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Abstract
The desiccated, quiescent state of seeds confers extended survival of the embryonic plant. However, accumulation of striking levels of genome damage in quiescence impairs germination and threatens plant survival. The mechanisms by which seeds mitigate this damage remain unclear. Here, we reveal that imbibed Arabidopsis seeds display high resistance to DNA damage, which is lost as seeds advance to germination, coincident with increasing cell cycle activity. In contrast to seedlings, we show that seeds minimize the impact of DNA damage by reducing meristem disruption and delaying SOG1-dependent programmed cell death. This promotes root growth early postgermination. In response to naturally accumulated DNA damage in aging seeds, SOG1 activates cell death postgermination. SOG1 activities are also important for promoting successful seedling establishment. These distinct cellular responses of seeds and seedlings are reflected by different DNA damage transcriptional profiles. Comparative analysis of DNA repair mutants identifies roles of the major genome maintenance pathways in germination but that the repair of cytotoxic chromosomal breaks is the most important for seed longevity. Collectively, these results indicate that high levels of DNA damage incurred in seeds are countered by low cell cycle activity, cell cycle checkpoints, and DNA repair, promoting successful seedling establishment. Our findings reveal insight into both the physiological significance of plant DNA damage responses and the mechanisms which maintain seed longevity, important for survival of plant populations in the natural environment and sustainable crop production under changing climates.
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Rivas MÁ, Friero I, Alarcón MV, Salguero J. Auxin-Cytokinin Balance Shapes Maize Root Architecture by Controlling Primary Root Elongation and Lateral Root Development. FRONTIERS IN PLANT SCIENCE 2022; 13:836592. [PMID: 35548278 PMCID: PMC9081935 DOI: 10.3389/fpls.2022.836592] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 03/07/2022] [Indexed: 05/12/2023]
Abstract
The root system is responsible for water and nutrients uptake from the soil, and therefore, its extension is basic for an efficient acquisition. The maize root system is formed by different types of roots, and the lateral root branching substantially increases the surface for nutrient uptake. Therefore, the regulation of lateral root formation is fundamental in the development of root functions. Root architecture is basically controlled by auxin and cytokinins, which antagonize in the formation of lateral roots (LR) along the primary root axis, with auxin, a stimulator, and cytokinins inhibitors of LR development. This interaction has been analyzed in several zones along the primary root where LRs in different developmental stages were located. The root has been divided into several zones, such as meristem, elongation zone, and mature zone, according to the developmental processes occurring in each one. As Arabidopsis root elongated more slowly than maize root, these zones are shorter, and its delimitation is more difficult. However, these zones have previously been delimitated clearly in maize, and therefore, they analyze the effect of exogenous hormones in several LR developmental stages. The inhibitory effect of cytokinin on lateral root formation was observed in already elongated primary root zones in which initial events to form new lateral roots are taking place. Contrarily, auxin increased LR formation in the primary root segments elongated in the presence of the hormone. The inhibitory effect of cytokinin was reversed by auxin in a concentration-dependent manner when both hormones were combined. However, auxin is unable to recover LR development in primary root zones that have been previously elongated only in the presence of cytokinin. This antagonistic auxin-cytokinin effect on LR development depended on the balance between both hormones, which controls the root system architecture and determines the formation of LR during the process of initiation.
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Affiliation(s)
- M. Ángeles Rivas
- Departamento de Biología Vegetal, Ecología y Ciencias de la Tierra, Universidad de Extremadura, Badajoz, Spain
| | - Iván Friero
- Departamento de Biología Vegetal, Ecología y Ciencias de la Tierra, Universidad de Extremadura, Badajoz, Spain
| | - M. Victoria Alarcón
- Departamento de Hortofruticultura, Instituto de Investigaciones Agrarias “La Orden-Valdesequera”, Centro de Investigaciones Científicas y Tecnológicas de Extremadura (CICYTEX), Junta de Extremadura, Badajoz, Spain
| | - Julio Salguero
- Departamento de Biología Vegetal, Ecología y Ciencias de la Tierra, Universidad de Extremadura, Badajoz, Spain
- *Correspondence: Julio Salguero,
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Takahashi N, Inagaki S, Nishimura K, Sakakibara H, Antoniadi I, Karady M, Ljung K, Umeda M. Alterations in hormonal signals spatially coordinate distinct responses to DNA double-strand breaks in Arabidopsis roots. SCIENCE ADVANCES 2021; 7:7/25/eabg0993. [PMID: 34134976 PMCID: PMC8208723 DOI: 10.1126/sciadv.abg0993] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 04/28/2021] [Indexed: 06/12/2023]
Abstract
Plants have a high ability to cope with changing environments and grow continuously throughout life. However, the mechanisms by which plants strike a balance between stress response and organ growth remain elusive. Here, we found that DNA double-strand breaks enhance the accumulation of cytokinin hormones through the DNA damage signaling pathway in the Arabidopsis root tip. Our data showed that activation of cytokinin signaling suppresses the expression of some of the PIN-FORMED genes that encode efflux carriers of another hormone, auxin, thereby decreasing the auxin signals in the root tip and causing cell cycle arrest at G2 phase and stem cell death. Elevated cytokinin signaling also promotes an early transition from cell division to endoreplication in the basal part of the root apex. We propose that plant hormones spatially coordinate differential DNA damage responses, thereby maintaining genome integrity and minimizing cell death to ensure continuous root growth.
