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Kumar A, Krausko M, Jásik J. SYNAPTOTAGMIN 4 is expressed mainly in the phloem and participates in abiotic stress tolerance in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2024; 15:1363555. [PMID: 39011301 PMCID: PMC11246894 DOI: 10.3389/fpls.2024.1363555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Accepted: 06/04/2024] [Indexed: 07/17/2024]
Abstract
Plant synaptotagmins structurally resemble animal synaptotagmins and extended-synaptotagmins. Animal synaptotagmins are well-characterized calcium sensors in membrane trafficking, and extended-synaptotagmins mediate lipid transfer at the endoplasmic reticulum-plasma membrane contact sites. Here, we characterize SYNAPTOTAGMIN 4 (SYT4), which belongs to the six-member family in Arabidopsis. Fluorometric GUS assay showed that the SYT4 promoter was strongest in roots and the least active in rosettes and cauline leaves, which was confirmed by qPCR. In seedlings, promoter activity was influenced by several factors, such as plant growth regulators, mannitol, sucrose, polyethylene glycol and cold. GUS histochemistry revealed SYT4 promoter activity in the phloem of all organs and even almost exclusively in sieve element precursors and differentiating sieve elements. Accordingly, the SYT-GFP fusion protein also accumulated in these cells with maximal abundance in sieve element precursors. The protein formed a network in the cytoplasm, but during sieve tube differentiation, it deposited at the cell periphery and disappeared from mature tubes. Using photoconvertible fluorescence technology, we showed that a high abundance of SYT4 protein in meristematic protophloem cells was due to its extensive synthesis. SYT4 protein synthesis was interrupted in differentiating sieve elements, but protein degradation was also reduced. In addition to phloem, the fusion protein was detected in shoot and root stem cell niche as early as the late heart stage of the embryo. We isolated and molecularly and biologically characterized five syt4 T-DNA insertion alleles and subjected them to phenotype analysis. The allele with the C2B domain interrupted by an T-DNA insertion exhibits increased sensitivity to factors such as auxins, osmotics, salicylic acid, sodium chloride, and the absence of sucrose in the root growth test.
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Affiliation(s)
- Ajay Kumar
- Department of Experimental Plant Biology, Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Miroslav Krausko
- Department of Experimental Plant Biology, Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Ján Jásik
- Department of Experimental Plant Biology, Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Bratislava, Slovakia
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2
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Lv M, Dai Y, Xie L, Guo J, Liao Z, Shang W, Zhao X, Hong J, Zhang HM. Volume electron microscopy reconstruction uncovers a physical barrier that limits virus to phloem. THE NEW PHYTOLOGIST 2024; 241:343-362. [PMID: 37858933 DOI: 10.1111/nph.19319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 09/20/2023] [Indexed: 10/21/2023]
Abstract
Most plant reoviruses are phloem-limited, but the mechanism has remained unknown for more than half a century. Southern rice black-streaked dwarf virus (Fijivirus, Reoviridae) causes phloem-derived tumors, where its virions, genomes, and proteins accumulate, and it was used as a model to explore how its host plant limits the virus within its phloem. High-throughput volume electron microscopy revealed that only sieve plate pores and flexible gateways rather than plasmodesmata had a sufficiently large size exclusion limit (SEL) to accommodate virions and potentially serve as pathways of virion movement. The large SEL gateways were enriched within the proliferated sieve element (SE) layers of tumors. The lack of such connections out of the SE-enriched regions of tumors defined a size-dependent physical barrier to high flux transportation of virions. A working model is proposed to demonstrate the mechanism underlying limitation of virus within phloem.
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Affiliation(s)
- Mingfang Lv
- Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Yuanxing Dai
- Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, China
| | - Li Xie
- Analysis Center of Agrobiology and Environmental Sciences, Zhejiang University, Hangzhou, 310058, China
- College of Agricultural Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Jiansheng Guo
- Department of Biophysics, Zhejiang University School of Medicine and Center of Cryo Electron Microscopy, Zhejiang University, Hangzhou, 310058, China
| | - Zhenfeng Liao
- Public Lab, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Weina Shang
- Analysis Center of Agrobiology and Environmental Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Xiaohuan Zhao
- Analysis Center of Agrobiology and Environmental Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Jian Hong
- Analysis Center of Agrobiology and Environmental Sciences, Zhejiang University, Hangzhou, 310058, China
- College of Agricultural Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Heng-Mu Zhang
- Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, China
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3
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Sun Y, Yang B, De Rybel B. Hormonal control of the molecular networks guiding vascular tissue development in the primary root meristem of Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:6964-6974. [PMID: 37343122 PMCID: PMC7615341 DOI: 10.1093/jxb/erad232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 06/16/2023] [Indexed: 06/23/2023]
Abstract
Vascular tissues serve a dual function in plants, both providing physical support and controlling the transport of nutrients, water, hormones, and other small signaling molecules. Xylem tissues transport water from root to shoot; phloem tissues transfer photosynthates from shoot to root; while divisions of the (pro)cambium increase the number of xylem and phloem cells. Although vascular development constitutes a continuous process from primary growth in the early embryo and meristem regions to secondary growth in the mature plant organs, it can be artificially separated into distinct processes including cell type specification, proliferation, patterning, and differentiation. In this review, we focus on how hormonal signals orchestrate the molecular regulation of vascular development in the Arabidopsis primary root meristem. Although auxin and cytokinin have taken center stage in this aspect since their discovery, other hormones including brassinosteroids, abscisic acid, and jasmonic acid also take leading roles during vascular development. All these hormonal cues synergistically or antagonistically participate in the development of vascular tissues, forming a complex hormonal control network.
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Affiliation(s)
- Yanbiao Sun
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium
- VIB Centre for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Baojun Yang
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium
- VIB Centre for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Bert De Rybel
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium
- VIB Centre for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
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Kalmbach L, Bourdon M, Belevich I, Safran J, Lemaire A, Heo JO, Otero S, Blob B, Pelloux J, Jokitalo E, Helariutta Y. Putative pectate lyase PLL12 and callose deposition through polar CALS7 are necessary for long-distance phloem transport in Arabidopsis. Curr Biol 2023; 33:926-939.e9. [PMID: 36805125 DOI: 10.1016/j.cub.2023.01.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 11/12/2022] [Accepted: 01/19/2023] [Indexed: 02/18/2023]
Abstract
In plants, the phloem distributes photosynthetic products for metabolism and storage over long distances. It relies on specialized cells, the sieve elements, which are enucleated and interconnected through large so-called sieve pores in their adjoining cell walls. Reverse genetics identified PECTATE LYASE-LIKE 12 (PLL12) as critical for plant growth and development. Using genetic complementations, we established that PLL12 is required exclusively late during sieve element differentiation. Structural homology modeling, enzyme inactivation, and overexpression suggest a vital role for PLL12 in sieve-element-specific pectin remodeling. While short distance symplastic diffusion is unaffected, the pll12 mutant is unable to accommodate sustained plant development due to an incapacity to accommodate increasing hydraulic demands on phloem long-distance transport as the plant grows-a defect that is aggravated when combined with another sieve-element-specific mutant callose synthase 7 (cals7). Establishing CALS7 as a specific sieve pore marker, we investigated the subcellular dynamics of callose deposition in the developing sieve plate. Using fluorescent CALS7 then allowed identifying structural defects in pll12 sieve pores that are moderate at the cellular level but become physiologically relevant due to the serial arrangement of sieve elements in the sieve tube. Overall, pectin degradation through PLL12 appears subtle in quantitative terms. We therefore speculate that PLL12 may act as a regulator to locally remove homogalacturonan, thus potentially enabling further extracellular enzymes to access and modify the cell wall during sieve pore maturation.
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Affiliation(s)
- Lothar Kalmbach
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK.
| | - Matthieu Bourdon
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Ilya Belevich
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Josip Safran
- UMR INRAE 1158 BioEcoAgro, BIOPI Biologie des Plantes et Innovation, Université de Picardie, 33 Rue St Leu, 80039 Amiens, France
| | - Adrien Lemaire
- UMR INRAE 1158 BioEcoAgro, BIOPI Biologie des Plantes et Innovation, Université de Picardie, 33 Rue St Leu, 80039 Amiens, France
| | - Jung-Ok Heo
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK; Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Sofia Otero
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Bernhard Blob
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Jérôme Pelloux
- UMR INRAE 1158 BioEcoAgro, BIOPI Biologie des Plantes et Innovation, Université de Picardie, 33 Rue St Leu, 80039 Amiens, France
| | - Eija Jokitalo
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Ykä Helariutta
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK; Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland.
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Sidorenko A, Omelyanchuk N, Zemlyanskaya E. Molecular mechanisms of vascular tissue patterning in Arabidopsis thaliana L. roots. Vavilovskii Zhurnal Genet Selektsii 2022; 26:721-732. [PMID: 36694717 PMCID: PMC9834716 DOI: 10.18699/vjgb-22-88] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 11/08/2022] [Accepted: 11/10/2022] [Indexed: 01/06/2023] Open
Abstract
A vascular system in plants is a product of aromorphosis that enabled them to colonize land because it delivers water, mineral and organic compounds to plant organs and provides effective communications between organs and mechanical support. Vascular system development is a common object of fundamental research in plant development biology. In the model plant Arabidopsis thaliana, early stages of vascular tissue formation in the root are a bright example of the self-organization of a bisymmetric (having two planes of symmetry) pattern of hormone distribution, which determines vascular cell fates. In the root, vascular tissue development comprises four stages: (1) specification of progenitor cells for the provascular meristem in early embryonic stages, (2) the growth and patterning of the embryo provascular meristem, (3) postembryonic maintenance of the cell identity in the vascular tissue initials within the root apical meristem, and (4) differentiation of their descendants. Although the anatomical details of A. thaliana root vasculature development have long been known and described in detail, our knowledge of the underlying molecular and genetic mechanisms remains limited. In recent years, several important advances have been made, shedding light on the regulation of the earliest events in provascular cells specification. In this review, we summarize the latest data on the molecular and genetic mechanisms of vascular tissue patterning in A. thaliana root. The first part of the review describes the root vasculature ontogeny, and the second reconstructs the sequence of regulatory events that underlie this histogenesis and determine the development of the progenitors of the vascular initials in the embryo and organization of vascular initials in the seedling root.
