151
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Wang D, Cao G, Fang P, Xia L, Cheng B. Comparative transcription analysis of different Antirrhinum phyllotaxy nodes identifies major signal networks involved in vegetative-reproductive transition. PLoS One 2017; 12:e0178424. [PMID: 28570685 PMCID: PMC5453694 DOI: 10.1371/journal.pone.0178424] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 05/12/2017] [Indexed: 12/31/2022] Open
Abstract
Vegetative-reproductive phase change is an indispensable event which guarantees several aspects of successful meristem behaviour and organ development. Antirrhinum majus undergoes drastic changes of shoot architecture during the phase change, including phyllotactic change and leaf type alteration from opposite decussate to spiral. However, the regulation mechanism in both of phyllotactic morphology changes is still unclear. Here, the Solexa/Illumina RNA-seq high-throughput sequencing was used to evaluate the global changes of transcriptome levels among four node regions during phyllotactic development. More than 86,315,782 high quality reads were sequenced and assembled into 58,509 unigenes. These differentially expressed genes (DEGs) were classified into 118 pathways described in the KEGG database. Based on the heat-map analysis, a large number of DEGs were overwhelmingly distributed in the hormone signal pathway as well as the carbohydrate biosynthesis and metabolism. The quantitative real time (qRT)-PCR results indicated that most of DEGs were highly up-regulated in the swapping regions of phyllotactic morphology. Moreover, transcriptions factors (TFs) with high transcripts were also identified, controlling the phyllotactic morphology by the regulation of hormone and sugar-metabolism signal pathways. A number of DEGs did not align with any databases and might be novel genes involved in the phyllotactic development. These genes will serve as an invaluable genetic resource for understanding the molecular mechanism of the phyllotactic development.
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Affiliation(s)
- Dongliang Wang
- School of Horticulture, Anhui Agricultural University, Hefei, China
| | - Geyang Cao
- School of Horticulture, Anhui Agricultural University, Hefei, China
| | - Peng Fang
- School of Horticulture, Anhui Agricultural University, Hefei, China
| | - Lin Xia
- School of Horticulture, Anhui Agricultural University, Hefei, China
| | - Beijiu Cheng
- Key Laboratory of Crop Biology of Anhui Province, Anhui Agricultural University, Hefei, China
- * E-mail:
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152
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Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch. Nat Genet 2017; 49:904-912. [PMID: 28481341 DOI: 10.1038/ng.3862] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 04/12/2017] [Indexed: 12/26/2022]
Abstract
Silver birch (Betula pendula) is a pioneer boreal tree that can be induced to flower within 1 year. Its rapid life cycle, small (440-Mb) genome, and advanced germplasm resources make birch an attractive model for forest biotechnology. We assembled and chromosomally anchored the nuclear genome of an inbred B. pendula individual. Gene duplicates from the paleohexaploid event were enriched for transcriptional regulation, whereas tandem duplicates were overrepresented by environmental responses. Population resequencing of 80 individuals showed effective population size crashes at major points of climatic upheaval. Selective sweeps were enriched among polyploid duplicates encoding key developmental and physiological triggering functions, suggesting that local adaptation has tuned the timing of and cross-talk between fundamental plant processes. Variation around the tightly-linked light response genes PHYC and FRS10 correlated with latitude and longitude and temperature, and with precipitation for PHYC. Similar associations characterized the growth-promoting cytokinin response regulator ARR1, and the wood development genes KAK and MED5A.
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153
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Edlund E, Novak O, Karady M, Ljung K, Jansson S. Contrasting patterns of cytokinins between years in senescing aspen leaves. PLANT, CELL & ENVIRONMENT 2017; 40:622-634. [PMID: 28042677 DOI: 10.1111/pce.12899] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 11/01/2016] [Accepted: 11/01/2016] [Indexed: 05/05/2023]
Abstract
Cytokinins are plant hormones that typically block or delay leaf senescence. We profiled 34 different cytokinins/cytokinin metabolites (including precursors, conjugates and degradation products) in leaves of a free-growing mature aspen (Populus tremula) before and after the initiation of autumnal senescence over three consecutive years. The levels and profiles of individual cytokinin species, or classes/groups, varied greatly between years, despite the fact that the onset of autumn senescence was at the same time each year, and senescence was not associated with depletion of either active or total cytokinin levels. Levels of aromatic cytokinins (topolins) were low and changed little over the autumn period. Diurnal variations and weather-dependent variations in cytokinin content were relatively limited. We also followed the expression patterns of all aspen genes implicated as having roles in cytokinin metabolism or signalling, but neither the pattern of regulation of any group of genes nor the expression of any particular gene supported the notion that decreased cytokinin signalling could explain the onset of senescence. Based on the results from this tree, we therefore suggest that cytokinin depletion is unlikely to explain the onset of autumn leaf senescence in aspen.
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Affiliation(s)
- Erik Edlund
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, 901 87, Sweden
| | - Ondrej Novak
- Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany CAS and Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc, CZ-78371, Czech Republic
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, 901 83, Sweden
| | - Michal Karady
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, 901 83, Sweden
| | - Karin Ljung
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, 901 83, Sweden
| | - Stefan Jansson
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, 901 87, Sweden
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154
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Yamburenko MV, Kieber JJ, Schaller GE. Dynamic patterns of expression for genes regulating cytokinin metabolism and signaling during rice inflorescence development. PLoS One 2017; 12:e0176060. [PMID: 28419168 PMCID: PMC5395194 DOI: 10.1371/journal.pone.0176060] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 04/04/2017] [Indexed: 11/18/2022] Open
Abstract
Inflorescence development in cereals, including such important crops as rice, maize, and wheat, directly affects grain number and size and is a key determinant of yield. Cytokinin regulates meristem size and activity and, as a result, has profound effects on inflorescence development and architecture. To clarify the role of cytokinin action in inflorescence development, we used the NanoString nCounter system to analyze gene expression in the early stages of rice panicle development, focusing on 67 genes involved in cytokinin biosynthesis, degradation, and signaling. Results point toward key members of these gene families involved in panicle development and indicate that the expression of many genes involved in cytokinin action differs between the panicle and vegetative tissues. Dynamic patterns of gene expression suggest that subnetworks mediate cytokinin action during different stages of panicle development. The variation of expression during panicle development is greater among genes encoding proteins involved in cytokinin metabolism and negative regulators of the pathway than for the genes in the primary response pathway. These results provide insight into the expression patterns of genes involved in cytokinin action during inflorescence development in a crop of agricultural importance, with relevance to similar processes in other monocots. The identification of subnetworks of genes expressed at different stages of early panicle development suggests that manipulation of their expression could have substantial effects on inflorescence architecture.
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Affiliation(s)
- Maria V. Yamburenko
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Joseph J. Kieber
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - G. Eric Schaller
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, United States of America
- * E-mail:
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155
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Reyes-Olalde JI, Zúñiga-Mayo VM, Serwatowska J, Chavez Montes RA, Lozano-Sotomayor P, Herrera-Ubaldo H, Gonzalez-Aguilera KL, Ballester P, Ripoll JJ, Ezquer I, Paolo D, Heyl A, Colombo L, Yanofsky MF, Ferrandiz C, Marsch-Martínez N, de Folter S. The bHLH transcription factor SPATULA enables cytokinin signaling, and both activate auxin biosynthesis and transport genes at the medial domain of the gynoecium. PLoS Genet 2017; 13:e1006726. [PMID: 28388635 PMCID: PMC5400277 DOI: 10.1371/journal.pgen.1006726] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 04/21/2017] [Accepted: 03/30/2017] [Indexed: 11/18/2022] Open
Abstract
Fruits and seeds are the major food source on earth. Both derive from the gynoecium and, therefore, it is crucial to understand the mechanisms that guide the development of this organ of angiosperm species. In Arabidopsis, the gynoecium is composed of two congenitally fused carpels, where two domains: medial and lateral, can be distinguished. The medial domain includes the carpel margin meristem (CMM) that is key for the production of the internal tissues involved in fertilization, such as septum, ovules, and transmitting tract. Interestingly, the medial domain shows a high cytokinin signaling output, in contrast to the lateral domain, where it is hardly detected. While it is known that cytokinin provides meristematic properties, understanding on the mechanisms that underlie the cytokinin signaling pattern in the young gynoecium is lacking. Moreover, in other tissues, the cytokinin pathway is often connected to the auxin pathway, but we also lack knowledge about these connections in the young gynoecium. Our results reveal that cytokinin signaling, that can provide meristematic properties required for CMM activity and growth, is enabled by the transcription factor SPATULA (SPT) in the medial domain. Meanwhile, cytokinin signaling is confined to the medial domain by the cytokinin response repressor ARABIDOPSIS HISTIDINE PHOSPHOTRANSFERASE 6 (AHP6), and perhaps by ARR16 (a type-A ARR) as well, both present in the lateral domains (presumptive valves) of the developing gynoecia. Moreover, SPT and cytokinin, probably together, promote the expression of the auxin biosynthetic gene TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS 1 (TAA1) and the gene encoding the auxin efflux transporter PIN-FORMED 3 (PIN3), likely creating auxin drainage important for gynoecium growth. This study provides novel insights in the spatiotemporal determination of the cytokinin signaling pattern and its connection to the auxin pathway in the young gynoecium.
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Affiliation(s)
- J. Irepan Reyes-Olalde
- Unidad de Genómica Avanzada (LANGEBIO), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Irapuato, Guanajuato, México
| | - Víctor M. Zúñiga-Mayo
- Unidad de Genómica Avanzada (LANGEBIO), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Irapuato, Guanajuato, México
| | - Joanna Serwatowska
- Unidad de Genómica Avanzada (LANGEBIO), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Irapuato, Guanajuato, México
| | - Ricardo A. Chavez Montes
- Unidad de Genómica Avanzada (LANGEBIO), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Irapuato, Guanajuato, México
| | - Paulina Lozano-Sotomayor
- Unidad de Genómica Avanzada (LANGEBIO), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Irapuato, Guanajuato, México
| | - Humberto Herrera-Ubaldo
- Unidad de Genómica Avanzada (LANGEBIO), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Irapuato, Guanajuato, México
| | - Karla L. Gonzalez-Aguilera
- Unidad de Genómica Avanzada (LANGEBIO), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Irapuato, Guanajuato, México
| | - Patricia Ballester
- Instituto de Biología Molecular y Celular de Plantas, CSIC-UPV Universidad Politécnica de Valencia, Valencia, Spain
| | - Juan José Ripoll
- Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
| | - Ignacio Ezquer
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Dario Paolo
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Alexander Heyl
- Biology Department, Adelphi University, Garden City, New York, United States of America
| | - Lucia Colombo
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Martin F. Yanofsky
- Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
| | - Cristina Ferrandiz
- Instituto de Biología Molecular y Celular de Plantas, CSIC-UPV Universidad Politécnica de Valencia, Valencia, Spain
| | | | - Stefan de Folter
- Unidad de Genómica Avanzada (LANGEBIO), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Irapuato, Guanajuato, México
- * E-mail:
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156
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Wang J, Jiang L, Wu R. Plant grafting: how genetic exchange promotes vascular reconnection. THE NEW PHYTOLOGIST 2017; 214:56-65. [PMID: 27991666 DOI: 10.1111/nph.14383] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 11/13/2016] [Indexed: 05/17/2023]
Abstract
Grafting has been widely used to improve horticultural traits. It has also served increasingly as a tool to investigate the long-distance transport of molecules that is an essential part for key biological processes. Many studies have revealed the molecular mechanisms of graft-induced phenotypic variation in anatomy, morphology and production. Here, we review the phenomena and their underlying mechanisms by which macromolecules, including RNA, protein, and even DNA, are transported between scions and rootstocks via vascular tissues. We further propose a conceptual framework that characterizes and quantifies the driving mechanisms of scion-rootstock interactions toward vascular reconnection and regeneration.
