| 1. |
- Alonso-Simón, Ana, et al.
(författare)
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The use of FTIR spectroscopy to monitor modifications in plant cell wall architecture caused by cellulose biosynthesis inhibitors
- 2011
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Ingår i: Plant signaling & behavior. - : Informa UK Limited. - 1559-2324. ; 6:8, s. 1104-1110
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Tidskriftsartikel (refereegranskat)abstract
- Fourier Transform InfraRed (FTIR) spectroscopy is a powerful and rapid technique for analysing cell wall components and putative cross-links, which is able to non-destructively recognize polymers and functional groups and provide abundant information about their in muro organization. FTIR spectroscopy has been reported to be a useful tool for monitoring cell wall changes occurring in muro as a result of various factors, such as growth and development processes, mutations or biotic and abiotic stresses. This mini-review examines the use of FTIR spectroscopy in conjunction with multivariate analyses to monitor cell wall changes related to (1) the exposure of diverse plant materials to cellulose biosynthesis inhibitors (CBIs), and (2) the habituation/dehabituation of plant cell cultures to this kind of herbicides. The spectra analyses show differences not only regarding the inhibitor, but also regarding how long cells have been growing in its presence.
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| 2. |
- Bacete, Laura, et al.
(författare)
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Arabidopsis Response Regulator 6 (ARR6) Modulates Plant Cell-Wall Composition and Disease Resistance
- 2020
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Ingår i: Molecular Plant-Microbe Interactions. - : Scientific Societies. - 0894-0282 .- 1943-7706. ; 33:5, s. 767-780
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Tidskriftsartikel (refereegranskat)abstract
- The cytokinin signaling pathway, which is mediated by Arabidopsis response regulator (ARR) proteins, has been involved in the modulation of some disease-resistance responses. Here, we describe novel functions of ARR6 in the control of plant disease-resistance and cell-wall composition. Plants impaired in ARR6 function (arr6) were more resistant and susceptible, respectively, to the necrotrophic fungus Plectosphaerella cucumerina and to the vascular bacterium Ralstonia solanacearum, whereas Arabidopsis plants that overexpress ARR6 showed the opposite phenotypes, which further support a role of ARR6 in the modulation of disease-resistance responses against these pathogens. Transcriptomics and metabolomics analyses revealed that, in arr6 plants, canonical disease-resistance pathways, like those activated by defensive phytohormones, were not altered, whereas immune responses triggered by microbe-associated molecular patterns were slightly enhanced. Cell-wall composition of arr6 plants was found to be severely altered compared with that of wild-type plants. Remarkably, pectin-enriched cell-wall fractions extracted from arr6 walls triggered more intense immune responses than those activated by similar wall fractions from wild-type plants, suggesting that an-6 pectin fraction is enriched in wall-related damage-associated molecular patterns, which trigger immune responses. This work supports a novel function of ARR6 in the control of cell-wall composition and disease resistance and reinforces the role of the plant cell wall in the modulation of specific immune responses.
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| 3. |
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| 4. |
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| 5. |
- Belmonte, Rodrigo, et al.
(författare)
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Role of Pathogen-Derived Cell Wall Carbohydrates and Prostaglandin E-2 in Immune Response and Suppression of Fish Immunity by the Oomycete Saprolegnia parasitica
- 2014
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Ingår i: Infection and Immunity. - 0019-9567 .- 1098-5522. ; 82:11, s. 4518-4529
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Tidskriftsartikel (refereegranskat)abstract
- Saprolegnia parasitica is a freshwater oomycete that is capable of infecting several species of fin fish. Saprolegniosis, the disease caused by this microbe, has a substantial impact on Atlantic salmon aquaculture. No sustainable treatment against saprolegniosis is available, and little is known regarding the host response. In this study, we examined the immune response of Atlantic salmon to S. parasitica infection and to its cell wall carbohydrates. Saprolegnia triggers a strong inflammatory response in its host (i. e., induction of interleukin-1 beta(1) [IL-1 beta(1)], IL-6, and tumor necrosis factor alpha), while severely suppressing the expression of genes associated with adaptive immunity in fish, through downregulation of T-helper cell cytokines, antigen presentation machinery, and immunoglobulins. Oomycete cell wall carbohydrates were recognized by fish leukocytes, triggering upregulation of genes involved in the inflammatory response, similar to what is observed during infection. Our data suggest that S. parasitica is capable of producing prostaglanding E-2 (PGE(2)) in vitro, a metabolite not previously shown to be produced by oomycetes, and two proteins with homology to vertebrate enzymes known to play a role in prostaglandin biosynthesis have been identified in the oomycete genome. Exogenous PGE(2) was shown to increase the inflammatory response in fish leukocytes incubated with cell wall carbohydrates while suppressing genes involved in cellular immunity (gamma interferon [IFN-gamma] and the IFN-gamma-inducible protein [gamma-IP]). Inhibition of S. parasitica zoospore germination and mycelial growth by two cyclooxygenase inhibitors (aspirin and indomethacin) also suggests that prostaglandins may be involved in oomycete development.
