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Liu B, Wang T, Liu L, Xiao D, Yang Y, Yuan L, Zhang A, Xu K, Liu S, Liu K, Chen L. MYB6/bHLH13-AbSUS2 involved in sugar metabolism regulates root hair initiation of Abies beshanzuensis. THE NEW PHYTOLOGIST 2023; 240:2386-2403. [PMID: 37817383 DOI: 10.1111/nph.19301] [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: 06/05/2023] [Accepted: 09/16/2023] [Indexed: 10/12/2023]
Abstract
Root hair is regarded as a pivotal complementary survival tactic for mycorrhizal plant like Abies beshanzuensis when symbiosis is disrupted. Relatively little is known about the mechanism underlying root hair morphogenesis in plant species that are strongly dependent on mycorrhizal symbiosis. Many of these species are endangered, and this knowledge is critical for ensuring their survival. Here, a MYB6/bHLH13-sucrose synthase 2 (AbSUS2) module was newly identified and characterized in A. beshanzuensis using bioinformatics, histochemistry, molecular biology, and transgenesis. Functional, expression pattern, and localization analysis showed that AbSUS2 participated in sucrose synthesis and was involved in root hair initiation in A. beshanzuensis. Additionally, the major enzymatic product of AbSUS2 was found to suppress root hair initiation in vitro. Our data further showed that a complex involving the transcription factors AbMYB6 and AbbHLH13 directly interacted with the promoter of AbSUS2 and strengthened its expression, thereby inhibiting root hair initiation in response to exogenous sucrose. Our findings offer novel insights into how root hair morphogenesis is regulated in mycorrhizal plants and also provide a new strategy for the preservation of endangered mycorrhizal plant species.
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Affiliation(s)
- Bin Liu
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Tingjin Wang
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Lingjuan Liu
- Longquan Preserve Center of Qianjiangyuan-Baishanzu National Park, Longquan, Zhejiang, 323714, China
| | - Duohong Xiao
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Yang Yang
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Lu Yuan
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Aijun Zhang
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Kexin Xu
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Shenglong Liu
- Longquan Preserve Center of Qianjiangyuan-Baishanzu National Park, Longquan, Zhejiang, 323714, China
| | - Ke Liu
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Liping Chen
- Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, Zhejiang, 310058, China
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2
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Hanlon MT, Vejchasarn P, Fonta JE, Schneider HM, McCouch SR, Brown KM. Genome wide association analysis of root hair traits in rice reveals novel genomic regions controlling epidermal cell differentiation. BMC PLANT BIOLOGY 2023; 23:6. [PMID: 36597029 PMCID: PMC9811729 DOI: 10.1186/s12870-022-04026-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 12/22/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND Genome wide association (GWA) studies demonstrate linkages between genetic variants and traits of interest. Here, we tested associations between single nucleotide polymorphisms (SNPs) in rice (Oryza sativa) and two root hair traits, root hair length (RHL) and root hair density (RHD). Root hairs are outgrowths of single cells on the root epidermis that aid in nutrient and water acquisition and have also served as a model system to study cell differentiation and tip growth. Using lines from the Rice Diversity Panel-1, we explored the diversity of root hair length and density across four subpopulations of rice (aus, indica, temperate japonica, and tropical japonica). GWA analysis was completed using the high-density rice array (HDRA) and the rice reference panel (RICE-RP) SNP sets. RESULTS We identified 18 genomic regions related to root hair traits, 14 of which related to RHD and four to RHL. No genomic regions were significantly associated with both traits. Two regions overlapped with previously identified quantitative trait loci (QTL) associated with root hair density in rice. We identified candidate genes in these regions and present those with previously published expression data relevant to root hair development. We re-phenotyped a subset of lines with extreme RHD phenotypes and found that the variation in RHD was due to differences in cell differentiation, not cell size, indicating genes in an associated genomic region may influence root hair cell fate. The candidate genes that we identified showed little overlap with previously characterized genes in rice and Arabidopsis. CONCLUSIONS Root hair length and density are quantitative traits with complex and independent genetic control in rice. The genomic regions described here could be used as the basis for QTL development and further analysis of the genetic control of root hair length and density. We present a list of candidate genes involved in root hair formation and growth in rice, many of which have not been previously identified as having a relation to root hair growth. Since little is known about root hair growth in grasses, these provide a guide for further research and crop improvement.
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Affiliation(s)
- Meredith T Hanlon
- Department of Plant Science, The Pennsylvania State University, 102 Tyson Building, University Park, PA, 16802, USA
- Intercollege Graduate Degree Program in Plant Biology, Huck Institutes of the Life Sciences, Penn State University, University Park, PA, 16802, USA
| | - Phanchita Vejchasarn
- Department of Plant Science, The Pennsylvania State University, 102 Tyson Building, University Park, PA, 16802, USA
- Rice Department, Ministry of Agriculture, Ubon Ratchathani Rice Research Center, Ubon Ratchathani, 34000, Thailand
| | - Jenna E Fonta
- Department of Plant Science, The Pennsylvania State University, 102 Tyson Building, University Park, PA, 16802, USA
- Intercollege Graduate Degree Program in Plant Biology, Huck Institutes of the Life Sciences, Penn State University, University Park, PA, 16802, USA
| | - Hannah M Schneider
- Department of Plant Science, The Pennsylvania State University, 102 Tyson Building, University Park, PA, 16802, USA
- Centre for Crop Systems Analysis, Wageningen University & Research, Wageningen, the Netherlands
| | - Susan R McCouch
- Section of Plant Breeding and Genetics, School of Integrated Plant Sciences, Cornell University, Ithaca, NY, 14853-1901, USA
- Biological Statistics and Computational Biology, Cornell University, Ithaca, NY, 14853-1901, USA
| | - Kathleen M Brown
- Department of Plant Science, The Pennsylvania State University, 102 Tyson Building, University Park, PA, 16802, USA.
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Rajendran S, Kim CM. OsCSLD1 Mediates NH 4+-Dependent Root Hair Growth Suppression and AMT1;2 Expression in Rice ( Oryza sativa L.). PLANTS (BASEL, SWITZERLAND) 2022; 11:3580. [PMID: 36559692 PMCID: PMC9788582 DOI: 10.3390/plants11243580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 12/07/2022] [Accepted: 12/13/2022] [Indexed: 06/17/2023]
Abstract
Root hairs play crucial roles in the roots, including nutrient uptake, water assimilation, and anchorage with soil, along with supporting rhizospheric microorganisms. In rice, ammonia uptake is mediated by a specialized ammonium transporter (AMT). AMT1;1, AMT1;2, and AMT1;3 have been extensively studied in relation to nitrogen signaling. Cellulose synthase-like D1 (CSLD1) is essential for cell expansion and is highly specific to root hair cells. csld1 mutants showed successful initiation but failed to elongate. However, when nitrogen was depleted, csld1 root hairs resumed elongation. Further experiments revealed that in the presence of ammonium (NH4+), csld1 roots failed to elongate. csld1 elongated normally in the presence of nitrate (NO3−). Expression analysis showed an increase in root hair-specific AMT1;2 expression in csld1. CSLD1 was positively co-expressed with AMT1;2 changing nitrogen concentration in the growth media. CSLD1 showed increased expression in the presence of both ammonium and nitrate. Methylammonium (MeA) treatment of CSLD1 overexpression lines suggests that CSLD1 does not directly participate in nitrogen transport. Further studies on the root hair elongation mutant sndp1 showed that nitrogen assimilation is unlikely to depend on root hair length. Therefore, these results suggest that CSLD1 is closely involved in nitrogen-dependent root hair elongation and regulation of AMT1;2 expression in rice roots.
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4
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Shibata M, Favero DS, Takebayashi R, Takebayashi A, Kawamura A, Rymen B, Hosokawa Y, Sugimoto K. Trihelix transcription factors GTL1 and DF1 prevent aberrant root hair formation in an excess nutrient condition. THE NEW PHYTOLOGIST 2022; 235:1426-1441. [PMID: 35713645 PMCID: PMC9544051 DOI: 10.1111/nph.18255] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
Root hair growth is tuned in response to the environment surrounding plants. While most previous studies focused on the enhancement of root hair growth during nutrient starvation, few studies investigated the root hair response in the presence of excess nutrients. We report that the post-embryonic growth of wild-type Arabidopsis plants is strongly suppressed with increasing nutrient availability, particularly in the case of root hair growth. We further used gene expression profiling to analyze how excess nutrient availability affects root hair growth, and found that RHD6 subfamily genes, which are positive regulators of root hair growth, are downregulated in this condition. However, defects in GTL1 and DF1, which are negative regulators of root hair growth, cause frail and swollen root hairs to form when excess nutrients are supplied. Additionally, we observed that the RHD6 subfamily genes are mis-expressed in gtl1-1 df1-1. Furthermore, overexpression of RSL4, an RHD6 subfamily gene, induces swollen root hairs in the face of a nutrient overload, while mutation of RSL4 in gtl1-1 df1-1 restore root hair swelling phenotype. In conclusion, our data suggest that GTL1 and DF1 prevent unnecessary root hair formation by repressing RSL4 under excess nutrient conditions.
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Affiliation(s)
| | - David S. Favero
- RIKEN Center for Sustainable Resource ScienceYokohama230‐0045Japan
| | - Ryu Takebayashi
- Division of Materials Science, Graduate School of Science and TechnologyNara Institute of Science and TechnologyIkoma630‐0192Japan
| | | | - Ayako Kawamura
- RIKEN Center for Sustainable Resource ScienceYokohama230‐0045Japan
| | - Bart Rymen
- RIKEN Center for Sustainable Resource ScienceYokohama230‐0045Japan
- KU Leuven Plant Institute (LPI)KU LeuvenKasteelpark Arenberg 31LeuvenB‐3001Belgium
| | - Yoichiroh Hosokawa
- Division of Materials Science, Graduate School of Science and TechnologyNara Institute of Science and TechnologyIkoma630‐0192Japan
| | - Keiko Sugimoto
- RIKEN Center for Sustainable Resource ScienceYokohama230‐0045Japan
- Department of Biological SciencesUniversity of TokyoTokyo119‐0033Japan
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5
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Dünser K, Schöller M, Rößling AK, Löfke C, Xiao N, Pařízková B, Melnik S, Rodriguez-Franco M, Stöger E, Novák O, Kleine-Vehn J. Endocytic trafficking promotes vacuolar enlargements for fast cell expansion rates in plants. eLife 2022; 11:75945. [PMID: 35686734 PMCID: PMC9187339 DOI: 10.7554/elife.75945] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 05/31/2022] [Indexed: 11/13/2022] Open
Abstract
The vacuole has a space-filling function, allowing a particularly rapid plant cell expansion with very little increase in cytosolic content (Löfke et al., 2015; Scheuring et al., 2016; Dünser et al., 2019). Despite its importance for cell size determination in plants, very little is known about the mechanisms that define vacuolar size. Here, we show that the cellular and vacuolar size expansions are coordinated. By developing a pharmacological tool, we enabled the investigation of membrane delivery to the vacuole during cellular expansion. Our data reveal that endocytic membrane sorting from the plasma membrane to the vacuole is enhanced in the course of rapid root cell expansion. While this ‘compromise’ mechanism may theoretically at first decelerate cell surface enlargements, it fuels vacuolar expansion and, thereby, ensures the coordinated augmentation of vacuolar occupancy in dynamically expanding plant cells.
