1
|
Bourdon M, Lyczakowski JJ, Cresswell R, Amsbury S, Vilaplana F, Le Guen MJ, Follain N, Wightman R, Su C, Alatorre-Cobos F, Ritter M, Liszka A, Terrett OM, Yadav SR, Vatén A, Nieminen K, Eswaran G, Alonso-Serra J, Müller KH, Iuga D, Miskolczi PC, Kalmbach L, Otero S, Mähönen AP, Bhalerao R, Bulone V, Mansfield SD, Hill S, Burgert I, Beaugrand J, Benitez-Alfonso Y, Dupree R, Dupree P, Helariutta Y. Ectopic callose deposition into woody biomass modulates the nano-architecture of macrofibrils. NATURE PLANTS 2023; 9:1530-1546. [PMID: 37666966 PMCID: PMC10505557 DOI: 10.1038/s41477-023-01459-0] [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: 10/25/2022] [Accepted: 06/14/2023] [Indexed: 09/06/2023]
Abstract
Plant biomass plays an increasingly important role in the circular bioeconomy, replacing non-renewable fossil resources. Genetic engineering of this lignocellulosic biomass could benefit biorefinery transformation chains by lowering economic and technological barriers to industrial processing. However, previous efforts have mostly targeted the major constituents of woody biomass: cellulose, hemicellulose and lignin. Here we report the engineering of wood structure through the introduction of callose, a polysaccharide novel to most secondary cell walls. Our multiscale analysis of genetically engineered poplar trees shows that callose deposition modulates cell wall porosity, water and lignin contents and increases the lignin-cellulose distance, ultimately resulting in substantially decreased biomass recalcitrance. We provide a model of the wood cell wall nano-architecture engineered to accommodate the hydrated callose inclusions. Ectopic polymer introduction into biomass manifests in new physico-chemical properties and offers new avenues when considering lignocellulose engineering.
Collapse
Affiliation(s)
- Matthieu Bourdon
- The Sainsbury Laboratory, University of Cambridge, Cambridge, UK.
- Friedrich Miescher Institute for Biomedical Research (FMI), Basel, Switzerland.
| | - Jan J Lyczakowski
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | | | - Sam Amsbury
- Centre for Plant Science, Faculty of Biological Sciences, University of Leeds, Leeds, UK
- Plants, Photosynthesis and Soil, School of Biosciences, The University of Sheffield, Sheffield, UK
| | - Francisco Vilaplana
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, Stockholm, Sweden
- Wallenberg Wood Science Centre (WWSC), KTH Royal Institute of Technology, Stockholm, Sweden
| | | | - Nadège Follain
- Normandie Université, UNIROUEN Normandie, INSA Rouen, CNRS, PBS, Rouen, France
| | - Raymond Wightman
- The Sainsbury Laboratory, University of Cambridge, Cambridge, UK
| | - Chang Su
- Wood Development Group, University of Helsinki, Helsinki, Finland
| | - Fulgencio Alatorre-Cobos
- The Sainsbury Laboratory, University of Cambridge, Cambridge, UK
- Conacyt-Unidad de Bioquimica y Biologia Molecular de Plantas, Centro de Investigación Científica de Yucatán, Mérida, Mexico
| | - Maximilian Ritter
- Wood Materials Science, Institute for Building Materials, ETH Zürich, Zürich, Switzerland
- Empa Wood Tec, Cellulose and Wood Materials Laboratory, Dübendorf, Switzerland
| | - Aleksandra Liszka
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
- Doctoral School of Exact and Natural Sciences, Jagiellonian University, Krakow, Poland
| | - Oliver M Terrett
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Shri Ram Yadav
- Wood Development Group, University of Helsinki, Helsinki, Finland
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India
| | - Anne Vatén
- Wood Development Group, University of Helsinki, Helsinki, Finland
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences and Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
- Stomatal Development and Plasticity group, University of Helsinki, Helsinki, Finland
| | - Kaisa Nieminen
- Wood Development Group, University of Helsinki, Helsinki, Finland
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences and Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
- Production systems / Tree Breeding Department, Natural Resources Institute Finland (Luke), Helsinki, Finland
| | - Gugan Eswaran
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences and Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
| | - Juan Alonso-Serra
- Wood Development Group, University of Helsinki, Helsinki, Finland
- UMR 5667 Reproduction et Développement Des Plantes, ENS de Lyon, France
| | - Karin H Müller
- Cambridge Advanced Imaging Centre, Department of Physiology, Development and Neuroscience, Cambridge, UK
| | - Dinu Iuga
- Department of Physics, University of Warwick, Coventry, UK
| | - Pal Csaba Miskolczi
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Lothar Kalmbach
- The Sainsbury Laboratory, University of Cambridge, Cambridge, UK
- Molecular Plant Physiology, Institute of Biology II, University of Freiburg, Freiburg, Germany
| | - Sofia Otero
- The Sainsbury Laboratory, University of Cambridge, Cambridge, UK
- Science and Technology Office of the Congress of Deputies, Madrid, Spain
| | - Ari Pekka Mähönen
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences and Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
| | - Rishikesh Bhalerao
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Vincent Bulone
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, Stockholm, Sweden
- College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, Australia
| | - Shawn D Mansfield
- Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | - Stefan Hill
- Scion, Te Papa Tipu Innovation Park, Rotorua, New Zealand
| | - Ingo Burgert
- Wood Materials Science, Institute for Building Materials, ETH Zürich, Zürich, Switzerland
- Empa Wood Tec, Cellulose and Wood Materials Laboratory, Dübendorf, Switzerland
| | - Johnny Beaugrand
- Biopolymères Interactions Assemblages (BIA), INRA, Nantes, France
| | - Yoselin Benitez-Alfonso
- The Centre for Plant Science, The Bragg Centre, The Astbury Centre, University of Leeds, Leeds, UK
| | - Ray Dupree
- Department of Physics, University of Warwick, Coventry, UK
| | - Paul Dupree
- Department of Biochemistry, University of Cambridge, Cambridge, UK.
