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Skalák J, Vercruyssen L, Claeys H, Hradilová J, Černý M, Novák O, Plačková L, Saiz-Fernández I, Skaláková P, Coppens F, Dhondt S, Koukalová Š, Zouhar J, Inzé D, Brzobohatý B. Multifaceted activity of cytokinin in leaf development shapes its size and structure in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 97:805-824. [PMID: 30748050 DOI: 10.1111/tpj.14285] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 01/05/2019] [Accepted: 01/10/2019] [Indexed: 05/20/2023]
Abstract
The phytohormone cytokinin has been shown to affect many aspects of plant development ranging from the regulation of the shoot apical meristem to leaf senescence. However, some studies have reported contradictory effects of cytokinin on leaf physiology. Therefore cytokinin treatments cause both chlorosis and increased greening and both lead to decrease or increase in cell size. To elucidate this multifaceted role of cytokinin in leaf development, we have employed a system of temporal controls over the cytokinin pool and investigated the consequences of modulated cytokinin levels in the third leaf of Arabidopsis. We show that, at the cell proliferation phase, cytokinin is needed to maintain cell proliferation by blocking the transition to cell expansion and the onset of photosynthesis. Transcriptome profiling revealed regulation by cytokinin of a gene suite previously shown to affect cell proliferation and expansion and thereby a molecular mechanism by which cytokinin modulates a molecular network underlying the cellular responses. During the cell expansion phase, cytokinin stimulates cell expansion and differentiation. Consequently, a cytokinin excess at the cell expansion phase results in an increased leaf and rosette size fueled by higher cell expansion rate, yielding higher shoot biomass. Proteome profiling revealed the stimulation of primary metabolism by cytokinin, in line with an increased sugar content that is expected to increase turgor pressure, representing the driving force of cell expansion. Therefore, the developmental timing of cytokinin content fluctuations, together with a tight control of primary metabolism, is a key factor mediating transitions from cell proliferation to cell expansion in leaves.
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Affiliation(s)
- Jan Skalák
- Department of Molecular Biology and Radiobiology, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, CZ-61300, Brno, Czech Republic
| | - Liesbeth Vercruyssen
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
- VIB Center for Plant Systems Biology, 9052, Ghent, Belgium
| | - Hannes Claeys
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
- VIB Center for Plant Systems Biology, 9052, Ghent, Belgium
| | - Jana Hradilová
- Department of Molecular Biology and Radiobiology, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, CZ-61300, Brno, Czech Republic
| | - Martin Černý
- Department of Molecular Biology and Radiobiology, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, CZ-61300, Brno, Czech Republic
| | - Ondřej Novák
- Laboratory of Growth Regulators, The Czech Academy of Sciences, Institute of Experimental Botany & Palacký University, Šlechtitelů 27, CZ-78371, Olomouc, Czech Republic
| | - Lenka Plačková
- Laboratory of Growth Regulators, The Czech Academy of Sciences, Institute of Experimental Botany & Palacký University, Šlechtitelů 27, CZ-78371, Olomouc, Czech Republic
| | - Iñigo Saiz-Fernández
- Department of Molecular Biology and Radiobiology, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, CZ-61300, Brno, Czech Republic
| | - Patricie Skaláková
- Department of Molecular Biology and Radiobiology, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, CZ-61300, Brno, Czech Republic
| | - Frederik Coppens
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
- VIB Center for Plant Systems Biology, 9052, Ghent, Belgium
| | - Stijn Dhondt
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
- VIB Center for Plant Systems Biology, 9052, Ghent, Belgium
| | - Šárka Koukalová
- Department of Molecular Biology and Radiobiology, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, CZ-61300, Brno, Czech Republic
- CEITEC - Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-61300, Brno, Czech Republic
| | - Jan Zouhar
- Department of Molecular Biology and Radiobiology, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, CZ-61300, Brno, Czech Republic
- CEITEC - Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-61300, Brno, Czech Republic
| | - Dirk Inzé
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
- VIB Center for Plant Systems Biology, 9052, Ghent, Belgium
| | - Břetislav Brzobohatý
- Department of Molecular Biology and Radiobiology, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, CZ-61300, Brno, Czech Republic
- CEITEC - Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-61300, Brno, Czech Republic
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, CZ-61265, Brno, Czech Republic
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52
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Olszak M, Truman W, Stefanowicz K, Sliwinska E, Ito M, Walerowski P, Rolfe S, Malinowski R. Transcriptional profiling identifies critical steps of cell cycle reprogramming necessary for Plasmodiophora brassicae-driven gall formation in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 97:715-729. [PMID: 30431210 PMCID: PMC6850046 DOI: 10.1111/tpj.14156] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 10/31/2018] [Accepted: 11/06/2018] [Indexed: 05/08/2023]
Abstract
Plasmodiophora brassicae is a soil-borne biotroph whose life cycle involves reprogramming host developmental processes leading to the formation of galls on its underground parts. Formation of such structures involves modification of the host cell cycle leading initially to hyperplasia, increasing the number of cells to be invaded, followed by overgrowth of cells colonised by the pathogen. Here we show that P. brassicae infection stimulates formation of the E2Fa/RBR1 complex and upregulation of MYB3R1, MYB3R4 and A- and B-type cyclin expression. These factors were previously described as important regulators of the G2-M cell cycle checkpoint. As a consequence of this manipulation, a large population of host hypocotyl cells are delayed in cell cycle exit and maintained in the proliferative state. We also report that, during further maturation of galls, enlargement of host cells invaded by the pathogen involves endoreduplication leading to increased ploidy levels. This study characterises two aspects of the cell cycle reprogramming efforts of P. brassicae: systemic, related to the disturbance of host hypocotyl developmental programs by preventing cell cycle exit; and local, related to the stimulation of cell enlargement via increased endocycle activity.