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Affiliation(s)
- Kai Dünser
- Molecular Plant Physiology (MoPP), Faculty of Biology, University of Freiburg, Freiburg, Germany.,Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria.,Center for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, Freiburg, Germany
| | - Maria Schöller
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Ann-Kathrin Rößling
- Molecular Plant Physiology (MoPP), Faculty of Biology, University of Freiburg, Freiburg, Germany.,Center for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, Freiburg, Germany
| | - Christian Löfke
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Nannan Xiao
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Barbora Pařízková
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences and Faculty of Science of Palacký University, Olomouc, Czech Republic
| | - Stanislav Melnik
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | | | - Eva Stöger
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Ondřej Novák
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences and Faculty of Science of Palacký University, Olomouc, Czech Republic
| | - Jürgen Kleine-Vehn
- Molecular Plant Physiology (MoPP), Faculty of Biology, University of Freiburg, Freiburg, Germany.,Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria.,Center for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, Freiburg, Germany
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6
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Kohli PS, Maurya K, Thakur JK, Bhosale R, Giri J. Significance of root hairs in developing stress-resilient plants for sustainable crop production. PLANT, CELL & ENVIRONMENT 2022; 45:677-694. [PMID: 34854103 DOI: 10.1111/pce.14237] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 11/15/2021] [Accepted: 11/21/2021] [Indexed: 06/13/2023]
Abstract
Root hairs represent a beneficial agronomic trait to potentially reduce fertilizer and irrigation inputs. Over the past decades, research in the plant model Arabidopsis thaliana has provided insights into root hair development, the underlying genetic framework and the integration of environmental cues within this framework. Recent years have seen a paradigm shift, where studies are now highlighting conservation and diversification of root hair developmental programs in other plant species and the agronomic relevance of root hairs in a wider ecological context. In this review, we specifically discuss the molecular evolution of the RSL (RHD Six-Like) pathway that controls root hair development and growth in land plants. We also discuss how root hairs contribute to plant performance as an active physiological rooting structure by performing resource acquisition, providing anchorage and constructing the rhizosphere with desirable physical, chemical and biological properties. Finally, we outline future research directions that can help achieve the potential of root hairs in developing sustainable agroecosystems.
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Affiliation(s)
| | - Kanika Maurya
- National Institute of Plant Genome Research, New Delhi, India
| | - Jitendra K Thakur
- National Institute of Plant Genome Research, New Delhi, India
- International Centre of Genetic Engineering and Biotechnology, New Delhi, India
| | - Rahul Bhosale
- Future Food Beacon of Excellence and School of Biosciences, University of Nottingham, Nottingham, UK
| | - Jitender Giri
- National Institute of Plant Genome Research, New Delhi, India
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7
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Kang BH, Anderson CT, Arimura SI, Bayer E, Bezanilla M, Botella MA, Brandizzi F, Burch-Smith TM, Chapman KD, Dünser K, Gu Y, Jaillais Y, Kirchhoff H, Otegui MS, Rosado A, Tang Y, Kleine-Vehn J, Wang P, Zolman BK. A glossary of plant cell structures: Current insights and future questions. THE PLANT CELL 2022; 34:10-52. [PMID: 34633455 PMCID: PMC8846186 DOI: 10.1093/plcell/koab247] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 09/29/2021] [Indexed: 05/03/2023]
Abstract
In this glossary of plant cell structures, we asked experts to summarize a present-day view of plant organelles and structures, including a discussion of outstanding questions. In the following short reviews, the authors discuss the complexities of the plant cell endomembrane system, exciting connections between organelles, novel insights into peroxisome structure and function, dynamics of mitochondria, and the mysteries that need to be unlocked from the plant cell wall. These discussions are focused through a lens of new microscopy techniques. Advanced imaging has uncovered unexpected shapes, dynamics, and intricate membrane formations. With a continued focus in the next decade, these imaging modalities coupled with functional studies are sure to begin to unravel mysteries of the plant cell.
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Affiliation(s)
- Byung-Ho Kang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Charles T Anderson
- Department of Biology and Center for Lignocellulose Structure and Formation, The Pennsylvania State University, University Park, Pennsylvania 16802 USA
| | - Shin-ichi Arimura
- Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Emmanuelle Bayer
- Université de Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, Villenave d'Ornon F-33140, France
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA
| | - Miguel A Botella
- Departamento de Biología Molecular y Bioquímica, Instituto de Hortifruticultura Subtropical y Mediterránea “La Mayora,” Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Universidad de Málaga, Málaga 29071, Spain
| | - Federica Brandizzi
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, Michigan 48824 USA
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824, USA
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, Michigan 48824, USA
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Kent D Chapman
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, Texas 76203, USA
| | - Kai Dünser
- Faculty of Biology, Chair of Molecular Plant Physiology (MoPP) University of Freiburg, Freiburg 79104, Germany
- Center for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, Freiburg 79104, Germany
| | - Yangnan Gu
- Department of Plant and Microbial Biology, Innovative Genomics Institute, University of California, Berkeley, California 94720, USA
| | - Yvon Jaillais
- Laboratoire Reproduction et Développement des Plantes (RDP), Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, Lyon, France
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164, USA
| | - Marisa S Otegui
- Department of Botany and Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Wisconsin 53706, USA
| | - Abel Rosado
- Department of Botany, University of British Columbia, Vancouver V6T1Z4, Canada
| | - Yu Tang
- Department of Plant and Microbial Biology, Innovative Genomics Institute, University of California, Berkeley, California 94720, USA
| | - Jürgen Kleine-Vehn
- Faculty of Biology, Chair of Molecular Plant Physiology (MoPP) University of Freiburg, Freiburg 79104, Germany
- Center for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, Freiburg 79104, Germany
| | - Pengwei Wang
- Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China
| | - Bethany Karlin Zolman
- Department of Biology, University of Missouri, St. Louis, St. Louis, Missouri 63121, USA
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8
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EIN3 and RSL4 interfere with an MYB-bHLH-WD40 complex to mediate ethylene-induced ectopic root hair formation in Arabidopsis. Proc Natl Acad Sci U S A 2021; 118:2110004118. [PMID: 34916289 DOI: 10.1073/pnas.2110004118] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/15/2021] [Indexed: 12/30/2022] Open
Abstract
The alternating cell specifications of root epidermis to form hair cells or nonhair cells in Arabidopsis are determined by the expression level of GL2, which is activated by an MYB-bHLH-WD40 (WER-GL3-TTG1) transcriptional complex. The phytohormone ethylene (ET) has a unique effect of inducing N-position epidermal cells to form root hairs. However, the molecular mechanisms underlying ET-induced ectopic root hair development remain enigmatic. Here, we show that ET promotes ectopic root hair formation through down-regulation of GL2 expression. ET-activated transcription factors EIN3 and its homolog EIL1 mediate this regulation. Molecular and biochemical analyses further revealed that EIN3 physically interacts with TTG1 and interferes with the interaction between TTG1 and GL3, resulting in reduced activation of GL2 by the WER-GL3-TTG1 complex. Furthermore, we found through genetic analysis that the master regulator of root hair elongation, RSL4, which is directly activated by EIN3, also participates in ET-induced ectopic root hair development. RSL4 negatively regulates the expression of GL2, likely through a mechanism similar to that of EIN3. Therefore, our work reveals that EIN3 may inhibit gene expression by affecting the formation of transcription-activating protein complexes and suggests an unexpected mutual inhibition between the hair elongation factor, RSL4, and the hair specification factor, GL2. Overall, this study provides a molecular framework for the integration of ET signaling and intrinsic root hair development pathway in modulating root epidermal cell specification.
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9
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Mapar M, Chopra D, Stephan L, Schrader A, Sun H, Schneeberger K, Albani M, Coupland G, Hülskamp M. Genetic and Molecular Analysis of Root Hair Development in Arabis alpina. FRONTIERS IN PLANT SCIENCE 2021; 12:767772. [PMID: 34721494 PMCID: PMC8554057 DOI: 10.3389/fpls.2021.767772] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 09/23/2021] [Indexed: 06/13/2023]
Abstract
Root hair formation in Arabidopsis thaliana is a well-established model system for epidermal patterning and morphogenesis in plants. Over the last decades, many underlying regulatory genes and well-established networks have been identified by thorough genetic and molecular analysis. In this study, we used a forward genetic approach to identify genes involved in root hair development in Arabis alpina, a related crucifer species that diverged from A. thaliana approximately 26-40 million years ago. We found all root hair mutant classes known in A. thaliana and identified orthologous regulatory genes by whole-genome or candidate gene sequencing. Our findings indicate that the gene-phenotype relationships regulating root hair development are largely conserved between A. thaliana and A. alpina. Concordantly, a detailed analysis of one mutant with multiple hairs originating from one cell suggested that a mutation in the SUPERCENTIPEDE1 (SCN1) gene is causal for the phenotype and that AaSCN1 is fully functional in A. thaliana. Interestingly, we also found differences in the regulation of root hair differentiation and morphogenesis between the species, and a subset of root hair mutants could not be explained by mutations in orthologs of known genes from A. thaliana. This analysis provides insight into the conservation and divergence of root hair regulation in the Brassicaceae.
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Affiliation(s)
- Mona Mapar
- Botanical Institute, Biocenter, Cologne University, Cologne, Germany
| | - Divykriti Chopra
- Botanical Institute, Biocenter, Cologne University, Cologne, Germany
| | - Lisa Stephan
- Botanical Institute, Biocenter, Cologne University, Cologne, Germany
| | - Andrea Schrader
- Botanical Institute, Biocenter, Cologne University, Cologne, Germany
| | - Hequan Sun
- Faculty of Biology, LMU Munich, Munich, Germany
| | | | - Maria Albani
- Botanical Institute, Biocenter, Cologne University, Cologne, Germany
- Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - George Coupland
- Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Martin Hülskamp
- Botanical Institute, Biocenter, Cologne University, Cologne, Germany
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10
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Desvoyes B, Echevarría C, Gutierrez C. A perspective on cell proliferation kinetics in the root apical meristem. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:6708-6715. [PMID: 34159378 PMCID: PMC8513163 DOI: 10.1093/jxb/erab303] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
Organogenesis in plants is primarily postembryonic and relies on a strict balance between cell division and cell expansion. The root is a particularly well-suited model to study cell proliferation in detail since the two processes are spatially and temporally separated for all the different tissues. In addition, the root is amenable to detailed microscopic analysis to identify cells progressing through the cell cycle. While it is clear that cell proliferation activity is restricted to the root apical meristem (RAM), understanding cell proliferation kinetics and identifying its parameters have required much effort over many years. Here, we review the main concepts, experimental settings, and findings aimed at obtaining a detailed knowledge of how cells proliferate within the RAM. The combination of novel tools, experimental strategies, and mathematical models has contributed to our current view of cell proliferation in the RAM. We also discuss several lines of research that need to be explored in the future.
