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Takayuki Hoson - One of the best experts on this subject based on the ideXlab platform.
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Effects of gravistimuli on osmoregulation in azuki bean Epicotyls
Advances in Space Research, 2013Co-Authors: Yan Zhang, Kazuyuki Wakabayashi, Kouichi Soga, Takayuki HosonAbstract:Abstract The effects of hypergravity on growth and osmoregulation were examined in dark-grown azuki bean Epicotyls. Elongation growth of Epicotyls was promptly suppressed by hypergravity at 300 g . On the contrary, the increase in fresh weight of Epicotyls during incubation was not suppressed by hypergravity at 300 g at least up to 6 h. Also, the level of total osmotic solutes increased during Epicotyl growth for 6 h, which was not affected by hypergravity. These results suggest that azuki bean Epicotyls are capable of maintaining osmoregulation even under 300 g conditions for a short period. On the other hand, the increase in fresh weight of Epicotyls was suppressed, in addition to suppression of elongation growth, when seedlings were treated with 300 g for 24 h. The increase in level of total osmotic solutes was also inhibited by 24 h hypergravity treatment, which was accounted by the reduced levels of organic solutes, such as sugars and amino acids. Furthermore, the dry weight of seeds decreased during incubation for 24 h, but the decrease was inhibited by hypergravity at 300 g . Hypergravity treatment at 300 g for 24 h also increased the pH value of apoplastic solution in Epicotyls. Taken together, these results suggest that the translocation of organic solutes from the seed to Epicotyls is inhibited by prolonged hypergravity treatment, which may underlie the suppression of Epicotyl growth, and that the breakdown of H + gradient across the plasma membrane in Epicotyl cells may be at least partly involved in the reduction of organic solute accumulation under hypergravity conditions.
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Cell wall-bound peroxidase activity and lignin formation in azuki bean Epicotyls grown under hypergravity conditions.
Journal of Plant Physiology, 2009Co-Authors: Kazuyuki Wakabayashi, Kouichi Soga, Saho Nakano, Takayuki HosonAbstract:Summary The effects of accelerated gravity stimuli on the cell wall-bound peroxidase activity and the lignin content were investigated along Epicotyls of azuki bean ( Vigna angularis ) seedlings. The endogenous growth occurred primarily in the upper regions of the Epicotyl, but no growth was detected in the middle or basal regions. Hypergravity treatment at 300 g for 6 h suppressed elongation growth and stimulated lateral expansion of the upper regions. The content of acetyl bromide-soluble lignin increased gradually from the apical to the basal regions of Epicotyls. Hypergravity treatment stimulated the increase in the lignin content in Epicotyls, particularly in the middle and basal regions. The peroxidase activity in the protein fraction extracted with a high ionic strength buffer from the cell wall preparation also increased gradually toward the basal region, and hypergravity treatment increased the activity in all Epicotyl regions. There was a close correlation between the lignin content and the enzyme activity. These results suggest that hypergravity increases the activity of cell wall-bound peroxidase followed by increases of the lignin formation in Epicotyl cell walls, which may contribute to increasing the rigidity of cell walls against the gravitational force.
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Role of xyloglucan in gravitropic bending of azuki bean Epicotyl.
Physiologia Plantarum, 2008Co-Authors: Toshimitsu Ikushima, Kouichi Soga, Takayuki Hoson, Teruo ShimmenAbstract:The mechanism of the gravitropic bending was studied in azuki bean Epicotyls. The cell wall extensibility of the lower side became higher than that of the upper side in the Epicotyl bending upward. The contents of matrix polysaccharides of the cell wall (pectin and xyloglucan in hemicellulose-II) in the lower side became smaller than those in the upper side. The molecular mass of xyloglucans in the lower side decreased. After an Epicotyl was fixed to a metal rod to prevent the bending, gravistimulation was applied. Fundamentally the same results were obtained with respect to rheological and chemical characteristics of the cell wall as those of Epicotyls showing gravitropic bending. The present results suggested that the initial gravitropic bending was caused by the increase in extensibility of the lower side and the decrease in extensibility of the upper side via the change of the cell wall matrix, especially xyloglucans.
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different cell wall polysaccharides are responsible for gravity resistance in the upper and the basal regions of azuki bean Epicotyls
Biological Sciences in Space, 2007Co-Authors: Saho Nakano, Kazuyuki Wakabayashi, Kouichi Soga, Takayuki HosonAbstract:Effects of hypergravity on growth and the levels of cell wall polysaccharides were examined along Epicotyls of dark-grown azuki bean (Vigna angularis Ohwi et Ohashi cv. Erimowase). Elongation growth occurred only in the upper regions, which was suppressed by hypergravity at 300 G. The fresh weight also increased in the upper regions, but hypergravity increased it only slightly in the basal regions. The thickness of Epicotyls was increased clearly in the upper regions and slightly in the basal regions by hypergravity. The levels of pectin, hemicellulose-I, and hemicellulose-II per unit length of Epicotyl were increased by hypergravity in the upper regions, but not in the basal ones. Also, the levels of xyloglucans were increased by hypergravity only in the upper regions. On the other hand, the levels of cellulose per unit length increased from the apical to the basal regions, and hypergravity further increased the levels in all regions. These results suggest that cellulose, instead of xyloglucans, acts as anti-gravitational polysaccharides in the basal regions. Cellulose and xyloglucans may cooperate in resistance of whole stem organs to the gravitational force.
