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Christian A Voigt - One of the best experts on this subject based on the ideXlab platform.
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3 aminobenzamide blocks mamp induced Callose deposition independently of its poly adpribosyl ation inhibiting activity
Frontiers in Plant Science, 2018Co-Authors: Brian D Keppler, Christian A Voigt, Junqi Song, Jackson Nyman, Andrew F BentAbstract:Cell wall reinforcement with Callose is a frequent plant response to infection. Poly(ADP-ribosyl)ation is a protein post-translational modification mediated by poly(ADP-ribose) polymerases (PARPs). Poly(ADP-ribosyl)ation has well-known roles in DNA damage repair and has more recently been shown to contribute to plant immune responses. 3-aminobenzamide (3AB) is an established PARP inhibitor and it blocks the Callose deposition elicited by flg22 or elf18, two microbe-associated molecular patterns (MAMPs). However, we report that an Arabidopsis parp1parp2parp3 triple mutant does not exhibit loss of flg22-induced Callose deposition. Additionally, the more specific PARP inhibitors PJ-34 and INH2BP inhibit PARP activity in Arabidopsis but do not block MAMP-induced Callose deposition. These data demonstrate off-target activity of 3AB and indicate that 3AB inhibits Callose deposition through a mechanism other than poly(ADP-ribosyl)ation. POWDERY MILDEW RESISTANT 4 (PMR4) is the Callose synthase responsible for the majority of MAMP- and wound-induced Callose deposition in Arabidopsis. 3AB does not block wound-induced Callose deposition, and 3AB does not reduce the PMR4 mRNA abundance increase in response to flg22. Levels of PMR4-HA protein increase in response to flg22, and increase even more in flg22 + 3AB despite no Callose being produced. The Callose synthase inhibitor 2-deoxy-D-glucose does not cause similar impacts on PMR4-HA protein levels. Beyond MAMPs, we find that 3AB also reduces Callose deposition induced by powdery mildew (Golovinomyces cichoracearum) and impairs the penetration resistance of a PMR4 overexpression line. 3AB thus reveals pathogenesis-associated pathways that activate Callose synthase enzymatic activity distinct from those that elevate PMR4 mRNA and protein abundance.
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Data_Sheet_1_3-Aminobenzamide Blocks MAMP-Induced Callose Deposition Independently of Its Poly(ADPribosyl)ation Inhibiting Activity.PDF
2018Co-Authors: Brian D Keppler, Christian A Voigt, Junqi Song, Jackson Nyman, Andrew F BentAbstract:Cell wall reinforcement with Callose is a frequent plant response to infection. Poly(ADP-ribosyl)ation is a protein post-translational modification mediated by poly(ADP-ribose) polymerases (PARPs). Poly(ADP-ribosyl)ation has well-known roles in DNA damage repair and has more recently been shown to contribute to plant immune responses. 3-aminobenzamide (3AB) is an established PARP inhibitor and it blocks the Callose deposition elicited by flg22 or elf18, two microbe-associated molecular patterns (MAMPs). However, we report that an Arabidopsis parp1parp2parp3 triple mutant does not exhibit loss of flg22-induced Callose deposition. Additionally, the more specific PARP inhibitors PJ-34 and INH2BP inhibit PARP activity in Arabidopsis but do not block MAMP-induced Callose deposition. These data demonstrate off-target activity of 3AB and indicate that 3AB inhibits Callose deposition through a mechanism other than poly(ADP-ribosyl)ation. POWDERY MILDEW RESISTANT 4 (PMR4) is the Callose synthase responsible for the majority of MAMP- and wound-induced Callose deposition in Arabidopsis. 3AB does not block wound-induced Callose deposition, and 3AB does not reduce the PMR4 mRNA abundance increase in response to flg22. Levels of PMR4-HA protein increase in response to flg22, and increase even more in flg22 + 3AB despite no Callose being produced. The Callose synthase inhibitor 2-deoxy-D-glucose does not cause similar impacts on PMR4-HA protein levels. Beyond MAMPs, we find that 3AB also reduces Callose deposition induced by powdery mildew (Golovinomyces cichoracearum) and impairs the penetration resistance of a PMR4 overexpression line. 3AB thus reveals pathogenesis-associated pathways that activate Callose synthase enzymatic activity distinct from those that elevate PMR4 mRNA and protein abundance.
