301
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Osuna D, Prieto P, Aguilar M. Control of Seed Germination and Plant Development by Carbon and Nitrogen Availability. FRONTIERS IN PLANT SCIENCE 2015; 6:1023. [PMID: 26635847 PMCID: PMC4649081 DOI: 10.3389/fpls.2015.01023] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 11/05/2015] [Indexed: 05/20/2023]
Abstract
Little is known about the molecular basis of the influence of external carbon/nitrogen (C/N) ratio and other abiotic factors on phytohormones regulation during seed germination and plant developmental processes, and the identification of elements that participate in this response is essential to understand plant nutrient perception and signaling. Sugars (sucrose, glucose) and nitrate not only act as nutrients but also as signaling molecules in plant development. A connection between changes in auxin transport and nitrate signal transduction has been reported in Arabidopsis thaliana through the NRT1.1, a nitrate sensor and transporter that also functions as a repressor of lateral root growth under low concentrations of nitrate by promoting auxin transport. Nitrate inhibits the elongation of lateral roots, but this effect is significantly reduced in abscisic acid (ABA)-insensitive mutants, what suggests that ABA might mediate the inhibition of lateral root elongation by nitrate. Gibberellin (GA) biosynthesis has been also related to nitrate level in seed germination and its requirement is determined by embryonic ABA. These mechanisms connect nutrients and hormones signaling during seed germination and plant development. Thus, the genetic identification of the molecular components involved in nutrients-dependent pathways would help to elucidate the potential crosstalk between nutrients, nitric oxide (NO) and phytohormones (ABA, auxins and GAs) in seed germination and plant development. In this review we focus on changes in C and N levels and how they control seed germination and plant developmental processes through the interaction with other plant growth regulators, such as phytohormones.
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Affiliation(s)
- Daniel Osuna
- Institute for Sustainable Agriculture, Agencia Estatal Consejo Superior de Investigaciones Científicas, Córdoba, Spain,
- *Correspondence: Daniel Osuna,
| | - Pilar Prieto
- Institute for Sustainable Agriculture, Agencia Estatal Consejo Superior de Investigaciones Científicas, Córdoba, Spain,
| | - Miguel Aguilar
- Área de Fisiología Vegetal, Facultad de Ciencias, Universidad de Córdoba, Córdoba, Spain
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302
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Roy R, Bassham DC. Gravitropism and Lateral Root Emergence are Dependent on the Trans-Golgi Network Protein TNO1. FRONTIERS IN PLANT SCIENCE 2015; 6:969. [PMID: 26617617 PMCID: PMC4642138 DOI: 10.3389/fpls.2015.00969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 10/22/2015] [Indexed: 05/07/2023]
Abstract
The trans-Golgi network (TGN) is a dynamic organelle that functions as a relay station for receiving endocytosed cargo, directing secretory cargo, and trafficking to the vacuole. TGN-localized SYP41-interacting protein (TNO1) is a large, TGN-localized, coiled-coil protein that associates with the membrane fusion protein SYP41, a target SNARE, and is required for efficient protein trafficking to the vacuole. Here, we show that a tno1 mutant has auxin transport-related defects. Mutant roots have delayed lateral root emergence, decreased gravitropic bending of plant organs and increased sensitivity to the auxin analog 2,4-dichlorophenoxyacetic acid and the natural auxin 3-indoleacetic acid. Auxin asymmetry at the tips of elongating stage II lateral roots was reduced in the tno1 mutant, suggesting a role for TNO1 in cellular auxin transport during lateral root emergence. During gravistimulation, tno1 roots exhibited delayed auxin transport from the columella to the basal epidermal cells. Endocytosis to the TGN was unaffected in the mutant, indicating that bulk endocytic defects are not responsible for the observed phenotypes. Together these studies demonstrate a role for TNO1 in mediating auxin responses during root development and gravistimulation, potentially through trafficking of auxin transport proteins.
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Affiliation(s)
- Rahul Roy
- Department of Genetics, Development and Cell Biology, Iowa State University, AmesIA, USA
- Interdepartmental Genetics Program, Iowa State University, AmesIA, USA
| | - Diane C. Bassham
- Department of Genetics, Development and Cell Biology, Iowa State University, AmesIA, USA
- Interdepartmental Genetics Program, Iowa State University, AmesIA, USA
- Plant Sciences Institute, Iowa State University, AmesIA, USA
- *Correspondence: Diane C. Bassham,
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303
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Bimodal regulation of ICR1 levels generates self-organizing auxin distribution. Proc Natl Acad Sci U S A 2014; 111:E5471-9. [PMID: 25468974 DOI: 10.1073/pnas.1413918111] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Auxin polar transport, local maxima, and gradients have become an important model system for studying self-organization. Auxin distribution is regulated by auxin-dependent positive feedback loops that are not well-understood at the molecular level. Previously, we showed the involvement of the RHO of Plants (ROP) effector INTERACTOR of CONSTITUTIVELY active ROP 1 (ICR1) in regulation of auxin transport and that ICR1 levels are posttranscriptionally repressed at the site of maximum auxin accumulation at the root tip. Here, we show that bimodal regulation of ICR1 levels by auxin is essential for regulating formation of auxin local maxima and gradients. ICR1 levels increase concomitant with increase in auxin response in lateral root primordia, cotyledon tips, and provascular tissues. However, in the embryo hypophysis and root meristem, when auxin exceeds critical levels, ICR1 is rapidly destabilized by an SCF(TIR1/AFB) [SKP, Cullin, F-box (transport inhibitor response 1/auxin signaling F-box protein)]-dependent auxin signaling mechanism. Furthermore, ectopic expression of ICR1 in the embryo hypophysis resulted in reduction of auxin accumulation and concomitant root growth arrest. ICR1 disappeared during root regeneration and lateral root initiation concomitantly with the formation of a local auxin maximum in response to external auxin treatments and transiently after gravitropic stimulation. Destabilization of ICR1 was impaired after inhibition of auxin transport and signaling, proteasome function, and protein synthesis. A mathematical model based on these findings shows that an in vivo-like auxin distribution, rootward auxin flux, and shootward reflux can be simulated without assuming preexisting tissue polarity. Our experimental results and mathematical modeling indicate that regulation of auxin distribution is tightly associated with auxin-dependent ICR1 levels.
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304
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Rutschow HL, Baskin TI, Kramer EM. The carrier AUXIN RESISTANT (AUX1) dominates auxin flux into Arabidopsis protoplasts. THE NEW PHYTOLOGIST 2014; 204:536-544. [PMID: 25039492 DOI: 10.1111/nph.12933] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 06/15/2014] [Indexed: 05/22/2023]
Abstract
The ability of the plant hormone auxin to enter a cell is critical to auxin transport and signaling. Auxin can cross the cell membrane by diffusion or via auxin-specific influx carriers. There is little knowledge of the magnitudes of these fluxes in plants. Radiolabeled auxin uptake was measured in protoplasts isolated from roots of Arabidopsis thaliana. This was done for the wild-type, under treatments with additional unlabeled auxin to saturate the influx carriers, and for the influx carrier mutant auxin resistant 1 (aux1). We also used flow cytometry to quantify the relative abundance of cells expressing AUX1-YFP in the assayed population. At pH 5.7, the majority of auxin influx into protoplasts - 75% - was mediated by the influx carrier AUX1. An additional 20% was mediated by other saturable carriers. The diffusive influx of auxin was essentially negligible at pH 5.7. The influx of auxin mediated by AUX1, expressed as a membrane permeability, was 1.5 ± 0.3 μm s(-1) . This value is comparable in magnitude to estimates of efflux permeability. Thus, auxin-transporting tissues can sustain relatively high auxin efflux and yet not become depleted of auxin.
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Affiliation(s)
- Heidi L Rutschow
- Biology Department, University of Massachusetts, Amherst, MA, 01003, USA
- Physics Department, Bard College at Simons Rock, Great Barrington, MA, 01230, USA
| | - Tobias I Baskin
- Biology Department, University of Massachusetts, Amherst, MA, 01003, USA
| | - Eric M Kramer
- Physics Department, Bard College at Simons Rock, Great Barrington, MA, 01230, USA
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305
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Maeda S, Gunji S, Hanai K, Hirano T, Kazama Y, Ohbayashi I, Abe T, Sawa S, Tsukaya H, Ferjani A. The conflict between cell proliferation and expansion primarily affects stem organogenesis in Arabidopsis. PLANT & CELL PHYSIOLOGY 2014; 55:1994-2007. [PMID: 25246492 DOI: 10.1093/pcp/pcu131] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Plant shoot organs such as stems, leaves and flowers are derived from specialized groups of stem cells organized at the shoot apical meristem (SAM). Organogenesis involves two major processes, namely cell proliferation and differentiation, whereby the former contributes to increasing the cell number and the latter involves substantial increases in cell volume through cell expansion. Co-ordination between the above processes in time and space is essential for proper organogenesis. To identify regulatory factors involved in proper organogenesis, heavy-ion beam-irradiated de-etiolated (det) 3-1 seeds have been used to identify striking phenotypes in the A#26-2; det3-1 mutant. In addition to the stunted plant stature mimicking det3-1, the A#26-2; det3-1 mutant exhibited stem thickening, increased floral organ number and a fruit shape reminiscent of clavata (clv) mutants. DNA sequencing analysis demonstrated that A#26-2; det3-1 harbors a mutation in the CLV3 gene. Importantly, A#26-2; det3-1 displayed cracks that randomly occurred on the main stem with a frequency of approximately 50%. Furthermore, the double mutants clv3-8 det3-1, clv1-4 det3-1 and clv2-1 det3-1 consistently showed stem cracks with frequencies of approximately 97, 38 and 35%, respectively. Cross-sections of stems further revealed an increase in vascular bundle number, cell number and size in the pith of clv3-8 det3-1 compared with det3-1. These findings suggest that the stem inner volume increase due to clv mutations exerts an outward mechanical stress; that in a det3-1 background (defective in cell expansion) resulted in cracking of the outermost layer of epidermal cells.
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Affiliation(s)
- Saori Maeda
- Department of Biology, Tokyo Gakugei University, Koganei-shi, 184-8501 Japan These authors contributed equally to this work
| | - Shizuka Gunji
- Department of Biology, Tokyo Gakugei University, Koganei-shi, 184-8501 Japan These authors contributed equally to this work
| | - Kenya Hanai
- Department of Biology, Tokyo Gakugei University, Koganei-shi, 184-8501 Japan These authors contributed equally to this work
| | - Tomonari Hirano
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama, 351-0198 Japan
| | - Yusuke Kazama
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama, 351-0198 Japan
| | - Iwai Ohbayashi
- Department of Biology, Tokyo Gakugei University, Koganei-shi, 184-8501 Japan
| | - Tomoko Abe
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama, 351-0198 Japan
| | - Shinichiro Sawa
- Graduate School of Science and Technology, Kumamoto University, Chuo-ku, 860-8555 Japan
| | - Hirokazu Tsukaya
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, 113-0033 Japan
| | - Ali Ferjani
- Department of Biology, Tokyo Gakugei University, Koganei-shi, 184-8501 Japan
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306
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Atkinson JA, Rasmussen A, Traini R, Voß U, Sturrock C, Mooney SJ, Wells DM, Bennett MJ. Branching out in roots: uncovering form, function, and regulation. PLANT PHYSIOLOGY 2014; 166:538-50. [PMID: 25136060 PMCID: PMC4213086 DOI: 10.1104/pp.114.245423] [Citation(s) in RCA: 153] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 08/12/2013] [Indexed: 05/18/2023]
Abstract
Root branching is critical for plants to secure anchorage and ensure the supply of water, minerals, and nutrients. To date, research on root branching has focused on lateral root development in young seedlings. However, many other programs of postembryonic root organogenesis exist in angiosperms. In cereal crops, the majority of the mature root system is composed of several classes of adventitious roots that include crown roots and brace roots. In this Update, we initially describe the diversity of postembryonic root forms. Next, we review recent advances in our understanding of the genes, signals, and mechanisms regulating lateral root and adventitious root branching in the plant models Arabidopsis (Arabidopsis thaliana), maize (Zea mays), and rice (Oryza sativa). While many common signals, regulatory components, and mechanisms have been identified that control the initiation, morphogenesis, and emergence of new lateral and adventitious root organs, much more remains to be done. We conclude by discussing the challenges and opportunities facing root branching research.