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xyloglucan oligosaccharides cause cell wall loosening by enhancing xyloglucan endotransglucosylase hydrolase activity in azuki bean Epicotyls
Plant and Cell Physiology, 2004Co-Authors: Tomomi Kaku, Kazuyuki Wakabayashi, Akira Tabuchi, Takayuki HosonAbstract:;Addition of xyloglucan-derived oligosaccharides shifted the wall-bound xyloglucans to a lower molecular mass distribution and increased the cell wall extensibility of the native epidermal tissue strips isolated from azuki bean (Vigna angularis) Epicotyls. To ascertain the mechanism of oligosaccharide function, we examined the action of a xyloglucan endotransglucosylase/hydrolase (XTH) showing both endotransglucosylase and endohydrolase activities, isolated from azuki bean Epicotyl cell walls, in the presence of xyloglucan oligosaccharides. The addition of xyloglucan oligosaccharides enhanced the xyloglucan-degrading activity of XTH against isolated xyloglucan substrates. When the methanol-fixed epidermal tissue strips were incubated with XTH, the molecular mass of wall-bound xyloglucans was decreased and the cell wall extensibility increased markedly in the presence of the oligosaccharides. These results suggest that xyloglucan oligosaccharides stimulate the degradation of xyloglucans by enhancing the XTH activity within the cell wall architecture, thereby increasing the cell wall extensibility in azuki bean Epicotyls.
Béla Böddi - One of the best experts on this subject based on the ideXlab platform.
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delayed chlorophyll accumulation and pigment photodestruction in the Epicotyls of dark grown pea pisum sativum
Physiologia Plantarum, 2005Co-Authors: Béla Böddi, Roland Loudeche, Fabrice FranckAbstract:A comparison was performed of the tetrapyrrole transformations that occur upon irradiation of Epicotyl or leaves of dark-grown Pisum sativum L. (var. Zsuzsi, Hungary). High performance liquid chromatography analysis after continuous or flash-irradiation showed that the biosynthetic pathway from protochlorophyllide (Pchlide) to chlorophyll (Chl) a was markedly slowed down at the step of the reduction of geranylgeranyl(gg)-Chl to dihydrogeranylgeranyl (dhgg)-Chl in Epicotyls, whereas phytyl-Chl was synthesized in leaves subjected to the same light treatments. Quantitative pigment analysis during continuous irradiations of different intensities also showed that significant Pchlide photodestruction occurred in Epicotyls even under weak light. When both Pchlide and chlorophyllide and/or chlorophylls were present in Epicotyls, Pchlide photodestruction was faster under 630-nm light than under 670-nm light, which indicates that this process is most efficiently promoted by Pchlide excitation. Pre-incubation of Epicotyl segments with 10 mM ascorbate partly alleviated pigment photodestruction in white light. It is concluded that formation of photoactive Pchlide-Pchlide oxidoreductase complexes is important to prevent fast pigment photooxidation after Pchlide accumulation in the dark.
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Delayed chlorophyll accumulation and pigment photodestruction in the Epicotyls of dark‐grown pea (Pisum sativum)
Physiologia Plantarum, 2005Co-Authors: Béla Böddi, Roland Loudeche, Fabrice FranckAbstract:A comparison was performed of the tetrapyrrole transformations that occur upon irradiation of Epicotyl or leaves of dark-grown Pisum sativum L. (var. Zsuzsi, Hungary). High performance liquid chromatography analysis after continuous or flash-irradiation showed that the biosynthetic pathway from protochlorophyllide (Pchlide) to chlorophyll (Chl) a was markedly slowed down at the step of the reduction of geranylgeranyl(gg)-Chl to dihydrogeranylgeranyl (dhgg)-Chl in Epicotyls, whereas phytyl-Chl was synthesized in leaves subjected to the same light treatments. Quantitative pigment analysis during continuous irradiations of different intensities also showed that significant Pchlide photodestruction occurred in Epicotyls even under weak light. When both Pchlide and chlorophyllide and/or chlorophylls were present in Epicotyls, Pchlide photodestruction was faster under 630-nm light than under 670-nm light, which indicates that this process is most efficiently promoted by Pchlide excitation. Pre-incubation of Epicotyl segments with 10 mM ascorbate partly alleviated pigment photodestruction in white light. It is concluded that formation of photoactive Pchlide-Pchlide oxidoreductase complexes is important to prevent fast pigment photooxidation after Pchlide accumulation in the dark.