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Affiliation(s)
- Jing Wang
- Center for Computational Biology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Libo Jiang
- Center for Computational Biology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Rongling Wu
- Center for Computational Biology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
- Center for Statistical Genetics, Pennsylvania State University, Hershey, PA, 17033, USA
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157
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Iakimova ET, Woltering EJ. Xylogenesis in zinnia (Zinnia elegans) cell cultures: unravelling the regulatory steps in a complex developmental programmed cell death event. PLANTA 2017; 245:681-705. [PMID: 28194564 PMCID: PMC5357506 DOI: 10.1007/s00425-017-2656-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 01/27/2017] [Indexed: 05/20/2023]
Abstract
MAIN CONCLUSION Physiological and molecular studies support the view that xylogenesis can largely be determined as a specific form of vacuolar programmed cell death (PCD). The studies in xylogenic zinnia cell culture have led to many breakthroughs in xylogenesis research and provided a background for investigations in other experimental models in vitro and in planta . This review discusses the most essential earlier and recent findings on the regulation of xylem elements differentiation and PCD in zinnia and other xylogenic systems. Xylogenesis (the formation of water conducting vascular tissue) is a paradigm of plant developmental PCD. The xylem vessels are composed of fused tracheary elements (TEs)-dead, hollow cells with patterned lignified secondary cell walls. They result from the differentiation of the procambium and cambium cells and undergo cell death to become functional post-mortem. The TE differentiation proceeds through a well-coordinated sequence of events in which differentiation and the programmed cellular demise are intimately connected. For years a classical experimental model for studies on xylogenesis was the xylogenic zinnia (Zinnia elegans) cell culture derived from leaf mesophyll cells that, upon induction by cytokinin and auxin, transdifferentiate into TEs. This cell system has been proven very efficient for investigations on the regulatory components of xylem differentiation which has led to many discoveries on the mechanisms of xylogenesis. The knowledge gained from this system has potentiated studies in other xylogenic cultures in vitro and in planta. The present review summarises the previous and latest findings on the hormonal and biochemical signalling, metabolic pathways and molecular and gene determinants underlying the regulation of xylem vessels differentiation in zinnia cell culture. Highlighted are breakthroughs achieved through the use of xylogenic systems from other species and newly introduced tools and analytical approaches to study the processes. The mutual dependence between PCD signalling and the differentiation cascade in the program of TE development is discussed.
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Affiliation(s)
| | - Ernst J Woltering
- Wageningen University and Research, Food and Biobased Research, P.O. Box 17, 6700 AA, Wageningen, The Netherlands.
- Wageningen University, Horticulture and Product Physiology, P.O. Box 630, 6700 AP, Wageningen, The Netherlands.
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158
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Oles V, Panchenko A, Smertenko A. Modeling hormonal control of cambium proliferation. PLoS One 2017; 12:e0171927. [PMID: 28187161 PMCID: PMC5302410 DOI: 10.1371/journal.pone.0171927] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 01/29/2017] [Indexed: 12/14/2022] Open
Abstract
Rise of atmospheric CO2 is one of the main causes of global warming. Catastrophic climate change can be avoided by reducing emissions and increasing sequestration of CO2. Trees are known to sequester CO2 during photosynthesis, and then store it as wood biomass. Thus, breeding of trees with higher wood yield would mitigate global warming as well as augment production of renewable construction materials, energy, and industrial feedstock. Wood is made of cellulose-rich xylem cells produced through proliferation of a specialized stem cell niche called cambium. Importance of cambium in xylem cells production makes it an ideal target for the tree breeding programs; however our knowledge about control of cambium proliferation remains limited. The morphology and regulation of cambium are different from those of stem cell niches that control axial growth. For this reason, translating the knowledge about axial growth to radial growth has limited use. Furthermore, genetic approaches cannot be easily applied because overlaying tissues conceal cambium from direct observation and complicate identification of mutants. To overcome the paucity of experimental tools in cambium biology, we constructed a Boolean network CARENET (CAmbium REgulation gene NETwork) for modelling cambium activity, which includes the key transcription factors WOX4 and HD-ZIP III as well as their potential regulators. Our simulations predict that: (1) auxin, cytokinin, gibberellin, and brassinosteroids act cooperatively in promoting transcription of WOX4 and HD-ZIP III; (2) auxin and cytokinin pathways negatively regulate each other; (3) hormonal pathways act redundantly in sustaining cambium activity; (4) individual cambium cells can have diverse molecular identities. CARENET can be extended to include components of other signalling pathways and be integrated with models of xylem and phloem differentiation. Such extended models would facilitate breeding trees with higher wood yield.
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Affiliation(s)
- Vladyslav Oles
- Department of Mathematics, Washington State University, Pullman, Washington, United States of America
| | - Alexander Panchenko
- Department of Mathematics, Washington State University, Pullman, Washington, United States of America
- * E-mail: (AP); (AS)
| | - Andrei Smertenko
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, United States of America
- * E-mail: (AP); (AS)
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159
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Heo JO, Blob B, Helariutta Y. Differentiation of conductive cells: a matter of life and death. CURRENT OPINION IN PLANT BIOLOGY 2017; 35:23-29. [PMID: 27794261 DOI: 10.1016/j.pbi.2016.10.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 10/11/2016] [Accepted: 10/13/2016] [Indexed: 05/26/2023]
Abstract
Two major conducting tissues in plants, phloem and xylem, are composed of highly specialized cell types adapted to long distance transport. Sieve elements (SEs) in the phloem display a thick cell wall, callose-rich sieve plates and low cytoplasmic density. SE differentiation is driven by selective autolysis combined with enucleation, after which the plasma membrane and some organelles are retained. By contrast, differentiation of xylem tracheary elements (TEs) involves complete clearance of the cellular components by programmed cell death followed by autolysis of the protoplast; this is accompanied by extensive deposition of lignin and cellulose in the cell wall. Emerging molecular data on TE and SE differentiation indicate a central role for NAC and MYB type transcription factors in both processes.
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Affiliation(s)
- Jung-Ok Heo
- Sainsbury Laboratory, Cambridge University, Bateman Street, Cambridge CB2 1LR, UK; Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Bernhard Blob
- Sainsbury Laboratory, Cambridge University, Bateman Street, Cambridge CB2 1LR, UK
| | - Ykä Helariutta
- Sainsbury Laboratory, Cambridge University, Bateman Street, Cambridge CB2 1LR, UK; Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland.
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160
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Alabdallah O, Ahou A, Mancuso N, Pompili V, Macone A, Pashkoulov D, Stano P, Cona A, Angelini R, Tavladoraki P. The Arabidopsis polyamine oxidase/dehydrogenase 5 interferes with cytokinin and auxin signaling pathways to control xylem differentiation. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:997-1012. [PMID: 28199662 DOI: 10.1093/jxb/erw510] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In plants, the polyamines putrescine, spermidine, spermine (Spm), and thermospermine (Therm-Spm) participate in several physiological processes. In particular, Therm-Spm is involved in the control of xylem differentiation, having an auxin antagonizing effect. Polyamine oxidases (PAOs) are FAD-dependent enzymes involved in polyamine catabolism. In Arabidopsis, five PAOs are present, among which AtPAO5 catalyzes the back-conversion of Spm, Therm-Spm, and N1-acetyl-Spm to spermidine. In the present study, it is shown that two loss-of-function atpao5 mutants and a 35S::AtPAO5 Arabidopsis transgenic line present phenotypical differences from the wild-type plants with regard to stem and root elongation, differences that are accompanied by changes in polyamine levels and the number of xylem vessels. It is additionally shown that cytokinin treatment, which up-regulates AtPAO5 expression in roots, differentially affects protoxylem differentiation in 35S::AtPAO5, atpao5, and wild-type roots. Together with these findings, Therm-Spm biosynthetic genes, as well as auxin-, xylem-, and cytokinin-related genes (such as ACL5, SAMDC4, PIN1, PIN6, VND6, VND7, ATHB8, PHB, CNA, PXY, XTH3, XCP1, and AHP6) are shown to be differentially expressed in the various genotypes. These data suggest that AtPAO5, being involved in the control of Therm-Spm homeostasis, participates in the tightly controlled interplay between auxin and cytokinins that is necessary for proper xylem differentiation.
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Affiliation(s)
| | - Abdellah Ahou
- Department of Sciences, University 'ROMA TRE', Rome, Italy
| | | | | | - Alberto Macone
- Department of Biochemical Sciences 'A. Rossi Fanelli', University of Rome 'La Sapienza', Rome, Italy
| | - Dimitre Pashkoulov
- Società Agricola Floramiata Servizi srl, 53025 Piancastagnaio, Siena, Italy
| | - Pasquale Stano
- Department of Sciences, University 'ROMA TRE', Rome, Italy
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161
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Cho H, Dang TVT, Hwang I. Emergence of plant vascular system: roles of hormonal and non-hormonal regulatory networks. CURRENT OPINION IN PLANT BIOLOGY 2017; 35:91-97. [PMID: 27918941 DOI: 10.1016/j.pbi.2016.11.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 11/16/2016] [Accepted: 11/22/2016] [Indexed: 06/06/2023]
Abstract
The divergence of land plants followed by vascular plants has entirely changed the terrestrial ecology. The vascular system is a prerequisite for this evolutionary event, providing upright stature and communication for sink demand-source capacity and facilitating the development of plants and colonization over a wide range of environmental habitats. Various hormonal and non-hormonal regulatory networks have been identified and reviewed as key processes for vascular formation; however, how these factors have evolutionarily emerged and interconnected to trigger the emergence of the vascular system still remains elusive. Here, to understand the intricacy of cross-talks among these factors, we highlight how core hormonal signaling and transcriptional networks are coalesced into the appearance of vascular plants during evolution.
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Affiliation(s)
- Hyunwoo Cho
- Department of Life Sciences, POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Tuong Vi T Dang
- Department of Life Sciences, POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Ildoo Hwang
- Department of Life Sciences, POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea.
