The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Tomomichi Fujita - One of the best experts on this subject based on the ideXlab platform.
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Metabolic Control of Gametophore Shoot Formation through Arginine in the Moss Physcomitrium patens
Cell reports, 2020Co-Authors: Kensuke Kawade, Tomomichi Fujita, Gorou Horiguchi, Yuu Hirose, Akira Oikawa, Masami Yokota Hirai, Kazuki Saito, Hirokazu TsukayaAbstract:Shoot formation is accompanied by active cell proliferation and expansion, requiring that metabolic state adapts to developmental control. Despite the importance of such metabolic reprogramming, it remains unclear how development and metabolism are integrated. Here, we show that disruption of ANGUSTIFOLIA3 orthologs (PpAN3s) compromises Gametophore shoot formation in the moss Physcomitrium patens due to defective cell proliferation and expansion. Trans-omics analysis reveals that the downstream activity of PpAN3 is linked to arginine metabolism. Elevating arginine level by chemical treatment leads to stunted Gametophores and causes Ppan3 mutant-like transcriptional changes in the wild-type plant. Furthermore, ectopic expression of AtAN3 from Arabidopsis thaliana ameliorates the defective arginine metabolism and promotes Gametophore formation in Ppan3 mutants. Together, these findings indicate that arginine metabolism is a key pathway associated with Gametophore formation and provide evolutionary insights into the establishment of the shoot system in land plants through the integration of developmental and metabolic processes.
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metabolic control of Gametophore shoot formation through arginine in the moss physcomitrella patens
2020Co-Authors: Kensuke Kawade, Tomomichi Fujita, Gorou Horiguchi, Yuu Hirose, Akira Oikawa, Masami Yokota Hirai, Kazuki Saito, Hirokazu TsukayaAbstract:Shoot formation is accompanied by active cell proliferation and expansion, which requires adaptation of the metabolic state to allow for developmental control. Despite the importance of such metabolic reprogramming, it remains unclear how development and metabolism are integrated. In this study, we showed that disruption of ANGUSTIFOLIA3 orthologs (PpAN3s) compromised Gametophore shoot formation in the moss Physcomitrella patens due to defective cell proliferation and expansion. Trans-omics analysis revealed that the downstream activity of PpAN3 is linked to arginine metabolism. Elevating arginine level by chemical treatment led to stunted Gametophores and caused Ppan3 mutant-like transcriptional changes in the wild-type plant. Furthermore, ectopic expression of AtAN3 from Arabidopsis thaliana ameliorated the defective arginine metabolism and promoted Gametophore formation in Ppan3 mutants. Together, these findings indicate that arginine metabolism is a key pathway associated with Gametophore formation and provide evolutionary insights into the establishment of the shoot system in land plants through the integration of developmental and metabolic processes.
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An Experimental System for Examining Phototropic Response of Gametophytic Shoots in the Moss Physcomitrella patens.
Methods in molecular biology (Clifton N.J.), 2019Co-Authors: Liang Bao, Kotaro T. Yamamoto, Tomomichi FujitaAbstract:Shoot phototropism benefits growth and metabolism in land plants by enabling them to position their photosynthetic organs in favorable light conditions. Nonvascular land plants, like the ancestors of modern mosses, are believed to have been among the first plants to occupy the land. To understand the evolutional history of shoot phototropism in land plants, we have established a system for experimentally studying phototropism in Gametophores of the moss Physcomitrella patens. Here we will describe the key points in our system, including obtaining etiolated Gametophores, the light sources used for inducing bending, and the methods for evaluation of phototropic responses.