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Affiliation(s)
- A.D. Sidorenko
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, RussiaNovosibirsk State University, Novosibirsk, Russia
| | - N.A. Omelyanchuk
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - E.V. Zemlyanskaya
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, RussiaNovosibirsk State University, Novosibirsk, Russia
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6
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Koh SWH, Diaz-Ardila HN, Bascom CS, Berenguer E, Ingram G, Estelle M, Hardtke CS. Heterologous expression of a lycophyte protein enhances angiosperm seedling vigor. Development 2022; 149:dev200917. [PMID: 36196593 PMCID: PMC10655917 DOI: 10.1242/dev.200917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 09/26/2022] [Indexed: 03/15/2023]
Abstract
Seedling vigor is a key agronomic trait that determines juvenile plant performance. Angiosperm seeds develop inside fruits and are connected to the mother plant through vascular tissues. Their formation requires plant-specific genes, such as BREVIS RADIX (BRX) in Arabidopsis thaliana roots. BRX family proteins are found throughout the euphyllophytes but also occur in non-vascular bryophytes and non-seed lycophytes. They consist of four conserved domains, including the tandem BRX domains. We found that bryophyte or lycophyte BRX homologs can only partially substitute for Arabidopsis BRX (AtBRX) because they miss key features in the linker between the BRX domains. Intriguingly, however, expression of a BRX homolog from the lycophyte Selaginella moellendorffii (SmBRX) in an A. thaliana wild-type background confers robustly enhanced root growth vigor that persists throughout the life cycle. This effect can be traced to a substantial increase in seed and embryo size, is associated with enhanced vascular tissue proliferation, and can be reproduced with a modified, SmBRX-like variant of AtBRX. Our results thus suggest that BRX variants can boost seedling vigor and shed light on the activity of ancient, non-angiosperm BRX family proteins.
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Affiliation(s)
- Samuel W. H. Koh
- Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland
| | | | - Carlisle S. Bascom
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Eduardo Berenguer
- Laboratoire Reproduction et Développement des Plantes, ENS de Lyon, 69364 Lyon, France
| | - Gwyneth Ingram
- Laboratoire Reproduction et Développement des Plantes, ENS de Lyon, 69364 Lyon, France
| | - Mark Estelle
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Christian S. Hardtke
- Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland
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7
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Aliaga Fandino AC, Hardtke CS. Auxin transport in developing protophloem: A case study in canalization. JOURNAL OF PLANT PHYSIOLOGY 2022; 269:153594. [PMID: 34953411 DOI: 10.1016/j.jplph.2021.153594] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/03/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Spatiotemporal cues orchestrate the development of organs and cellular differentiation in multicellular organisms. For instance, in the root apical meristem an auxin gradient patterns the transition from stem cell maintenance to transit amplification and eventual differentiation. Among the proximal tissues generated by this growth apex, the early, so-called protophloem, is the first tissue to differentiate. This observation has been linked to increased auxin activity in the developing protophloem sieve element cell files as compared to the neighboring tissues. Here we review recent progress in the characterization of the unique mechanism by which auxin canalizes its activity in the developing protophloem and fine-tunes its own transport to guide proper timing of protophloem sieve element differentiation.
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Affiliation(s)
- Ana Cecilia Aliaga Fandino
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, 1015, Lausanne, Switzerland
| | - Christian S Hardtke
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, 1015, Lausanne, Switzerland.
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8
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Song XF, Hou XL, Liu CM. CLE peptides: critical regulators for stem cell maintenance in plants. PLANTA 2021; 255:5. [PMID: 34841457 DOI: 10.1007/s00425-021-03791-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 11/14/2021] [Indexed: 06/13/2023]
Abstract
Plant CLE peptides, which regulate stem cell maintenance in shoot and root meristems and in vascular bundles through LRR family receptor kinases, are novel, complex, and to some extent conserved. Over the past two decades, peptide ligands of the CLAVATA3 (CLV3) /Embryo Surrounding Region (CLE) family have been recognized as critical short- and long-distance communication signals in plants, especially for stem cell homeostasis, cell fate determination and physiological responses. Stem cells located at the shoot apical meristem (SAM), the root apical meristem (RAM) and the procambium divide and differentiate into specialized cells that form a variety of tissues such as epidermis, ground tissues, xylem and phloem. In the SAM of Arabidopsis (Arabidopsis thaliana), the CLV3 peptide restricts the number of stem cells via leucine-rich repeat (LRR)-type receptor kinases. In the RAM, root-active CLE peptides are critical negative regulators, while ROOT GROWTH FACTOR (RGF) peptides are positive regulators in stem cell maintenance. Among those root-active CLE peptides, CLE25 promotes, while CLE45 inhibits phloem differentiation. In vascular bundles, TRACHEARY ELEMENT DIFFERENTIATION INHIBITORY FACTOR (TDIF)/CLE41/CLE44 promotes procambium cell division, and prevents xylem differentiation. Orthologs of CLV3 have been identified in liverwort (Marchantia polymorpha), tomato (Solanum lycopersicum), rice (Oryza sativa), maize (Zea mays) and lotus (Lotus japonicas), suggesting that CLV3 is an evolutionarily conserved signal in stem cell maintenance. However, functional characterization of endogenous CLE peptides and corresponding receptor kinases, and the downstream signal transduction has been challenging due to their genome-wide redundancies and rapid evolution.
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Affiliation(s)
- Xiu-Fen Song
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiu-Li Hou
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Chun-Ming Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China.
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9
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Cui J, Peuke AD, Limami AM, Tcherkez G. Why is phloem sap nitrate kept low? PLANT, CELL & ENVIRONMENT 2021; 44:2838-2843. [PMID: 34075592 DOI: 10.1111/pce.14116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 05/10/2021] [Accepted: 05/23/2021] [Indexed: 06/12/2023]
Affiliation(s)
- Jing Cui
- Research School of Biology, ANU College of Science, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Andreas D Peuke
- ADP International Plant Science Consulting, Gundelfingen-Wildtal, Germany
| | - Anis M Limami
- Institut de Recherche en Horticulture et Semences, INRAe, Université d'Angers, Beaucouzé, France
| | - Guillaume Tcherkez
- Research School of Biology, ANU College of Science, Australian National University, Canberra, Australian Capital Territory, Australia
- Institut de Recherche en Horticulture et Semences, INRAe, Université d'Angers, Beaucouzé, France
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Koh SWH, Marhava P, Rana S, Graf A, Moret B, Bassukas AEL, Zourelidou M, Kolb M, Hammes UZ, Schwechheimer C, Hardtke CS. Mapping and engineering of auxin-induced plasma membrane dissociation in BRX family proteins. THE PLANT CELL 2021; 33:1945-1960. [PMID: 33751121 PMCID: PMC8290284 DOI: 10.1093/plcell/koab076] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 03/03/2021] [Indexed: 05/04/2023]
Abstract
Angiosperms have evolved the phloem for the long-distance transport of metabolites. The complex process of phloem development involves genes that only occur in vascular plant lineages. For example, in Arabidopsis thaliana, the BREVIS RADIX (BRX) gene is required for continuous root protophloem differentiation, together with PROTEIN KINASE ASSOCIATED WITH BRX (PAX). BRX and its BRX-LIKE (BRXL) homologs are composed of four highly conserved domains including the signature tandem BRX domains that are separated by variable spacers. Nevertheless, BRX family proteins have functionally diverged. For instance, BRXL2 can only partially replace BRX in the root protophloem. This divergence is reflected in physiologically relevant differences in protein behavior, such as auxin-induced plasma membrane dissociation of BRX, which is not observed for BRXL2. Here we dissected the differential functions of BRX family proteins using a set of amino acid substitutions and domain swaps. Our data suggest that the plasma membrane-associated tandem BRX domains are both necessary and sufficient to convey the biological outputs of BRX function and therefore constitute an important regulatory entity. Moreover, PAX target phosphosites in the linker between the two BRX domains mediate the auxin-induced plasma membrane dissociation. Engineering these sites into BRXL2 renders this modified protein auxin-responsive and thereby increases its biological activity in the root protophloem context.
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Affiliation(s)
- Samuel W H Koh
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | - Petra Marhava
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | - Surbhi Rana
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | - Alina Graf
- Plant Systems Biology, Technical University of Munich, Freising 85354, Germany
| | - Bernard Moret
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | | | - Melina Zourelidou
- Plant Systems Biology, Technical University of Munich, Freising 85354, Germany
| | - Martina Kolb
- Plant Systems Biology, Technical University of Munich, Freising 85354, Germany
| | - Ulrich Z Hammes
- Plant Systems Biology, Technical University of Munich, Freising 85354, Germany
| | - Claus Schwechheimer
- Plant Systems Biology, Technical University of Munich, Freising 85354, Germany
| | - Christian S Hardtke
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
- Author for correspondence:
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11
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Kuroda R, Kato M, Tsuge T, Aoyama T. Arabidopsis phosphatidylinositol 4-phosphate 5-kinase genes PIP5K7, PIP5K8, and PIP5K9 are redundantly involved in root growth adaptation to osmotic stress. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:913-927. [PMID: 33606325 DOI: 10.1111/tpj.15207] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
Phosphatidylinositol 4-phosphate 5-kinase (PIP5K) produces phosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P2 ), a signaling phospholipid critical for various cellular processes in eukaryotes. The Arabidopsis thaliana genome encodes 11 PIP5K genes. Of these, three type B PIP5K genes, PIP5K7, PIP5K8, and PIP5K9, constitute a subgroup highly conserved in land plants, suggesting that they retain a critical function shared by land plants. In this study, we comprehensively investigated the biological functions of the PIP5K7-9 subgroup genes. Reporter gene analyses revealed their preferential expression in meristematic and vascular tissues. Their YFP-fusion proteins localized primarily to the plasma membrane in root meristem epidermal cells. We selected a mutant line that was considered to be null for each gene. Under normal growth conditions, neither single mutants nor multiple mutants of any combination exhibited noticeable phenotypic changes. However, stress conditions with mannitol or NaCl suppressed main root growth and reduced proximal root meristem size to a greater extent in the pip5k7pip5k8pip5k9 triple mutant than in the wild type. In root meristem epidermal cells of the triple mutant, where plasma membrane localization of the PtdIns(4,5)P2 marker P24Y is impaired to a large extent, brefeldin A body formation is retarded compared with the wild type under hyperosmotic stress. These results indicate that PIP5K7, PIP5K8, and PIP5K9 are not required under normal growth conditions, but are redundantly involved in root growth adaptation to hyperosmotic conditions, possibly through the PtdIns(4,5)P2 function promoting plasma membrane recycling in root meristem cells.