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| 6. |
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| 7. |
- Escudero, Viviana, et al.
(författare)
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Alteration of cell wall xylan acetylation triggers defense responses that counterbalance the immune deficiencies of plants impaired in the beta-subunit of the heterotrimeric G-protein
- 2017
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Ingår i: The Plant Journal. - : WILEY. - 0960-7412 .- 1365-313X. ; 92:3, s. 386-399
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Tidskriftsartikel (refereegranskat)abstract
- Arabidopsis heterotrimeric G-protein complex modulates pathogen-associated molecular pattern-triggered immunity (PTI) and disease resistance responses to different types of pathogens. It also plays a role in plant cell wall integrity as mutants impaired in the G- (agb1-2) or G-subunits have an altered wall composition compared with wild-type plants. Here we performed a mutant screen to identify suppressors of agb1-2 (sgb) that restore susceptibility to pathogens to wild-type levels. Out of the four sgb mutants (sgb10-sgb13) identified, sgb11 is a new mutant allele of ESKIMO1 (ESK1), which encodes a plant-specific polysaccharide O-acetyltransferase involved in xylan acetylation. Null alleles (sgb11/esk1-7) of ESK1 restore to wild-type levels the enhanced susceptibility of agb1-2 to the necrotrophic fungus Plectosphaerella cucumerina BMM (PcBMM), but not to the bacterium Pseudomonas syringae pv. tomato DC3000 or to the oomycete Hyaloperonospora arabidopsidis. The enhanced resistance to PcBMM of the agb1-2 esk1-7 double mutant was not the result of the re-activation of deficient PTI responses in agb1-2. Alteration of cell wall xylan acetylation caused by ESK1 impairment was accompanied by an enhanced accumulation of abscisic acid, the constitutive expression of genes encoding antibiotic peptides and enzymes involved in the biosynthesis of tryptophan-derived metabolites, and the accumulation of disease resistance-related secondary metabolites and different osmolites. These esk1-mediated responses counterbalance the defective PTI and PcBMM susceptibility of agb1-2 plants, and explain the enhanced drought resistance of esk1 plants. These results suggest that a deficient PTI-mediated resistance is partially compensated by the activation of specific cell-wall-triggered immune responses. Significance Statement The plant heterotrimeric G protein complex is an essential component of Pathogen Associated Molecular Pattern-triggered immunity (PTI) and of plant disease resistance to several types of pathogens. We found that modification of the degree of xylan acetylation in plant cell walls activates PTI-independent resistance responses that counterbalance the hypersusceptibility to particular pathogens of plants lacking the heterotrimeric G subunit. These data demonstrate that immune deficient response can be partially compensated by the activation of cell wall-triggered immunity that confers specific disease resistance.
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| 8. |
- García-Angulo, Penélope, et al.
(författare)
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Habituation and dehabituation to dichlobenil : simply the equivalent of Penélope's weaving and unweaving process?
- 2009
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Ingår i: Plant signaling & behavior. - : Informa UK Limited. - 1559-2324. ; 4:11, s. 1069-1071
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Tidskriftsartikel (refereegranskat)abstract
- The habituation of cell cultures to cellulose biosynthesis inhibitors constitutes a valuable method for learning more about the plasticity of plant cell wall composition and structure. The subculture of habituated cells in the absence of an inhibitor (dehabituation) offers complementary information: some habituation-associated modifications revert, whereas others remain, even after long-term (3-5 years) dehabituation processes. However, is dehabituation simply the opposite to the process of habituation, in the same way that the cloth woven by Penélope during the day was unwoven during the night? Principal Component Analysis applied to Fourier Transformed Infrared (FTIR) spectra of cell walls from dichlobenil-habituated and dehabituated bean cell lines has shown that dehabituation follows a different pathway to that of habituation. Principal component loadings show that dehabituated cells have more pectins, but that these display a lower degree of methyl-esterification, than those of habituated ones. Further analysis of cell walls focusing on the first steps of habituation would serve to identify which specific modifications in pectins are responsible to the fine modulation of cell wall architecture observed during the habituation/dehabituation process.
