The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
William J Lucas - One of the best experts on this subject based on the ideXlab platform.
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the Plant Vascular System ii from essential functions in resource allocation inter organ communication and defense to evolution of the monocot cambium
Journal of Integrative Plant Biology, 2017Co-Authors: William J LucasAbstract:In this Special Issue, a focus is also placed on the role of the xylem as an essential conduit for the long-distance delivery of water and mineral nutrients from the soil to the vegetative (above-ground) regions of the Plant. Xylem cells destined to form tracheids or vessel members, which will make up the conduit for this water and mineral transport from the roots to the shoots, undergo apoptosis, a process of programmed cell death. In their review, Venturas et al. (2017) provide an in-depth analysis of the processes underlying the passage of water through these mature, and thus, dead, xylem conducting cells. They elegantly describe the physics associated with this transport of water from the soil to the above-ground tissues and organs of the Plant. A tensional gradient, within the water column, pulls the transpiration stream through the Plant and Venturas et al. (2017) address the challenges that this presents to the Plant, including the unthinkable, in that the water column can rupture, a process termed cavitation. The authors provide an up-to-date analysis of the debate as to how Plants might refill such cavitated xylem cells, an important topic with respect to tissue hydraulics. This review closes with an insightful section on the impact of climate change on xylem function.
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Phloem-Mobile RNAs as Systemic Signaling Agents
Annual Review of Plant Biology, 2017Co-Authors: William J LucasAbstract:The Plant Vascular System plays a central role in coordinating physiological and developmental events through delivery of both essential nutrients and long-distance signaling agents. The enucleate phloem sieve tube System of the angiosperms contains a broad spectrum of RNA species. Grafting and transcriptomics studies have indicated that several thousand mRNAs move long distances from source organs to meristematic sink tissues. Ribonucleoprotein complexes play a pivotal role as stable RNA-delivery Systems for Systemic translocation of cargo RNA. In this review, we assess recent progress in the characterization of phloem and plasmodesmal transport as an integrated local and Systemic communication network. We discuss the roles of phloem-mobile small RNAs in epigenetic events, including meristem development and genome stability, and the delivery of mRNAs to specific tissues in response to environmental inputs. A large body of evidence now supports a model in which phloem-mobile RNAs act as critical component...
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Proteomics and metabolomics analyses reveal the cucurbit sieve tube System as a complex metabolic space.
Plant Journal, 2016Co-Authors: Chaoyang Hu, Hattem M. El-shabrawi, Danny Alexander, Dabing Zhang, John A. Ryals, William J LucasAbstract:Summary The Plant Vascular System, and specifically the phloem, plays a pivotal role in allocation of fixed carbon to developing sink organs. Although the processes involved in loading and unloading of sugars and amino acids are well characterized, little information is available regarding the nature of other metabolites in the sieve tube System (STS) at specific sites along the pathway. Here, we elucidate spatial features of metabolite composition mapped with phloem enzymes along the cucurbit STS. Phloem sap (PS) was collected from the loading (source), unloading (apical sink region) and shoot–root junction regions of cucumber, watermelon and pumpkin. Our PS analyses revealed significant differences in the metabolic and proteomic profiles both along the source–sink pathway and between the STSs of these three cucurbits. In addition, metabolite profiles established for PS and Vascular tissue indicated the presence of distinct compositions, consistent with the operation of the STS as a unique symplasmic domain. In this regard, at various locations along the STS we could map metabolites and their related enzymes to specific metabolic pathways. These findings are discussed with regard to the function of the STS as a unique and highly complex metabolic space within the Plant Vascular System.
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Vascular-mediated signalling involved in early phosphate stress response in Plants
Nature Plants, 2016Co-Authors: Zhaoliang Zhang, Yi Zheng, Jieyu Chen, Akiko Yoshida, Leon V. Kochian, William J LucasAbstract:Signalling events of early phosphate (P_i) stress in Plants are not well known. A study combining transcriptome analyses and grafting experiments now reveals tissue-specific transcriptomic responses to early P_i stress, and a major role for the Vascular System in this process. Depletion of finite global rock phosphate (P_i) reserves will impose major limitations on future agricultural productivity and food security. Hence, modern breeding programmes seek to develop P_i-efficient crops with sustainable yields under reduced P_i fertilizer inputs. In this regard, although the long-term responses of Plants to P_i stress are well documented, the early signalling events have yet to be elucidated. Here, we show Plant tissue-specific responses to early P_i stress at the transcription level and a predominant role of the Plant Vascular System in this process. Specifically, imposition of P_i stress induces rapid and major changes in the mRNA population in the phloem translocation stream, and grafting studies have revealed that many hundreds of phloem-mobile mRNAs are delivered to specific sink tissues. We propose that the shoot Vascular System acts as the site of root-derived P_i stress perception, and the phloem serves to deliver a cascade of signals to various sinks, presumably to coordinate whole-Plant P_i homeostasis.
