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Marie Barberon - One of the best experts on this subject based on the ideXlab platform.
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extracellular membrane tubules involved in suberin deposition in plant cell walls
bioRxiv, 2021Co-Authors: De Bellis D., Marie Barberon, Peter Marhavý, Niko Geldner, Lothar Kalmbach, Jean DaraspeAbstract:Suberin is a fundamental plant biopolymer, found in protective tissues, such as seed coats, exodermis and endodermis of roots, the outer layers of stems and roots with secondary growth, as well as in wound-induced tissues. Its presence allows organs to resist various environmental stresses, such as pathogen attack, drought or excessive salt concentrations. Suberin is a mostly aliphatic polyester of long-chain fatty acids and alcohols, often co-occurring with lignin-like polymers in the same cells. Most suberizing cells appear to deposit suberin in the form of lamellae just outside of the plasma membrane, below the primary cell wall. The monomeric precursors of suberin are thought to be glycerated fatty acids, synthesized at the endoplasmic reticulum. However, it has remained obscure how these monomers are transported outside of the cell, where they will be polymerized to form suberin lamellae. Here, we demonstrate that extracellular vesicular-tubular structures accumulate specifically in suberizing cells. By employing various, independent mutational and hormonal challenges, known to affect Suberization in distinct ways, we demonstrate that their presence correlates perfectly with root Suberization. Surprisingly, no endosomal compartment marker showed any conspicuous changes upon induction of Suberization, suggesting that this compartment might not derive from endosomal multi-vesicular bodies, but possibly form directly from endoplasmic reticulum subdomains. Consistent with this, we could block formation of both, suberin deposition and vesicle accumulation by a pharmacogenetic manipulation affecting early steps in the secretory pathway. Whereas many previous reports have described extracellular vesicle occurrence in the context of biotic interactions, our results suggest a developmental role for extracellular vesicles in suberin formation. One Sentence SummarySuberin lamellae formation is associated with extracellular membrane tubules.
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Regulation of a plant aquaporin by a Casparian strip membrane domain protein-like.
Plant Cell & Environment, 2019Co-Authors: Chloé Champeyroux, Marie Barberon, Jorge Bellati, Christophe Maurel, Valerie Rofidal, Veronique SantoniAbstract:The absorption of soil water by roots allows plants to maintain their water status. At the endodermis, water transport can be affected by initial formation of a Casparian strip and further deposition of suberin lamellas and regulated by the function of aquaporins. Four Casparian strip membrane domain protein-like (CASPL; CASPL1B1, CASPL1B2, CASPL1D1, and CASPL1D2) were previously shown to interact with PIP2;1. The present work shows that CASPL1B1, CASPL1B2, and CASPL1D2 are exclusively expressed in suberized endodermal cells, suggesting a cell-specific role in Suberization and/or water transport regulation. When compared with wild-type plants, and by contrast to caspl1b1*caspl1b2 double loss of function, caspl1d1*caspl1d2 double mutants showed, in some control or NaCl stress experiments and not upon abscisic acid (ABA) treatment, a weak enlargement of the continuous Suberization zone. None of the mutants showed root hydraulic conductivity (Lpr ) phenotype, whether in control, NaCl, or ABA treatment conditions. The data suggest a slight negative role for CASPL1D1 and CASPL1D2 in Suberization under control or salt stress conditions, with no major impact on whole root transport functions. At the molecular level, CASPL1B1 was able to physically interact with PIP2;1 and potentially could influence the regulation of aquaporins by acting on their phosphorylated form.
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Regulation of a plant aquaporin by a Casparian strip membrane domain protein-like
Plant Cell and Environment, 2019Co-Authors: Chloé Champeyroux, Marie Barberon, Jorge Bellati, Christophe Maurel, Valerie Rofidal, Veronique SantoniAbstract:The absorption of soil water by roots allows plants to maintain their water status. At the endodermis, water transport can be affected by initial formation of a Casparian strip, and further deposition of suberin lamellas and regulated by the function of aquaporins. Four Casparian strip membrane domain protein-like (CASPL) (CASPL1B1, CASPL1B2, CASPL1D1 and CASPL1D2) were previously shown to interact with PIP2;1, (Bellati et al. 2016). The present work shows that CASPL1B1, CASPL1B2 and CASPL1D2 are exclusively expressed in suberized endodermal cells, suggesting a cell-specific role in Suberization and/or water transport regulation. When compared to wild-type plants, and by contrast to caspl1b1*caspl1b2 double loss-of-function, caspl1d1*caspl1d2 double mutants showed, in some control or NaCl stress experiments and not upon ABA treatment a weak enlargement of the continuous Suberization zone. None of the mutants showed root hydraulic conductivity (Lpr ) phenotype, whether in control, NaCl or ABA treatment conditions. The data suggest a slight negative role for CASPL1D1 and CASPL1D2 in Suberization under control or salt stress conditions, with no major impact on whole root transport functions. At the molecular level, CASPL1B1 was able to physically interact with PIP2;1, and potentially could influence the regulation of aquaporins by acting on their phosphorylated form.