| | - Ykä Helariutta
- The Sainsbury Laboratory, University of Cambridge, Cambridge, UK.
- Wood Development Group, University of Helsinki, Helsinki, Finland.
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences and Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland.
| |
Collapse
|
2
|
Tamura T, Endo H, Suzuki A, Sato Y, Kato K, Ohtani M, Yamaguchi M, Demura T. Affinity-based high-resolution analysis of DNA binding by VASCULAR-RELATED NAC-DOMAIN7 via fluorescence correlation spectroscopy. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 100:298-313. [PMID: 31313414 DOI: 10.1111/tpj.14443] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/30/2019] [Accepted: 06/11/2019] [Indexed: 06/10/2023]
Abstract
VASCULAR-RELATED NAC-DOMAIN7 (VND7) is the master transcription factor for vessel element differentiation in Arabidopsis thaliana. To identify the cis-acting sequence(s) bound by VND7, we employed fluorescence correlation spectroscopy (FCS) to find VND7-DNA interactions quantitatively. This identified an 18-bp sequence from the promoter of XYLEM CYSTEINE PEPTIDASE1 (XCP1), a direct target of VND7. A quantitative assay for binding affinity between VND7 and the 18-bp sequence revealed the core nucleotides contributing to specific binding between VND7 and the 18-bp sequence. Moreover, by combining the systematic evolution of ligands by exponential enrichment (SELEX) technique with known consensus sequences, we defined a motif termed the Ideal Core Structure for binding by VND7 (ICSV). We also used FCS to search for VND7 binding sequences in the promoter regions of other direct targets. Taking these data together, we proposed that VND7 preferentially binds to the ICSV sequence. Additionally, we found that substitutions among the core nucleotides affected transcriptional regulation by VND7 in vivo, indicating that the core nucleotides contribute to vessel-element-specific gene expression. Furthermore, our results demonstrate that FCS is a powerful tool for unveiling the DNA-binding properties of transcription factors.
Collapse
Affiliation(s)
- Taizo Tamura
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan
| | - Hitoshi Endo
- Institute of Transformative Bio-Molecules, Nagoya University, Nagoya, Aichi, 464-8602, Japan
| | - Atsunobu Suzuki
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan
| | - Yutaka Sato
- Genetic Strains Research Center, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Ko Kato
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan
| | - Misato Ohtani
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-8562, Japan
| | - Masatoshi Yamaguchi
- Graduate School of Science and Engineering, Saitama University, Saitama, Saitama, 338-8570, Japan
| | - Taku Demura
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan
| |
Collapse
|
3
|
Machin FQ, Beckers M, Tian X, Fairnie A, Cheng T, Scheible WR, Doerner P. Inducible reporter/driver lines for the Arabidopsis root with intrinsic reporting of activity state. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:153-164. [PMID: 30548978 DOI: 10.1111/tpj.14192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/26/2018] [Accepted: 11/27/2018] [Indexed: 06/09/2023]
Abstract
Cell-, tissue- or organ-specific inducible expression systems are powerful tools for functional analysis of changes to the pattern, level or timing of gene expression. However, plant researchers lack standardised reagents that promote reproducibility across the community. Here, we report the development and functional testing of a Gateway-based system for quantitatively, spatially and temporally controlling inducible gene expression in Arabidopsis that overcomes several drawbacks of the legacy systems. We used this modular driver/effector system with intrinsic reporting of spatio-temporal promoter activity to generate 18 well-characterised homozygous transformed lines showing the expected expression patterns specific for the major cell types of the Arabidopsis root; seed and plasmid vectors are available through the Arabidopsis stock centre. The system's tight regulation was validated by assessing the effects of diphtheria toxin A chain expression. We assessed the utility of Production of Anthocyanin Pigment 1 (PAP1) as an encoded effector mediating cell-autonomous marks. With this shared resource of characterised reference driver lines, which can be expanded with additional promoters and the use of other fluorescent proteins, we aim to contribute towards enhancing reproducibility of qualitative and quantitative analyses.