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A tomato phloem-mobile protein regulates the shoot-to-root ratio by mediating the auxin response in distant organs.
Plant Journal, 2015Co-Authors: Ziv Spiegelman, William J Lucas, Siobhan M Brady, Zhaoliang Zhang, Yi Zheng, Ted Toal, Shmuel WolfAbstract:Summary The Plant Vascular System serves as a conduit for delivery of both nutrients and signaling molecules to various distantly located organs. The anucleate sieve tube System of the angiosperm phloem delivers sugars and amino acids to developing organs, and has recently been shown to contain a unique population of RNA and proteins. Grafting studies have established that a number of these macromolecules are capable of moving long distances between tissues, thus providing support for operation of a phloem-mediated inter-organ communication network. Currently, our knowledge of the roles played by such phloem-borne macromolecules is in its infancy. Here, we show that, in tomato, translocation of a phloem-mobile cyclophilin, SlCyp1, from a wild-type scion into a mutant rootstock results in restoration of Vascular development and lateral root initiation. This process occurs through reactivation of auxin response pathways and reprogramming of the root transcriptome. Moreover, we show that long-distance trafficking of SlCyp1 is associated with regulation of the shoot-to-root ratio in response to changing light intensities, by modulating root growth. We conclude that long-distance trafficking of SlCyp1 acts as a rheostat to control the shoot-to-root ratio, by mediating root development to integrate photosynthesis and light intensity with requirements for access to water and mineral nutrients.
Patrick Achard - One of the best experts on this subject based on the ideXlab platform.
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long distance transport of phytohormones through the Plant Vascular System
Current Opinion in Plant Biology, 2016Co-Authors: Benoit Lacombe, Patrick AchardAbstract:Phytohormones are a group of low abundance molecules that activate various metabolic and developmental processes in response to environmental and endogenous signals. Like animal hormones, Plant hormones often have distinct source and target tissues, hence ensuring long-range communication at the whole-Plant level. Plants rely on various hormone distribution mechanisms depending on the distance and the direction of the transport. Here, we highlight the recent findings on the long-distance movement of Plant hormones within the vasculature, from the physiological role to the molecular mechanism of the transport.
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Long-distance transport of endogenous gibberellins in Arabidopsis
Plant Signaling & Behavior, 2016Co-Authors: Thomas Regnault, Jean-michel Davière, Patrick AchardAbstract:Gibberellins (GAs) are phytohormones controlling major aspects of Plant growth and development. Although previous studies suggested the existence of a transport of GAs in Plants, the nature and properties associated with this transport were unknown. We recently showed through micrografting and biochemical approaches that the GA12 precursor is the chemical form of GA undergoing long-distance transport across Plant organs in Arabidopsis. Endogenous GA12 moves through the Plant Vascular System from production sites to recipient tissues, in which GA12 can be converted to bioactive forms to support growth via the activation of GA-dependent processes. GAs are also essential to promote seed germination; hence GA biosynthesis mutants do not germinate without exogenous GA treatment. Our results suggest that endogenous GAs are not (or not sufficiently) transmitted to the offspring to successfully complete the germination under permissive conditions.
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The gibberellin precursor GA_12 acts as a long-distance growth signal in Arabidopsis
Nature Plants, 2015Co-Authors: Thomas Regnault, Jean-michel Davière, Michael Wild, Lali Sakvarelidze-achard, Dimitri Heintz, Esther Carrera Bergua, Isabel Lopez Diaz, Fan Gong, Peter Hedden, Patrick AchardAbstract:Gibberellin is a major hormone in Plant growth. Mixing old-style grafting with modern molecular genetics in Arabidopsis shows that the GA_12 precursor is the chemical form of gibberellin undergoing long-distance transport across Plant organs. The gibberellin (GA) phytohormones play important roles in Plant growth and development, promoting seed germination, elongation growth and reproductive development^ 1 . Over the years, substantial progress has been made in understanding the regulation of GA signalling and metabolism, which ensures appropriate levels of GAs for growth and development^ 2 . Moreover, an additional level of regulation may reside in the transport of GAs from production sites to recipient tissues that require GAs for growth. Although there is considerable evidence suggesting the existence of short- and long-distance movement of GAs in Plants^ 3 – 8 , the nature and the biological properties of this transport are not yet understood. Here, we combine biochemical and conventional micrografting experiments in Arabidopsis thaliana to show that the GA precursor GA_12, although biologically inactive by itself, is the major mobile GA signal over long distances. Quantitative analysis of endogenous GAs in xylem and phloem exudates further indicates that GA_12 moves through the Plant Vascular System. Finally, we demonstrate that GA_12 is functional in recipient tissues, supporting growth via the activation of the GA signalling cascade. Collectively, these results reveal the existence of long-range transport of endogenous GA_12 in Plants that may have implications for the control of developmental phase transitions and the adaptation to adverse environments.