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Affiliation(s)
- Naoki Takahashi
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara 630-0192, Japan
| | - Soichi Inagaki
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara 630-0192, Japan
| | - Kohei Nishimura
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara 630-0192, Japan
| | - Hitoshi Sakakibara
- Plant Productivity Systems Research Group, RIKEN Center for Sustainable Resource Science, Suehiro 1-7-22, Tsurumi, Yokohama 230-0045, Japan
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Ioanna Antoniadi
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 90183 Umeå, Sweden
| | - Michal Karady
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 90183 Umeå, Sweden
| | - Karin Ljung
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 90183 Umeå, Sweden
| | - Masaaki Umeda
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara 630-0192, Japan.
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Convergence and Divergence of Sugar and Cytokinin Signaling in Plant Development. Int J Mol Sci 2021; 22:ijms22031282. [PMID: 33525430 PMCID: PMC7865218 DOI: 10.3390/ijms22031282] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/19/2021] [Accepted: 01/24/2021] [Indexed: 02/06/2023] Open
Abstract
Plants adjust their growth and development through a sophisticated regulatory system integrating endogenous and exogenous cues. Many of them rely on intricate crosstalk between nutrients and hormones, an effective way of coupling nutritional and developmental information and ensuring plant survival. Sugars in their different forms such as sucrose, glucose, fructose and trehalose-6-P and the hormone family of cytokinins (CKs) are major regulators of the shoot and root functioning throughout the plant life cycle. While their individual roles have been extensively investigated, their combined effects have unexpectedly received little attention, resulting in many gaps in current knowledge. The present review provides an overview of the relationship between sugars and CKs signaling in the main developmental transition during the plant lifecycle, including seed development, germination, seedling establishment, root and shoot branching, leaf senescence, and flowering. These new insights highlight the diversity and the complexity of the crosstalk between sugars and CKs and raise several questions that will open onto further investigations of these regulation networks orchestrating plant growth and development.
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Tanaka H, Takeda K, Imai A. Polyamines alleviate the inhibitory effect of the DNA cross-linking agent mitomycin C on root growth. PLANT SIGNALING & BEHAVIOR 2019; 14:1659687. [PMID: 31446839 PMCID: PMC6804717 DOI: 10.1080/15592324.2019.1659687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/15/2019] [Accepted: 08/16/2019] [Indexed: 06/10/2023]
Abstract
Polyamines (putrescine, spermidine and spermine) are ubiquitously present in various types of cells of living organisms. They are involved in a variety of cellular processes, including cell proliferation and cell differentiation, and are required for abiotic stress tolerances in plants. However, it is still not understood whether polyamines are involved in the plant growth inhibition caused by DNA-damaging agents. In this study, we examined the effects of polyamines on the inhibition of plant root growth and gene expression in Arabidopsis thaliana treated with mitomycin C (MMC), a genotoxic agent that induces DNA interstrand crosslinks. We found that polyamines alleviated the inhibitory effect caused by MMC on root growth. In addition, we also found that polyamines alleviated the increased expression of AtBRCA1 and AtRAD51 genes induced by MMC treatment. Our study provides the first evidence that polyamines contribute to tolerance against plant-growth inhibition caused by a DNA-damaging chemical.
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Affiliation(s)
- Hidenori Tanaka
- Department of Biomedical Engineering, Graduate School of Science and Technology, Hiroshima Institute of Technology, Hiroshima, Japan
| | - Kazuya Takeda
- Department of Food Sciences and Biotechnology, Faculty of Life Sciences, Hiroshima Institute of Technology, Hiroshima, Japan
| | - Akihiro Imai
- Department of Biomedical Engineering, Graduate School of Science and Technology, Hiroshima Institute of Technology, Hiroshima, Japan
- Department of Food Sciences and Biotechnology, Faculty of Life Sciences, Hiroshima Institute of Technology, Hiroshima, Japan
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Araújo S, Pagano A, Dondi D, Lazzaroni S, Pinela E, Macovei A, Balestrazzi A. Metabolic signatures of germination triggered by kinetin in Medicago truncatula. Sci Rep 2019; 9:10466. [PMID: 31320688 PMCID: PMC6639397 DOI: 10.1038/s41598-019-46866-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 07/01/2019] [Indexed: 11/09/2022] Open
Abstract
In the present work, non-targeted metabolomics was used to investigate the seed response to kinetin, a phytohormone with potential roles in seed germination, still poorly explored. The aim of this study was to elucidate the metabolic signatures of germination triggered by kinetin and explore changes in metabolome to identify novel vigor/stress hallmarks in Medicago truncatula. Exposure to 0.5 mM kinetin accelerated seed germination but impaired seedling growth. Metabolite composition was investigated in seeds imbibed with water or with 0.5 mM kinetin collected at 2 h and 8 h of imbibition, and at the radicle protrusion stage. According to Principal Component Analysis, inositol pentakisphosphate, agmatine, digalactosylglycerol, inositol hexakisphosphate, and oleoylcholine were the metabolites that mostly contributed to the separation between 2 h, 8 h and radicle protrusion stage, irrespective of the treatment applied. Overall, only 27 metabolites showed significant changes in mean relative contents triggered by kinetin, exclusively at the radicle protrusion stage. The observed metabolite depletion might associate with faster germination or regarded as a stress signature. Results from alkaline comet assay, highlighting the occurrence of DNA damage at this stage of germination, are consistent with the hypothesis that prolonged exposure to kinetin induces stress conditions leading to genotoxic injury.
