The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform

Toshitsugu Nakano - One of the best experts on this subject based on the ideXlab platform.

  • development and regulation of Pedicel abscission in tomato
    Frontiers in Plant Science, 2015
    Co-Authors: Toshitsugu Nakano
    Abstract:

    To shed unfertilized flowers or ripe fruits, many plant species develop a Pedicel abscission zone (AZ), a specialized tissue that develops between the organ and the main body of the plant. Regulation of Pedicel abscission is an important agricultural concern because pre-harvest abscission can reduce yields of fruit or grain crops, such as apples, rice, wheat, etc. Tomato has been studied as a model system for abscission, as tomato plants develop a distinct AZ at the midpoint of the Pedicel and several tomato mutants, such as jointless, have Pedicels that lack an AZ. This mini-review focuses on recent advances in research on the mechanisms regulating tomato Pedicel abscission. Molecular genetic studies revealed that three MADS-box transcription factors interactively play a central role in Pedicel AZ development. Transcriptome analyses identified activities involved in abscission and also found novel transcription factors that may regulate AZ activities. Another study identified transcription factors mediating abscission pathways from induction signals to activation of cell wall hydrolysis. These recent findings in tomato will enable significant advances in understanding the regulation of abscission in other key agronomic species.

  • apple svp family mads box proteins and the tomato Pedicel abscission zone regulator jointless have similar molecular activities
    Plant and Cell Physiology, 2015
    Co-Authors: Toshitsugu Nakano, Hiroki Kato, Yoko Shima
    Abstract:

    : Pedicel abscission occurs widely in fruit-bearing plants to detach ripe, senescent or diseased organs, and regulation of abscission plays a substantial role in regulating yield and quality in fruit crops. In tomato, development of Pedicel abscission zones (AZs) requires the MADS-box genes JOINTLESS (J), MACROCALYX (MC) and SlMBP21. In other plants, however, the involvement of MADS-box genes in Pedicel abscission remains unclear. Here, we used genetic and biochemical methods to characterize apple J homologs in the context of the regulation of abscission in tomato. We identified three genes encoding two J homologs, MdJa and MdJb. Similarly to J, MdJa and MdJb interacted with MC and SlMBP21, but their interactions differed slightly: like J, MdJb formed a multimer (probably a tetramer) with SlMBP21; however, MdJa formed multimers to a lesser extent. Ectopic expression of MdJb in a J-deficient tomato mutant restored development of functional Pedicel AZs, but ectopic expression of MdJa did not complement j mutants. Introduction of MdJb also restored expression of J-dependent genes in the mutant, such as genes for polygalacturonase, cellulase and AZ-specific transcription factors. These results suggest a potentially conserved mechanism of Pedicel AZ development in apple and other plants, regulated by MADS-box transcription factors.

  • the ap2 erf transcription factor slerf52 functions in flower Pedicel abscission in tomato
    Journal of Experimental Botany, 2014
    Co-Authors: Toshitsugu Nakano, Masaki Fujisawa, Yoko Shima
    Abstract:

    In plants, abscission removes senescent, injured, infected, or dispensable organs. Induced by auxin depletion and an ethylene burst, abscission requires pronounced changes in gene expression, including genes for cell separation enzymes and regulators of signal transduction and transcription. However, the understanding of the molecular basis of this regulation remains incomplete. To examine gene regulation in abscission, this study examined an ERF family transcription factor, tomato (Solanum lycopersicum) ETHYLENE-RESPONSIVE FACTOR 52 (SlERF52). SlERF52 is specifically expressed in Pedicel abscission zones (AZs) and SlERF52 expression is suppressed in plants with impaired function of MACROCALYX and JOINTLESS, which regulate Pedicel AZ development. RNA interference was used to knock down SlERF52 expression to show that SlERF52 functions in flower Pedicel abscission. When treated with an abscission-inducing stimulus, the SlERF52-suppressed plants showed a significant delay in flower abscission compared with wild type. They also showed reduced upregulation of the genes for the abscission-associated enzymes cellulase and polygalacturonase. SlERF52 suppression also affected gene expression before the abscission stimulus, inhibiting the expression of Pedicel AZ-specific transcription factor genes, such as the tomato WUSCHEL homologue, GOBLET, and Lateral suppressor, which may regulate meristematic activities in Pedicel AZs. These results suggest that SlERF52 plays a pivotal role in transcriptional regulation in Pedicel AZs at both pre-abscission and abscission stages.

