The Experts below are selected from a list of 3666 Experts worldwide ranked by ideXlab platform
Hiroo Fukuda - One of the best experts on this subject based on the ideXlab platform.
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Transient transformation and RNA silencing in Zinnia tracheary element differentiating cell cultures
The Plant journal : for cell and molecular biology, 2007Co-Authors: Satoshi Endo, Edouard Pesquet, Deborah Goffner, Tashiro, Hideo Kuriyama, Hiroo Fukuda, Taku DemuraAbstract:The Zinnia elegans cell culture system is a robust and physiologically relevant in vitro system for the study of xylem formation. Freshly isolated mesophyll cells of Zinnia can be hormonally induced to semisynchronously transdifferentiate into tracheary elements (TEs). Although the system has proven to be valuable, its utility is diminished by the lack of an efficient transformation protocol. We herein present a novel method to introduce DNA/RNA efficiently into Zinnia cells by electroporation-based transient transformation. Using reporter gene plasmids, we optimized the system for efficiency of transformation and ability for the transformed cells to transdifferentiate into TEs. Optimal conditions included a partial digestion of the cell walls by pectolyase, a low voltage and high capacitance electrical pulse and an optimal medium to maintain cell viability during transformation. Beyond the simple expression of a reporter protein in Zinnia cells, we extended our protocol to subcellular protein targeting, simultaneous co-expression of several reporter proteins and promoter-activity monitoring during TE differentiation. Most importantly, we tested the system for double-stranded RNA (dsRNA)-induced RNA silencing. By introducing in vitro-synthesized dsRNAs, we were able to phenocopy the Arabidopsis cellulose synthase (CesA) mutants that had defects in secondary cell-wall synthesis. Suppressing the expression ofZinnia CesA homologues resulted in an increase of abnormal TEs with aberrant secondary walls. Our electroporation-based transient transformation protocol provides the suite of tools long required for functional analysis and developmental studies at single cell levels.
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hd zip iii homeobox genes that include a novel member zehb 13 Zinnia athb 15 arabidopsis are involved in procambium and xylem cell differentiation
Plant and Cell Physiology, 2003Co-Authors: Kyoko Ohashiito, Hiroo FukudaAbstract:HD-Zip III homeobox genes are known to be essential transcriptional factors for vascular development. To further understand the relation of HD-Zip III genes in vascular differentiation, we isolated a new member of the HD-Zip III genes, ZeHB-13, as a Zinnia homolog of ATHB-15, and then characterized the expression profile using a Zinnia xylogenic cell culture and Zinnia plants. We compared the accumulation pattern of transcripts for ZeHB-13 and other HD-Zip III genes and suggested that the expression of ZeHB-13 was restricted to the procambium and was not severely suppressed by brassinazole, an inhibitor of brassinosteroid biosynthesis, unlike other HD-Zip III genes. We also characterized its Arabidopsis counterpart, ATHB-15. A histochemical promoter analysis using ATHB-15::GUS transgenic Arabidopsis plants indicated that ATHB-15 was active specifically in the procambium. These results strongly suggest that ZeHB-13/ATHB-15 is a pivotal transcriptional regulator responsible for early vascular development. Based on these results, we will discuss the regulation of xylem development in light of the functions of HD-Zip III members and brassinosteroids.
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promotion of transcript accumulation of novel Zinnia immature xylem specific hd zip iii homeobox genes by brassinosteroids
Plant and Cell Physiology, 2002Co-Authors: Kyoko Ohashiito, Taku Demura, Hiroo FukudaAbstract:We isolated three novel homeobox genes (ZeHB-10, -11 and -12) from Zinnia elegans to elucidate the molecular mechanism underlying vascular system formation. ZeHB-10, -11 and -12 encode for HD-Zip proteins of the class III to which Arabidopsis Athb-8, -9, -14, -15 and IFL1 belong. In situ hybridization analysis demonstrated that the ZeHB-10, -11 and -12 mRNAs accumulated preferentially in procambium and immature xylem cells in 14-day-old plants. Transcripts for the three genes also accumulated in cultured Zinnia cells in a xylogenesis-specific manner. The accumulation of transcripts for all of ZeHB-10, -11 and -12 in cultured Zinnia cells was suppressed strongly by uniconazole, an inhibitor of brassinosteroid synthesis, and such suppression was reversed by the addition of brassinolide, a biologically active brassinosteroid. Thus the expression of ZeHB-10, -11 and -12 may be regulated by endogenous levels of brassinosteroids. Taken together with the fact that ZeHB-10, -11 and -12 proteins can bind to each other in yeast, the roles of HD-Zip III genes in vascular development are discussed.