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Affiliation(s)
- Marcin Olszak
- Department of Integrative Plant BiologyInstitute of Plant Genetics of the Polish Academy of Sciencesul. Strzeszyńska 3460‐479PoznańPoland
| | - William Truman
- Department of Integrative Plant BiologyInstitute of Plant Genetics of the Polish Academy of Sciencesul. Strzeszyńska 3460‐479PoznańPoland
| | - Karolina Stefanowicz
- Department of Integrative Plant BiologyInstitute of Plant Genetics of the Polish Academy of Sciencesul. Strzeszyńska 3460‐479PoznańPoland
| | - Elwira Sliwinska
- Laboratory of Molecular Biology and CytometryDepartment of Plant Genetics, Physiology and BiotechnologyUTP University of Science and TechnologyKaliskiego Ave. 785‐789BydgoszczPoland
| | - Masaki Ito
- Graduate School of Bioagricultural SciencesNagoya UniversityChikusaNagoya464‐8601Japan
| | - Piotr Walerowski
- Department of Integrative Plant BiologyInstitute of Plant Genetics of the Polish Academy of Sciencesul. Strzeszyńska 3460‐479PoznańPoland
| | - Stephen Rolfe
- Department of Animal and Plant SciencesUniversity of SheffieldSheffieldS10 2TNUK
| | - Robert Malinowski
- Department of Integrative Plant BiologyInstitute of Plant Genetics of the Polish Academy of Sciencesul. Strzeszyńska 3460‐479PoznańPoland
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53
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Wybouw B, De Rybel B. Cytokinin - A Developing Story. TRENDS IN PLANT SCIENCE 2019; 24:177-185. [PMID: 30446307 DOI: 10.1016/j.tplants.2018.10.012] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/15/2018] [Accepted: 10/18/2018] [Indexed: 05/21/2023]
Abstract
In the past decade tremendous advances have been made in understanding the biosynthesis, perception, and signaling pathways of the plant hormone cytokinin. It also became clear that interfering with any of these steps greatly impacts all on stages of growth and development. This has recently spurted renewed effort to understand how cytokinin signaling affects developmental processes. As a result, new insights on the role of cytokinin signaling and the downstream targets during, for example, shoot apical meristem, flower, female gametophyte, stomata and vascular development are being unraveled. In this review we aim to give a comprehensive overview of recent findings on how cytokinin influences growth and development in plants, and highlight areas for future research.
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Affiliation(s)
- Brecht Wybouw
- Ghent University, Department of Plant Biotechnology and Bioinformatics, 9052 Ghent, Belgium; VIB Center for Plant Systems Biology, 9052 Ghent, Belgium
| | - Bert De Rybel
- Ghent University, Department of Plant Biotechnology and Bioinformatics, 9052 Ghent, Belgium; VIB Center for Plant Systems Biology, 9052 Ghent, Belgium.
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High levels of auxin signalling define the stem-cell organizer of the vascular cambium. Nature 2019; 565:485-489. [PMID: 30626967 DOI: 10.1038/s41586-018-0837-0] [Citation(s) in RCA: 150] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 12/04/2018] [Indexed: 11/08/2022]
Abstract
Wood, a type of xylem tissue, originates from cell proliferation of the vascular cambium. Xylem is produced inside, and phloem outside, of the cambium1. Morphogenesis in plants is typically coordinated by organizer cells that direct the adjacent stem cells to undergo programmed cell division and differentiation. The location of the vascular cambium stem cells and whether the organizer concept applies to the cambium are currently unknown2. Here, using lineage-tracing and molecular genetic studies in the roots of Arabidopsis thaliana, we show that cells with a xylem identity direct adjacent vascular cambial cells to divide and function as stem cells. Thus, these xylem-identity cells constitute an organizer. A local maximum of the phytohormone auxin, and consequent expression of CLASS III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIP III) transcription factors, promotes xylem identity and cellular quiescence of the organizer cells. Additionally, the organizer maintains phloem identity in a non-cell-autonomous fashion. Consistent with this dual function of the organizer cells, xylem and phloem originate from a single, bifacial stem cell in each radial cell file, which confirms the classical theory of a uniseriate vascular cambium3. Clones that display high levels of ectopically activated auxin signalling differentiate as xylem vessels; these clones induce cell divisions and the expression of cambial and phloem markers in the adjacent cells, which suggests that a local auxin-signalling maximum is sufficient to specify a stem-cell organizer. Although vascular cambium has a unique function among plant meristems, the stem-cell organizer of this tissue shares features with the organizers of root and shoot meristems.