Collapse
Affiliation(s)
- Frank Qasim Machin
- Institute for Molecular Plant Science, University of Edinburgh, Edinburgh, UK
| | - Malin Beckers
- Institute for Molecular Plant Science, University of Edinburgh, Edinburgh, UK
| | - Xin Tian
- Institute for Molecular Plant Science, University of Edinburgh, Edinburgh, UK
| | - Alice Fairnie
- Institute for Molecular Plant Science, University of Edinburgh, Edinburgh, UK
| | - Teri Cheng
- Institute for Molecular Plant Science, University of Edinburgh, Edinburgh, UK
| | | | - Peter Doerner
- Institute for Molecular Plant Science, University of Edinburgh, Edinburgh, UK
- Max-Planck Institute of Molecular Plant Physiology, Science Park, Golm, Germany
- Laboratoire de Physiologie Cellulaire & Végétale, University Grenoble Alpes, CNRS, CEA, INRA, BIG-LPCV, 38000, Grenoble, France
| |
Collapse
|
4
|
Iakimova ET, Woltering EJ. Xylogenesis in zinnia (Zinnia elegans) cell cultures: unravelling the regulatory steps in a complex developmental programmed cell death event. PLANTA 2017; 245:681-705. [PMID: 28194564 PMCID: PMC5357506 DOI: 10.1007/s00425-017-2656-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 01/27/2017] [Indexed: 05/20/2023]
Abstract
MAIN CONCLUSION Physiological and molecular studies support the view that xylogenesis can largely be determined as a specific form of vacuolar programmed cell death (PCD). The studies in xylogenic zinnia cell culture have led to many breakthroughs in xylogenesis research and provided a background for investigations in other experimental models in vitro and in planta . This review discusses the most essential earlier and recent findings on the regulation of xylem elements differentiation and PCD in zinnia and other xylogenic systems. Xylogenesis (the formation of water conducting vascular tissue) is a paradigm of plant developmental PCD. The xylem vessels are composed of fused tracheary elements (TEs)-dead, hollow cells with patterned lignified secondary cell walls. They result from the differentiation of the procambium and cambium cells and undergo cell death to become functional post-mortem. The TE differentiation proceeds through a well-coordinated sequence of events in which differentiation and the programmed cellular demise are intimately connected. For years a classical experimental model for studies on xylogenesis was the xylogenic zinnia (Zinnia elegans) cell culture derived from leaf mesophyll cells that, upon induction by cytokinin and auxin, transdifferentiate into TEs. This cell system has been proven very efficient for investigations on the regulatory components of xylem differentiation which has led to many discoveries on the mechanisms of xylogenesis. The knowledge gained from this system has potentiated studies in other xylogenic cultures in vitro and in planta. The present review summarises the previous and latest findings on the hormonal and biochemical signalling, metabolic pathways and molecular and gene determinants underlying the regulation of xylem vessels differentiation in zinnia cell culture. Highlighted are breakthroughs achieved through the use of xylogenic systems from other species and newly introduced tools and analytical approaches to study the processes. The mutual dependence between PCD signalling and the differentiation cascade in the program of TE development is discussed.
Collapse
Affiliation(s)
| | - Ernst J Woltering
- Wageningen University and Research, Food and Biobased Research, P.O. Box 17, 6700 AA, Wageningen, The Netherlands.
- Wageningen University, Horticulture and Product Physiology, P.O. Box 630, 6700 AP, Wageningen, The Netherlands.
| |
Collapse
|
5
|
Chemical control of xylem differentiation by thermospermine, xylemin, and auxin. Sci Rep 2016; 6:21487. [PMID: 26879262 PMCID: PMC4754900 DOI: 10.1038/srep21487] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/25/2016] [Indexed: 12/14/2022] Open
Abstract
The xylem conducts water and minerals from the root to the shoot and provides mechanical strength to the plant body. The vascular precursor cells of the procambium differentiate to form continuous vascular strands, from which xylem and phloem cells are generated in the proper spatiotemporal pattern. Procambium formation and xylem differentiation are directed by auxin. In angiosperms, thermospermine, a structural isomer of spermine, suppresses xylem differentiation by limiting auxin signalling. However, the process of auxin-inducible xylem differentiation has not been fully elucidated and remains difficult to manipulate. Here, we found that an antagonist of spermidine can act as an inhibitor of thermospermine biosynthesis and results in excessive xylem differentiation, which is a phenocopy of a thermospermine-deficient mutant acaulis5 in Arabidopsis thaliana. We named this compound xylemin owing to its xylem-inducing effect. Application of a combination of xylemin and thermospermine to wild-type seedlings negates the effect of xylemin, whereas co-treatment with xylemin and a synthetic proauxin, which undergoes hydrolysis to release active auxin, has a synergistic inductive effect on xylem differentiation. Thus, xylemin may serve as a useful transformative chemical tool not only for the study of thermospermine function in various plant species but also for the control of xylem induction and woody biomass production.
Collapse
|
6
|
Mulisch M, Asp T, Krupinska K, Hollmann J, Holm PB. The Tr-cp 14 cysteine protease in white clover (Trifolium repens) is localized to the endoplasmic reticulum and is associated with programmed cell death during development of tracheary elements. PROTOPLASMA 2013; 250:623-9. [PMID: 22707085 DOI: 10.1007/s00709-012-0427-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 06/03/2012] [Indexed: 05/08/2023]
Abstract
Cysteine proteases are known to be associated with programmed cell death, developmental senescence and some types of pathogen and stress-induced responses. In the present study, we have characterized the cysteine protease Tr-cp 14 in white clover (Trifolium repens). Tr-cp 14 belongs to the C1A family of cysteine proteases with homology to XCP1 and XCP2 from Arabidopsis thaliana and p48h-17 from Zinnia elegans, which previously have been reported to be associated with tracheary element differentiation. The proform as well as the processed form of the protein was detected in petioles, flowers and leaves, but the processed form was more abundant in leaves and petioles than in flowers. The Tr-cp 14 protein was localized to differentiating tracheary elements within the xylem, indicating that the cysteine protease is involved in protein re-mobilization during tracheary element differentiation. Immunogold studies suggest that the protease prior to the burst of the vacuole was associated to the ER cisternae. After disruption of the tonoplast, it was found in the cytoplasm, and, in later stages, associated with disintegrating material dispersed throughout the cell.