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Affiliation(s)
- Bénédicte Desvoyes
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Nicolas Cabrera 1, Cantoblanco, 28049 Madrid, Spain
| | - Clara Echevarría
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Nicolas Cabrera 1, Cantoblanco, 28049 Madrid, Spain
| | - Crisanto Gutierrez
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Nicolas Cabrera 1, Cantoblanco, 28049 Madrid, Spain
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11
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Liu L, Jiang LG, Luo JH, Xia AA, Chen LQ, He Y. Genome-wide association study reveals the genetic architecture of root hair length in maize. BMC Genomics 2021; 22:664. [PMID: 34521344 PMCID: PMC8442424 DOI: 10.1186/s12864-021-07961-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 08/28/2021] [Indexed: 12/05/2022] Open
Abstract
Background Root hair, a special type of tubular-shaped cell, outgrows from root epidermal cell and plays important roles in the acquisition of nutrients and water, as well as interactions with biotic and abiotic stress. Although many genes involved in root hair development have been identified, genetic basis of natural variation in root hair growth has never been explored. Results Here, we utilized a maize association panel including 281 inbred lines with tropical, subtropical, and temperate origins to decipher the phenotypic diversity and genetic basis of root hair length. We demonstrated significant associations of root hair length with many metabolic pathways and other agronomic traits. Combining root hair phenotypes with 1.25 million single nucleotide polymorphisms (SNPs) via genome-wide association study (GWAS) revealed several candidate genes implicated in cellular signaling, polar growth, disease resistance and various metabolic pathways. Conclusions These results illustrate the genetic basis of root hair length in maize, offering a list of candidate genes predictably contributing to root hair growth, which are invaluable resource for the future functional investigation. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07961-z.
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Affiliation(s)
- Lin Liu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Lu-Guang Jiang
- MOE Key Laboratory of Crop Heterosis and Utilization, National Maize Improvement Center of China, China Agricultural University, Beijing, 100193, China
| | - Jin-Hong Luo
- MOE Key Laboratory of Crop Heterosis and Utilization, National Maize Improvement Center of China, China Agricultural University, Beijing, 100193, China
| | - Ai-Ai Xia
- MOE Key Laboratory of Crop Heterosis and Utilization, National Maize Improvement Center of China, China Agricultural University, Beijing, 100193, China
| | - Li-Qun Chen
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
| | - Yan He
- MOE Key Laboratory of Crop Heterosis and Utilization, National Maize Improvement Center of China, China Agricultural University, Beijing, 100193, China.
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12
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Gala HP, Lanctot A, Jean-Baptiste K, Guiziou S, Chu JC, Zemke JE, George W, Queitsch C, Cuperus JT, Nemhauser JL. A single-cell view of the transcriptome during lateral root initiation in Arabidopsis thaliana. THE PLANT CELL 2021; 33:2197-2220. [PMID: 33822225 PMCID: PMC8364244 DOI: 10.1093/plcell/koab101] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 03/31/2021] [Indexed: 05/20/2023]
Abstract
Root architecture is a major determinant of plant fitness and is under constant modification in response to favorable and unfavorable environmental stimuli. Beyond impacts on the primary root, the environment can alter the position, spacing, density, and length of secondary or lateral roots. Lateral root development is among the best-studied examples of plant organogenesis, yet there are still many unanswered questions about its earliest steps. Among the challenges faced in capturing these first molecular events is the fact that this process occurs in a small number of cells with unpredictable timing. Single-cell sequencing methods afford the opportunity to isolate the specific transcriptional changes occurring in cells undergoing this fate transition. Using this approach, we successfully captured the transcriptomes of initiating lateral root primordia in Arabidopsis thaliana and discovered many upregulated genes associated with this process. We developed a method to selectively repress target gene transcription in the xylem pole pericycle cells where lateral roots originate and demonstrated that the expression of several of these targets is required for normal root development. We also discovered subpopulations of cells in the pericycle and endodermal cell files that respond to lateral root initiation, highlighting the coordination across cell files required for this fate transition.
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Affiliation(s)
- Hardik P. Gala
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Amy Lanctot
- Department of Biology, University of Washington, Seattle, WA 98195, USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA
| | - Ken Jean-Baptiste
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Sarah Guiziou
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Jonah C. Chu
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Joseph E. Zemke
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Wesley George
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Christine Queitsch
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Josh T. Cuperus
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
- Author for correspondence: (J.T.C.); (J.L.N.)
| | - Jennifer L. Nemhauser
- Department of Biology, University of Washington, Seattle, WA 98195, USA
- Author for correspondence: (J.T.C.); (J.L.N.)
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13
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Cui Y, Zhao Q, Hu S, Jiang L. Vacuole Biogenesis in Plants: How Many Vacuoles, How Many Models? TRENDS IN PLANT SCIENCE 2020; 25:538-548. [PMID: 32407694 DOI: 10.1016/j.tplants.2020.01.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 01/19/2020] [Accepted: 01/27/2020] [Indexed: 05/22/2023]
Abstract
Vacuoles are the largest membrane-bounded organelles and have essential roles in plant growth and development, but several important questions on the biogenesis and dynamics of lytic vacuoles (LVs) remain. Here, we summarize and discuss recent research and models of vacuole formation, and propose, with testable hypotheses, that besides inherited vacuoles, plant cells can also synthesize LVs de novo from multiple organelles and routes in response to growth and development or external factors. Therefore, LVs may be further classified into different subgroups and/or populations with different pH, cargos, and functions, among which multivesicular body (MVB)-derived small vacuoles are the main source for central vacuole formation in arabidopsis root cortical cells.
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Affiliation(s)
- Yong Cui
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
| | - Qiong Zhao
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Shuai Hu
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China; CUHK Shenzhen Research Institute, Shenzhen 518057, China.
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14
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MpFEW RHIZOIDS1 miRNA-Mediated Lateral Inhibition Controls Rhizoid Cell Patterning in Marchantia polymorpha. Curr Biol 2020; 30:1905-1915.e4. [PMID: 32243863 DOI: 10.1016/j.cub.2020.03.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/18/2020] [Accepted: 03/12/2020] [Indexed: 01/27/2023]
Abstract
Lateral inhibition patterns differentiated cell types among equivalent cells during development in bacteria, metazoans, and plants. Tip-growing rhizoid cells develop among flat epidermal cells in the epidermis of the early-diverging land plant Marchantia polymorpha. We show that the majority of rhizoid cells develop individually, but some develop in linear, one-dimensional groups (chains) of between 2 and 7 rhizoid cells in wild-type plants. The distribution of rhizoid cells can be accounted for within a simple cellular automata model of lateral inhibition. The model predicted that in the absence of lateral inhibition, two-dimensional rhizoid cell groups (clusters) form. These can be larger than those formed with lateral inhibition. M. polymorpha rhizoid differentiation is positively regulated by the ROOT HAIR DEFECTIVE SIX-LIKE1 (MpRSL1) basic-helix-loop-helix (bHLH) transcription factor, which is directly repressed by the FEW RHIZOIDS1 (MpFRH1) microRNA (miRNA). To test if MpFRH1 miRNA acts during lateral inhibition, we generated loss-of-function (lof) mutants without the MpFRH1 miRNA. Two-dimensional clusters of rhizoids develop in Mpfrh1lof mutants as predicted by the model for plants that lack lateral inhibition. Furthermore, two-dimensional clusters of up to 9 rhizoid cells developed in the Mpfrh1lof mutants compared to a maximum number of 7 observed in wild-type groups. The higher steady-state levels of MpRSL1 mRNA in Mpfrh1lof mutants indicate that MpFRH1-mediated lateral inhibition involves the repression of MpRSL1 activity. Together, the modeling and genetic data indicate that MpFRH1 miRNA mediates lateral inhibition by repressing MpRSL1 during pattern formation in the M. polymorpha epidermis.
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15
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De-Jesús-García R, Rosas U, Dubrovsky JG. The barrier function of plant roots: biological bases for selective uptake and avoidance of soil compounds. FUNCTIONAL PLANT BIOLOGY : FPB 2020; 47:383-397. [PMID: 32213271 DOI: 10.1071/fp19144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 12/16/2019] [Indexed: 06/10/2023]
Abstract
The root is the main organ through which water and mineral nutrients enter the plant organism. In addition, root fulfils several other functions. Here, we propose that the root also performs the barrier function, which is essential not only for plant survival but for plant acclimation and adaptation to a constantly changing and heterogeneous soil environment. This function is related to selective uptake and avoidance of some soil compounds at the whole plant level. We review the toolkit of morpho-anatomical, structural, and other components that support this view. The components of the root structure involved in selectivity, permeability or barrier at a cellular, tissue, and organ level and their properties are discussed. In consideration of the arguments supporting barrier function of plant roots, evolutionary aspects of this function are also reviewed. Additionally, natural variation in selective root permeability is discussed which suggests that the barrier function is constantly evolving and is subject of natural selection.
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Affiliation(s)
- Ramces De-Jesús-García
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenuenida Universidad 2001, Colonia Chamilpa, Cuernavaca, Morelos 62210, Mexico
| | - Ulises Rosas
- Jardín Botánico, Instituto de Biología, Universidad Nacional Autónoma de México, 04510, CDMX, Mexico
| | - Joseph G Dubrovsky
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenuenida Universidad 2001, Colonia Chamilpa, Cuernavaca, Morelos 62210, Mexico; and Corresponding author.