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Affiliation(s)
- Jonathan A Atkinson
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
| | - Amanda Rasmussen
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
| | - Richard Traini
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
| | - Ute Voß
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
| | - Craig Sturrock
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
| | - Sacha J Mooney
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
| | - Darren M Wells
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
| | - Malcolm J Bennett
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, United Kingdom (J.A.A., A.R., R.T., U.V., C.S., S.J.M., D.M.W., M.J.B.); andCollege of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia (M.J.B.)
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307
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Sénéchal F, Wattier C, Rustérucci C, Pelloux J. Homogalacturonan-modifying enzymes: structure, expression, and roles in plants. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:5125-60. [PMID: 25056773 PMCID: PMC4400535 DOI: 10.1093/jxb/eru272] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 05/20/2014] [Accepted: 05/22/2014] [Indexed: 05/18/2023]
Abstract
Understanding the changes affecting the plant cell wall is a key element in addressing its functional role in plant growth and in the response to stress. Pectins, which are the main constituents of the primary cell wall in dicot species, play a central role in the control of cellular adhesion and thereby of the rheological properties of the wall. This is likely to be a major determinant of plant growth. How the discrete changes in pectin structure are mediated is thus a key issue in our understanding of plant development and plant responses to changes in the environment. In particular, understanding the remodelling of homogalacturonan (HG), the most abundant pectic polymer, by specific enzymes is a current challenge in addressing its fundamental role. HG, a polymer that can be methylesterified or acetylated, can be modified by HGMEs (HG-modifying enzymes) which all belong to large multigenic families in all species sequenced to date. In particular, both the degrees of substitution (methylesterification and/or acetylation) and polymerization can be controlled by specific enzymes such as pectin methylesterases (PMEs), pectin acetylesterases (PAEs), polygalacturonases (PGs), or pectate lyases-like (PLLs). Major advances in the biochemical and functional characterization of these enzymes have been made over the last 10 years. This review aims to provide a comprehensive, up to date summary of the recent data concerning the structure, regulation, and function of these fascinating enzymes in plant development and in response to biotic stresses.
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Affiliation(s)
- Fabien Sénéchal
- EA3900 BIOPI Biologie des Plantes et Innovation, Université de Picardie Jules Verne, 33 Rue St Leu, F-80039 Amiens, France
| | - Christopher Wattier
- EA3900 BIOPI Biologie des Plantes et Innovation, Université de Picardie Jules Verne, 33 Rue St Leu, F-80039 Amiens, France
| | - Christine Rustérucci
- EA3900 BIOPI Biologie des Plantes et Innovation, Université de Picardie Jules Verne, 33 Rue St Leu, F-80039 Amiens, France
| | - Jérôme Pelloux
- EA3900 BIOPI Biologie des Plantes et Innovation, Université de Picardie Jules Verne, 33 Rue St Leu, F-80039 Amiens, France
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308
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Verstraeten I, Schotte S, Geelen D. Hypocotyl adventitious root organogenesis differs from lateral root development. FRONTIERS IN PLANT SCIENCE 2014; 5:495. [PMID: 25324849 PMCID: PMC4179338 DOI: 10.3389/fpls.2014.00495] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Accepted: 09/06/2014] [Indexed: 05/02/2023]
Abstract
Wound-induced adventitious root (AR) formation is a requirement for plant survival upon root damage inflicted by pathogen attack, but also during the regeneration of plant stem cuttings for clonal propagation of elite plant varieties. Yet, adventitious rooting also takes place without wounding. This happens for example in etiolated Arabidopsis thaliana hypocotyls, in which AR initiate upon de-etiolation or in tomato seedlings, in which AR initiate upon flooding or high water availability. In the hypocotyl AR originate from a cell layer reminiscent to the pericycle in the primary root (PR) and the initiated AR share histological and developmental characteristics with lateral roots (LRs). In contrast to the PR however, the hypocotyl is a determinate structure with an established final number of cells. This points to differences between the induction of hypocotyl AR and LR on the PR, as the latter grows indeterminately. The induction of AR on the hypocotyl takes place in environmental conditions that differ from those that control LR formation. Hence, AR formation depends on differentially regulated gene products. Similarly to AR induction in stem cuttings, the capacity to induce hypocotyl AR is genotype-dependent and the plant growth regulator auxin is a key regulator controlling the rooting response. The hormones cytokinins, ethylene, jasmonic acid, and strigolactones in general reduce the root-inducing capacity. The involvement of this many regulators indicates that a tight control and fine-tuning of the initiation and emergence of AR exists. Recently, several genetic factors, specific to hypocotyl adventitious rooting in A. thaliana, have been uncovered. These factors reveal a dedicated signaling network that drives AR formation in the Arabidopsis hypocotyl. Here we provide an overview of the environmental and genetic factors controlling hypocotyl-born AR and we summarize how AR formation and the regulating factors of this organogenesis are distinct from LR induction.
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Affiliation(s)
| | | | - Danny Geelen
- Department of Plant Production, Faculty of Bioscience Engineering, Ghent UniversityGhent, Belgium
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309
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Zhang Y, Paschold A, Marcon C, Liu S, Tai H, Nestler J, Yeh CT, Opitz N, Lanz C, Schnable PS, Hochholdinger F. The Aux/IAA gene rum1 involved in seminal and lateral root formation controls vascular patterning in maize (Zea mays L.) primary roots. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:4919-30. [PMID: 24928984 PMCID: PMC4144770 DOI: 10.1093/jxb/eru249] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The maize (Zea mays L.) Aux/IAA protein RUM1 (ROOTLESS WITH UNDETECTABLE MERISTEMS 1) controls seminal and lateral root initiation. To identify RUM1-dependent gene expression patterns, RNA-Seq of the differentiation zone of primary roots of rum1 mutants and the wild type was performed in four biological replicates. In total, 2 801 high-confidence maize genes displayed differential gene expression with Fc ≥2 and FDR ≤1%. The auxin signalling-related genes rum1, like-auxin1 (lax1), lax2, (nam ataf cuc 1 nac1), the plethora genes plt1 (plethora 1), bbm1 (baby boom 1), and hscf1 (heat shock complementing factor 1) and the auxin response factors arf8 and arf37 were down-regulated in the mutant rum1. All of these genes except nac1 were auxin-inducible. The maize arf8 and arf37 genes are orthologues of Arabidopsis MP/ARF5 (MONOPTEROS/ARF5), which controls the differentiation of vascular cells. Histological analyses of mutant rum1 roots revealed defects in xylem organization and the differentiation of pith cells around the xylem. Moreover, histochemical staining of enlarged pith cells surrounding late metaxylem elements demonstrated that their thickened cell walls displayed excessive lignin deposition. In line with this phenotype, rum1-dependent mis-expression of several lignin biosynthesis genes was observed. In summary, RNA-Seq of RUM1-dependent gene expression in maize primary roots, in combination with histological and histochemical analyses, revealed the specific regulation of auxin signal transduction components by RUM1 and novel functions of RUM1 in vascular development.
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Affiliation(s)
- Yanxiang Zhang
- INRES, Institute of Crop Science and Resource Conservation, Crop Functional Genomics, University of Bonn, Friedrich-Ebert-Allee 144, 53113 Bonn, Germany
| | - Anja Paschold
- INRES, Institute of Crop Science and Resource Conservation, Crop Functional Genomics, University of Bonn, Friedrich-Ebert-Allee 144, 53113 Bonn, Germany
| | - Caroline Marcon
- INRES, Institute of Crop Science and Resource Conservation, Crop Functional Genomics, University of Bonn, Friedrich-Ebert-Allee 144, 53113 Bonn, Germany
| | - Sanzhen Liu
- Department of Agronomy, Iowa State University, Ames 50011-3650, Iowa, USA
| | - Huanhuan Tai
- INRES, Institute of Crop Science and Resource Conservation, Crop Functional Genomics, University of Bonn, Friedrich-Ebert-Allee 144, 53113 Bonn, Germany
| | - Josefine Nestler
- INRES, Institute of Crop Science and Resource Conservation, Crop Functional Genomics, University of Bonn, Friedrich-Ebert-Allee 144, 53113 Bonn, Germany
| | - Cheng-Ting Yeh
- Center for Plant Genomics, Iowa State University, Ames 50011-3650, Iowa, USA
| | - Nina Opitz
- INRES, Institute of Crop Science and Resource Conservation, Crop Functional Genomics, University of Bonn, Friedrich-Ebert-Allee 144, 53113 Bonn, Germany
| | - Christa Lanz
- Department of Molecular Biology, Max-Planck-Institute for Developmental Biology, 72076 Tuebingen, Germany
| | - Patrick S Schnable
- Department of Agronomy, Iowa State University, Ames 50011-3650, Iowa, USA Center for Plant Genomics, Iowa State University, Ames 50011-3650, Iowa, USA
| | - Frank Hochholdinger
- INRES, Institute of Crop Science and Resource Conservation, Crop Functional Genomics, University of Bonn, Friedrich-Ebert-Allee 144, 53113 Bonn, Germany
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310
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Hewezi T, Piya S, Richard G, Rice JH. Spatial and temporal expression patterns of auxin response transcription factors in the syncytium induced by the beet cyst nematode Heterodera schachtii in Arabidopsis. MOLECULAR PLANT PATHOLOGY 2014; 15:730-6. [PMID: 24433277 PMCID: PMC6638651 DOI: 10.1111/mpp.12121] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Plant-parasitic cyst nematodes induce the formation of a multinucleated feeding site in the infected root, termed the syncytium. Recent studies point to key roles of the phytohormone auxin in the regulation of gene expression and establishment of the syncytium. Nevertheless, information about the spatiotemporal expression patterns of the transcription factors that mediate auxin transcriptional responses during syncytium formation is limited. Here, we provide a gene expression map of 22 auxin response factors (ARFs) during the initiation, formation and maintenance stages of the syncytium induced by the cyst nematode Heterodera schachtii in Arabidopsis. We observed distinct and overlapping expression patterns of ARFs throughout syncytium development phases. We identified a set of ARFs whose expression is predominantly located inside the developing syncytium, whereas others are expressed in the neighbouring cells, presumably to initiate specific transcriptional programmes required for their incorporation within the developing syncytium. Our analyses also point to a role of certain ARFs in determining the maximum size of the syncytium. In addition, several ARFs were found to be highly expressed in fully developed syncytia, suggesting a role in maintaining the functional phenotype of mature syncytia. The dynamic distribution and overlapping expression patterns of various ARFs seem to be essential characteristics of ARF activity during syncytium development.
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Affiliation(s)
- Tarek Hewezi
- Department of Plant Sciences, University of Tennessee, Knoxville, TN, 37996, USA
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311
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Huang JB, Liu H, Chen M, Li X, Wang M, Yang Y, Wang C, Huang J, Liu G, Liu Y, Xu J, Cheung AY, Tao LZ. ROP3 GTPase contributes to polar auxin transport and auxin responses and is important for embryogenesis and seedling growth in Arabidopsis. THE PLANT CELL 2014; 26:3501-18. [PMID: 25217509 PMCID: PMC4213153 DOI: 10.1105/tpc.114.127902] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 08/12/2014] [Accepted: 08/22/2014] [Indexed: 05/18/2023]
Abstract
ROP GTPases are crucial for the establishment of cell polarity and for controlling responses to hormones and environmental signals in plants. In this work, we show that ROP3 plays important roles in embryo development and auxin-dependent plant growth. Loss-of-function and dominant-negative (DN) mutations in ROP3 induced a spectrum of similar defects starting with altered cell division patterning during early embryogenesis to postembryonic auxin-regulated growth and developmental responses. These resulted in distorted embryo development, defective organ formation, retarded root gravitropism, and reduced auxin-dependent hypocotyl elongation. Our results showed that the expression of AUXIN RESPONSE FACTOR5/MONOPTEROS and root master regulators PLETHORA1 (PLT1) and PLT2 was reduced in DN-rop3 mutant embryos, accounting for some of the observed patterning defects. ROP3 mutations also altered polar localization of auxin efflux proteins (PINs) at the plasma membrane (PM), thus disrupting auxin maxima in the root. Notably, ROP3 is induced by auxin and prominently detected in root stele cells, an expression pattern similar to those of several stele-enriched PINs. Our results demonstrate that ROP3 is important for maintaining the polarity of PIN proteins at the PM, which in turn ensures polar auxin transport and distribution, thereby controlling plant patterning and auxin-regulated responses.