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adaptation of root function by nutrient induced plasticity of endodermal differentiation
Cell, 2016Co-Authors: Marie Barberon, Tonni Grube Andersen, Joop E M Vermeer, Damien De Bellis, Peng Wang, Sadaf Naseer, Bruno M Humbel, Christiane Nawrath, Junpei Takano, David E. SaltAbstract:Plant roots forage the soil for minerals whose concentrations can be orders of magnitude away from those required for plant cell function. Selective uptake in multicellular organisms critically requires epithelia with extracellular diffusion barriers. In plants, such a barrier is provided by the endodermis and its Casparian strips--cell wall impregnations analogous to animal tight and adherens junctions. Interestingly, the endodermis undergoes secondary differentiation, becoming coated with hydrophobic suberin, presumably switching from an actively absorbing to a protective epithelium. Here, we show that Suberization responds to a wide range of nutrient stresses, mediated by the stress hormones abscisic acid and ethylene. We reveal a striking ability of the root to not only regulate synthesis of suberin, but also selectively degrade it in response to ethylene. Finally, we demonstrate that changes in Suberization constitute physiologically relevant, adaptive responses, pointing to a pivotal role of the endodermal membrane in nutrient homeostasis.
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Suberization-the second life of an endodermal cell
Current Opinion in Plant Biology, 2015Co-Authors: Tonni Grube Andersen, Marie Barberon, Niko GeldnerAbstract:The endodermis is the innermost cortical cell layer that surrounds the central vasculature and deposits an apoplastic diffusion barrier known as the Casparian strip. Although discovered 150 years ago, the underlying mechanisms responsible for formation of the Casparian strips have only recently been investigated. However, the fate of the endodermal cell goes further than formation of Casparian strips as they undergo a second level of differentiation, defined by deposition of suberin as a secondary cell wall. The presence and function of endodermal suberin in root barriers has remained enigmatic, as its role in barrier formation is not clear, especially in respect to the already existing Casparian strips. In this review, we present recent advances in the understanding of suberin synthesis, transport to the secondary cell wall, developmental features and functions. We focus on some of the major unknown questions revolving the function of endodermal suberin, which we now have the means to investigate. We further provide thoughts on how this knowledge might expand our current models on the developmental and physiological adaptation of root in response to the environment.
Veronique Santoni - One of the best experts on this subject based on the ideXlab platform.
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Regulation of a plant aquaporin by a Casparian strip membrane domain protein-like.
Plant Cell & Environment, 2019Co-Authors: Chloé Champeyroux, Marie Barberon, Jorge Bellati, Christophe Maurel, Valerie Rofidal, Veronique SantoniAbstract:The absorption of soil water by roots allows plants to maintain their water status. At the endodermis, water transport can be affected by initial formation of a Casparian strip and further deposition of suberin lamellas and regulated by the function of aquaporins. Four Casparian strip membrane domain protein-like (CASPL; CASPL1B1, CASPL1B2, CASPL1D1, and CASPL1D2) were previously shown to interact with PIP2;1. The present work shows that CASPL1B1, CASPL1B2, and CASPL1D2 are exclusively expressed in suberized endodermal cells, suggesting a cell-specific role in Suberization and/or water transport regulation. When compared with wild-type plants, and by contrast to caspl1b1*caspl1b2 double loss of function, caspl1d1*caspl1d2 double mutants showed, in some control or NaCl stress experiments and not upon abscisic acid (ABA) treatment, a weak enlargement of the continuous Suberization zone. None of the mutants showed root hydraulic conductivity (Lpr ) phenotype, whether in control, NaCl, or ABA treatment conditions. The data suggest a slight negative role for CASPL1D1 and CASPL1D2 in Suberization under control or salt stress conditions, with no major impact on whole root transport functions. At the molecular level, CASPL1B1 was able to physically interact with PIP2;1 and potentially could influence the regulation of aquaporins by acting on their phosphorylated form.