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Protochlorophyllide transformations and chlorophyll accumulation in Epicotyls of pea (Pisum sativum)
Physiologia Plantarum, 1996Co-Authors: Béla Böddi, Margareta Ryberg, Ivar Evertsson, Christer SundqvistAbstract:Low-temperature fluorescence emission spectra of Epicotyls of 6.5-day-old dark-grown seedlings of pea (Pisum sativum L.) showed the dominance of short-wavelength protoch lorophyllide forms with emission maxima at 629 and 636 nm, respectively. The presence of long-wavelength protochlorophyllide with emission maxima around 650 nm was just detectable. Accordingly, irradiation with millisecond flashes gave a minute formation of chlorophyllide. The chlorophyll(ide) formation varied along the Epicotyl. Irradiation with continuous light for 1.5 h resulted in an evident accumulation of chlorophyll(ide) in the upper part of the Epicotyl. Only small amounts accumulated in the middle section. The conversion of protochlorophyllide to chlorophyllide was temperature dependent and almost arrested at 0°C. The chlorophyll(ide) formed had one dominating fluorescence peak at 681 nm. Irradiation for 24 h gave almost 100 times more chlorophyll in the upper part of the Epicotyl than in the lower part. Electron micrographs from the upper part of the Epicotyl irradiated for 6 h showed plastids with several developing thylakoids, while the plastids in the lower part of the Epicotyl had only a few thylakoids. The dominance of short-wavelength protochlorophyllide forms indicated the presence of protochlorophyllide not bound to the active site of NADPH-protochlorophyllide oxidoreductase (EC 1.3.1.33). The inability of the short-wavelength form to transform into chlorophyllide with flash light denotes a dislocation from the active site. The time and temperature dependence of the chlorophyll(ide) formation in continuous light indicates that a relocation is required of the short-wavelength protochlorophyllide before chlorophyllide formation can occur.
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protochlorophyllide forms in non greening Epicotyls of dark grown pea pisum sativum
Physiologia Plantarum, 1994Co-Authors: Béla Böddi, Birgitta Mcewen, Margareta Ryberg, Christer SundqvistAbstract:Low-temperature fluorescence emission spectra of 6.5-day-old dark-grown Epicotyls of pea (Pisum sativum) revealed the presence of protochlorophyll(ide). The upper part of the Epicotyl contained 30% of the protochlorophyll(ide) content per fresh weight found in pea leaves, whereas the lower part contained 3%. Three discrete spectral forms of protochlorophyll(ide) were clearly distinguished after Gaussian deconvolution of fluorescence excitation and emission spectra. Adding the satellite bands of the Qy(0-0) transitions (the emission vibrational (Emv) bands with correlated amplitudes, gave the following delineation: Ex439–Em629–Emv684, Ex447–Em636–Emv700 and Ex456–Em650–Emv728. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunodetection of whole tissue extracts of the Epicotyl indicated the presence of NADPH-protochlorophyllide oxidoreductase (EC 1.3.1.33). Electron micrographs showed prolamellar bodies in at most 11 % of the plastid profiles of the Epicotyl cells. These prolamellar bodies were smaller, and many of them showed less regular structure than those of the leaves. Taken together, the results indicate that the protochlorophyll(ide) in Epicotyls is arranged in a different way than in leaves.
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Protochlorophyllide forms in non‐greening Epicotyls of dark‐grown pea (Pisum sativum)
Physiologia Plantarum, 1994Co-Authors: Béla Böddi, Birgitta Mcewen, Margareta Ryberg, Christer SundqvistAbstract:Low-temperature fluorescence emission spectra of 6.5-day-old dark-grown Epicotyls of pea (Pisum sativum) revealed the presence of protochlorophyll(ide). The upper part of the Epicotyl contained 30% of the protochlorophyll(ide) content per fresh weight found in pea leaves, whereas the lower part contained 3%. Three discrete spectral forms of protochlorophyll(ide) were clearly distinguished after Gaussian deconvolution of fluorescence excitation and emission spectra. Adding the satellite bands of the Qy(0-0) transitions (the emission vibrational (Emv) bands with correlated amplitudes, gave the following delineation: Ex439–Em629–Emv684, Ex447–Em636–Emv700 and Ex456–Em650–Emv728. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunodetection of whole tissue extracts of the Epicotyl indicated the presence of NADPH-protochlorophyllide oxidoreductase (EC 1.3.1.33). Electron micrographs showed prolamellar bodies in at most 11 % of the plastid profiles of the Epicotyl cells. These prolamellar bodies were smaller, and many of them showed less regular structure than those of the leaves. Taken together, the results indicate that the protochlorophyll(ide) in Epicotyls is arranged in a different way than in leaves.