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| 9. |
- García-Angulo, Penélope, et al.
(författare)
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High peroxidase activity and stable changes in the cell wall are related to dichlobenil tolerance
- 2009
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Ingår i: Journal of plant physiology (Print). - : Elsevier BV. - 0176-1617 .- 1618-1328. ; 166:12, s. 1229-1240
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Tidskriftsartikel (refereegranskat)abstract
- Suspension-cultured bean cells habituated to growth in a lethal concentration of dichlobenil were cultured for 3-5 years in a medium lacking the inhibitor in order to obtain long-term dehabituated cell lines. The growth parameters, cell morphology and ultrastructure of cells in the absence of dichlobenil reverted to that of non-habituated cells. The cellulose content and Fourier transform infrared (FTIR) spectra of crude cell walls from long-term dehabituated cells were also similar to those of non-habituated cells. However, long-term dehabituated cells showed three times more tolerance to dichlobenil than non-habituated cells. The incorporation of [(14)C]Glc into cellulose was reduced by 40% in dehabituated cells when compared with non-habituated cells. However, the addition of dichlobenil to dehabituated cells increased the incorporation of [(14)C]Glc into cellulose 3.3-fold with respect to that of non-habituated cells. Dehabituated cells showed a constitutively increased peroxidase activity when compared with non-habituated cells. Results reported here indicate that the habituation of bean cultured cells to dichlobenil relied partially on a stable change in the cellulose biosynthesis complex and is associated with high guaiacol peroxidase activity.
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| 10. |
- Kopplin, G., et al.
(författare)
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Structural Characterization of Fucoidan from Laminaria hyperborea : Assessment of Coagulation and Inflammatory Properties and Their Structure-Function Relationship
- 2018
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Ingår i: ACS Applied Bio Materials. - : American Chemical Society (ACS). - 2576-6422. ; 1:6, s. 1880-1892
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Tidskriftsartikel (refereegranskat)abstract
- The structure of fucoidan isolated from Laminaria hyperborea was elucidatedand chemically tailored in order to obtain a clear structure−function relationship on bioactiveproperties with a minimal amount of variations among the tested molecules. Analysis revealeda sugar composition of 97.8% fucose and 2.2% galactose. Analysis of the glycosidic linkagesshowed (1→3)-α-L-fuco-pyranose (31.9%) to be the dominant residue, followed by 1→2-linked (13.2%) and 1→4-linked (7.7%) fuco-pyranose as well as a high degree of branching(22.4%). Inductively coupled plasma mass spectrometry (ICP-MS) revealed a sulfate contentof 53.8% (degree of sulfation (DS) = 1.7). Raman spectroscopy determined SO4 located axialat 4C and equatorial at 2C as well as an absence of acetylation. SEC-MALS analysisdetermined a high molecular weight (Mw = 469 kDa), suggesting a highly flexible main chainwith short side chains. Both chemical shifts of the fucoidan, proton, and carbon were assignedby NMR and revealed a highly heterogeneous structure in terms of glycosidic linkages.Bioactivity was assessed using a lepirudin-based whole blood model. The immediate responsesby coagulation and complement cascades were measured by prothrombine factor 1 and 2(PTF1.2) and the terminal complement complex (TCC). Cytokines involved in inflammation were detected in a 27-plexcytokine assay. Fucoidan with a high Mw and DS inhibited coagulation, complement, and the cytokines PDGF-BB, RANTES,and IP-10, while activating MCP-1. These effects were obtained at the concentration of 1000 ug/mL and partly at 100 ug/mL.In low concentrations (10 ug/mL), a coagulation stimulating effect of highly sulfated fucoidans (DS = 1.7, Mw = 469 kDa or20.3) was obtained. These data point to a multitude of effects linked to the sulfation degree that needs further mechanisticexploration.
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