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The gibberellin precursor GA12 acts as a long-distance growth signal in Arabidopsis
Nature plants, 2015Co-Authors: Thomas Regnault, Jean-michel Davière, Michael Wild, Lali Sakvarelidze-achard, Dimitri Heintz, Fan Gong, Peter Hedden, Esther Carrera Bergua, Isabel Díaz, Patrick AchardAbstract:The gibberellin (GA) phytohormones play important roles in Plant growth and development, promoting seed germination, elongation growth and reproductive development1. Over the years, substantial progress has been made in understanding the regulation of GA signalling and metabolism, which ensures appropriate levels of GAs for growth and development2. Moreover, an additional level of regulation may reside in the transport of GAs from production sites to recipient tissues that require GAs for growth. Although there is considerable evidence suggesting the existence of short- and long-distance movement of GAs in Plants3–8, the nature and the biological properties of this transport are not yet understood. Here, we combine biochemical and conventional micrografting experiments in Arabidopsis thaliana to show that the GA precursor GA12, although biologically inactive by itself, is the major mobile GA signal over long distances. Quantitative analysis of endogenous GAs in xylem and phloem exudates further indicates that GA12 moves through the Plant Vascular System. Finally, we demonstrate that GA12 is functional in recipient tissues, supporting growth via the activation of the GA signalling cascade. Collectively, these results reveal the existence of long-range transport of endogenous GA12 in Plants that may have implications for the control of developmental phase transitions and the adaptation to adverse environments. Gibberellin is a major hormone in Plant growth. Mixing old-style grafting with modern molecular genetics in Arabidopsis shows that the GA12 precursor is the chemical form of gibberellin undergoing long-distance transport across Plant organs.
Enrico Scarpella - One of the best experts on this subject based on the ideXlab platform.
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pattern formation in the Vascular System of monocot and dicot Plant species
New Phytologist, 2004Co-Authors: Enrico Scarpella, Annemarie H MeijerAbstract:Contents Summary I. Introduction II. The Plant Vascular System III. Ontogeny of the Vascular tissues IV. Procambium development V. The organisation of the Vascular tissues VI. The regulation of longitudinal Vascular pattern formation VII. The regulation of radial Vascular pattern formation VIII. Genetic screens for Vascular development mutants IX. Genes involved in Vascular development identified through reverse genetics approaches X. Conclusions and perspectives Note added at the revision stage Acknowledgements References Summary Plant Vascular tissues are organised in continuous strands, the longitudinal and radial patterns of which are intimately linked to the signals that direct Plant architecture as a whole. Therefore, understanding the mechanisms underlying Vascular tissue patterning is expected to shed light on patterning events beyond those that organise the Vascular System, and thus represents a central issue in Plant developmental biology. A number of recent advances, reviewed here, are leading to a more precise definition of the signals that control the formation of Vascular tissues and their integration into a larger organismal context.
Catherine Bellini - One of the best experts on this subject based on the ideXlab platform.
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the Plant specific dof transcription factors family new players involved in Vascular System development and functioning in arabidopsis
Frontiers in Plant Science, 2013Co-Authors: Catherine BelliniAbstract:In higher Plants phloem and xylem are responsible for long-distance transport of water, nutrients, and signals that act Systemically at short or long-distance to coordinate developmental processes. The formation of the Plant Vascular System is a complex process that integrates signaling events and gene regulation at transcriptional and posttranscriptional levels. Thanks to transcriptomic and proteomic analysis we start to better understand the mechanisms underlying the formation and the functioning of the Vascular System. The role of the DNA-binding with one finger (Dof TFs), a group of Plant-specific transcription factors, recently emerged as part of the transcriptional regulatory networks acting on the formation and functioning of the Vascular tissues. More than half of the members of this TF family are expressed in the Vascular System. In addition some of them have been proposed to be mobile proteins, suggesting a possible role in the control of short- or long-distance signaling as well. This review summarizes the current knowledge on Dof TFs family in Arabidopsis with a special focus on their role in Vascular development and functioning.