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Affiliation(s)
- Ryo Kuroda
- Institute for Chemical Research, Kyoto University, Kyoto, 611-0011, Japan
| | - Mariko Kato
- Institute for Chemical Research, Kyoto University, Kyoto, 611-0011, Japan
| | - Tomohiko Tsuge
- Institute for Chemical Research, Kyoto University, Kyoto, 611-0011, Japan
| | - Takashi Aoyama
- Institute for Chemical Research, Kyoto University, Kyoto, 611-0011, Japan
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12
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Vijayan A, Tofanelli R, Strauss S, Cerrone L, Wolny A, Strohmeier J, Kreshuk A, Hamprecht FA, Smith RS, Schneitz K. A digital 3D reference atlas reveals cellular growth patterns shaping the Arabidopsis ovule. eLife 2021; 10:e63262. [PMID: 33404501 PMCID: PMC7787667 DOI: 10.7554/elife.63262] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 12/19/2020] [Indexed: 12/23/2022] Open
Abstract
A fundamental question in biology is how morphogenesis integrates the multitude of processes that act at different scales, ranging from the molecular control of gene expression to cellular coordination in a tissue. Using machine-learning-based digital image analysis, we generated a three-dimensional atlas of ovule development in Arabidopsis thaliana, enabling the quantitative spatio-temporal analysis of cellular and gene expression patterns with cell and tissue resolution. We discovered novel morphological manifestations of ovule polarity, a new mode of cell layer formation, and previously unrecognized subepidermal cell populations that initiate ovule curvature. The data suggest an irregular cellular build-up of WUSCHEL expression in the primordium and new functions for INNER NO OUTER in restricting nucellar cell proliferation and the organization of the interior chalaza. Our work demonstrates the analytical power of a three-dimensional digital representation when studying the morphogenesis of an organ of complex architecture that eventually consists of 1900 cells.
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Affiliation(s)
- Athul Vijayan
- Plant Developmental Biology, School of Life Sciences, Technical University of MunichFreisingGermany
| | - Rachele Tofanelli
- Plant Developmental Biology, School of Life Sciences, Technical University of MunichFreisingGermany
| | - Sören Strauss
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding ResearchCologneGermany
| | - Lorenzo Cerrone
- Heidelberg Collaboratory for Image Processing, Dept. of Physics and Astronomy, Heidelberg UniversityHeidelbergGermany
| | - Adrian Wolny
- Heidelberg Collaboratory for Image Processing, Dept. of Physics and Astronomy, Heidelberg UniversityHeidelbergGermany
- European Molecular Biology LaboratoryHeidelbergGermany
| | - Joanna Strohmeier
- Plant Developmental Biology, School of Life Sciences, Technical University of MunichFreisingGermany
| | - Anna Kreshuk
- European Molecular Biology LaboratoryHeidelbergGermany
| | - Fred A Hamprecht
- Heidelberg Collaboratory for Image Processing, Dept. of Physics and Astronomy, Heidelberg UniversityHeidelbergGermany
| | - Richard S Smith
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding ResearchCologneGermany
| | - Kay Schneitz
- Plant Developmental Biology, School of Life Sciences, Technical University of MunichFreisingGermany
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13
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Wallner ES. The value of asymmetry: how polarity proteins determine plant growth and morphology. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:5733-5739. [PMID: 32687194 PMCID: PMC7888286 DOI: 10.1093/jxb/eraa329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/14/2020] [Indexed: 06/11/2023]
Abstract
Cell polarity is indispensable for forming complex multicellular organisms. Proteins that polarize at specific plasma membrane domains can either serve as scaffolds for effectors or coordinate intercellular communication and transport. Here, I give an overview of polarity protein complexes and their fundamental importance for plant development, and summarize novel mechanistic insights into their molecular networks. Examples are presented for proteins that polarize at specific plasma membrane domains to orient cell division planes, alter cell fate progression, control transport, direct cell growth, read global polarity axes, or integrate external stimuli into plant growth. The recent advances in characterizing protein polarity during plant development enable a better understanding of coordinated plant growth and open up intriguing paths that could provide a means to modulate plant morphology and adaptability in the future.
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Zarza X, Van Wijk R, Shabala L, Hunkeler A, Lefebvre M, Rodriguez‐Villalón A, Shabala S, Tiburcio AF, Heilmann I, Munnik T. Lipid kinases PIP5K7 and PIP5K9 are required for polyamine-triggered K + efflux in Arabidopsis roots. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:416-432. [PMID: 32666545 PMCID: PMC7693229 DOI: 10.1111/tpj.14932] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/30/2020] [Accepted: 07/07/2020] [Indexed: 05/03/2023]
Abstract
Polyamines, such as putrescine, spermidine and spermine (Spm), are low-molecular-weight polycationic molecules present in all living organisms. Despite their implication in plant cellular processes, little is known about their molecular mode of action. Here, we demonstrate that polyamines trigger a rapid increase in the regulatory membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP2 ), and that this increase is required for polyamine effects on K+ efflux in Arabidopsis roots. Using in vivo 32 Pi -labelling of Arabidopsis seedlings, low physiological (μm) concentrations of Spm were found to promote a rapid PIP2 increase in roots that was time- and dose-dependent. Confocal imaging of a genetically encoded PIP2 biosensor revealed that this increase was triggered at the plasma membrane. Differential 32 Pi -labelling suggested that the increase in PIP2 was generated through activation of phosphatidylinositol 4-phosphate 5-kinase (PIP5K) activity rather than inhibition of a phospholipase C or PIP2 5-phosphatase activity. Systematic analysis of transfer DNA insertion mutants identified PIP5K7 and PIP5K9 as the main candidates involved in the Spm-induced PIP2 response. Using non-invasive microelectrode ion flux estimation, we discovered that the Spm-triggered K+ efflux response was strongly reduced in pip5k7 pip5k9 seedlings. Together, our results provide biochemical and genetic evidence for a physiological role of PIP2 in polyamine-mediated signalling controlling K+ flux in plants.
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Affiliation(s)
- Xavier Zarza
- Research Cluster Green Life SciencesSection Plant Cell BiologySwammerdam Institute for Life SciencesUniversity of AmsterdamPO Box 94215Amsterdam1090 GEThe Netherlands
| | - Ringo Van Wijk
- Research Cluster Green Life SciencesSection Plant Cell BiologySwammerdam Institute for Life SciencesUniversity of AmsterdamPO Box 94215Amsterdam1090 GEThe Netherlands
| | - Lana Shabala
- Tasmanian Institute of AgricultureUniversity of TasmaniaHobartAustralia
| | - Anna Hunkeler
- Department of BiologyInstitute of Agricultural ScienceSwiss Federal Institute of Technology in ZurichZurichSwitzerland
| | - Matthew Lefebvre
- Research Cluster Green Life SciencesSection Plant Cell BiologySwammerdam Institute for Life SciencesUniversity of AmsterdamPO Box 94215Amsterdam1090 GEThe Netherlands
| | - Antia Rodriguez‐Villalón
- Department of BiologyInstitute of Agricultural ScienceSwiss Federal Institute of Technology in ZurichZurichSwitzerland
| | - Sergey Shabala
- Tasmanian Institute of AgricultureUniversity of TasmaniaHobartAustralia
- International Research Centre for Environmental Membrane BiologyFoshan UniversityFoshanChina
| | - Antonio F. Tiburcio
- Dept. of Natural Products, Plant Biology and Soil ScienceUniversity of BarcelonaBarcelonaSpain
| | - Ingo Heilmann
- Dept of Cellular BiochemistryInstitute of Biochemistry and BiotechnologyMartin Luther University Halle‐WittenbergHalle (Saale)Germany
| | - Teun Munnik
- Research Cluster Green Life SciencesSection Plant Cell BiologySwammerdam Institute for Life SciencesUniversity of AmsterdamPO Box 94215Amsterdam1090 GEThe Netherlands
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15
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Ren SC, Song XF, Chen WQ, Lu R, Lucas WJ, Liu CM. CLE25 peptide regulates phloem initiation in Arabidopsis through a CLERK-CLV2 receptor complex. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2019; 61:1043-1061. [PMID: 31127689 DOI: 10.1111/jipb.12846] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 05/24/2019] [Indexed: 05/29/2023]
Abstract
The phloem, located within the vascular system, is critical for delivery of nutrients and signaling molecules throughout the plant body. Although the morphological process and several factors regulating phloem differentiation have been reported, the molecular mechanism underlying its initiation remains largely unknown. Here, we report that the small peptide-coding gene, CLAVATA 3 (CLV3)/EMBEYO SURROUNDING REGION 25 (CLE25), the expression of which begins in provascular initial cells of 64-cell-staged embryos, and continues in sieve element-procambium stem cells and phloem lineage cells, during post-embryonic root development, facilitates phloem initiation in Arabidopsis. Knockout of CLE25 led to delayed protophloem formation, and in situ expression of an antagonistic CLE25G6T peptide compromised the fate-determining periclinal division of the sieve element precursor cell and the continuity of the phloem in roots. In stems of CLE25G6T plants the phloem formation was also compromised, and procambial cells were over-accumulated. Genetic and biochemical analyses indicated that a complex, consisting of the CLE-RESISTANT RECEPTOR KINASE (CLERK) leucine-rich repeat (LRR) receptor kinase and the CLV2 LRR receptor-like protein, is involved in perceiving the CLE25 peptide. Similar to CLE25, CLERK was also expressed during early embryogenesis. Taken together, our findings suggest that CLE25 regulates phloem initiation in Arabidopsis through a CLERK-CLV2 receptor complex.