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differential expression of three genes for different rβ tubulin isotypes during the initial culture of Zinnia mesophyll cells that divide and differentiate into tracheary elements
Plant and Cell Physiology, 1996Co-Authors: Toshihiko Yoshimura, Taku Demura, Megumi Igarashi, Hiroo FukudaAbstract:Complementary DNA clones for three different beta-tubulin isotypes (ZeTubB1, ZeTubB2 and ZeTubB3) were isolated from a cDNA library generated from RNA of cultured mesophyll cells of Zinnia elegans that were differentiating into tracheary elements and/or dividing. Sequence analysis revealed that the proteins encoded by ZeTubB1 and ZeTubB3 and that encoded by ZeTubB2 were each homologous to two of three groups of beta-tubulin isotypes in Arabidopsis. RNA gel blot analysis of the expression of the ZeTubB transcripts indicated that transcripts that corresponded to each clone were differently expressed during culture of Zinnia mesophyll cells. In particular, the level of expression of ZeTubB1 and ZeTubB3 transcripts increased rapidly prior to cell division and secondary wall formation, and such expression was promoted by combinations of auxin and cytokinin that induced tracheary element differentiation as well as cell division. Results of an in situ hybridization experiment with an antisense RNA probe derived from ZeTubB1 cDNA suggested the preferential expression of ZeTubB transcripts in differentiating xylem cells, as well as in the ground meristem and the procambium, of Zinnia seedlings.
Taku Demura - One of the best experts on this subject based on the ideXlab platform.
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Transient transformation and RNA silencing in Zinnia tracheary element differentiating cell cultures
The Plant journal : for cell and molecular biology, 2007Co-Authors: Satoshi Endo, Edouard Pesquet, Deborah Goffner, Tashiro, Hideo Kuriyama, Hiroo Fukuda, Taku DemuraAbstract:The Zinnia elegans cell culture system is a robust and physiologically relevant in vitro system for the study of xylem formation. Freshly isolated mesophyll cells of Zinnia can be hormonally induced to semisynchronously transdifferentiate into tracheary elements (TEs). Although the system has proven to be valuable, its utility is diminished by the lack of an efficient transformation protocol. We herein present a novel method to introduce DNA/RNA efficiently into Zinnia cells by electroporation-based transient transformation. Using reporter gene plasmids, we optimized the system for efficiency of transformation and ability for the transformed cells to transdifferentiate into TEs. Optimal conditions included a partial digestion of the cell walls by pectolyase, a low voltage and high capacitance electrical pulse and an optimal medium to maintain cell viability during transformation. Beyond the simple expression of a reporter protein in Zinnia cells, we extended our protocol to subcellular protein targeting, simultaneous co-expression of several reporter proteins and promoter-activity monitoring during TE differentiation. Most importantly, we tested the system for double-stranded RNA (dsRNA)-induced RNA silencing. By introducing in vitro-synthesized dsRNAs, we were able to phenocopy the Arabidopsis cellulose synthase (CesA) mutants that had defects in secondary cell-wall synthesis. Suppressing the expression ofZinnia CesA homologues resulted in an increase of abnormal TEs with aberrant secondary walls. Our electroporation-based transient transformation protocol provides the suite of tools long required for functional analysis and developmental studies at single cell levels.