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cellulose and Callose synthesis and organization in focus what s new
Current Opinion in Plant Biology, 2016Co-Authors: Rene Schneider, Tobias Hanak, Staffan Persson, Christian A VoigtAbstract:Plant growth and development are supported by plastic but strong cell walls. These walls consist largely of polysaccharides that vary in content and structure. Most of the polysaccharides are produced in the Golgi apparatus and are then secreted to the apoplast and built into the growing walls. However, the two glucan polymers cellulose and Callose are synthesized at the plasma membrane by cellulose or Callose synthase complexes, respectively. Cellulose is the most common cell wall polymer in land plants and provides strength to the walls to support directed cell expansion. In contrast, Callose is integral to specialized cell walls, such as the cell plate that separates dividing cells and growing pollen tube walls, and maintains important functions during abiotic and biotic stress responses. The last years have seen a dramatic increase in our understanding of how cellulose and Callose are manufactured, and new factors that regulate the synthases have been identified. Much of this knowledge has been amassed via various microscopy-based techniques, including various confocal techniques and super-resolution imaging. Here, we summarize and synthesize recent findings in the fields of cellulose and Callose synthesis in plant biology.
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Callose biosynthesis in arabidopsis with a focus on pathogen response what we have learned within the last decade
Annals of Botany, 2014Co-Authors: Dorothea Ellinger, Christian A VoigtAbstract:Background (1,3)-β-Glucan Callose is a cell wall polymer that is involved in several fundamental biological processes, ranging from plant development to the response to abiotic and biotic stresses. Despite its importance in maintaining plant integrity and plant defence, knowledge about the regulation of Callose biosynthesis at its diverse sites of action within the plant is still limited. The moderately sized family of GSL (GLUCAN SYNTHASE-LIKE) genes is predicted to encode Callose synthases with a specific biological function and subcellular localization. Phosphorylation and directed translocation of Callose synthases seem to be key post-translational mechanisms of enzymatic regulation, whereas transcriptional control of GSL genes might only have a minor function in response to biotic or abiotic stresses. Scope and conclusions Among the different sites of Callose biosynthesis within the plant, particular attention has been focused on the formation of Callose in response to pathogen attack. Here, Callose is deposited between the plasma membrane and the cell wall to act as a physical barrier to stop or slow invading pathogens. Arabidopsis (Arabidopsis thaliana) is one of the best-studied models not only for general plant defence responses but also for the regulation of pathogen-induced Callose biosynthesis. Callose synthase GSL5 (GLUCAN SYNTHASE-LIKE5) has been shown to be responsible for stress-induced Callose deposition. Within the last decade of research into stress-induced Callose, growing evidence has been found that the timing of Callose deposition in the multilayered system of plant defence responses could be the key parameter for optimal effectiveness. This timing seems to be achieved through co-ordinated transport and formation of the Callose synthase complex.
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interaction of the arabidopsis gtpase raba4c with its effector pmr4 results in complete penetration resistance to powdery mildew
The Plant Cell, 2014Co-Authors: Dorothea Ellinger, Annemarie Glockner, Jasmin Koch, Vanessa Sturtz, Kevin Schutt, Shauna C Somerville, Christian A Voigt, Chithra Manisseri, Marcel NaumannAbstract:The (1,3)-β-glucan Callose is a major component of cell wall thickenings in response to pathogen attack in plants. GTPases have been suggested to regulate pathogen-induced Callose biosynthesis. To elucidate the regulation of Callose biosynthesis in Arabidopsis thaliana, we screened microarray data and identified transcriptional upregulation of the GTPase RabA4c after biotic stress. We studied the function of RabA4c in its native and dominant negative (dn) isoform in RabA4c overexpression lines. RabA4c overexpression caused complete penetration resistance to the virulent powdery mildew Golovinomyces cichoracearum due to enhanced Callose deposition at early time points of infection, which prevented fungal ingress into epidermal cells. By contrast, RabA4c(dn) overexpression did not increase Callose deposition or penetration resistance. A cross of the resistant line with the pmr4 disruption mutant lacking the stress-induced Callose synthase PMR4 revealed that enhanced Callose deposition and penetration resistance were PMR4-dependent. In live-cell imaging, tagged RabA4c was shown to localize at the plasma membrane prior to infection, which was broken in the pmr4 disruption mutant background, with Callose deposits at the site of attempted fungal penetration. Together with our interactions studies including yeast two-hybrid, pull-down, and in planta fluorescence resonance energy transfer assays, we concluded that RabA4c directly interacts with PMR4, which can be seen as an effector of this GTPase.