Thomas Regnault - One of the best experts on this subject based on the ideXlab platform.
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Long-distance transport of endogenous gibberellins in Arabidopsis
Plant Signaling & Behavior, 2016Co-Authors: Thomas Regnault, Jean-michel Davière, Patrick AchardAbstract:Gibberellins (GAs) are phytohormones controlling major aspects of Plant growth and development. Although previous studies suggested the existence of a transport of GAs in Plants, the nature and properties associated with this transport were unknown. We recently showed through micrografting and biochemical approaches that the GA12 precursor is the chemical form of GA undergoing long-distance transport across Plant organs in Arabidopsis. Endogenous GA12 moves through the Plant Vascular System from production sites to recipient tissues, in which GA12 can be converted to bioactive forms to support growth via the activation of GA-dependent processes. GAs are also essential to promote seed germination; hence GA biosynthesis mutants do not germinate without exogenous GA treatment. Our results suggest that endogenous GAs are not (or not sufficiently) transmitted to the offspring to successfully complete the germination under permissive conditions.
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The gibberellin precursor GA_12 acts as a long-distance growth signal in Arabidopsis
Nature Plants, 2015Co-Authors: Thomas Regnault, Jean-michel Davière, Michael Wild, Lali Sakvarelidze-achard, Dimitri Heintz, Esther Carrera Bergua, Isabel Lopez Diaz, Fan Gong, Peter Hedden, Patrick AchardAbstract:Gibberellin is a major hormone in Plant growth. Mixing old-style grafting with modern molecular genetics in Arabidopsis shows that the GA_12 precursor is the chemical form of gibberellin undergoing long-distance transport across Plant organs. The gibberellin (GA) phytohormones play important roles in Plant growth and development, promoting seed germination, elongation growth and reproductive development^ 1 . Over the years, substantial progress has been made in understanding the regulation of GA signalling and metabolism, which ensures appropriate levels of GAs for growth and development^ 2 . Moreover, an additional level of regulation may reside in the transport of GAs from production sites to recipient tissues that require GAs for growth. Although there is considerable evidence suggesting the existence of short- and long-distance movement of GAs in Plants^ 3 – 8 , the nature and the biological properties of this transport are not yet understood. Here, we combine biochemical and conventional micrografting experiments in Arabidopsis thaliana to show that the GA precursor GA_12, although biologically inactive by itself, is the major mobile GA signal over long distances. Quantitative analysis of endogenous GAs in xylem and phloem exudates further indicates that GA_12 moves through the Plant Vascular System. Finally, we demonstrate that GA_12 is functional in recipient tissues, supporting growth via the activation of the GA signalling cascade. Collectively, these results reveal the existence of long-range transport of endogenous GA_12 in Plants that may have implications for the control of developmental phase transitions and the adaptation to adverse environments.
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The gibberellin precursor GA12 acts as a long-distance growth signal in Arabidopsis
Nature plants, 2015Co-Authors: Thomas Regnault, Jean-michel Davière, Michael Wild, Lali Sakvarelidze-achard, Dimitri Heintz, Fan Gong, Peter Hedden, Esther Carrera Bergua, Isabel Díaz, Patrick AchardAbstract:The gibberellin (GA) phytohormones play important roles in Plant growth and development, promoting seed germination, elongation growth and reproductive development1. Over the years, substantial progress has been made in understanding the regulation of GA signalling and metabolism, which ensures appropriate levels of GAs for growth and development2. Moreover, an additional level of regulation may reside in the transport of GAs from production sites to recipient tissues that require GAs for growth. Although there is considerable evidence suggesting the existence of short- and long-distance movement of GAs in Plants3–8, the nature and the biological properties of this transport are not yet understood. Here, we combine biochemical and conventional micrografting experiments in Arabidopsis thaliana to show that the GA precursor GA12, although biologically inactive by itself, is the major mobile GA signal over long distances. Quantitative analysis of endogenous GAs in xylem and phloem exudates further indicates that GA12 moves through the Plant Vascular System. Finally, we demonstrate that GA12 is functional in recipient tissues, supporting growth via the activation of the GA signalling cascade. Collectively, these results reveal the existence of long-range transport of endogenous GA12 in Plants that may have implications for the control of developmental phase transitions and the adaptation to adverse environments. Gibberellin is a major hormone in Plant growth. Mixing old-style grafting with modern molecular genetics in Arabidopsis shows that the GA12 precursor is the chemical form of gibberellin undergoing long-distance transport across Plant organs.