Junichi Ueda - One of the best experts on this subject based on the ideXlab platform.
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Regulation of asymmetric polar auxin transport by PsPIN1 in endodermal tissues of etiolated Pisum sativum Epicotyls: focus on immunohistochemical analyses
Journal of Plant Research, 2018Co-Authors: Motoshi Kamada, Kensuke Miyamoto, Junichi Ueda, Akira HigashibataAbstract:This manuscript reports the production of specific polyclonal antibodies for PsPIN1, a putative auxin efflux carrier in Alaska pea ( Pisum sativum L.) plants, and the cellular immunolocalization of PsPIN1. When pea seeds were set with the seed axis horizontal to the upper surface of a rockwool block, and allowed to germinate and grow for 3 days in the dark, the Epicotyl grew upward. On the other hand, the application of 2,3,5-triiodobenzoic acid (TIBA) inhibited graviresponse. In the subapical Epicotyl regions, PsPIN1 has been found to localize in the basal side of the plasma membrane of cells in endodermal tissues. Asymmetric PsPIN1 localization between the proximal and distal sides of the Epicotyl was observed, the total amounts of PsPIN1 being more abundant in the proximal side. The asymmetric PsPIN1 distribution between the proximal and distal sides of the Epicotyl was well correlated with unequal polar auxin transport as well as asymmetric accumulation of mRNA of PsPIN1 (Ueda et al. in Biol Sci Space 26:32–41, 2012; Ueda et al. in Plant Biol 16(suppl 1):43–49, 2014). In the proximal side of an apical hook, PsPIN1 localized in the basal side of the plasma membrane of cells in endodermal tissues, whereas in the distal side, the abundant distribution of PsPIN1 localized in the basal-lower (endodermal) side of the basal plasma membrane, suggesting possible lateral auxin movement from the distal side to the proximal side in this region. The application of TIBA significantly reduced the amount of PsPIN1 in the proximal side of Epicotyls, but little in the distal side. These results suggest that unequal auxin transport in Epicotyls during the early growth stage of etiolated pea seedlings is derived from asymmetric PsPIN1 localization in the apical hook and subapical region of Epicotyls, and that asymmetric transport between the proximal and distal sides of Epicotyls is required for the graviresponse of Epicotyls.
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a gravitropic stimulation induced growth inhibitor β isoxazolin 5 on 2yl alanine is a possible mediator of negative gravitropic bending of Epicotyls in etiolated pisum sativum seedlings
Plant Growth Regulation, 2017Co-Authors: Tsuyoshi Hasegawa, Hideyuki Shigemori, Koji Hasegawa, Junichi Ueda, Yume Omiya, Mayumi Koide, Kensuke MiyamotoAbstract:Negative gravitropic bending and its possible mediator in etiolated Alaska pea seedlings were intensively studied in comparison with seedlings of an agravitropic mutant, ageotropum. When 3.5-day-old etiolated Alaska seedlings were horizontally placed, the growth suppression at the upper side of the Epicotyls began 10 min after the onset of the gravitropic stimulation, whereas the growth acceleration at the lower side began at 30 min, resulting in negative gravitropic bending. In contrast, no gravitropic bending was observed in the etiolated ageotropum seedlings, for which the Epicotyls show an automorphogenesis-like growth. Strenuous efforts to identify a possible mediator that induces the gravitropic bending resulted in successfully identifying β-(isoxazolin-5-on-2yl)-alanine (βIA). The unilateral application of βIA to the etiolated Alaska Epicotyls substantially induced Epicotyl bending toward the application site, indicating that βIA could act as a growth inhibitor. Analyses of the distribution of βIA in the upper and lower flanks of the etiolated Alaska Epicotyls revealed that its content rapidly increased twice in the upper flanks compared with that in the lower ones in response to gravitropic stimulation, whereas its content in the lower flanks was almost equal to that in the vertical control. In etiolated ageotropum Epicotyls, an almost equal amount of βIA was distributed in the upper and lower flanks of Epicotyls. These results suggest that a gravitropic stimulation increases βIA in the upper flank, resulting in the negative gravitropic bending of Epicotyls via the suppression of the growth rate at the upper side of Epicotyls in the etiolated Alaska pea seedlings.