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162
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Ramachandran P, Carlsbecker A, Etchells JP. Class III HD-ZIPs govern vascular cell fate: an HD view on patterning and differentiation. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:55-69. [PMID: 27794018 DOI: 10.1093/jxb/erw370] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Plant vasculature is required for the transport of water and solutes throughout the plant body. It is constituted of xylem, specialized for transport of water, and phloem, that transports photosynthates. These two differentiated tissues are specified early in development and arise from divisions in the procambium, which is the vascular meristem during primary growth. During secondary growth, the xylem and phloem are further expanded via differentiation of cells derived from divisions in the cambium. Almost all of the developmental fate decisions in this process, including vascular specification, patterning, and differentiation, are regulated by transcription factors belonging to the class III homeodomain-leucine zipper (HD-ZIP III) family. This review draws together the literature describing the roles that these genes play in vascular development, looking at how HD-ZIP IIIs are regulated, and how they in turn influence other regulators of vascular development. Themes covered vary, from interactions between HD-ZIP IIIs and auxin, cytokinin, and brassinosteroids, to the requirement for exquisite spatial and temporal regulation of HD-ZIP III expression through miRNA-mediated post-transcriptional regulation, and interactions with other transcription factors. The literature described places the HD-ZIP III family at the centre of a complex network required for initiating and maintaining plant vascular tissues.
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Affiliation(s)
- Prashanth Ramachandran
- Physiological Botany, Department of Organismal Biology and Linnean Centre for Plant Biology in Uppsala, Uppsala University, Ulls väg 24E, SE-756 51 Uppsala, Sweden
| | - Annelie Carlsbecker
- Physiological Botany, Department of Organismal Biology and Linnean Centre for Plant Biology in Uppsala, Uppsala University, Ulls väg 24E, SE-756 51 Uppsala, Sweden
| | - J Peter Etchells
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
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163
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Abstract
The history of auxin and cytokinin biology including the initial discoveries by father-son duo Charles Darwin and Francis Darwin (1880), and Gottlieb Haberlandt (1919) is a beautiful demonstration of unceasing continuity of research. Novel findings are integrated into existing hypotheses and models and deepen our understanding of biological principles. At the same time new questions are triggered and hand to hand with this new methodologies are developed to address these new challenges.
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Affiliation(s)
- Andrej Hurný
- Institute of Science and Technology, Am Campus 1, 3400, Klosterneuburg, Austria
| | - Eva Benková
- Institute of Science and Technology, Am Campus 1, 3400, Klosterneuburg, Austria.
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164
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Etchells JP, Turner SR. Realizing pipe dreams - a detailed picture of vascular development. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:1-4. [PMID: 28013229 PMCID: PMC5183087 DOI: 10.1093/jxb/erw482] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Affiliation(s)
- J Peter Etchells
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK,
| | - Simon R Turner
- Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester M13 9PT, UK
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165
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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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166
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Mellor N, Adibi M, El-Showk S, De Rybel B, King J, Mähönen AP, Weijers D, Bishopp A. Theoretical approaches to understanding root vascular patterning: a consensus between recent models. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:5-16. [PMID: 27837006 DOI: 10.1093/jxb/erw410] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The root vascular tissues provide an excellent system for studying organ patterning, as the specification of these tissues signals a transition from radial symmetry to bisymmetric patterns. The patterning process is controlled by the combined action of hormonal signaling/transport pathways, transcription factors, and miRNA that operate through a series of non-linear pathways to drive pattern formation collectively. With the discovery of multiple components and feedback loops controlling patterning, it has become increasingly difficult to understand how these interactions act in unison to determine pattern formation in multicellular tissues. Three independent mathematical models of root vascular patterning have been formulated in the last few years, providing an excellent example of how theoretical approaches can complement experimental studies to provide new insights into complex systems. In many aspects these models support each other; however, each study also provides its own novel findings and unique viewpoints. Here we reconcile these models by identifying the commonalities and exploring the differences between them by testing how transferable findings are between models. New simulations herein support the hypothesis that an asymmetry in auxin input can direct the formation of vascular pattern. We show that the xylem axis can act as a sole source of cytokinin and specify the correct pattern, but also that broader patterns of cytokinin production are also able to pattern the root. By comparing the three modeling approaches, we gain further insight into vascular patterning and identify several key areas for experimental investigation.
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Affiliation(s)
- Nathan Mellor
- Centre for Plant Integrative Biology, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Milad Adibi
- Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Sedeer El-Showk
- Institute of Biotechnology, University of Helsinki, Helsinki FIN-00014, Finland
- Department of Biosciences, Viikki Plant Science Centre, University of Helsinki, Helsinki FIN-00014, Finland
| | - Bert De Rybel
- Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708WE Wageningen, The Netherlands
- Department of Plant Systems Biology, VIB, Technologiepark 927, B-9052, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, VIB, Technologiepark 927, B-9052, Ghent, Belgium
| | - John King
- Centre for Plant Integrative Biology, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
- School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, UK
- Synthetic Biology Research Centre, The University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Ari Pekka Mähönen
- Institute of Biotechnology, University of Helsinki, Helsinki FIN-00014, Finland
- Department of Biosciences, Viikki Plant Science Centre, University of Helsinki, Helsinki FIN-00014, Finland
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708WE Wageningen, The Netherlands
| | - Anthony Bishopp
- Centre for Plant Integrative Biology, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
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167
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Frerichs A, Thoma R, Abdallah AT, Frommolt P, Werr W, Chandler JW. The founder-cell transcriptome in the Arabidopsis apetala1 cauliflower inflorescence meristem. BMC Genomics 2016; 17:855. [PMID: 27809788 PMCID: PMC5093967 DOI: 10.1186/s12864-016-3189-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 10/22/2016] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Although the pattern of lateral organ formation from apical meristems establishes species-specific plant architecture, the positional information that confers cell fate to cells as they transit to the meristem flanks where they differentiate, remains largely unknown. We have combined fluorescence-activated cell sorting and RNA-seq to characterise the cell-type-specific transcriptome at the earliest developmental time-point of lateral organ formation using DORNRÖSCHEN-LIKE::GFP to mark founder-cell populations at the periphery of the inflorescence meristem (IM) in apetala1 cauliflower double mutants, which overproliferate IMs. RESULTS Within the lateral organ founder-cell population at the inflorescence meristem, floral primordium identity genes are upregulated and stem-cell identity markers are downregulated. Additional differentially expressed transcripts are involved in polarity generation and boundary formation, and in epigenetic and post-translational changes. However, only subtle transcriptional reprogramming within the global auxin network was observed. CONCLUSIONS The transcriptional network of differentially expressed genes supports the hypothesis that lateral organ founder-cell specification involves the creation of polarity from the centre to the periphery of the IM and the establishment of a boundary from surrounding cells, consistent with bract initiation. However, contrary to the established paradigm that sites of auxin response maxima pre-pattern lateral organ initiation in the IM, auxin response might play a minor role in the earliest stages of lateral floral initiation.
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Affiliation(s)
- Anneke Frerichs
- Institute of Developmental Biology, University of Cologne, Cologne Biocenter, Zuelpicher Strasse 47b, D-50674, Cologne, Germany
| | - Rahere Thoma
- Present address: Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829, Cologne, Germany
| | - Ali Taleb Abdallah
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931, Cologne, Germany
| | - Peter Frommolt
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931, Cologne, Germany
| | - Wolfgang Werr
- Institute of Developmental Biology, University of Cologne, Cologne Biocenter, Zuelpicher Strasse 47b, D-50674, Cologne, Germany
| | - John William Chandler
- Institute of Developmental Biology, University of Cologne, Cologne Biocenter, Zuelpicher Strasse 47b, D-50674, Cologne, Germany.
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168
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Ohashi-Ito K, Fukuda H. Functional mechanism of bHLH complexes during early vascular development. CURRENT OPINION IN PLANT BIOLOGY 2016; 33:42-47. [PMID: 27314622 DOI: 10.1016/j.pbi.2016.06.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 06/01/2016] [Accepted: 06/01/2016] [Indexed: 05/27/2023]
Abstract
The vascular system spreads throughout the plant body. This highly organized network contains several types of cells. Vascular cell development is initiated during embryogenesis, and then vascular cells proliferate, form a vascular pattern, and commit to specific cell fates. Recent molecular genetics and modeling approaches have increased our understanding of the molecular mechanisms underlying early vascular development. Early events during vascular development are tightly linked and controlled by transcriptional complexes consisting of LONESOME HIGHWAY (LHW) and TARGET OF MONOPTEROS5 (TMO5) families. The role of LHW-TMO5 is tightly coupled with biosynthesis and/or signaling of phytohormones such as auxin and cytokinin. In this review, we discuss the regulatory network mediated by LHW-TMO5 during early vascular development.
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Affiliation(s)
- Kyoko Ohashi-Ito
- Department Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan.
| | - Hiroo Fukuda
- Department Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan.
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169
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Genetic and epigenetic control of transfer cell development in plants. J Genet Genomics 2016; 43:533-539. [PMID: 27618166 DOI: 10.1016/j.jgg.2016.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 07/26/2016] [Accepted: 08/16/2016] [Indexed: 11/22/2022]
Abstract
The inter-cellular translocation of nutrients in plant is mediated by highly specialized transfer cells (TCs). TCs share similar functional and structural features across a wide range of plant species, including location at plant exchange surfaces, rich in secondary wall ingrowths, facilitation of nutrient flow, and passage of select molecules. The fate of endosperm TCs is determined in the TC fate acquisition stage (TCF), before the structure features are formed in the TC differentiation stage (TCD). At present, the molecular basis of TC development in plants remains largely unknown. In this review, we summarize the important roles of the signaling molecules in different development phases, such as sugars in TCF and phytohormones in TCD, and discuss the genetic and epigenetic factors, including TC-specific genes and endogenous plant peptides, and their crosstalk with these signaling molecules as a complex regulatory network in regulation of TC development in plants.
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170
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Abstract
Cytokinin is an essential plant hormone that is involved in a wide range of plant growth and developmental processes which are controlled through its signalling pathway. Cytokinins are a class of molecules that are N(6)-substituted adenine derivatives, such as isopentenyl adenine, and trans- and cis-zeatin, which are common in most plants. The ability to perceive and respond to cytokinin occurs through a modified bacterial two-component pathway that functions via a multi-step phosphorelay. This cytokinin signalling process is a crucial part of almost all stages of plant life, from embryo patterning to apical meristem regulation, organ development and eventually senescence. The cytokinin signalling pathway involves the co-ordination of three types of proteins: histidine kinase receptors to perceive the signal, histidine phosphotransfer proteins to relay the signal, and response regulators to provide signal output. This pathway contains both positive and negative elements that function in a complex co-ordinated manner to control cytokinin-regulated plant responses. Although much is known about how this cytokinin signal is perceived and initially regulated, there are still many avenues that need to be explored before the role of cytokinin in the control of plant processes is fully understood.