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visualization by comprehensive microarray analysis of gene expression programs during transdifferentiation of mesophyll cells into xylem cells
Proceedings of the National Academy of Sciences of the United States of America, 2002Co-Authors: Taku Demura, Gen Tashiro, Gorou Horiguchi, Naoki Kishimoto, Minoru Kubo, Naoko Matsuoka, Atsushi Minami, Miyo Nagatahiwatashi, Keiko Nakamura, Yoshimichi OkamuraAbstract:Plants have a unique transdifferentiation mechanism by which differentiated cells can initiate a new program of differentiation. We used a comprehensive analysis of gene expression in an in vitro Zinnia (Zinnia elegans L.) culture model system to gather fundamental information about the gene regulation underlying the transdifferentiation of plant cells. In this model, photosynthetic mesophyll cells isolated from Zinnia leaves transdifferentiate into xylem cells in a morphogenic process characterized by features such as secondary-wall formation and programmed cell death. More than 8,000 Zinnia cDNA clones were isolated from an equalized cDNA library prepared from cultured cells transdifferentiating into xylem cells. Microarray analysis using these cDNAs revealed several types of unique gene regulation patterns, including: the transient expression of a set of genes during cell isolation, presumably induced by wounding; a rapid reduction in the expression of photosynthetic genes and the rapid induction of protein synthesis-associated genes during the first stage; the preferential induction of auxin-related genes during the subsequent stage; and the transient induction of genes closely associated with particular morphogenetic events, including cell-wall formation and degradation and programmed cell death during the final stage. This analysis also revealed a number of previously uncharacterized genes encoding proteins that function in signal transduction, such as protein kinases and transcription factors that are expressed in a stage-specific manner. These findings provide new clues to the molecular mechanisms of both plant transdifferentiation and wood formation.
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promotion of transcript accumulation of novel Zinnia immature xylem specific hd zip iii homeobox genes by brassinosteroids
Plant and Cell Physiology, 2002Co-Authors: Kyoko Ohashiito, Taku Demura, Hiroo FukudaAbstract:We isolated three novel homeobox genes (ZeHB-10, -11 and -12) from Zinnia elegans to elucidate the molecular mechanism underlying vascular system formation. ZeHB-10, -11 and -12 encode for HD-Zip proteins of the class III to which Arabidopsis Athb-8, -9, -14, -15 and IFL1 belong. In situ hybridization analysis demonstrated that the ZeHB-10, -11 and -12 mRNAs accumulated preferentially in procambium and immature xylem cells in 14-day-old plants. Transcripts for the three genes also accumulated in cultured Zinnia cells in a xylogenesis-specific manner. The accumulation of transcripts for all of ZeHB-10, -11 and -12 in cultured Zinnia cells was suppressed strongly by uniconazole, an inhibitor of brassinosteroid synthesis, and such suppression was reversed by the addition of brassinolide, a biologically active brassinosteroid. Thus the expression of ZeHB-10, -11 and -12 may be regulated by endogenous levels of brassinosteroids. Taken together with the fact that ZeHB-10, -11 and -12 proteins can bind to each other in yeast, the roles of HD-Zip III genes in vascular development are discussed.
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differential expression of three genes for different rβ tubulin isotypes during the initial culture of Zinnia mesophyll cells that divide and differentiate into tracheary elements
Plant and Cell Physiology, 1996Co-Authors: Toshihiko Yoshimura, Taku Demura, Megumi Igarashi, Hiroo FukudaAbstract:Complementary DNA clones for three different beta-tubulin isotypes (ZeTubB1, ZeTubB2 and ZeTubB3) were isolated from a cDNA library generated from RNA of cultured mesophyll cells of Zinnia elegans that were differentiating into tracheary elements and/or dividing. Sequence analysis revealed that the proteins encoded by ZeTubB1 and ZeTubB3 and that encoded by ZeTubB2 were each homologous to two of three groups of beta-tubulin isotypes in Arabidopsis. RNA gel blot analysis of the expression of the ZeTubB transcripts indicated that transcripts that corresponded to each clone were differently expressed during culture of Zinnia mesophyll cells. In particular, the level of expression of ZeTubB1 and ZeTubB3 transcripts increased rapidly prior to cell division and secondary wall formation, and such expression was promoted by combinations of auxin and cytokinin that induced tracheary element differentiation as well as cell division. Results of an in situ hybridization experiment with an antisense RNA probe derived from ZeTubB1 cDNA suggested the preferential expression of ZeTubB transcripts in differentiating xylem cells, as well as in the ground meristem and the procambium, of Zinnia seedlings.
Kyoko Ohashiito - One of the best experts on this subject based on the ideXlab platform.