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Hypergravity of 10g Changes Plant Growth, Anatomy, Chloroplast Size, and Photosynthesis in the Moss Physcomitrella patens
Microgravity Science and Technology, 2017Co-Authors: Kaori Takemura, Rina Watanabe, Ryuji Kameishi, Naoya Sakaguchi, Hiroyuki Kamachi, Atsushi Kume, Ichirou Karahara, Yuko T. Hanba, Tomomichi FujitaAbstract:The photosynthetic and anatomical responses of bryophytes to changes in gravity will provide crucial information for estimating how these plant traits evolved to adapt to changes in gravity in land plant history. We performed long-term hypergravity experiments at 10 g for 4 and 8 weeks using the moss Physcomitrella patens with two centrifuges equipped with lighting systems that enable long-term plant growth under hypergravity with irradiance. The aims of this study are (1) to quantify changes in the anatomy and morphology of P. patens , and (2) to analyze the post-effects of hypergravity on photosynthesis by P. patens in relation to these changes. We measured photosynthesis by P. patens for a population of Gametophores (e.g., canopy) in Petri dishes and plant culture boxes. Gametophore numbers increased by 9% for a canopy of P. patens , with 24–27% increases in chloroplast sizes (diameter and thickness) in leaf cells. In a canopy of P. patens , the area-based photosynthesis rate ( A _canopy) was increased by 57% at 10 g . The increase observed in A _canopy was associated with greater plant numbers and chloroplast sizes, both of which involved enhanced CO_2 diffusion from the atmosphere to chloroplasts in the canopies of P. patens . These results suggest that changes in gravity are important environmental stimuli to induce changes in plant growth and photosynthesis by P. patens , in which an alteration in chloroplast size is one of the key traits. We are now planning an ISS experiment to investigate the responses of P. patens to microgravity.
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Hypergravity of 10 g Changes Plant Growth, Anatomy, Chloroplast Size, and Photosynthesis in the Moss Physcomitrella patens
Microgravity Science and Technology, 2017Co-Authors: Kaori Takemura, Rina Watanabe, Ryuji Kameishi, Naoya Sakaguchi, Hiroyuki Kamachi, Atsushi Kume, Ichirou Karahara, Yuko T. Hanba, Tomomichi FujitaAbstract:The photosynthetic and anatomical responses of bryophytes to changes in gravity will provide crucial information for estimating how these plant traits evolved to adapt to changes in gravity in land plant history. We performed long-term hypergravity experiments at 10g for 4 and 8 weeks using the moss Physcomitrella patens with two centrifuges equipped with lighting systems that enable long-term plant growth under hypergravity with irradiance. The aims of this study are (1) to quantify changes in the anatomy and morphology of P. patens, and (2) to analyze the post-effects of hypergravity on photosynthesis by P. patens in relation to these changes. We measured photosynthesis by P. patens for a population of Gametophores (e.g., canopy) in Petri dishes and plant culture boxes. Gametophore numbers increased by 9% for a canopy of P. patens, with 24–27% increases in chloroplast sizes (diameter and thickness) in leaf cells. In a canopy of P. patens, the area-based photosynthesis rate (A canopy) was increased by 57% at 10g. The increase observed in A canopy was associated with greater plant numbers and chloroplast sizes, both of which involved enhanced CO2 diffusion from the atmosphere to chloroplasts in the canopies of P. patens. These results suggest that changes in gravity are important environmental stimuli to induce changes in plant growth and photosynthesis by P. patens, in which an alteration in chloroplast size is one of the key traits. We are now planning an ISS experiment to investigate the responses of P. patens to microgravity.
Mitsuyasu Hasebe - One of the best experts on this subject based on the ideXlab platform.