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Affiliation(s)
- Jia-bao Huang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Huili Liu
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Min Chen
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Xiaojuan Li
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Mingyan Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Yali Yang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Chunling Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Jiaqing Huang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Guolan Liu
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Yuting Liu
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Jian Xu
- Department of Biological Sciences and NUS Centre for BioImaging Sciences, National University of Singapore, Singapore 117543
| | - Alice Y Cheung
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Li-zhen Tao
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
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312
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Gibbs DJ, Voß U, Harding SA, Fannon J, Moody LA, Yamada E, Swarup K, Nibau C, Bassel GW, Choudhary A, Lavenus J, Bradshaw SJ, Stekel DJ, Bennett MJ, Coates JC. AtMYB93 is a novel negative regulator of lateral root development in Arabidopsis. THE NEW PHYTOLOGIST 2014; 203:1194-1207. [PMID: 24902892 PMCID: PMC4286813 DOI: 10.1111/nph.12879] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 05/07/2014] [Indexed: 05/18/2023]
Abstract
Plant root system plasticity is critical for survival in changing environmental conditions. One important aspect of root architecture is lateral root development, a complex process regulated by hormone, environmental and protein signalling pathways. Here we show, using molecular genetic approaches, that the MYB transcription factor AtMYB93 is a novel negative regulator of lateral root development in Arabidopsis. We identify AtMYB93 as an interaction partner of the lateral-root-promoting ARABIDILLO proteins. Atmyb93 mutants have faster lateral root developmental progression and enhanced lateral root densities, while AtMYB93-overexpressing lines display the opposite phenotype. AtMYB93 is expressed strongly, specifically and transiently in the endodermal cells overlying early lateral root primordia and is additionally induced by auxin in the basal meristem of the primary root. Furthermore, Atmyb93 mutant lateral root development is insensitive to auxin, indicating that AtMYB93 is required for normal auxin responses during lateral root development. We propose that AtMYB93 is part of a novel auxin-induced negative feedback loop stimulated in a select few endodermal cells early during lateral root development, ensuring that lateral roots only develop when absolutely required. Putative AtMYB93 homologues are detected throughout flowering plants and represent promising targets for manipulating root systems in diverse crop species.
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Affiliation(s)
- Daniel J Gibbs
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Ute Voß
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK
| | - Susan A Harding
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Jessica Fannon
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Laura A Moody
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Erika Yamada
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Kamal Swarup
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK
| | - Candida Nibau
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - George W Bassel
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Anushree Choudhary
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Julien Lavenus
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK
| | - Susan J Bradshaw
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Dov J Stekel
- School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK
| | - Malcolm J Bennett
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK
| | - Juliet C Coates
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
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313
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Wieczorek K, Elashry A, Quentin M, Grundler FMW, Favery B, Seifert GJ, Bohlmann H. A distinct role of pectate lyases in the formation of feeding structures induced by cyst and root-knot nematodes. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:901-12. [PMID: 24905398 DOI: 10.1094/mpmi-01-14-0005-r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Pectin in the primary plant cell wall is thought to be responsible for its porosity, charge density, and microfibril spacing and is the main component of the middle lamella. Plant-parasitic nematodes secrete cell wall-degrading enzymes that macerate the plant tissue, facilitating the penetration and migration within the roots. In sedentary endoparasitic nematodes, these enzymes are released only during the migration of infective juveniles through the root. Later, nematodes manipulate the expression of host plant genes, including various cell wall enzymes, in order to induce specific feeding sites. In this study, we investigated expression of two Arabidopsis pectate lyase-like genes (PLL), PLL18 (At3g27400) and PLL19 (At4g24780), together with pectic epitopes with different degrees of methylesterification in both syncytia induced by the cyst nematode Heterodera schachtii and giant cells induced by the root-knot nematode Meloidogyne incognita. We confirmed upregulation of PLL18 and PLL19 in both types of feeding sites with quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) and in situ RT-PCR. Furthermore, the functional analysis of mutants demonstrated the important role of both PLL genes in the development and maintenance of syncytia but not giant cells. Our results show that both enzymes play distinct roles in different infected root tissues as well as during parasitism of different nematodes.
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314
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Balzan S, Johal GS, Carraro N. The role of auxin transporters in monocots development. FRONTIERS IN PLANT SCIENCE 2014; 5:393. [PMID: 25177324 PMCID: PMC4133927 DOI: 10.3389/fpls.2014.00393] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 07/23/2014] [Indexed: 05/04/2023]
Abstract
Auxin is a key regulator of plant growth and development, orchestrating cell division, elongation and differentiation, embryonic development, root and stem tropisms, apical dominance, and transition to flowering. Auxin levels are higher in undifferentiated cell populations and decrease following organ initiation and tissue differentiation. This differential auxin distribution is achieved by polar auxin transport (PAT) mediated by auxin transport proteins. There are four major families of auxin transporters in plants: PIN-FORMED (PIN), ATP-binding cassette family B (ABCB), AUXIN1/LIKE-AUX1s, and PIN-LIKES. These families include proteins located at the plasma membrane or at the endoplasmic reticulum (ER), which participate in auxin influx, efflux or both, from the apoplast into the cell or from the cytosol into the ER compartment. Auxin transporters have been largely studied in the dicotyledon model species Arabidopsis, but there is increasing evidence of their role in auxin regulated development in monocotyledon species. In monocots, families of auxin transporters are enlarged and often include duplicated genes and proteins with high sequence similarity. Some of these proteins underwent sub- and neo-functionalization with substantial modification to their structure and expression in organs such as adventitious roots, panicles, tassels, and ears. Most of the present information on monocot auxin transporters function derives from studies conducted in rice, maize, sorghum, and Brachypodium, using pharmacological applications (PAT inhibitors) or down-/up-regulation (over-expression and RNA interference) of candidate genes. Gene expression studies and comparison of predicted protein structures have also increased our knowledge of the role of PAT in monocots. However, knockout mutants and functional characterization of single genes are still scarce and the future availability of such resources will prove crucial to elucidate the role of auxin transporters in monocots development.
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Affiliation(s)
- Sara Balzan
- Department of Agronomy, Animals, Food, Natural Resources and Environment, Agripolis, University of PadovaPadova, Italy
| | - Gurmukh S. Johal
- Department of Botany and Plant Pathology, Purdue UniversityWest Lafayette, IN, USA
| | - Nicola Carraro
- Department of Agronomy, Purdue UniversityWest Lafayette, IN, USA
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315
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Gläßer C, Haberer G, Finkemeier I, Pfannschmidt T, Kleine T, Leister D, Dietz KJ, Häusler RE, Grimm B, Mayer KFX. Meta-analysis of retrograde signaling in Arabidopsis thaliana reveals a core module of genes embedded in complex cellular signaling networks. MOLECULAR PLANT 2014; 7:1167-90. [PMID: 24719466 DOI: 10.1093/mp/ssu042] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Plastid-to-nucleus signaling is essential for the coordination and adjustment of cellular metabolism in response to environmental and developmental cues of plant cells. A variety of operational retrograde signaling pathways have been described that are thought to be triggered by reactive oxygen species, photosynthesis redox imbalance, tetrapyrrole intermediates, and other metabolic traits. Here we report a meta-analysis based on transcriptome and protein interaction data. Comparing the output of these pathways reveals the commonalities and peculiarities stimulated by six different sources impinging on operational retrograde signaling. Our study provides novel insights into the interplay of these pathways, supporting the existence of an as-yet unknown core response module of genes being regulated under all conditions tested. Our analysis further highlights affiliated regulatory cis-elements and classifies abscisic acid and auxin-based signaling as secondary components involved in the response cascades following a plastidial signal. Our study provides a global analysis of structure and interfaces of different pathways involved in plastid-to-nucleus signaling and a new view on this complex cellular communication network.
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Affiliation(s)
- Christine Gläßer
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Bioinformatics and Systems Biology (IBIS), Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany
| | - Georg Haberer
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Bioinformatics and Systems Biology (IBIS), Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany
| | - Iris Finkemeier
- Biozentrum der LMU München, Department of Biologie I-Botanik, Großhaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany
| | - Thomas Pfannschmidt
- Friedrich-Schiller-Universität Jena, Institut für Allgemeine Botanik und Pflanzenphysiologie, Dornburger Str. 159, D-07743 Jena, Germany Laboratoire de Physiologie Cellulaire Végétale (LPCV), CEA/CNRS/UJF iRTSV, CEA Grenoble 17, rue des Martyrs, 38054 Grenoble cedex 9, France
| | - Tatjana Kleine
- Biozentrum der LMU München, Department of Biologie I-Botanik, Großhaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany
| | - Dario Leister
- Biozentrum der LMU München, Department of Biologie I-Botanik, Großhaderner Str. 2-4, D-82152 Planegg-Martinsried, Germany
| | - Karl-Josef Dietz
- Biochemistry and Physiology of Plants, Faculty of Biology, Bielefeld University, Universitätsstraße 25, D-33615 Bielefeld, Germany
| | - Rainer Erich Häusler
- University of Cologne, Botanical Institute, Cologne Biocenter, Zülpicher Str. 47B, D-50674 Cologne, Germany
| | - Bernhard Grimm
- Humboldt-Universität zu Berlin, Institut für Biologie, AG Pflanzenphysiologie, Philippstrasse 13, D-10115 Berlin, Germany
| | - Klaus Franz Xaver Mayer
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Bioinformatics and Systems Biology (IBIS), Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany
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316
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Kajala K, Ramakrishna P, Fisher A, C. Bergmann D, De Smet I, Sozzani R, Weijers D, Brady SM. Omics and modelling approaches for understanding regulation of asymmetric cell divisions in arabidopsis and other angiosperm plants. ANNALS OF BOTANY 2014; 113:1083-1105. [PMID: 24825294 PMCID: PMC4030820 DOI: 10.1093/aob/mcu065] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 03/06/2014] [Indexed: 05/23/2023]
Abstract
BACKGROUND Asymmetric cell divisions are formative divisions that generate daughter cells of distinct identity. These divisions are coordinated by either extrinsic ('niche-controlled') or intrinsic regulatory mechanisms and are fundamentally important in plant development. SCOPE This review describes how asymmetric cell divisions are regulated during development and in different cell types in both the root and the shoot of plants. It further highlights ways in which omics and modelling approaches have been used to elucidate these regulatory mechanisms. For example, the regulation of embryonic asymmetric divisions is described, including the first divisions of the zygote, formative vascular divisions and divisions that give rise to the root stem cell niche. Asymmetric divisions of the root cortex endodermis initial, pericycle cells that give rise to the lateral root primordium, procambium, cambium and stomatal cells are also discussed. Finally, a perspective is provided regarding the role of other hormones or regulatory molecules in asymmetric divisions, the presence of segregated determinants and the usefulness of modelling approaches in understanding network dynamics within these very special cells. CONCLUSIONS Asymmetric cell divisions define plant development. High-throughput genomic and modelling approaches can elucidate their regulation, which in turn could enable the engineering of plant traits such as stomatal density, lateral root development and wood formation.
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Affiliation(s)
- Kaisa Kajala
- Department of Plant Biology and Genome Center, UC Davis, Davis, CA 95616, USA
| | - Priya Ramakrishna
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, UK
| | - Adam Fisher
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Dominique C. Bergmann
- Howard Hughes Medical Institute and Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Ive De Smet
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, UK
- Department of Plant Systems Biology, VIB, Technologiepark 927, B-9052 Ghent, Belgium
- Department of Plant Biotechnology and Genetics, Ghent University, Technologiepark 927, B-9052 Ghent, Belgium
| | - Rosangela Sozzani
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703HA Wageningen, The Netherlands
| | - Siobhan M. Brady
- Department of Plant Biology and Genome Center, UC Davis, Davis, CA 95616, USA
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317
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Steinwand BJ, Xu S, Polko JK, Doctor SM, Westafer M, Kieber JJ. Alterations in auxin homeostasis suppress defects in cell wall function. PLoS One 2014; 9:e98193. [PMID: 24859261 PMCID: PMC4032291 DOI: 10.1371/journal.pone.0098193] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 04/30/2014] [Indexed: 11/30/2022] Open
Abstract
The plant cell wall is a highly dynamic structure that changes in response to both environmental and developmental cues. It plays important roles throughout plant growth and development in determining the orientation and extent of cell expansion, providing structural support and acting as a barrier to pathogens. Despite the importance of the cell wall, the signaling pathways regulating its function are not well understood. Two partially redundant leucine-rich-repeat receptor-like kinases (LRR-RLKs), FEI1 and FEI2, regulate cell wall function in Arabidopsis thaliana roots; disruption of the FEIs results in short, swollen roots as a result of decreased cellulose synthesis. We screened for suppressors of this swollen root phenotype and identified two mutations in the putative mitochondrial pyruvate dehydrogenase E1α homolog, IAA-Alanine Resistant 4 (IAR4). Mutations in IAR4 were shown previously to disrupt auxin homeostasis and lead to reduced auxin function. We show that mutations in IAR4 suppress a subset of the fei1 fei2 phenotypes. Consistent with the hypothesis that the suppression of fei1 fei2 by iar4 is the result of reduced auxin function, disruption of the WEI8 and TAR2 genes, which decreases auxin biosynthesis, also suppresses fei1 fei2. In addition, iar4 suppresses the root swelling and accumulation of ectopic lignin phenotypes of other cell wall mutants, including procuste and cobra. Further, iar4 mutants display decreased sensitivity to the cellulose biosynthesis inhibitor isoxaben. These results establish a role for IAR4 in the regulation of cell wall function and provide evidence of crosstalk between the cell wall and auxin during cell expansion in the root.