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Regulation of a plant aquaporin by a Casparian strip membrane domain protein-like
Plant Cell and Environment, 2019Co-Authors: Chloé Champeyroux, Marie Barberon, Jorge Bellati, Christophe Maurel, Valerie Rofidal, Veronique SantoniAbstract:The absorption of soil water by roots allows plants to maintain their water status. At the endodermis, water transport can be affected by initial formation of a Casparian strip, and further deposition of suberin lamellas and regulated by the function of aquaporins. Four Casparian strip membrane domain protein-like (CASPL) (CASPL1B1, CASPL1B2, CASPL1D1 and CASPL1D2) were previously shown to interact with PIP2;1, (Bellati et al. 2016). The present work shows that CASPL1B1, CASPL1B2 and CASPL1D2 are exclusively expressed in suberized endodermal cells, suggesting a cell-specific role in Suberization and/or water transport regulation. When compared to wild-type plants, and by contrast to caspl1b1*caspl1b2 double loss-of-function, caspl1d1*caspl1d2 double mutants showed, in some control or NaCl stress experiments and not upon ABA treatment a weak enlargement of the continuous Suberization zone. None of the mutants showed root hydraulic conductivity (Lpr ) phenotype, whether in control, NaCl or ABA treatment conditions. The data suggest a slight negative role for CASPL1D1 and CASPL1D2 in Suberization under control or salt stress conditions, with no major impact on whole root transport functions. At the molecular level, CASPL1B1 was able to physically interact with PIP2;1, and potentially could influence the regulation of aquaporins by acting on their phosphorylated form.
Niko Geldner - One of the best experts on this subject based on the ideXlab platform.
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extracellular membrane tubules involved in suberin deposition in plant cell walls
bioRxiv, 2021Co-Authors: De Bellis D., Marie Barberon, Peter Marhavý, Niko Geldner, Lothar Kalmbach, Jean DaraspeAbstract:Suberin is a fundamental plant biopolymer, found in protective tissues, such as seed coats, exodermis and endodermis of roots, the outer layers of stems and roots with secondary growth, as well as in wound-induced tissues. Its presence allows organs to resist various environmental stresses, such as pathogen attack, drought or excessive salt concentrations. Suberin is a mostly aliphatic polyester of long-chain fatty acids and alcohols, often co-occurring with lignin-like polymers in the same cells. Most suberizing cells appear to deposit suberin in the form of lamellae just outside of the plasma membrane, below the primary cell wall. The monomeric precursors of suberin are thought to be glycerated fatty acids, synthesized at the endoplasmic reticulum. However, it has remained obscure how these monomers are transported outside of the cell, where they will be polymerized to form suberin lamellae. Here, we demonstrate that extracellular vesicular-tubular structures accumulate specifically in suberizing cells. By employing various, independent mutational and hormonal challenges, known to affect Suberization in distinct ways, we demonstrate that their presence correlates perfectly with root Suberization. Surprisingly, no endosomal compartment marker showed any conspicuous changes upon induction of Suberization, suggesting that this compartment might not derive from endosomal multi-vesicular bodies, but possibly form directly from endoplasmic reticulum subdomains. Consistent with this, we could block formation of both, suberin deposition and vesicle accumulation by a pharmacogenetic manipulation affecting early steps in the secretory pathway. Whereas many previous reports have described extracellular vesicle occurrence in the context of biotic interactions, our results suggest a developmental role for extracellular vesicles in suberin formation. One Sentence SummarySuberin lamellae formation is associated with extracellular membrane tubules.