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hd zip iii homeobox genes that include a novel member zehb 13 Zinnia athb 15 arabidopsis are involved in procambium and xylem cell differentiation
Plant and Cell Physiology, 2003Co-Authors: Kyoko Ohashiito, Hiroo FukudaAbstract:HD-Zip III homeobox genes are known to be essential transcriptional factors for vascular development. To further understand the relation of HD-Zip III genes in vascular differentiation, we isolated a new member of the HD-Zip III genes, ZeHB-13, as a Zinnia homolog of ATHB-15, and then characterized the expression profile using a Zinnia xylogenic cell culture and Zinnia plants. We compared the accumulation pattern of transcripts for ZeHB-13 and other HD-Zip III genes and suggested that the expression of ZeHB-13 was restricted to the procambium and was not severely suppressed by brassinazole, an inhibitor of brassinosteroid biosynthesis, unlike other HD-Zip III genes. We also characterized its Arabidopsis counterpart, ATHB-15. A histochemical promoter analysis using ATHB-15::GUS transgenic Arabidopsis plants indicated that ATHB-15 was active specifically in the procambium. These results strongly suggest that ZeHB-13/ATHB-15 is a pivotal transcriptional regulator responsible for early vascular development. Based on these results, we will discuss the regulation of xylem development in light of the functions of HD-Zip III members and brassinosteroids.
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promotion of transcript accumulation of novel Zinnia immature xylem specific hd zip iii homeobox genes by brassinosteroids
Plant and Cell Physiology, 2002Co-Authors: Kyoko Ohashiito, Taku Demura, Hiroo FukudaAbstract:We isolated three novel homeobox genes (ZeHB-10, -11 and -12) from Zinnia elegans to elucidate the molecular mechanism underlying vascular system formation. ZeHB-10, -11 and -12 encode for HD-Zip proteins of the class III to which Arabidopsis Athb-8, -9, -14, -15 and IFL1 belong. In situ hybridization analysis demonstrated that the ZeHB-10, -11 and -12 mRNAs accumulated preferentially in procambium and immature xylem cells in 14-day-old plants. Transcripts for the three genes also accumulated in cultured Zinnia cells in a xylogenesis-specific manner. The accumulation of transcripts for all of ZeHB-10, -11 and -12 in cultured Zinnia cells was suppressed strongly by uniconazole, an inhibitor of brassinosteroid synthesis, and such suppression was reversed by the addition of brassinolide, a biologically active brassinosteroid. Thus the expression of ZeHB-10, -11 and -12 may be regulated by endogenous levels of brassinosteroids. Taken together with the fact that ZeHB-10, -11 and -12 proteins can bind to each other in yeast, the roles of HD-Zip III genes in vascular development are discussed.
Edouard Pesquet - One of the best experts on this subject based on the ideXlab platform.
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Transient transformation and RNA silencing in Zinnia tracheary element differentiating cell cultures
The Plant journal : for cell and molecular biology, 2007Co-Authors: Satoshi Endo, Edouard Pesquet, Deborah Goffner, Tashiro, Hideo Kuriyama, Hiroo Fukuda, Taku DemuraAbstract:The Zinnia elegans cell culture system is a robust and physiologically relevant in vitro system for the study of xylem formation. Freshly isolated mesophyll cells of Zinnia can be hormonally induced to semisynchronously transdifferentiate into tracheary elements (TEs). Although the system has proven to be valuable, its utility is diminished by the lack of an efficient transformation protocol. We herein present a novel method to introduce DNA/RNA efficiently into Zinnia cells by electroporation-based transient transformation. Using reporter gene plasmids, we optimized the system for efficiency of transformation and ability for the transformed cells to transdifferentiate into TEs. Optimal conditions included a partial digestion of the cell walls by pectolyase, a low voltage and high capacitance electrical pulse and an optimal medium to maintain cell viability during transformation. Beyond the simple expression of a reporter protein in Zinnia cells, we extended our protocol to subcellular protein targeting, simultaneous co-expression of several reporter proteins and promoter-activity monitoring during TE differentiation. Most importantly, we tested the system for double-stranded RNA (dsRNA)-induced RNA silencing. By introducing in vitro-synthesized dsRNAs, we were able to phenocopy the Arabidopsis cellulose synthase (CesA) mutants that had defects in secondary cell-wall synthesis. Suppressing the expression ofZinnia CesA homologues resulted in an increase of abnormal TEs with aberrant secondary walls. Our electroporation-based transient transformation protocol provides the suite of tools long required for functional analysis and developmental studies at single cell levels.