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Affiliation(s)
- Shi-Chao Ren
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Fragrant Hill, Beijing, 100093, China
| | - Xiu-Fen Song
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Fragrant Hill, Beijing, 100093, China
| | - Wen-Qiang Chen
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Fragrant Hill, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ran Lu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Fragrant Hill, Beijing, 100093, China
| | - William J Lucas
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, CA, 95616, USA
| | - Chun-Ming Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Fragrant Hill, Beijing, 100093, China
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
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16
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Stadler R, Sauer N. The AtSUC2 Promoter: A Powerful Tool to Study Phloem Physiology and Development. Methods Mol Biol 2019; 2014:267-287. [PMID: 31197803 DOI: 10.1007/978-1-4939-9562-2_22] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The sucrose carrier AtSUC2 of Arabidopsis thaliana is localized in the phloem, where it catalyzes the uptake of sucrose from the apoplast into companion cells. Imported sucrose moves passively via plasmodesmata from the companion cells into the neighboring sieve elements that distribute this disaccharide to the different sink organs. Phloem loading of sucrose by the AtSUC2 protein is an essential process, and mutants lacking this protein stay tiny, develop no or only few flowers, and have a strongly reduced root system. The promoter of the AtSUC2 gene is active exclusively in companion cells of the phloem. Moreover, it drives very strong expression not only in Arabidopsis, but also in all plant species tested so far, including monocot species. Due to these features, the AtSUC2 promoter has become an important tool in diverse areas of plant research during the last two decades. It was used to study phloem development and function including phloem loading and unloading. Furthermore, it was helpful in analyzing the pathways of posttranscriptional silencing by RNA interference, the regulation of flowering, mechanisms of nutrient withdrawal by phloem-feeding pathogens, and other physiological functions that are related to long distance transport. The present paper gives an overview of different approaches in plant research that utilized the strong and companion cell-specific expression of own or foreign genes driven by the AtSUC2 promoter.
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Affiliation(s)
- Ruth Stadler
- Molecular Plant Physiology, Department of Biology, University of Erlangen-Nuremberg, Erlangen, Germany.
| | - Norbert Sauer
- Molecular Plant Physiology, Department of Biology, University of Erlangen-Nuremberg, Erlangen, Germany
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17
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Hellmann E, Ko D, Ruonala R, Helariutta Y. Plant Vascular Tissues-Connecting Tissue Comes in All Shapes. PLANTS (BASEL, SWITZERLAND) 2018; 7:E109. [PMID: 30551673 PMCID: PMC6313914 DOI: 10.3390/plants7040109] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 11/23/2018] [Accepted: 12/07/2018] [Indexed: 12/23/2022]
Abstract
For centuries, humans have grown and used structures based on vascular tissues in plants. One could imagine that life would have developed differently without wood as a resource for building material, paper, heating energy, or fuel and without edible tubers as a food source. In this review, we will summarise the status of research on Arabidopsis thaliana vascular development and subsequently focus on how this knowledge has been applied and expanded in research on the wood of trees and storage organs of crop plants. We will conclude with an outlook on interesting open questions and exciting new research opportunities in this growing and important field.
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Affiliation(s)
- Eva Hellmann
- The Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, UK.
| | - Donghwi Ko
- The Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, UK.
| | - Raili Ruonala
- The Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, UK.
- Institute of Biotechnology, Department of Biological and Environmental Sciences, University of Helsinki, FI-00014 Helsinki, Finland.
| | - Ykä Helariutta
- The Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, UK.
- Institute of Biotechnology, Department of Biological and Environmental Sciences, University of Helsinki, FI-00014 Helsinki, Finland.
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18
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Anne P, Hardtke CS. Phloem function and development-biophysics meets genetics. CURRENT OPINION IN PLANT BIOLOGY 2018; 43:22-28. [PMID: 29278791 DOI: 10.1016/j.pbi.2017.12.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 11/10/2017] [Accepted: 12/12/2017] [Indexed: 05/07/2023]
Abstract
Evolution of the vascular tissues allowed plants to efficiently settle land, occupy new ecological niches, and thereby crucially shape earth's biosphere. Of the two conducting cell types in the plant vasculature, the tubular network of phloem sieve elements transports phloem sap from source to sink organs. Recent years have witnessed the identification of ever more regulators of sieve element differentiation, as well as a more detailed understanding of phloem physiology and function. From molecular regulators of the commitment to sieve element fate, to enzymatic executors of the differentiation process, the toolbox to investigate sieve element formation has been greatly enlarged. To connect the various players in different genetic layers, and thus to ultimately attain a comprehensive description and understanding of sieve element development at the molecular level, appears to be within reach.
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Affiliation(s)
- Pauline Anne
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Christian S Hardtke
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland.
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19
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Ruiz Sola MA, Coiro M, Crivelli S, Zeeman SC, Schmidt Kjølner Hansen S, Truernit E. OCTOPUS-LIKE 2, a novel player in Arabidopsis root and vascular development, reveals a key role for OCTOPUS family genes in root metaphloem sieve tube differentiation. THE NEW PHYTOLOGIST 2017; 216:1191-1204. [PMID: 28877333 DOI: 10.1111/nph.14751] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 07/16/2017] [Indexed: 06/07/2023]
Abstract
Protophloem and metaphloem sieve tubes are essential for transporting carbohydrates and signalling molecules towards sink tissues. OCTOPUS (OPS) was previously identified as an important regulator of protophloem differentiation in Arabidopsis roots. Here, we investigated the role of OCTOPUS-LIKE 2 (OPL2), a gene homologous to OPS. OPL2 expression patterns were analysed, and functional equivalence of OPS and OPL2 was tested. Mutant and double mutant phenotypes were investigated. OPS and OPL2 displayed overlapping expression patterns and a high degree of functional overlap. A mutation in OPL2 revealed redundant functions of OPS and OPL2 in developmental processes in which OPS was known to play a role, notably cotyledon vascular patterning and protophloem development. Moreover, we also uncovered redundant roles for OPS and OPL2 in leaf vascular patterning and, most interestingly, metaphloem sieve tube differentiation. Our results reveal a novel OPS-like protein that, together with OPS, is an important regulator of vascular patterning, root growth and phloem development. OPS and OPL2 are the first genes identified that play a role in metaphloem sieve tube differentiation.
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Affiliation(s)
- M Aguila Ruiz Sola
- Department of Biology, Institute of Molecular Plant Biology, ETH Zurich, Universitätsstrasse 2, 8092, Zurich, Switzerland
| | - Mario Coiro
- Department of Biology, Institute of Molecular Plant Biology, ETH Zurich, Universitätsstrasse 2, 8092, Zurich, Switzerland
| | - Simona Crivelli
- Department of Biology, Institute of Molecular Plant Biology, ETH Zurich, Universitätsstrasse 2, 8092, Zurich, Switzerland
| | - Samuel C Zeeman
- Department of Biology, Institute of Molecular Plant Biology, ETH Zurich, Universitätsstrasse 2, 8092, Zurich, Switzerland
| | - Signe Schmidt Kjølner Hansen
- Department of Biology, Institute of Molecular Plant Biology, ETH Zurich, Universitätsstrasse 2, 8092, Zurich, Switzerland
| | - Elisabeth Truernit
- Department of Biology, Institute of Molecular Plant Biology, ETH Zurich, Universitätsstrasse 2, 8092, Zurich, Switzerland
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20
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Affiliation(s)
- Raili Ruonala
- Institute of Biotechnology and Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland
- The Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, United Kingdom;, ,
| | - Donghwi Ko
- The Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, United Kingdom;, ,
| | - Ykä Helariutta
- Institute of Biotechnology and Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland
- The Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, United Kingdom;, ,
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21
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Abstract
Vascular tissue, comprising xylem and phloem, is responsible for the transport of water and nutrients throughout the plant body. Such tissue is continually produced from stable populations of stem cells, specifically the procambium during primary growth and the cambium during secondary growth. As the majority of plant biomass is produced by the cambium, there is an obvious demand for an understanding of the genetic mechanisms that control the rate of vascular cell division. Moreover, wood is an industrially important product of the cambium, and research is beginning to uncover similar mechanisms in trees such as poplar. This review focuses upon recent work that has identified the major molecular pathways that regulate procambial and cambial activity.
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Affiliation(s)
- Liam Campbell
- University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Simon Turner
- University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
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22
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Ohashi-Ito K, Fukuda H. Functional mechanism of bHLH complexes during early vascular development. CURRENT OPINION IN PLANT BIOLOGY 2016; 33:42-47. [PMID: 27314622 DOI: 10.1016/j.pbi.2016.06.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 06/01/2016] [Accepted: 06/01/2016] [Indexed: 05/27/2023]
Abstract
The vascular system spreads throughout the plant body. This highly organized network contains several types of cells. Vascular cell development is initiated during embryogenesis, and then vascular cells proliferate, form a vascular pattern, and commit to specific cell fates. Recent molecular genetics and modeling approaches have increased our understanding of the molecular mechanisms underlying early vascular development. Early events during vascular development are tightly linked and controlled by transcriptional complexes consisting of LONESOME HIGHWAY (LHW) and TARGET OF MONOPTEROS5 (TMO5) families. The role of LHW-TMO5 is tightly coupled with biosynthesis and/or signaling of phytohormones such as auxin and cytokinin. In this review, we discuss the regulatory network mediated by LHW-TMO5 during early vascular development.
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Affiliation(s)
- Kyoko Ohashi-Ito
- Department Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan.
| | - Hiroo Fukuda
- Department Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan.
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23
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Rodriguez-Villalon A. Wiring a plant: genetic networks for phloem formation in Arabidopsis thaliana roots. THE NEW PHYTOLOGIST 2016; 210:45-50. [PMID: 26171671 DOI: 10.1111/nph.13527] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 04/25/2015] [Indexed: 05/07/2023]
Abstract
In plants, phloem conduits form a specialized vascular network mediating the exchange of nutrients and signaling molecules between distantly separated organs. To become effective transport elements, protophloem cells undergo a rather unique, differentiation program that involves nucleus degradation, organelle rearrangement and cell wall thickening. Yet, protophloem sieve elements remain alive because their essential metabolic functions are supported by their neighboring companion cells. In spite of the importance of the phloem, the molecular mechanisms orchestrating protophloem specification and differentiation remain still poorly understood. In this review, I provide a summary of recent discoveries regarding morphogenetic events that determine phloem formation, and also a discussion of the systemic effects on root architecture derived from impaired protophloem differentiation programs.