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171
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Seeliger I, Frerichs A, Glowa D, Velo L, Comelli P, Chandler JW, Werr W. The AP2-type transcription factors DORNRÖSCHEN and DORNRÖSCHEN-LIKE promote G1/S transition. Mol Genet Genomics 2016; 291:1835-49. [PMID: 27277595 DOI: 10.1007/s00438-016-1224-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 06/03/2016] [Indexed: 11/30/2022]
Abstract
The paralogous genes DORNRÖSCHEN (DRN) and DORNRÖSCHEN-LIKE (DRNL) encode AP2-type transcription factors that are expressed and act cell-autonomously in the central stem-cell zone or lateral organ founder cells (LOFCs) in the peripheral zone of the Arabidopsis shoot meristem (SAM), but their molecular contribution is unknown. Here, we show using the Arabidopsis thaliana MERISTEM LAYER 1 promoter that DRN and DRNL share a common function in cell cycle progression and potentially provide local competence for G1-S transitions in the SAM. Analysis of double transgenic DRN::erGFP and DRNL::erCERULEAN promoter fusion lines suggests that the trajectory of this cellular competence starts with DRN activity in the central stem-cell zone and extends locally via DRNL activity into groups of founder cells at the IM or FM periphery. Our data support the scenario that after gene duplication, DRN and DRNL acquired different transcription domains within the shoot meristem, but retained protein function that affects cell cycle progression, either centrally in stem cells or peripherally in primordial founder cells, a finding that is of general relevance for meristem function.
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Affiliation(s)
- Ingo Seeliger
- Institute of Developmental Biology, Biocenter Cologne, University of Cologne, Zuelpicher Str. 47b, 50674, Cologne, Germany
| | - Anneke Frerichs
- Institute of Developmental Biology, Biocenter Cologne, University of Cologne, Zuelpicher Str. 47b, 50674, Cologne, Germany
| | - Dorothea Glowa
- Institute of Developmental Biology, Biocenter Cologne, University of Cologne, Zuelpicher Str. 47b, 50674, Cologne, Germany
| | - Laura Velo
- Institute of Developmental Biology, Biocenter Cologne, University of Cologne, Zuelpicher Str. 47b, 50674, Cologne, Germany.,Institute of Zoology, Biocenter Cologne, University of Cologne, Zuelpicher Str. 47b, 50674, Cologne, Germany
| | - Petra Comelli
- Institute of Developmental Biology, Biocenter Cologne, University of Cologne, Zuelpicher Str. 47b, 50674, Cologne, Germany
| | - John W Chandler
- Institute of Developmental Biology, Biocenter Cologne, University of Cologne, Zuelpicher Str. 47b, 50674, Cologne, Germany
| | - Wolfgang Werr
- Institute of Developmental Biology, Biocenter Cologne, University of Cologne, Zuelpicher Str. 47b, 50674, Cologne, Germany.
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172
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Abstract
The cultivation of many crops relies on the formation of chimeric plants, where roots from one variety are grafted onto the shoot of another. A new study uncovers how two plants connect and demonstrates that the root and shoot do not contribute equally to the union.
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Affiliation(s)
- Britta M C Kümpers
- Centre of Plant Integrative Plant Biology, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Anthony Bishopp
- Centre of Plant Integrative Plant Biology, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK.
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173
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Zürcher E, Müller B. Cytokinin Synthesis, Signaling, and Function--Advances and New Insights. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 324:1-38. [PMID: 27017005 DOI: 10.1016/bs.ircmb.2016.01.001] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The plant hormones referred to as cytokinins are chemical signals that control numerous developmental processes throughout the plant life cycle, including gametogenesis, root meristem specification, vascular development, shoot and root growth, meristem homeostasis, senescence, and more. In addition, they mediate responses to environmental cues such as light, stress, and nutrient conditions. The core mechanistics of cytokinin metabolism and signaling have been elucidated, but more layers of regulation, additional functions, and interactions with other signals are continuously discovered and described. In this chapter, we recapitulate the highlights of over 100 years of cytokinin research covering its isolation, the elucidation of phosphorelay signaling, and how cytokinin functions in various developmental contexts including its interaction with other pathways. Additionally, given cytokinin's paracrine signaling mechanism, we postulate that cellular exporters for cytokinins exist.
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Affiliation(s)
- E Zürcher
- Department of Plant and Microbial Biology, Zurich-Basel Plant Science Center, University of Zurich Zurich, Switzerland
| | - B Müller
- Department of Plant and Microbial Biology, Zurich-Basel Plant Science Center, University of Zurich Zurich, Switzerland.
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174
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Chemical control of xylem differentiation by thermospermine, xylemin, and auxin. Sci Rep 2016; 6:21487. [PMID: 26879262 PMCID: PMC4754900 DOI: 10.1038/srep21487] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/25/2016] [Indexed: 12/14/2022] Open
Abstract
The xylem conducts water and minerals from the root to the shoot and provides mechanical strength to the plant body. The vascular precursor cells of the procambium differentiate to form continuous vascular strands, from which xylem and phloem cells are generated in the proper spatiotemporal pattern. Procambium formation and xylem differentiation are directed by auxin. In angiosperms, thermospermine, a structural isomer of spermine, suppresses xylem differentiation by limiting auxin signalling. However, the process of auxin-inducible xylem differentiation has not been fully elucidated and remains difficult to manipulate. Here, we found that an antagonist of spermidine can act as an inhibitor of thermospermine biosynthesis and results in excessive xylem differentiation, which is a phenocopy of a thermospermine-deficient mutant acaulis5 in Arabidopsis thaliana. We named this compound xylemin owing to its xylem-inducing effect. Application of a combination of xylemin and thermospermine to wild-type seedlings negates the effect of xylemin, whereas co-treatment with xylemin and a synthetic proauxin, which undergoes hydrolysis to release active auxin, has a synergistic inductive effect on xylem differentiation. Thus, xylemin may serve as a useful transformative chemical tool not only for the study of thermospermine function in various plant species but also for the control of xylem induction and woody biomass production.
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175
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Adibi M, Yoshida S, Weijers D, Fleck C. Centering the Organizing Center in the Arabidopsis thaliana Shoot Apical Meristem by a Combination of Cytokinin Signaling and Self-Organization. PLoS One 2016; 11:e0147830. [PMID: 26872130 PMCID: PMC4752473 DOI: 10.1371/journal.pone.0147830] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 01/08/2016] [Indexed: 12/15/2022] Open
Abstract
Plants have the ability to continously generate new organs by maintaining populations of stem cells throught their lives. The shoot apical meristem (SAM) provides a stable environment for the maintenance of stem cells. All cells inside the SAM divide, yet boundaries and patterns are maintained. Experimental evidence indicates that patterning is independent of cell lineage, thus a dynamic self-regulatory mechanism is required. A pivotal role in the organization of the SAM is played by the WUSCHEL gene (WUS). An important question in this regard is that how WUS expression is positioned in the SAM via a cell-lineage independent signaling mechanism. In this study we demonstrate via mathematical modeling that a combination of an inhibitor of the Cytokinin (CK) receptor, Arabidopsis histidine kinase 4 (AHK4) and two morphogens originating from the top cell layer, can plausibly account for the cell lineage-independent centering of WUS expression within SAM. Furthermore, our laser ablation and microsurgical experiments support the hypothesis that patterning in SAM occurs at the level of CK reception and signaling. The model suggests that the interplay between CK signaling, WUS/CLV feedback loop and boundary signals can account for positioning of the WUS expression, and provides directions for further experimental investigation.
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Affiliation(s)
- Milad Adibi
- Laboratory of Systems and Synthetic Biology, Wageningen University, Wageningen, the Netherlands
- * E-mail: (MA); (CF)
| | - Saiko Yoshida
- Laboratory of Biochemistry, Wageningen University, Wageningen, the Netherlands
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, Wageningen, the Netherlands
| | - Christian Fleck
- Laboratory of Systems and Synthetic Biology, Wageningen University, Wageningen, the Netherlands
- * E-mail: (MA); (CF)
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176
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Fisher AP, Sozzani R. Uncovering the networks involved in stem cell maintenance and asymmetric cell division in the Arabidopsis root. CURRENT OPINION IN PLANT BIOLOGY 2016; 29:38-43. [PMID: 26707611 DOI: 10.1016/j.pbi.2015.11.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 11/02/2015] [Accepted: 11/04/2015] [Indexed: 06/05/2023]
Abstract
Stem cells are the source of different cell types and tissues in all multicellular organisms. In plants, the balance between stem cell self-renewal and differentiation of their progeny is crucial for correct tissue and organ formation. How transcriptional programs precisely control stem cell maintenance and identity, and what are the regulatory programs influencing stem cell asymmetric cell division (ACD), are key questions that researchers have sought to address for the past decade. Successful efforts in genetic, molecular, and developmental biology, along with mathematical modeling, have identified some of the players involved in stem cell regulation. In this review, we will discuss several studies that characterized many of the genetic programs and molecular mechanisms regulating stem cell ACD and their identity in the Arabidopsis root. We will also highlight how the growing use of mathematical modeling provides a comprehensive and quantitative perspective on the design rules governing stem cell ACDs.
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Affiliation(s)
- Adam P Fisher
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, United States
| | - Rosangela Sozzani
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, United States.
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177
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Surujon D, Ratner DI. Use of a Probabilistic Motif Search to Identify Histidine Phosphotransfer Domain-Containing Proteins. PLoS One 2016; 11:e0146577. [PMID: 26751210 PMCID: PMC4709007 DOI: 10.1371/journal.pone.0146577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 12/18/2015] [Indexed: 11/18/2022] Open
Abstract
The wealth of newly obtained proteomic information affords researchers the possibility of searching for proteins of a given structure or function. Here we describe a general method for the detection of a protein domain of interest in any species for which a complete proteome exists. In particular, we apply this approach to identify histidine phosphotransfer (HPt) domain-containing proteins across a range of eukaryotic species. From the sequences of known HPt domains, we created an amino acid occurrence matrix which we then used to define a conserved, probabilistic motif. Examination of various organisms either known to contain (plant and fungal species) or believed to lack (mammals) HPt domains established criteria by which new HPt candidates were identified and ranked. Search results using a probabilistic motif matrix compare favorably with data to be found in several commonly used protein structure/function databases: our method identified all known HPt proteins in the Arabidopsis thaliana proteome, confirmed the absence of such motifs in mice and humans, and suggests new candidate HPts in several organisms. Moreover, probabilistic motif searching can be applied more generally, in a manner both readily customized and computationally compact, to other protein domains; this utility is demonstrated by our identification of histones in a range of eukaryotic organisms.
