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Dolf Weijers - One of the best experts on this subject based on the ideXlab platform.
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Evolution, Initiation, and Diversity in Early Plant Embryogenesis.
Developmental cell, 2019Co-Authors: Tatyana Radoeva, Prasad Vaddepalli, Z M. Zhang, Dolf WeijersAbstract:During Embryogenesis in Plants, cell identities are specified de novo, starting from a single cell. By combining imaging, genomic profiling, and genetics, principles of early Plant development have been unraveled in the dicotyledonous Plant Arabidopsis. A central emerging question, however, is how well zygotic Embryogenesis in Arabidopsis reflects homologous processes in other Plant species, including early diverging, non-flowering, and non-seed Plants. Here, we consider Plant Embryogenesis with an emphasis on its evolutionary history, the diverse modes of its initiation, and the concepts in pattern formation among morphologically distinct Plant groups. Furthermore, we explore challenges and future directions in Plant Embryogenesis research.
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A Plausible Microtubule-Based Mechanism for Cell Division Orientation in Plant Embryogenesis.
Current biology : CB, 2018Co-Authors: Bandan Chakrabortty, Dolf Weijers, Viola Willemsen, De Zeeuw T, Che Yang Liao, Bela M. Mulder, Ben ScheresAbstract:Summary Oriented cell divisions are significant in Plant morphogenesis because Plant cells are embedded in cell walls and cannot relocate. Cell divisions follow various regular orientations, but the underlying mechanisms have not been clarified. We propose that cell-shape-dependent self-organization of cortical microtubule arrays is able to provide a mechanism for determining planes of early tissue-generating divisions and may form the basis for robust control of cell division orientation in the embryo. To show this, we simulate microtubules on actual cell surface shapes, from which we derive a minimal set of three rules for proper array orientation. The first rule captures the effects of cell shape alone on microtubule organization, the second rule describes the regulation of microtubule stability at cell edges, and the third rule includes the differential effect of auxin on local microtubule stability. These rules generate early embryonic division plane orientations and potentially offer a framework for understanding patterned cell divisions in Plant morphogenesis.
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A microtubule-based mechanism predicts cell division orientation in Plant Embryogenesis
2018Co-Authors: Bandan Chakrabortty, Dolf Weijers, Willemsen, De Zeeuw T, Che Yang Liao, Bela M. Mulder, Ben ScheresAbstract:Oriented cell divisions are significant in Plant morphogenesis because Plant cells are embedded in cell walls and cannot relocate. Cell divisions follow various regular orientations, but the underlying mechanisms have not been clarified. We show that cell-shape dependent self-organisation of cortical microtubule arrays is crucial for determining planes of early tissue-generating divisions and forms the basis for robust control of cell division orientation in the embryo. To achieve this, we simulate microtubules on actual cell surface shapes from which we derive a minimal set of three rules for proper array orientation. The first rule captures the effects of cell shape alone on microtubule organisation, the second rule describes the regulation of microtubule stability at cell edges and the third rule includes the differential effect of auxin on local microtubule stability. These rules explain early embryonic division plane orientations and offer a framework for understanding patterned cell divisions in Plant morphogenesis.
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Plant Embryogenesis requires aux lax mediated auxin influx
Development, 2015Co-Authors: Hélène S. Robert, Kim Boutilier, Dolf Weijers, Wim Grunewald, Michael Sauer, Bernard Cannoot, Mercedes Soriano, Ranjan Swarup, Malcolm J. Bennett, Jiri FrimlAbstract:The Plant hormone auxin and its directional transport are known to play a crucial role in defining the embryonic axis and subsequent development of the body plan. Although the role of PIN auxin efflux transporters has been clearly assigned during embryonic shoot and root specification, the role of the auxin influx carriers AUX1 and LIKE-AUX1 (LAX) proteins is not well established. Here, we used chemical and genetic tools on Brassica napus microspore-derived embryos and Arabidopsis thaliana zygotic embryos, and demonstrate that AUX1, LAX1 and LAX2 are required for both shoot and root pole formation, in concert with PIN efflux carriers. Furthermore, we uncovered a positive-feedback loop between MONOPTEROS (ARF5)-dependent auxin signalling and auxin transport. This MONOPTEROS-dependent transcriptional regulation of auxin influx (AUX1, LAX1 and LAX2) and auxin efflux (PIN1 and PIN4) carriers by MONOPTEROS helps to maintain proper auxin transport to the root tip. These results indicate that auxin-dependent cell specification during embryo development requires balanced auxin transport involving both influx and efflux mechanisms, and that this transport is maintained by a positive transcriptional feedback on auxin signalling.