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Affiliation(s)
- Antia Rodriguez-Villalon
- Department of Biology, Swiss Federal Institute of Technology (ETH-Z), CH-8092, Zurich, Switzerland
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24
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Gujas B, Rodriguez-Villalon A. Plant Phosphoglycerolipids: The Gatekeepers of Vascular Cell Differentiation. FRONTIERS IN PLANT SCIENCE 2016; 7:103. [PMID: 26904069 PMCID: PMC4751917 DOI: 10.3389/fpls.2016.00103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 01/19/2016] [Indexed: 05/31/2023]
Abstract
In higher plants, the plant vascular system has evolved as an inter-organ communication network essential to deliver a wide range of signaling factors among distantly separated organs. To become conductive elements, phloem and xylem cells undergo a drastic differentiation program that involves the degradation of the majority of their organelles. While the molecular mechanisms regulating such complex process remain poorly understood, it is nowadays clear that phosphoglycerolipids display a pivotal role in the regulation of vascular tissue formation. In animal cells, this class of lipids is known to mediate acute responses as signal transducers and also act as constitutive signals that help defining organelle identity. Their rapid turnover, asymmetrical distribution across subcellular compartments as well as their ability to rearrange cytoskeleton fibers make phosphoglycerolipids excellent candidates to regulate complex morphogenetic processes such as vascular differentiation. Therefore, in this review we aim to summarize, emphasize and connect our current understanding about the involvement of phosphoglycerolipids in phloem and xylem differentiation.
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25
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Adibi M, Yoshida S, Weijers D, Fleck C. Centering the Organizing Center in the Arabidopsis thaliana Shoot Apical Meristem by a Combination of Cytokinin Signaling and Self-Organization. PLoS One 2016; 11:e0147830. [PMID: 26872130 PMCID: PMC4752473 DOI: 10.1371/journal.pone.0147830] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 01/08/2016] [Indexed: 12/15/2022] Open
Abstract
Plants have the ability to continously generate new organs by maintaining populations of stem cells throught their lives. The shoot apical meristem (SAM) provides a stable environment for the maintenance of stem cells. All cells inside the SAM divide, yet boundaries and patterns are maintained. Experimental evidence indicates that patterning is independent of cell lineage, thus a dynamic self-regulatory mechanism is required. A pivotal role in the organization of the SAM is played by the WUSCHEL gene (WUS). An important question in this regard is that how WUS expression is positioned in the SAM via a cell-lineage independent signaling mechanism. In this study we demonstrate via mathematical modeling that a combination of an inhibitor of the Cytokinin (CK) receptor, Arabidopsis histidine kinase 4 (AHK4) and two morphogens originating from the top cell layer, can plausibly account for the cell lineage-independent centering of WUS expression within SAM. Furthermore, our laser ablation and microsurgical experiments support the hypothesis that patterning in SAM occurs at the level of CK reception and signaling. The model suggests that the interplay between CK signaling, WUS/CLV feedback loop and boundary signals can account for positioning of the WUS expression, and provides directions for further experimental investigation.
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Affiliation(s)
- Milad Adibi
- Laboratory of Systems and Synthetic Biology, Wageningen University, Wageningen, the Netherlands
- * E-mail: (MA); (CF)
| | - Saiko Yoshida
- Laboratory of Biochemistry, Wageningen University, Wageningen, the Netherlands
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, Wageningen, the Netherlands
| | - Christian Fleck
- Laboratory of Systems and Synthetic Biology, Wageningen University, Wageningen, the Netherlands
- * E-mail: (MA); (CF)
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26
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Müller B, Fastner A, Karmann J, Mansch V, Hoffmann T, Schwab W, Suter-Grotemeyer M, Rentsch D, Truernit E, Ladwig F, Bleckmann A, Dresselhaus T, Hammes U. Amino Acid Export in Developing Arabidopsis Seeds Depends on UmamiT Facilitators. Curr Biol 2015; 25:3126-31. [DOI: 10.1016/j.cub.2015.10.038] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 10/12/2015] [Accepted: 10/15/2015] [Indexed: 12/26/2022]
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27
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De Rybel B, Mähönen AP, Helariutta Y, Weijers D. Plant vascular development: from early specification to differentiation. Nat Rev Mol Cell Biol 2015; 17:30-40. [PMID: 26580717 DOI: 10.1038/nrm.2015.6] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Vascular tissues in plants are crucial to provide physical support and to transport water, sugars and hormones and other small signalling molecules throughout the plant. Recent genetic and molecular studies have identified interconnections among some of the major signalling networks that regulate plant vascular development. Using Arabidopsis thaliana as a model system, these studies enable the description of vascular development from the earliest tissue specification events during embryogenesis to the differentiation of phloem and xylem tissues. Moreover, we propose a model for how oriented cell divisions give rise to a three-dimensional vascular bundle within the root meristem.
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Affiliation(s)
- Bert De Rybel
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703HA Wageningen, The Netherlands.,Department of Plant Systems Biology, VIB-Ghent University, Technologiepark 927, B-9052 Ghent, Belgium.,Department of Plant Biotechnology and Genetics, Ghent University, Technologiepark 927, B-9052 Ghent, Belgium
| | - Ari Pekka Mähönen
- Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, FIN-00014, Finland
| | - Yrjö Helariutta
- Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, FIN-00014, Finland.,Sainsbury Laboratory, Cambridge University, Bateman Street, Cambridge, CB2 1LR, UK
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703HA Wageningen, The Netherlands
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28
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Kurihara D, Mizuta Y, Sato Y, Higashiyama T. ClearSee: a rapid optical clearing reagent for whole-plant fluorescence imaging. Development 2015; 142:4168-79. [PMID: 26493404 PMCID: PMC4712841 DOI: 10.1242/dev.127613] [Citation(s) in RCA: 299] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 10/12/2015] [Indexed: 12/18/2022]
Abstract
Imaging techniques for visualizing and analyzing precise morphology and gene expression patterns are essential for understanding biological processes during development in all organisms. With the aid of chemical screening, we developed a clearing method using chemical solutions, termed ClearSee, for deep imaging of morphology and gene expression in plant tissues. ClearSee rapidly diminishes chlorophyll autofluorescence while maintaining fluorescent protein stability. By adjusting the refractive index mismatch, whole-organ and whole-plant imaging can be performed by both confocal and two-photon excitation microscopy in ClearSee-treated samples. Moreover, ClearSee is applicable to multicolor imaging of fluorescent proteins to allow structural analysis of multiple gene expression. Given that ClearSee is compatible with staining by chemical dyes, the technique is useful for deep imaging in conjunction with genetic markers and for plant species not amenable to transgenic approaches. This method is useful for whole imaging for intact morphology and will help to accelerate the discovery of new phenomena in plant biological research. Summary: The optical clearing reagent ClearSee improves the multicolor imaging of fluorescent proteins and dyes and allows the structural analysis of gene expression patterns in multiple plant tissues.
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Affiliation(s)
- Daisuke Kurihara
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan Higashiyama Live-Holonics Project, ERATO, JST, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Yoko Mizuta
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan Higashiyama Live-Holonics Project, ERATO, JST, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Yoshikatsu Sato
- Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Tetsuya Higashiyama
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan Higashiyama Live-Holonics Project, ERATO, JST, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
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29
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OCTOPUS Negatively Regulates BIN2 to Control Phloem Differentiation in Arabidopsis thaliana. Curr Biol 2015; 25:2584-90. [DOI: 10.1016/j.cub.2015.08.033] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 07/24/2015] [Accepted: 08/17/2015] [Indexed: 11/17/2022]
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30
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Pesacreta TC. F-actin distribution in root primary tissues of several seed plant species. AMERICAN JOURNAL OF BOTANY 2015; 102:1422-1433. [PMID: 26391707 DOI: 10.3732/ajb.1500179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 08/13/2015] [Indexed: 06/05/2023]
Abstract
PREMISE OF THE STUDY Primary vascular tissues of angiosperm and gymnosperm roots have significant anatomical differences. In gymnosperms, lack of protophloem sieve elements indicates a lengthy parenchymatous pathway for nutrient transport to the root apical meristem (RAM). Because F-actin is an essential component of transport in parenchyma cells, the distribution of F-actin was determined and compared among roots of several angiosperm and gymnosperm species. METHODS Roots were chemically fixed and sectioned by hand to enable rapid production of many sections for labeling F-actin with phalloidin. KEY RESULTS In angiosperm and gymnosperm root tips, relative intensity of F-actin labeling was highest in primary vascular tissues. Parenchyma cells in and around protophloem tended to have more F-actin while cells in cortical and protoxylem tissues tended to have less. In gymnosperms, phloem parenchyma was intensely labeled for several millimeters distal to the root apical meristem (RAM), and the F-actin is mostly composed of bundles that lie parallel to the root longitudinal axis. This orientation differed from the multidirectional arrangement of F-actin filaments in cortical cells. In angiosperms, intense F-actin labeling of pericycle and phloem parenchyma cells occurred around the first mature sieve elements. CONCLUSIONS F-actin is concentrated in the vascular cylinder, commonly in primary phloem parenchyma. In gymnosperms, the absence of sieve elements suggests that cytoplasmic streaming has a role in some aspect of phloem transport or unloading. In angiosperms, the region of intense F-actin labeling in the phloem parenchyma is limited to the extreme terminal portion of primary phloem where unloading of the earliest mature sieve elements occurs.
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Affiliation(s)
- Thomas C Pesacreta
- Microscopy Center, University of Louisiana Lafayette, P.O. Box 42451, Lafayette, Louisiana 70504 USA
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31
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Růžička K, Ursache R, Hejátko J, Helariutta Y. Xylem development - from the cradle to the grave. THE NEW PHYTOLOGIST 2015; 207:519-35. [PMID: 25809158 DOI: 10.1111/nph.13383] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 02/21/2015] [Indexed: 05/06/2023]
Abstract
The development and growth of plants, as well as their successful adaptation to a variety of environments, is highly dependent on the conduction of water, nutrients and other important molecules throughout the plant body. Xylem is a specialized vascular tissue that serves as a conduit of water and minerals and provides mechanical support for upright growth. Wood, also known as secondary xylem, constitutes the major part of mature woody stems and roots. In the past two decades, a number of key factors including hormones, signal transducers and (post)transcriptional regulators have been shown to control xylem formation. We outline the main mechanisms shown to be essential for xylem development in various plant species, with an emphasis on Arabidopsis thaliana, as well as several tree species where xylem has a long history of investigation. We also summarize the processes which have been shown to be instrumental during xylem maturation. This includes mechanisms of cell wall formation and cell death which collectively complete xylem cell fate.