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55
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Hellmann E, Ko D, Ruonala R, Helariutta Y. Plant Vascular Tissues-Connecting Tissue Comes in All Shapes. PLANTS (BASEL, SWITZERLAND) 2018; 7:E109. [PMID: 30551673 PMCID: PMC6313914 DOI: 10.3390/plants7040109] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 11/23/2018] [Accepted: 12/07/2018] [Indexed: 12/23/2022]
Abstract
For centuries, humans have grown and used structures based on vascular tissues in plants. One could imagine that life would have developed differently without wood as a resource for building material, paper, heating energy, or fuel and without edible tubers as a food source. In this review, we will summarise the status of research on Arabidopsis thaliana vascular development and subsequently focus on how this knowledge has been applied and expanded in research on the wood of trees and storage organs of crop plants. We will conclude with an outlook on interesting open questions and exciting new research opportunities in this growing and important field.
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Affiliation(s)
- Eva Hellmann
- The Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, UK.
| | - Donghwi Ko
- The Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, UK.
| | - Raili Ruonala
- The Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, UK.
- Institute of Biotechnology, Department of Biological and Environmental Sciences, University of Helsinki, FI-00014 Helsinki, Finland.
| | - Ykä Helariutta
- The Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, UK.
- Institute of Biotechnology, Department of Biological and Environmental Sciences, University of Helsinki, FI-00014 Helsinki, Finland.
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56
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Poza-Viejo L, Abreu I, González-García MP, Allauca P, Bonilla I, Bolaños L, Reguera M. Boron deficiency inhibits root growth by controlling meristem activity under cytokinin regulation. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 270:176-189. [PMID: 29576071 DOI: 10.1016/j.plantsci.2018.02.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 12/19/2017] [Accepted: 02/06/2018] [Indexed: 05/29/2023]
Abstract
Significant advances have been made in the last years trying to identify regulatory pathways that control plant responses to boron (B) deficiency. Still, there is a lack of a deep understanding of how they act regulating growth and development under B limiting conditions. Here, we analyzed the impact of B deficit on cell division leading to root apical meristem (RAM) disorganization. Our results reveal that inhibition of cell proliferation under the regulatory control of cytokinins (CKs) is an early event contributing to root growth arrest under B deficiency. An early recovery of QC46:GUS expression after transferring B-deficient seedlings to control conditions revealed a role of B in the maintenance of QC identity whose loss under deficiency occurred at later stages of the stress. Additionally, the D-type cyclin CYCD3 overexpressor and triple mutant cycd3;1-3 were used to evaluate the effect on mitosis inhibition at the G1-S boundary. Overall, this study supports the hypothesis that meristem activity is inhibited by B deficiency at early stages of the stress as it does cell elongation. Likewise, distinct regulatory mechanisms seem to take place depending on the severity of the stress. The results presented here are key to better understand early signaling responses under B deficiency.
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Affiliation(s)
- Laura Poza-Viejo
- Departament of Biology, Universidad Autónoma de Madrid, c/Darwin 2, Campus de Cantoblanco, 28049 Madrid, Spain; Present address: Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo UPM, 28223, Pozuelo de Alarcón, Madrid, Spain
| | - Isidro Abreu
- Departament of Biology, Universidad Autónoma de Madrid, c/Darwin 2, Campus de Cantoblanco, 28049 Madrid, Spain; Present address: Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo UPM, 28223, Pozuelo de Alarcón, Madrid, Spain
| | | | - Paúl Allauca
- Departament of Biology, Universidad Autónoma de Madrid, c/Darwin 2, Campus de Cantoblanco, 28049 Madrid, Spain
| | - Ildefonso Bonilla
- Departament of Biology, Universidad Autónoma de Madrid, c/Darwin 2, Campus de Cantoblanco, 28049 Madrid, Spain
| | - Luis Bolaños
- Departament of Biology, Universidad Autónoma de Madrid, c/Darwin 2, Campus de Cantoblanco, 28049 Madrid, Spain
| | - María Reguera
- Departament of Biology, Universidad Autónoma de Madrid, c/Darwin 2, Campus de Cantoblanco, 28049 Madrid, Spain.