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root endodermal barrier system contributes to defence against plant parasitic cyst and root knot nematodes
Plant Journal, 2019Co-Authors: Julia Holbein, Rochus Franke, Lukas Schreiber, Peter Marhavý, Satoshi Fujita, M Gorecka, Miroslaw Sobczak, Niko Geldner, Florian M W Grundler, Shahid SiddiqueAbstract:Plant-parasitic nematodes (PPNs) cause tremendous yield losses worldwide in almost all economically important crops. The agriculturally most important PPNs belong to a small group of root-infecting sedentary endoparasites that includes cyst and root-knot nematodes. Both cyst and root-knot nematodes induce specialized long-term feeding structures in root vasculature from which they obtain their nutrients. A specialized cell layer in roots called the endodermis, which has cell walls reinforced with suberin deposits and a lignin-based Casparian strip (CS), protects the vascular cylinder against abiotic and biotic threats. To date, the role of the endodermis, and especially of suberin and the CS, during plant-nematode interactions was largely unknown. Here, we analyzed the role of suberin and CS during interaction between Arabidopsis plants and two sedentary root-parasitic nematode species, the cyst nematode Heterodera schachtii and the root-knot nematode Meloidogyne incognita. We found that nematode infection damages the endodermis leading to the activation of suberin biosynthesis genes at nematode infection sites. Although feeding sites induced by both cyst and root-knot nematodes are surrounded by endodermis during early stages of infection, the endodermis is degraded during later stages of feeding site development, indicating periderm formation or ectopic Suberization of adjacent tissue. Chemical suberin analysis showed a characteristic suberin composition resembling peridermal suberin in nematode-infected tissue. Notably, infection assays using Arabidopsis lines with CS defects and impaired compensatory Suberization, revealed that the CS and Suberization impact nematode infectivity and feeding site size. Taken together, our work establishes the role of the endodermal barrier system in defence against a soil-borne pathogen.
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Diffusible repression of cytokinin signalling produces endodermal symmetry and passage cells
Nature, 2018Co-Authors: Tonni Grube Andersen, Joop E M Vermeer, Sadaf Naseer, Robertas Ursache, Brecht Wybouw, Wouter Smet, Bert De Rybel, Niko GeldnerAbstract:In vascular plants, the root endodermis surrounds the central vasculature as a protective sheath that is analogous to the polarized epithelium in animals, and contains ring-shaped Casparian strips that restrict diffusion. After an initial lag phase, individual endodermal cells suberize in an apparently random fashion to produce 'patchy' Suberization that eventually generates a zone of continuous suberin deposition. Casparian strips and suberin lamellae affect paracellular and transcellular transport, respectively. Most angiosperms maintain some isolated cells in an unsuberized state as so-called 'passage cells', which have previously been suggested to enable uptake across an otherwise-impermeable endodermal barrier. Here we demonstrate that these passage cells are late emanations of a meristematic patterning process that reads out the underlying non-radial symmetry of the vasculature. This process is mediated by the non-cell-autonomous repression of cytokinin signalling in the root meristem, and leads to distinct phloem- and xylem-pole-associated endodermal cells. The latter cells can resist abscisic acid-dependent Suberization to produce passage cells. Our data further demonstrate that, during meristematic patterning, xylem-pole-associated endodermal cells can dynamically alter passage-cell numbers in response to nutrient status, and that passage cells express transporters and locally affect the expression of transporters in adjacent cortical cells.
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Role of LOTR1 in Nutrient Transport through Organization of Spatial Distribution of Root Endodermal Barriers
Current Biology, 2017Co-Authors: Takehiro Kamiya, John Danku, Lothar Kalmbach, David E. Salt, Mutsumi Yamagami, Katsushi Yamaguchi, Shuji Shigenobu, Shinichiro Sawa, Niko GeldnerAbstract:The formation of Casparian strips and suberin lamellae at the endodermis limits the free diffusion of nutrients and harmful substances via the apoplastic space between the soil solution and the stele in roots [1–3]. Casparian strips are ring-like lignin polymers deposited in the middle of anticlinal cellwalls between endodermal cells and fill the gap between them [4–6]. Suberin lamellae are glycerolipid polymers covering the endodermal cells and likely function as a barrier to limit transmembrane movement of apoplastic solutes into the endodermal cells [7, 8].However, the current knowledge on the formation of these two distinct endodermal barriers and their regulatory role in nutrient transport is still limited. Here, we identify an uncharacterized gene,LOTR1, essential for Casparian strip formation in Arabidopsis thaliana. The lotr1 mutants display altered localization of CASP1, an essential protein for Casparian strip formation [9], disrupted Casparian strips, ectopic Suberization of endodermal cells, and low accumulation of shoot calcium (Ca). Degradation by expression of a suberin-degrading enzyme in the mutants revealed that the ectopic Suberization at the endodermal cells limits Ca transport through the transmembrane pathway, thereby causing reduced Ca delivery to the shoot. Moreover, analysis of the mutants showed that suberin lamellae function as an apoplastic diffusion barrier to the stele at sites of lateral root emergence where Casparian strips are disrupted. Our findings suggest that the transmembrane pathway through unsuberized endodermal cells, rather than the sites of lateral root emergence,mediates the transport of apoplastic substances such as Ca into the xylem.