  • The AP2/ERF transcription factor SlERF52 functions in flower Pedicel abscission in tomato
    Journal of Experimental Botany, 2014
    Co-Authors: Toshitsugu Nakano, Masaki Fujisawa, Yoko Shima
    Abstract:

    In plants, abscission removes senescent, injured, infected, or dispensable organs. Induced by auxin depletion and an ethylene burst, abscission requires pronounced changes in gene expression, including genes for cell separation enzymes and regulators of signal transduction and transcription. However, the understanding of the molecular basis of this regulation remains incomplete. To examine gene regulation in abscission, this study examined an ERF family transcription factor, tomato (Solanum lycopersicum) ETHYLENE-RESPONSIVE FACTOR 52 (SlERF52). SlERF52 is specifically expressed in Pedicel abscission zones (AZs) and SlERF52 expression is suppressed in plants with impaired function of MACROCALYX and JOINTLESS, which regulate Pedicel AZ development. RNA interference was used to knock down SlERF52 expression to show that SlERF52 functions in flower Pedicel abscission. When treated with an abscission-inducing stimulus, the SlERF52-suppressed plants showed a significant delay in flower abscission compared with wild type. They also showed reduced upregulation of the genes for the abscission-associated enzymes cellulase and polygalacturonase. SlERF52 suppression also affected gene expression before the abscission stimulus, inhibiting the expression of Pedicel AZ-specific transcription factor genes, such as the tomato WUSCHEL homologue, GOBLET, and Lateral suppressor, which may regulate meristematic activities in Pedicel AZs. These results suggest that SlERF52 plays a pivotal role in transcriptional regulation in Pedicel AZs at both pre-abscission and abscission stages.

Steven Jansen - One of the best experts on this subject based on the ideXlab platform.

  • The application of various anatomical techniques for studying the hydraulic network in tomato fruit Pedicels
    Protoplasma, 2010
    Co-Authors: Dragana Rančić, Sofija Pekić Quarrie, Radenko Radošević, Maja Terzić, Ilinka Pećinar, Radmila Stikić, Steven Jansen
    Abstract:

    The abscission zone in fruit Pedicels plays an important role in affecting not only water uptake in the developing fruit, but also in the transport of chemical signals from root to shoot. In order to characterize the hydraulic network of tomato fruit Pedicels, we applied various techniques, including light, fluorescence microscopy, electron microscopy, maceration, tissue clearing, and X-ray computed tomography. Because of significant changes in xylem anatomy, the abscission zone in tomato fruit Pedicels is illustrated to show a clear reduction in hydraulic conductance. Based on anatomical measurements, the theoretical axial xylem conductance was calculated via the Hagen–Poiseuille law, suggesting that the hydraulic resistance of the abscission zone increases at least two orders of magnitude compared to the Pedicel zone near the stem. The advantages and shortcomings of the microscope techniques applied are discussed.

Yoko Shima - One of the best experts on this subject based on the ideXlab platform.

  • apple svp family mads box proteins and the tomato Pedicel abscission zone regulator jointless have similar molecular activities
    Plant and Cell Physiology, 2015
    Co-Authors: Toshitsugu Nakano, Hiroki Kato, Yoko Shima
    Abstract:

    : Pedicel abscission occurs widely in fruit-bearing plants to detach ripe, senescent or diseased organs, and regulation of abscission plays a substantial role in regulating yield and quality in fruit crops. In tomato, development of Pedicel abscission zones (AZs) requires the MADS-box genes JOINTLESS (J), MACROCALYX (MC) and SlMBP21. In other plants, however, the involvement of MADS-box genes in Pedicel abscission remains unclear. Here, we used genetic and biochemical methods to characterize apple J homologs in the context of the regulation of abscission in tomato. We identified three genes encoding two J homologs, MdJa and MdJb. Similarly to J, MdJa and MdJb interacted with MC and SlMBP21, but their interactions differed slightly: like J, MdJb formed a multimer (probably a tetramer) with SlMBP21; however, MdJa formed multimers to a lesser extent. Ectopic expression of MdJb in a J-deficient tomato mutant restored development of functional Pedicel AZs, but ectopic expression of MdJa did not complement j mutants. Introduction of MdJb also restored expression of J-dependent genes in the mutant, such as genes for polygalacturonase, cellulase and AZ-specific transcription factors. These results suggest a potentially conserved mechanism of Pedicel AZ development in apple and other plants, regulated by MADS-box transcription factors.