Zonglie Hong - One of the best experts on this subject based on the ideXlab platform.
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expression of arabidopsis Callose synthase 5 results in Callose accumulation and cell wall permeability alteration
Plant Science, 2012Co-Authors: Bo Xie, Yunfei Deng, Masahiro M Kanaoka, Kiyotaka Okada, Zonglie HongAbstract:Callose is the major polysaccharide present in the Callose wall of developing microspores and the growing pollen tube wall. It is also an essential component of other specialized cell walls and its synthesis can be induced by pathogen infection, wounding and environmental cues. Among the 12 Callose synthase genes (CalS) present in the Arabidopsis genome, CalS5 plays the predominant role in the synthesis of the Callose wall, Callose plugs and pollen tube wall. When expressed as a GFP-tagged protein in cultured tobacco BY-2 cells, CalS5 was found to be present in the plasma membrane and the Golgi-related endomembranes. Unlike the cell plate-specific CalS1 isozyme, CalS5 was not concentrated to the cell plate at cytokinesis. Expression of CalS5 resulted in Callose accumulation only in the cell wall of BY-2 cells. The fact that no Callose was found in the endomembranes suggests that CalS5 is not functional in that compartment. These cells exhibited a decreased plasmolysis rate in hypotonic solutions and an increased cytolysis rate in hypertonic conditions. This study demonstrates that an artificial Callose wall could be synthesized by expressing a Callose synthase enzyme.
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cals7 encodes a Callose synthase responsible for Callose deposition in the phloem
Plant Journal, 2011Co-Authors: Bo Xie, Zhongming Zhang, Xiaomin Wang, Maosheng Zhu, Zonglie HongAbstract:It has been known for more than a century that sieve plates in the phloem in plants contain Callose, a β-1,3-glucan. However, the genes responsible for Callose deposition in this subcellular location have not been identified. In this paper we examine Callose deposition patterns in T-DNA insertion mutants (cs7) of the Callose Synthase 7 (CalS7) gene. We demonstrated here that the CalS7 gene is expressed specifically in the phloem of vascular tissues. Callose deposition in the phloem, especially in the sieve elements, was greatly reduced in cs7 mutants. Ultrastructural analysis of developing sieve elements revealed that Callose failed to accumulate in the plasmodesmata of incipient sieve plates at the early perforation stage of phloem development, resulting in the formation of sieve plates with fewer pores. In wild-type Arabidopsis plants, Callose is present as a constituent polysaccharide in the phloem of the stem, and its accumulation can also be induced by wounding. Callose accumulation in both conditions was eliminated in mature sieve plates of cs7 mutants. These results demonstrate that CalS7 is a phloem-specific Callose synthase gene, and is responsible for Callose deposition in developing sieve elements during phloem formation and in mature phloem induced by wounding. The mutant plants exhibited moderate reduction in seedling height and produced aberrant pollen grains and short siliques with aborted embryos, suggesting that CalS7 also plays a role in plant growth and reproduction.
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Callose synthase cals5 is required for exine formation during microgametogenesis and for pollen viability in arabidopsis
Plant Journal, 2005Co-Authors: Xiaoyun Dong, Zonglie Hong, Muthuswamy Sivaramakrishnan, Magdy M Mahfouz, Desh Pal S VermaAbstract:Summary Callose (β-1,3-glucan) is produced at different locations in response to biotic and abiotic cues. Arabidopsis contains 12 genes encoding Callose synthase (CalS). We demonstrate that one of these genes, CalS5, encodes a Callose synthase which is responsible for the synthesis of Callose deposited at the primary cell wall of meiocytes, tetrads and microspores, and the expression of this gene is essential for exine formation in pollen wall. CalS5 encodes a transmembrane protein of 1923 amino acid residues with a molecular mass of 220 kDa. Knockout mutations of the CalS5 gene by T-DNA insertion resulted in a severe reduction in fertility. The reduced fertility in the cals5 mutants is attributed to the degeneration of microspores. However, megagametogenesis is not affected and the female gametes are completely fertile in cals5 mutants. The CalS5 gene is also expressed in other organs with the highest expression in meiocytes, tetrads, microspores and mature pollen. Callose deposition in the cals5 mutant was nearly completely lacking, suggesting that this gene is essential for the synthesis of Callose in these tissues. As a result, the pollen exine wall was not formed properly, affecting the baculae and tectum structure and tryphine was deposited randomly as globular structures. These data suggest that Callose synthesis has a vital function in building a properly sculpted exine, the integrity of which is essential for pollen viability.