Collapse
Affiliation(s)
- Maria Mulisch
- Institute of Botany and Central Microscopy, Christian-Albrechts-University Kiel, Olshausenstrasse 40, 24098, Kiel, Germany
| | | | | | | | | |
Collapse
|
7
|
Jiang Y, Zeng B, Zhao H, Zhang M, Xie S, Lai J. Genome-wide transcription factor gene prediction and their expressional tissue-specificities in maize. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2012; 54:616-30. [PMID: 22862992 DOI: 10.1111/j.1744-7909.2012.01149.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Transcription factors (TFs) are important regulators of gene expression. To better understand TF-encoding genes in maize (Zea mays L.), a genome-wide TF prediction was performed using the updated B73 reference genome. A total of 2298 TF genes were identified, which can be classified into 56 families. The largest family, known as the MYB superfamily, comprises 322 MYB and MYB-related TF genes. The expression patterns of 2 014 (87.64%) TF genes were examined using RNA-seq data, which resulted in the identification of a subset of TFs that are specifically expressed in particular tissues (including root, shoot, leaf, ear, tassel and kernel). Similarly, 98 kernel-specific TF genes were further analyzed, and it was observed that 29 of the kernel-specific genes were preferentially expressed in the early kernel developmental stage, while 69 of the genes were expressed in the late kernel developmental stage. Identification of these TFs, particularly the tissue-specific ones, provides important information for the understanding of development and transcriptional regulation of maize.
Collapse
Affiliation(s)
- Yi Jiang
- State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, China
| | | | | | | | | | | |
Collapse
|
8
|
Zang QW, Wang CX, Li XY, Guo ZA, Jing RL, Zhao J, Chang XP. Isolation and characterization of a gene encoding a polyethylene glycol-induced cysteine protease in common wheat. J Biosci 2011; 35:379-88. [PMID: 20826947 DOI: 10.1007/s12038-010-0043-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Plant cysteine protease (CP) genes are induced by abiotic stresses such as drought, yet their functions remain largely unknown. We isolated the full-length cDNA encoding a Triticum aestivum CP gene, designated TaCP, from wheat by the rapid amplification of cDNA ends (RACE) method. Sequence analysis revealed that TaCP contains an open reading frame encoding a protein of 362 amino acids, which is 96% identical to barley cysteine protease HvSF42. The TaCP transcript level in wheat seedlings was upregulated during polyethylene glycol (PEG) stress, with a peak appearing around 12 h after treatment. TaCP expression level increased rapidly with NaCl treatment at 48 h. TaCP responded strongly to low temperature (4 degree C) treatment from 1 h post-treatment and reached a peak of about 40-fold at 72 h. However, it showed only a very slight response to abscisic acid (ABA). More than one copy of TaCP was present in each of the three genomes of hexaploid wheat and its diploid donors. TaCP fused with green fluorescent protein (GFP) was located in the plasma membrane of onion epidermis cells. Transgenic Arabidopsis plants overexpressing TaCP showed stronger drought tolerance and higher CP activity under water-stressed conditions than wild-type Arabidopsis plants. The results suggest that TaCP plays a role in tolerance to water deficit.
Collapse
Affiliation(s)
- Qing-Wei Zang
- The National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Crop Germplasm and Biotechnology, Ministry of Agriculture, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | | | | | | | | | | | | |
Collapse
|
9
|
Tsugeki R, Ditengou FA, Sumi Y, Teale W, Palme K, Okada K. NO VEIN mediates auxin-dependent specification and patterning in the Arabidopsis embryo, shoot, and root. THE PLANT CELL 2009; 21:3133-51. [PMID: 19880797 PMCID: PMC2782279 DOI: 10.1105/tpc.109.068841] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Local efflux-dependent auxin gradients and maxima mediate organ and tissue development in plants. Auxin efflux is regulated by dynamic expression and subcellular localization of the PIN auxin-efflux proteins, which appears to be established not only through a self-organizing auxin-mediated polarization mechanism, but also through other means, such as cell fate determination and auxin-independent mechanisms. Here, we show that the Arabidopsis thaliana NO VEIN (NOV) gene, encoding a novel, plant-specific nuclear factor, is required for leaf vascular development, cellular patterning and stem cell maintenance in the root meristem, as well as for cotyledon outgrowth and separation. nov mutations affect many aspects of auxin-dependent development without directly affecting auxin perception. NOV is required for provascular PIN1 expression and region-specific expression of PIN7 in leaf primordia, cell type-specific expression of PIN3, PIN4, and PIN7 in the root, and PIN2 polarity in the root cortex. NOV is specifically expressed in developing embryos, leaf primordia, and shoot and root apical meristems. Our data suggest that NOV function underlies cell fate decisions associated with auxin gradients and maxima, thus establishing cell type-specific PIN expression and polarity. We propose that NOV mediates the acquisition of competence to undergo auxin-dependent coordinated cell specification and patterning, thereby eliciting context-dependent auxin-mediated developmental responses.