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57
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Transcriptome dynamics at Arabidopsis graft junctions reveal an intertissue recognition mechanism that activates vascular regeneration. Proc Natl Acad Sci U S A 2018; 115:E2447-E2456. [PMID: 29440499 PMCID: PMC5878008 DOI: 10.1073/pnas.1718263115] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Plant grafting is an ancient and agriculturally important technique. Despite its widespread use, little is known about how plants graft. Here, we perform a genome-wide transcriptome analysis of tissues above and below graft junctions. We observed a sequential activation of genes important for vascular development including cambium-, phloem-, and xylem-related genes. Massive changes in gene expression that rapidly differentiate the top of the graft from the bottom occur. These changes disappear as the graft heals and the vasculature reconnects. Many genes below the junction rapidly respond to the presence of attached tissues including genes involved in vascular differentiation and cell division. This intertissue communication process occurs independently of functional vascular connections and acts as a signal to activate vascular regeneration. The ability for cut tissues to join and form a chimeric organism is a remarkable property of many plants; however, grafting is poorly characterized at the molecular level. To better understand this process, we monitored genome-wide gene expression changes in grafted Arabidopsis thaliana hypocotyls. We observed a sequential activation of genes associated with cambium, phloem, and xylem formation. Tissues above and below the graft rapidly developed an asymmetry such that many genes were more highly expressed on one side than on the other. This asymmetry correlated with sugar-responsive genes, and we observed an accumulation of starch above the graft junction. This accumulation decreased along with asymmetry once the sugar-transporting vascular tissues reconnected. Despite the initial starvation response below the graft, many genes associated with vascular formation were rapidly activated in grafted tissues but not in cut and separated tissues, indicating that a recognition mechanism was activated independently of functional vascular connections. Auxin, which is transported cell to cell, had a rapidly elevated response that was symmetric, suggesting that auxin was perceived by the root within hours of tissue attachment to activate the vascular regeneration process. A subset of genes was expressed only in grafted tissues, indicating that wound healing proceeded via different mechanisms depending on the presence or absence of adjoining tissues. Such a recognition process could have broader relevance for tissue regeneration, intertissue communication, and tissue fusion events.
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58
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Affiliation(s)
- Raili Ruonala
- Institute of Biotechnology and Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland
- The Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, United Kingdom;, ,
| | - Donghwi Ko
- The Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, United Kingdom;, ,
| | - Ykä Helariutta
- Institute of Biotechnology and Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland
- The Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, United Kingdom;, ,
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Maurya JP, Bhalerao RP. Photoperiod- and temperature-mediated control of growth cessation and dormancy in trees: a molecular perspective. ANNALS OF BOTANY 2017; 120:351-360. [PMID: 28605491 PMCID: PMC5591416 DOI: 10.1093/aob/mcx061] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Indexed: 05/03/2023]
Abstract
BACKGROUND How plants adapt their developmental patterns to regular seasonal changes is an important question in biology. The annual growth cycle in perennial long-lived trees is yet another example of how plants can adapt to seasonal changes. The two main signals that plants rely on to respond to seasonal changes are photoperiod and temperature, and these signals have critical roles in the temporal regulation of the annual growth cycle of trees. SCOPE This review presents the latest findings to provide insight into the molecular mechanisms that underlie how photoperiodic and temperature signals regulate seasonal growth in trees. CONCLUSION The results point to a high level of conservation in the signalling pathways that mediate photoperiodic control of seasonal growth in trees and flowering in annual plants such as arabidopsis. Furthermore, the data indicate that symplastic communication may mediate certain aspects of seasonal growth. Although considerable insight into the control of phenology in model plants such as poplar and spruce has been obtained, the future challenge is extending these studies to other, non-model trees.
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Affiliation(s)
- Jay P Maurya
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
| | - Rishikesh P Bhalerao
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
- For correspondence. E-mail
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60
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Ragni L, Greb T. Secondary growth as a determinant of plant shape and form. Semin Cell Dev Biol 2017; 79:58-67. [PMID: 28864343 DOI: 10.1016/j.semcdb.2017.08.050] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 07/26/2017] [Accepted: 08/28/2017] [Indexed: 02/06/2023]
Abstract
Plants are the primary producers of biomass on earth. As an almost stereotypic feature, higher plants generate continuously growing bodies mediated by the activity of different groups of stem cells, the meristems. Shoot and root thickening is one of the fundamental growth processes determining form and function of these bodies. Mediated by a group of cylindrical meristems located below organ surfaces, vascular and protective tissues are continuously generated in a highly plastic manner, a competence essential for the survival in an ever changing environment. Acknowledging the fundamental role of this process, which is overall designated as secondary growth, we discuss in this review our current knowledge about the evolution and molecular regulation of the vascular cambium. The cambium is the meristem responsible for the formation of wood and bast, the two types of vascular tissues important for long-distance transport of water and assimilates, respectively. Although regulatory patterns are only beginning to emerge, we show that cambium activity represents a highly rewarding model for studying cell fate decisions, tissue patterning and differentiation, which has experienced an outstanding phylogenetic diversification.