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Plant Embryogenesis requires AUX/LAX-mediated auxin influx
Development (Cambridge England), 2015Co-Authors: Hélène S. Robert, Kim Boutilier, Dolf Weijers, Wim Grunewald, Michael Sauer, Bernard Cannoot, Mercedes Soriano, Ranjan Swarup, Malcolm J. Bennett, Jiri FrimlAbstract:The Plant hormone auxin and its directional transport are known to play a crucial role in defining the embryonic axis and subsequent development of the body plan. Although the role of PIN auxin efflux transporters has been clearly assigned during embryonic shoot and root specification, the role of the auxin influx carriers AUX1 and LIKE-AUX1 (LAX) proteins is not well established. Here, we used chemical and genetic tools on Brassica napus microspore-derived embryos and Arabidopsis thaliana zygotic embryos, and demonstrate that AUX1, LAX1 and LAX2 are required for both shoot and root pole formation, in concert with PIN efflux carriers. Furthermore, we uncovered a positive-feedback loop between MONOPTEROS (ARF5)-dependent auxin signalling and auxin transport. This MONOPTEROS-dependent transcriptional regulation of auxin influx (AUX1, LAX1 and LAX2) and auxin efflux (PIN1 and PIN4) carriers by MONOPTEROS helps to maintain proper auxin transport to the root tip. These results indicate that auxin-dependent cell specification during embryo development requires balanced auxin transport involving both influx and efflux mechanisms, and that this transport is maintained by a positive transcriptional feedback on auxin signalling.
David W. Meinke - One of the best experts on this subject based on the ideXlab platform.
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Development of the Suspensor: Differentiation, Communication, and Programmed Cell Death During Plant Embryogenesis
Advances in Cellular and Molecular Biology of Plants, 1997Co-Authors: Brian W. Schwartz, Daniel M. Vernon, David W. MeinkeAbstract:The suspensor functions early in Embryogenesis to provide physical support, nutrition, and growth regulators to the developing embryo proper. In most Plants, the suspensor is derived from the basal cell produced following asymmetric division of the zygote. Cellular differences between the suspensor and embryo proper may result from morphogenetic gradients established prior to division of the zygote. The suspensor develops rapidly with respect to the embryo proper and becomes the first differentiated embryonic structure produced during seed development. The suspensor later undergoes programmed cell death and is not present in mature seeds. Several abnormal suspensor mutants of Arabidopsis have been identified in which the suspensor fails to undergo programmed cell death and instead proliferates to form a structure with features characteristic of the embryo proper. Analysis of these mutants suggests that communication with the embryo proper is required early in Embryogenesis for maintenance of suspensor cell identity and later in suspensor development for initiation of programmed cell death. The pattern of embryogenic transformation observed in these mutants indicates that suspensor cells have the potential to recapitulate the entire spectrum of developmental programs normally restricted to the embryo proper. During normal development, interactions with the embryo proper appear to inhibit embryogenic programs, allowing suspensor cell identity to be maintained. Based on these observations, we propose that negative regulation of developmental potential plays a major role in suspensor cell differentiation and that the suspensor may serve as a valuable system for addressing mechanisms of cell differentiation and cellular communication during Plant development.