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16
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Karpov PA, Sheremet YA, Blume YB, Yemets AI. Studying the Role of Protein Kinases CK1 in Organization of Cortical Microtubules in Arabidopsis thaliana Root Cells. CYTOL GENET+ 2020. [DOI: 10.3103/s0095452719060033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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17
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Kaiser S, Eisa A, Kleine-Vehn J, Scheuring D. NET4 Modulates the Compactness of Vacuoles in Arabidopsis thaliana. Int J Mol Sci 2019; 20:ijms20194752. [PMID: 31557830 PMCID: PMC6801981 DOI: 10.3390/ijms20194752] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 09/20/2019] [Accepted: 09/23/2019] [Indexed: 11/29/2022] Open
Abstract
The dimension of the plants largest organelle—the vacuole—plays a major role in defining cellular elongation rates. The morphology of the vacuole is controlled by the actin cytoskeleton, but molecular players remain largely unknown. Recently, the Networked (NET) family of membrane-associated, actin-binding proteins has been identified. Here, we show that NET4A localizes to highly constricted regions of the vacuolar membrane and contributes to vacuolar morphology. Using genetic interference, we found that deregulation of NET4 abundance increases vacuolar occupancy, and that overexpression of NET4 abundance decreases vacuolar occupancy. Our data reveal that NET4A induces more compact vacuoles, correlating with reduced cellular and organ growth in Arabidopsis thaliana.
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Affiliation(s)
- Sabrina Kaiser
- Plant Pathology, University of Kaiserslautern, 67663 Kaiserslautern, Germany.
| | - Ahmed Eisa
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Applied Life Sciences (BOKU), 1190 Vienna, Austria.
- Current address: Plant Biochemistry and Physiology, Ludwig-Maximilians-University Munich, 80539 Munich, Germany.
| | - Jürgen Kleine-Vehn
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Applied Life Sciences (BOKU), 1190 Vienna, Austria.
| | - David Scheuring
- Plant Pathology, University of Kaiserslautern, 67663 Kaiserslautern, Germany.
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Applied Life Sciences (BOKU), 1190 Vienna, Austria.
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18
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Dünser K, Gupta S, Herger A, Feraru MI, Ringli C, Kleine-Vehn J. Extracellular matrix sensing by FERONIA and Leucine-Rich Repeat Extensins controls vacuolar expansion during cellular elongation in Arabidopsis thaliana. EMBO J 2019; 38:e100353. [PMID: 30850388 PMCID: PMC6443208 DOI: 10.15252/embj.2018100353] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 01/10/2019] [Accepted: 01/21/2019] [Indexed: 01/23/2023] Open
Abstract
Cellular elongation requires the defined coordination of intra- and extracellular processes, but the underlying mechanisms are largely unknown. The vacuole is the biggest plant organelle, and its dimensions play a role in defining plant cell expansion rates. Here, we show that the increase in vacuolar occupancy enables cellular elongation with relatively little enlargement of the cytosol in Arabidopsis thaliana We demonstrate that cell wall properties are sensed and impact on the intracellular expansion of the vacuole. Using vacuolar morphology as a quantitative read-out for intracellular growth processes, we reveal that the underlying cell wall sensing mechanism requires interaction of extracellular leucine-rich repeat extensins (LRXs) with the receptor-like kinase FERONIA (FER). Our data suggest that LRXs link plasma membrane-localised FER with the cell wall, allowing this module to jointly sense and convey extracellular signals to the cell. This mechanism coordinates the onset of cell wall acidification and loosening with the increase in vacuolar size.
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Affiliation(s)
- Kai Dünser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Shibu Gupta
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Aline Herger
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Mugurel I Feraru
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Christoph Ringli
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Jürgen Kleine-Vehn
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
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19
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Timilsina R, Kim JH, Nam HG, Woo HR. Temporal changes in cell division rate and genotoxic stress tolerance in quiescent center cells of Arabidopsis primary root apical meristem. Sci Rep 2019; 9:3599. [PMID: 30837647 DOI: 10.1007/978-94-010-0936-2_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 02/15/2019] [Indexed: 05/26/2023] Open
Abstract
Plant roots provide structural support and absorb nutrients and water; therefore, their proper development and function are critical for plant survival. Extensive studies on the early stage of ontogenesis of the primary root have revealed that the root apical meristem (RAM) undergoes dynamic structural and organizational changes during early germination. Quiescent center (QC) cells, a group of slowly dividing cells at the center of the stem-cell niche, are vital for proper function and maintenance of the RAM. However, temporal aspects of molecular and cellular changes in QC cells and their regulatory mechanisms have not been well studied. In the present study, we investigated temporal changes in QC cell size, expression of QC cell-specific markers (WOX5 and QC25), and genotoxic tolerance and division rate of QC cells in the Arabidopsis primary root. Our data revealed the decreased size of QC cells and the decreased expression of the QC cell-specific markers with root age. We also found that QC cell division frequency increased with root age. Furthermore, our study provides evidence supporting the link between the transition of QC cells from a mitotically quiescent state to the frequently dividing state and the decrease in tolerance to genotoxic stress.
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Affiliation(s)
- Rupak Timilsina
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Republic of Korea
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
| | - Jin Hee Kim
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Republic of Korea
| | - Hong Gil Nam
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Republic of Korea.
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea.
| | - Hye Ryun Woo
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea.
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20
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CLASP promotes stable tethering of endoplasmic microtubules to the cell cortex to maintain cytoplasmic stability in Arabidopsis meristematic cells. PLoS One 2018; 13:e0198521. [PMID: 29894477 PMCID: PMC5997327 DOI: 10.1371/journal.pone.0198521] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/21/2018] [Indexed: 12/15/2022] Open
Abstract
Following cytokinesis in plants, Endoplasmic MTs (EMTs) assemble on the nuclear surface, forming a radial network that extends out to the cell cortex, where they attach and incorporate into the cortical microtubule (CMT) array. We found that in these post-cytokinetic cells, the MT-associated protein CLASP is enriched at sites of EMT-cortex attachment, and is required for stable EMT tethering and growth into the cell cortex. Loss of EMT-cortex anchoring in clasp-1 mutants results in destabilized EMT arrays, and is accompanied by enhanced mobility of the cytoplasm, premature vacuolation, and precocious entry into cell elongation phase. Thus, EMTs appear to maintain cells in a meristematic state by providing a structural scaffold that stabilizes the cytoplasm to counteract actomyosin-based cytoplasmic streaming forces, thereby preventing premature establishment of a central vacuole and rapid cell elongation.
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21
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Abstract
Plant postembryonic development takes place in region called meristems that represent a reserve of undifferentiated cells. In the root meristem of Arabidopsis thaliana, all tissues originate from a stem-cell niche. Stem-cell daughters undergo a finite number of cell divisions until they reach the transition zone where divisions cease and cells start to differentiate. For meristem maintenance, and therefore continuous root growth, the rate of cell differentiation must equal the rate of generation of new cells. How this balance is achieved is a central question in plant biology. In this chapter we described protocols to help the operator in approaching developmental studies on the Arabidopsis root meristem.
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Affiliation(s)
| | - Sabrina Sabatini
- Department of Biology and Biotechnology "C. Darwin", Sapienza University of Rome, Rome, Italy.
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22
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Lavrekha VV, Pasternak T, Ivanov VB, Palme K, Mironova VV. 3D analysis of mitosis distribution highlights the longitudinal zonation and diarch symmetry in proliferation activity of the Arabidopsis thaliana root meristem. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 92:834-845. [PMID: 28921702 DOI: 10.1111/tpj.13720] [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: 07/14/2017] [Revised: 08/26/2017] [Accepted: 09/04/2017] [Indexed: 05/13/2023]
Abstract
To date CYCB1;1 marker and cortex cell lengths have been conventionally used to determine the proliferation activity of the Arabidopsis root meristem. By creating a 3D map of mitosis distribution we showed that these markers overlooked that stele and endodermis save their potency to divide longer than the cortex and epidermis. Cessation of cell divisions is not a random process, so that mitotic activity within the endodermis and stele shows a diarch pattern. Mitotic activity of all root tissues peaked at the same distance from the quiescent center (QC); however, different tissues stopped dividing at different distances, with cells of the protophloem exiting the cell cycle first and the procambial cells being the last. The robust profile of mitotic activity in the root tip defines the longitudinal zonation in the meristem with the proliferation domain, where all cells are able to divide; and the transition domain, where the cell files cease to divide. 3D analysis of cytokinin deficient and cytokinin signaling mutants showed that their proliferation domain is similar to that of the wild type, but the transition domain is much longer. Our data suggest a strong inhibitory effect of cytokinin on anticlinal cell divisions in the stele.
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Affiliation(s)
- Viktoriya V Lavrekha
- Institute of Cytology and Genetics SB RAS, 10 Lavrentyev Ave., Novosibirsk, 630090, Russia
- LCTEB, Novosibirsk State University, 2 Pirogova Str., Novosibirsk, 630090, Russia
| | - Taras Pasternak
- Institute of Biology II/Molecular Plant Physiology, Centre for BioSystems Analysis, BIOSS Centre for Biological Signalling Studies University of Freiburg, Freiburg, 79104, Germany
| | - Victor B Ivanov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Str. 35, 127276, Moscow, Russia
| | - Klaus Palme
- Institute of Biology II/Molecular Plant Physiology, Centre for BioSystems Analysis, BIOSS Centre for Biological Signalling Studies University of Freiburg, Freiburg, 79104, Germany
| | - Victoria V Mironova
- Institute of Cytology and Genetics SB RAS, 10 Lavrentyev Ave., Novosibirsk, 630090, Russia
- LCTEB, Novosibirsk State University, 2 Pirogova Str., Novosibirsk, 630090, Russia
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23
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Pasternak T, Haser T, Falk T, Ronneberger O, Palme K, Otten L. A 3D digital atlas of the Nicotiana tabacum root tip and its use to investigate changes in the root apical meristem induced by the Agrobacterium 6b oncogene. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 92:31-42. [PMID: 28670824 DOI: 10.1111/tpj.13631] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Revised: 06/21/2017] [Accepted: 06/26/2017] [Indexed: 05/12/2023]
Abstract
Using the intrinsic Root Coordinate System (iRoCS) Toolbox, a digital atlas at cellular resolution has been constructed for Nicotiana tabacum roots. Mitotic cells and cells labeled for DNA replication with 5-ethynyl-2'-deoxyuridine (EdU) were mapped. The results demonstrate that iRoCS analysis can be applied to roots that are thicker than those of Arabidopsis thaliana without histological sectioning. A three-dimensional (3-D) analysis of the root tip showed that tobacco roots undergo several irregular periclinal and tangential divisions. Irrespective of cell type, rapid cell elongation starts at the same distance from the quiescent center, however, boundaries between cell proliferation and transition domains are cell-type specific. The data support the existence of a transition domain in tobacco roots. Cell endoreduplication starts in the transition domain and continues into the elongation zone. The tobacco root map was subsequently used to analyse root organization changes caused by the inducible expression of the Agrobacterium 6b oncogene. In tobacco roots that express the 6b gene, the root apical meristem was shorter and radial cell growth was reduced, but the mitotic and DNA replication indexes were not affected. The epidermis of 6b-expressing roots produced less files and underwent abnormal periclinal divisions. The periclinal division leading to mature endodermis and cortex3 cell files was delayed. These findings define additional targets for future studies on the mode of action of the Agrobacterium 6b oncogene.
