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Yokawa K, Baluška F. Pectins, ROS homeostasis and UV-B responses in plant roots. PHYTOCHEMISTRY 2015; 112:80-3. [PMID: 25220496 DOI: 10.1016/j.phytochem.2014.08.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/18/2014] [Accepted: 08/15/2014] [Indexed: 05/04/2023]
Abstract
Light from the sun contains far-red, visible and ultra violet (UV) wavelength regions. Almost all plant species have been evolved under the light environment. Interestingly, several photoreceptors, expressing both in shoots and roots, process the light information during the plant life cycle. Surprisingly, Arabidopsis root apices express besides the UVR8 UV-B receptor, also root-specific UV-B sensing proteins RUS1 and RUS2 linked to the polar cell-cell transport of auxin. In this mini-review, we focus on reactive oxygen species (ROS) signaling and possible roles of pectins internalized via endocytic vesicle recycling system in the root-specific UV-B perception and ROS homeostasis.
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Affiliation(s)
- Ken Yokawa
- IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany
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52
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Lehmann S, Serrano M, L'Haridon F, Tjamos SE, Metraux JP. Reactive oxygen species and plant resistance to fungal pathogens. PHYTOCHEMISTRY 2015; 112:54-62. [PMID: 25264341 DOI: 10.1016/j.phytochem.2014.08.027] [Citation(s) in RCA: 154] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 08/18/2014] [Accepted: 08/28/2014] [Indexed: 05/18/2023]
Abstract
Reactive oxygen species (ROS) have been studied for their role in plant development as well as in plant immunity. ROS were consistently observed to accumulate in the plant after the perception of pathogens and microbes and over the years, ROS were postulated to be an integral part of the defence response of the plant. In this article we will focus on recent findings about ROS involved in the interaction of plants with pathogenic fungi. We will describe the ways to detect ROS, their modes of action and their importance in relation to resistance to fungal pathogens. In addition we include some results from works focussing on the fungal interactor and from studies investigating roots during pathogen attack.
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Affiliation(s)
- Silke Lehmann
- Department of Biology, University of Fribourg, 10 chemin du Musée, CH-1700 Fribourg, Switzerland.
| | - Mario Serrano
- Department of Biology, University of Fribourg, 10 chemin du Musée, CH-1700 Fribourg, Switzerland.
| | - Floriane L'Haridon
- Department of Biology, University of Fribourg, 10 chemin du Musée, CH-1700 Fribourg, Switzerland.
| | - Sotirios E Tjamos
- Laboratory of Plant Pathology, Department of Crop Science, Agricultural University of Athens, 75 Iera Odos, 118 55 Athens, Greece.
| | - Jean-Pierre Metraux
- Department of Biology, University of Fribourg, 10 chemin du Musée, CH-1700 Fribourg, Switzerland.
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53
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Mo M, Yokawa K, Wan Y, Baluška F. How and why do root apices sense light under the soil surface? FRONTIERS IN PLANT SCIENCE 2015; 6:775. [PMID: 26442084 PMCID: PMC4585147 DOI: 10.3389/fpls.2015.00775] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 09/10/2015] [Indexed: 05/18/2023]
Abstract
Light can penetrate several centimeters below the soil surface. Growth, development and behavior of plant roots are markedly affected by light despite their underground lifestyle. Early studies provided contrasting information on the spatial and temporal distribution of light-sensing cells in the apical region of root apex and discussed the physiological roles of plant hormones in root responses to light. Recent biological and microscopic advances have improved our understanding of the processes involved in the sensing and transduction of light signals, resulting in subsequent physiological and behavioral responses in growing root apices. Here, we review current knowledge of cellular distributions of photoreceptors and their signal transduction pathways in diverse root tissues and root apex zones. We are discussing also the roles of auxin transporters in roots exposed to light, as well as interactions of light signal perceptions with sensing of other environmental factors relevant to plant roots.
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Affiliation(s)
- Mei Mo
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Ken Yokawa
- Institute of Cellular and Molecular Botany, University of Bonn, Bonn, Germany
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, Japan
| | - Yinglang Wan
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
- *Correspondence: Yinglang Wan, College of Biological Sciences and Biotechnology, Beijing Forestry University, Qinghua East Road No. 35, 100083 Beijing, China, ; František Baluška, Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, D-53115 Bonn, Germany,
| | - František Baluška
- Institute of Cellular and Molecular Botany, University of Bonn, Bonn, Germany
- *Correspondence: Yinglang Wan, College of Biological Sciences and Biotechnology, Beijing Forestry University, Qinghua East Road No. 35, 100083 Beijing, China, ; František Baluška, Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, D-53115 Bonn, Germany,
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54
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Yokawa K, Kagenishi T, Baluška F. UV-B Induced Generation of Reactive Oxygen Species Promotes Formation of BFA-Induced Compartments in Cells of Arabidopsis Root Apices. FRONTIERS IN PLANT SCIENCE 2015; 6:1162. [PMID: 26793199 PMCID: PMC4710705 DOI: 10.3389/fpls.2015.01162] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 12/07/2015] [Indexed: 05/10/2023]
Abstract
UV-B radiation is an important part of the electromagnetic spectrum emitted by the sun. For much of the period of biological evolution organisms have been exposed to UV radiation, and have developed diverse mechanisms to cope with this potential stress factor. Roots are usually shielded from exposure to UV by the surrounding soil, but may nevertheless be exposed to high energy radiation on the soil surface. Due to their high sensitivity to UV-B radiation, plant roots need to respond rapidly in order to minimize exposure on the surface. In addition to root gravitropism, effective light perception by roots has recently been discovered to be essential for triggering negative root phototropism in Arabidopsis. However, it is not fully understood how UV-B affects root growth and phototropism. Here, we report that UV-B induces rapid generation of reactive oxygen species which in turn promotes the formation of BFA-induced compartments in the Arabidopsis root apex. During unilateral UV-B irradiation of roots changes in auxin concentration on the illuminated side have been recorded. In conclusion, UV-B-induced and ROS-mediated stimulation of vesicle recycling promotes root growth and induces negative phototropism.