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Plant Callose synthase complexes
Plant Molecular Biology, 2001Co-Authors: Desh Pal S Verma, Zonglie HongAbstract:Synthesis of Callose (β-1,3-glucan) in plants has been a topic of much debate over the past several decades. Callose synthase could not be purified to homogeneity and most partially purified cellulose synthase preparations yielded β-1,3-glucan in vitro , leading to the interpretation that cellulose synthase might be able to synthesize Callose. While a rapid progress has been made on the genes involved in cellulose synthesis in the past five years, identification of genes for Callose synthases has proven difficult because cognate genes had not been identified in other organisms. An Arabidopsis gene encoding a putative cell plate-specific Callose synthase catalytic subunit (CalS1) was recently cloned. CalS1 shares high sequence homology with the well-characterized yeast β-1,3-glucan synthase and transgenic plant cells over-expressing CalS1 display higher Callose synthase activity and accumulate more Callose. The Callose synthase complex exists in at least two distinct forms in different tissues and interacts with phragmoplastin, UDP-glucose transferase, Rop1 and, possibly, annexin. There are 12 CalS isozymes in Arabidopsis , and each may be tissue-specific and/or regulated under different physiological conditions responding to biotic and abiotic stresses.
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A Novel UDP-Glucose Transferase Is Part of the Callose Synthase Complex and Interacts with Phragmoplastin at the Forming Cell Plate
The Plant Cell, 2001Co-Authors: Zonglie Hong, John M Olson, Zhongming Zhang, Desh Pal S VermaAbstract:Using phragmoplastin as a bait, we isolated an Arabidopsis cDNA encoding a novel UDP-glucose transferase (UGT1). This interaction was confirmed by an in vitro protein–protein interaction assay using purified UGT1 and radiolabeled phragmoplastin. Protein gel blot results revealed that UGT1 is associated with the membrane fraction and copurified with the product-entrapped Callose synthase complex. These data suggest that UGT1 may act as a subunit of Callose synthase that uses UDP-glucose to synthesize Callose, a 1,3-β-glucan. UGT1 also interacted with Rop1, a Rho-like protein, and this interaction occurred only in its GTP-bound configuration, suggesting that the plant Callose synthase may be regulated by Rop1 through the interaction with UGT1. The green fluorescent protein–UGT1 fusion protein was located on the forming cell plate during cytokinesis. We propose that UGT1 may transfer UDP-glucose from sucrose synthase to the Callose synthase and thus help form a substrate channel for the synthesis of Callose at the forming cell plate.
Georgia Drakakaki - One of the best experts on this subject based on the ideXlab platform.
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Callose deposition is essential for the completion of cytokinesis in the unicellular alga penium margaritaceum
bioRxiv, 2020Co-Authors: Destiny J. Davis, Minmin Wang, Iben Sorensen, Jocelyn K C Rose, David S Domozych, Georgia DrakakakiAbstract:Abstract Cytokinesis in land plants involves the formation of a cell plate that develops into the new cell wall. Callose is a β-1,3 glucan that transiently accumulates at later stages of cell plate development and is thought to stabilize the delicate membrane network of the cell plate as it expands. Cytokinetic Callose deposition is currently considered specific to multicellular plant species as it has not been detected in unicellular algae. Here we present Callose at the cytokinesis junction of the unicellular charophyte, Penium margaritaceum. Notably, Callose deposition at the division plane of P. margaritaceum showed distinct, spatiotemporal patterns that could represent distinct roles of this polymer in cytokinesis and cell wall assembly. Pharmacological inhibition of cytokinetic Callose deposition by Endosidin 7 treatment resulted in cytokinesis defects, consistent with the essential role for this polymer in P. margaritaceum cell division. Cell wall deposition and assembly at the isthmus zone was also affected by the absence of Callose, demonstrating the dynamic nature of new wall assembly in P. margaritaceum. The identification of candidate Callose synthase genes provides molecular evidence for Callose biosynthesis in P. margaritaceum. The evolutionary implications of cytokinetic Callose in this unicellular Zygnematopycean alga is discussed in the context of the conquest of land by plants. Summary Statement Evolutionarily conserved Callose in Penium margaritaceum is essential for the completion of cytokinesis.