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Affiliation(s)
- Laura Ragni
- ZMBP, University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany.
| | - Thomas Greb
- Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.
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61
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Tang S, Li L, Wang Y, Chen Q, Zhang W, Jia G, Zhi H, Zhao B, Diao X. Genotype-specific physiological and transcriptomic responses to drought stress in Setaria italica (an emerging model for Panicoideae grasses). Sci Rep 2017; 7:10009. [PMID: 28855520 PMCID: PMC5577110 DOI: 10.1038/s41598-017-08854-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 07/14/2017] [Indexed: 01/17/2023] Open
Abstract
Understanding drought-tolerance mechanisms and identifying genetic dominance are important for crop improvement. Setaria italica, which is extremely drought-tolerant, has been regarded as a model plant for studying stress biology. Moreover, different genotypes of S. italica have evolved various drought-tolerance/avoidance mechanisms that should be elucidated. Physiological and transcriptomic comparisons between drought-tolerant S. italica cultivar 'Yugu1' and drought-sensitive 'An04' were conducted. 'An04' had higher yields and more efficient photosystem activities than 'Yugu1' under well-watered conditions, and this was accompanied by positive brassinosteroid regulatory actions. However, 'An04's growth advantage was severely repressed by drought, while 'Yugu1' maintained normal growth under a water deficiency. High-throughput sequencing suggested that the S. italica transcriptome was severely remodelled by genotype × environment interactions. Expression profiles of genes related to phytohormone metabolism and signalling, transcription factors, detoxification, and other stress-related proteins were characterised, revealing genotype-dependent and -independent drought responses in different S. italica genotypes. Combining our data with drought-tolerance-related QTLs, we identified 20 candidate genes that contributed to germination and early seedling' drought tolerance in S. italica. Our analysis provides a comprehensive picture of how different S. italica genotypes respond to drought, and may be used for the genetic improvement of drought tolerance in Poaceae crops.
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Affiliation(s)
- Sha Tang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, 100081, Beijing, People's Republic of China
| | - Lin Li
- College of Life Science, Hebei Normal University, 050012, Shijiazhuang, People's Republic of China
| | - Yongqiang Wang
- Institute of Cotton, Hebei Academy of Agricultural and Forestry Sciences, 050030, Shijiazhuang, People's Republic of China
| | - Qiannan Chen
- College of Life Science, Hebei Normal University, 050012, Shijiazhuang, People's Republic of China
| | - Wenying Zhang
- Institute of Dryland Agriculture, Hebei Academy of Agricultural and Forestry Sciences, 050000, Hengshui, People's Republic of China
| | - Guanqing Jia
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, 100081, Beijing, People's Republic of China
| | - Hui Zhi
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, 100081, Beijing, People's Republic of China
| | - Baohua Zhao
- College of Life Science, Hebei Normal University, 050012, Shijiazhuang, People's Republic of China
| | - Xianmin Diao
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, 100081, Beijing, People's Republic of China.
- College of Life Science, Hebei Normal University, 050012, Shijiazhuang, People's Republic of China.
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62
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Xiang J, Tang S, Zhi H, Jia G, Wang H, Diao X. Loose Panicle1 encoding a novel WRKY transcription factor, regulates panicle development, stem elongation, and seed size in foxtail millet [Setaria italica (L.) P. Beauv.]. PLoS One 2017; 12:e0178730. [PMID: 28570666 PMCID: PMC5453597 DOI: 10.1371/journal.pone.0178730] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 05/19/2017] [Indexed: 01/29/2023] Open
Abstract
Panicle development is an important agronomic trait that aids in determining crop productivity. Foxtail millet and its wild ancestor green foxtail have recently been used as model systems to dissect gene functions. Here, we characterized a recessive mutant of foxtail millet, loose-panicle 1 (lp1), which showed pleiotropic phenotypes, such as a lax primary branching pattern, aberrant branch morphology, semi-dwarfism, and enlarged seed size. The loose panicle phenotype was attributed to increased panicle lengths and decreased primary branch numbers. Map-based cloning, combined with high-throughput sequencing, revealed that LP1, which encodes a novel WRKY transcription factor, is responsible for the mutant phenotype. A phylogenetic analysis revealed that LP1 belongs to the Group I WRKY subfamily, which possesses two WRKY domains (WRKY I and II). A single G-to-A transition in the fifth intron of LP1 resulted in three disorganized splicing events in mutant plants. For each of these aberrant splice variants, the normal C2H2 motif in the WRKY II domain was completely disrupted, resulting in a loss-of-function mutation. LP1 mRNA was expressed in all of the tissues examined, with higher expression levels observed in inflorescences, roots, and seeds at the grain-filling stage. A subcellular localization analysis showed that LP1 predominantly accumulated in the nucleus, which confirmed its role as a transcriptional regulator. This study provides novel insights into the roles of WRKY proteins in regulating reproductive organ development in plants and may help to develop molecular markers associated with crop yields.