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Suberization-the second life of an endodermal cell
Current Opinion in Plant Biology, 2015Co-Authors: Tonni Grube Andersen, Marie Barberon, Niko GeldnerAbstract:The endodermis is the innermost cortical cell layer that surrounds the central vasculature and deposits an apoplastic diffusion barrier known as the Casparian strip. Although discovered 150 years ago, the underlying mechanisms responsible for formation of the Casparian strips have only recently been investigated. However, the fate of the endodermal cell goes further than formation of Casparian strips as they undergo a second level of differentiation, defined by deposition of suberin as a secondary cell wall. The presence and function of endodermal suberin in root barriers has remained enigmatic, as its role in barrier formation is not clear, especially in respect to the already existing Casparian strips. In this review, we present recent advances in the understanding of suberin synthesis, transport to the secondary cell wall, developmental features and functions. We focus on some of the major unknown questions revolving the function of endodermal suberin, which we now have the means to investigate. We further provide thoughts on how this knowledge might expand our current models on the developmental and physiological adaptation of root in response to the environment.
Chloé Champeyroux - One of the best experts on this subject based on the ideXlab platform.
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Regulation of a plant aquaporin by a Casparian strip membrane domain protein-like.
Plant Cell & Environment, 2019Co-Authors: Chloé Champeyroux, Marie Barberon, Jorge Bellati, Christophe Maurel, Valerie Rofidal, Veronique SantoniAbstract:The absorption of soil water by roots allows plants to maintain their water status. At the endodermis, water transport can be affected by initial formation of a Casparian strip and further deposition of suberin lamellas and regulated by the function of aquaporins. Four Casparian strip membrane domain protein-like (CASPL; CASPL1B1, CASPL1B2, CASPL1D1, and CASPL1D2) were previously shown to interact with PIP2;1. The present work shows that CASPL1B1, CASPL1B2, and CASPL1D2 are exclusively expressed in suberized endodermal cells, suggesting a cell-specific role in Suberization and/or water transport regulation. When compared with wild-type plants, and by contrast to caspl1b1*caspl1b2 double loss of function, caspl1d1*caspl1d2 double mutants showed, in some control or NaCl stress experiments and not upon abscisic acid (ABA) treatment, a weak enlargement of the continuous Suberization zone. None of the mutants showed root hydraulic conductivity (Lpr ) phenotype, whether in control, NaCl, or ABA treatment conditions. The data suggest a slight negative role for CASPL1D1 and CASPL1D2 in Suberization under control or salt stress conditions, with no major impact on whole root transport functions. At the molecular level, CASPL1B1 was able to physically interact with PIP2;1 and potentially could influence the regulation of aquaporins by acting on their phosphorylated form.
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Regulation of a plant aquaporin by a Casparian strip membrane domain protein-like
Plant Cell and Environment, 2019Co-Authors: Chloé Champeyroux, Marie Barberon, Jorge Bellati, Christophe Maurel, Valerie Rofidal, Veronique SantoniAbstract:The absorption of soil water by roots allows plants to maintain their water status. At the endodermis, water transport can be affected by initial formation of a Casparian strip, and further deposition of suberin lamellas and regulated by the function of aquaporins. Four Casparian strip membrane domain protein-like (CASPL) (CASPL1B1, CASPL1B2, CASPL1D1 and CASPL1D2) were previously shown to interact with PIP2;1, (Bellati et al. 2016). The present work shows that CASPL1B1, CASPL1B2 and CASPL1D2 are exclusively expressed in suberized endodermal cells, suggesting a cell-specific role in Suberization and/or water transport regulation. When compared to wild-type plants, and by contrast to caspl1b1*caspl1b2 double loss-of-function, caspl1d1*caspl1d2 double mutants showed, in some control or NaCl stress experiments and not upon ABA treatment a weak enlargement of the continuous Suberization zone. None of the mutants showed root hydraulic conductivity (Lpr ) phenotype, whether in control, NaCl or ABA treatment conditions. The data suggest a slight negative role for CASPL1D1 and CASPL1D2 in Suberization under control or salt stress conditions, with no major impact on whole root transport functions. At the molecular level, CASPL1B1 was able to physically interact with PIP2;1, and potentially could influence the regulation of aquaporins by acting on their phosphorylated form.