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gravity controlled asymmetrical transport of auxin regulates a gravitropic response in the early growth stage of etiolated pea pisum sativum Epicotyls studies using simulated microgravity conditions on a three dimensional clinostat and using an agrav
Journal of Plant Research, 2007Co-Authors: Tomoki Hoshino, Kensuke Miyamoto, Junichi UedaAbstract:Increased expression of the auxin-inducible gene PsIAA4/5 was observed in the elongated side of Epicotyls in early growth stages of etiolated pea (Pisum sativum L. cv. Alaska) seedlings grown in a horizontal or an inclined position under 1 g conditions. Under simulated microgravity conditions on a 3D clinostat, accumulation of PsIAA4/5 mRNA was found throughout Epicotyls showing automorphosis. Polar auxin transport in the proximal side of Epicotyls changed when the seedlings were grown in a horizontal or an inclined position under 1 g conditions, but that under clinorotation did not, regardless of the direction of seed setting. Accumulation of PsPIN1 and PsPIN2 mRNAs in Epicotyls was affected by gravistimulation, but not by clinorotation. Under 1 g conditions, auxin-transport inhibitors made Epicotyls of seedlings grown in a horizontal or inclined position grow toward the proximal direction to cotyledons. These inhibitors led to Epicotyl bending toward the cotyledons in seedlings grown in an inclined position under clinorotation. Polar auxin transport, as well as growth direction, of Epicotyls of the agravitropic mutant ageotropum did not respond to various gravistimulation. These results suggest that alteration of polar auxin transport in the proximal side of Epicotyls regulates the graviresponse of pea Epicotyls.
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Auxin polar transport of etiolated Ageotropum pea Epicotyls is not affected by gravistimulation: Relevance to automorphosis-like growth and development
Advances in Space Research, 2007Co-Authors: Kensuke Miyamoto, Tomoki Hoshino, Yoshinori Takahashi, Junichi UedaAbstract:Abstract There appears to be a close relationship between automorphosis and changes in auxin polar transport due to the fact that microgravity conditions cause both changes in the activity of auxin polar transport and in automorphosis of etiolated Alaska pea Epicotyls. In addition, the application of inhibitors of auxin polar transport results in automorphosis-like growth and development. To elucidate the role of auxin polar transport in gravimorphogenesis in etiolated pea seedlings, we have studied the effects of gravistimulation on growth and development, and auxin polar transport in Epicotyls of an agravitropic pea mutant “ Ageotropum ” seedlings and the normal “Alaska” seedlings. When the embryo axes in seeds of Alaska pea were set in a vertical (parallel to the direction of gravity) or a horizontal (vertical to the direction of gravity) position, and allowed to germinate and grow under 1 g conditions in the dark for 3 or 6.5 days, the Epicotyls grew upward due to negative gravitropic responses regardless of gravistimulation during seed germination. On the other hand, Epicotyls of etiolated Ageotropum pea seedlings showed automorphosis-like bending away from the cotyledons regardless of gravistimulation during seed germination. Automorphosis-like Epicotyl bending of etiolated Ageotropum pea seedlings was also unaffected by clinorotation on a three-dimensional (3-D) clinostat. The activity of auxin polar transport in the 2nd internodes of 6.5-d-old etiolated Ageotropum pea seedlings was lower than those of Alaska pea seedlings, and was not affected by clinorotation on a 3-D clinostat or by changes in gravity conditions during seed germination. These findings strongly support our previous studies that showed that normal auxin polar transport is required for the normal graviresponse of Epicotyls in etiolated pea seedlings.
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Requirement for the gravity-controlled transport of auxin for a negative gravitropic response of Epicotyls in the early growth stage of etiolated pea seedlings.
Plant and Cell Physiology, 2006Co-Authors: Tomoki Hoshino, Kensuke Miyamoto, Junichi UedaAbstract:Gravity-controlled transport of auxin was studied for a negative gravitropic response in the early growth stage of etiolated pea (Pisum sativum L. cv. Alaska) seedlings, in which Epicotyl bending was observed near the cotyledon nodes of the seedlings grown continuously from seeds germinated in a horizontal or an inclined position. Increased expression of an auxin-inducible gene, PsIAA4/5, was observed in the elongated side of Epicotyls grown in a horizontal or an inclined position. Regardless of the conditions of seed germination, polar auxin transport in the proximal side of the first internodes of the seedlings was significantly higher than in the distal side. Polar auxin transport in the proximal side of Epicotyls grown in an inclined position was significantly lower than in those grown in a horizontal position. In contrast, lateral auxin distribution from the proximal to distal sides in Epicotyls grown in an inclined position was significantly higher than in Epicotyls grown in a horizontal position. Accumulation of PsPIN1 mRNA encoding a putative auxin efflux facilitator, which was observed in vascular tissue, cortex and epidermis in the proximal and distal sides of Epicotyls, was markedly influenced by gravistimulation. These results strongly suggest that gravistimulation induces changeable polar auxin transport and one-way lateral auxin distribution in Epicotyls as well as asymmetric auxin accumulation in the proximal and distal sides of Epicotyls, resulting in a negative gravitropic response of Epicotyls in the early growth stage of pea seedlings.
Christer Sundqvist - One of the best experts on this subject based on the ideXlab platform.