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Affiliation(s)
- Kamil Růžička
- Department of Functional Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 25, Brno, CZ-62500, Czech Republic
| | - Robertas Ursache
- Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, CB2 1LR, UK
| | - Jan Hejátko
- Department of Functional Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 25, Brno, CZ-62500, Czech Republic
| | - Ykä Helariutta
- Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, CB2 1LR, UK
- Institute of Biotechnology, University of Helsinki, PO Box 65, Helsinki, FIN-00014, Finland
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32
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Jouannet V, Brackmann K, Greb T. (Pro)cambium formation and proliferation: two sides of the same coin? CURRENT OPINION IN PLANT BIOLOGY 2015; 23:54-60. [PMID: 25449727 PMCID: PMC4353845 DOI: 10.1016/j.pbi.2014.10.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 10/16/2014] [Accepted: 10/16/2014] [Indexed: 05/17/2023]
Abstract
The body of higher plants is usually pervaded by the (pro)cambium, a reticulate system of meristematic cells harboring the potential for producing vascular tissues at critical times and places. The (pro)cambium thereby provides the basis for the differential modulation of long-distance transport capacities and plant body stability. Distinct regulatory networks responsible for the initiation and proliferation of (pro)cambium cells have been identified. However, although a tight interaction between these networks can be expected, connections have been established only sporadically. Here we highlight recent discoveries of how (pro)cambium development is regulated and discuss possible interfaces between networks regulating two processes: (pro)cambium formation and cambium proliferation.
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Affiliation(s)
- Virginie Jouannet
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Klaus Brackmann
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Thomas Greb
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.
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33
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Konishi M, Donner TJ, Scarpella E, Yanagisawa S. MONOPTEROS directly activates the auxin-inducible promoter of the Dof5.8 transcription factor gene in Arabidopsis thaliana leaf provascular cells. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:283-91. [PMID: 25336688 PMCID: PMC4265163 DOI: 10.1093/jxb/eru418] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
MONOPTEROS (MP) is an auxin-responsive transcription factor that is required for primary root formation and vascular development, whereas Dof5.8 is a Dof-class transcription factor whose gene is expressed in embryos as well as the pre- and procambial cells in the leaf primordium in Arabidopsis thaliana. In this study, it is shown that MP directly activates the Dof5.8 promoter. Although no apparent phenotype of the single dof5.8 mutants was found, phenotypic analysis with the mp dof5.8 double mutants revealed that mutations within Dof5.8 enhanced the phenotype of a weak allele of mp, with an increase in the penetrance of the 'rootless' phenotype and a reduction in the number of cotyledons. Furthermore, interestingly, although mp mutants showed reduced vascular pattern complexity in cotyledons, the mp dof5.8 double mutants displayed both more simplex and more complex vascular patterns in individual cotyledons. These results imply that the product of Dof5.8 whose expression is regulated by MP at least in part might be involved in multiple processes controlled by MP.
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Affiliation(s)
- Mineko Konishi
- Biotechnology Research Center, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Tyler J Donner
- Department of Biological Sciences, University of Alberta, CW-405 Biological Sciences Building, Edmonton, Alberta, Canada T6G 2E9
| | - Enrico Scarpella
- Department of Biological Sciences, University of Alberta, CW-405 Biological Sciences Building, Edmonton, Alberta, Canada T6G 2E9
| | - Shuichi Yanagisawa
- Biotechnology Research Center, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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34
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Guerriero G, Sergeant K, Hausman JF. Wood biosynthesis and typologies: a molecular rhapsody. TREE PHYSIOLOGY 2014; 34:839-55. [PMID: 24876292 DOI: 10.1093/treephys/tpu031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Wood represents one of the most important renewable commodities for humanity and plays a crucial role in terrestrial ecosystem carbon-cycling. Wood formation is the result of a multitude of events that require the concerted action of endogenous and exogenous factors under the influence of photoperiod, for instance genes and plant growth regulators. Beyond providing mechanical support and being responsible for the increase in stem radial diameter, woody tissues constitute the vascular system of trees and are capable of reacting to environmental stimuli, and as such are therefore quite plastic and responsive. Despite the ecological and economic importance of wood, not all aspects of its formation have been unveiled. Many gaps in our knowledge are still present, which hinder the maximal exploitation of this precious bioresource. This review aims at surveying the current knowledge of wood formation and the available molecular data addressing the relationship between wood production and environmental factors, which have crucial influences on the rhythmic regulation of cambial activity and exert profound effects on tree stem growth, wood yield and properties. We will here go beyond wood sensu stricto, i.e., secondary xylem, and extend our survey to other tissues, namely vascular cambium, phloem and fibres. The purpose is to provide the reader with an overview of the complexity of the topic and to highlight the importance of progressing in the future towards an integrated knowledge on the subject.
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Affiliation(s)
- Gea Guerriero
- Department of Environment and Agro-biotechnologies (EVA), Centre de Recherche Public-Gabriel Lippmann, 41, Rue du Brill, L-4422 Belvaux, Luxembourg
| | - Kjell Sergeant
- Department of Environment and Agro-biotechnologies (EVA), Centre de Recherche Public-Gabriel Lippmann, 41, Rue du Brill, L-4422 Belvaux, Luxembourg
| | - Jean-Francois Hausman
- Department of Environment and Agro-biotechnologies (EVA), Centre de Recherche Public-Gabriel Lippmann, 41, Rue du Brill, L-4422 Belvaux, Luxembourg;
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35
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De Rybel B, Breda AS, Weijers D. Prenatal plumbing--vascular tissue formation in the plant embryo. PHYSIOLOGIA PLANTARUM 2014; 151:126-133. [PMID: 24032409 DOI: 10.1111/ppl.12091] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 07/01/2013] [Accepted: 07/10/2013] [Indexed: 06/02/2023]
Abstract
The first vascular tissue precursors are specified early during embryogenesis. These precursors give rise to the multi-layered cylinder of hypocotyl and root through controlled, oriented divisions. Concomitant with its growth, the bundle is patterned into xylem and phloem tissues, and intervening procambial cells. These patterns are later maintained during post-embryonic growth and vascular cells will eventually differentiate, displaying characteristic secondary cell wall modifications. Given that the vascular system forms de novo in a simple yet predictable fashion, the embryo provides an excellent model system to study early developmental aspects of vascular tissue formation. However, the benefits of this model are only beginning to be exploited, and most knowledge about the vascular development is derived from growing post-embryonic tissues. Importantly, it is unclear how much of these established post-embryonic mechanisms can be extrapolated to tissue formation during embryogenesis. Here we review concepts established in the model plant Arabidopsis thaliana and focus on recent advances made in understanding embryonic vascular development.
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Affiliation(s)
- Bert De Rybel
- Laboratory of Biochemistry, Wageningen University, Wageningen, 6703HA, the Netherlands
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36
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Lin IW, Sosso D, Chen LQ, Gase K, Kim SG, Kessler D, Klinkenberg PM, Gorder MK, Hou BH, Qu XQ, Carter CJ, Baldwin IT, Frommer WB. Nectar secretion requires sucrose phosphate synthases and the sugar transporter SWEET9. Nature 2014; 508:546-9. [PMID: 24670640 DOI: 10.1038/nature13082] [Citation(s) in RCA: 244] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 01/27/2014] [Indexed: 01/09/2023]
Abstract
Angiosperms developed floral nectaries that reward pollinating insects. Although nectar function and composition have been characterized, the mechanism of nectar secretion has remained unclear. Here we identify SWEET9 as a nectary-specific sugar transporter in three eudicot species: Arabidopsis thaliana, Brassica rapa (extrastaminal nectaries) and Nicotiana attenuata (gynoecial nectaries). We show that SWEET9 is essential for nectar production and can function as an efflux transporter. We also show that sucrose phosphate synthase genes, encoding key enzymes for sucrose biosynthesis, are highly expressed in nectaries and that their expression is also essential for nectar secretion. Together these data are consistent with a model in which sucrose is synthesized in the nectary parenchyma and subsequently secreted into the extracellular space via SWEET9, where sucrose is hydrolysed by an apoplasmic invertase to produce a mixture of sucrose, glucose and fructose. The recruitment of SWEET9 for sucrose export may have been a key innovation, and could have coincided with the evolution of core eudicots and contributed to the evolution of nectar secretion to reward pollinators.
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Affiliation(s)
- I Winnie Lin
- 1] Department of Biology, Stanford University, Stanford, California 94305, USA [2] Carnegie Institution for Science, 260 Panama Street, Stanford, California 94305, USA
| | - Davide Sosso
- 1] Department of Biology, Stanford University, Stanford, California 94305, USA [2] Carnegie Institution for Science, 260 Panama Street, Stanford, California 94305, USA
| | - Li-Qing Chen
- Carnegie Institution for Science, 260 Panama Street, Stanford, California 94305, USA
| | - Klaus Gase
- Max Planck Institute for Chemical Ecology, Jena D-07745, Germany
| | - Sang-Gyu Kim
- Max Planck Institute for Chemical Ecology, Jena D-07745, Germany
| | - Danny Kessler
- Max Planck Institute for Chemical Ecology, Jena D-07745, Germany
| | - Peter M Klinkenberg
- 1] Department of Biology, University of Minnesota Duluth, Duluth, Minnesota 55812, USA [2] Department of Plant Biology, University of Minnesota, St Paul, Minnesota 55108, USA
| | - Molly K Gorder
- 1] Department of Biology, University of Minnesota Duluth, Duluth, Minnesota 55812, USA [2] Department of Plant Biology, University of Minnesota, St Paul, Minnesota 55108, USA
| | - Bi-Huei Hou
- Carnegie Institution for Science, 260 Panama Street, Stanford, California 94305, USA
| | - Xiao-Qing Qu
- 1] Carnegie Institution for Science, 260 Panama Street, Stanford, California 94305, USA [2] Key Laboratory of Plant and Soil Interactions, College of Resources and Environmental Sciences, China Agricultural University, 100193 Beijing, China
| | - Clay J Carter
- 1] Department of Biology, University of Minnesota Duluth, Duluth, Minnesota 55812, USA [2] Department of Plant Biology, University of Minnesota, St Paul, Minnesota 55108, USA
| | - Ian T Baldwin
- Max Planck Institute for Chemical Ecology, Jena D-07745, Germany
| | - Wolf B Frommer
- 1] Department of Biology, Stanford University, Stanford, California 94305, USA [2] Carnegie Institution for Science, 260 Panama Street, Stanford, California 94305, USA
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37
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Abstract
The phloem is the long-distance solute-conducting tissue of plants. The observation of phloem cells is particularly challenging for several reasons and many recent advances in microscopy are, therefore, especially beneficial for the study of phloem anatomy and physiology. This review will give an overview of the imaging techniques that have been used for studying different aspects of phloem biology. It will also highlight some new imaging techniques that have emerged in recent years that will certainly advance our knowledge about phloem function.