Edward C Lulai - One of the best experts on this subject based on the ideXlab platform.
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wound induced Suberization genes are differentially expressed spatially and temporally during closing layer and wound periderm formation
Postharvest Biology and Technology, 2014Co-Authors: Edward C Lulai, Jonathan D NeubauerAbstract:Abstract Potato tuber ( Solanum tuberosum L.) wounds incurred at harvest and upon seed cutting require rapid Suberization as a major part of the healing process to prevent infection and desiccation. However, little is known about the induction and expression of genes that are essential for these processes and in particular to the two major stages of wound-induced Suberization, i.e. closing layer formation and wound periderm formation. The objectives of this research were to address these needs by determining the effects of wounding on the induction and expression profiles of specific genes involved in wound-induced Suberization in potato tuber ( S. tuberosum L.) during the initiation and completion of closing layer formation and wound periderm formation. Although both stages critically involve Suberization, there are significant differences between the two processes. Closing layer development requires rapid Suberization of existing parenchyma cells bordering the wound surface to provide the initial protective barrier for the wound. Wound periderm development occurs later, i.e. after completion of closing layer formation, and requires development of a wound phellogen layer which mediates the formation of highly organized files of suberized wound-phellem cells that provide a more durable protective barrier for the tuber. The processes delineating these two separate stages of wound-induced Suberization are poorly understood. This research shows that, unlike some wound responding genes such as phenylalanine ammonia lyase ( StPAL-1 ) and anionic peroxidase ( StPrx ), certain genes that are specifically involved in both of these processes do not remain uniformly up-regulated during the two stages of healing (i.e. StTHT encoding Hydroxycinnamoyl-CoA:tyramine N-(hydroxycinnamoyl)transferase, StFHT encoding a fatty ω-hydroxyacid/fatty alcohol hydroxycinnamoyl transferase, StKCS6 encoding a 3-ketoacyl-CoA synthase, StFAOH encoding a fatty acid ω-hydroxylase and StGPAT5 encoding a protein with acyl-CoA:glycerol-3-phosphate acyltransferase). Instead, they are up-regulated during closing layer formation; i.e. starting by ca. 1 d after wounding, but then slightly down-regulated or pause near completion of the closing layer (ca. 5–6 d) and then again up-regulated as wound periderm development is fully initiated (ca. 7 d) and down-regulated near completion (ca. 28 d after wounding). This differential in the expression profile, i.e. decrease between stages, was not anticipated and may be the first demonstration of measurable changes of any sort of biological flux as wound induced Suberization transitions from closing layer to wound periderm development. Results were repeated using minitubers from two different crop years and demonstrate that these processes are separate, but coupled in some yet to be determined fashion. The biology of this differential expression is important because of the roles closing layer and wound periderm development play in protecting the tuber from disease and other challenges.
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non wound induced Suberization of tuber parenchyma cells a physiological response to the wilt disease pathogen verticillium dahliae
American Journal of Potato Research, 2005Co-Authors: Edward C LulaiAbstract:Verticillium spp. wilt pathogens enter the root and eventually penetrate xylem vessels of the plant where they can spread into the vascular tissue of the potato tuber. Infected tuber vessel elements often become discolored creating a serious internal tuber quality defect that prevents sale of raw product to its primary market. Despite the costly losses and disease issues created by these infections, the physiological responses to colonization of tuber vessel elements are poorly described, and a model system to study these responses in the laboratory has not been developed. The objectives of this research were to develop such a model system by determining if tuber vessel elements could be infiltrated withVerticillium spp. in a laboratory setting and if a detectable physiological response could be elicited and identified. Results demonstrated that tuber vessel elements in the model system could be infiltrated and that infiltration ofVerticillium dahliae Kleb. conidia into these vessel elements induced a Suberization response on the walls of neighboring parenchyma cells. However, the walls of the infiltrated tuber vessel elements did not suberize. A similar Suberization response was found in tubers that had been naturally infected byVerticillium dahliae in the field. The Suberization response was histochemically determined by assessing the accumulation of suberin poly(aliphatics) and poly(phenolics). This process of internal Suberization of tuber parenchyma cells occurred without induction by a wound signal. Consequently, the Suberization signal was derived by introduction of the plant-pathogen into the tuber vessel elements. This simple model system provides a versatile tool to investigate the physiological responses of potato tuber to colonization of vessel elements. This is believed to be the first report for such a physiological response toVerticillium spp. in potato tuber.