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Molecular genetics of Plant Embryogenesis
Annual Review of Plant Physiology and Plant Molecular Biology, 1995Co-Authors: David W. MeinkeAbstract:Embryogenesis is a complex devel opmental pathway that plays a central role in the life cycle of higher Plants. Recent advances in the application of genetics and molecular biology to the study of developmental processes in animals have led to a renewed interest in the analysis of Plant development and the identification of genes with important functions during Plant Embryogenesis. The most extensive studies
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Diversity of Embryonic Mutants Identified Following Agrobanterium Mediated Seed Transformation in Arabidopsis thaliana
Plant Molecular Biology, 1994Co-Authors: David W. MeinkeAbstract:Arabidopsis thaliana has clearly become the model system of choice for a wide range of studies in Plant developmental and molecular genetics (Koncz et al. 1992; NSF Publication 92–112; Meinke 1993). My laboratory has for many years pursued the use of Arabidopsis as a model system for genetic analysis of Plant Embryogenesis (Meinke and Sussex 1979). My approach was based initially on the pioneering work of Andreas Muller (1963). The history of this field has been the subject of several extensive reviews (Meinke 1991a, b; Lindsey and Topping 1993). The purpose of this minireview will be to focus primarily on the isolation and characterization of T-DNA insertional mutants of Arabidopsis with defects in embryo development. Additional details on these mutants can be obtained from recent publications (Errampalli et al. 1991? Castle and Meinke 1993; Castle et al. 1993).
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A Homoeotic Mutant of Arabidopsis thaliana with Leafy Cotyledons
Science, 1992Co-Authors: David W. MeinkeAbstract:Cotyledons are specialized leaves produced during Plant Embryogenesis. Cotyledons and leaves typically differ in morphology, ultrastructure, and patterns of gene expression. The leafy cotyledon ( Iec ) mutant of Arabidopsis thaliana fails to maintain this distinction between embryonic and vegetative patterns of Plant development. Mutant embryos are phenotypically abnormal, occasionally viviparous, and intolerant of desiccation. Mutant cotyledons produce trichomes characteristic of leaves, lack embryo-specific protein bodies, and exhibit a vascular pattern intermediate between that of leaves and cotyledons. These results suggest that lec cotyledons are partially transformed into leaves and that the wild-type gene ( LEC ) functions to activate a wide range of embryo-specific pathways in higher Plants.
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Perspectives on Genetic Analysis of Plant Embryogenesis.
The Plant cell, 1991Co-Authors: David W. MeinkeAbstract:Embryogenesis plays a central role in the life cycle of flowering Plants. Ever since the process of double fertilization was documented at the turn of the century, Plant embryologists have attempted to characterize the cellular and biochemical changes that occur within developing seeds (Maheshwari, 1950; Raghavan, 1976). For many years, the emphasis was on comparative morphology and the analysis of cell division patterns during early stages of embryo development (Johansen, 1950; Wardlaw, 1955). Attention then shifted to experimental studies of somatic Embryogenesis, embryo culture, and haploid embryos derived from microspores (Raghavan, 1986). Manipulation of zygotic embryos was limited by the presence of surrounding maternal tissues. Electron microscopy provided additional details on cellular changes associated with Embryogenesis but generally failed to identify the mechanisms responsible. Plant embryologists believed that genetic factors played an important role in morphogenesis, but mutants with altered patterns of embryo development were largely ignored (Meinke, 1986). Recent advances in molecular biology have led to a renewed interest in Plant embryology and the underlying patterns of gene expression that occur throughout seed development (Goldberg et al., 1989). Many genes transcribed during embryonic maturation have now been examined at the molecular level. Genetics provides a complementary approach to the study of Plant embryo development by allowing the identification of genes with essential functions during this critical stage of the life cycle (Meinke, 1986). The purpose of this review will be to explore the potential benefits and limitations of mutant analysis in relation to Plant embryo