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Protochlorophyllide transformations and chlorophyll accumulation in Epicotyls of pea (Pisum sativum)
Physiologia Plantarum, 1996Co-Authors: Béla Böddi, Margareta Ryberg, Ivar Evertsson, Christer SundqvistAbstract:Low-temperature fluorescence emission spectra of Epicotyls of 6.5-day-old dark-grown seedlings of pea (Pisum sativum L.) showed the dominance of short-wavelength protoch lorophyllide forms with emission maxima at 629 and 636 nm, respectively. The presence of long-wavelength protochlorophyllide with emission maxima around 650 nm was just detectable. Accordingly, irradiation with millisecond flashes gave a minute formation of chlorophyllide. The chlorophyll(ide) formation varied along the Epicotyl. Irradiation with continuous light for 1.5 h resulted in an evident accumulation of chlorophyll(ide) in the upper part of the Epicotyl. Only small amounts accumulated in the middle section. The conversion of protochlorophyllide to chlorophyllide was temperature dependent and almost arrested at 0°C. The chlorophyll(ide) formed had one dominating fluorescence peak at 681 nm. Irradiation for 24 h gave almost 100 times more chlorophyll in the upper part of the Epicotyl than in the lower part. Electron micrographs from the upper part of the Epicotyl irradiated for 6 h showed plastids with several developing thylakoids, while the plastids in the lower part of the Epicotyl had only a few thylakoids. The dominance of short-wavelength protochlorophyllide forms indicated the presence of protochlorophyllide not bound to the active site of NADPH-protochlorophyllide oxidoreductase (EC 1.3.1.33). The inability of the short-wavelength form to transform into chlorophyllide with flash light denotes a dislocation from the active site. The time and temperature dependence of the chlorophyll(ide) formation in continuous light indicates that a relocation is required of the short-wavelength protochlorophyllide before chlorophyllide formation can occur.
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protochlorophyllide forms in non greening Epicotyls of dark grown pea pisum sativum
Physiologia Plantarum, 1994Co-Authors: Béla Böddi, Birgitta Mcewen, Margareta Ryberg, Christer SundqvistAbstract:Low-temperature fluorescence emission spectra of 6.5-day-old dark-grown Epicotyls of pea (Pisum sativum) revealed the presence of protochlorophyll(ide). The upper part of the Epicotyl contained 30% of the protochlorophyll(ide) content per fresh weight found in pea leaves, whereas the lower part contained 3%. Three discrete spectral forms of protochlorophyll(ide) were clearly distinguished after Gaussian deconvolution of fluorescence excitation and emission spectra. Adding the satellite bands of the Qy(0-0) transitions (the emission vibrational (Emv) bands with correlated amplitudes, gave the following delineation: Ex439–Em629–Emv684, Ex447–Em636–Emv700 and Ex456–Em650–Emv728. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunodetection of whole tissue extracts of the Epicotyl indicated the presence of NADPH-protochlorophyllide oxidoreductase (EC 1.3.1.33). Electron micrographs showed prolamellar bodies in at most 11 % of the plastid profiles of the Epicotyl cells. These prolamellar bodies were smaller, and many of them showed less regular structure than those of the leaves. Taken together, the results indicate that the protochlorophyll(ide) in Epicotyls is arranged in a different way than in leaves.
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Protochlorophyllide forms in non‐greening Epicotyls of dark‐grown pea (Pisum sativum)
Physiologia Plantarum, 1994Co-Authors: Béla Böddi, Birgitta Mcewen, Margareta Ryberg, Christer SundqvistAbstract:Low-temperature fluorescence emission spectra of 6.5-day-old dark-grown Epicotyls of pea (Pisum sativum) revealed the presence of protochlorophyll(ide). The upper part of the Epicotyl contained 30% of the protochlorophyll(ide) content per fresh weight found in pea leaves, whereas the lower part contained 3%. Three discrete spectral forms of protochlorophyll(ide) were clearly distinguished after Gaussian deconvolution of fluorescence excitation and emission spectra. Adding the satellite bands of the Qy(0-0) transitions (the emission vibrational (Emv) bands with correlated amplitudes, gave the following delineation: Ex439–Em629–Emv684, Ex447–Em636–Emv700 and Ex456–Em650–Emv728. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunodetection of whole tissue extracts of the Epicotyl indicated the presence of NADPH-protochlorophyllide oxidoreductase (EC 1.3.1.33). Electron micrographs showed prolamellar bodies in at most 11 % of the plastid profiles of the Epicotyl cells. These prolamellar bodies were smaller, and many of them showed less regular structure than those of the leaves. Taken together, the results indicate that the protochlorophyll(ide) in Epicotyls is arranged in a different way than in leaves.
Kensuke Miyamoto - One of the best experts on this subject based on the ideXlab platform.
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Gravity-regulated localization of PsPIN1 is important for polar auxin transport in etiolated pea seedlings: Relevance to the International Space Station experiment.