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two angustifolia genes regulate Gametophore and sporophyte development in physcomitrella patens
Plant Journal, 2020Co-Authors: Yoshikazu Hashida, Mitsuyasu Hasebe, Katsuaki Takechi, Tomomi Abiru, Noriyuki Yabe, Hiroaki Nagase, Koro Hattori, Susumu Takio, Yoshikatsu Sato, Hirokazu TsukayaAbstract:In Arabidopsis thaliana the ANGUSTIFOLIA (AN) gene regulates the width of leaves by controlling the diffuse growth of leaf cells in the medio-lateral direction. In the genome of the moss Physcomitrella patens, we found two normal ANs (PpAN1-1 and 1-2). Both PpAN1 genes complemented the A. thaliana an-1 mutant phenotypes. An analysis of spatiotemporal promoter activity of each PpAN1 gene, using transgenic lines that contained each PpAN1-promoter- uidA (GUS) gene, showed that both promoters are mainly active in the stems of haploid Gametophores and in the middle to basal region of the young sporophyte that develops into the seta and foot. Analyses of the knockout lines for PpAN1-1 and PpAN1-2 genes suggested that these genes have partially redundant functions and regulate Gametophore height by controlling diffuse cell growth in Gametophore stems. In addition, the seta and foot were shorter and thicker in diploid sporophytes, suggesting that cell elongation was reduced in the longitudinal direction, whereas no defects were detected in tip-growing protonemata. These results indicate that both PpAN1 genes in P. patens function in diffuse growth of the haploid and diploid generations but not in tip growth. To visualize microtubule distribution in Gametophore cells of P. patens, transformed lines expressing P. patens α-tubulin fused to sGFP were generated. Contrary to expectations, the orientation of microtubules in the tips of Gametophores in the PpAN1-1/1-2 double-knockout lines was unchanged. The relationships among diffuse cell growth, cortical microtubules and AN proteins are discussed.
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Antheridial development in the moss physcomitrella patens: Implications for understanding stem cells in mosses
Philosophical transactions of the Royal Society of London. Series B Biological sciences, 2017Co-Authors: Rumiko Kofuji, Yasushi Yagita, Takashi Murata, Mitsuyasu HasebeAbstract:Stem cells self-renew and produce precursor cells that differentiate to become specialized cell types. Land plants generate several types of stem cells that give rise to most organs of the plant body and whose characters determine the body organization. The moss Physcomitrella patens forms eight types of stem cells throughout its life cycle. Under gametangium-inducing conditions, multiple antheridium apical stem cells are formed at the tip of the Gametophore and each antheridium apical stem cell divides to form an antheridium. We found that the Gametophore apical stem cell, which typically forms leaf and stem tissues, changes to become a new type of stem cell, which we term the antheridium initial stem cell. This antheridium initial stem cell produces multiple antheridium apical stem cells, resulting in a cluster of antheridia at the tip of Gametophore. This is the first report of a land plant stem cell directly producing another type of stem cell during normal development. Notably, the antheridium apical stem cells are distally produced from the antheridium initial stem cell, similar to the root cap stem cells of vascular plants, suggesting the use of similar molecular mechanisms and a possible evolutionary relationship.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'.
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Spatial expression patterns of dually induced NGG and NmRFP1.
2013Co-Authors: Minoru Kubo, Yuji Hiwatashi, Yoshikatsu Sato, Ralf Reski, Akihiro Imai, Tomoaki Nishiyama, Masaki Ishikawa, Tetsuya Kurata, Mitsuyasu HasebeAbstract:Fluorescence images of protonemata and a Gametophore leaf of the GX6-NGG#63/LGZ2-NmRFP1#11 line. They were immersed in water containing 1 µM β-estradiol for 24 h before microscopy. Fluorescence images of NGG and chlorophyll autofluorescence (top row), NGG (second row), NmRFP1 (third row), and a merged image of NGG and NmRFP1 (bottom row) are indicated. Each picture is at the same magnification. Bar = 200 µm.