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Affiliation(s)
- Elisabeth Truernit
- Department of Biology, ETH Zürich, Universitätsstrasse 2, 8092 Zürich, Switzerland
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38
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Srivastava G, Kayastha AM. Β-amylase from starchless seeds of Trigonella foenum-graecum and its localization in germinating seeds. PLoS One 2014; 9:e88697. [PMID: 24551136 PMCID: PMC3925156 DOI: 10.1371/journal.pone.0088697] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 01/09/2014] [Indexed: 11/25/2022] Open
Abstract
Fenugreek (Trigonella foenum-graecum) seeds do not contain starch as carbohydrate reserve. Synthesis of starch is initiated after germination. A β-amylase from ungerminated fenugreek seeds was purified to apparent electrophoretic homogeneity. The enzyme was purified 210 fold with specific activity of 732.59 units/mg. Mr of the denatured enzyme as determined from SDS-PAGE was 58 kD while that of native enzyme calculated from size exclusion chromatography was 56 kD. Furthermore, its identity was confirmed to be β-amylase from MALDI-TOF analysis. The optimum pH and temperature was found to be 5.0 and 50°C, respectively. Starch was hydrolyzed at highest rate and enzyme showed a Km of 1.58 mg/mL with it. Antibodies against purified Fenugreek β-amylase were generated in rabbits. These antibodies were used for localization of enzyme in the cotyledon during different stages of germination using fluorescence and confocal microscopy. Fenugreek β-amylase was found to be the major starch degrading enzyme depending on the high amount of enzyme present as compared to α-amylase and also its localization at the periphery of amyloplasts. A new finding in terms of its association with protophloem was observed. Thus, this enzyme appears to be important for germination of seeds.
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Affiliation(s)
- Garima Srivastava
- School of Biotechnology, Faculty of Science, Banaras Hindu University, Varanasi, India
| | - Arvind M. Kayastha
- School of Biotechnology, Faculty of Science, Banaras Hindu University, Varanasi, India
- * E-mail:
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39
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Furuta KM, Hellmann E, Helariutta Y. Molecular control of cell specification and cell differentiation during procambial development. ANNUAL REVIEW OF PLANT BIOLOGY 2014; 65:607-38. [PMID: 24579995 DOI: 10.1146/annurev-arplant-050213-040306] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Land plants develop vascular tissues that enable the long-distance transport of water and nutrients in xylem and phloem, provide mechanical support for their vertical growth, and produce cells in radial growth. Vascular tissues are produced in many parts of the plant and during different developmental stages. Early vascular development is focused in procambial meristems, and in some species it continues during the secondary phase of plant development in cambial meristems. In this review, we highlight recent progress in understanding procambial development. This involves the analysis of stem cell-like properties of procambial tissues, specification of xylem and phloem, and differentiation of the conductive tissues. Several major plant hormones, small-RNA species, and transcriptional networks play a role in vascular development. We describe current approaches to integrating these networks as well as their potential role in explaining the diversity and evolution of plant vascular systems.
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Affiliation(s)
- Kaori Miyashima Furuta
- Institute of Biotechnology and Department of Biology and Environmental Sciences, University of Helsinki, Helsinki FIN-00014, Finland; , ,
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40
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Lucas WJ, Groover A, Lichtenberger R, Furuta K, Yadav SR, Helariutta Y, He XQ, Fukuda H, Kang J, Brady SM, Patrick JW, Sperry J, Yoshida A, López-Millán AF, Grusak MA, Kachroo P. The plant vascular system: evolution, development and functions. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:294-388. [PMID: 23462277 DOI: 10.1111/jipb.12041] [Citation(s) in RCA: 400] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The emergence of the tracheophyte-based vascular system of land plants had major impacts on the evolution of terrestrial biology, in general, through its role in facilitating the development of plants with increased stature, photosynthetic output, and ability to colonize a greatly expanded range of environmental habitats. Recently, considerable progress has been made in terms of our understanding of the developmental and physiological programs involved in the formation and function of the plant vascular system. In this review, we first examine the evolutionary events that gave rise to the tracheophytes, followed by analysis of the genetic and hormonal networks that cooperate to orchestrate vascular development in the gymnosperms and angiosperms. The two essential functions performed by the vascular system, namely the delivery of resources (water, essential mineral nutrients, sugars and amino acids) to the various plant organs and provision of mechanical support are next discussed. Here, we focus on critical questions relating to structural and physiological properties controlling the delivery of material through the xylem and phloem. Recent discoveries into the role of the vascular system as an effective long-distance communication system are next assessed in terms of the coordination of developmental, physiological and defense-related processes, at the whole-plant level. A concerted effort has been made to integrate all these new findings into a comprehensive picture of the state-of-the-art in the area of plant vascular biology. Finally, areas important for future research are highlighted in terms of their likely contribution both to basic knowledge and applications to primary industry.
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Affiliation(s)
- William J Lucas
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, CA 95616, USA.
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41
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Truernit E, Bauby H, Belcram K, Barthélémy J, Palauqui JC. OCTOPUS, a polarly localised membrane-associated protein, regulates phloem differentiation entry in Arabidopsis thaliana. Development 2012; 139:1306-15. [DOI: 10.1242/dev.072629] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Vascular development is embedded into the developmental context of plant organ differentiation and can be divided into the consecutive phases of vascular patterning and differentiation of specific vascular cell types (phloem and xylem). To date, only very few genetic determinants of phloem development are known. Here, we identify OCTOPUS (OPS) as a potentiator of phloem differentiation. OPS is a polarly localised membrane-associated protein that is initially expressed in provascular cells, and upon vascular cell type specification becomes restricted to the phloem cell lineage. OPS mutants display a reduction of cotyledon vascular pattern complexity and discontinuous phloem differentiation, whereas OPS overexpressers show accelerated progress of cotyledon vascular patterning and phloem differentiation. We propose that OPS participates in vascular differentiation by interpreting longitudinal signals that lead to the transformation of vascular initials into differentiating protophloem cells.
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Affiliation(s)
- Elisabeth Truernit
- INRA, UMR1318, Institut Jean-Pierre Bourgin, RD10, 78000 Versailles, France
| | - Hélène Bauby
- INRA, UMR1318, Institut Jean-Pierre Bourgin, RD10, 78000 Versailles, France
| | - Katia Belcram
- INRA, UMR1318, Institut Jean-Pierre Bourgin, RD10, 78000 Versailles, France
| | - Julien Barthélémy
- INRA, UMR1318, Institut Jean-Pierre Bourgin, RD10, 78000 Versailles, France
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42
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Vázquez-Lobo A, Roujol D, Zuñiga-Sánchez E, Albenne C, Piñero D, Gamboa de Buen A, Jamet E. The highly conserved spermatophyte cell wall DUF642 protein family: phylogeny and first evidence of interaction with cell wall polysaccharides in vitro. Mol Phylogenet Evol 2012; 63:510-20. [PMID: 22361214 DOI: 10.1016/j.ympev.2012.02.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 01/31/2012] [Accepted: 02/01/2012] [Indexed: 12/27/2022]
Abstract
The evolution of spermatophyte plants involved fundamental changes in cell wall structure and function which resulted from diversification of carbohydrates and proteins. Cell wall proteomic analyses identified a novel family of proteins of yet unknown function, the DUF642 (Domain of Unknown Function 642) proteins. To investigate the evolution of the DUF642 gene family, 154 gene sequences from 24 plant species were analyzed, and phylogenetic inferences were conducted using the Maximum Likelihood and Bayesian Inference methods. Orthologous genes were detected in spermatophyte species and absent in non-seed known plant genomes. Protein sequences shared conserved motifs that defined the signature of the family. Distribution of conserved motifs indicated an ancestral intragenic duplication event. Gene phylogeny documented paleoduplication events originating three or four clades, depending on root position. When based on mid-point rooting, it retrieved four monophyletic clades: A, B, C, and D. A glycosylphosphatidylinositol (GPI)-anchor site and one or two galactose-binding domains-like (GBDLs) could be predicted for some DUF642 proteins. The B, C, and D clades grouped the predicted GPI-anchored proteins. First evidence of in vitro interaction of a DUF642 protein with a cell wall polysaccharide fraction is provided. A competition assay with cellulose prevented this interaction. The degree of diversification and the conservation of the family suggested that DUF642 proteins are key components in seed plant evolution.
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Affiliation(s)
- Alejandra Vázquez-Lobo
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico
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43
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Ingram P, Dettmer J, Helariutta Y, Malamy JE. Arabidopsis Lateral Root Development 3 is essential for early phloem development and function, and hence for normal root system development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 68:455-467. [PMID: 21749503 DOI: 10.1111/j.1365-313x.2011.04700.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have identified a gene, Lateral Root Development 3 (LRD3), that is important for maintaining a balance between primary and lateral root growth. The lrd3 mutant has decreased primary root growth and increased lateral root growth. We determined that the LRD3 gene encodes a LIM-domain protein of unknown function. LRD3 is expressed only in the phloem companion cells, which suggested a role in phloem function. Indeed, while phloem loading and export from the shoot appear to be normal, delivery of phloem to the primary root tip is limited severely in young seedlings. Abnormalities in phloem morphology in these seedlings indicate that LRD3 is essential for correct early phloem development. There is a subsequent spontaneous recovery of normal phloem morphology, which is correlated tightly with increased phloem delivery and growth of the primary root. The LRD3 gene is one of very few genes described to affect phloem development, and the only one that is specific to early phloem development. Continuous growth on auxin also leads to recovery of phloem development and function in lrd3, which demonstrates that auxin plays a key role in early phloem development. The root system architecture and the pattern of phloem allocation in the lrd3 root system suggested that there may be regulated mechanisms for selectively supporting certain lateral roots when the primary root is compromised. Therefore, this study provides new insights into phloem-mediated resource allocation and its effects on plant root system architecture.