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Affiliation(s)
- Defne Surujon
- Program in Biochemistry and Biophysics, Amherst College, Amherst, Massachusetts, United States of America
| | - David I. Ratner
- Program in Biochemistry and Biophysics, Amherst College, Amherst, Massachusetts, United States of America
- Department of Biology, Amherst College, Amherst, Massachusetts, United States of America
- * E-mail:
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178
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Pekárová B, Szmitkowska A, Dopitová R, Degtjarik O, Žídek L, Hejátko J. Structural Aspects of Multistep Phosphorelay-Mediated Signaling in Plants. MOLECULAR PLANT 2016; 9:71-85. [PMID: 26633861 DOI: 10.1016/j.molp.2015.11.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 11/17/2015] [Accepted: 11/18/2015] [Indexed: 05/16/2023]
Abstract
The multistep phosphorelay (MSP) is a central signaling pathway in plants integrating a wide spectrum of hormonal and environmental inputs and controlling numerous developmental adaptations. For the thorough comprehension of the molecular mechanisms underlying the MSP-mediated signal recognition and transduction, the detailed structural characterization of individual members of the pathway is critical. In this review we describe and discuss the recently known crystal and nuclear magnetic resonance structures of proteins acting in MSP signaling in higher plants, focusing particularly on cytokinin and ethylene signaling in Arabidopsis thaliana. We discuss the range of functional aspects of available structural information including determination of ligand specificity, activation of the receptor via its autophosphorylation, and downstream signal transduction through the phosphorelay. We compare the plant structures with their bacterial counterparts and show that although the overall similarity is high, the differences in structural details are frequent and functionally important. Finally, we discuss emerging knowledge on molecular recognition mechanisms in the MSP, and mention the latest findings regarding structural determinants of signaling specificity in the Arabidopsis MSP that could serve as a general model of this pathway in all higher plants.
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Affiliation(s)
- Blanka Pekárová
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Agnieszka Szmitkowska
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Radka Dopitová
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Oksana Degtjarik
- Faculty of Science, Institute of Chemistry and Biochemistry, University of South Bohemia, 370 05 České Budějovice, Czech Republic
| | - Lukáš Žídek
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Jan Hejátko
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
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179
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Gavrilovic S, Yan Z, Jurkiewicz AM, Stougaard J, Markmann K. Inoculation insensitive promoters for cell type enriched gene expression in legume roots and nodules. PLANT METHODS 2016; 12:4. [PMID: 26807140 PMCID: PMC4724153 DOI: 10.1186/s13007-016-0105-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 01/05/2016] [Indexed: 05/13/2023]
Abstract
BACKGROUND Establishment and maintenance of mutualistic plant-microbial interactions in the rhizosphere and within plant roots involve several root cell types. The processes of host-microbe recognition and infection require complex signal exchange and activation of downstream responses. These molecular events coordinate host responses across root cell layers during microbe invasion, ultimately triggering changes of root cell fates. The progression of legume root interactions with rhizobial bacteria has been addressed in numerous studies. However, tools to globally resolve the succession of molecular events in the host root at the cell type level have been lacking. To this end, we aimed to identify promoters exhibiting cell type enriched expression in roots of the model legume Lotus japonicus, as no comprehensive set of such promoters usable in legume roots is available to date. RESULTS Here, we use promoter:GUS fusions to characterize promoters stemming from Arabidopsis, tomato (Lycopersicon esculentum) or L. japonicus with respect to their expression in major cell types of the L. japonicus root differentiation zone, which shows molecular and morphological responses to symbiotic bacteria and fungi. Out of 24 tested promoters, 11 showed cell type enriched activity in L. japonicus roots. Covered cell types or cell type combinations are epidermis (1), epidermis and cortex (2), cortex (1), endodermis and pericycle (2), pericycle and phloem (4), or xylem (1). Activity of these promoters in the respective cell types was stable during early stages of infection of transgenic roots with the rhizobial symbiont of L. japonicus, Mesorhizobium loti. For a subset of five promoters, expression stability was further demonstrated in whole plant transgenics as well as in active nodules. CONCLUSIONS 11 promoters from Arabidopsis (10) or tomato (1) with enriched activity in major L. japonicus root and nodule cell types have been identified. Root expression patterns are independent of infection with rhizobial bacteria, providing a stable read-out in the root section responsive to symbiotic bacteria. Promoters are available as cloning vectors. We expect these tools to help provide a new dimension to our understanding of signaling circuits and transcript dynamics in symbiotic interactions of legumes with microbial symbionts.
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Affiliation(s)
- Srdjan Gavrilovic
- Department of Molecular Biology and Genetics, Centre for Carbohydrate Recognition and Signalling (CARB), Aarhus University, Gustav Wieds Vej 10, 8000 Aarhus, Denmark
| | - Zhe Yan
- Department of Molecular Biology and Genetics, Centre for Carbohydrate Recognition and Signalling (CARB), Aarhus University, Gustav Wieds Vej 10, 8000 Aarhus, Denmark
| | - Anna M. Jurkiewicz
- Department of Molecular Biology and Genetics, Centre for Carbohydrate Recognition and Signalling (CARB), Aarhus University, Gustav Wieds Vej 10, 8000 Aarhus, Denmark
| | - Jens Stougaard
- Department of Molecular Biology and Genetics, Centre for Carbohydrate Recognition and Signalling (CARB), Aarhus University, Gustav Wieds Vej 10, 8000 Aarhus, Denmark
| | - Katharina Markmann
- Department of Molecular Biology and Genetics, Centre for Carbohydrate Recognition and Signalling (CARB), Aarhus University, Gustav Wieds Vej 10, 8000 Aarhus, Denmark
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180
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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: 45] [Impact Index Per Article: 5.6] [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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181
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Smit ME, Weijers D. The role of auxin signaling in early embryo pattern formation. CURRENT OPINION IN PLANT BIOLOGY 2015; 28:99-105. [PMID: 26495766 DOI: 10.1016/j.pbi.2015.10.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 09/28/2015] [Accepted: 10/02/2015] [Indexed: 05/09/2023]
Abstract
Pattern formation of the early Arabidopsis embryo generates precursors to all major cell types, and is profoundly controlled by the signaling molecule auxin. Here we discuss recent milestones in our understanding of auxin-dependent embryo patterning. Auxin biosynthesis, transport and response mechanisms interact to generate local auxin accumulation in the early embryo. New auxin-dependent reporters help identifying these sites, while atomic structures of transcriptional response mediators help explain the diverse outputs of auxin signaling. Key auxin outputs are control of cell identity and cell division orientation, and progress has been made towards understanding the cellular basis of each. Importantly, a number of studies have combined computational modeling and experiments to analyze the developmental role, genetic circuitry and molecular mechanisms of auxin-dependent cell division control.
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Affiliation(s)
- Margot E Smit
- Laboratory of Biochemistry, Wageningen University, Wageningen, The Netherlands
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, Wageningen, The Netherlands.
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182
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Abstract
Cytokinins comprise a family of signaling molecules essential for regulating the growth and development of plants, acting both locally and at a distance. Although much is known about their biosynthesis and transport, important open questions remain.
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Affiliation(s)
- Asami Osugi
- RIKEN Center for Sustainable Resource Science, 1-7-22, Suehiro, Tsurumi, Yokohama, 230-0045, Japan
| | - Hitoshi Sakakibara
- RIKEN Center for Sustainable Resource Science, 1-7-22, Suehiro, Tsurumi, Yokohama, 230-0045, Japan. .,Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, 464-8601, Japan.
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183
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Katayama H, Iwamoto K, Kariya Y, Asakawa T, Kan T, Fukuda H, Ohashi-Ito K. A Negative Feedback Loop Controlling bHLH Complexes Is Involved in Vascular Cell Division and Differentiation in the Root Apical Meristem. Curr Biol 2015; 25:3144-50. [PMID: 26616019 DOI: 10.1016/j.cub.2015.10.051] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 10/08/2015] [Accepted: 10/26/2015] [Indexed: 12/21/2022]
Abstract
Controlling cell division and differentiation in meristems is essential for proper plant growth. Two bHLH heterodimers consisting of LONESOME HIGHWAY (LHW) and TARGET OF MONOPTEROS 5 (TMO5)/TMO5-LIKE1 (T5L1) regulate periclinal cell division in vascular cells in the root apical meristem (RAM). In this study, we further investigated the functions of LHW-T5L1, finding that in addition to controlling cell division, this complex regulates xylem differentiation in the RAM via a novel negative regulatory system. LHW-T5L1 upregulated the thermospermine synthase gene ACAULIS5 (ACL5), as well as SUPPRESSOR OF ACAULIS5 LIKE3 (SACL3), which encodes a bHLH protein, in the RAM. The SACL3 promoter sequence contains a conserved upstream open reading frame (uORF), which blocked translation of the main SACL3 ORF in the absence of thermospermine. Thermospermine eliminated the negative effect of uORF and enhanced SACL3 production. Further genetic and molecular biological analyses indicated that ACL5 and SACL3 suppress the function of LHW-T5L1 through a protein-protein interaction between LHW and SACL3. Finally, we showed that a negative feedback loop consisting of LHW-T5L1, ACL5, SACL3, and LHW-SACL3 contributes to maintain RAM size and proper root growth. These findings suggest that a negative feedback loop regulates the LHW-T5L1 output level to coordinate cell division and differentiation in a cell-autonomous manner.
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Affiliation(s)
- Hirofumi Katayama
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kuninori Iwamoto
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yuka Kariya
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Tomohiro Asakawa
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Toshiyuki Kan
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Hiroo Fukuda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Kyoko Ohashi-Ito
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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184
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De Rybel B, Mähönen AP, Helariutta Y, Weijers D. Plant vascular development: from early specification to differentiation. Nat Rev Mol Cell Biol 2015; 17:30-40. [PMID: 26580717 DOI: 10.1038/nrm.2015.6] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Vascular tissues in plants are crucial to provide physical support and to transport water, sugars and hormones and other small signalling molecules throughout the plant. Recent genetic and molecular studies have identified interconnections among some of the major signalling networks that regulate plant vascular development. Using Arabidopsis thaliana as a model system, these studies enable the description of vascular development from the earliest tissue specification events during embryogenesis to the differentiation of phloem and xylem tissues. Moreover, we propose a model for how oriented cell divisions give rise to a three-dimensional vascular bundle within the root meristem.