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ap2 type transcription factors determine stem cell identity in the moss physcomitrella patens
Development, 2012Co-Authors: Tsuyoshi Aoyama, Yuji Hiwatashi, Mikao Shigyo, Rumiko Kofuji, Minoru Kubo, Motomi Ito, Mitsuyasu HasebeAbstract:Stem cells are formed at particular times and positions during the development of multicellular organisms. Whereas flowering plants form stem cells only in the sporophyte generation, non-seed plants form stem cells in both the sporophyte and gametophyte generations. Although the molecular mechanisms underlying stem cell formation in the sporophyte generation have been extensively studied, only a few transcription factors involved in the regulation of gametophyte stem cell formation have been reported. The moss Physcomitrella patens forms a hypha-like body (protonema) and a shoot-like body (Gametophore) from a protonema apical cell and a Gametophore apical cell, respectively. These apical cells have stem cell characteristics and are formed as side branches of differentiated protonema cells. Here, we show that four AP2-type transcription factors orthologous to Arabidopsis thaliana AINTEGUMENTA, PLETHORA and BABY BOOM (APB) are indispensable for the formation of Gametophore apical cells from protonema cells. Quadruple disruption of all APB genes blocked Gametophore formation, even in the presence of cytokinin, which enhances Gametophore apical cell formation in the wild type. All APB genes were expressed in emerging Gametophore apical cells, but not in protonema apical cells. Heat-shock induction of an APB4 transgene driven by a heat-shock promoter increased the number of Gametophores. Expression of all APB genes was induced by auxin but not by cytokinin. Thus, the APB genes function synergistically with cytokinin signaling to determine the identity of the two types of stem cells.
Celine Charon - One of the best experts on this subject based on the ideXlab platform.
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The function of the RNA-binding protein TEL1 in moss reveals ancient regulatory mechanisms of shoot development
Plant Molecular Biology, 2012Co-Authors: Julien Vivancos, Fabien Nogué, Florence Charlot, Lara Spinner, Christelle Mazubert, Nicolas Paquet, Vincent Thareau, Michel Dron, Celine CharonAbstract:The shoot represents the basic body plan in land plants. It consists of a repeated structure composed of stems and leaves. Whereas vascular plants generate a shoot in their diploid phase, non-vascular plants such as mosses form a shoot (called the Gametophore) in their haploid generation. The evolution of regulatory mechanisms or genetic networks used in the development of these two kinds of shoots is unclear. TERMINAL EAR1 - like genes have been involved in diploid shoot development in vascular plants. Here, we show that disruption of PpTEL1 from the moss Physcomitrella patens , causes reduced protonema growth and Gametophore initiation, as well as defects in Gametophore development. Leafy shoots formed on Δ TEL1 mutants exhibit shorter stems with more leaves per shoot, suggesting an accelerated leaf initiation (shortened plastochron), a phenotype shared with the Poaceae vascular plants TE1 and PLA2/LHD2 mutants. Moreover, the positive correlation between plastochron length and leaf size observed in Δ TEL1 mutants suggests a conserved compensatory mechanism correlating leaf growth and leaf initiation rate that would minimize overall changes in plant biomass. The RNA-binding protein encoded by PpTEL1 contains two N-terminus RNA-recognition motifs, and a third C-terminus non-canonical RRM, specific to TEL proteins. Removal of the PpTEL1 C-terminus (including this third RRM) or only 16–18 amino acids within it seriously impairs PpTEL1 function, suggesting a critical role for this third RRM. These results show a conserved function of the RNA-binding PpTEL1 protein in the regulation of shoot development, from early ancestors to vascular plants, that depends on the third TEL-specific RRM.