development. Additional information can be obtained through recent reviews on Plant development (Steeves and Sussex, 1989; Lyndon, 1990), experimental Plant Embryogenesis (Johri, 1984; Raghavan, 1986; Williams and Maheswaran, 1986), and Plant developmental genetics (Sheridan, 1988; Meinke, 1991a, 1991b). Plant embryologists originally attempted to explain characteristic patterns of cell division observed early in development by establishing fundamental laws of embryogeny (Johansen, 1950). These laws of parsimony, numbers, origin, disposition, and destination were thought to reflect the fundamental organization of embryos from different species. This view has gradually been replaced by the realization that cell division patterns are determined more by genetic and biophysical factors than by laws of embryogeny. Examination of developmental pathways in different angiosperms has nevertheless revealed a number of common features. The most critical events appear to be the formation of apical meristems, the establishment of basic patterns of symmetry and cellular organization, and the transition from a heterotrophic zygote dependent upon nutrient reserves of surrounding maternal tissues to an autotrophic embryo capable of surviving desiccation and producing a viable seedling after germination. Early stages of Plant embryo development are characterized by cell division and morphogenesis. This is followed by a period of cell specialization and embryonic maturation in preparation for dormancy and germination. Several features distinguish Embryogenesis in angiosperms from related pathways in animal systems: (1) the process of double fertilization and subsequent interactions between embryo and endosperm tissues, (2) the apparently minor role played by maternal mRNAs stored in unfertilized eggs, (3) the absence of cellular migration during embryo development, (4) the absence of a germ line established early in development, (5) the activation of large numbers of zygotic genes during very early stages of Embryogenesis, (6) the presence of a male gametophyte active in transcription that leads to elimination of many deleterious alleles before fertilization, (7) the establishment of relatively few specialized cell types, (8) the formation of apical meristems that ultimately produce the adult Plant, and (9) the small size of the zygote and its location deep within maternal tissues. The zygote in flowering Plants is also not unique; a wide range of somatic cells can be
Peter V. Bozhkov - One of the best experts on this subject based on the ideXlab platform.
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Comprar Plant Embryogenesis | Fernanda Suarez, Maria | 9781588299314 | Springer
2008Co-Authors: Maria F. Suarez, Peter V. BozhkovAbstract:Tienda online donde Comprar Plant Embryogenesis al precio 83,74 € de Fernanda Suarez, Maria | Bozhkov, Peter, tienda de Libros de Medicina, Libros de Medicina Familiar y Comunitaria/General - Medicina general
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Cysteine protease mcII-Pa executes programmed cell death during Plant Embryogenesis
Proceedings of the National Academy of Sciences of the United States of America, 2005Co-Authors: Peter V. Bozhkov, Salvador Rodriguez-nieto, Andrey A. Zamyatnin, Maria F. Suarez, Lada Filonova, Geoffrey Daniel, Boris Zhivotovsky, Andrei P. SmertenkoAbstract:Programmed cell death (PCD) is indispensable for eukaryotic development. In animals, PCD is executed by the caspase family of cysteine proteases. Plants do not have close homologues of caspases but possess a phylogenetically distant family of cysteine proteases named metacaspases. The cellular function of metacaspases in PCD is unknown. Here we show that during Plant Embryogenesis, metacaspase mcII-Pa translocates from the cytoplasm to nuclei in terminally differentiated cells that are destined for elimination, where it colocalizes with the nuclear pore complex and chromatin, causing nuclear envelope disassembly and DNA fragmentation. The cell-death function of mcII-Pa relies on its cysteine-dependent arginine-specific proteolytic activity. Accordingly, mutation of catalytic cysteine abrogates the proteolytic activity of mcII-Pa and blocks nuclear degradation. These results establish metacaspase as an executioner of PCD during embryo patterning and provide a functional link between PCD and Embryogenesis in Plants. Although mcII-Pa and metazoan caspases have different substrate specificity, they serve a common function during development, demonstrating the evolutionary parallelism of PCD pathways in Plants and animals.