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Affiliation(s)
- Bert De Rybel
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703HA Wageningen, The Netherlands.,Department of Plant Systems Biology, VIB-Ghent University, Technologiepark 927, B-9052 Ghent, Belgium.,Department of Plant Biotechnology and Genetics, Ghent University, Technologiepark 927, B-9052 Ghent, Belgium
| | - Ari Pekka Mähönen
- Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, FIN-00014, Finland
| | - Yrjö Helariutta
- Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, FIN-00014, Finland.,Sainsbury Laboratory, Cambridge University, Bateman Street, Cambridge, CB2 1LR, UK
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703HA Wageningen, The Netherlands
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185
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Vera-Sirera F, De Rybel B, Úrbez C, Kouklas E, Pesquera M, Álvarez-Mahecha J, Minguet E, Tuominen H, Carbonell J, Borst J, Weijers D, Blázquez M. A bHLH-Based Feedback Loop Restricts Vascular Cell Proliferation in Plants. Dev Cell 2015; 35:432-43. [DOI: 10.1016/j.devcel.2015.10.022] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 10/05/2015] [Accepted: 10/23/2015] [Indexed: 01/04/2023]
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186
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el-Showk S, Help-Rinta-Rahko H, Blomster T, Siligato R, Marée AFM, Mähönen AP, Grieneisen VA. Parsimonious Model of Vascular Patterning Links Transverse Hormone Fluxes to Lateral Root Initiation: Auxin Leads the Way, while Cytokinin Levels Out. PLoS Comput Biol 2015; 11:e1004450. [PMID: 26505899 PMCID: PMC4623515 DOI: 10.1371/journal.pcbi.1004450] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 07/17/2015] [Indexed: 12/25/2022] Open
Abstract
An auxin maximum is positioned along the xylem axis of the Arabidopsis root tip. The pattern depends on mutual feedback between auxin and cytokinins mediated by the PIN class of auxin efflux transporters and AHP6, an inhibitor of cytokinin signalling. This interaction has been proposed to regulate the size and the position of the hormones’ respective signalling domains and specify distinct boundaries between them. To understand the dynamics of this regulatory network, we implemented a parsimonious computational model of auxin transport that considers hormonal regulation of the auxin transporters within a spatial context, explicitly taking into account cell shape and polarity and the presence of cell walls. Our analysis reveals that an informative spatial pattern in cytokinin levels generated by diffusion is a theoretically unlikely scenario. Furthermore, our model shows that such a pattern is not required for correct and robust auxin patterning. Instead, auxin-dependent modifications of cytokinin response, rather than variations in cytokinin levels, allow for the necessary feedbacks, which can amplify and stabilise the auxin maximum. Our simulations demonstrate the importance of hormonal regulation of auxin efflux for pattern robustness. While involvement of the PIN proteins in vascular patterning is well established, we predict and experimentally verify a role of AUX1 and LAX1/2 auxin influx transporters in this process. Furthermore, we show that polar localisation of PIN1 generates an auxin flux circuit that not only stabilises the accumulation of auxin within the xylem axis, but also provides a mechanism for auxin to accumulate specifically in the xylem-pole pericycle cells, an important early step in lateral root initiation. The model also revealed that pericycle cells on opposite xylem poles compete for auxin accumulation, consistent with the observation that lateral roots are not initiated opposite to each other. After moving onto land, plants developed vascular tissues to support their weight and transport water and nutrients. Vascular tissue consists of xylem, which makes up wood, and phloem, which gives rise to the innermost bark. In the model species Arabidopsis thaliana, these tissues form in the growing root tip in a radial pattern consisting of a xylem axis and two phloem poles. Xylem is thought to be positioned by negative interactions between two plant hormones, auxin and cytokinins. Cytokinins activate exporters which pump auxin out of cells, while auxin activates a gene which blocks cytokinin response. This leads auxin to accumulate in some cells which become xylem cells. We developed a computational model which includes only the essential processes but allows them to interact in a realistic spatial context. Using this model we show that these interactions can produce the expected auxin pattern even without a pattern in cytokinin distribution, contrary to expectations based on observed patterns in cytokinin signalling. Furthermore, we learned that hormonal regulation fine-tunes the exporters’ activity, and auxin importers play an important role. The regulatory network not only ensures correct formation of the vasculature but may also position root branches on alternating sides of the xylem.
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Affiliation(s)
- Sedeer el-Showk
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- Computational and Systems Biology, John Innes Centre, Norwich United Kingdom
- Department of Biosciences, Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
| | - Hanna Help-Rinta-Rahko
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- Department of Biosciences, Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
| | - Tiina Blomster
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- Department of Biosciences, Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
| | - Riccardo Siligato
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- Department of Biosciences, Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
| | | | - Ari Pekka Mähönen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- Department of Biosciences, Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
- * E-mail: (APM), (VAG)
| | - Verônica A. Grieneisen
- Computational and Systems Biology, John Innes Centre, Norwich United Kingdom
- * E-mail: (APM), (VAG)
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187
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Abstract
Plant growth and development are controlled by nine structurally distinct small molecules termed phytohormones. Over the last 20 years, the molecular basis of their signal transduction, from receptors to transcription factors, has been dissected using mainly Arabidopsis thaliana and rice as model systems. Phytohormones can be broadly classified into two distinct groups on the basis of whether the subcellular localization of their receptors is in the cytoplasm or nucleus, and hence soluble, or membrane-bound, and hence insoluble. Soluble receptors, which control the responses to auxin, jasmonates, gibberellins, strigolactones and salicylic acid, signal either directly or indirectly via the destruction of regulatory proteins. Responses to abscisic acid are primarily mediated by soluble receptors that indirectly regulate the phosphorylation of targeted proteins. Insoluble receptors, which control the responses to cytokinins, brassinosteroids and ethylene, transduce their signal through protein phosphorylation. This chapter provides a comparison of the different components of these signalling systems, and discusses the similarities and differences between them.
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188
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Randall RS, Miyashima S, Blomster T, Zhang J, Elo A, Karlberg A, Immanen J, Nieminen K, Lee JY, Kakimoto T, Blajecka K, Melnyk CW, Alcasabas A, Forzani C, Matsumoto-Kitano M, Mähönen AP, Bhalerao R, Dewitte W, Helariutta Y, Murray JAH. AINTEGUMENTA and the D-type cyclin CYCD3;1 regulate root secondary growth and respond to cytokinins. Biol Open 2015; 4:1229-36. [PMID: 26340943 PMCID: PMC4610221 DOI: 10.1242/bio.013128] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Higher plant vasculature is characterized by two distinct developmental phases. Initially, a well-defined radial primary pattern is established. In eudicots, this is followed by secondary growth, which involves development of the cambium and is required for efficient water and nutrient transport and wood formation. Regulation of secondary growth involves several phytohormones, and cytokinins have been implicated as key players, particularly in the activation of cell proliferation, but the molecular mechanisms mediating this hormonal control remain unknown. Here we show that the genes encoding the transcription factor AINTEGUMENTA (ANT) and the D-type cyclin CYCD3;1 are expressed in the vascular cambium of Arabidopsis roots, respond to cytokinins and are both required for proper root secondary thickening. Cytokinin regulation of ANT and CYCD3 also occurs during secondary thickening of poplar stems, suggesting this represents a conserved regulatory mechanism.
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Affiliation(s)
- Ricardo S Randall
- Department of Molecular Biosciences, Cardiff School of Biosciences, Cardiff University, Cardiff, Wales CF10 3AX, UK
| | - Shunsuke Miyashima
- Department of Biological Sciences, Osaka University, Graduate School of Science, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Tiina Blomster
- Department of Biosciences, Institute of Biotechnology, Viikinkaari 1 (P.O.Box 65), 00014, University of Helsinki, Helsinki, Finland
| | - Jing Zhang
- Department of Biosciences, Institute of Biotechnology, Viikinkaari 1 (P.O.Box 65), 00014, University of Helsinki, Helsinki, Finland
| | - Annakaisa Elo
- Department of Biosciences, Institute of Biotechnology, Viikinkaari 1 (P.O.Box 65), 00014, University of Helsinki, Helsinki, Finland
| | - Anna Karlberg
- Department of Plant Physiology, Umeå University, Umeå SE-901 87, Sweden
| | - Juha Immanen
- Department of Biosciences, Institute of Biotechnology, Viikinkaari 1 (P.O.Box 65), 00014, University of Helsinki, Helsinki, Finland
| | - Kaisa Nieminen
- Department of Biosciences, Institute of Biotechnology, Viikinkaari 1 (P.O.Box 65), 00014, University of Helsinki, Helsinki, Finland
| | - Ji-Young Lee
- School of Biological Sciences, College of Natural Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea
| | - Tatsuo Kakimoto
- Department of Biological Sciences, Osaka University, Graduate School of Science, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Karolina Blajecka
- Sainsbury Laboratory, Cambridge University, Bateman Street, Cambridge CB2 1LR, UK
| | - Charles W Melnyk
- Sainsbury Laboratory, Cambridge University, Bateman Street, Cambridge CB2 1LR, UK
| | - Annette Alcasabas
- Department of Molecular Biosciences, Cardiff School of Biosciences, Cardiff University, Cardiff, Wales CF10 3AX, UK
| | - Celine Forzani
- Department of Molecular Biosciences, Cardiff School of Biosciences, Cardiff University, Cardiff, Wales CF10 3AX, UK
| | - Miho Matsumoto-Kitano
- Department of Biological Sciences, Osaka University, Graduate School of Science, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Ari Pekka Mähönen
- Department of Biosciences, Institute of Biotechnology, Viikinkaari 1 (P.O.Box 65), 00014, University of Helsinki, Helsinki, Finland
| | | | - Walter Dewitte
- Department of Molecular Biosciences, Cardiff School of Biosciences, Cardiff University, Cardiff, Wales CF10 3AX, UK
| | - Ykä Helariutta
- Sainsbury Laboratory, Cambridge University, Bateman Street, Cambridge CB2 1LR, UK
| | - James A H Murray
- Department of Molecular Biosciences, Cardiff School of Biosciences, Cardiff University, Cardiff, Wales CF10 3AX, UK
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189
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Jang G, Lee JH, Rastogi K, Park S, Oh SH, Lee JY. Cytokinin-dependent secondary growth determines root biomass in radish (Raphanus sativus L.). JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4607-19. [PMID: 25979997 PMCID: PMC4507762 DOI: 10.1093/jxb/erv220] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The root serves as an essential organ in plant growth by taking up nutrients and water from the soil and supporting the rest of the plant body. Some plant species utilize roots as storage organs. Sweet potatoes (Ipomoea batatas), cassava (Manihot esculenta), and radish (Raphanus sativus), for example, are important root crops. However, how their root growth is regulated remains unknown. In this study, we characterized the relationship between cambium and radial root growth in radish. Through a comparative analysis with Arabidopsis root expression data, we identified putative cambium-enriched transcription factors in radish and analysed their expression in representative inbred lines featuring distinctive radial growth. We found that cell proliferation activities in the cambium positively correlated with radial growth and final yields of radish roots. Expression analysis of candidate transcription factor genes revealed that some genes are differentially expressed between inbred lines and that the difference is due to the distinct cytokinin response. Taken together, we have demonstrated for the first time, to the best of our knowledge, that cytokinin-dependent radial growth plays a key role in the yields of root crops.