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Affiliation(s)
- Jishan Xiang
- Gansu Provincial Key Lab of Aridland Crop Science/Gansu Key Lab of Crop Improvement & Germplasm Enhancement/College of Agronomy, Gansu Agricultural University, Lanzhou, People’s Republic of China
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, People’s Republic of China
- Chifeng University, Chifeng, People’s Republic of China
| | - Sha Tang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, People’s Republic of China
| | - Hui Zhi
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, People’s Republic of China
| | - Guanqing Jia
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, People’s Republic of China
| | - Huajun Wang
- Gansu Provincial Key Lab of Aridland Crop Science/Gansu Key Lab of Crop Improvement & Germplasm Enhancement/College of Agronomy, Gansu Agricultural University, Lanzhou, People’s Republic of China
- * E-mail: (HJW); (XMD)
| | - Xianmin Diao
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, People’s Republic of China
- * E-mail: (HJW); (XMD)
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Lara-Núñez A, García-Ayala BB, Garza-Aguilar SM, Flores-Sánchez J, Sánchez-Camargo VA, Bravo-Alberto CE, Vázquez-Santana S, Vázquez-Ramos JM. Glucose and sucrose differentially modify cell proliferation in maize during germination. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2017; 113:20-31. [PMID: 28157579 DOI: 10.1016/j.plaphy.2017.01.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 12/19/2016] [Accepted: 01/20/2017] [Indexed: 05/21/2023]
Abstract
Glucose and sucrose play a dual role: as carbon and energy sources and as signaling molecules. In order to address the impact that sugars may have on maize seeds during germination, embryo axes were incubated with or without either of the two sugars. Expression of key cell cycle markers and protein abundance, cell patterning and de novo DNA synthesis in root meristem zones were analyzed. Embryo axes without added sugars in imbibition medium were unable to grow after 7 days; in sucrose, embryo axes developed seminal and primary roots with numerous root hairs, whereas in glucose axes showed a twisted morphology, no root hair formation but callus-like structures on adventitious and primary seminal roots. More and smaller cells were observed with glucose treatment in root apical meristems. de novo DNA synthesis was stimulated more by glucose than by sucrose. At 24 h of imbibition, expression of ZmCycD2;2a and ZmCycD4;2 was increased by sucrose and reduced by glucose. CDKA1;1 and CDKA2;1 expression was stimulated equally by both sugars. Protein abundance patterns were modified by sugars: ZmCycD2 showed peaks on glucose at 12 and 36 h of imbibition whereas sucrose promoted ZmCycD3 protein accumulation. In presence of glucose ZmCycD3, ZmCycD4 and ZmCycD6 protein abundance was reduced after 24 h. Finally, both sugars stimulated ZmCDKA protein accumulation but at different times. Overall, even though glucose appears to act as a stronger mitogen stimulator, sucrose stimulated the expression of more cell cycle markers during germination. This work provides evidence of a differential response of cell cycle markers to sucrose and glucose during maize germination that may affect the developmental program during plantlet establishment.
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Affiliation(s)
- Aurora Lara-Núñez
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
| | - Brendy B García-Ayala
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Sara M Garza-Aguilar
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Jesús Flores-Sánchez
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Victor A Sánchez-Camargo
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Carlos E Bravo-Alberto
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Sonia Vázquez-Santana
- Facultad de Ciencias, Departamento de Biología Comparada, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Jorge M Vázquez-Ramos
- Facultad de Química, Departamento de Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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64
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Singh RK, Svystun T, AlDahmash B, Jönsson AM, Bhalerao RP. Photoperiod- and temperature-mediated control of phenology in trees - a molecular perspective. THE NEW PHYTOLOGIST 2017; 213:511-524. [PMID: 27901272 DOI: 10.1111/nph.14346] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 10/07/2016] [Indexed: 05/17/2023]
Abstract
Contents 511 I. 511 II. 512 III. 513 IV. 513 V. 517 VI. 517 VII. 521 VIII. 521 Acknowledgements 521 References 521 SUMMARY: Trees growing in boreal and temperate regions synchronize their growth with seasonal climatic changes in adaptive responses that are essential for their survival. These trees cease growth before the winter and establish a dormant state during which growth cessation is maintained by repression of responses to growth-promotive signals. Reactivation of growth in the spring follows the release from dormancy promoted by prolonged exposure to low temperature during the winter. The timing of the key events and regulation of the molecular programs associated with the key stages of the annual growth cycle are controlled by two main environmental cues: photoperiod and temperature. Recently, key components mediating photoperiodic control of growth cessation and bud set have been identified, and striking similarities have been observed in signaling pathways controlling growth cessation in trees and floral transition in Arabidopsis. Although less well understood, the regulation of bud dormancy and bud burst may involve cell-cell communication and chromatin remodeling. Here, we discuss current knowledge of the molecular-level regulation of the annual growth cycle of woody trees in temperate and boreal regions, and identify key questions that need to be addressed in the future.