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Regulation of programmed cell death in Plant Embryogenesis
BMC Plant Biology, 2005Co-Authors: Peter V. BozhkovAbstract:As Plants grow they not only form new tissues and structures using highly coordinated cell-division and cell-differentiation programs but also continuously kill many of their own cells through activation of programmed cell death (PCD). The earliest functions of PCD in Plant life are fulfilled during Embryogenesis. Here PCD governs two major developmental processes. First is the elimination of a transient embryonic structure – suspensor, which functions at early stages of embryo development as a conduit of nutrients and growth factors, but is not required at later stages [1]. Another function of embryonic PCD applies to embryo abortion, which is not only a response to stress or mutagens, but also a normal feature of those Plant species, which produce polyembryonic seeds. In the latter case competition among multiple embryos for survival often induces PCD resulting in the elimination of all but one embryo in a seed [2]. At the demise, both suspensor and entire embryos display a gradient of successive stages of PCD along apical-to-basal axis [2,3]. This PCD implicates active role of autophagy in complete removal of cell protoplast. Autophagosomes are formed via Golgi and proplastids [1]. Autophagocytosis depends on the dynamic reorganization of the cytoskeleton. Microtubule network is disrupted early in PCD pathway. F-actin is gradually reorganised into thick longitudinal cables and is present till the vacuole collapse and fragmentation of nuclear DNA [1,3]. Type II metacapase is critically involved in the regulation of the cell death pathway, which is essential for normal embryo development. Metacaspase gene silencing results in the suppression of cell death and failure of embryonic pattern formation [4].
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Programmed cell death in Plant Embryogenesis.
Current topics in developmental biology, 2005Co-Authors: Peter V. Bozhkov, Lada Filonova, Maria F. SuarezAbstract:Successful embryonic development in Plants, as in animals, requires a strict coordination of cell proliferation, cell differentiation, and cell-death programs. The role of cell death is especially critical for the establishment of polarity at early stages of Plant Embryogenesis, when the differentiation of the temporary structure, the suspensor, is followed by its programmed elimination. Here, we review the emerging knowledge of this and other functions of programmed cell death during Plant Embryogenesis, as revealed by developmental analyses of Arabidopsis embryo-specific mutants and gymnosperm (spruce and pine) model embryonic systems. Cell biological studies in these model systems have helped to identify and order the cellular processes occurring during self-destruction of the embryonic cells. While metazoan embryos can recruit both apoptotic and autophagic cell deaths, the ultimate choice depending on the developmental task and conditions, Plant embryos use autophagic cell disassembly as a single universal cell-death pathway. Dysregulation of this pathway leads to aberrant or arrested embryo development. We address the role of distinct cellular components in the execution of the autophagic cell death, and outline an overall mechanistic view of how cells are eliminated during Plant embryonic pattern formation. Finally, we discuss the possible roles of some of the candidate Plant cell-death proteins in the regulation of developmental cell death.
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VEIDase is a principal caspase-like activity involved in Plant programmed cell death and essential for embryonic pattern formation
Cell death and differentiation, 2003Co-Authors: Peter V. Bozhkov, Andrei P. Smertenko, Maria F. Suarez, Lada Filonova, Boris Zhivotovsky, Andreas Helmersson, S. Von ArnoldAbstract:Plant Embryogenesis is intimately associated with programmed cell death. The mechanisms of initiation and control of programmed cell death during Plant embryo development are not known. Proteolytic activity associated with caspase-like proteins is paramount for control of programmed cell death in animals and yeasts. Caspase family of proteases has unique strong preference for cleavage of the target proteins next to asparagine residue. In this work, we have used synthetic peptide substrates containing caspase recognition sites and corresponding specific inhibitors to analyse the role of caspase-like activity in the regulation of programmed cell death during Plant Embryogenesis. We demonstrate that VEIDase is a principal caspase-like activity implicated in Plant Embryogenesis. This activity increases at the early stages of embryo development that coincide with massive cell death during shape remodeling. The VEIDase activity exhibits high sensitivity to pH, ionic strength and Zn2+ concentration. Altogether, biochemical assays show that VEIDase Plant caspase-like activity resembles that of both mammalian caspase-6 and yeast metacaspase, YCA1. In vivo, VEIDase activity is localised specifically in the embryonic cells during both the commitment and in the beginning of the execution phase of programmed cell death. Inhibition of VEIDase prevents normal embryo development via blocking the embryo-suspensor differentiation. Our data indicate that the VEIDase activity is an integral part in the control of Plant developmental cell death programme, and that this activity is essential for the embryo pattern formation.