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Affiliation(s)
- Geupil Jang
- School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 151-747, Korea
| | - Jung-Hun Lee
- School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 151-747, Korea
| | - Khushboo Rastogi
- School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 151-747, Korea
| | - Suhyoung Park
- Department of Horticultural Crop Research, National Institute of Horticultural and Herbal Science, Wanju 565-852, Korea
| | - Sang-Hun Oh
- Department of Biology, Daejeon University, Daejeon 300-716, Korea
| | - Ji-Young Lee
- School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 151-747, Korea
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190
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Hrtyan M, Šliková E, Hejátko J, Růžička K. RNA processing in auxin and cytokinin pathways. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4897-912. [PMID: 25922481 DOI: 10.1093/jxb/erv189] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Auxin and cytokinin belong to the 'magnificent seven' plant hormones, having tightly interconnected pathways leading to common as well as opposing effects on plant morphogenesis. Tremendous progress in the past years has yielded a broad understanding of their signalling, metabolism, regulatory pathways, transcriptional networks, and signalling cross-talk. One of the rapidly expanding areas of auxin and cytokinin research concerns their RNA regulatory networks. This review summarizes current knowledge about post-transcriptional gene silencing, the role of non-coding RNAs, the regulation of translation, and alternative splicing of auxin- and cytokinin-related genes. In addition, the role of tRNA-bound cytokinins is also discussed. We highlight the most recent publications dealing with this topic and underline the role of RNA processing in auxin- and cytokinin-mediated growth and development.
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Affiliation(s)
- Mónika Hrtyan
- Department of Functional Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, CZ-62500, Czech Republic
| | - Eva Šliková
- Department of Functional Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, CZ-62500, Czech Republic
| | - Jan Hejátko
- Department of Functional Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, CZ-62500, Czech Republic
| | - Kamil Růžička
- Department of Functional Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, CZ-62500, Czech Republic
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191
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Zdarska M, Dobisová T, Gelová Z, Pernisová M, Dabravolski S, Hejátko J. Illuminating light, cytokinin, and ethylene signalling crosstalk in plant development. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4913-31. [PMID: 26022257 DOI: 10.1093/jxb/erv261] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Integrating important environmental signals with intrinsic developmental programmes is a crucial adaptive requirement for plant growth, survival, and reproduction. Key environmental cues include changes in several light variables, while important intrinsic (and highly interactive) regulators of many developmental processes include the phytohormones cytokinins (CKs) and ethylene. Here, we discuss the latest discoveries regarding the molecular mechanisms mediating CK/ethylene crosstalk at diverse levels of biosynthetic and metabolic pathways and their complex interactions with light. Furthermore, we summarize evidence indicating that multiple hormonal and light signals are integrated in the multistep phosphorelay (MSP) pathway, a backbone signalling pathway in plants. Inter alia, there are strong overlaps in subcellular localizations and functional similarities in components of these pathways, including receptors and various downstream agents. We highlight recent research demonstrating the importance of CK/ethylene/light crosstalk in selected aspects of plant development, particularly seed germination and early seedling development. The findings clearly demonstrate the crucial integration of plant responses to phytohormones and adaptive responses to environmental cues. Finally, we tentatively identify key future challenges to refine our understanding of the molecular mechanisms mediating crosstalk between light and hormonal signals, and their integration during plant life cycles.
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Affiliation(s)
- Marketa Zdarska
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno 62500, Czech Republic
| | - Tereza Dobisová
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno 62500, Czech Republic
| | - Zuzana Gelová
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno 62500, Czech Republic
| | - Markéta Pernisová
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno 62500, Czech Republic
| | - Siarhei Dabravolski
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno 62500, Czech Republic
| | - Jan Hejátko
- Functional Genomics and Proteomics of Plants, Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, Brno 62500, Czech Republic
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192
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Růžička K, Ursache R, Hejátko J, Helariutta Y. Xylem development - from the cradle to the grave. THE NEW PHYTOLOGIST 2015; 207:519-35. [PMID: 25809158 DOI: 10.1111/nph.13383] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 02/21/2015] [Indexed: 05/06/2023]
Abstract
The development and growth of plants, as well as their successful adaptation to a variety of environments, is highly dependent on the conduction of water, nutrients and other important molecules throughout the plant body. Xylem is a specialized vascular tissue that serves as a conduit of water and minerals and provides mechanical support for upright growth. Wood, also known as secondary xylem, constitutes the major part of mature woody stems and roots. In the past two decades, a number of key factors including hormones, signal transducers and (post)transcriptional regulators have been shown to control xylem formation. We outline the main mechanisms shown to be essential for xylem development in various plant species, with an emphasis on Arabidopsis thaliana, as well as several tree species where xylem has a long history of investigation. We also summarize the processes which have been shown to be instrumental during xylem maturation. This includes mechanisms of cell wall formation and cell death which collectively complete xylem cell fate.
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Affiliation(s)
- Kamil Růžička
- Department of Functional Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 25, Brno, CZ-62500, Czech Republic
| | - Robertas Ursache
- Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, CB2 1LR, UK
| | - Jan Hejátko
- Department of Functional Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 25, Brno, CZ-62500, Czech Republic
| | - Ykä Helariutta
- Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, CB2 1LR, UK
- Institute of Biotechnology, University of Helsinki, PO Box 65, Helsinki, FIN-00014, Finland
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193
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Wang GL, Sun S, Xing GM, Wu XJ, Wang F, Xiong AS. Morphological Characteristics, Anatomical Structure, and Gene Expression: Novel Insights into Cytokinin Accumulation during Carrot Growth and Development. PLoS One 2015. [PMID: 26218147 PMCID: PMC4517795 DOI: 10.1371/journal.pone.0134166] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Cytokinins have been implicated in normal plant growth and development. These bioactive molecules are essential for cell production and expansion in higher plants. Carrot is an Apiaceae vegetable with great value and undergoes significant size changes over the process of plant growth. However, cytokinin accumulation and its potential roles in carrot growth have not been elucidated. To address this problem, carrot plants at five stages were collected, and morphological and anatomical characteristics and expression profiles of cytokinin-related genes were determined. During carrot growth and development, cytokinin levels were the highest at the second stage in the roots, whereas relatively stable levels were observed in the petioles and leaves. DcCYP735A2 showed high expression at stage 2 in the roots, which may contribute largely to the higher cytokinin level at this stage. However, expression of most metabolic genes did not follow a pattern similar to that of cytokinin accumulation, indicating that cytokinin biosynthesis was regulated through a complex network. Genes involved in cytokinin signal perception and transduction were also integrated to normal plant growth and development. The results from the present work suggested that cytokinins may regulate plant growth in a stage-dependent manner. Our work would shed novel insights into cytokinin accumulation and its potential roles during carrot growth. Further studies regarding carrot cytokinins may be achieved by modification of the genes involved in cytokinin biosynthesis, inactivation, and perception.
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Affiliation(s)
- Guang-Long Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Sheng Sun
- College of Horticulture, Shanxi Agricultural University, Taigu, 030801, China
| | - Guo-Ming Xing
- College of Horticulture, Shanxi Agricultural University, Taigu, 030801, China
| | - Xue-Jun Wu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Feng Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ai-Sheng Xiong
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
- * E-mail:
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194
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Ghuge SA, Tisi A, Carucci A, Rodrigues-Pousada RA, Franchi S, Tavladoraki P, Angelini R, Cona A. Cell Wall Amine Oxidases: New Players in Root Xylem Differentiation under Stress Conditions. PLANTS 2015; 4:489-504. [PMID: 27135338 PMCID: PMC4844406 DOI: 10.3390/plants4030489] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 06/12/2015] [Accepted: 07/09/2015] [Indexed: 12/11/2022]
Abstract
Polyamines (PAs) are aliphatic polycations present in all living organisms. A growing body of evidence reveals their involvement as regulators in a variety of physiological and pathological events. They are oxidatively deaminated by amine oxidases (AOs), including copper amine oxidases (CuAOs) and flavin adenine dinucleotide (FAD)-dependent polyamine oxidases (PAOs). The biologically-active hydrogen peroxide (H2O2) is a shared compound in all of the AO-catalyzed reactions, and it has been reported to play important roles in PA-mediated developmental and stress-induced processes. In particular, the AO-driven H2O2 biosynthesis in the cell wall is well known to be involved in plant wound healing and pathogen attack responses by both triggering peroxidase-mediated wall-stiffening events and signaling modulation of defense gene expression. Extensive investigation by a variety of methodological approaches revealed high levels of expression of cell wall-localized AOs in root xylem tissues and vascular parenchyma of different plant species. Here, the recent progresses in understanding the role of cell wall-localized AOs as mediators of root xylem differentiation during development and/or under stress conditions are reviewed. A number of experimental pieces of evidence supports the involvement of apoplastic H2O2 derived from PA oxidation in xylem tissue maturation under stress-simulated conditions.
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Affiliation(s)
- Sandip A Ghuge
- Institute of Crystallography, Consiglio Nazionale delle Ricerche (CNR), Monterotondo 00015, Italy.
| | - Alessandra Tisi
- Department of Sciences, Università Roma Tre, Roma 00146, Italy.
| | - Andrea Carucci
- Department of Sciences, Università Roma Tre, Roma 00146, Italy.
| | | | - Stefano Franchi
- Department of Sciences, Università Roma Tre, Roma 00146, Italy.
| | - Paraskevi Tavladoraki
- Department of Sciences, Università Roma Tre, Roma 00146, Italy.
- Istituto Nazionale Biostrutture e Biosistemi (INBB), Rome 00136, Italy.
| | - Riccardo Angelini
- Department of Sciences, Università Roma Tre, Roma 00146, Italy.
- Istituto Nazionale Biostrutture e Biosistemi (INBB), Rome 00136, Italy.
| | - Alessandra Cona
- Department of Sciences, Università Roma Tre, Roma 00146, Italy.
- Istituto Nazionale Biostrutture e Biosistemi (INBB), Rome 00136, Italy.
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195
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Nieminen K, Blomster T, Helariutta Y, Mähönen AP. Vascular Cambium Development. THE ARABIDOPSIS BOOK 2015; 13:e0177. [PMID: 26078728 PMCID: PMC4463761 DOI: 10.1199/tab.0177] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Secondary phloem and xylem tissues are produced through the activity of vascular cambium, the cylindrical secondary meristem which arises among the primary plant tissues. Most dicotyledonous species undergo secondary development, among them Arabidopsis. Despite its small size and herbaceous nature, Arabidopsis displays prominent secondary growth in several organs, including the root, hypocotyl and shoot. Together with the vast genetic resources and molecular research methods available for it, this has made Arabidopsis a versatile and accessible model organism for studying cambial development and wood formation. In this review, we discuss and compare the development and function of the vascular cambium in the Arabidopsis root, hypocotyl, and shoot. We describe the current understanding of the molecular regulation of vascular cambium and compare it to the function of primary meristems. We conclude with a look at the future prospects of cambium research, including opportunities provided by phenotyping and modelling approaches, complemented by studies of natural variation and comparative genetic studies in perennial and woody plant species.