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Affiliation(s)
- Taras Pasternak
- Institute of Biology II, University of Freiburg, 79104, Freiburg, Germany
| | - Thomas Haser
- Institute of Biology II, University of Freiburg, 79104, Freiburg, Germany
| | - Thorsten Falk
- Institute of Computer Science, University of Freiburg, 79110, Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany
| | - Olaf Ronneberger
- Institute of Computer Science, University of Freiburg, 79110, Freiburg, Germany
| | - Klaus Palme
- Institute of Biology II, University of Freiburg, 79104, Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany
- Centre for Biological Systems Analysis (ZBSA), University of Freiburg, 79104, Freiburg, Germany
| | - Léon Otten
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes, Rue du Général Zimmer 12, 67084, Strasbourg, France
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24
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Abstract
Iron (Fe) and phosphorus (P), the latter taken up by plants as phosphate (Pi), are two essential nutrients that determine species distribution and often limit crop yield as a result of their low availability in most soils. Pi-deficient plants improve the interception of Pi by increasing the density of root hairs, thereby expanding the volume of soil to be explored. The increase in root-hair frequency results mainly from attenuated primary root growth, a process that was shown to be dependent on the availability of external Fe. Recent data support a hypothesis in which cell elongation during Pi starvation is tuned by depositing Fe in the apoplast of cortical cells in the root elongation zone. Uptake of Fe under Pi starvation appears to proceed via an alternative, as yet unidentified, route that bypasses the default Fe transporter. Fe deposits acquired through this noncanonical Fe-uptake pathway compromises cell-to-cell communication that is critical for proper morphogenesis of epidermal cells and leads to shorter cells and higher root-hair density. An auxiliary Fe-uptake system might not only be crucial for recalibrating cell elongation in Pi-deficient plants but may also have general importance for growth on Pi- or Fe-poor soils by balancing the Pi and Fe supply.
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Affiliation(s)
- Huei-Hsuan Tsai
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica and National Chung Hsing University, Taipei, 11529, Taiwan
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Wolfgang Schmidt
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica and National Chung Hsing University, Taipei, 11529, Taiwan
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
- Biotechnology Center, National Chung-Hsing University, Taichung, 40227, Taiwan
- Genome and Systems Biology Degree Program, College of Life Science, National Taiwan University, Taipei, 10617, Taiwan
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25
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Zhang S, Huang L, Yan A, Liu Y, Liu B, Yu C, Zhang A, Schiefelbein J, Gan Y. Multiple phytohormones promote root hair elongation by regulating a similar set of genes in the root epidermis in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:6363-6372. [PMID: 27799284 PMCID: PMC5181580 DOI: 10.1093/jxb/erw400] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Multiple phytohormones, including auxin, ethylene, and cytokinin, play vital roles in regulating cell development in the root epidermis. However, their interactions in specific root hair cell developmental stages are largely unexplored. To bridge this gap, we employed genetic and pharmacological approaches as well as transcriptional analysis in order to dissect their distinct and overlapping roles in root hair initiation and elongation in Arabidopsis thaliana Our results show that among auxin, ethylene, and cytokinin, only ethylene induces ectopic root hair cells in wild-type plants, implying a special role of ethylene in the hair initiation stage. In the subsequent elongation stage, however, auxin, ethylene, and cytokinin enhance root hair tip growth equally. Our data also suggest that the effect of cytokinin is independent from auxin and ethylene in this process. Exogenous cytokinin restores root hair elongation when the auxin and ethylene signal is defective, whereas auxin and ethylene also sustain elongation in the absence of the cytokinin signal. Notably, transcriptional analyses demonstrated that auxin, ethylene, and cytokinin regulate a similar set of root hair-specific genes. Together these analyses provide important clues regarding the mechanism of hormonal interactions and regulation in the formation of single-cell structures.
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Affiliation(s)
- Shan Zhang
- Zhejiang Key Laboratory of Crop Germplasm, Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Linli Huang
- Zhejiang Key Laboratory of Crop Germplasm, Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - An Yan
- Zhejiang Key Laboratory of Crop Germplasm, Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Yihua Liu
- Zhejiang Key Laboratory of Crop Germplasm, Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Bohan Liu
- Zhejiang Key Laboratory of Crop Germplasm, Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Chunyan Yu
- Zhejiang Key Laboratory of Crop Germplasm, Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Aidong Zhang
- Zhejiang Key Laboratory of Crop Germplasm, Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - John Schiefelbein
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Yinbo Gan
- Zhejiang Key Laboratory of Crop Germplasm, Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
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Le Deunff E, Lecourt J, Malagoli P. Fine-tuning of root elongation by ethylene: a tool to study dynamic structure-function relationships between root architecture and nitrate absorption. ANNALS OF BOTANY 2016; 118:607-620. [PMID: 27411681 PMCID: PMC5055632 DOI: 10.1093/aob/mcw123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 02/26/2016] [Accepted: 05/12/2016] [Indexed: 05/08/2023]
Abstract
Background Recently developed genetic and pharmacological approaches have been used to explore NO3-/ethylene signalling interactions and how the modifications in root architecture by pharmacological modulation of ethylene biosynthesis affect nitrate uptake. Key Results Structure-function studies combined with recent approaches to chemical genomics highlight the non-specificity of commonly used inhibitors of ethylene biosynthesis such as AVG (l-aminoethoxyvinylglycine). Indeed, AVG inhibits aminotransferases such as ACC synthase (ACS) and tryptophan aminotransferase (TAA) involved in ethylene and auxin biosynthesis but also some aminotransferases implied in nitrogen (N) metabolism. In this framework, it can be assumed that the products of nitrate assimilation and hormones may interact through a hub in carbon (C) and N metabolism to drive the root morphogenetic programme (RMP). Although ethylene/auxin interactions play a major role in cell division and elongation in root meristems, shaping of the root system depends also on energetic considerations. Based on this finding, the analysis is extended to nutrient ion-hormone interactions assuming a fractal or constructal model for root development. Conclusion Therefore, the tight control of root structure-function in the RMP may explain why over-expressing nitrate transporter genes to decouple structure-function relationships and improve nitrogen use efficiency (NUE) has been unsuccessful.
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Affiliation(s)
- Erwan Le Deunff
- Université de Caen Basse-Normandie, UMR Écophysiologie Végétale & Agronomie, Nutritions NCS, F-14032 Caen, France
- INRA, UMR 950, Écophysiologie Végétale & Agronomie, Nutritions NCS, F-14032 Caen, France
| | - Julien Lecourt
- East Malling Research, New Road, East Malling ME19 6BJ, Kent, UK
| | - Philippe Malagoli
- Université Blaise Pascal-INRA, 24, avenue des Landais, BP 80 006, F-63177 Aubière, France
- INRA, UMR 547 PIAF, Bâtiment Biologie Végétale Recherche, BP 80 006, F-63177 Aubière, France
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27
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Affiliation(s)
- Silvia Costa
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
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28
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Salazar-Henao JE, Vélez-Bermúdez IC, Schmidt W. The regulation and plasticity of root hair patterning and morphogenesis. Development 2016; 143:1848-58. [DOI: 10.1242/dev.132845] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Root hairs are highly specialized cells found in the epidermis of plant roots that play a key role in providing the plant with water and mineral nutrients. Root hairs have been used as a model system for understanding both cell fate determination and the morphogenetic plasticity of cell differentiation. Indeed, many studies have shown that the fate of root epidermal cells, which differentiate into either root hair or non-hair cells, is determined by a complex interplay of intrinsic and extrinsic cues that results in a predictable but highly plastic pattern of epidermal cells that can vary in shape, size and function. Here, we review these studies and discuss recent evidence suggesting that environmental information can be integrated at multiple points in the root hair morphogenetic pathway and affects multifaceted processes at the chromatin, transcriptional and post-transcriptional levels.
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Affiliation(s)
| | | | - Wolfgang Schmidt
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
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29
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Discriminative gene co-expression network analysis uncovers novel modules involved in the formation of phosphate deficiency-induced root hairs in Arabidopsis. Sci Rep 2016; 6:26820. [PMID: 27220366 PMCID: PMC4879556 DOI: 10.1038/srep26820] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 05/10/2016] [Indexed: 12/22/2022] Open
Abstract
Cell fate and differentiation in the Arabidopsis root epidermis are genetically defined but remain plastic to environmental signals such as limited availability of inorganic phosphate (Pi). Root hairs of Pi-deficient plants are more frequent and longer than those of plants grown under Pi-replete conditions. To dissect genes involved in Pi deficiency-induced root hair morphogenesis, we constructed a co-expression network of Pi-responsive genes against a customized database that was assembled from experiments in which differentially expressed genes that encode proteins with validated functions in root hair development were over-represented. To further filter out less relevant genes, we combined this procedure with a search for common cis-regulatory elements in the promoters of the selected genes. In addition to well-described players and processes such as auxin signalling and modifications of primary cell walls, we discovered several novel aspects in the biology of root hairs induced by Pi deficiency, including cell cycle control, putative plastid-to-nucleus signalling, pathogen defence, reprogramming of cell wall-related carbohydrate metabolism, and chromatin remodelling. This approach allows the discovery of novel of aspects of a biological process from transcriptional profiles with high sensitivity and accuracy.
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30
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Nishihama R, Ishida S, Urawa H, Kamei Y, Kohchi T. Conditional Gene Expression/Deletion Systems for Marchantia polymorpha Using its Own Heat-Shock Promoter and Cre/loxP-Mediated Site-Specific Recombination. PLANT & CELL PHYSIOLOGY 2016; 57:271-280. [PMID: 26148498 DOI: 10.1093/pcp/pcv102] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 06/29/2015] [Indexed: 06/04/2023]
Abstract
The liverwort Marchantia polymorpha is an emerging model plant suitable for addressing, using genetic approaches, various evolutionary questions in the land plant lineage. Haploid dominancy in its life cycle facilitates genetic analyses, but conversely limits the ability to isolate mutants of essential genes. To overcome this issue and to be employed in cell lineage, mosaic and cell autonomy analyses, we developed a system that allows conditional gene expression and deletion using a promoter of a heat-shock protein (HSP) gene and the Cre/loxP site-specific recombination system. Because the widely used promoter of the Arabidopsis HSP18.2 gene did not operate in M. polymorpha, we identified a promoter of an endogenous HSP gene, MpHSP17.8A1, which exhibited a highly inducible transient expression level upon heat shock with a low basal activity level. Reporter genes fused to this promoter were induced globally in thalli under whole-plant heat treatment and also locally using a laser-assisted targeted heating technique. By expressing Cre fused to the glucocorticoid receptor under the control of the MpHSP17.8A1 promoter, a low background, sufficiently inducible control for loxP-mediated recombination could be achieved in M. polymorpha. Based on these findings, we developed a Gateway technology-based binary vector for the conditional induction of gene deletions.