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Callose deposition is essential for the completion of cytokinesis in the unicellular alga penium margaritaceum
Journal of Cell Science, 2020Co-Authors: Destiny J. Davis, Minmin Wang, Iben Sorensen, Jocelyn K C Rose, David S Domozych, Georgia DrakakakiAbstract:Cytokinesis in land plants involves the formation of a cell plate that develops into the new cell wall. Callose, a β-1,3 glucan accumulates at later stages of cell plate development presumably to stabilize this delicate membrane network during expansion. Cytokinetic Callose is considered specific to multicellular plant species, as it has not been detected in unicellular algae. Here we present Callose at the cytokinesis junction of the unicellular charophyte, P. margaritaceum. Callose deposition at the division plane of P. margaritaceum showed distinct, spatiotemporal patterns likely representing distinct roles of this polymer in cytokinesis. Pharmacological inhibition by Endosidin 7 resulted in cytokinesis defects, consistent with the essential role for this polymer in P. margaritaceum cell division. Cell wall deposition at the isthmus zone was also affected by the absence of Callose, demonstrating the dynamic nature of new wall assembly in P. margaritaceum. The identification of candidate Callose synthase genes provides molecular evidence for Callose biosynthesis in P. margaritaceum. The evolutionary implications of cytokinetic Callose in this unicellular Zygnematopycean alga is discussed in the context of the conquest of land by plants.
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Endosidin 7 Specifically Arrests Late Cytokinesis and Inhibits Callose Biosynthesis, Revealing Distinct Trafficking Events during Cell Plate Maturation
Plant Physiology, 2014Co-Authors: Eunsook Park, Thomas Wilkop, Sara M. Díaz-moreno, Destiny J. Davis, Vincent Bulone, Georgia DrakakakiAbstract:Although cytokinesis is vital for plant growth and development, our mechanistic understanding of the highly regulated membrane and cargo transport mechanisms in relation to polysaccharide deposition during this process is limited. Here, we present an in-depth characterization of the small molecule endosidin 7 (ES7) inhibiting Callose synthase activity and arresting late cytokinesis both in vitro and in vivo in Arabidopsis (Arabidopsis thaliana). ES7 is a specific inhibitor for plant Callose deposition during cytokinesis that does not affect endomembrane trafficking during interphase or cytoskeletal organization. The specificity of ES7 was demonstrated (1) by comparing its action with that of known inhibitors such as caffeine, flufenacet, and concanamycin A and (2) across kingdoms with a comparison in yeast. The interplay between cell plate-specific post-Golgi vesicle traffic and Callose accumulation was analyzed using ES7, and it revealed unique and temporal contributions of secretory and endosomal vesicles in cell plate maturation. While RABA2A-labeled vesicles, which accumulate at the early stage of cell plate formation, were not affected by ES7, KNOLLE was differentially altered by the small molecule. In addition, the presence of clathrin-coated vesicles in cells containing elevated levels of Callose and their reduction under ES7 treatment further support the role of endocytic membrane remodeling in the maturing cell plate while the plate is stabilized by Callose. Taken together, these data show the essential role of Callose during the late stages of cell plate maturation and establish the temporal relationship between vesicles and regulatory proteins at the cell plate assembly matrix during polysaccharide deposition.
Dorothea Ellinger - One of the best experts on this subject based on the ideXlab platform.