Life Sciences in Space Research, 2019Co-Authors: Motoshi Kamada, Kensuke Miyamoto, Eiji Uheda, Mariko Oka, Chiaki Yamazaki, Toru Shimazu, Hiromi Sano, Riko Inoue, Yayoi Fujitaka, Haruo KasaharaAbstract:Abstract To clarify the mechanism of gravity-controlled polar auxin transport, we conducted the International Space Station (ISS) experiment “Auxin Transport” (identified by NASA's operation nomenclature) in 2016 and 2017, focusing on the expression of genes related to auxin efflux carrier protein PsPIN1 and its localization in the hook and Epicotyl cells of etiolated Alaska pea seedlings grown for three days in the dark under microgravity (μ g ) and artificial 1 g conditions on a centrifuge in the Cell Biology Experimental Facility (CBEF) in the ISS, and under 1 g conditions on Earth. Regardless of gravity conditions, the accumulation of PsPIN1 mRNA in the proximal side of Epicotyls of the seedlings was not different, but tended to be slightly higher as compared with that in the distal side. 2,3,5-Triiodobenzoic acid (TIBA) also did not affect the accumulation of PsPIN1 mRNA in the proximal and distal sides of Epicotyls. However, in the apical hook region, TIBA increased the accumulation of PsPIN1 mRNA under μ g conditions as compared with that under artificial 1 g conditions in the ISS. The accumulation of PsPIN1 proteins in Epicotyls determined by western blotting was almost parallel to that of mRNA of PsPIN1 . Immunohistochemical analysis with a specific polyclonal antibody of PsPIN1 revealed that a majority of PsPIN1 in the apical hook and subapical regions of the seedlings grown under artificial 1 g conditions in the ISS localized in the basal side (rootward) of the plasma membrane of the endodermal tissues. Conversely, in the seedlings grown under μ g conditions, localization of PsPIN1 was greatly disarrayed. TIBA substantially altered the cellular localization pattern of PsPIN1, especially under μ g conditions. These results strongly suggest that the mechanisms by which gravity controls polar auxin transport are more likely to be due to the membrane localization of PsPIN1. This physiologically valuable report describes a close relationship between gravity-controlled polar auxin transport and the localization of auxin efflux carrier PsPIN1 in etiolated pea seedlings based on the μ g experiment conducted in space.
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Regulation of asymmetric polar auxin transport by PsPIN1 in endodermal tissues of etiolated Pisum sativum Epicotyls: focus on immunohistochemical analyses
Journal of Plant Research, 2018Co-Authors: Motoshi Kamada, Kensuke Miyamoto, Junichi Ueda, Akira HigashibataAbstract:This manuscript reports the production of specific polyclonal antibodies for PsPIN1, a putative auxin efflux carrier in Alaska pea ( Pisum sativum L.) plants, and the cellular immunolocalization of PsPIN1. When pea seeds were set with the seed axis horizontal to the upper surface of a rockwool block, and allowed to germinate and grow for 3 days in the dark, the Epicotyl grew upward. On the other hand, the application of 2,3,5-triiodobenzoic acid (TIBA) inhibited graviresponse. In the subapical Epicotyl regions, PsPIN1 has been found to localize in the basal side of the plasma membrane of cells in endodermal tissues. Asymmetric PsPIN1 localization between the proximal and distal sides of the Epicotyl was observed, the total amounts of PsPIN1 being more abundant in the proximal side. The asymmetric PsPIN1 distribution between the proximal and distal sides of the Epicotyl was well correlated with unequal polar auxin transport as well as asymmetric accumulation of mRNA of PsPIN1 (Ueda et al. in Biol Sci Space 26:32–41, 2012; Ueda et al. in Plant Biol 16(suppl 1):43–49, 2014). In the proximal side of an apical hook, PsPIN1 localized in the basal side of the plasma membrane of cells in endodermal tissues, whereas in the distal side, the abundant distribution of PsPIN1 localized in the basal-lower (endodermal) side of the basal plasma membrane, suggesting possible lateral auxin movement from the distal side to the proximal side in this region. The application of TIBA significantly reduced the amount of PsPIN1 in the proximal side of Epicotyls, but little in the distal side. These results suggest that unequal auxin transport in Epicotyls during the early growth stage of etiolated pea seedlings is derived from asymmetric PsPIN1 localization in the apical hook and subapical region of Epicotyls, and that asymmetric transport between the proximal and distal sides of Epicotyls is required for the graviresponse of Epicotyls.