Collapse
Affiliation(s)
- Ryuji Tsugeki
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
| | | | | | | | | | | |
Collapse
|
10
|
Ceserani T, Trofka A, Gandotra N, Nelson T. VH1/BRL2 receptor-like kinase interacts with vascular-specific adaptor proteins VIT and VIK to influence leaf venation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 57:1000-14. [PMID: 19000166 PMCID: PMC2793540 DOI: 10.1111/j.1365-313x.2008.03742.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
VH1/BRL2 is a receptor-like kinase of the BRI1 family with a role in vascular development. In developing Arabidopsis leaves it is expressed first in ground cells and then becomes restricted to provascular and procambial cells as venation forms. We isolated proteins interacting with the activated (phosphorylated) cytoplasmic domain of VH1/BRL2, and found that most belong to three processes: proteasome activity, vesicle traffic and intracellular signal transduction. Two adaptor proteins are included that we named VIT [VH1-interacting tetratricopeptide repeat (TPR)-containing protein] and VIK (VH1-interacting kinase), which are co-expressed in the same cells as VH1/BRL2 at two distinct time points in vein differentiation. Mutation of either adaptor or of VH1 results in vein pattern defects and in alterations in response to auxin and brassinosteroids. We propose that these two adaptors facilitate the diversification and amplification of a ligand signal perceived by VH1/BRL2 in multiple downstream pathways affecting venation.
Collapse
Affiliation(s)
- Teresa Ceserani
- Department of Molecular, Cellular & Developmental Biology Yale University P.O. Box 208104 New Haven, CT 06520-8104
| | - Anna Trofka
- Department of Molecular, Cellular & Developmental Biology Yale University P.O. Box 208104 New Haven, CT 06520-8104
| | - Neeru Gandotra
- Department of Molecular, Cellular & Developmental Biology Yale University P.O. Box 208104 New Haven, CT 06520-8104
| | - Timothy Nelson
- Department of Molecular, Cellular & Developmental Biology Yale University P.O. Box 208104 New Haven, CT 06520-8104
| |
Collapse
|
11
|
Soyano T, Thitamadee S, Machida Y, Chua NH. ASYMMETRIC LEAVES2-LIKE19/LATERAL ORGAN BOUNDARIES DOMAIN30 and ASL20/LBD18 regulate tracheary element differentiation in Arabidopsis. THE PLANT CELL 2008; 20:3359-73. [PMID: 19088331 PMCID: PMC2630433 DOI: 10.1105/tpc.108.061796] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2008] [Revised: 11/20/2008] [Accepted: 12/02/2008] [Indexed: 05/17/2023]
Abstract
ASYMMETRIC LEAVES2 (AS2)/LATERAL ORGAN BOUNDARIES DOMAIN (LBD) family proteins are plant-specific nuclear proteins, and genes encoding several family members have been implicated in plant development. We investigated the function of two members of the Arabidopsis thaliana AS2/LBD family, AS2-LIKE19 (ASL19)/LBD30 and ASL20/LBD18, which encode homologous proteins. Both ASL19 and ASL20 were expressed in immature tracheary elements (TEs), and the expression was dependent on VASCULAR-RELATED NAC-DOMAIN PROTEIN6 (VND6) and VND7, which are transcription factors required for TE differentiation. Overexpression of ASL19 and ASL20 induced transdifferentiation of cells from nonvascular tissues into TE-like cells, similar to those induced upon VND6/7 overexpression. By contrast, aberrant TEs were formed when a cDNA encoding a fusion protein of ASL20 with an artificial repressor domain (ASL20-SRDX) was expressed from its native promoter. These results provide evidence that ASL proteins positively regulate TE differentiation. In transgenic plants overexpressing both ASL19 and ASL20, the xylem-deficient phenotype caused by the expression of dominant-negative versions of VND6/7 proteins was not rescued. However, ectopic expression of VND7 was detected in plants overexpressing ASL20. Moreover, VND genes and their downstream targets were downregulated in ASL20-SRDX plants. Therefore, ASL20 appears to be involved in a positive feedback loop for VND7 expression that regulates TE differentiation-related genes.
Collapse
Affiliation(s)
- Takashi Soyano
- Laboratory of Plant Molecular Biology, The Rockefeller University, New York, New York 10065, USA
| | | | | | | |
Collapse
|
12
|
Yan L, Han J, Yang Q, Sun Y, Kang J, Liu Z, Wu M. Isolation and characterization of a cDNA encoding a papain-like cysteine protease from alfalfa. DNA SEQUENCE : THE JOURNAL OF DNA SEQUENCING AND MAPPING 2008; 19:274-81. [PMID: 17896221 DOI: 10.1080/10253890701575166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Protein hydrolyzation is activated and involved in response to various stress signals. In the present study, a full-length cDNA, named MsCP1, encoding a papain-like cysteine protease was obtained by degenerated primers and 3'- and 5'-RACE from salt-tolerant alfalfa. The cDNA contained an open reading frame encoding a deduced protein of 350 amino acids with a putative N-terminal signal peptide, NPIR vacuole-sorting signal sequence and potential N-linked glycosylation sites. The deduced sequence showed a high similarity to deduced proteins from pea, tobacco, tomato and ryegrass. Fusion expression analysis in Escherichia coli showed that the putative eukaryotic signal peptide prevented its expression in prokaryotic system. The integration and transcript of the expression elements in transgenic tobacco plants were detected with Southern blot and RT-PCR analysis.