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Callose biosynthesis in arabidopsis with a focus on pathogen response what we have learned within the last decade
Annals of Botany, 2014Co-Authors: Dorothea Ellinger, Christian A VoigtAbstract:Background (1,3)-β-Glucan Callose is a cell wall polymer that is involved in several fundamental biological processes, ranging from plant development to the response to abiotic and biotic stresses. Despite its importance in maintaining plant integrity and plant defence, knowledge about the regulation of Callose biosynthesis at its diverse sites of action within the plant is still limited. The moderately sized family of GSL (GLUCAN SYNTHASE-LIKE) genes is predicted to encode Callose synthases with a specific biological function and subcellular localization. Phosphorylation and directed translocation of Callose synthases seem to be key post-translational mechanisms of enzymatic regulation, whereas transcriptional control of GSL genes might only have a minor function in response to biotic or abiotic stresses. Scope and conclusions Among the different sites of Callose biosynthesis within the plant, particular attention has been focused on the formation of Callose in response to pathogen attack. Here, Callose is deposited between the plasma membrane and the cell wall to act as a physical barrier to stop or slow invading pathogens. Arabidopsis (Arabidopsis thaliana) is one of the best-studied models not only for general plant defence responses but also for the regulation of pathogen-induced Callose biosynthesis. Callose synthase GSL5 (GLUCAN SYNTHASE-LIKE5) has been shown to be responsible for stress-induced Callose deposition. Within the last decade of research into stress-induced Callose, growing evidence has been found that the timing of Callose deposition in the multilayered system of plant defence responses could be the key parameter for optimal effectiveness. This timing seems to be achieved through co-ordinated transport and formation of the Callose synthase complex.
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interaction of the arabidopsis gtpase raba4c with its effector pmr4 results in complete penetration resistance to powdery mildew
The Plant Cell, 2014Co-Authors: Dorothea Ellinger, Annemarie Glockner, Jasmin Koch, Vanessa Sturtz, Kevin Schutt, Shauna C Somerville, Christian A Voigt, Chithra Manisseri, Marcel NaumannAbstract:The (1,3)-β-glucan Callose is a major component of cell wall thickenings in response to pathogen attack in plants. GTPases have been suggested to regulate pathogen-induced Callose biosynthesis. To elucidate the regulation of Callose biosynthesis in Arabidopsis thaliana, we screened microarray data and identified transcriptional upregulation of the GTPase RabA4c after biotic stress. We studied the function of RabA4c in its native and dominant negative (dn) isoform in RabA4c overexpression lines. RabA4c overexpression caused complete penetration resistance to the virulent powdery mildew Golovinomyces cichoracearum due to enhanced Callose deposition at early time points of infection, which prevented fungal ingress into epidermal cells. By contrast, RabA4c(dn) overexpression did not increase Callose deposition or penetration resistance. A cross of the resistant line with the pmr4 disruption mutant lacking the stress-induced Callose synthase PMR4 revealed that enhanced Callose deposition and penetration resistance were PMR4-dependent. In live-cell imaging, tagged RabA4c was shown to localize at the plasma membrane prior to infection, which was broken in the pmr4 disruption mutant background, with Callose deposits at the site of attempted fungal penetration. Together with our interactions studies including yeast two-hybrid, pull-down, and in planta fluorescence resonance energy transfer assays, we concluded that RabA4c directly interacts with PMR4, which can be seen as an effector of this GTPase.
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elevated early Callose deposition results in complete penetration resistance to powdery mildew in arabidopsis
Plant Physiology, 2013Co-Authors: Dorothea Ellinger, Shauna C Somerville, Claudia Zwikowics, Torsten Jamrow, Christian Falter, Chithra Manisseri, Marcel Naumann, Christian A VoigtAbstract:A common response by plants to fungal attack is deposition of Callose, a (1,3)-β-glucan polymer, in the form of cell wall thickenings called papillae, at site of wall penetration. While it has been generally believed that the papillae provide a structural barrier to slow fungal penetration, this idea has been challenged in recent studies of Arabidopsis (Arabidopsis thaliana), where fungal resistance was found to be independent of Callose deposition. To the contrary, we show that Callose can strongly support penetration resistance when deposited in elevated amounts at early time points of infection. We generated transgenic Arabidopsis lines that express POWDERY MILDEW RESISTANT4 (PMR4), which encodes a stress-induced Callose synthase, under the control of the constitutive 35S promoter. In these lines, we detected Callose synthase activity that was four times higher than that in wild-type plants 6 h post inoculation with the virulent powdery mildew Golovinomyces cichoracearum. The Callose synthase activity was correlated with enlarged Callose deposits and the focal accumulation of green fluorescent protein-tagged PMR4 at sites of attempted fungal penetration. We observed similar results from infection studies with the nonadapted powdery mildew Blumeria graminis f. sp. hordei. Haustoria formation was prevented in resistant transgenic lines during both types of powdery mildew infection, and neither the salicylic acid-dependent nor jasmonate-dependent pathways were induced. We present a schematic model that highlights the differences in Callose deposition between the resistant transgenic lines and the susceptible wild-type plants during compatible and incompatible interactions between Arabidopsis and powdery mildew.