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a gravitropic stimulation induced growth inhibitor β isoxazolin 5 on 2yl alanine is a possible mediator of negative gravitropic bending of Epicotyls in etiolated pisum sativum seedlings
Plant Growth Regulation, 2017Co-Authors: Tsuyoshi Hasegawa, Hideyuki Shigemori, Koji Hasegawa, Junichi Ueda, Yume Omiya, Mayumi Koide, Kensuke MiyamotoAbstract:Negative gravitropic bending and its possible mediator in etiolated Alaska pea seedlings were intensively studied in comparison with seedlings of an agravitropic mutant, ageotropum. When 3.5-day-old etiolated Alaska seedlings were horizontally placed, the growth suppression at the upper side of the Epicotyls began 10 min after the onset of the gravitropic stimulation, whereas the growth acceleration at the lower side began at 30 min, resulting in negative gravitropic bending. In contrast, no gravitropic bending was observed in the etiolated ageotropum seedlings, for which the Epicotyls show an automorphogenesis-like growth. Strenuous efforts to identify a possible mediator that induces the gravitropic bending resulted in successfully identifying β-(isoxazolin-5-on-2yl)-alanine (βIA). The unilateral application of βIA to the etiolated Alaska Epicotyls substantially induced Epicotyl bending toward the application site, indicating that βIA could act as a growth inhibitor. Analyses of the distribution of βIA in the upper and lower flanks of the etiolated Alaska Epicotyls revealed that its content rapidly increased twice in the upper flanks compared with that in the lower ones in response to gravitropic stimulation, whereas its content in the lower flanks was almost equal to that in the vertical control. In etiolated ageotropum Epicotyls, an almost equal amount of βIA was distributed in the upper and lower flanks of Epicotyls. These results suggest that a gravitropic stimulation increases βIA in the upper flank, resulting in the negative gravitropic bending of Epicotyls via the suppression of the growth rate at the upper side of Epicotyls in the etiolated Alaska pea seedlings.
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gravity controlled asymmetrical transport of auxin regulates a gravitropic response in the early growth stage of etiolated pea pisum sativum Epicotyls studies using simulated microgravity conditions on a three dimensional clinostat and using an agrav
Journal of Plant Research, 2007Co-Authors: Tomoki Hoshino, Kensuke Miyamoto, Junichi UedaAbstract:Increased expression of the auxin-inducible gene PsIAA4/5 was observed in the elongated side of Epicotyls in early growth stages of etiolated pea (Pisum sativum L. cv. Alaska) seedlings grown in a horizontal or an inclined position under 1 g conditions. Under simulated microgravity conditions on a 3D clinostat, accumulation of PsIAA4/5 mRNA was found throughout Epicotyls showing automorphosis. Polar auxin transport in the proximal side of Epicotyls changed when the seedlings were grown in a horizontal or an inclined position under 1 g conditions, but that under clinorotation did not, regardless of the direction of seed setting. Accumulation of PsPIN1 and PsPIN2 mRNAs in Epicotyls was affected by gravistimulation, but not by clinorotation. Under 1 g conditions, auxin-transport inhibitors made Epicotyls of seedlings grown in a horizontal or inclined position grow toward the proximal direction to cotyledons. These inhibitors led to Epicotyl bending toward the cotyledons in seedlings grown in an inclined position under clinorotation. Polar auxin transport, as well as growth direction, of Epicotyls of the agravitropic mutant ageotropum did not respond to various gravistimulation. These results suggest that alteration of polar auxin transport in the proximal side of Epicotyls regulates the graviresponse of pea Epicotyls.
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Auxin polar transport of etiolated Ageotropum pea Epicotyls is not affected by gravistimulation: Relevance to automorphosis-like growth and development
Advances in Space Research, 2007Co-Authors: Kensuke Miyamoto, Tomoki Hoshino, Yoshinori Takahashi, Junichi UedaAbstract:Abstract There appears to be a close relationship between automorphosis and changes in auxin polar transport due to the fact that microgravity conditions cause both changes in the activity of auxin polar transport and in automorphosis of etiolated Alaska pea Epicotyls. In addition, the application of inhibitors of auxin polar transport results in automorphosis-like growth and development. To elucidate the role of auxin polar transport in gravimorphogenesis in etiolated pea seedlings, we have studied the effects of gravistimulation on growth and development, and auxin polar transport in Epicotyls of an agravitropic pea mutant “ Ageotropum ” seedlings and the normal “Alaska” seedlings. When the embryo axes in seeds of Alaska pea were set in a vertical (parallel to the direction of gravity) or a horizontal (vertical to the direction of gravity) position, and allowed to germinate and grow under 1 g conditions in the dark for 3 or 6.5 days, the Epicotyls grew upward due to negative gravitropic responses regardless of gravistimulation during seed germination. On the other hand, Epicotyls of etiolated Ageotropum pea seedlings showed automorphosis-like bending away from the cotyledons regardless of gravistimulation during seed germination. Automorphosis-like Epicotyl bending of etiolated Ageotropum pea seedlings was also unaffected by clinorotation on a three-dimensional (3-D) clinostat. The activity of auxin polar transport in the 2nd internodes of 6.5-d-old etiolated Ageotropum pea seedlings was lower than those of Alaska pea seedlings, and was not affected by clinorotation on a 3-D clinostat or by changes in gravity conditions during seed germination. These findings strongly support our previous studies that showed that normal auxin polar transport is required for the normal graviresponse of Epicotyls in etiolated pea seedlings.