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galactoglucomannans increase cell population density and alter the protoxylem metaxylem tracheary element ratio in xylogenic cultures of Zinnia
Plant Physiology, 2006Co-Authors: Anna Benovakakosova, Catherine Digonnet, Florence Goubet, Philippe Ranocha, Alain Jauneau, Edouard Pesquet, Odile Barbier, Zhinong Zhang, Peter Capek, Paul DupreeAbstract:Xylogenic cultures of Zinnia (Zinnia elegans) provide a unique opportunity to study signaling pathways of tracheary element (TE) differentiation. In vitro TEs differentiate into either protoxylem (PX)-like TEs characterized by annular/helical secondary wall thickening or metaxylem (MX)-like TEs with reticulate/scalariform/pitted thickening. The factors that determine these different cell fates are largely unknown. We show here that supplementing Zinnia cultures with exogenous galactoglucomannan oligosaccharides (GGMOs) derived from spruce (Picea abies) xylem had two major effects: an increase in cell population density and a decrease in the ratio of PX to MX TEs. In an attempt to link these two effects, the consequence of the plane of cell division on PX-MX differentiation was assessed. Although GGMOs did not affect the plane of cell division per se, they significantly increased the proportion of longitudinally divided cells differentiating into MX. To test the biological significance of these findings, we have determined the presence of mannan-containing oligosaccharides in Zinnia cultures in vitro. Immunoblot assays indicated that β-1,4-mannosyl epitopes accumulate specifically in TE-inductive media. These epitopes were homogeneously distributed within the thickened secondary walls of TEs when the primary cell wall was weakly labeled. Using polysaccharide analysis carbohydrate gel electrophoresis, glucomannans were specifically detected in cell walls of differentiating Zinnia cultures. Finally, Zinnia macroarrays probed with cDNAs from cells cultured in the presence or absence of GGMOs indicated that significantly more genes were down-regulated rather than up-regulated by GGMOs. This study constitutes a major step in the elucidation of signaling mechanisms of PX- and MX-specific genetic programs in Zinnia.
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Galactoglucomannans increase cell population density and alter the protoxylem/metaxylem tracheary element ratio in xylogenic cultures of Zinnia
Plant physiology, 2006Co-Authors: Anna Benová-kákosová, Catherine Digonnet, Florence Goubet, Philippe Ranocha, Alain Jauneau, Edouard Pesquet, Odile Barbier, Zhinong Zhang, Peter Capek, Paul DupreeAbstract:Xylogenic cultures of Zinnia (Zinnia elegans) provide a unique opportunity to study signaling pathways of tracheary element (TE) differentiation. In vitro TEs differentiate into either protoxylem (PX)-like TEs characterized by annular/helical secondary wall thickening or metaxylem (MX)-like TEs with reticulate/scalariform/pitted thickening. The factors that determine these different cell fates are largely unknown. We show here that supplementing Zinnia cultures with exogenous galactoglucomannan oligosaccharides (GGMOs) derived from spruce (Picea abies) xylem had two major effects: an increase in cell population density and a decrease in the ratio of PX to MX TEs. In an attempt to link these two effects, the consequence of the plane of cell division on PX-MX differentiation was assessed. Although GGMOs did not affect the plane of cell division per se, they significantly increased the proportion of longitudinally divided cells differentiating into MX. To test the biological significance of these findings, we have determined the presence of mannan-containing oligosaccharides in Zinnia cultures in vitro. Immunoblot assays indicated that β-1,4-mannosyl epitopes accumulate specifically in TE-inductive media. These epitopes were homogeneously distributed within the thickened secondary walls of TEs when the primary cell wall was weakly labeled. Using polysaccharide analysis carbohydrate gel electrophoresis, glucomannans were specifically detected in cell walls of differentiating Zinnia cultures. Finally, Zinnia macroarrays probed with cDNAs from cells cultured in the presence or absence of GGMOs indicated that significantly more genes were down-regulated rather than up-regulated by GGMOs. This study constitutes a major step in the elucidation of signaling mechanisms of PX- and MX-specific genetic programs in Zinnia.