Claudio Stasolla - One of the best experts on this subject based on the ideXlab platform.
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Dying with Style: Death Decision in Plant Embryogenesis.
Methods in molecular biology (Clifton N.J.), 2016Co-Authors: Shuanglong Huang, Mohamed M. Mira, Claudio StasollaAbstract:Embryogenesis is a fascinating event during the Plant life cycle encompassing several steps whereby the zygote develops into a fully developed embryo which, in angiosperms, is composed of an axis separating the apical meristems, and two cotyledons. Recapitulation of Embryogenesis can also occur in vitro through somatic Embryogenesis, where somatic cells are induced to form embryos, and androgenesis, in which embryos originate from immature male gametophytes. Besides cell division and differentiation, embryo patterning in vivo and in vitro requires the dismantling and selective elimination of cells and tissues via programmed cell death (PCD). While the manifestation of the death program has long been acknowledged in vivo, especially in relation to the elimination of the suspensor during the late phases of embryo development, PCD during in vitro Embryogenesis has only been described in more recent years. Independent studies using the gymnosperm Norway spruce and the angiosperm maize have shown that the death program is crucial for the proper formation and further development of immature somatic embryos. This chapter summarizes the recent advances in the field of PCD during Embryogenesis and proposes novel regulatory mechanisms activating the death program in Plants.
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ROS Signalling in Plant Embryogenesis
Signaling and Communication in Plants, 2014Co-Authors: Mohamed Elhiti, Claudio StasollaAbstract:Plant somatic Embryogenesis is the ability of somatic and/or gametophytic cells to produce embryos capable of regenerating into viable Plants. The expression of embryonic competence is manifested following precise manipulations of culture conditions often requiring applications of Plant growth regulators and the imposition of stress conditions in the form of heat and/or cold treatments. Reactive oxygen species (ROS) are considered ubiquitous endogenous signals in Plant systems, playing significant roles in a wide range of responses to environmental and endogenous factors. Accumulating evidence indicates that somatic Embryogenesis is influenced by ROS. Although still partially unknown, the mechanisms underlying the cross talk between ROS and somatic Embryogenesis have been investigated in a number of Plant species. The focus of this chapter is to summarize information related to the role of ROS homeostasis and signalling on the induction and development of in vitro-produced embryos.
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hemoglobin control of cell survival death decision regulates in vitro Plant Embryogenesis
Plant Physiology, 2014Co-Authors: Shuanglong Huang, Owen S. D. Wally, Robert D. Hill, Giuseppe Dionisio, Belay T. Ayele, Sravan Kumar Jami, Claudio StasollaAbstract:Programmed cell death (PCD) in multicellular organisms is a vital process in growth, development, and stress responses that contributes to the formation of tissues and organs. Although numerous studies have defined the molecular participants in apoptotic and PCD cascades, successful identification of early master regulators that target specific cells to live or die is limited. Using Zea mays somatic Embryogenesis as a model system, we report that the expressions of two Plant hemoglobin (Hb) genes (ZmHb1 and ZmHb2) regulate the cell survival/death decision that influences somatic Embryogenesis through their cell-specific localization patterns. Suppression of either of the two ZmHbs is sufficient to induce PCD through a pathway initiated by elevated NO and Zn2+ levels and mediated by production of reactive oxygen species. The effect of the death program on the fate of the developing embryos is dependent on the localization patterns of the two ZmHbs. During somatic Embryogenesis, ZmHb2 transcripts are restricted to a few cells anchoring the embryos to the subtending embryogenic tissue, whereas ZmHb1 transcripts extend to several embryonic domains. Suppression of ZmHb2 induces PCD in the anchoring cells, allowing the embryos to develop further, whereas suppression of ZmHb1 results in massive PCD, leading to abortion. We conclude that regulation of the expression of these ZmHbs has the capability to determine the developmental fate of the embryogenic tissue during somatic Embryogenesis through their effect on PCD. This unique regulation might have implications for development and differentiation in other species.