Jae-yean Kim - One of the best experts on this subject based on the ideXlab platform.
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Callose balancing at plasmodesmata.
Journal of experimental botany, 2018Co-Authors: Wu Shuwei, Arya Bagus Boedi Iswanto, Ritesh Kumar, Jae-yean KimAbstract:In plants, communication and molecular exchanges between different cells and tissues are dependent on the apoplastic and symplastic pathways. Symplastic molecular exchanges take place through the plasmodesmata, which connect the cytoplasm of neighboring cells in a highly controlled manner. Callose, a β-1,3-glucan polysaccharide, is a plasmodesmal marker molecule that is deposited in cell walls near the neck zone of plasmodesmata and controls their permeability. During cell differentiation and plant development, and in response to diverse stresses, the level of Callose in plasmodesmata is highly regulated by two antagonistic enzymes, Callose synthase or glucan synthase-like and β-1,3-glucanase. The diverse modes of regulation by Callose synthase and β-1,3-glucanase have been uncovered in the past decades through biochemical, molecular, genetic, and omics methods. This review highlights recent findings regarding the function of plasmodesmal Callose and the molecular players involved in Callose metabolism, and provides new insight into the mechanisms maintaining plasmodesmal Callose homeostasis.
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Callose synthesis in higher plants
Plant Signaling & Behavior, 2009Co-Authors: Xiongyan Chen, Jae-yean KimAbstract:Callose is a polysaccharide in the form of β-1,3-glucan with some β-1,6-branches and it exists in the cell walls of a wide variety of higher plants. Callose plays important roles during a variety of processes in plant development and/or in response to multiple biotic and abiotic stresses. It is now generally believed that Callose is produced by Callose synthases and that it is degraded by β-1,3-glucanases. Despite the importance of Callose in plants, we have only recently begun to elucidate the molecular mechanism of its synthesis. Molecular and genetic studies in Arabidopsis have identified a set of genes that are involved in the biosynthesis and degradation of Callose. In this mini-review, we highlight recent progress in understanding Callose biosynthesis and degradation and discuss the future challenges of unraveling the mechanism(s) by which Callose synthase operate.
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the arabidopsis Callose synthase gene gsl8 is required for cytokinesis and cell patterning
Plant Physiology, 2009Co-Authors: Xiongyan Chen, Lin Liu, Eunkyoung Lee, Xiao Han, Yeonggil Rim, Hyosub Chu, Seonwon Kim, Fred D Sack, Jae-yean KimAbstract:Cytokinesis is the division of the cytoplasm and its separation into two daughter cells. Cell plate growth and cytokinesis appear to require Callose, but direct functional evidence is still lacking. To determine the role of Callose and its synthesis during cytokinesis, we identified and characterized mutants in many members of the GLUCAN SYNTHASE-LIKE (GSL; or Callose SYNTHASE) gene family in Arabidopsis (Arabidopsis thaliana). Most gsl mutants (gsl1–gsl7, gsl9, gsl11, and gsl12) exhibited roughly normal seedling growth and development. However, mutations in GSL8, which were previously reported to be gametophytic lethal, were found to produce seedlings with pleiotropic defects during embryogenesis and early vegetative growth. We found cell wall stubs, two nuclei in one cell, and other defects in cell division in homozygous gsl8 insertional alleles. In addition, gsl8 mutants and inducible RNA interference lines of GSL8 showed reduced Callose deposition at cell plates and/or new cell walls. Together, these data show that the GSL8 gene encodes a putative Callose synthase required for cytokinesis and seedling maturation. In addition, gsl8 mutants disrupt cellular and tissue-level patterning, as shown by the presence of clusters of stomata in direct contact and by islands of excessive cell proliferation in the developing epidermis. Thus, GSL8 is required for patterning as well as cytokinesis during Arabidopsis development.