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Affiliation(s)
- Blaire J. Steinwand
- Biology Department, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Shouling Xu
- Biology Department, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Joanna K. Polko
- Biology Department, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Stephanie M. Doctor
- Biology Department, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Mike Westafer
- Biology Department, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Joseph J. Kieber
- Biology Department, University of North Carolina, Chapel Hill, North Carolina, United States of America
- * E-mail:
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318
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Suzuki H, Matano N, Nishimura T, Koshiba T. A 2,4-dichlorophenoxyacetic acid analog screened using a maize coleoptile system potentially inhibits indole-3-acetic acid influx in Arabidopsis thaliana. PLANT SIGNALING & BEHAVIOR 2014; 9:29077. [PMID: 24800738 PMCID: PMC4091417 DOI: 10.4161/psb.29077] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 04/30/2014] [Accepted: 04/30/2014] [Indexed: 05/30/2023]
Abstract
Studies using inhibitors of indole-3-acetic acid (IAA) transport, not only for efflux but influx carriers, provide many aspects of auxin physiology in plants. 1-Naphtoxyacetic acid (1-NOA), an analog of the synthetic auxin 1-N-naphtalene acetic acid (NAA), inhibits the IAA influx carrier AUX1. However, 1-NOA also shows auxin activity because of its structural similarity to NAA. In this study, we have identified another candidate inhibitor of the IAA influx carrier. The compound, "7-B3; ethyl 2-[(2-chloro-4-nitrophenyl)thio]acetate," is a 2,4-dichlorophenoxyacetic acid (2,4-D) analog. At high concentrations (> 300 µM), 7-B3 slightly reduced IAA transport and tropic curvature of maize coleoptiles, whereas lower concentrations had almost no effect. We have analyzed the effects of 7-B3 on Arabidopsis thaliana seedlings. 7-B3 rescued the 2,4-D-inhibited root elongation, but not the NAA-inhibited root elongation. The effect of 7-B3 was weaker than that of 1-NOA. Both 1-NOA and 7-B3 inhibited DR5::GUS expression induced by IAA and 2,4-D, but not that induced by NAA. At high concentrations, 1-NOA exhibited auxin activity, but 7-B3 did not. Furthermore, 7-B3 inhibited apical hook formation in etiolated seedlings more effectively than did 1-NOA. These results indicate that 7-B3 is a potential inhibitor of IAA influx that has almost no effect on IAA efflux or auxin signaling.
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319
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Goh T, Voβ U, Farcot E, Bennett MJ, Bishopp A. Systems biology approaches to understand the role of auxin in root growth and development. PHYSIOLOGIA PLANTARUM 2014; 151:73-82. [PMID: 24494934 DOI: 10.1111/ppl.12162] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 01/28/2014] [Accepted: 01/30/2014] [Indexed: 05/08/2023]
Abstract
The past decade has seen major advances in our understanding of auxin regulated root growth and developmental processes. Key genes have been identified that regulate and/or mediate auxin homeostasis, transport, perception and response. The molecular and biochemical reactions that underpin auxin signalling are non-linear, with feed-forward and feedback loops contributing to the robustness of the system. As our knowledge of auxin biology becomes increasingly complex and their outputs less intuitive, modelling is set to become much more important. For the last several decades modelling efforts have focused on auxin transport and, latterly, on auxin response. Recently researchers have employed multi-scale modelling approaches to predict emergent properties at the tissue and organ scales. Such innovative modelling approaches are proving very promising, revealing new mechanistic insights about how auxin functions within a multicellular context to control plant growth and development. In this review we initially describe examples of models capturing auxin transport and response pathways, and then discuss increasingly complex models that integrate multiple hormone response pathways, tissues and/or scales.
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Affiliation(s)
- Tatsuaki Goh
- Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Loughborough, UK; Graduate School of Science, Kobe University, Kobe, Hyogo, Japan
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320
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Ursache R, Miyashima S, Chen Q, Vatén A, Nakajima K, Carlsbecker A, Zhao Y, Helariutta Y, Dettmer J. Tryptophan-dependent auxin biosynthesis is required for HD-ZIP III-mediated xylem patterning. Development 2014; 141:1250-9. [PMID: 24595288 DOI: 10.1242/dev.103473] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The development and growth of higher plants is highly dependent on the conduction of water and minerals throughout the plant by xylem vessels. In Arabidopsis roots the xylem is organized as an axis of cell files with two distinct cell fates: the central metaxylem and the peripheral protoxylem. During vascular development, high and low expression levels of the class III HD-ZIP transcription factors promote metaxylem and protoxylem identities, respectively. Protoxylem specification is determined by both mobile, ground tissue-emanating miRNA165/6 species, which downregulate, and auxin concentrated by polar transport, which promotes HD-ZIP III expression. However, the factors promoting high HD-ZIP III expression for metaxylem identity have remained elusive. We show here that auxin biosynthesis promotes HD-ZIP III expression and metaxylem specification. Several auxin biosynthesis genes are expressed in the outer layers surrounding the vascular tissue in Arabidopsis root and downregulation of HD-ZIP III expression accompanied by specific defects in metaxylem development is seen in auxin biosynthesis mutants, such as trp2-12, wei8 tar2 or a quintuple yucca mutant, and in plants treated with L-kynurenine, a pharmacological inhibitor of auxin biosynthesis. Some of the patterning defects can be suppressed by synthetically elevated HD-ZIP III expression. Taken together, our results indicate that polar auxin transport, which was earlier shown to be required for protoxylem formation, is not sufficient to establish a proper xylem axis but that root-based auxin biosynthesis is additionally required.
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Affiliation(s)
- Robertas Ursache
- Institute of Biotechnology, Department of Bio and Environmental Sciences, University of Helsinki, FIN-00014, Finland
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321
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Roycewicz PS, Malamy JE. Cell wall properties play an important role in the emergence of lateral root primordia from the parent root. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:2057-69. [PMID: 24619997 PMCID: PMC3991740 DOI: 10.1093/jxb/eru056] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Plants adapt to their unique soil environments by altering the number and placement of lateral roots post-embryonic. Mutants were identified in Arabidopsis thaliana that exhibit increased lateral root formation. Eight mutants were characterized in detail and were found to have increased lateral root formation due to at least three distinct mechanisms. The causal mutation in one of these mutants was found in the XEG113 gene, recently shown to be involved in plant cell wall biosynthesis. Lateral root primordia initiation is unaltered in this mutant. In contrast, synchronization of lateral root initiation demonstrated that mutation of XEG113 increases the rate at which lateral root primordia develop and emerge to form lateral roots. The effect of the XEG113 mutation was specific to the root system and had no apparent effect on shoot growth. Screening of 17 additional cell wall mutants, altering a myriad of cell wall components, revealed that many (but not all) types of cell wall defects promote lateral root formation. These results suggest that proper cell wall biosynthesis is necessary to constrain lateral root primordia emergence. While previous reports have shown that lateral root emergence is accompanied by active remodelling of cell walls overlying the primordia, this study is the first to demonstrate that alteration of the cell wall is sufficient to promote lateral root formation. Therefore, inherent cell wall properties may play a previously unappreciated role in regulation of root system architecture.
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322
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Tejos R, Sauer M, Vanneste S, Palacios-Gomez M, Li H, Heilmann M, van Wijk R, Vermeer JEM, Heilmann I, Munnik T, Friml J. Bipolar Plasma Membrane Distribution of Phosphoinositides and Their Requirement for Auxin-Mediated Cell Polarity and Patterning in Arabidopsis. THE PLANT CELL 2014; 26:2114-2128. [PMID: 24876254 PMCID: PMC4079372 DOI: 10.1105/tpc.114.126185] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 04/07/2014] [Accepted: 05/05/2014] [Indexed: 05/19/2023]
Abstract
Cell polarity manifested by asymmetric distribution of cargoes, such as receptors and transporters, within the plasma membrane (PM) is crucial for essential functions in multicellular organisms. In plants, cell polarity (re)establishment is intimately linked to patterning processes. Despite the importance of cell polarity, its underlying mechanisms are still largely unknown, including the definition and distinctiveness of the polar domains within the PM. Here, we show in Arabidopsis thaliana that the signaling membrane components, the phosphoinositides phosphatidylinositol 4-phosphate (PtdIns4P) and phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] as well as PtdIns4P 5-kinases mediating their interconversion, are specifically enriched at apical and basal polar plasma membrane domains. The PtdIns4P 5-kinases PIP5K1 and PIP5K2 are redundantly required for polar localization of specifically apical and basal cargoes, such as PIN-FORMED transporters for the plant hormone auxin. As a consequence of the polarity defects, instructive auxin gradients as well as embryonic and postembryonic patterning are severely compromised. Furthermore, auxin itself regulates PIP5K transcription and PtdIns4P and PtdIns(4,5)P2 levels, in particular their association with polar PM domains. Our results provide insight into the polar domain-delineating mechanisms in plant cells that depend on apical and basal distribution of membrane lipids and are essential for embryonic and postembryonic patterning.
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Affiliation(s)
- Ricardo Tejos
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Michael Sauer
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | - Steffen Vanneste
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
| | | | - Hongjiang Li
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Mareike Heilmann
- Department of Cellular Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Ringo van Wijk
- Swammerdam Institute for Life Sciences, Section Plant Physiology, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Joop E M Vermeer
- Swammerdam Institute for Life Sciences, Section Plant Physiology, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Ingo Heilmann
- Department of Cellular Biochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Teun Munnik
- Swammerdam Institute for Life Sciences, Section Plant Physiology, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Jiří Friml
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
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323
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Wang WS, Zhu J, Lu YT. Overexpression of AtbHLH112 suppresses lateral root emergence in Arabidopsis. FUNCTIONAL PLANT BIOLOGY : FPB 2014; 41:342-352. [PMID: 32480995 DOI: 10.1071/fp13253] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 10/14/2013] [Indexed: 06/11/2023]
Abstract
The basic/helix-loop-helix (bHLH) transcription factors are ubiquitous transcriptional regulators that control many different developmental and physiological processes in the eukaryotic kingdom. In this study, the function of AtbHLH112, an uncharacterised member of the bHLH family in Arabidopsis was investigated. Overexpression of AtbHLH112 suppressed lateral root (LR) development in Arabidopsis seedlings. Examination under the microscope revealed that abnormal lateral root primordia (LRP) with flat-head and more than four cell layers retained in the endodermal layer account for over 45% of the total number of LRP and LRs. This suggests that LRP emergence was prevented before LRP penetrated the cortical layer in the transgenic lines. Decreased auxin level within the LRP and parental root cells surrounding the LRP, as well as downregulated expression of cell-wall-remodelling (CWR) genes in the roots may contribute to the suppression of LR emergence in AtbHLH112-overexpressing lines. This finding was further supported by the observation that exogenous application of auxin recovered LR development and upregulated the expression of CWR genes in AtbHLH112-overexpressing lines.