Collapse
Affiliation(s)
- Longfeng Yan
- Institute of Grassland Sciences, China Agricultural University, Beijing, People's Republic of China
| | | | | | | | | | | | | |
Collapse
|
13
|
Noll GA, Fontanellaz ME, Rüping B, Ashoub A, van Bel AJE, Fischer R, Knoblauch M, Prüfer D. Spatial and temporal regulation of the forisome gene for1 in the phloem during plant development. PLANT MOLECULAR BIOLOGY 2007; 65:285-94. [PMID: 17694275 DOI: 10.1007/s11103-007-9217-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Accepted: 07/23/2007] [Indexed: 05/04/2023]
Abstract
Forisomes are protein aggregates found uniquely in the sieve elements of Fabaceaen plants. Upon wounding they undergo a reversible, calcium-dependent conformational switch which enables them to act as cellular stopcocks. Forisomes begin to form in young sieve elements at an early stage of metaphloem differentiation. Genes encoding forisome components could therefore be useful as markers of early sieve element development. Here we present a comprehensive analysis of the developmental expression profile of for1, which encodes such a forisome component. The for1 gene is highly conserved among Fabaceaen species and appears to be unique to this phylogenetic lineage since no orthologous genes have been found in other plants, including Arabidopsis and rice. Even so, transgenic tobacco plants expressing reporter genes under the control of the for1 promoter display reporter activity exclusively in immature sieve elements. This suggests that the regulation of sieve element development is highly conserved even in plants where mature forisomes have not been detected. The promoter system could therefore provide a powerful tool for the detailed analysis of differentiation in metaphloem sieve elements in an unexpectedly broad range of plant species.
Collapse
Affiliation(s)
- Gundula A Noll
- Institut für Biochemie und Biotechnologie der Pflanzen der, Westfälischen Wilhelms-Universität Münster, Hindenburgplatz 55, 48143, Munster, Germany
| | | | | | | | | | | | | | | |
Collapse
|
14
|
Pyo H, Demura T, Fukuda H. TERE; a novel cis-element responsible for a coordinated expression of genes related to programmed cell death and secondary wall formation during differentiation of tracheary elements. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2007; 51:955-65. [PMID: 17683474 DOI: 10.1111/j.1365-313x.2007.03180.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The differentiation of water-conducting tracheary elements (TEs) is the result of the orchestrated construction of secondary wall structure, including lignification, and programmed cell death (PCD), including cellular autolysis. To understand the orchestrated regulation of differentiation of TEs, we investigated the regulatory mechanism of gene expression directing TE differentiation. Detailed loss-of-function and gain-of-function analyses of the ZCP4 (Zinniacysteine protease 4) promoter, which confers TE-specific expression, demonstrated that a novel 11-bp cis-element is necessary and sufficient for the immature TE-specific promoter activity. The 11-bp cis-element-like sequences were found in promoters of many Arabidopsis TE differentiation-related genes. A gain-of-function analysis with similar putative cis-elements from secondary wall formation or modification-related genes as well as PCD-related genes indicated that the cis-elements are also sufficient for TE-specific expression of genes. These results demonstrate that a common sequence, designated as the tracheary-element-regulating cis-element, confers TE-specific expression to both genes related to secondary wall formation or modification and PCD.
Collapse
Affiliation(s)
- Hyunjin Pyo
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | | | | |
Collapse
|
15
|
Konishi M, Yanagisawa S. Sequential activation of two Dof transcription factor gene promoters during vascular development in Arabidopsis thaliana. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2007; 45:623-9. [PMID: 17583520 DOI: 10.1016/j.plaphy.2007.05.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Accepted: 05/04/2007] [Indexed: 05/15/2023]
Abstract
Plant-specific Dof transcription factors play various roles in plants. We show the strictly regulated activity of two Dof gene promoters during procambium formation, an early process for vascular development, in Arabidopsis thaliana (L.) Heynh. The AtDof2.4 promoter was active in procambial cells of leaf primordia, roots and embryos, whereas the AtDof5.8 promoter activity was specifically detectable in the cells of prospective veins in leaf primordia of seedlings and cotyledons of developing embryos, and the vascular tissue of developing flower buds. The AtDof5.8 promoter but not the AtDof2.4 promoter showed strong activity in advance of perceptible procambium formation. AtDof2.4 and AtDof5.8 might function in the early but different processes for vascular development.
Collapse
Affiliation(s)
- Mineko Konishi
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | | |
Collapse
|
16
|
Bauby H, Divol F, Truernit E, Grandjean O, Palauqui JC. Protophloem differentiation in early Arabidopsis thaliana development. PLANT & CELL PHYSIOLOGY 2007; 48:97-109. [PMID: 17135286 DOI: 10.1093/pcp/pcl045] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
During Arabidopsis embryogenesis, procambial cells undergo coordinated, asymmetric cell divisions, giving rise to vascular precursor cells (protophloem and protoxylem precursors). After germination, these cells terminally differentiate into specialized conducting cells, referred to as protophloem and protoxylem cells. Few readily identifiable markers of the onset of specification and differentiation are available, hampering the molecular genetic analysis of protophloem development. Confocal microscopy was used to investigate the patterning and differentiation of phloem cells during early plant development. Longitudinal divisions of phloem initials allowed the identification of protophloem precursor cells and adjacent metaphloem initials along the length of the plant. During germination, protophloem differentiation was observed at two independent locations, in the cotyledons and the hypocotyl. In both locations, differentiation was concomitant with cell elongation. We identified five gene-trap lines (PD1-PD5) with marker gene expression in immature protophloem elements. The spatio-temporal marker expression pattern of the lines divides them into two groups. The early specification markers PD4 and PD5 were expressed in developing organs before procambium formation and then became restricted to phloem initial cells. The protophloem precursor markers PD1-PD3 were expressed in differentiating protophloem cells at different stages of their development. All markers were expressed transiently and iteratively during the differentiation of protophloem in newly formed organs. Flanking genes were identified for four out of five gene-trap insertion lines. The possible function of these genes with respect to phloem differentiation is discussed.