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Affiliation(s)
- Ryuichi Nishihama
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502 Japan
| | - Sakiko Ishida
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502 Japan
| | - Hiroko Urawa
- Faculty of Education, Gifu Shotoku Gakuen University, Gifu, 501-6194 Japan
| | - Yasuhiro Kamei
- Spectrography and Bioimaging Facility, NIBB Core Facilities, National Institute for Basic Biology, Okazaki, Aichi, 444-8585 Japan Department of Basic Biology in the School of Life Science, SOKENDAI (the Graduate University for Advanced Studies), Okazaki, Aichi, 444-8585 Japan
| | - Takayuki Kohchi
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502 Japan
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31
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Slovak R, Ogura T, Satbhai SB, Ristova D, Busch W. Genetic control of root growth: from genes to networks. ANNALS OF BOTANY 2016; 117:9-24. [PMID: 26558398 PMCID: PMC4701154 DOI: 10.1093/aob/mcv160] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/28/2015] [Indexed: 05/08/2023]
Abstract
BACKGROUND Roots are essential organs for higher plants. They provide the plant with nutrients and water, anchor the plant in the soil, and can serve as energy storage organs. One remarkable feature of roots is that they are able to adjust their growth to changing environments. This adjustment is possible through mechanisms that modulate a diverse set of root traits such as growth rate, diameter, growth direction and lateral root formation. The basis of these traits and their modulation are at the cellular level, where a multitude of genes and gene networks precisely regulate development in time and space and tune it to environmental conditions. SCOPE This review first describes the root system and then presents fundamental work that has shed light on the basic regulatory principles of root growth and development. It then considers emerging complexities and how they have been addressed using systems-biology approaches, and then describes and argues for a systems-genetics approach. For reasons of simplicity and conciseness, this review is mostly limited to work from the model plant Arabidopsis thaliana, in which much of the research in root growth regulation at the molecular level has been conducted. CONCLUSIONS While forward genetic approaches have identified key regulators and genetic pathways, systems-biology approaches have been successful in shedding light on complex biological processes, for instance molecular mechanisms involving the quantitative interaction of several molecular components, or the interaction of large numbers of genes. However, there are significant limitations in many of these methods for capturing dynamic processes, as well as relating these processes to genotypic and phenotypic variation. The emerging field of systems genetics promises to overcome some of these limitations by linking genotypes to complex phenotypic and molecular data using approaches from different fields, such as genetics, genomics, systems biology and phenomics.
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Affiliation(s)
- Radka Slovak
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Takehiko Ogura
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Santosh B Satbhai
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Daniela Ristova
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Wolfgang Busch
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
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32
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Balcerowicz D, Schoenaers S, Vissenberg K. Cell Fate Determination and the Switch from Diffuse Growth to Planar Polarity in Arabidopsis Root Epidermal Cells. FRONTIERS IN PLANT SCIENCE 2015; 6:1163. [PMID: 26779192 PMCID: PMC4688357 DOI: 10.3389/fpls.2015.01163] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 12/07/2015] [Indexed: 05/19/2023]
Abstract
Plant roots fulfill important functions as they serve in water and nutrient uptake, provide anchorage of the plant body in the soil and in some species form the site of symbiotic interactions with soil-living biota. Root hairs, tubular-shaped outgrowths of specific epidermal cells, significantly increase the root's surface area and aid in these processes. In this review we focus on the molecular mechanisms that determine the hair and non-hair cell fate of epidermal cells and that define the site on the epidermal cell where the root hair will be initiated (=planar polarity determination). In the model plant Arabidopsis, trichoblast and atrichoblast cell fate results from intra- and intercellular position-dependent signaling and from complex feedback loops that ultimately regulate GL2 expressing and non-expressing cells. When epidermal cells reach the end of the root expansion zone, root hair promoting transcription factors dictate the establishment of polarity within epidermal cells followed by the selection of the root hair initiation site at the more basal part of the trichoblast. Molecular players in the abovementioned processes as well as the role of phytohormones are discussed, and open areas for future experiments are identified.
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Affiliation(s)
| | | | - Kris Vissenberg
- Integrated Molecular Plant Physiology Research, Department Biology, University of AntwerpAntwerpen, Belgium
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33
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Li DX, Chen WQ, Xu ZH, Bai SN. HISTONE DEACETYLASE6-Defective Mutants Show Increased Expression and Acetylation of ENHANCER OF TRIPTYCHON AND CAPRICE1 and GLABRA2 with Small But Significant Effects on Root Epidermis Cellular Pattern. PLANT PHYSIOLOGY 2015; 168:1448-58. [PMID: 26143251 PMCID: PMC4528770 DOI: 10.1104/pp.15.00821] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 06/26/2015] [Indexed: 05/03/2023]
Abstract
Cellular patterning in the Arabidopsis (Arabidopsis thaliana) root epidermis is dependent on positional information, the transmission of which involves histone acetylation. Here, we report that HISTONE DEACETYLASE6 (HDA6) has significant effects on this cellular patterning. Mutation of HDA6 led to ectopic hair cells in the nonhair positions of root epidermis in Arabidopsis, based on an analysis of paraffin sections stained with Toluidine Blue. While HDA6 was present throughout the root tip, epidermis-specific complementation with HDA6 could rescue the hda6 phenotype. Both transcript levels and expression patterns of ENHANCER OF TRIPTYCHON AND CAPRICE1 (ETC1) and GLABRA2 (GL2) in the root tip were affected in hda6. Consistent with these changes in expression, HDA6 directly bound to the promoter regions of ETC1 and GL2, and acetylation of histone H3 on these promoter regions and acetylation of histone H4 on the ETC1 promoter region was increased in the hda6 mutant. Taken together, these results indicate that HDA6 affects the cellular patterning of Arabidopsis root epidermis through altering the histone acetylation status of ETC1 and GL2 promoters and thereby affects the expression of these two components of the core transcription factor network determining epidermal cell fates. Our findings thus provide new insights into the role of histone acetylation in root epidermis cell patterning.
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Affiliation(s)
- Dong-Xu Li
- State Key Laboratory of Protein and Plant Gene Research, College of Life Science, Peking University, Beijing 100871, China; andNational Center of Plant Gene Research, Beijing 100871, China
| | - Wen-Qian Chen
- State Key Laboratory of Protein and Plant Gene Research, College of Life Science, Peking University, Beijing 100871, China; andNational Center of Plant Gene Research, Beijing 100871, China
| | - Zhi-Hong Xu
- State Key Laboratory of Protein and Plant Gene Research, College of Life Science, Peking University, Beijing 100871, China; andNational Center of Plant Gene Research, Beijing 100871, China
| | - Shu-Nong Bai
- State Key Laboratory of Protein and Plant Gene Research, College of Life Science, Peking University, Beijing 100871, China; andNational Center of Plant Gene Research, Beijing 100871, China
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34
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Müller J, Toev T, Heisters M, Teller J, Moore K, Hause G, Dinesh D, Bürstenbinder K, Abel S. Iron-Dependent Callose Deposition Adjusts Root Meristem Maintenance to Phosphate Availability. Dev Cell 2015; 33:216-30. [DOI: 10.1016/j.devcel.2015.02.007] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 12/12/2014] [Accepted: 02/09/2015] [Indexed: 12/11/2022]
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35
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Löfke C, Dünser K, Scheuring D, Kleine-Vehn J. Auxin regulates SNARE-dependent vacuolar morphology restricting cell size. eLife 2015; 4. [PMID: 25742605 PMCID: PMC4384535 DOI: 10.7554/elife.05868] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 03/05/2015] [Indexed: 11/13/2022] Open
Abstract
The control of cellular growth is central to multicellular patterning. In plants, the encapsulating cell wall literally binds neighbouring cells to each other and limits cellular sliding/migration. In contrast to its developmental importance, growth regulation is poorly understood in plants. Here, we reveal that the phytohormone auxin impacts on the shape of the biggest plant organelle, the vacuole. TIR1/AFBs-dependent auxin signalling posttranslationally controls the protein abundance of vacuolar SNARE components. Genetic and pharmacological interference with the auxin effect on vacuolar SNAREs interrelates with auxin-resistant vacuolar morphogenesis and cell size regulation. Vacuolar SNARE VTI11 is strictly required for auxin-reliant vacuolar morphogenesis and loss of function renders cells largely insensitive to auxin-dependent growth inhibition. Our data suggests that the adaptation of SNARE-dependent vacuolar morphogenesis allows auxin to limit cellular expansion, contributing to root organ growth rates. DOI:http://dx.doi.org/10.7554/eLife.05868.001 In plants and animals, the way that cells grow is carefully controlled to enable tissues and organs to form and be maintained. This is especially important in plants because the cells are attached to each other by their cell walls. This means that, unlike some animal cells, plant cells are not able to move around as a plant's organs develop. Plant cells contain a large storage compartment called the vacuole, which occupies 30–80% of a cell's volume. The volume of the vacuole increases as the cell increases in size, and some researchers have suggested that the vacuole might help to control cell growth. A plant hormone called auxin can alter the growth of plant cells. However, this hormone's effect depends on the position of the cell in the plant; for example, it inhibits the growth of root cells, but promotes the growth of cells in the shoots and leaves. Nevertheless, it is not clear precisely how auxin controls plant cell growth. Here, Löfke et al. studied the effect of auxin on the appearance of vacuoles in a type of plant cell—called the root epidermal cell—on the surface of the roots of a plant called Arabidopsis thaliana. The experiments show that auxin alters the appearance of the vacuoles in these cells so they become smaller in size. At the same time, auxin also inhibits the growth of these cells. Löfke et al. found that auxin increases the amount of certain proteins in the membrane that surrounds the vacuole. These proteins belong to the SNARE family and one SNARE protein in particular, called VTI11, is required for auxin to be able to both alter the appearance of the vacuoles and restrict the growth of root epidermal cells. Enzymes called PI4 kinases were also shown to be involved in the control of the SNARE proteins in response to the auxin hormone. Löfke et al.'s findings suggest that auxin restricts the growth of root epidermal cells by controlling the amount of SNARE proteins in the vacuole membrane. The next challenge will be to understand precisely how the shape of the vacuole is controlled and how it contributes to cell growth. DOI:http://dx.doi.org/10.7554/eLife.05868.002
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Affiliation(s)
- Christian Löfke
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Kai Dünser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - David Scheuring
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Jürgen Kleine-Vehn
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
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36
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Pietra S, Lang P, Grebe M. SABRE is required for stabilization of root hair patterning in Arabidopsis thaliana. PHYSIOLOGIA PLANTARUM 2015; 153:440-453. [PMID: 25124848 DOI: 10.1111/ppl.12257] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 06/18/2014] [Accepted: 06/20/2014] [Indexed: 06/03/2023]
Abstract
Patterned differentiation of distinct cell types is essential for the development of multicellular organisms. The root epidermis of Arabidopsis thaliana is composed of alternating files of root hair and non-hair cells and represents a model system for studying the control of cell-fate acquisition. Epidermal cell fate is regulated by a network of genes that translate positional information from the underlying cortical cell layer into a specific pattern of differentiated cells. While much is known about the genes of this network, new players continue to be discovered. Here we show that the SABRE (SAB) gene, known to mediate microtubule organization, anisotropic cell growth and planar polarity, has an effect on root epidermal hair cell patterning. Loss of SAB function results in ectopic root hair formation and destabilizes the expression of cell fate and differentiation markers in the root epidermis, including expression of the WEREWOLF (WER) and GLABRA2 (GL2) genes. Double mutant analysis reveal that wer and caprice (cpc) mutants, defective in core components of the epidermal patterning pathway, genetically interact with sab. This suggests that SAB may act on epidermal patterning upstream of WER and CPC. Hence, we provide evidence for a role of SAB in root epidermal patterning by affecting cell-fate stabilization. Our work opens the door for future studies addressing SAB-dependent functions of the cytoskeleton during root epidermal patterning.