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Affiliation(s)
- Wen-Shu Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jiang Zhu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Ying-Tang Lu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
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324
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Ma W, Li J, Qu B, He X, Zhao X, Li B, Fu X, Tong Y. Auxin biosynthetic gene TAR2 is involved in low nitrogen-mediated reprogramming of root architecture in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 78:70-9. [PMID: 24460551 DOI: 10.1111/tpj.12448] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 01/10/2014] [Accepted: 01/17/2014] [Indexed: 05/03/2023]
Abstract
In plants, the plasticity of root architecture in response to nitrogen availability largely determines nitrogen acquisition efficiency. One poorly understood root growth response to low nitrogen availability is an observed increase in the number and length of lateral roots (LRs). Here, we show that low nitrogen-induced Arabidopsis LR growth depends on the function of the auxin biosynthesis gene TAR2 (tryptophan aminotransferase related 2). TAR2 was expressed in the pericycle and the vasculature of the mature root zone near the root tip, and was induced under low nitrogen conditions. In wild type plants, low nitrogen stimulated auxin accumulation in the non-emerged LR primordia with more than three cell layers and LR emergence. Conversely, these low nitrogen-mediated auxin accumulation and root growth responses were impaired in the tar2-c null mutant. Overexpression of TAR2 increased LR numbers under both high and low nitrogen conditions. Our results suggested that TAR2 is required for reprogramming root architecture in response to low nitrogen conditions. This finding suggests a new strategy for improving nitrogen use efficiency through the engineering of TAR2 expression in roots.
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Affiliation(s)
- Wenying Ma
- The State Key Laboratory for Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
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325
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Secco D, Shou H, Whelan J, Berkowitz O. RNA-seq analysis identifies an intricate regulatory network controlling cluster root development in white lupin. BMC Genomics 2014; 15:230. [PMID: 24666749 PMCID: PMC4028058 DOI: 10.1186/1471-2164-15-230] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 03/18/2014] [Indexed: 01/03/2023] Open
Abstract
Background Highly adapted plant species are able to alter their root architecture to improve nutrient uptake and thrive in environments with limited nutrient supply. Cluster roots (CRs) are specialised structures of dense lateral roots formed by several plant species for the effective mining of nutrient rich soil patches through a combination of increased surface area and exudation of carboxylates. White lupin is becoming a model-species allowing for the discovery of gene networks involved in CR development. A greater understanding of the underlying molecular mechanisms driving these developmental processes is important for the generation of smarter plants for a world with diminishing resources to improve food security. Results RNA-seq analyses for three developmental stages of the CR formed under phosphorus-limited conditions and two of non-cluster roots have been performed for white lupin. In total 133,045,174 high-quality paired-end reads were used for a de novo assembly of the root transcriptome and merged with LAGI01 (Lupinus albus gene index) to generate an improved LAGI02 with 65,097 functionally annotated contigs. This was followed by comparative gene expression analysis. We show marked differences in the transcriptional response across the various cluster root stages to adjust to phosphate limitation by increasing uptake capacity and adjusting metabolic pathways. Several transcription factors such as PLT, SCR, PHB, PHV or AUX/IAA with a known role in the control of meristem activity and developmental processes show an increased expression in the tip of the CR. Genes involved in hormonal responses (PIN, LAX, YUC) and cell cycle control (CYCA/B, CDK) are also differentially expressed. In addition, we identify primary transcripts of miRNAs with established function in the root meristem. Conclusions Our gene expression analysis shows an intricate network of transcription factors and plant hormones controlling CR initiation and formation. In addition, functional differences between the different CR developmental stages in the acclimation to phosphorus starvation have been identified.
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Affiliation(s)
| | | | | | - Oliver Berkowitz
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, WA 6009, Australia.
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326
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Seifertová D, Skůpa P, Rychtář J, Laňková M, Pařezová M, Dobrev PI, Hoyerová K, Petrášek J, Zažímalová E. Characterization of transmembrane auxin transport in Arabidopsis suspension-cultured cells. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:429-37. [PMID: 24594395 DOI: 10.1016/j.jplph.2013.09.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Revised: 09/24/2013] [Accepted: 09/28/2013] [Indexed: 05/21/2023]
Abstract
Polar auxin transport is a crucial process for control and coordination of plant development. Studies of auxin transport through plant tissues and organs showed that auxin is transported by a combination of phloem flow and the active, carrier-mediated cell-to-cell transport. Since plant organs and even tissues are too complex for determination of the kinetics of carrier-mediated auxin uptake and efflux on the cellular level, simplified models of cell suspension cultures are often used, and several tobacco cell lines have been established for auxin transport assays. However, there are very few data available on the specificity and kinetics of auxin transport across the plasma membrane for Arabidopsis thaliana suspension-cultured cells. In this report, the characteristics of carrier-mediated uptake (influx) and efflux for the native auxin indole-3-acetic acid and synthetic auxins, naphthalene-1-acetic and 2,4-dichlorophenoxyacetic acids (NAA and 2,4-D, respectively) in A. thaliana ecotype Landsberg erecta suspension-cultured cells (LE line) are provided. By auxin competition assays and inhibitor treatments, we show that, similarly to tobacco cells, uptake carriers have high affinity towards 2,4-D and that NAA is a good tool for studies of auxin efflux in LE cells. In contrast to tobacco cells, metabolic profiling showed that only a small proportion of NAA is metabolized in LE cells. These results show that the LE cell line is a useful experimental system for measurements of kinetics of auxin carriers on the cellular level that is complementary to tobacco cells.
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Affiliation(s)
- Daniela Seifertová
- Institute of Experimental Botany ASCR, Rozvojová 263, 165 02 Prague 6, Czech Republic.
| | - Petr Skůpa
- Institute of Experimental Botany ASCR, Rozvojová 263, 165 02 Prague 6, Czech Republic.
| | - Jan Rychtář
- Department of Mathematics and Statistics, The University of North Carolina at Greensboro, 130 Petty Building, NC 27403, USA.
| | - Martina Laňková
- Institute of Experimental Botany ASCR, Rozvojová 263, 165 02 Prague 6, Czech Republic.
| | - Markéta Pařezová
- Institute of Experimental Botany ASCR, Rozvojová 263, 165 02 Prague 6, Czech Republic.
| | - Petre I Dobrev
- Institute of Experimental Botany ASCR, Rozvojová 263, 165 02 Prague 6, Czech Republic.
| | - Klára Hoyerová
- Institute of Experimental Botany ASCR, Rozvojová 263, 165 02 Prague 6, Czech Republic.
| | - Jan Petrášek
- Institute of Experimental Botany ASCR, Rozvojová 263, 165 02 Prague 6, Czech Republic.
| | - Eva Zažímalová
- Institute of Experimental Botany ASCR, Rozvojová 263, 165 02 Prague 6, Czech Republic.
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327
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Lee SW, Feugier FG, Morishita Y. Canalization-based vein formation in a growing leaf. J Theor Biol 2014; 353:104-20. [PMID: 24632445 DOI: 10.1016/j.jtbi.2014.03.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 02/25/2014] [Accepted: 03/03/2014] [Indexed: 11/24/2022]
Abstract
Vein formation is an important process in plant leaf development. The phytohormone auxin is known as the most important molecule for the control of venation patterning; and the canalization model, in which cells experiencing higher auxin flux differentiate into specific cells for auxin transportation, is widely accepted. To date, several mathematical models based on the canalization hypothesis have been proposed that have succeeded in reproducing vein patterns similar to those observed in actual leaves. However, most previous studies focused on patterning in fixed domains, and, in a few exceptional studies, limited tissue growth - such as cell proliferation at leaf margins and small deformations without large changes in cell number - were dealt with. Considering that, in actual leaf development, venation patterning occurs in an exponentially growing tissue, whether the canalization hypothesis still applies is an important issue to be addressed. In this study, we first show through a pilot simulation that the coupling of chemical dynamics for canalization and tissue growth as independent models cannot reproduce normal venation patterning. We then examine conditions sufficient for achieving normal patterning in a growing leaf by introducing various constraints on chemical dynamics, tissue growth, and cell mechanics; in doing so, we found that auxin flux- or differentiation-dependent modification of the cell cycle and elasticity of cell edges are essential. The predictions given by our simulation study will serve as guideposts in experiments aimed at finding the key factors for achieving normal venation patterning in developing plant leaves.
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Affiliation(s)
- Sang-Woo Lee
- Laboratory for Developmental Morphogeometry, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi Chuo-ku, Kobe 650-0047, Japan; Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan
| | | | - Yoshihiro Morishita
- Laboratory for Developmental Morphogeometry, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi Chuo-ku, Kobe 650-0047, Japan.
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328
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Passaia G, Queval G, Bai J, Margis-Pinheiro M, Foyer CH. The effects of redox controls mediated by glutathione peroxidases on root architecture in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:1403-13. [PMID: 24470466 PMCID: PMC3969529 DOI: 10.1093/jxb/ert486] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Glutathione peroxidases (GPXs) fulfil important functions in oxidative signalling and protect against the adverse effects of excessive oxidation. However, there has been no systematic characterization of the functions of the different GPX isoforms in plants. The roles of the different members of the Arabidopsis thaliana GPX gene (AtGPX) family were therefore investigated using gpx1, gpx2, gpx3, gpx4, gpx6, gpx7, and gpx8 T-DNA insertion mutant lines. The shoot phenotypes were largely similar in all genotypes, with small differences from the wild type observed only in the gpx2, gpx3, gpx7, and gpx8 mutants. In contrast, all the mutants showed altered root phenotypes compared with the wild type. The gpx1, gpx4, gpx6, gpx7, and gpx8 mutants had a significantly greater lateral root density (LRD) than the wild type. Conversely, the gpx2 and gpx3 mutants had significantly lower LRD values than the wild type. Auxin increased the LRD in all genotypes, but the effect of auxin was significantly greater in the gpx1, gpx4, and gpx7 mutants than in the wild type. The application of auxin increased GPX4 and GPX7 transcripts, but not GPX1 mRNAs in the roots of wild-type plants. The synthetic strigolactone GR24 and abscisic acid (ABA) decreased LRD to a similar extent in all genotypes, except gpx6, which showed increased sensitivity to ABA. These data not only demonstrate the importance of redox controls mediated by AtGPXs in the control of root architecture but they also show that the plastid-localized GPX1 and GPX7 isoforms are required for the hormone-mediated control of lateral root development.
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Affiliation(s)
- Gisele Passaia
- Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
- Depto. Genética, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, Prédio 43.312, CEP 91501–970 Porto Alegre, RS, Brazil
| | - Guillaume Queval
- Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Juan Bai
- Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
- College of Life Science, Northwest A&F University, Shaanxi 712100, China
| | - Marcia Margis-Pinheiro
- Depto. Genética, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, Prédio 43.312, CEP 91501–970 Porto Alegre, RS, Brazil
| | - Christine H. Foyer
- Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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329
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Giehl RFH, Gruber BD, von Wirén N. It's time to make changes: modulation of root system architecture by nutrient signals. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:769-78. [PMID: 24353245 DOI: 10.1093/jxb/ert421] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Root growth and development are of outstanding importance for the plant's ability to acquire water and nutrients from different soil horizons. To cope with fluctuating nutrient availabilities, plants integrate systemic signals pertaining to their nutritional status into developmental pathways that regulate the spatial arrangement of roots. Changes in the plant nutritional status and external nutrient supply modulate root system architecture (RSA) over time and determine the degree of root plasticity which is based on variations in the number, extension, placement, and growth direction of individual components of the root system. Roots also sense the local availability of some nutrients, thereby leading to nutrient-specific modifications in RSA, that result from the integration of systemic and local signals into the root developmental programme at specific steps. An in silico analysis of nutrient-responsive genes involved in root development showed that the majority of these specifically responded to the deficiency of individual nutrients while a minority responded to more than one nutrient deficiency. Such an analysis provides an interesting starting point for the identification of the molecular players underlying the sensing and transduction of the nutrient signals that mediate changes in the development and architecture of root systems.