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The function of the RNA-binding protein TEL1 in moss reveals ancient regulatory mechanisms of shoot development
Plant Molecular Biology, 2012Co-Authors: Julien Vivancos, Fabien Nogué, Florence Charlot, Lara Spinner, Christelle Mazubert, Nicolas Paquet, Vincent Thareau, Michel Dron, Celine CharonAbstract:The shoot represents the basic body plan in land plants. It consists of a repeated structure composed of stems and leaves. Whereas vascular plants generate a shoot in their diploid phase, non-vascular plants such as mosses form a shoot (called the Gametophore) in their haploid generation. The evolution of regulatory mechanisms or genetic networks used in the development of these two kinds of shoots is unclear. TERMINAL EAR1-like genes have been involved in diploid shoot development in vascular plants. Here, we show that disruption of PpTEL1 from the moss Physcomitrella patens, causes reduced protonema growth and Gametophore initiation, as well as defects in Gametophore development. Leafy shoots formed on Delta TEL1 mutants exhibit shorter stems with more leaves per shoot, suggesting an accelerated leaf initiation (shortened plastochron), a phenotype shared with the Poaceae vascular plants TE1 and PLA2/LHD2 mutants. Moreover, the positive correlation between plastochron length and leaf size observed in DTEL1 mutants suggests a conserved compensatory mechanism correlating leaf growth and leaf initiation rate that would minimize overall changes in plant biomass. The RNA-binding protein encoded by PpTEL1 contains two N-terminus RNA-recognition motifs, and a third C-terminus non-canonical RRM, specific to TEL proteins. Removal of the PpTEL1 C-terminus (including this third RRM) or only 16-18 amino acids within it seriously impairs PpTEL1 function, suggesting a critical role for this third RRM. These results show a conserved function of the RNA-binding PpTEL1 protein in the regulation of shoot development, from early ancestors to vascular plants, that depends on the third TEL-specific RRM.
Fabien Nogué - One of the best experts on this subject based on the ideXlab platform.
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SEC6 exocyst subunit contributes to multiple steps of growth and development of Physcomitrella (Physcomitrium patens).
The Plant journal : for cell and molecular biology, 2021Co-Authors: Lucie Brejšková, Fabien Nogué, Florence Charlot, Michal Hála, Anamika Rawat, Hana Soukupová, Fatima Cvrčková, Samuel Haluška, Viktor ŽárskýAbstract:Spatially directed cell division and expansion is important for plant growth and morphogenesis, and relies on the cooperation between the cytoskeleton and secretory pathway. The phylogenetically conserved octameric complex exocyst mediates exocytotic vesicle tethering at the plasma membrane. Unlike other exocyst subunits of land plants, the core exocyst subunit SEC6 exists as a single paralog in Physcomitrium patens and Arabidopsis thaliana genomes. Arabidopsis SEC6 (AtSEC6) loss-of-function (LOF) mutation causes male gametophytic lethality. Our attempts to inactivate the P. patens SEC6 gene (PpSEC6) using targeted gene replacement produced two independent partial LOF ("weak allele") mutants via the PpSEC6 gene locus perturbation. These mutants exhibited the same pleiotropic developmental defects: protonema with dominant chloronema stage, diminished caulonemal filament elongation rate, and post-initiation Gametophore development failure. Mutant Gametophore buds, mostly initiated from chloronema cells, exhibited disordered cell file organization and cross-wall perforations, resulting in arrested development at the 8 -10 cell stage. Complementation of both sec6 moss mutant lines by both PpSEC6 and AtSEC6 cDNA rescued Gametophore development, including sexual organ differentiation. However, regular sporophyte formation and viable spore production were recovered only by the expression of PpSEC6, whereas the AtSEC6 complementants were only exceptionally fertile, indicating moss-specific SEC6 functions.