Collapse
Affiliation(s)
- Hélène Bauby
- INRA, Centre de Versailles, Institut Jean-Pierre Bourgin, Laboratoire de Biologie Cellulaire, Route de St-Cyr, 78026 Versailles cedex, France
| | | | | | | | | |
Collapse
|
17
|
Feugier FG, Iwasa Y. How canalization can make loops: A new model of reticulated leaf vascular pattern formation. J Theor Biol 2006; 243:235-44. [PMID: 16887150 DOI: 10.1016/j.jtbi.2006.05.022] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2006] [Revised: 05/25/2006] [Accepted: 05/25/2006] [Indexed: 11/21/2022]
Abstract
Formation of the vascular system in plant leaves can be explained by the canalization hypothesis which states that veins are formed in an initially homogeneous field by a self-organizing process between the plant hormone auxin and auxin carrier proteins. Previous models of canalization can generate vein patterns with branching but fail to generate vein patterns with closed loops. However, closed vein loops are commonly observed in plant leaves and are important in making them robust to herbivore attacks and physical damage. Here we propose a new model which generates a vein system with closed loops. We postulate that the "flux bifurcator" level is enhanced in cells with a high auxin flux and that it causes reallocation of auxin carriers toward neighbouring cells also having a high bifurcator level. This causes the auxin flux to bifurcate, allowing vein tips to attach to other veins creating vein loops. We explore several alternative functional forms for the flux bifurcator affecting the reallocation of efflux carriers and examine parameter dependence of the resulting vein pattern.
Collapse
Affiliation(s)
- François G Feugier
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan.
| | | |
Collapse
|
18
|
Mähönen AP, Bishopp A, Higuchi M, Nieminen KM, Kinoshita K, Törmäkangas K, Ikeda Y, Oka A, Kakimoto T, Helariutta Y. Cytokinin signaling and its inhibitor AHP6 regulate cell fate during vascular development. Science 2006; 311:94-8. [PMID: 16400151 DOI: 10.1126/science.1118875] [Citation(s) in RCA: 394] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The cell lineages that form the transporting tissues (xylem and phloem) and the intervening pluripotent procambial tissue originate from stem cells near the root tip. We demonstrate that in Arabidopsis, cytokinin phytohormones negatively regulate protoxylem specification. AHP6, an inhibitory pseudophosphotransfer protein, counteracts cytokinin signaling, allowing protoxylem formation. Conversely, cytokinin signaling negatively regulates the spatial domain of AHP6 expression. Thus, by controlling the identity of cell lineages, the reciprocal interaction of cytokinin signaling and its spatially specific modulator regulates proliferation and differentiation of cell lineages during vascular development, demonstrating a previously unrecognized regulatory circuit underlying meristem organization.
Collapse
Affiliation(s)
- Ari Pekka Mähönen
- Plant Molecular Biology Laboratory, Institute of Biotechnology, POB 56, FI-00014, University of Helsinki, Finland
| | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Yoshida S, Kuriyama H, Fukuda H. Inhibition of Transdifferentiation into Tracheary Elements by Polar Auxin Transport Inhibitors Through Intracellular Auxin Depletion. ACTA ACUST UNITED AC 2005; 46:2019-28. [PMID: 16230330 DOI: 10.1093/pcp/pci217] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Polar auxin transport is essential for the formation of continuous vascular strands in the plant body. To understand its mechanism, polar auxin transport inhibitors have often been used. However, the role of auxin in vascular differentiation at the unicellular level has remained elusive. Using a Zinnia elegans cell culture system, in which single mesophyll cells transdifferentiate into tracheary elements (TEs), we demonstrated that auxin transport inhibitors prevented TE differentiation and that high concentrations of 1-naphthaleneacetic acid (NAA) and IAA overcame the repression of TE differentiation. Measurements of NAA accumulation with 3H-labeled NAA in the presence or absence of 1-N-naphthylphthalamic acid (NPA) revealed enhanced NAA accumulation within the cell. In the NPA-treated cells, intracellular free NAA decreased, while its metabolites increased. Therefore, the polar auxin transport inhibitors may prevent auxin efflux and consequently promote NAA accumulation in Zinnia cells. The excess intracellular NAA may also activate NAA metabolism, resulting in a decrease in free NAA levels. This depletion of free NAA may prevent TE differentiation. The decreased auxin activity in NPA-treated cells was confirmed by the fact that the DR5 (a synthetic auxin-inducible promoter)-mediated expression of a reporter protein was suppressed in such cells. Gene expression analysis indicated that NPA suppressed TE differentiation at an early process of transdifferentiation into TEs. Based on these results, the inter-relationship between auxin and vascular cell development at a cellular level is discussed.