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Affiliation(s)
- Rajesh Kumar Singh
- Department of Forest Genetics and Plant Physiology, SLU, S-901 83, Umeå, Sweden
| | - Tetiana Svystun
- Department of Physical Geography and Ecosystem Science, Lund University, Sölvegatan 12, S-223 62, Lund, Sweden
| | - Badr AlDahmash
- College of Science, King Saud University, 11451, Riyadh, Saudi Arabia
| | - Anna Maria Jönsson
- Department of Physical Geography and Ecosystem Science, Lund University, Sölvegatan 12, S-223 62, Lund, Sweden
| | - Rishikesh P Bhalerao
- Department of Forest Genetics and Plant Physiology, SLU, S-901 83, Umeå, Sweden
- College of Science, King Saud University, 11451, Riyadh, Saudi Arabia
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65
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Bhalerao RP, Fischer U. Environmental and hormonal control of cambial stem cell dynamics. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:79-87. [PMID: 27965368 DOI: 10.1093/jxb/erw466] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Perennial trees have the amazing ability to adjust their growth rate to both adverse and favorable seasonally reoccurring environmental conditions over hundreds of years. In trunks and stems, the basis for the tuning of seasonal growth rate is the regulation of cambial stem cell activity. Cambial stem cell quiescence and dormancy protect the tree from potential physiological and genomic damage caused by adverse growing conditions and may permit a long lifespan. Cambial dormancy and longevity are both aspects of a tree's life for which the study of cambial stem cell behavior in the annual model plant Arabidopsis is inadequate. Recent functional analyses of hormone perception and catabolism mutants in Populus indicate that shoot-derived long-range signals, as well as local cues, steer cambial activity. Auxin is central to the regulation of cambial activity and probably also maintenance. Emerging genome editing and phenotyping technologies will enable the identification of down-stream targets of hormonal action and facilitate the genetic dissection of complex traits of cambial biology.
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Affiliation(s)
- Rishikesh P Bhalerao
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, SE-90183, Sweden
| | - Urs Fischer
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, SE-90183, Sweden
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66
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Abstract
Vascular tissue, comprising xylem and phloem, is responsible for the transport of water and nutrients throughout the plant body. Such tissue is continually produced from stable populations of stem cells, specifically the procambium during primary growth and the cambium during secondary growth. As the majority of plant biomass is produced by the cambium, there is an obvious demand for an understanding of the genetic mechanisms that control the rate of vascular cell division. Moreover, wood is an industrially important product of the cambium, and research is beginning to uncover similar mechanisms in trees such as poplar. This review focuses upon recent work that has identified the major molecular pathways that regulate procambial and cambial activity.
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Affiliation(s)
- Liam Campbell
- University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Simon Turner
- University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
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67
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Johnsson C, Fischer U. Cambial stem cells and their niche. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 252:239-245. [PMID: 27717460 DOI: 10.1016/j.plantsci.2016.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/28/2016] [Accepted: 08/06/2016] [Indexed: 06/06/2023]
Abstract
Unlike animals, plants often have an indefinite genetic potency to form new organs throughout their entire lifespan. Growth and organogenesis are driven by cell divisions in meristems at distinct sites within the plant. Since the meristems contributing to axial thickening in dicots (cambia) are separated from places where axes elongate (apical meristems); there is a need of communication to coordinate growth. In their behavior, some meristematic cells resemble animal stem cells whose daughter cells either maintain the capacity to divide over a long period of time or undergo differentiation. The behavior of stem cells is regulated by their microenvironment, the so called niche. The stem- and niche-cell concept is now also widely accepted for apical meristems. An integral part of the cambial niche has recently been localized to the phloem. It steers cell division activity in the cambium via the release of a peptide signal and may be a hub to integrate signals from other stem cell populations to coordinate growth. Although these signals have yet to be determined, the discovery of the cambial niche cells will pave the way for a better understanding of inter-meristematic communication and cambial stem cell behavior.
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Affiliation(s)
- Christoffer Johnsson
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden.
| | - Urs Fischer
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden.