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The function of the RNA-binding protein TEL1 in moss reveals ancient regulatory mechanisms of shoot development
Plant Molecular Biology, 2012Co-Authors: Julien Vivancos, Fabien Nogué, Florence Charlot, Lara Spinner, Christelle Mazubert, Nicolas Paquet, Vincent Thareau, Michel Dron, Celine CharonAbstract:The shoot represents the basic body plan in land plants. It consists of a repeated structure composed of stems and leaves. Whereas vascular plants generate a shoot in their diploid phase, non-vascular plants such as mosses form a shoot (called the Gametophore) in their haploid generation. The evolution of regulatory mechanisms or genetic networks used in the development of these two kinds of shoots is unclear. TERMINAL EAR1 - like genes have been involved in diploid shoot development in vascular plants. Here, we show that disruption of PpTEL1 from the moss Physcomitrella patens , causes reduced protonema growth and Gametophore initiation, as well as defects in Gametophore development. Leafy shoots formed on Δ TEL1 mutants exhibit shorter stems with more leaves per shoot, suggesting an accelerated leaf initiation (shortened plastochron), a phenotype shared with the Poaceae vascular plants TE1 and PLA2/LHD2 mutants. Moreover, the positive correlation between plastochron length and leaf size observed in Δ TEL1 mutants suggests a conserved compensatory mechanism correlating leaf growth and leaf initiation rate that would minimize overall changes in plant biomass. The RNA-binding protein encoded by PpTEL1 contains two N-terminus RNA-recognition motifs, and a third C-terminus non-canonical RRM, specific to TEL proteins. Removal of the PpTEL1 C-terminus (including this third RRM) or only 16–18 amino acids within it seriously impairs PpTEL1 function, suggesting a critical role for this third RRM. These results show a conserved function of the RNA-binding PpTEL1 protein in the regulation of shoot development, from early ancestors to vascular plants, that depends on the third TEL-specific RRM.
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The function of the RNA-binding protein TEL1 in moss reveals ancient regulatory mechanisms of shoot development
Plant Molecular Biology, 2012Co-Authors: Julien Vivancos, Fabien Nogué, Florence Charlot, Lara Spinner, Christelle Mazubert, Nicolas Paquet, Vincent Thareau, Michel Dron, Celine CharonAbstract:The shoot represents the basic body plan in land plants. It consists of a repeated structure composed of stems and leaves. Whereas vascular plants generate a shoot in their diploid phase, non-vascular plants such as mosses form a shoot (called the Gametophore) in their haploid generation. The evolution of regulatory mechanisms or genetic networks used in the development of these two kinds of shoots is unclear. TERMINAL EAR1-like genes have been involved in diploid shoot development in vascular plants. Here, we show that disruption of PpTEL1 from the moss Physcomitrella patens, causes reduced protonema growth and Gametophore initiation, as well as defects in Gametophore development. Leafy shoots formed on Delta TEL1 mutants exhibit shorter stems with more leaves per shoot, suggesting an accelerated leaf initiation (shortened plastochron), a phenotype shared with the Poaceae vascular plants TE1 and PLA2/LHD2 mutants. Moreover, the positive correlation between plastochron length and leaf size observed in DTEL1 mutants suggests a conserved compensatory mechanism correlating leaf growth and leaf initiation rate that would minimize overall changes in plant biomass. The RNA-binding protein encoded by PpTEL1 contains two N-terminus RNA-recognition motifs, and a third C-terminus non-canonical RRM, specific to TEL proteins. Removal of the PpTEL1 C-terminus (including this third RRM) or only 16-18 amino acids within it seriously impairs PpTEL1 function, suggesting a critical role for this third RRM. These results show a conserved function of the RNA-binding PpTEL1 protein in the regulation of shoot development, from early ancestors to vascular plants, that depends on the third TEL-specific RRM.
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Water Transport by Aquaporins in the Extant Plant Physcomitrella patens
Plant physiology, 2008Co-Authors: David Lienard, Gaëlle Durambur, Marie-christine Kiefer-meyer, Fabien Nogué, Laurence Menu-bouaouiche, Florence Charlot, Véronique Gomord, Jean-paul LassallesAbstract:Although aquaporins (AQPs) have been shown to increase membrane water permeability in many cell types, the physiological role of this increase was not always obvious. In this report, we provide evidence that in the leafy stage of development (Gametophore) of the moss Physcomitrella patens, AQPs help to replenish more rapidly the cell water that is lost by transpiration, at least if some water is in the direct vicinity of the moss plant. Three AQP genes were cloned in P. patens: PIP2;1, PIP2;2, and PIP2;3. The water permeability of the membrane was measured in protoplasts from leaves and protonema. A significant decrease was measured in protoplasts from leaves and protonema of PIP2;1 or PIP2;2 knockouts but not the PIP2;3 knockout. No phenotype was observed when knockout plants were grown in closed petri dishes with ample water supply. Gametophores isolated from the wild type and the pip2;3 mutant were not sensitive to moderate water stress, but pip2;1 or pip2;2 Gametophores expressed a water stress phenotype. The knockout mutant leaves were more bent and twisted, apparently suffering from an important loss of cellular water. We propose a model to explain how the AQPs PIP2;1 and PIP2;2 delay leaf dessication in a drying atmosphere. We suggest that in ancestral land plants, some 400 million years ago, APQs were already used to facilitate the absorption of water.