Collapse
Affiliation(s)
- Saiko Yoshida
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
| | | | | |
Collapse
|
20
|
Kubo M, Udagawa M, Nishikubo N, Horiguchi G, Yamaguchi M, Ito J, Mimura T, Fukuda H, Demura T. Transcription switches for protoxylem and metaxylem vessel formation. Genes Dev 2005; 19:1855-60. [PMID: 16103214 PMCID: PMC1186185 DOI: 10.1101/gad.1331305] [Citation(s) in RCA: 766] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Land plants evolved xylem vessels to conduct water and nutrients, and to support the plant. Microarray analysis with a newly established Arabidopsis in vitro xylem vessel element formation system and promoter analysis revealed the possible involvement of some plant-specific NAC-domain transcription factors in xylem formation. VASCULAR-RELATED NAC-DOMAIN6 (VND6) and VND7 can induce transdifferentiation of various cells into metaxylem- and protoxylem-like vessel elements, respectively, in Arabidopsis and poplar. A dominant repression of VND6 and VND7 specifically inhibits metaxylem and protoxylem vessel formation in roots, respectively. These findings suggest that these genes are transcription switches for plant metaxylem and protoxylem vessel formation.
Collapse
Affiliation(s)
- Minoru Kubo
- RIKEN Plant Science Center, Yokohama, Kanagawa, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Brembu T, Winge P, Bones AM. The small GTPase AtRAC2/ROP7 is specifically expressed during late stages of xylem differentiation in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2005; 56:2465-76. [PMID: 16061508 DOI: 10.1093/jxb/eri239] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The RAC/ROP family of small GTPases are central regulators of important cellular processes in plants. AtRAC2/ROP7 is an ancient member of the RAC/ROP gene family in Arabidopsis thaliana whose functions are generally unknown. In order to study the spatial expression pattern of the AtRAC2/ROP7 gene, transgenic plants expressing GUS or GFP under the control of the AtRAC2/ROP7 promoter were analysed. Functional analysis of AtRAC2/ROP7 was done using transgenic plants overexpressing wild-type and constitutively activated AtRAC2/ROP7 (Val15Gly), and an AtRAC2/ROP7T-DNA insertion mutant. The AtRAC2/ROP7 promoter directs a highly specific xylem-specific expression in the root, hypocotyl, stem, and leaves. The expression is developmentally limited to the late stages of xylem differentiation, and coincides with the formation of secondary cell walls. Leaf epidermal cells of transgenic plants overexpressing constitutively active AtRAC2/ROP7 exhibited highly impaired lobe formation, suggesting that AtRAC2/ROP7 is able to regulate polar cell expansion. Finally, GFP-AtRAC2/ROP7 fusion proteins were localized to the plasma membrane. The results indicate a role for AtRAC2/ROP7 in the development of secondary cell walls of xylem vessels.
Collapse
Affiliation(s)
- Tore Brembu
- Department of Biology, Section for Cell and Molecular Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | | | | |
Collapse
|
22
|
Koizumi K, Naramoto S, Sawa S, Yahara N, Ueda T, Nakano A, Sugiyama M, Fukuda H. VAN3 ARF-GAP-mediated vesicle transport is involved in leaf vascular network formation. Development 2005; 132:1699-711. [PMID: 15743878 DOI: 10.1242/dev.01716] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Within the leaf of an angiosperm, the vascular system is constructed in a complex network pattern called venation. The formation of this vein pattern has been widely studied as a paradigm of tissue pattern formation in plants. To elucidate the molecular mechanism controlling the vein patterning process, we previously isolated Arabidopsis mutants van1 to van7, which show a discontinuous vein pattern. Here we report the phenotypic analysis of the van3 mutant in relation to auxin signaling and polar transport, and the molecular characterization of the VAN3 gene and protein. Double mutant analyses with pin1, emb30-7/gn and mp, and physiological analyses using the auxin-inducible marker DR5::GUS and an auxin transport inhibitor indicated that VAN3 may be involved in auxin signal transduction, but not in polar auxin transport. Positional cloning identified VAN3 as a gene that encodes an adenosine diphosphate (ADP)-ribosylation factor-guanosine triphosphatase (GTPase) activating protein (ARF-GAP). It resembles animal ACAPs and contains four domains: a BAR (BIN/amphiphysin/RVS) domain, a pleckstrin homology (PH) domain, an ARF-GAP domain and an ankyrin (ANK)-repeat domain. Recombinant VAN3 protein showed GTPase-activating activity and a specific affinity for phosphatidylinositols. This protein can self-associate through the N-terminal BAR domain in the yeast two-hybrid system. Subcellular localization analysis by double staining for Venus-tagged VAN3 and several green-fluorescent-protein-tagged intracellular markers indicated that VAN3 is located in a subpopulation of the trans-Golgi network (TGN). Our results indicate that the expression of this gene is induced by auxin and positively regulated by VAN3 itself, and that a specific ACAP type of ARF-GAP functions in vein pattern formation by regulating auxin signaling via a TGN-mediated vesicle transport system.
Collapse
Affiliation(s)
- Koji Koizumi
- Department of Bioscience, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | | | | | | | | | | | | | | |
Collapse
|