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Affiliation(s)
- Ricardo F H Giehl
- Molecular Plant Nutrition, Leibniz Institute of Plant Genetics and Crop Plant Research, Corrensstr. 3, D-06466, Gatersleben, Germany
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330
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Band LR, Wells DM, Fozard JA, Ghetiu T, French AP, Pound MP, Wilson MH, Yu L, Li W, Hijazi HI, Oh J, Pearce SP, Perez-Amador MA, Yun J, Kramer E, Alonso JM, Godin C, Vernoux T, Hodgman TC, Pridmore TP, Swarup R, King JR, Bennett MJ. Systems analysis of auxin transport in the Arabidopsis root apex. THE PLANT CELL 2014; 26:862-75. [PMID: 24632533 PMCID: PMC4001398 DOI: 10.1105/tpc.113.119495] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 01/06/2014] [Accepted: 02/14/2014] [Indexed: 05/17/2023]
Abstract
Auxin is a key regulator of plant growth and development. Within the root tip, auxin distribution plays a crucial role specifying developmental zones and coordinating tropic responses. Determining how the organ-scale auxin pattern is regulated at the cellular scale is essential to understanding how these processes are controlled. In this study, we developed an auxin transport model based on actual root cell geometries and carrier subcellular localizations. We tested model predictions using the DII-VENUS auxin sensor in conjunction with state-of-the-art segmentation tools. Our study revealed that auxin efflux carriers alone cannot create the pattern of auxin distribution at the root tip and that AUX1/LAX influx carriers are also required. We observed that AUX1 in lateral root cap (LRC) and elongating epidermal cells greatly enhance auxin's shootward flux, with this flux being predominantly through the LRC, entering the epidermal cells only as they enter the elongation zone. We conclude that the nonpolar AUX1/LAX influx carriers control which tissues have high auxin levels, whereas the polar PIN carriers control the direction of auxin transport within these tissues.
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Affiliation(s)
- Leah R. Band
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Darren M. Wells
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - John A. Fozard
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Teodor Ghetiu
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Andrew P. French
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Michael P. Pound
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Michael H. Wilson
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Lei Yu
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Wenda Li
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Hussein I. Hijazi
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Jaesung Oh
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Simon P. Pearce
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Miguel A. Perez-Amador
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia–Consejo Superior de Investigaciones Científicas, Ciudad Politécnica de la Innovación, 46022 Valencia, Spain
| | - Jeonga Yun
- Department of Genetics, North Carolina State University, Raleigh, North Carolina 27695
| | - Eric Kramer
- Physics Department, Bard College at Simon’s Rock, Great Barrington, Massachusetts 01230
| | - Jose M. Alonso
- Department of Genetics, North Carolina State University, Raleigh, North Carolina 27695
| | - Christophe Godin
- Virtual Plants Project Team, Unité Mixte de Recherche, Amélioration Génétique des Plantes Méditerranéennes et Tropicales, Institut National de Recherche en Informatique et en Automatique/Centre de Coopération Internationale en Recherche Agronomique pour le Développement, 34095 Montpellier, France
| | - Teva Vernoux
- Laboratoire de Reproduction et Developpement des Plantes, CNRS, INRA, Ecole Normale Supérieure Lyon, Université Claude Bernard Lyon 1, Université de Lyon, 69364 Lyon, France
| | - T. Charlie Hodgman
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Tony P. Pridmore
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Ranjan Swarup
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - John R. King
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
| | - Malcolm J. Bennett
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
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331
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332
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Herrbach V, Remblière C, Gough C, Bensmihen S. Lateral root formation and patterning in Medicago truncatula. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:301-10. [PMID: 24148318 DOI: 10.1016/j.jplph.2013.09.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 09/06/2013] [Accepted: 09/06/2013] [Indexed: 05/08/2023]
Abstract
The plant root system is crucial for anchorage and nutrition, and has a major role in plant adaptation, as well as in interactions with soil micro-organisms. Despite the agronomical and ecological importance of legume plants, whose roots can interact symbiotically with soil bacteria called rhizobia that fix atmospheric dinitrogen, and the evidence that lateral root (LR) development programmes are intercepted and influenced by symbiotic organisms, very little is known concerning the cellular and molecular events governing LR development in legumes. To better understand the interconnections between LR formation and symbiotic processes triggered by rhizobia or symbiotic molecules such as lipo-chitooligosaccharides (LCOs), we first need a detailed description of LR development mechanisms in legumes. Using thin sections, we have described the cellular events leading to the formation of a new LR primordium (LRP) in Medicago truncatula, and divided them into seven stages prior to LR emergence. To monitor auxin accumulation we generated transgenic DR5:GUS and DR5:VENUS-N7 reporter lines of M. truncatula, and used them to analyze early stages of LR development. Interesting differences were observed for LR ontogeny compared to Arabidopsis thaliana. Notably, we observed endodermal and cortical contributions to LRP formation, and the associated DR5:GUS expression profile indicated that endodermal and cortical cell divisions were correlated with auxin accumulation. As described for A. thaliana, we observed a preferential zone for LR initiation at 4.45 mm from the root tip. Finally, we studied LR emergence and showed that a significant proportion of new LRP do not emerge straight away and could thus be an additional source of root plasticity. Our results shed new light on the patterning and early development of LRs in M. truncatula.
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Affiliation(s)
- Violaine Herrbach
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326 Castanet-Tolosan, France; CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326 Castanet-Tolosan, France
| | - Céline Remblière
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326 Castanet-Tolosan, France; CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326 Castanet-Tolosan, France
| | - Clare Gough
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326 Castanet-Tolosan, France; CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326 Castanet-Tolosan, France
| | - Sandra Bensmihen
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326 Castanet-Tolosan, France; CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326 Castanet-Tolosan, France.
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333
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Song Y. Insight into the mode of action of 2,4-dichlorophenoxyacetic acid (2,4-D) as an herbicide. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2014; 56:106-13. [PMID: 24237670 DOI: 10.1111/jipb.12131] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 11/06/2013] [Indexed: 05/10/2023]
Abstract
2,4-Dichlorophenoxyacetic acid (2,4-D) was the first synthetic herbicide to be commercially developed and has commonly been used as a broadleaf herbicide for over 60 years. It is a selective herbicide that kills dicots without affecting monocots and mimics natural auxin at the molecular level. Physiological responses of dicots sensitive to auxinic herbicides include abnormal growth, senescence, and plant death. The identification of auxin receptors, auxin transport carriers, transcription factors response to auxin, and cross-talk among phytohormones have shed light on the molecular action mode of 2,4-D as a herbicide. Here, the molecular action mode of 2,4-D is highlighted according to the latest findings, emphasizing the physiological process, perception, and signal transduction under herbicide treatment.
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Affiliation(s)
- Yaling Song
- Key Laboratory of Tropical Plant Resource and Sustainable Use, Xishuangbanna Tropical Botanical Garden, the Chinese Academy of Sciences, Mengla, 666303, China
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334
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Quach TN, Tran LSP, Valliyodan B, Nguyen HTM, Kumar R, Neelakandan AK, Guttikonda SK, Sharp RE, Nguyen HT. Functional analysis of water stress-responsive soybean GmNAC003 and GmNAC004 transcription factors in lateral root development in arabidopsis. PLoS One 2014; 9:e84886. [PMID: 24465446 PMCID: PMC3900428 DOI: 10.1371/journal.pone.0084886] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 11/27/2013] [Indexed: 12/22/2022] Open
Abstract
In Arabidopsis, NAC (NAM, ATAF and CUC) transcription factors have been found to promote lateral root number through the auxin signaling pathway. In the present study, the role of water stress-inducible soybean GmNAC003 and GmNAC004 genes in the enhancement of lateral root development under water deficit conditions was investigated. Both genes were highly expressed in roots, leaves and flowers of soybean and were strongly induced by water stress and moderately induced by a treatment with abscisic acid (ABA). They showed a slight response to treatment with 2,4-dichlorophenoxyacetic acid (2,4-D). The transgenic Arabidopsis plants overexpressing GmNAC004 showed an increase in lateral root number and length under non-stress conditions and maintained higher lateral root number and length under mild water stress conditions compared to the wild-type (WT), while the transgenic plants overexpressing GmNAC003 did not show any response. However, LR development of GmNAC004 transgenic Arabidopsis plants was not enhanced in the water-stressed compared to the well-watered treatment. In the treatment with ABA, LR density of the GmNAC004 transgenic Arabidopsis was less suppressed than that of the WT, suggesting that GmNAC004 counteracts ABA-induced inhibition of lateral root development. In the treatment with 2,4-D, lateral root density was enhanced in both GmNAC004 transgenic Arabidopsis and WT plants but the promotion was higher in the transgenic plants. Conversely, in the treatment with naphthylphthalamic acid (NPA), lateral root density was inhibited and there was no difference in the phenotype of the GmNAC004 transgenic Arabidopsis and WT plants, indicating that auxin is required for the action of GmNAC004. Transcript analysis for a number of known auxin and ABA related genes showed that GmNAC004's role may suppress ABA signaling but promote auxin signaling to increase lateral root development in the Arabidopsis heterologous system.
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Affiliation(s)
- Truyen N. Quach
- Division of Plant Sciences, National Center for Soybean Biotechnology and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri, United States of America
| | - Lam-Son Phan Tran
- Division of Plant Sciences, National Center for Soybean Biotechnology and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri, United States of America
| | - Babu Valliyodan
- Division of Plant Sciences, National Center for Soybean Biotechnology and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri, United States of America
| | - Hanh TM. Nguyen
- Division of Plant Sciences, National Center for Soybean Biotechnology and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri, United States of America
| | - Rajesh Kumar
- Division of Plant Sciences, National Center for Soybean Biotechnology and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri, United States of America
| | - Anjanasree K. Neelakandan
- Division of Plant Sciences, National Center for Soybean Biotechnology and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri, United States of America
| | - Satish Kumar Guttikonda
- Division of Plant Sciences, National Center for Soybean Biotechnology and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri, United States of America
| | - Robert E. Sharp
- Division of Plant Sciences, National Center for Soybean Biotechnology and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri, United States of America
| | - Henry T. Nguyen
- Division of Plant Sciences, National Center for Soybean Biotechnology and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri, United States of America
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335
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Vermeer JEM, von Wangenheim D, Barberon M, Lee Y, Stelzer EHK, Maizel A, Geldner N. A spatial accommodation by neighboring cells is required for organ initiation in Arabidopsis. Science 2014; 343:178-83. [PMID: 24408432 DOI: 10.1126/science.1245871] [Citation(s) in RCA: 193] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Lateral root formation in plants can be studied as the process of interaction between chemical signals and physical forces during development. Lateral root primordia grow through overlying cell layers that must accommodate this incursion. Here, we analyze responses of the endodermis, the immediate neighbor to an initiating lateral root. Endodermal cells overlying lateral root primordia lose volume, change shape, and relinquish their tight junction-like diffusion barrier to make way for the emerging lateral root primordium. Endodermal feedback is absolutely required for initiation and growth of lateral roots, and we provide evidence that this is mediated by controlled volume loss in the endodermis. We propose that turgidity and rigid cell walls, typical of plants, impose constraints that are specifically modified for a given developmental process.
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Affiliation(s)
- Joop E M Vermeer
- Department of Plant Molecular Biology, Biophore, UNIL-Sorge, University of Lausanne, 1015 Lausanne, Switzerland
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336
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Lituiev DS, Krohn NG, Müller B, Jackson D, Hellriegel B, Dresselhaus T, Grossniklaus U. Theoretical and experimental evidence indicates that there is no detectable auxin gradient in the angiosperm female gametophyte. Development 2014; 140:4544-53. [PMID: 24194471 DOI: 10.1242/dev.098301] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The plant life cycle alternates between a diploid sporophytic and a haploid gametophytic generation. The female gametophyte (FG) of flowering plants is typically formed through three syncytial mitoses, followed by cellularisation that forms seven cells belonging to four cell types. The specification of cell fates in the FG has been suggested to depend on positional information provided by an intrinsic auxin concentration gradient. The goal of this study was to develop mathematical models that explain the formation of this gradient in a syncytium. Two factors were proposed to contribute to the maintenance of the auxin gradient in Arabidopsis FGs: polar influx at early stages and localised auxin synthesis at later stages. However, no gradient could be generated using classical, one-dimensional theoretical models under these assumptions. Thus, we tested other hypotheses, including spatial confinement by the large central vacuole, background efflux and localised degradation, and investigated the robustness of cell specification under different parameters and assumptions. None of the models led to the generation of an auxin gradient that was steep enough to allow sufficiently robust patterning. This led us to re-examine the response to an auxin gradient in developing FGs using various auxin reporters, including a novel degron-based reporter system. In agreement with the predictions of our models, auxin responses were not detectable within the FG of Arabidopsis or maize, suggesting that the effects of manipulating auxin production and response on cell fate determination might be indirect.