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Hemoglobin control of cell survival/death decision regulates in vitro Plant Embryogenesis
Plant physiology, 2014Co-Authors: Shuanglong Huang, Owen S. D. Wally, Robert D. Hill, Giuseppe Dionisio, Belay T. Ayele, Sravan Kumar Jami, Claudio StasollaAbstract:Programmed cell death (PCD) in multicellular organisms is a vital process in growth, development, and stress responses that contributes to the formation of tissues and organs. Although numerous studies have defined the molecular participants in apoptotic and PCD cascades, successful identification of early master regulators that target specific cells to live or die is limited. Using Zea mays somatic Embryogenesis as a model system, we report that the expressions of two Plant hemoglobin (Hb) genes (ZmHb1 and ZmHb2) regulate the cell survival/death decision that influences somatic Embryogenesis through their cell-specific localization patterns. Suppression of either of the two ZmHbs is sufficient to induce PCD through a pathway initiated by elevated NO and Zn2+ levels and mediated by production of reactive oxygen species. The effect of the death program on the fate of the developing embryos is dependent on the localization patterns of the two ZmHbs. During somatic Embryogenesis, ZmHb2 transcripts are restricted to a few cells anchoring the embryos to the subtending embryogenic tissue, whereas ZmHb1 transcripts extend to several embryonic domains. Suppression of ZmHb2 induces PCD in the anchoring cells, allowing the embryos to develop further, whereas suppression of ZmHb1 results in massive PCD, leading to abortion. We conclude that regulation of the expression of these ZmHbs has the capability to determine the developmental fate of the embryogenic tissue during somatic Embryogenesis through their effect on PCD. This unique regulation might have implications for development and differentiation in other species.
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Hemoglobin regulation of Plant Embryogenesis and Plant pathogen interaction
Plant signaling & behavior, 2013Co-Authors: Owen S. D. Wally, Mohamed M. Mira, Robert D. Hill, Claudio StasollaAbstract:Plant hemoglobins are ubiquitous molecules involved in several aspects of Plant development and stress responses. Studies on the functional aspects of Plant hemoglobins at the cellular level in these processes are limited, despite their ability to scavenge nitric oxide (NO), an important signal molecule interfering with hormone synthesis and sensitivity. This mini-review summarizes current knowledge on Plant hemoglobins, analyzes their participation in Plant pathogen interaction and Embryogenesis and proposes a possible model centering on jasmonic acid (JA) as a downstream component of hemoglobin responses.
Maria F. Suarez - One of the best experts on this subject based on the ideXlab platform.
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Comprar Plant Embryogenesis | Fernanda Suarez, Maria | 9781588299314 | Springer
2008Co-Authors: Maria F. Suarez, Peter V. BozhkovAbstract:Tienda online donde Comprar Plant Embryogenesis al precio 83,74 € de Fernanda Suarez, Maria | Bozhkov, Peter, tienda de Libros de Medicina, Libros de Medicina Familiar y Comunitaria/General - Medicina general
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Cysteine protease mcII-Pa executes programmed cell death during Plant Embryogenesis
Proceedings of the National Academy of Sciences of the United States of America, 2005Co-Authors: Peter V. Bozhkov, Salvador Rodriguez-nieto, Andrey A. Zamyatnin, Maria F. Suarez, Lada Filonova, Geoffrey Daniel, Boris Zhivotovsky, Andrei P. SmertenkoAbstract:Programmed cell death (PCD) is indispensable for eukaryotic development. In animals, PCD is executed by the caspase family of cysteine proteases. Plants do not have close homologues of caspases but possess a phylogenetically distant family of cysteine proteases named metacaspases. The cellular function of metacaspases in PCD is unknown. Here we show that during Plant Embryogenesis, metacaspase mcII-Pa translocates from the cytoplasm to nuclei in terminally differentiated cells that are destined for elimination, where it colocalizes with the nuclear pore complex and chromatin, causing nuclear envelope disassembly and DNA fragmentation. The cell-death function of mcII-Pa relies on its cysteine-dependent arginine-specific proteolytic activity. Accordingly, mutation of catalytic cysteine abrogates the proteolytic activity of mcII-Pa and blocks nuclear degradation. These results establish metacaspase as an executioner of PCD during embryo patterning and provide a functional link between PCD and Embryogenesis in Plants. Although mcII-Pa and metazoan caspases have different substrate specificity, they serve a common function during development, demonstrating the evolutionary parallelism of PCD pathways in Plants and animals.