Florence Charlot - One of the best experts on this subject based on the ideXlab platform.
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SEC6 exocyst subunit contributes to multiple steps of growth and development of Physcomitrella (Physcomitrium patens).
The Plant journal : for cell and molecular biology, 2021Co-Authors: Lucie Brejšková, Fabien Nogué, Florence Charlot, Michal Hála, Anamika Rawat, Hana Soukupová, Fatima Cvrčková, Samuel Haluška, Viktor ŽárskýAbstract:Spatially directed cell division and expansion is important for plant growth and morphogenesis, and relies on the cooperation between the cytoskeleton and secretory pathway. The phylogenetically conserved octameric complex exocyst mediates exocytotic vesicle tethering at the plasma membrane. Unlike other exocyst subunits of land plants, the core exocyst subunit SEC6 exists as a single paralog in Physcomitrium patens and Arabidopsis thaliana genomes. Arabidopsis SEC6 (AtSEC6) loss-of-function (LOF) mutation causes male gametophytic lethality. Our attempts to inactivate the P. patens SEC6 gene (PpSEC6) using targeted gene replacement produced two independent partial LOF ("weak allele") mutants via the PpSEC6 gene locus perturbation. These mutants exhibited the same pleiotropic developmental defects: protonema with dominant chloronema stage, diminished caulonemal filament elongation rate, and post-initiation Gametophore development failure. Mutant Gametophore buds, mostly initiated from chloronema cells, exhibited disordered cell file organization and cross-wall perforations, resulting in arrested development at the 8 -10 cell stage. Complementation of both sec6 moss mutant lines by both PpSEC6 and AtSEC6 cDNA rescued Gametophore development, including sexual organ differentiation. However, regular sporophyte formation and viable spore production were recovered only by the expression of PpSEC6, whereas the AtSEC6 complementants were only exceptionally fertile, indicating moss-specific SEC6 functions.
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The function of the RNA-binding protein TEL1 in moss reveals ancient regulatory mechanisms of shoot development
Plant Molecular Biology, 2012Co-Authors: Julien Vivancos, Fabien Nogué, Florence Charlot, Lara Spinner, Christelle Mazubert, Nicolas Paquet, Vincent Thareau, Michel Dron, Celine CharonAbstract:The shoot represents the basic body plan in land plants. It consists of a repeated structure composed of stems and leaves. Whereas vascular plants generate a shoot in their diploid phase, non-vascular plants such as mosses form a shoot (called the Gametophore) in their haploid generation. The evolution of regulatory mechanisms or genetic networks used in the development of these two kinds of shoots is unclear. TERMINAL EAR1 - like genes have been involved in diploid shoot development in vascular plants. Here, we show that disruption of PpTEL1 from the moss Physcomitrella patens , causes reduced protonema growth and Gametophore initiation, as well as defects in Gametophore development. Leafy shoots formed on Δ TEL1 mutants exhibit shorter stems with more leaves per shoot, suggesting an accelerated leaf initiation (shortened plastochron), a phenotype shared with the Poaceae vascular plants TE1 and PLA2/LHD2 mutants. Moreover, the positive correlation between plastochron length and leaf size observed in Δ TEL1 mutants suggests a conserved compensatory mechanism correlating leaf growth and leaf initiation rate that would minimize overall changes in plant biomass. The RNA-binding protein encoded by PpTEL1 contains two N-terminus RNA-recognition motifs, and a third C-terminus non-canonical RRM, specific to TEL proteins. Removal of the PpTEL1 C-terminus (including this third RRM) or only 16–18 amino acids within it seriously impairs PpTEL1 function, suggesting a critical role for this third RRM. These results show a conserved function of the RNA-binding PpTEL1 protein in the regulation of shoot development, from early ancestors to vascular plants, that depends on the third TEL-specific RRM.