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Affiliation(s)
- Kaisa Nieminen
- Natural Resources Institute Finland (Luke), Green Technology, Vantaa 01301, Finland
| | - Tiina Blomster
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
- Department of Biosciences, University of Helsinki, Helsinki 00014, Finland
| | - Ykä Helariutta
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
- Department of Biosciences, University of Helsinki, Helsinki 00014, Finland
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK
- Cardiff University Cardiff School of Biosciences, The Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Ari Pekka Mähönen
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
- Department of Biosciences, University of Helsinki, Helsinki 00014, Finland
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196
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Chandler JW, Werr W. Cytokinin-auxin crosstalk in cell type specification. TRENDS IN PLANT SCIENCE 2015; 20:291-300. [PMID: 25805047 DOI: 10.1016/j.tplants.2015.02.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/13/2015] [Accepted: 02/24/2015] [Indexed: 05/24/2023]
Abstract
Auxin and cytokinin affect cell fate specification transcriptionally and non-transcriptionally, and their roles have been characterised in several founder cell specification and activation contexts. Similarly to auxin, local cytokinin synthesis and response gradients are instructive, and the roles of ARABIDOPSIS RESPONSE REGULATOR 7/15 (ARR7/15) and the negative cytokinin response regulator ARABIDOPSIS HISTIDINE PHOSPHOTRANSFER PROTEIN 6, as well as auxin signalling via MONOPTEROS/BODENLOS, are functionally conserved across different developmental processes. Auxin and cytokinin crosstalk is tissue- and context-specific, and may be synergistic in the shoot apical meristem (SAM) but antagonistic in the root. We review recent advances in understanding the interactions between auxin and cytokinin in pivotal developmental processes, and show that feedback complexity and the multistep nature of specification processes argue against a single morphogenetic signal.
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Affiliation(s)
- John William Chandler
- Institute of Developmental Biology, Cologne Biocenter, Zülpicher Strasse 47b, 50674 Cologne, Germany.
| | - Wolfgang Werr
- Institute of Developmental Biology, Cologne Biocenter, Zülpicher Strasse 47b, 50674 Cologne, Germany
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197
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Sebastian J, Ryu KH, Zhou J, Tarkowská D, Tarkowski P, Cho YH, Yoo SD, Kim ES, Lee JY. PHABULOSA controls the quiescent center-independent root meristem activities in Arabidopsis thaliana. PLoS Genet 2015; 11:e1004973. [PMID: 25730098 PMCID: PMC4346583 DOI: 10.1371/journal.pgen.1004973] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 12/23/2014] [Indexed: 11/23/2022] Open
Abstract
Plant growth depends on stem cell niches in meristems. In the root apical meristem, the quiescent center (QC) cells form a niche together with the surrounding stem cells. Stem cells produce daughter cells that are displaced into a transit-amplifying (TA) domain of the root meristem. TA cells divide several times to provide cells for growth. SHORTROOT (SHR) and SCARECROW (SCR) are key regulators of the stem cell niche. Cytokinin controls TA cell activities in a dose-dependent manner. Although the regulatory programs in each compartment of the root meristem have been identified, it is still unclear how they coordinate one another. Here, we investigate how PHABULOSA (PHB), under the posttranscriptional control of SHR and SCR, regulates TA cell activities. The root meristem and growth defects in shr or scr mutants were significantly recovered in the shr phb or scr phb double mutant, respectively. This rescue in root growth occurs in the absence of a QC. Conversely, when the modified PHB, which is highly resistant to microRNA, was expressed throughout the stele of the wild-type root meristem, root growth became very similar to that observed in the shr; however, the identity of the QC was unaffected. Interestingly, a moderate increase in PHB resulted in a root meristem phenotype similar to that observed following the application of high levels of cytokinin. Our protoplast assay and transgenic approach using ARR10 suggest that the depletion of TA cells by high PHB in the stele occurs via the repression of B-ARR activities. This regulatory mechanism seems to help to maintain the cytokinin homeostasis in the meristem. Taken together, our study suggests that PHB can dynamically regulate TA cell activities in a QC-independent manner, and that the SHR-PHB pathway enables a robust root growth system by coordinating the stem cell niche and TA domain. Plant roots are programmed to grow continuously into the soil, searching for nutrients and water. The iterative process of cell division, elongation, and differentiation contributes to root growth. The quiescent center (QC) is known to maintain the root meristem, and thus ensure root growth. In this study, we report a novel aspect of root growth regulation controlled independently of the QC by PHABULOSA (PHB). In shr mutant plants, PHB, which in the meristem is actively restricted to the central region of the stele by SHORTROOT (SHR) via miR165/6, suppresses root meristem activity leading to root growth arrest. A high concentration of PHB in the stele does this by modulating B-ARR activity through a QC-independent pathway. Accordingly, we observed a significant recovery of root meristem activity and growth in the shr phb double mutant, while the QC remained absent. However, the presence of QC may be required to sustain continuous root growth. On the basis of our results, we propose that SHR maintains root growth via two separate pathways: by modulating PHB levels in the root stele, and by maintaining the QC identity.
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Affiliation(s)
- Jose Sebastian
- Boyce Thompson Institute for Plant Research, Ithaca, New York, United States of America
| | - Kook Hui Ryu
- School of Biological Sciences, Seoul National University, Seoul, Korea
| | - Jing Zhou
- Boyce Thompson Institute for Plant Research, Ithaca, New York, United States of America
| | - Danuše Tarkowská
- Laboratory of Growth Regulators, Faculty of Science, Palacky University and Institute of Experimental Botany AS CR, Olomouc, Czech Republic
| | - Petr Tarkowski
- Department of Protein Biochemistry and Proteomics, Centre of the Region Hana for Biotechnological and Agricultural Research, Faculty of Science, Palacky University, Olomouc, Czech Republic,
| | - Young-Hee Cho
- School of Life Sciences and Biotechnology, Korea University, Seoul, Korea
| | - Sang-Dong Yoo
- School of Life Sciences and Biotechnology, Korea University, Seoul, Korea
| | - Eun-Sol Kim
- School of Biological Sciences, Seoul National University, Seoul, Korea
| | - Ji-Young Lee
- Boyce Thompson Institute for Plant Research, Ithaca, New York, United States of America
- School of Biological Sciences, Seoul National University, Seoul, Korea
- * E-mail:
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198
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Jouannet V, Brackmann K, Greb T. (Pro)cambium formation and proliferation: two sides of the same coin? CURRENT OPINION IN PLANT BIOLOGY 2015; 23:54-60. [PMID: 25449727 PMCID: PMC4353845 DOI: 10.1016/j.pbi.2014.10.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 10/16/2014] [Accepted: 10/16/2014] [Indexed: 05/17/2023]
Abstract
The body of higher plants is usually pervaded by the (pro)cambium, a reticulate system of meristematic cells harboring the potential for producing vascular tissues at critical times and places. The (pro)cambium thereby provides the basis for the differential modulation of long-distance transport capacities and plant body stability. Distinct regulatory networks responsible for the initiation and proliferation of (pro)cambium cells have been identified. However, although a tight interaction between these networks can be expected, connections have been established only sporadically. Here we highlight recent discoveries of how (pro)cambium development is regulated and discuss possible interfaces between networks regulating two processes: (pro)cambium formation and cambium proliferation.
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Affiliation(s)
- Virginie Jouannet
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Klaus Brackmann
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Thomas Greb
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.
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199
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ten Hove CA, Lu KJ, Weijers D. Building a plant: cell fate specification in the early Arabidopsis embryo. Development 2015; 142:420-30. [DOI: 10.1242/dev.111500] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Embryogenesis is the beginning of plant development, yet the cell fate decisions and patterning steps that occur during this time are reiterated during development to build the post-embryonic architecture. In Arabidopsis, embryogenesis follows a simple and predictable pattern, making it an ideal model with which to understand how cellular and tissue developmental processes are controlled. Here, we review the early stages of Arabidopsis embryogenesis, focusing on the globular stage, during which time stem cells are first specified and all major tissues obtain their identities. We discuss four different aspects of development: the formation of outer versus inner layers; the specification of vascular and ground tissues; the determination of shoot and root domains; and the establishment of the first stem cells.
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Affiliation(s)
- Colette A. ten Hove
- Wageningen University, Laboratory of Biochemistry, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
| | - Kuan-Ju Lu
- Wageningen University, Laboratory of Biochemistry, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
| | - Dolf Weijers
- Wageningen University, Laboratory of Biochemistry, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
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200
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Zhao J, Bai W, Zeng Q, Song S, Zhang M, Li X, Hou L, Xiao Y, Luo M, Li D, Luo X, Pei Y. Moderately enhancing cytokinin level by down-regulation of GhCKX expression in cotton concurrently increases fiber and seed yield. MOLECULAR BREEDING : NEW STRATEGIES IN PLANT IMPROVEMENT 2015; 35:60. [PMID: 25653571 PMCID: PMC4309883 DOI: 10.1007/s11032-015-0232-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 08/29/2014] [Indexed: 05/03/2023]
Abstract
Cotton is the leading natural fiber crop in the world. Cotton seeds are also an important oil and protein source. However, enhancement of fiber abundance usually leads to a smaller seed. Thus, it has become a challenge for cotton breeding to concurrently increase fiber yield and seed yield. To improve cotton yield, we elevated the endogenous cytokinin level in transgenic cotton by constitutive suppression of cytokinin dehydrogenase (CKX), a key negative regulator controlling endogenous cytokinin in plants. The slightly and moderately suppressed transgenic cotton plants showed normal growth and development, while the severely suppressed plants exhibited a typical cytokinin-overproduction alteration. The suppression of CKX led to an enhancement of endogenous cytokinins in transgenic cotton plants. Total cytokinins in moderately suppressed lines, CR-3 and CR-6, increased by 20.4 and 55.5 % respectively, and that in the severely suppressed line (CR-13) increased by 134.2 % compared to the wild type. The moderately suppressed lines showed a delay in leaf senescence, higher photosynthesis, more fruiting branches and bolls, and bigger seed size. Field trials showed that seed yield and lint yield of the moderately suppressed CR-6 line increased by 15.4 and 20.0 %, respectively. Meanwhile, the enhanced cytokinin level in transgenic cottons did not show significant influence on fiber qualities. Our data demonstrated that CKX is a promising gene for crop yield improvement.
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Affiliation(s)
- Juan Zhao
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Wenqin Bai
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Qiwei Zeng
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Shuiqing Song
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Mi Zhang
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Xianbi Li
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Lei Hou
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Yuehua Xiao
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Ming Luo
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Demou Li
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Xiaoying Luo
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
| | - Yan Pei
- Biotechnology Research Center, Southwest University, No. 2 Tiansheng Road, Beibei, Chongqing, 400716 People’s Republic of China
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