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Affiliation(s)
- Dmytro S Lituiev
- Institute of Plant Biology and Zürich-Basel Plant Science Center, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
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337
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Geisler M, Wang B, Zhu J. Auxin transport during root gravitropism: transporters and techniques. PLANT BIOLOGY (STUTTGART, GERMANY) 2014; 16 Suppl 1:50-7. [PMID: 23648074 DOI: 10.1111/plb.12030] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 02/28/2013] [Indexed: 05/04/2023]
Abstract
Root gravitropism is a complex, plant-specific process allowing roots to grow downward into the soil. Polar auxin transport and redistribution are essential for root gravitropism. Here we summarise our current understanding of underlying molecular mechanisms and involved transporters that establish, maintain and redirect intercellular auxin gradients as the driving force for root gravitropism. We evaluate the genetic, biochemical and cell biological approaches presently used for the analysis of auxin redistribution and the quantification of auxin fluxes. Finally, we also discuss new tools that provide a higher spatial or temporal resolution and our technical needs for future gravitropism studies.
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Affiliation(s)
- M Geisler
- Department of Biology - Plant Biology, University of Fribourg, Fribourg, Switzerland
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338
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Motte H, Vereecke D, Geelen D, Werbrouck S. The molecular path to in vitro shoot regeneration. Biotechnol Adv 2014; 32:107-21. [DOI: 10.1016/j.biotechadv.2013.12.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 11/20/2013] [Accepted: 12/08/2013] [Indexed: 10/25/2022]
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339
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Paque S, Mouille G, Grandont L, Alabadí D, Gaertner C, Goyallon A, Muller P, Primard-Brisset C, Sormani R, Blázquez MA, Perrot-Rechenmann C. AUXIN BINDING PROTEIN1 links cell wall remodeling, auxin signaling, and cell expansion in arabidopsis. THE PLANT CELL 2014; 26:280-95. [PMID: 24424095 PMCID: PMC3963575 DOI: 10.1105/tpc.113.120048] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Cell expansion is an increase in cell size and thus plays an essential role in plant growth and development. Phytohormones and the primary plant cell wall play major roles in the complex process of cell expansion. In shoot tissues, cell expansion requires the auxin receptor AUXIN BINDING PROTEIN1 (ABP1), but the mechanism by which ABP1 affects expansion remains unknown. We analyzed the effect of functional inactivation of ABP1 on transcriptomic changes in dark-grown hypocotyls and investigated the consequences of gene expression on cell wall composition and cell expansion. Molecular and genetic evidence indicates that ABP1 affects the expression of a broad range of cell wall-related genes, especially cell wall remodeling genes, mainly via an SCF(TIR/AFB)-dependent pathway. ABP1 also functions in the modulation of hemicellulose xyloglucan structure. Furthermore, fucosidase-mediated defucosylation of xyloglucan, but not biosynthesis of nonfucosylated xyloglucan, rescued dark-grown hypocotyl lengthening of ABP1 knockdown seedlings. In muro remodeling of xyloglucan side chains via an ABP1-dependent pathway appears to be of critical importance for temporal and spatial control of cell expansion.
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Affiliation(s)
- Sébastien Paque
- Institut des Sciences du Végétal, UPR2355, CNRS, Saclay Plant Sciences, 91198 Gif sur Yvette Cedex, France
| | - Grégory Mouille
- Institut Jean-Pierre Bourgin, Saclay Plant Sciences, INRA Centre de Versailles-Grignon, 78026 Versailles Cedex, France
| | - Laurie Grandont
- Institut des Sciences du Végétal, UPR2355, CNRS, Saclay Plant Sciences, 91198 Gif sur Yvette Cedex, France
| | - David Alabadí
- Instituto de Biología Molecular y Celular de Planta, Consejo Superior de Investigaciones Científicas, Universitat Politécnica de Valencia, 46022 Valencia, Spain
| | - Cyril Gaertner
- Institut Jean-Pierre Bourgin, Saclay Plant Sciences, INRA Centre de Versailles-Grignon, 78026 Versailles Cedex, France
| | - Arnaud Goyallon
- Institut Jean-Pierre Bourgin, Saclay Plant Sciences, INRA Centre de Versailles-Grignon, 78026 Versailles Cedex, France
| | - Philippe Muller
- Institut des Sciences du Végétal, UPR2355, CNRS, Saclay Plant Sciences, 91198 Gif sur Yvette Cedex, France
| | - Catherine Primard-Brisset
- Institut des Sciences du Végétal, UPR2355, CNRS, Saclay Plant Sciences, 91198 Gif sur Yvette Cedex, France
| | - Rodnay Sormani
- Institut Jean-Pierre Bourgin, Saclay Plant Sciences, INRA Centre de Versailles-Grignon, 78026 Versailles Cedex, France
| | - Miguel A. Blázquez
- Instituto de Biología Molecular y Celular de Planta, Consejo Superior de Investigaciones Científicas, Universitat Politécnica de Valencia, 46022 Valencia, Spain
| | - Catherine Perrot-Rechenmann
- Institut des Sciences du Végétal, UPR2355, CNRS, Saclay Plant Sciences, 91198 Gif sur Yvette Cedex, France
- Address correspondence to
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340
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Clark NM, de Luis Balaguer MA, Sozzani R. Experimental data and computational modeling link auxin gradient and development in the Arabidopsis root. FRONTIERS IN PLANT SCIENCE 2014; 5:328. [PMID: 25071810 PMCID: PMC4083358 DOI: 10.3389/fpls.2014.00328] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 06/23/2014] [Indexed: 05/04/2023]
Abstract
The presence of an auxin gradient in the Arabidopsis root is crucial for proper root development and importantly, for stem cell niche (SCN) maintenance. Subsequently, developmental pathways in the root SCN regulate the formation of the auxin gradient. Combinations of experimental data and computational modeling enable the identification of pathways involved in establishing and maintaining the auxin gradient. We describe how the predictive power of these computational models is used to find how genes and their interactions tightly control the formation of an auxin maximum in the SCN. In addition, we highlight known connections between signaling pathways involving auxin and controlling patterning and development in Arabidopsis.
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Affiliation(s)
| | | | - Rosangela Sozzani
- *Correspondence: Rosangela Sozzani, Department of Plant and Microbial Biology, North Carolina State University, 2577 Thomas Hall, P. O. Box 7612, Raleigh, NC 27695, USA e-mail:
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341
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Liu J, Rowe J, Lindsey K. Hormonal crosstalk for root development: a combined experimental and modeling perspective. FRONTIERS IN PLANT SCIENCE 2014; 5:116. [PMID: 24734037 PMCID: PMC3975122 DOI: 10.3389/fpls.2014.00116] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 03/11/2014] [Indexed: 05/18/2023]
Abstract
Plants are sessile organisms and therefore they must adapt their growth and architecture to a changing environment. Understanding how hormones and genes interact to coordinate plant growth in a changing environment is a major challenge in developmental biology. Although a localized auxin concentration maximum in the root tip is important for root development, auxin concentration cannot change independently of multiple interacting hormones and genes. In this review, we discuss the experimental evidence showing that the POLARIS peptide of Arabidopsis plays an important role in hormonal crosstalk and root growth, and review the crosstalk between auxin and other hormones for root growth with and without osmotic stress. Moreover, we discuss that experimental evidence showing that, in root development, hormones and the associated regulatory and target genes form a network, in which relevant genes regulate hormone activities and hormones regulate gene expression. We further discuss how it is increasingly evident that mathematical modeling is a valuable tool for studying hormonal crosstalk. Therefore, a combined experimental and modeling study on hormonal crosstalk is important for elucidating the complexity of root development.
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342
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Gibbs DJ, Coates JC. AtMYB93 is an endodermis-specific transcriptional regulator of lateral root development in arabidopsis. PLANT SIGNALING & BEHAVIOR 2014; 9:e970406. [PMID: 25482809 PMCID: PMC4622915 DOI: 10.4161/15592316.2014.970406] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Plant root systems are critical for survival, acting as the primary interface for nutrient and water acquisition, as well as anchoring the plant to the ground. As plants grow, their root systems become more elaborate, which is largely mediated by the formation of root branches, or lateral roots. Lateral roots initiate deep within the root in the pericycle cell layer, and their development is controlled by a wide range of internal signaling factors and environmental cues, as well as mechanical feedback from the surrounding cells. The endodermal cell layer, which overlies the pericycle, has emerged as an important tissue regulating LR initiation and formation. We recently identified the AtMYB93 transcription factor as a negative regulator of lateral root development in Arabidopsis. Interestingly, AtMYB93 expression is highly restricted to the few endodermal cells overlying developing lateral root primordia, suggesting that this transcriptional regulator might play a key role in mediating the effect of the endodermis on lateral root development. Here we discuss our recent findings in the wider context of root system development - with a particular focus on the role of the endodermis - and propose several potential models to explain AtMYB93 function during lateral root organogenesis.
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Affiliation(s)
- Daniel J Gibbs
- School of Biosciences; University of Birmingham; Edgbaston, UK
| | - Juliet C Coates
- School of Biosciences; University of Birmingham; Edgbaston, UK
- Correspondence to: Juliet C Coates;
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343
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Nawrath C, Schreiber L, Franke RB, Geldner N, Reina-Pinto JJ, Kunst L. Apoplastic diffusion barriers in Arabidopsis. THE ARABIDOPSIS BOOK 2013; 11:e0167. [PMID: 24465172 PMCID: PMC3894908 DOI: 10.1199/tab.0167] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
During the development of Arabidopsis and other land plants, diffusion barriers are formed in the apoplast of specialized tissues within a variety of plant organs. While the cuticle of the epidermis is the primary diffusion barrier in the shoot, the Casparian strips and suberin lamellae of the endodermis and the periderm represent the diffusion barriers in the root. Different classes of molecules contribute to the formation of extracellular diffusion barriers in an organ- and tissue-specific manner. Cutin and wax are the major components of the cuticle, lignin forms the early Casparian strip, and suberin is deposited in the stage II endodermis and the periderm. The current status of our understanding of the relationships between the chemical structure, ultrastructure and physiological functions of plant diffusion barriers is discussed. Specific aspects of the synthesis of diffusion barrier components and protocols that can be used for the assessment of barrier function and important barrier properties are also presented.
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Affiliation(s)
- Christiane Nawrath
- University of Lausanne, Department of Plant Molecular Biology, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Lukas Schreiber
- University of Bonn, Department of Ecophysiology of Plants, Institute of Cellular and Molecular Botany (IZMB), Kirschallee 1, D-53115 Bonn, Germany
| | - Rochus Benni Franke
- University of Bonn, Department of Ecophysiology of Plants, Institute of Cellular and Molecular Botany (IZMB), Kirschallee 1, D-53115 Bonn, Germany
| | - Niko Geldner
- University of Lausanne, Department of Plant Molecular Biology, Biophore Building, CH-1015 Lausanne, Switzerland
| | - José J. Reina-Pinto
- Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’ (IHSM-UMA-CSIC), Department of Plant Breeding, Estación Experimental ‘La Mayora’. 29750 Algarrobo-Costa. Málaga. Spain
| | - Ljerka Kunst
- University of British Columbia, Department of Botany, Vancouver, B.C. V6T 1Z4, Canada
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344
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Cuesta C, Wabnik K, Benková E. Systems approaches to study root architecture dynamics. FRONTIERS IN PLANT SCIENCE 2013; 4:537. [PMID: 24421783 PMCID: PMC3872734 DOI: 10.3389/fpls.2013.00537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 12/11/2013] [Indexed: 05/05/2023]
Abstract
The plant root system is essential for providing anchorage to the soil, supplying minerals and water, and synthesizing metabolites. It is a dynamic organ modulated by external cues such as environmental signals, water and nutrients availability, salinity and others. Lateral roots (LRs) are initiated from the primary root post-embryonically, after which they progress through discrete developmental stages which can be independently controlled, providing a high level of plasticity during root system formation. Within this review, main contributions are presented, from the classical forward genetic screens to the more recent high-throughput approaches, combined with computer model predictions, dissecting how LRs and thereby root system architecture is established and developed.