  • the ap2 erf transcription factor slerf52 functions in flower Pedicel abscission in tomato
    Journal of Experimental Botany, 2014
    Co-Authors: Toshitsugu Nakano, Masaki Fujisawa, Yoko Shima
    Abstract:

    In plants, abscission removes senescent, injured, infected, or dispensable organs. Induced by auxin depletion and an ethylene burst, abscission requires pronounced changes in gene expression, including genes for cell separation enzymes and regulators of signal transduction and transcription. However, the understanding of the molecular basis of this regulation remains incomplete. To examine gene regulation in abscission, this study examined an ERF family transcription factor, tomato (Solanum lycopersicum) ETHYLENE-RESPONSIVE FACTOR 52 (SlERF52). SlERF52 is specifically expressed in Pedicel abscission zones (AZs) and SlERF52 expression is suppressed in plants with impaired function of MACROCALYX and JOINTLESS, which regulate Pedicel AZ development. RNA interference was used to knock down SlERF52 expression to show that SlERF52 functions in flower Pedicel abscission. When treated with an abscission-inducing stimulus, the SlERF52-suppressed plants showed a significant delay in flower abscission compared with wild type. They also showed reduced upregulation of the genes for the abscission-associated enzymes cellulase and polygalacturonase. SlERF52 suppression also affected gene expression before the abscission stimulus, inhibiting the expression of Pedicel AZ-specific transcription factor genes, such as the tomato WUSCHEL homologue, GOBLET, and Lateral suppressor, which may regulate meristematic activities in Pedicel AZs. These results suggest that SlERF52 plays a pivotal role in transcriptional regulation in Pedicel AZs at both pre-abscission and abscission stages.

  • The AP2/ERF transcription factor SlERF52 functions in flower Pedicel abscission in tomato
    Journal of Experimental Botany, 2014
    Co-Authors: Toshitsugu Nakano, Masaki Fujisawa, Yoko Shima
    Abstract:

    In plants, abscission removes senescent, injured, infected, or dispensable organs. Induced by auxin depletion and an ethylene burst, abscission requires pronounced changes in gene expression, including genes for cell separation enzymes and regulators of signal transduction and transcription. However, the understanding of the molecular basis of this regulation remains incomplete. To examine gene regulation in abscission, this study examined an ERF family transcription factor, tomato (Solanum lycopersicum) ETHYLENE-RESPONSIVE FACTOR 52 (SlERF52). SlERF52 is specifically expressed in Pedicel abscission zones (AZs) and SlERF52 expression is suppressed in plants with impaired function of MACROCALYX and JOINTLESS, which regulate Pedicel AZ development. RNA interference was used to knock down SlERF52 expression to show that SlERF52 functions in flower Pedicel abscission. When treated with an abscission-inducing stimulus, the SlERF52-suppressed plants showed a significant delay in flower abscission compared with wild type. They also showed reduced upregulation of the genes for the abscission-associated enzymes cellulase and polygalacturonase. SlERF52 suppression also affected gene expression before the abscission stimulus, inhibiting the expression of Pedicel AZ-specific transcription factor genes, such as the tomato WUSCHEL homologue, GOBLET, and Lateral suppressor, which may regulate meristematic activities in Pedicel AZs. These results suggest that SlERF52 plays a pivotal role in transcriptional regulation in Pedicel AZs at both pre-abscission and abscission stages.

Erin E Irish - One of the best experts on this subject based on the ideXlab platform.

  • JOINTLESS suppresses sympodial identity in inflorescence meristems of tomato
    Planta, 2006
    Co-Authors: Eugene J Szymkowiak, Erin E Irish
    Abstract:

    Unlike monopodial plants, in which flowering terminates growth of a shoot, plants exhibiting sympodial shoot architecture maintain the potential for indeterminate growth even after converting to floral development. This vegetative indeterminacy is conferred by a special type of axillary meristem, the sympodial meristem, which exhibits precocious but determinate growth. The reiterative formation of sympodial meristems as the plant grows results in a shoot composed of a series of modules, each consisting of a limited number of vegetative nodes and terminated by a flower or inflorescence. To determine how sympodial meristems differ from other shoot meristems, we examined interactions between mutations that affect various shoot meristem types in tomato ( Lycopersicon esculentum Mill.). Analysis of double mutant combinations of jointless, lateral suppressor , self-pruning, blind , and anantha showed that sympodial meristems share regulatory features with inflorescence meristems. Genetic studies on the jointless mutation implicated this gene in suppressing sympodial meristem fate in the inflorescence. As this mutation has a second phenotype, the elimination of the Pedicel abscission zone, we examined the expression pattern of JOINTLESS to test whether Pedicel development is involved in directing shoot architecture. We found that this MADS box gene is expressed in a variety of shoot meristems, including inflorescence, floral, sympodial, and axillary meristems, as well as in early staged floral organs, in sporogenous tissues of anthers, and in ovules. Lack of expression in developing Pedicels indicates abscission zone development does not rely on JOINTLESS transcription in the differentiating cells. We conclude that the primary role of JOINTLESS is to suppress sympodial meristem identity in inflorescence meristems.

  • interactions between jointless and wild type tomato tissues during development of the Pedicel abscission zone and the inflorescence meristem
    The Plant Cell, 1999
    Co-Authors: Eugene J Szymkowiak, Erin E Irish
    Abstract:

    The jointless mutation of tomato results in the formation of flower Pedicels that lack an abscission zone and inflorescence meristems that revert to vegetative growth. We have analyzed periclinal chimeras and mericlinal sectors of jointless and wild-type tissue to determine how cells in different meristem layers (L1, L2, and L3) and their derivatives interact during these two developmental processes. Cells in the inner meristem layer, L3, alone determined whether the meristem maintained the inflorescence state or reverted to vegetative growth. Moreover, L3 derivatives determined whether a functional Pedicel abscission zone formed. Limited and disorganized autonomous development of wild-type L2-derived cells occurred when they overlay mutant tissue. Adjacent mutant and wild-type L3-derived tissues in Pedicels developed autonomously, indicating little or no lateral communication. Only the outermost L3-derived cells within the Pedicel were capable of orchestrating normal Pedicel development in overlying tissues, revealing the special status of those cells as coordinators of development for L1- and L2-derived cells, whereas the innermost L3-derived cells developed autonomously but did not influence the development of other cells.

Dragana Rančić - One of the best experts on this subject based on the ideXlab platform.

  • The application of various anatomical techniques for studying the hydraulic network in tomato fruit Pedicels
    Protoplasma, 2010
    Co-Authors: Dragana Rančić, Sofija Pekić Quarrie, Radenko Radošević, Maja Terzić, Ilinka Pećinar, Radmila Stikić, Steven Jansen
    Abstract:

    The abscission zone in fruit Pedicels plays an important role in affecting not only water uptake in the developing fruit, but also in the transport of chemical signals from root to shoot. In order to characterize the hydraulic network of tomato fruit Pedicels, we applied various techniques, including light, fluorescence microscopy, electron microscopy, maceration, tissue clearing, and X-ray computed tomography. Because of significant changes in xylem anatomy, the abscission zone in tomato fruit Pedicels is illustrated to show a clear reduction in hydraulic conductance. Based on anatomical measurements, the theoretical axial xylem conductance was calculated via the Hagen–Poiseuille law, suggesting that the hydraulic resistance of the abscission zone increases at least two orders of magnitude compared to the Pedicel zone near the stem. The advantages and shortcomings of the microscope techniques applied are discussed.

  • Comparison of light and fluorescence microscopy for xylem analysis in tomato Pedicels during fruit development.
    Journal of Microscopy, 2008
    Co-Authors: Dragana Rančić, Sofija Pekić Quarrie, Maja Terzić, S. Savić, Radmila Stikic
    Abstract:

    Summary The xylem hydraulic connection between shoot and fruits has previously been investigated, but contradictory conclusions were drawn about the presence of a flow resistance barrier in the Pedicel. In this paper we were studying effect of the drought on the functional xylem vessels in the Pedicels of tomato fruit. Commercial tomato genotype was grown in cabinet conditions under two watering regimes (full and deficit irrigation). An aqueous solution of eosin Y were used to visualize the path of water movement through tomato fruit Pedicel and fluorescence microscopy observations were done on transversal and longitudinal sections. Dye uptake studies suggested that in well watered plants and in plants exposed to drought, a large majority of xylem vessels are not functional in water transport. Reduced-irrigation treatment significantly altered number and width of functional xylem elements in the fruit Pedicel, especially in the abscission zone. This indicates that drought modifies xylem architecture and, thus, environmentally produced change in the hydraulic property of Pedicel may affect fruit development.