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Zinnia elegans: the missing link from in vitro tracheary elements to xylem
Physiologia Plantarum, 2003Co-Authors: Edouard Pesquet, Catherine Digonnet, Alain Jauneau, Alain M. Boudet, Magalie Pichon, Deborah GoffnerAbstract:For the last 20 years, in vitro xylogenic cultures of Zinniaelegans have been routinely used to study tracheary element(TE) formation. That said, the precise anatomical relationship between in vitro and in planta xylogenesis in Zinnia has been completely ignored. In order to make this comparison, weprovide herein a much needed description of xylem tissue of the Zinnia plant. Based on the proportions of secondary wall thickenings, the in vitro TE system most closely resembles hypocotyl vasculature. Moreover, we have shown by confocalmicroscopy that vessel-like structures of up to five individual TEs are produced in vitro, suggesting that the formation of multi cellular structures and cell–cell communication during in vitro TE formation are far more extensive than previously suspected. Finally, as more and more genes become available through genomic approaches of Zinnia TEs, it will be necessary to precisely localize them in planta as a first step inelucidating gene function. Our results provide the histological groundwork for this very purpose
Ernst J Woltering - One of the best experts on this subject based on the ideXlab platform.
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Xylogenesis in Zinnia (Zinnia elegans) cell cultures: unravelling the regulatory steps in a complex developmental programmed cell death event
Planta, 2017Co-Authors: Elena T. Iakimova, Ernst J WolteringAbstract:Main conclusion Physiological and molecular studies support the view that xylogenesis can largely be determined as a specific form of vacuolar programmed cell death (PCD). The studies in xylogenic Zinnia cell culture have led to many breakthroughs in xylogenesis research and provided a background for investigations in other experimental models in vitro and in planta . This review discusses the most essential earlier and recent findings on the regulation of xylem elements differentiation and PCD in Zinnia and other xylogenic systems. Xylogenesis (the formation of water conducting vascular tissue) is a paradigm of plant developmental PCD. The xylem vessels are composed of fused tracheary elements (TEs)—dead, hollow cells with patterned lignified secondary cell walls. They result from the differentiation of the procambium and cambium cells and undergo cell death to become functional post - mortem . The TE differentiation proceeds through a well-coordinated sequence of events in which differentiation and the programmed cellular demise are intimately connected. For years a classical experimental model for studies on xylogenesis was the xylogenic Zinnia ( Zinnia elegans ) cell culture derived from leaf mesophyll cells that, upon induction by cytokinin and auxin, transdifferentiate into TEs. This cell system has been proven very efficient for investigations on the regulatory components of xylem differentiation which has led to many discoveries on the mechanisms of xylogenesis. The knowledge gained from this system has potentiated studies in other xylogenic cultures in vitro and in planta . The present review summarises the previous and latest findings on the hormonal and biochemical signalling, metabolic pathways and molecular and gene determinants underlying the regulation of xylem vessels differentiation in Zinnia cell culture. Highlighted are breakthroughs achieved through the use of xylogenic systems from other species and newly introduced tools and analytical approaches to study the processes. The mutual dependence between PCD signalling and the differentiation cascade in the program of TE development is discussed.