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Affiliation(s)
- Stefano Pietra
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, SE-90187, Sweden
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37
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Robinson DO, Roeder AHK. Themes and variations in cell type patterning in the plant epidermis. Curr Opin Genet Dev 2015; 32:55-65. [PMID: 25727387 DOI: 10.1016/j.gde.2015.01.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/26/2015] [Accepted: 01/27/2015] [Indexed: 01/16/2023]
Abstract
It has recently become evident that plant development, like animal development, has molecular patterning modules that are reused again and again to create different cell type patterns. Here we focus on three of these plant modules: (1) the MYB-bHLH-WD40 protein complex, (2) the transmembrane calpain protease DEFECTIVE KERNEL1 (DEK1), and (3) homeodomain leucine zipper (HD-ZIP) class IV transcription factors acting in concert with SIAMESE-related cyclin-dependent kinase inhibitors. These three modules initiate the patterning of multiple cell types in the plant epidermis: the regular spacing of trichomes (leaf hairs), the stripes of root hairs, diverse pigmentation patterns in petals, the scattering of giant cells, and the files of bulliform cells. Varied combinations of players and additional regulatory inputs partially account for the diversity of patterns that are generated by reusing the same molecular mechanisms.
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Affiliation(s)
- Dana Olivia Robinson
- Weill Institute for Cell and Molecular Biology and School of Integrative Plant Science, Section of Plant Biology, Cornell University, Ithaca, NY 14853, USA
| | - Adrienne H K Roeder
- Weill Institute for Cell and Molecular Biology and School of Integrative Plant Science, Section of Plant Biology, Cornell University, Ithaca, NY 14853, USA.
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38
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Volatile signalling by sesquiterpenes from ectomycorrhizal fungi reprogrammes root architecture. Nat Commun 2015; 6:6279. [PMID: 25703994 PMCID: PMC4346619 DOI: 10.1038/ncomms7279] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 01/13/2015] [Indexed: 11/08/2022] Open
Abstract
The mutualistic association of roots with ectomycorrhizal fungi promotes plant health and is a hallmark of boreal and temperate forests worldwide. In the pre-colonization phase, before direct contact, lateral root (LR) production is massively stimulated, yet little is known about the signals exchanged during this step. Here, we identify sesquiterpenes (SQTs) as biologically active agents emitted by Laccaria bicolor while interacting with Populus or Arabidopsis. We show that inhibition of fungal SQT production by lovastatin strongly reduces LR proliferation and that (-)-thujopsene, a low-abundance SQT, is sufficient to stimulate LR formation in the absence of the fungus. Further, we show that the ectomycorrhizal ascomycote, Cenococcum geophilum, which cannot synthesize SQTs, does not promote LRs. We propose that the LR-promoting SQT signal creates a win-win situation by enhancing the root surface area for plant nutrient uptake and by improving fungal access to plant-derived carbon via root exudates.
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39
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Grierson C, Nielsen E, Ketelaarc T, Schiefelbein J. Root hairs. THE ARABIDOPSIS BOOK 2014; 12:e0172. [PMID: 24982600 PMCID: PMC4075452 DOI: 10.1199/tab.0172] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Roots hairs are cylindrical extensions of root epidermal cells that are important for acquisition of nutrients, microbe interactions, and plant anchorage. The molecular mechanisms involved in the specification, differentiation, and physiology of root hairs in Arabidopsis are reviewed here. Root hair specification in Arabidopsis is determined by position-dependent signaling and molecular feedback loops causing differential accumulation of a WD-bHLH-Myb transcriptional complex. The initiation of root hairs is dependent on the RHD6 bHLH gene family and auxin to define the site of outgrowth. Root hair elongation relies on polarized cell expansion at the growing tip, which involves multiple integrated processes including cell secretion, endomembrane trafficking, cytoskeletal organization, and cell wall modifications. The study of root hair biology in Arabidopsis has provided a model cell type for insights into many aspects of plant development and cell biology.
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Affiliation(s)
- Claire Grierson
- School of Biological Sciences, University of Bristol, Bristol, UK BS8 1UG
| | - Erik Nielsen
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA 48109
| | - Tijs Ketelaarc
- Laboratory of Cell Biology, Wageningen University, 6708 PB Wageningen, The Netherlands
| | - John Schiefelbein
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA 48109
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40
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Fridman Y, Elkouby L, Holland N, Vragović K, Elbaum R, Savaldi-Goldstein S. Root growth is modulated by differential hormonal sensitivity in neighboring cells. Genes Dev 2014; 28:912-20. [PMID: 24736847 PMCID: PMC4003282 DOI: 10.1101/gad.239335.114] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Coherent plant growth requires spatial integration of hormonal pathways and cell wall remodeling activities. However, the mechanisms governing sensitivity to hormones and how cell wall structure integrates with hormonal effects are poorly understood. We found that coordination between two types of epidermal root cells, hair and nonhair cells, establishes root sensitivity to the plant hormones brassinosteroids (BRs). While expression of the BR receptor BRASSINOSTEROID-INSENSITIVE1 (BRI1) in hair cells promotes cell elongation in all tissues, its high relative expression in nonhair cells is inhibitory. Elevated ethylene and deposition of crystalline cellulose underlie the inhibitory effect of BRI1. We propose that the relative spatial distribution of BRI1, and not its absolute level, fine-tunes growth.
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Affiliation(s)
- Yulia Fridman
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel
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41
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Cheng Y, Zhu W, Chen Y, Ito S, Asami T, Wang X. Brassinosteroids control root epidermal cell fate via direct regulation of a MYB-bHLH-WD40 complex by GSK3-like kinases. eLife 2014; 3:eLife.02525. [PMID: 24771765 PMCID: PMC4005458 DOI: 10.7554/elife.02525] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 04/01/2014] [Indexed: 02/06/2023] Open
Abstract
In Arabidopsis, root hair and non-hair cell fates are determined by a MYB-bHLH-WD40 transcription factor complex and are regulated by many internal and environmental cues. Brassinosteroids play important roles in regulating root hair specification by unknown mechanisms. Here, we systematically examined root hair phenotypes in brassinosteroid-related mutants, and found that brassinosteroid signaling inhibits root hair formation through GSK3-like kinases or upstream components. We found that with enhanced brassinosteroid signaling, GL2, a cell fate marker for non-hair cells, is ectopically expressed in hair cells, while its expression in non-hair cells is suppressed when BR signaling is reduced. Genetic analysis demonstrated that brassinosteroid-regulated root epidermal cell patterning is dependent on the WER-GL3/EGL3-TTG1 transcription factor complex. One of the GSK3-like kinases, BIN2, interacted with and phosphorylated EGL3, and EGL3s mutated at phosphorylation siteswere retained in hair cell nuclei. BIN2 phosphorylated TTG1 to inhibit the activity of the WER-GL3/EGL3-TTG1 complex. Thus, our study provides insights into the mechanism of brassinosteroid regulation of root hair patterning.
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Affiliation(s)
- Yinwei Cheng
- State Key Laboratory of Genetic Engineering, and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China
| | - Wenjiao Zhu
- State Key Laboratory of Genetic Engineering, and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China
| | - Yuxiao Chen
- State Key Laboratory of Genetic Engineering, and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China
| | - Shinsaku Ito
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Tadao Asami
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Xuelu Wang
- State Key Laboratory of Genetic Engineering, and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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Chopra D, Wolff H, Span J, Schellmann S, Coupland G, Albani MC, Schrader A, Hülskamp M. Analysis of TTG1 function in Arabis alpina. BMC PLANT BIOLOGY 2014; 14:16. [PMID: 24406039 PMCID: PMC3904473 DOI: 10.1186/1471-2229-14-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 01/07/2014] [Indexed: 05/20/2023]
Abstract
BACKGROUND In Arabidopsis thaliana (A. thaliana) the WD40 protein TRANSPARENT TESTA GLABRA1 (TTG1) controls five traits relevant for the adaptation of plants to environmental changes including the production of proanthocyanidin, anthocyanidin, seed coat mucilage, trichomes and root hairs. The analysis of different Brassicaceae species suggests that the function of TTG1 is conserved within the family. RESULTS In this work, we studied the function of TTG1 in Arabis alpina (A. alpina). A comparison of wild type and two Aattg1 alleles revealed that AaTTG1 is involved in the regulation of all five traits. A detailed analysis of the five traits showed striking phenotypic differences between A. alpina and A. thaliana such that trichome formation occurs also at later stages of leaf development and that root hairs form at non-root hair positions. CONCLUSIONS The evolutionary conservation of the regulation of the five traits by TTG1 on the one hand and the striking phenotypic differences make A. alpina a very interesting genetic model system to study the evolution of TTG1-dependent gene regulatory networks at a functional level.
