility and intermediate tolerance to drought; respectively, ABR8, KOZ1 and ABR4. Transcriptomics and metabolomic approaches were used to define tolerance mechanisms. Transcriptional analyses suggested relatively few drought responsive genes in ABR8 compared to KOZ1. Linking these to gene ontology (GO) terms indicated enrichment for “regulated stress response”, “plant cell wall” and “oxidative stress” associated genes. Further, tolerance correlated with pre-existing differences in cell wall-associated gene expression including glycoside hydrolases, pectin methylesterases, expansins and a pectin acetylesterase. Metabolomic assessments of the same samples also indicated few significant changes in ABR8 with drought. Instead, pre-existing differences in the cell wall-associated metabolites correlated with drought tolerance. Although other features, e.g., jasmonate signaling were suggested in our study, cell wall-focused events appeared to be predominant. Our data suggests two different modes through which the cell wall could confer drought tolerance: (i) An active response mode linked to stress induced changes in cell wall features, and (ii) an intrinsic mode where innate differences in cell wall composition and architecture are important. Both modes seem to contribute to ABR8 drought tolerance. Identification of the exact mechanisms through which the cell wall confers drought tolerance will be important in order to inform development of drought tolerant crops.


2020 ◽  
Vol 117 (6) ◽  
pp. 3281-3290 ◽  
Author(s):  
Lina Gallego-Giraldo ◽  
Chang Liu ◽  
Sara Pose-Albacete ◽  
Sivakumar Pattathil ◽  
Angelo Gabriel Peralta ◽  
...  

There is considerable interest in engineering plant cell wall components, particularly lignin, to improve forage quality and biomass properties for processing to fuels and bioproducts. However, modifying lignin content and/or composition in transgenic plants through down-regulation of lignin biosynthetic enzymes can induce expression of defense response genes in the absence of biotic or abiotic stress. Arabidopsis thaliana lines with altered lignin through down-regulation of hydroxycinnamoyl CoA:shikimate/quinate hydroxycinnamoyl transferase (HCT) or loss of function of cinnamoyl CoA reductase 1 (CCR1) express a suite of pathogenesis-related (PR) protein genes. The plants also exhibit extensive cell wall remodeling associated with induction of multiple cell wall-degrading enzymes, a process which renders the corresponding biomass a substrate for growth of the cellulolytic thermophile Caldicellulosiruptor bescii lacking a functional pectinase gene cluster. The cell wall remodeling also results in the release of size- and charge-heterogeneous pectic oligosaccharide elicitors of PR gene expression. Genetic analysis shows that both in planta PR gene expression and release of elicitors are the result of ectopic expression in xylem of the gene ARABIDOPSIS DEHISCENCE ZONE POLYGALACTURONASE 1 (ADPG1), which is normally expressed during anther and silique dehiscence. These data highlight the importance of pectin in cell wall integrity and the value of lignin modification as a tool to interrogate the informational content of plant cell walls.


Author(s):  
Arthur E. Sowers

All living organisms possess structures which are the result of macromolecular assembly processes. The mechanism and regulation of these processes is of fundamental importance and has a bearing on the structure and function problem. In the present research effort the phenomenon of silicification in the plant cell wall was the model assembly process. The silica rich cell wall of the Urtica pillulifera (common name: stinging nettle) stinging cell (shown in schematic form in Fig. 1) was the model system which displayed the phenomenon being studied. The silica is present in the form of electron- dense bodies with roughly spherical shapes. Based on morphology, the silica bodies fall into two classes: (1) primary silica bodies (Figs. 2,3) which have a narrow diameter distribution ( ave. = 50 nm ) and a compact and relatively lew electron density, and (2) secondary silica bodies (Fig. 4).


2020 ◽  
Vol 22 (22) ◽  
pp. 7924-7945
Author(s):  
Ninad Kothari ◽  
Samarthya Bhagia ◽  
Yunqiao Pu ◽  
Chang Geun Yoo ◽  
Mi Li ◽  
...  

Switchgrass, thermochemically pretreated switchgrass, and corresponding biologically digested residues were characterized to understand the process of lignocelluose deconstruction.


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