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Affiliation(s)
- Candela Cuesta
- Institute of Science and Technology AustriaKlosterneuburg, Austria
| | - Krzysztof Wabnik
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB) and Department of Plant Biotechnology and Genetics, Ghent UniversityTechnologiepark, Gent, Belgium
| | - Eva Benková
- Institute of Science and Technology AustriaKlosterneuburg, Austria
- Mendel Centre for Plant Genomics and Proteomics, Masaryk UniversityBrno, Czech Republic
- *Correspondence: Eva Benková, Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria e-mail:
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345
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Simon S, Kubeš M, Baster P, Robert S, Dobrev PI, Friml J, Petrášek J, Zažímalová E. Defining the selectivity of processes along the auxin response chain: a study using auxin analogues. THE NEW PHYTOLOGIST 2013; 200:1034-48. [PMID: 23914741 DOI: 10.1111/nph.12437] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 06/25/2013] [Indexed: 05/08/2023]
Abstract
The mode of action of auxin is based on its non-uniform distribution within tissues and organs. Despite the wide use of several auxin analogues in research and agriculture, little is known about the specificity of different auxin-related transport and signalling processes towards these compounds. Using seedlings of Arabidopsis thaliana and suspension-cultured cells of Nicotiana tabacum (BY-2), the physiological activity of several auxin analogues was investigated, together with their capacity to induce auxin-dependent gene expression, to inhibit endocytosis and to be transported across the plasma membrane. This study shows that the specificity criteria for different auxin-related processes vary widely. Notably, the special behaviour of some synthetic auxin analogues suggests that they might be useful tools in investigations of the molecular mechanism of auxin action. Thus, due to their differential stimulatory effects on DR5 expression, indole-3-propionic (IPA) and 2,4,5-trichlorophenoxy acetic (2,4,5-T) acids can serve in studies of TRANSPORT INHIBITOR RESPONSE 1/AUXIN SIGNALLING F-BOX (TIR1/AFB)-mediated auxin signalling, and 5-fluoroindole-3-acetic acid (5-F-IAA) can help to discriminate between transcriptional and non-transcriptional pathways of auxin signalling. The results demonstrate that the major determinants for the auxin-like physiological potential of a particular compound are very complex and involve its chemical and metabolic stability, its ability to distribute in tissues in a polar manner and its activity towards auxin signalling machinery.
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Affiliation(s)
- Sibu Simon
- Institute of Experimental Botany, The Academy of Sciences of the Czech Republic, Rozvojová 263, 16502, Prague 6, Czech Republic; Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and Genetics, Ghent University, 9052, Ghent, Belgium; Developmental and Cell Physiology of Plants, Institute of Science and Technology (IST Austria), 3400, Klosterneuburg, Austria
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346
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Szymanowska-Pułka J. Form matters: morphological aspects of lateral root development. ANNALS OF BOTANY 2013; 112:1643-54. [PMID: 24190952 PMCID: PMC3838556 DOI: 10.1093/aob/mct231] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Accepted: 08/13/2013] [Indexed: 05/06/2023]
Abstract
BACKGROUND The crucial role of roots in plant nutrition, and consequently in plant productivity, is a strong motivation to study the growth and functioning of various aspects of the root system. Numerous studies on lateral roots, as a major determinant of the root system architecture, mostly focus on the physiological and molecular bases of developmental processes. Unfortunately, little attention is paid either to the morphological changes accompanying the formation of a lateral root or to morphological defects occurring in lateral root primordia. The latter are observed in some mutants and occasionally in wild-type plants, but may also result from application of external factors. SCOPE AND CONCLUSIONS In this review various morphological aspects of lateral branching in roots are analysed. Morphological events occurring during the formation of a typical lateral root are described. This process involves dramatic changes in the geometry of the developing organ that at early stages are associated with oblique cell divisions, leading to breaking of the symmetry of the cell pattern. Several types of defects in the morphology of primordia are indicated and described. Computer simulations show that some of these defects may result from an unstable field of growth rates. Significant changes in both primary and lateral root morphology may also be a consequence of various mutations, some of which are auxin-related. Examples reported in the literature are considered. Finally, lateral root formation is discussed in terms of mechanics. In this approach the primordium is considered as a physical object undergoing deformation and is characterized by specific mechanical properties.
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347
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Kazan K. Auxin and the integration of environmental signals into plant root development. ANNALS OF BOTANY 2013; 112:1655-65. [PMID: 24136877 PMCID: PMC3838554 DOI: 10.1093/aob/mct229] [Citation(s) in RCA: 188] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 08/12/2013] [Indexed: 05/18/2023]
Abstract
BACKGROUND Auxin is a versatile plant hormone with important roles in many essential physiological processes. In recent years, significant progress has been made towards understanding the roles of this hormone in plant growth and development. Recent evidence also points to a less well-known but equally important role for auxin as a mediator of environmental adaptation in plants. SCOPE This review briefly discusses recent findings on how plants utilize auxin signalling and transport to modify their root system architecture when responding to diverse biotic and abiotic rhizosphere signals, including macro- and micro-nutrient starvation, cold and water stress, soil acidity, pathogenic and beneficial microbes, nematodes and neighbouring plants. Stress-responsive transcription factors and microRNAs that modulate auxin- and environment-mediated root development are also briefly highlighted. CONCLUSIONS The auxin pathway constitutes an essential component of the plant's biotic and abiotic stress tolerance mechanisms. Further understanding of the specific roles that auxin plays in environmental adaptation can ultimately lead to the development of crops better adapted to stressful environments.
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Affiliation(s)
- Kemal Kazan
- Commonwealth Scientific and Industrial Organization (CSIRO) Plant Industry, Queensland Bioscience Precinct (QBP), Brisbane, Queensland 4067, Australia
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348
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Jansen L, Hollunder J, Roberts I, Forestan C, Fonteyne P, Van Quickenborne C, Zhen RG, McKersie B, Parizot B, Beeckman T. Comparative transcriptomics as a tool for the identification of root branching genes in maize. PLANT BIOTECHNOLOGY JOURNAL 2013; 11:1092-102. [PMID: 23941360 DOI: 10.1111/pbi.12104] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 07/09/2013] [Indexed: 05/09/2023]
Abstract
The root system is fundamental for plant development, is crucial for overall plant growth and is recently being recognized as the key for future crop productivity improvement. A major determinant of root system architecture is the initiation of lateral roots. While knowledge of the genetic and molecular mechanisms regulating lateral root initiation has mainly been achieved in the dicotyledonous plant Arabidopsis thaliana, only scarce data are available for major crop species, generally monocotyledonous plants. The existence of both similarities and differences at the morphological and anatomical level between plant species from both clades raises the question whether regulation of lateral root initiation may or may not be conserved through evolution. Here, we performed a targeted genome-wide transcriptome analysis during lateral root initiation both in primary and in adventitious roots of Zea mays and found evidence for the existence of common transcriptional regulation. Further, based on a comparative analysis with Arabidopsis transcriptome data, a core of genes putatively conserved across angiosperms could be identified. Therefore, it is plausible that common regulatory mechanisms for lateral root initiation are at play in maize and Arabidopsis, a finding that might encourage the extrapolation of knowledge obtained in Arabidopsis to crop species at the level of root system architecture.
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Affiliation(s)
- Leentje Jansen
- Integrative Plant Biology division, Department of Plant Systems Biology, VIB, Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
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349
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Peng Z, Zhang C, Zhang Y, Hu T, Mu S, Li X, Gao J. Transcriptome sequencing and analysis of the fast growing shoots of moso bamboo (Phyllostachys edulis). PLoS One 2013; 8:e78944. [PMID: 24244391 PMCID: PMC3820679 DOI: 10.1371/journal.pone.0078944] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 09/17/2013] [Indexed: 01/23/2023] Open
Abstract
Background The moso bamboo, a large woody bamboo with the highest ecological, economic, and cultural value of all bamboos, has one of the highest growth speeds in the world. Genetic research into moso bamboo has been scarce, partly because of the lack of previous genomic resources. In the present study, for the first time, we performed de novo transcriptome sequencing and mapped to the moso bamboo genomic resources (reference genome and genes) to produce a comprehensive dataset for the fast growing shoots of moso bamboo. Results The fast growing shoots mixed with six different heights and culms after leaf expansion of moso bamboo transcriptome were sequenced using the Illumina HiSeq™ 2000 sequencing platform, respectively. More than 80 million reads including 65,045,670 and 68,431,884 clean reads were produced in the two libraries. More than 81% of the reads were matched to the reference genome, and nearly 50% of the reads were matched to the reference genes. The genes with log 2 ratio > 2 or < −2 (P<0.001) were characterized as the most differentially expressed genes. 6,076 up-regulated and 4,613 down-regulated genes were classified into functional categories. Candidate genes which mainly involved transcript factors, plant hormones, cell cycle regulation, cell wall metabolism and cell morphogenesis genes were further analyzed and they may form a network that regulates the fast growth of moso bamboo shoots. Conclusion Firstly, our data provides the most comprehensive transcriptomic resource for moso bamboo to date. Candidate genes have been identified and they are potentially involved in the growth and development of moso bamboo. The results give a better insight into the mechanisms of moso bamboo shoots rapid growth and provide gene resources for improving plant growth.
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Affiliation(s)
- Zhenhua Peng
- International Center for Bamboo and Rattan, Key Laboratory of Bamboo and Rattan Science and Technology, State Forestry Administration, Beijing, People's Republic of China
| | - Chunling Zhang
- International Center for Bamboo and Rattan, Key Laboratory of Bamboo and Rattan Science and Technology, State Forestry Administration, Beijing, People's Republic of China
| | - Ying Zhang
- International Center for Bamboo and Rattan, Key Laboratory of Bamboo and Rattan Science and Technology, State Forestry Administration, Beijing, People's Republic of China
| | - Tao Hu
- International Center for Bamboo and Rattan, Key Laboratory of Bamboo and Rattan Science and Technology, State Forestry Administration, Beijing, People's Republic of China
| | - Shaohua Mu
- International Center for Bamboo and Rattan, Key Laboratory of Bamboo and Rattan Science and Technology, State Forestry Administration, Beijing, People's Republic of China
| | - Xueping Li
- International Center for Bamboo and Rattan, Key Laboratory of Bamboo and Rattan Science and Technology, State Forestry Administration, Beijing, People's Republic of China
| | - Jian Gao
- International Center for Bamboo and Rattan, Key Laboratory of Bamboo and Rattan Science and Technology, State Forestry Administration, Beijing, People's Republic of China
- * E-mail:
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Péret B, Middleton AM, French AP, Larrieu A, Bishopp A, Njo M, Wells DM, Porco S, Mellor N, Band LR, Casimiro I, Kleine-Vehn J, Vanneste S, Sairanen I, Mallet R, Sandberg G, Ljung K, Beeckman T, Benkova E, Friml J, Kramer E, King JR, De Smet I, Pridmore T, Owen M, Bennett MJ. Sequential induction of auxin efflux and influx carriers regulates lateral root emergence. Mol Syst Biol 2013; 9:699. [PMID: 24150423 PMCID: PMC3817398 DOI: 10.1038/msb.2013.43] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 08/06/2013] [Indexed: 12/15/2022] Open
Abstract
Emergence of a new lateral root primordium through the outer layers of the parental root requires the sequential auxin-mediated induction of two auxin transporters. This positive feedback regulatory loop coordinates patterned gene expression in outer tissues. ![]()
The emergence of lateral roots through several tissues requires the precise regulation of gene expression in overlaying cells to trigger cell separation. Auxin derived from new lateral root primordia induces a positive feedback loop in the outer tissues by promoting the expression of the auxin influx transporter LAX3. A mathematical model based on realistic 3D geometries predicted the involvement of an auxin efflux carrier that was later identified to be PIN3. The model also revealed that PIN3 must be expressed before LAX3 to ensure a ‘robust' pattern of LAX3 induction in just two overlaying cortical cell files, thereby delimiting cell separation.
In Arabidopsis, lateral roots originate from pericycle cells deep within the primary root. New lateral root primordia (LRP) have to emerge through several overlaying tissues. Here, we report that auxin produced in new LRP is transported towards the outer tissues where it triggers cell separation by inducing both the auxin influx carrier LAX3 and cell-wall enzymes. LAX3 is expressed in just two cell files overlaying new LRP. To understand how this striking pattern of LAX3 expression is regulated, we developed a mathematical model that captures the network regulating its expression and auxin transport within realistic three-dimensional cell and tissue geometries. Our model revealed that, for the LAX3 spatial expression to be robust to natural variations in root tissue geometry, an efflux carrier is required—later identified to be PIN3. To prevent LAX3 from being transiently expressed in multiple cell files, PIN3 and LAX3 must be induced consecutively, which we later demonstrated to be the case. Our study exemplifies how mathematical models can be used to direct experiments to elucidate complex developmental processes.
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Affiliation(s)
- Benjamin Péret
- 1] Centre for Plant Integrative Biology, University of Nottingham, Loughborough, UK [2] Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough, UK [3] Unité Mixte de Recherche 7265, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, Aix-Marseille Université, Laboratoire de Biologie du Développement des Plantes, Saint-Paul-lez-Durance, France
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