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Programmed cell death in Plant Embryogenesis.
Current topics in developmental biology, 2005Co-Authors: Peter V. Bozhkov, Lada Filonova, Maria F. SuarezAbstract:Successful embryonic development in Plants, as in animals, requires a strict coordination of cell proliferation, cell differentiation, and cell-death programs. The role of cell death is especially critical for the establishment of polarity at early stages of Plant Embryogenesis, when the differentiation of the temporary structure, the suspensor, is followed by its programmed elimination. Here, we review the emerging knowledge of this and other functions of programmed cell death during Plant Embryogenesis, as revealed by developmental analyses of Arabidopsis embryo-specific mutants and gymnosperm (spruce and pine) model embryonic systems. Cell biological studies in these model systems have helped to identify and order the cellular processes occurring during self-destruction of the embryonic cells. While metazoan embryos can recruit both apoptotic and autophagic cell deaths, the ultimate choice depending on the developmental task and conditions, Plant embryos use autophagic cell disassembly as a single universal cell-death pathway. Dysregulation of this pathway leads to aberrant or arrested embryo development. We address the role of distinct cellular components in the execution of the autophagic cell death, and outline an overall mechanistic view of how cells are eliminated during Plant embryonic pattern formation. Finally, we discuss the possible roles of some of the candidate Plant cell-death proteins in the regulation of developmental cell death.
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VEIDase is a principal caspase-like activity involved in Plant programmed cell death and essential for embryonic pattern formation
Cell death and differentiation, 2003Co-Authors: Peter V. Bozhkov, Andrei P. Smertenko, Maria F. Suarez, Lada Filonova, Boris Zhivotovsky, Andreas Helmersson, S. Von ArnoldAbstract:Plant Embryogenesis is intimately associated with programmed cell death. The mechanisms of initiation and control of programmed cell death during Plant embryo development are not known. Proteolytic activity associated with caspase-like proteins is paramount for control of programmed cell death in animals and yeasts. Caspase family of proteases has unique strong preference for cleavage of the target proteins next to asparagine residue. In this work, we have used synthetic peptide substrates containing caspase recognition sites and corresponding specific inhibitors to analyse the role of caspase-like activity in the regulation of programmed cell death during Plant Embryogenesis. We demonstrate that VEIDase is a principal caspase-like activity implicated in Plant Embryogenesis. This activity increases at the early stages of embryo development that coincide with massive cell death during shape remodeling. The VEIDase activity exhibits high sensitivity to pH, ionic strength and Zn2+ concentration. Altogether, biochemical assays show that VEIDase Plant caspase-like activity resembles that of both mammalian caspase-6 and yeast metacaspase, YCA1. In vivo, VEIDase activity is localised specifically in the embryonic cells during both the commitment and in the beginning of the execution phase of programmed cell death. Inhibition of VEIDase prevents normal embryo development via blocking the embryo-suspensor differentiation. Our data indicate that the VEIDase activity is an integral part in the control of Plant developmental cell death programme, and that this activity is essential for the embryo pattern formation.