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The function of the RNA-binding protein TEL1 in moss reveals ancient regulatory mechanisms of shoot development
Plant Molecular Biology, 2012Co-Authors: Julien Vivancos, Fabien Nogué, Florence Charlot, Lara Spinner, Christelle Mazubert, Nicolas Paquet, Vincent Thareau, Michel Dron, Celine CharonAbstract:The shoot represents the basic body plan in land plants. It consists of a repeated structure composed of stems and leaves. Whereas vascular plants generate a shoot in their diploid phase, non-vascular plants such as mosses form a shoot (called the Gametophore) in their haploid generation. The evolution of regulatory mechanisms or genetic networks used in the development of these two kinds of shoots is unclear. TERMINAL EAR1-like genes have been involved in diploid shoot development in vascular plants. Here, we show that disruption of PpTEL1 from the moss Physcomitrella patens, causes reduced protonema growth and Gametophore initiation, as well as defects in Gametophore development. Leafy shoots formed on Delta TEL1 mutants exhibit shorter stems with more leaves per shoot, suggesting an accelerated leaf initiation (shortened plastochron), a phenotype shared with the Poaceae vascular plants TE1 and PLA2/LHD2 mutants. Moreover, the positive correlation between plastochron length and leaf size observed in DTEL1 mutants suggests a conserved compensatory mechanism correlating leaf growth and leaf initiation rate that would minimize overall changes in plant biomass. The RNA-binding protein encoded by PpTEL1 contains two N-terminus RNA-recognition motifs, and a third C-terminus non-canonical RRM, specific to TEL proteins. Removal of the PpTEL1 C-terminus (including this third RRM) or only 16-18 amino acids within it seriously impairs PpTEL1 function, suggesting a critical role for this third RRM. These results show a conserved function of the RNA-binding PpTEL1 protein in the regulation of shoot development, from early ancestors to vascular plants, that depends on the third TEL-specific RRM.
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Water Transport by Aquaporins in the Extant Plant Physcomitrella patens
Plant physiology, 2008Co-Authors: David Lienard, Gaëlle Durambur, Marie-christine Kiefer-meyer, Fabien Nogué, Laurence Menu-bouaouiche, Florence Charlot, Véronique Gomord, Jean-paul LassallesAbstract:Although aquaporins (AQPs) have been shown to increase membrane water permeability in many cell types, the physiological role of this increase was not always obvious. In this report, we provide evidence that in the leafy stage of development (Gametophore) of the moss Physcomitrella patens, AQPs help to replenish more rapidly the cell water that is lost by transpiration, at least if some water is in the direct vicinity of the moss plant. Three AQP genes were cloned in P. patens: PIP2;1, PIP2;2, and PIP2;3. The water permeability of the membrane was measured in protoplasts from leaves and protonema. A significant decrease was measured in protoplasts from leaves and protonema of PIP2;1 or PIP2;2 knockouts but not the PIP2;3 knockout. No phenotype was observed when knockout plants were grown in closed petri dishes with ample water supply. Gametophores isolated from the wild type and the pip2;3 mutant were not sensitive to moderate water stress, but pip2;1 or pip2;2 Gametophores expressed a water stress phenotype. The knockout mutant leaves were more bent and twisted, apparently suffering from an important loss of cellular water. We propose a model to explain how the AQPs PIP2;1 and PIP2;2 delay leaf dessication in a drying atmosphere. We suggest that in ancestral land plants, some 400 million years ago, APQs were already used to facilitate the absorption of water.