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Xylogenesis in Zinnia ( Zinnia elegans ) cell cultures: unravelling the regulatory steps in a complex developmental programmed cell death event
Planta, 2017Co-Authors: Elena T. Iakimova, Ernst J WolteringAbstract:Physiological and molecular studies support the view that xylogenesis can largely be determined as a specific form of vacuolar programmed cell death (PCD). The studies in xylogenic Zinnia cell culture have led to many breakthroughs in xylogenesis research and provided a background for investigations in other experimental models in vitro and in planta . This review discusses the most essential earlier and recent findings on the regulation of xylem elements differentiation and PCD in Zinnia and other xylogenic systems. Xylogenesis (the formation of water conducting vascular tissue) is a paradigm of plant developmental PCD. The xylem vessels are composed of fused tracheary elements (TEs)—dead, hollow cells with patterned lignified secondary cell walls. They result from the differentiation of the procambium and cambium cells and undergo cell death to become functional post-mortem. The TE differentiation proceeds through a well-coordinated sequence of events in which differentiation and the programmed cellular demise are intimately connected. For years a classical experimental model for studies on xylogenesis was the xylogenic Zinnia (Zinnia elegans) cell culture derived from leaf mesophyll cells that, upon induction by cytokinin and auxin, transdifferentiate into TEs. This cell system has been proven very efficient for investigations on the regulatory components of xylem differentiation which has led to many discoveries on the mechanisms of xylogenesis. The knowledge gained from this system has potentiated studies in other xylogenic cultures in vitro and in planta. The present review summarises the previous and latest findings on the hormonal and biochemical signalling, metabolic pathways and molecular and gene determinants underlying the regulation of xylem vessels differentiation in Zinnia cell culture. Highlighted are breakthroughs achieved through the use of xylogenic systems from other species and newly introduced tools and analytical approaches to study the processes. The mutual dependence between PCD signalling and the differentiation cascade in the program of TE development is discussed.
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Establishing in vitro Zinnia elegans cell suspension culture with high tracheary element differentiation
Cell biology international, 2009Co-Authors: Peter Twumasi, Ernst J Woltering, J H N Schel, Wim Van Ieperen, Olaf Van Kooten, Anne Mie C EmonsAbstract:The Zinnia elegans mesophyll cell culture is a useful system for xylogenesis studies. The system is associated with highly synchronous tracheary element (TE) differentiation, making it more suitable for molecular studies requiring larger amounts of molecular isolates, such as mRNA and proteins and for studying cellulose synthesis. There is, however, the problem of non-uniformity and significant variations in the yields of TEs (%TE). One possible cause for this variability in the %TE could be the lack of a standardized experimental protocol in various research laboratories for establishing the Zinnia culture. Mesophyll cells isolated from the first true leaves of Z. elegans var Envy seedlings of approximately 14 days old were cultured in vitro and differentiated into TEs. The xylogenic culture medium was supplied with 1mg/l each of benzylaminopurine (BA) and alpha-naphthalene acetic acid (NAA). Application of this improved culture method resulted in stable and reproducible amounts of TE as high as 76% in the Zinnia culture. The increase was mainly due to conditioning of the mesophyll cell culture and adjustments of the phytohormonal balance in the cultures. Also, certain biochemical and cytological methods have been shown to reliably monitor progress of TE differentiation. We conclude that, with the adoption of current improvement in the xylogenic Z. elegans culture, higher amounts of tracheary elements can be produced. This successful outcome raises the potential of the Zinnia system as a suitable model for cellulose and xylogenesis research.
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effects of water stress during growth of xylem anatomy xylem functioning and vase life in three Zinnia elegans cultivars
Acta Horticulturae, 2005Co-Authors: Peter Twumasi, W Van Ieperen, Ernst J Woltering, Anne Mie C Emons, J H N Schel, U Van Meeteren, D Van MarwijkAbstract:In cut flowers, hydraulic properties and dimensions of xylem vessels in the stem directly influence vase-life and thus post-harvest quality. Xylem hydraulic conductance as well as recovery from air embolisms at the start of vase life strongly depends on number, diameter and length of xylem vessels in the base of the cut flower stems. In this research we employed different water availability levels (high and low water content) in the growing medium of Zinnia elegans plants of three cultivars ('Envy', 'Purple Prince' and 'Scarlet Flame') to modify xylem anatomy and post-harvest xylem functioning and vase life of cut flowers from these plants. Vaselife was longer among fresh-cut Zinnia flowers in all three cultivars grown under low water content in the root medium. Zinnia flowers of all cultivars grown at high water content were not able to sufficiently restore water uptake at the start of their vase life. Shoot hydraulic conductivity was lower in water-stressed plants but it was not different among the three Zinnia cultivars within the same treatment. Anatomical analysis showed smaller xylem vessel diameters but no differences in xylem number and length, with the exception that in cultivar Purple Prince vessels were longer in well-watered plants. We conclude from these results that within these three Zinnia elegans cultivars water stress conditions in the root environment significantly affected xylem anatomy and functioning which correlates well with a longer vase life. Differences in xylem properties between the three cultivars due to pre-harvest watering treatments were limited.