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Affiliation(s)
- Susana Araújo
- Instituto de Tecnologia Química e Biológica António Xavier - Universidade Nova de Lisboa (ITQB-NOVA), Av. da República, 2780-157, Oeiras, Portugal
| | - Andrea Pagano
- Department of Biology and Biotechnology 'L. Spallanzani', via Ferrata 9, 27100, Pavia, Italy
| | - Daniele Dondi
- Department of Chemistry, Viale Taramelli 12, 27100, Pavia, Italy
| | - Simone Lazzaroni
- Department of Chemistry, Viale Taramelli 12, 27100, Pavia, Italy
| | - Eduardo Pinela
- Instituto de Tecnologia Química e Biológica António Xavier - Universidade Nova de Lisboa (ITQB-NOVA), Av. da República, 2780-157, Oeiras, Portugal
| | - Anca Macovei
- Department of Biology and Biotechnology 'L. Spallanzani', via Ferrata 9, 27100, Pavia, Italy
| | - Alma Balestrazzi
- Department of Biology and Biotechnology 'L. Spallanzani', via Ferrata 9, 27100, Pavia, Italy.
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Nisa MU, Huang Y, Benhamed M, Raynaud C. The Plant DNA Damage Response: Signaling Pathways Leading to Growth Inhibition and Putative Role in Response to Stress Conditions. FRONTIERS IN PLANT SCIENCE 2019; 10:653. [PMID: 31164899 PMCID: PMC6534066 DOI: 10.3389/fpls.2019.00653] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/30/2019] [Indexed: 05/02/2023]
Abstract
Maintenance of genome integrity is a key issue for all living organisms. Cells are constantly exposed to DNA damage due to replication or transcription, cellular metabolic activities leading to the production of Reactive Oxygen Species (ROS) or even exposure to DNA damaging agents such as UV light. However, genomes remain extremely stable, thanks to the permanent repair of DNA lesions. One key mechanism contributing to genome stability is the DNA Damage Response (DDR) that activates DNA repair pathways, and in the case of proliferating cells, stops cell division until DNA repair is complete. The signaling mechanisms of the DDR are quite well conserved between organisms including in plants where they have been investigated into detail over the past 20 years. In this review we summarize the acquired knowledge and recent advances regarding the DDR control of cell cycle progression. Studying the plant DDR is particularly interesting because of their mode of development and lifestyle. Indeed, plants develop largely post-embryonically, and form new organs through the activity of meristems in which cells retain the ability to proliferate. In addition, they are sessile organisms that are permanently exposed to adverse conditions that could potentially induce DNA damage in all cell types including meristems. In the second part of the review we discuss the recent findings connecting the plant DDR to responses to biotic and abiotic stresses.
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Du Y, Scheres B. Lateral root formation and the multiple roles of auxin. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:155-167. [PMID: 28992266 DOI: 10.1093/jxb/erx223] [Citation(s) in RCA: 195] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Root systems can display variable architectures that contribute to survival strategies of plants. The model plant Arabidopsis thaliana possesses a tap root system, in which the primary root and lateral roots (LRs) are major architectural determinants. The phytohormone auxin fulfils multiple roles throughout LR development. In this review, we summarize recent advances in our understanding of four aspects of LR formation: (i) LR positioning, which determines the spatial distribution of lateral root primordia (LRP) and LRs along primary roots; (ii) LR initiation, encompassing the activation of nuclear migration in specified lateral root founder cells (LRFCs) up to the first asymmetric cell division; (iii) LR outgrowth, the 'primordium-intrinsic' patterning of de novo organ tissues and a meristem; and (iv) LR emergence, an interaction between LRP and overlaying tissues to allow passage through cell layers. We discuss how auxin signaling, embedded in a changing developmental context, plays important roles in all four phases. In addition, we discuss how rapid progress in gene network identification and analysis, modeling, and four-dimensional imaging techniques have led to an increasingly detailed understanding of the dynamic regulatory networks that control LR development.
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Affiliation(s)
- Yujuan Du
- Plant Developmental Biology Group, Wageningen University Research, the Netherlands
| | - Ben Scheres
- Plant Developmental Biology Group, Wageningen University Research, the Netherlands
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