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68
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Immanen J, Nieminen K, Smolander OP, Kojima M, Alonso Serra J, Koskinen P, Zhang J, Elo A, Mähönen AP, Street N, Bhalerao RP, Paulin L, Auvinen P, Sakakibara H, Helariutta Y. Cytokinin and Auxin Display Distinct but Interconnected Distribution and Signaling Profiles to Stimulate Cambial Activity. Curr Biol 2016; 26:1990-1997. [PMID: 27426519 DOI: 10.1016/j.cub.2016.05.053] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Revised: 04/14/2016] [Accepted: 05/23/2016] [Indexed: 01/12/2023]
Abstract
Despite the crucial roles of phytohormones in plant development, comparison of the exact distribution profiles of different hormones within plant meristems has thus far remained scarce. Vascular cambium, a wide lateral meristem with an extensive developmental zonation, provides an optimal system for hormonal and genetic profiling. By taking advantage of this spatial resolution, we show here that two major phytohormones, cytokinin and auxin, display different yet partially overlapping distribution profiles across the cambium. In contrast to auxin, which has its highest concentration in the actively dividing cambial cells, cytokinins peak in the developing phloem tissue of a Populus trichocarpa stem. Gene expression patterns of cytokinin biosynthetic and signaling genes coincided with this hormonal gradient. To explore the functional significance of cytokinin signaling for cambial development, we engineered transgenic Populus tremula × tremuloides trees with an elevated cytokinin biosynthesis level. Confirming that cytokinins function as major regulators of cambial activity, these trees displayed stimulated cambial cell division activity resulting in dramatically increased (up to 80% in dry weight) production of the lignocellulosic trunk biomass. To connect the increased growth to hormonal status, we analyzed the hormone distribution and genome-wide gene expression profiles in unprecedentedly high resolution across the cambial zone. Interestingly, in addition to showing an elevated cambial cytokinin content and signaling level, the cambial auxin concentration and auxin-responsive gene expression were also increased in the transgenic trees. Our results indicate that cytokinin signaling specifies meristematic activity through a graded distribution that influences the amplitude of the cambial auxin gradient.
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Affiliation(s)
- Juha Immanen
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland; Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland
| | - Kaisa Nieminen
- Green Technology, Natural Resources Institute Finland (Luke), Jokiniemenkuja 1, 01301 Vantaa, Finland.
| | | | - Mikiko Kojima
- RIKEN Center for Sustainable Resource Science, 1-7-22, Suehiro, Tsurumi, Yokohama 230-0045, Japan
| | - Juan Alonso Serra
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland; Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland
| | - Patrik Koskinen
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Jing Zhang
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland; Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland; Sainsbury Laboratory, Cambridge University, Bateman Street, Cambridge CB2 1LR, UK
| | - Annakaisa Elo
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland; Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland
| | - Ari Pekka Mähönen
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland; Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland
| | - Nathaniel Street
- Umeå Plant Science Center and Department of Forest Genetics and Plant Physiology, SLU, Umeå 901 87, Sweden
| | - Rishikesh P Bhalerao
- Umeå Plant Science Center and Department of Forest Genetics and Plant Physiology, SLU, Umeå 901 87, Sweden; Department of Biology, King Saud University, Riyadh 11451, Saudi Arabia
| | - Lars Paulin
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Petri Auvinen
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Hitoshi Sakakibara
- RIKEN Center for Sustainable Resource Science, 1-7-22, Suehiro, Tsurumi, Yokohama 230-0045, Japan
| | - Ykä Helariutta
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland; Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland; Sainsbury Laboratory, Cambridge University, Bateman Street, Cambridge CB2 1LR, UK.
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69
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Dun X, Tao Z, Wang J, Wang X, Liu G, Wang H. Comparative Transcriptome Analysis of Primary Roots of Brassica napus Seedlings with Extremely Different Primary Root Lengths Using RNA Sequencing. FRONTIERS IN PLANT SCIENCE 2016; 7:1238. [PMID: 27594860 PMCID: PMC4990598 DOI: 10.3389/fpls.2016.01238] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/04/2016] [Indexed: 05/18/2023]
Abstract
Primary root (PR) development is a crucial developmental process that is essential for plant survival. The elucidation of the PR transcriptome provides insight into the genetic mechanism controlling PR development in crops. In this study, we performed a comparative transcriptome analysis to investigate the genome-wide gene expression profiles of the seedling PRs of four Brassica napus genotypes that were divided into two groups, short group (D43 and D61), and long group (D69 and D72), according to their extremely different primary root lengths (PRLs). The results generated 55,341,366-64,631,336 clean reads aligned to 62,562 genes (61.9% of the current annotated genes) in the B. napus genome. We provide evidence that at least 44,986 genes are actively expressed in the B. napus PR. The majority of the genes that were expressed during seedling PR development were associated with metabolism, cellular processes, response to stimulus, biological regulation, and signaling. Using a pairwise comparison approach, 509 differentially expressed genes (DEGs; absolute value of log2 fold-change ≥1 and p ≤ 0.05) between the long and short groups were revealed, including phytohormone-related genes, protein kinases and phosphatases, oxygenase, cytochrome P450 proteins, etc. Combining GO functional category, KEGG, and MapMan pathway analyses indicated that the DEGs involved in cell wall metabolism, carbohydrate metabolism, lipid metabolism, secondary metabolism, protein modification and degradation, hormone pathways and signaling pathways were the main causes of the observed PRL differences. We also identified 16 differentially expressed transcription factors (TFs) involved in PR development. Taken together, these transcriptomic datasets may serve as a foundation for the identification of candidate genes and may provide valuable information for understanding the molecular and cellular events related to PR development.
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