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Affiliation(s)
- Paul Ingram
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 5812 S. Ellis Street, Chicago, IL 60637, USA
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Spatio-temporal sequence of cross-regulatory events in root meristem growth. Proc Natl Acad Sci U S A 2010; 107:22734-9. [PMID: 21149702 DOI: 10.1073/pnas.1014716108] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A central question in developmental biology is how multicellular organisms coordinate cell division and differentiation to determine organ size. In Arabidopsis roots, this balance is controlled by cytokinin-induced expression of SHORT HYPOCOTYL 2 (SHY2) in the so-called transition zone of the meristem, where SHY2 negatively regulates auxin response factors (ARFs) by protein-protein interaction. The resulting down-regulation of PIN-FORMED (PIN) auxin efflux carriers is considered the key event in promoting differentiation of meristematic cells. Here we show that this regulation involves additional, intermediary factors and is spatio-temporally constrained. We found that the described cytokinin-auxin crosstalk antagonizes BREVIS RADIX (BRX) activity in the developing protophloem. BRX is an auxin-responsive target of the prototypical ARF MONOPTEROS (MP), a key promoter of vascular development, and transiently enhances PIN3 expression to promote meristem growth in young roots. At later stages, cytokinin induction of SHY2 in the vascular transition zone restricts BRX expression to down-regulate PIN3 and thus limit meristem growth. Interestingly, proper SHY2 expression requires BRX, which could reflect feedback on the auxin responsiveness of SHY2 because BRX protein can directly interact with MP, likely acting as a cofactor. Thus, cross-regulatory antagonism between BRX and SHY2 could determine ARF activity in the protophloem. Our data suggest a model in which the regulatory interactions favor BRX expression in the early proximal meristem and SHY2 prevails because of supplementary cytokinin induction in the later distal meristem. The complex equilibrium of this regulatory module might represent a universal switch in the transition toward differentiation in various developmental contexts.
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Tian H, Baxter IR, Lahner B, Reinders A, Salt DE, Ward JM. Arabidopsis NPCC6/NaKR1 is a phloem mobile metal binding protein necessary for phloem function and root meristem maintenance. THE PLANT CELL 2010; 22:3963-79. [PMID: 21193571 PMCID: PMC3027173 DOI: 10.1105/tpc.110.080010] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Revised: 11/28/2010] [Accepted: 12/11/2010] [Indexed: 05/18/2023]
Abstract
SODIUM POTASSIUM ROOT DEFECTIVE1 (NaKR1; previously called NPCC6) encodes a soluble metal binding protein that is specifically expressed in companion cells of the phloem. The nakr1-1 mutant phenotype includes high Na(+), K(+), Rb(+), and starch accumulation in leaves, short roots, late flowering, and decreased long-distance transport of sucrose. Using traditional and DNA microarray-based deletion mapping, a 7-bp deletion was found in an exon of NaKR1 that introduced a premature stop codon. The mutant phenotypes were complemented by transformation with the native gene or NaKR1-GFP (green fluorescent protein) and NaKR1-β-glucuronidase fusions driven by the native promoter. NAKR1-GFP was mobile in the phloem; it moved from companion cells into sieve elements and into a previously undiscovered symplasmic domain in the root meristem. Grafting experiments revealed that the high Na(+) accumulation was due mainly to loss of NaKR1 function in the leaves. This supports a role for the phloem in recirculating Na(+) to the roots to limit Na(+) accumulation in leaves. The onset of root phenotypes coincided with NaKR1 expression after germination. The nakr1-1 short root phenotype was due primarily to a decreased cell division rate in the root meristem, indicating a role in root meristem maintenance for NaKR1 expression in the phloem.
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Affiliation(s)
- Hui Tian
- Department of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108
| | - Ivan R. Baxter
- Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907
| | - Brett Lahner
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47907
| | - Anke Reinders
- Department of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108
| | - David E. Salt
- Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47907
| | - John M. Ward
- Department of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108
- Address correspondence to
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Caño-Delgado A, Lee JY, Demura T. Regulatory Mechanisms for Specification and Patterning of Plant Vascular Tissues. Annu Rev Cell Dev Biol 2010; 26:605-37. [DOI: 10.1146/annurev-cellbio-100109-104107] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ana Caño-Delgado
- Molecular Genetics Department, Center for Research in Agricultural Genomics, Barcelona 08034, Spain;
| | - Ji-Young Lee
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853;
- Department of Plant Biology, Cornell University, Ithaca, NY 14853
| | - Taku Demura
- RIKEN Plant Science Center, Yokohama, Kanagawa 230-0045, Japan
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0136, Japan;
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Knoblauch M, Peters WS. Münch, morphology, microfluidics - our structural problem with the phloem. PLANT, CELL & ENVIRONMENT 2010; 33:1439-1452. [PMID: 20525003 DOI: 10.1111/j.1365-3040.2010.02177.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The sieve tubes of the phloem are enigmatic structures. Their role as channels for the distribution of assimilates was established in the 19th century, but their sensitivity to disturbations has hampered the elucidation of their transport mechanisms and its regulation ever since. Ernst Münch's classical monograph of 1930 is generally regarded as the first coherent theory of phloem transport, but the 'Münchian' pressure flow mechanism had been discussed already before the turn of the century. Münch's impact rather rested on his simple physical models of the phloem that visualized pressure flow in an intuitive way, and we argue that the downscaling of such models to realistic, low-Reynolds-number sizes will boost our understanding of phloem transport in this century just as Münch's models did in the previous one. However, biologically meaningful physical models that could be used to test predictions of the many existing mathematical models would have to be designed in analogy with natural phloem structures. Unfortunately, the study of phloem anatomy seems in decline, and we still lack basic quantitative data required for evaluating the plausibility of our theoretical deductions. In this review, we provide a subjective overview of unresolved problems in angiosperm phloem structure research within a functional context.
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Affiliation(s)
- Michael Knoblauch
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA.
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Yu NI, Lee SA, Lee MH, Heo JO, Chang KS, Lim J. Characterization of SHORT-ROOT function in the Arabidopsis root vascular system. Mol Cells 2010; 30:113-9. [PMID: 20680487 DOI: 10.1007/s10059-010-0095-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 04/19/2010] [Accepted: 04/22/2010] [Indexed: 11/29/2022] Open
Abstract
Development of the vascular tissues is a dynamic process that integrates extrinsic and intrinsic factors to control vascular tissue formation throughout the plant life cycle. During vascular tissue formation in Arabidopsis roots, radial and longitudinal signals, including nuclear factors and plant hormones, control the developmental processes involved in the specification, differentiation, and maintenance of the correct cell types. SHR, a GRAS transcription factor, has been known to regulate the specification of the stem cell niche and ground tissue identity in the root meristem in a non-cell-autonomous manner. However, the role of SHR in the root vasculature is relatively overlooked, despite localization of its mRNA and protein in the stele. Here, we investigated the role of SHR in the vascular system of the primary root using a reverse genetic approach and detailed phenotypic analysis. A novel, loss-of-function null mutant, shr-6, was isolated in the Columbia background, and vascular patterning was characterized in detail. Our results reveal that shr mutants have developmental defects in both protophloem and protoxylem elements. Our study also suggests that SHR plays a central role in the root vascular system to control patterning processes, possibly regulated by longitudinal and radial signals.
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Affiliation(s)
- Nan-Ie Yu
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, Korea
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Scacchi E, Osmont KS, Beuchat J, Salinas P, Navarrete-Gómez M, Trigueros M, Ferrándiz C, Hardtke CS. Dynamic, auxin-responsive plasma membrane-to-nucleus movement of Arabidopsis BRX. Development 2009; 136:2059-67. [DOI: 10.1242/dev.035444] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In Arabidopsis, interplay between nuclear auxin perception and trans-cellular polar auxin transport determines the transcriptional auxin response. In brevis radix (brx) mutants, this response is impaired, probably indirectly because of disturbed crosstalk between the auxin and brassinosteroid pathways. Here we provide evidence that BRX protein is plasma membrane-associated, but translocates to the nucleus upon auxin treatment to modulate cellular growth, possibly in conjunction with NGATHA class B3 domain-type transcription factors. Application of the polar auxin transport inhibitor naphthalene phthalamic acid (NPA) resulted in increased BRX abundance at the plasma membrane. Thus, nuclear translocation of BRX could depend on cellular auxin concentration or on auxin flux. Supporting this idea,NPA treatment of wild-type roots phenocopied the brx root meristem phenotype. Moreover, BRX is constitutively turned over by the proteasome pathway in the nucleus. However, a stabilized C-terminal BRX fragment significantly rescued the brx root growth phenotype and triggered a hypocotyl gain-of-function phenotype, similar to strong overexpressors of full length BRX. Therefore, although BRX activity is required in the nucleus,excess activity interferes with normal development. Finally, similar to the PIN-FORMED 1 (PIN1) auxin efflux carrier, BRX is polarly localized in vascular cells and subject to endocytic recycling. Expression of BRX under control of the PIN1 promoter fully rescued the brx short root phenotype, suggesting that the two genes act in the same tissues. Collectively, our results suggest that BRX might provide a contextual readout to synchronize cellular growth with the auxin concentration gradient across the root tip.
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Affiliation(s)
- Emanuele Scacchi
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Karen S. Osmont
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Julien Beuchat
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Paula Salinas
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | | | - Marina Trigueros
- Instituto de Biología Molecular y Celular de Plantas, UPV-CSIC, 46022 Valencia, Spain
| | - Cristina Ferrándiz
- Instituto de Biología Molecular y Celular de Plantas, UPV-CSIC, 46022 Valencia, Spain
| | - Christian S. Hardtke
- Department of Plant Molecular Biology, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
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