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the involvement of ethylene in wound induced Suberization of potato tuber solanum tuberosum l a critical assessment
Postharvest Biology and Technology, 2004Co-Authors: Edward C Lulai, Jeffrey C SuttleAbstract:Abstract The determination of hormonal requirements for wound-induced Suberization is important in developing new approaches and future postharvest technologies to control various wound-related disease and defect problems in potato tuber (Solanum tuberosum L.). Although, the hormone ethylene has been shown to be involved in various kinds of plant stress, including certain wound responses, its role in Suberization had not been determined. The role of ethylene in wound-induced Suberization of potato tuber was examined over a 9-day wound-healing period, using a variety of ethylene biosynthesis and action inhibitors. Ethylene evolution was stimulated by wounding and reached a maximum 2–3 days after tuber wounding, and then gradually declined. The competitive inhibitor of ethylene action, 2,5-norbornadiene, had no effect on the wound-induced accumulation of suberin polyphenolic(s) (SPP). Similarly, the ethylene antagonist 1-methylcyclopropene (1-MCP) had no apparent effect on wound-induced accumulation of SPPs or on the accumulation of suberin polyaliphatic(s) (SPA). Treatment of tubers with ethylene, applied either before or after wounding, had no effect on the induction or accumulation of either suberin biopolymer. Treatment with the ethylene biosynthesis inhibitor, aminoethoxyvinylglycine (AVG), inhibited wound-induced ethylene production by ca. 90%, but did not affect wound-induced Suberization. Collectively, these results indicate that, although increased ethylene evolution is part of the tuber wound response, ethylene is not required for wound-induced Suberization of the closing layer (Suberization of existing cells at the wound surface) during the first 2–4 days of wound-healing or subsequent Suberization of phellem cells (between 4 and 9 days) created by the wound-induced formation of the phellogen. These results are important in determining the mechanisms regulating Suberization and in assuring that wound-induced Suberization is not inhibited with the application of new technologies that effectively control various ethylene mediated processes in vegetables and fruit.
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differential deposition of suberin phenolic and aliphatic domains and their roles in resistance to infection during potato tuber solanum tuberosum l wound healing
Physiological and Molecular Plant Pathology, 1998Co-Authors: Edward C Lulai, D L CorsiniAbstract:Abstract Rapid Suberization of wounded potato tubers is critical in avoiding infection byErwinia carotovorasubsp.carotovora(a causal organism of bacterial soft rot) andFusarium sambucinum(a causal organism of fungal dry rot) in cut seed and stored potatoes. However, until now the reason for the differential development of resistance to bacterial and then fungal penetration during Suberization has not been shown to be related to the differential deposition of the two major suberin components (phenolic and aliphatic domains) during wound-healing. Tubers of four varieties of diverse genetic background were wounded and inoculated withE. carotovorasubsp.carotovorathroughout a 5-day time course andF. sambucinumthroughout an 11-day time course during wound-healing (18 °C and 98% RH). During wound-healing, the tubers were examined at the cellular level for deposition of suberin phenolic and aliphatic domains. The percentage of inoculated tubers which became infected was determined for each wound-healing time point and was related to the deposition of suberin phenolic and aliphatic domains. Total resistance to infection byE. carotovorasubsp.carotovoraoccurred after the completion of phenolic deposition on the outer tangential wall of the first layer of cells (2–3 days). However, this suberin phenolic matrix offered no resistance to fungal infection byF. sambucinumeven after phenolic deposition was complete on adjoining radial and inner tangential cell walls of the first layer of cells. Resistance to fungal infection did not begin to develop until after deposition of the suberin aliphatic domain was initiated. Total resistance to fungal infection was attained after completion of deposition of the suberin aliphatic domain within the first layer of suberizing cells (5–7 days). These results indicate that the suberin phenolic domain provides resistance to infection byE. carotovorasubsp.carotovorabut not infection byF. sambucinum.They further suggest that deposition of the suberin aliphatic domain is responsible for final resistance to infection byF. sambucinum.This is believed to be the first evidence indicating separate depositional patterns, at the cellular level, for the two major domains of suberin and separate roles for each of these domains in the development of resistance to bacterial and fungal infection during Suberization.