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Affiliation(s)
- Divykriti Chopra
- Botanical Institute, Biocenter, Cologne University, Zülpicher Straße 47b, 50674 Cologne, Germany
| | - Heike Wolff
- Botanical Institute, Biocenter, Cologne University, Zülpicher Straße 47b, 50674 Cologne, Germany
| | - Johannes Span
- Botanical Institute, Biocenter, Cologne University, Zülpicher Straße 47b, 50674 Cologne, Germany
| | - Swen Schellmann
- Botanical Institute, Biocenter, Cologne University, Zülpicher Straße 47b, 50674 Cologne, Germany
| | - George Coupland
- Max Planck Institute for Plant Breeding, Carl-von-Linne-Weg 10, 50829 Cologne, Germany
| | - Maria C Albani
- Botanical Institute, Biocenter, Cologne University, Zülpicher Straße 47b, 50674 Cologne, Germany
- Max Planck Institute for Plant Breeding, Carl-von-Linne-Weg 10, 50829 Cologne, Germany
| | - Andrea Schrader
- Botanical Institute, Biocenter, Cologne University, Zülpicher Straße 47b, 50674 Cologne, Germany
| | - Martin Hülskamp
- Botanical Institute, Biocenter, Cologne University, Zülpicher Straße 47b, 50674 Cologne, Germany
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Racolta A, Bryan AC, Tax FE. The receptor-like kinases GSO1 and GSO2 together regulate root growth in Arabidopsis through control of cell division and cell fate specification. Dev Dyn 2013; 243:257-78. [PMID: 24123341 DOI: 10.1002/dvdy.24066] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Revised: 09/19/2013] [Accepted: 09/19/2013] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND The root apical meristem of Arabidopsis is established post-embryonically as the main source of root cells, and its activity is maintained by complex bidirectional signaling between stem cells and mature cells. The receptor-like kinases GASSHO1 (GSO1) and GSO2 have been shown to regulate aerial epidermal function and seedling growth in Arabidopsis. RESULTS Here we show that gso1; gso2 seedlings also have root growth and patterning defects. Analyses of mutant root morphology indicate abnormal numbers of cells in longitudinal files and radial cell layers, as well as aberrant stem cell division planes. gso1; gso2 double mutants misexpress markers for stem cells and differentiated root cell types. In addition, gso1; gso2 root growth defects, but not marker missexpression or patterning phenotypes, are rescued by growth on media containing metabolizable sugars. CONCLUSIONS We conclude that GSO1 and GSO2 function together in intercellular signaling to positively regulate cell proliferation, differentiation of root cell types, and stem cell identity. In addition, GSO1 and GSO2 control seedling root growth by modulating sucrose response after germination.
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Affiliation(s)
- Adriana Racolta
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona
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Savage N, Yang TJW, Chen CY, Lin KL, Monk NAM, Schmidt W. Positional signaling and expression of ENHANCER OF TRY AND CPC1 are tuned to increase root hair density in response to phosphate deficiency in Arabidopsis thaliana. PLoS One 2013; 8:e75452. [PMID: 24130712 PMCID: PMC3794009 DOI: 10.1371/journal.pone.0075452] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 08/15/2013] [Indexed: 11/19/2022] Open
Abstract
Phosphate (Pi) deficiency induces a multitude of responses aimed at improving the acquisition of Pi, including an increased density of root hairs. To understand the mechanisms involved in Pi deficiency-induced alterations of the root hair phenotype in Arabidopsis (Arabidopsis thaliana), we analyzed the patterning and length of root epidermal cells under control and Pi-deficient conditions in wild-type plants and in four mutants defective in the expression of master regulators of cell fate, CAPRICE (CPC), ENHANCER OF TRY AND CPC 1 (ETC1), WEREWOLF (WER) and SCRAMBLED (SCM). From this analysis we deduced that the longitudinal cell length of root epidermal cells is dependent on the correct perception of a positional signal ('cortical bias') in both control and Pi-deficient plants; mutants defective in the receptor of the signal, SCM, produced short cells characteristic of root hair-forming cells (trichoblasts). Simulating the effect of cortical bias on the time-evolving probability of cell fate supports a scenario in which a compromised positional signal delays the time point at which non-hair cells opt out the default trichoblast pathway, resulting in short, trichoblast-like non-hair cells. Collectively, our data show that Pi-deficient plants increase root hair density by the formation of shorter cells, resulting in a higher frequency of hairs per unit root length, and additional trichoblast cell fate assignment via increased expression of ETC1.
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Affiliation(s)
- Natasha Savage
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Thomas J. W. Yang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Chung Ying Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Kai-Lan Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Nicholas A. M. Monk
- Division of Applied Mathematics, School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Loughborough, United Kingdom
| | - Wolfgang Schmidt
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
- Genome and Systems Biology Degree Program, College of Life Science, National Taiwan University, Taipei, Taiwan
- * E-mail:
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Löfke C, Dünser K, Kleine-Vehn J. Epidermal patterning genes impose non-cell autonomous cell size determination and have additional roles in root meristem size control. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:864-875. [PMID: 23945284 DOI: 10.1111/jipb.12097] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 07/29/2013] [Indexed: 06/02/2023]
Abstract
The regulation of cellular growth is of vital importance for embryonic and postembryonic patterning. Growth regulation in the epidermis has importance for organ growth rates in roots and shoots, proposing epidermal cells as an interesting model for cellular growth regulation. Here we assessed whether the root epidermis is a suitable model system to address cell size determination. In Arabidopsis thaliana L., root epidermal cells are regularly spaced in neighbouring tricho- (root hair) and atrichoblast (non-hair) cells, showing already distinct cell size regulation in the root meristem. We determined cell sizes in the root meristem and at the onset of cellular elongation, revealing that not only division rates but also cellular shape is distinct in tricho- and atrichoblasts. Intriguingly, epidermal-patterning mutants, failing to define differential vacuolization in neighbouring epidermal cell files, also display non-differential growth. Using these epidermal-patterning mutants, we show that polarized growth behaviour of epidermal tricho- and atrichoblast is interdependent, suggesting non-cell autonomous signals to integrate tissue expansion. Besides the interweaved cell-type-dependent growth mechanism, we reveal an additional role for epidermal patterning genes in root meristem size and organ growth regulation. We conclude that epidermal cells represent a suitable model system to study cell size determination and interdependent tissue growth.
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Affiliation(s)
- Christian Löfke
- Department of Applied Genetics and Cell Biology, Vienna Institute of Biotechnology (VIBT), University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, 1190, Vienna, Austria
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Offringa R, Kleine-Vehn J. Cell polarity and development. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:786-8. [PMID: 23953999 DOI: 10.1111/jipb.12099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Affiliation(s)
- Remko Offringa
- Molecular and Developmental Genetics, Institute Biology Leiden, Leiden University, Sylvius Laboratory, Sylviusweg 72, 2333, BE, The Netherlands.
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Lin Q, Aoyama T. Pathways for epidermal cell differentiation via the homeobox gene GLABRA2: update on the roles of the classic regulator. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2012; 54:729-37. [PMID: 22943441 DOI: 10.1111/j.1744-7909.2012.01159.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Recent plant development studies have identified regulatory pathways for epidermal cell differentiation in Arabidopsis thaliana. Interestingly, some of such pathways contain transcriptional networks with a common structure in which the homeobox gene GLABLA2 (GL2) is downstream of the transactivation complex consisting of MYB, bHLH, and WD40 proteins. Here, we review the role of GL2 as an output device of the conserved network, and update the knowledge of epidermal cell differentiation pathways downstream of GL2. Despite the consistent position of GL2 within the network, its role in epidermal tissues varies; in the root epidermis, GL2 promotes non-hair cell differentiation after cell pattern formation, whereas in the leaf epidermis, it is likely to be involved in both pattern formation and differentiation of trichomes. GL2 expression levels act as quantitative factors for initiation of cell differentiation in the root and leaf epidermis; the quantity of hairless cells in non-root hair cell files is reduced by gl2 mutations in a semi-dominant manner, and entopically additive expression of GL2 and a heterozygous gl2 mutation increase and decrease the number of trichomes, respectively. Although few direct target genes have been identified, evidence from genetic and expression analyses suggests that GL2 directly regulates genes with various hierarchies in epidermal cell differentiation pathways.
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Affiliation(s)
- Qing Lin
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
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Tominaga-Wada R, Ishida T, Wada T. New insights into the mechanism of development of Arabidopsis root hairs and trichomes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2011; 286:67-106. [PMID: 21199780 DOI: 10.1016/b978-0-12-385859-7.00002-1] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Epidermis cell differentiation in Arabidopsis thaliana is a model system for understanding the mechanisms leading to the developmental end state of plant cells. Both root hairs and trichomes differentiate from epidermal cells and molecular genetic analyses using Arabidopsis mutants have demonstrated that the differentiation of root hairs and trichomes is regulated by similar molecular mechanisms. Molecular-genetic approaches have led to the identification of many genes that are involved in epidermal cell differentiation, most of which encode transcription factors that induce the expression of genes active in both root hair and trichome development. Control of cell growth after fate determination has also been studied using Arabidopsis mutants.
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Affiliation(s)
- Rumi Tominaga-Wada
- Interdisciplinary Research Organization, University of Miyazaki, Gakuen Kibanadai-nishi, Miyazaki, Japan
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Hassan H, Scheres B, Blilou I. JACKDAW controls epidermal patterning in the Arabidopsis root meristem through a non-cell-autonomous mechanism. Development 2010; 137:1523-9. [DOI: 10.1242/dev.048777] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In Arabidopsis, specification of the hair and non-hair epidermal cell types is position dependent, in that hair cells arise over clefts in the underlying cortical cell layer. Epidermal patterning is determined by a network of transcriptional regulators that respond to an as yet unknown cue from underlying tissues. Previously, we showed that JACKDAW (JKD), a zinc finger protein, localizes in the quiescent centre and the ground tissue, and regulates tissue boundaries and asymmetric cell division by delimiting SHORT-ROOT movement. Here, we provide evidence that JKD controls position-dependent signals that regulate epidermal-cell-type patterning. JKD is required for appropriately patterned expression of the epidermal cell fate regulators GLABRA2, CAPRICE and WEREWOLF. Genetic interaction studies indicate that JKD operates upstream of the epidermal patterning network in a SCRAMBLED (SCM)-dependent fashion after embryogenesis, but acts independent of SCM in embryogenesis. Tissue-specific induction experiments indicate non-cell-autonomous action of JKD from the underlying cortex cell layer to specify epidermal cell fate. Our findings are consistent with a model where JKD induces a signal in every cortex cell that is more abundant in the hair cell position owing to the larger surface contact of cells located over a cleft.
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Affiliation(s)
- Hala Hassan
- Molecular Genetics, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Ben Scheres
- Molecular Genetics, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Ikram Blilou
- Molecular Genetics, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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Abstract
Plant post-embryonic development takes place in the meristems. In the root of the model plant Arabidopsis thaliana, stem cells organized in a stem-cell niche in the apex of the root meristem generate transit-amplifying cells, which undergo additional division in the proximal meristem and differentiate in the elongation/differentiation zone. For meristem maintenance, and therefore continuous root growth, the rate of cell differentiation must equal the rate of generation of new cells: how this balance is achieved is a central question in plant development. We have shown that maintenance of the Arabidopsis root meristem size is established by a balance between the antagonistic effects of cytokinin, which promotes cell differentiation, and auxin, which promotes cell division. Cytokinin antagonizes auxin in a specific developmental domain (the vascular tissue transition zone) from where it controls the differentiation rate of all the other root tissues. Here, we describe protocols to analyze development of root meristems.
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