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Affiliation(s)
- Ken Yokawa
- Institute of Cellular and Molecular Botany, University of Bonn, BonnGermany
- Department of Biological Sciences, Tokyo Metropolitan UniversityTokyo, Japan
| | - Tomoko Kagenishi
- Institute of Cellular and Molecular Botany, University of Bonn, BonnGermany
| | - František Baluška
- Institute of Cellular and Molecular Botany, University of Bonn, BonnGermany
- *Correspondence: František Baluška,
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55
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Yokawa K, Baluška F. C. elegans and Arabidopsis thaliana show similar behavior: ROS induce escape tropisms both in illuminated nematodes and roots. PLANT SIGNALING & BEHAVIOR 2015; 10:e1073870. [PMID: 26517053 PMCID: PMC4883826 DOI: 10.1080/15592324.2015.1073870] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 07/13/2015] [Indexed: 06/05/2023]
Affiliation(s)
- Ken Yokawa
- IZMB; University of Bonn; Bonn, Germany
- Department of Biological Sciences; Tokyo Metropolitan University; Tokyo, Japan
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56
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Yokawa K, Koshiba T, Baluška F. Light-dependent control of redox balance and auxin biosynthesis in plants. PLANT SIGNALING & BEHAVIOR 2014. [PMID: 24926992 PMCID: PMC4205145 DOI: 10.4161/psb.29522] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Auxin, indole-3-acetic acid (IAA), plays a crucial role for morphogenesis, development, growth, and tropisms in many plant species. Auxin biosynthesis is accomplished via specific pathways depending on several enzymes starting from amino acid, tryptophan. Auxin biosynthesis in maize is particularly active at the tip of coleoptile expressing abundant YUCCA (YUC) protein, which is essential for auxin biosynthesis. In vitro experiment demonstrated that precursor of auxin molecule; indole-3-acetaldehyde (IAAld) was generated by illumination of the mixture of tryptophan and flavin in non-enzymatic manner. In addition, we have detected immediate production of reactive oxygen species (ROS) in illuminated Arabidopsis root cells. In this perspective, we are proposing the non-enzymatic regulation of redox homeostasis and auxin biosynthesis throughout the plant body under variable environmental light conditions.
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Affiliation(s)
- Ken Yokawa
- Department of Biological Sciences; Tokyo Metropolitan University; Tokyo, Japan
- IZMB; University of Bonn; Bonn, Germany
- Correspondence to: Ken Yokawa,
| | - Tomokazu Koshiba
- Department of Biological Sciences; Tokyo Metropolitan University; Tokyo, Japan
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57
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Yokawa K, Koshiba T, Baluška F. Light-dependent control of redox balance and auxin biosynthesis in plants. PLANT SIGNALING & BEHAVIOR 2014; 9:e29522. [PMID: 24926992 PMCID: PMC4205145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 06/08/2014] [Indexed: 02/28/2024]
Abstract
Auxin, indole-3-acetic acid (IAA), plays a crucial role for morphogenesis, development, growth, and tropisms in many plant species. Auxin biosynthesis is accomplished via specific pathways depending on several enzymes starting from amino acid, tryptophan. Auxin biosynthesis in maize is particularly active at the tip of coleoptile expressing abundant YUCCA (YUC) protein, which is essential for auxin biosynthesis. In vitro experiment demonstrated that precursor of auxin molecule; indole-3-acetaldehyde (IAAld) was generated by illumination of the mixture of tryptophan and flavin in non-enzymatic manner. In addition, we have detected immediate production of reactive oxygen species (ROS) in illuminated Arabidopsis root cells. In this perspective, we are proposing the non-enzymatic regulation of redox homeostasis and auxin biosynthesis throughout the plant body under variable environmental light conditions.
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Affiliation(s)
- Ken Yokawa
- Department of Biological Sciences; Tokyo Metropolitan University; Tokyo, Japan
- IZMB; University of Bonn; Bonn, Germany
| | - Tomokazu Koshiba
- Department of Biological Sciences; Tokyo Metropolitan University; Tokyo, Japan
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58
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Dinh PTY, Knoblauch M, Elling AA. Nondestructive imaging of plant-parasitic nematode development and host response to nematode pathogenesis. PHYTOPATHOLOGY 2014; 104:497-506. [PMID: 24313744 DOI: 10.1094/phyto-08-13-0240-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The secluded lifestyle of endoparasitic plant nematodes hampers progress toward a comprehensive understanding of plant-nematode interactions. A novel technique that enables nondestructive, long-term observations of a wide range of live nematodes in planta is presented here. As proof of principle, Pratylenchus penetrans, Heterodera schachtii, and Meloidogyne chitwoodi were labeled fluorescently with PKH26 and used to infect Arabidopsis thaliana grown in microscopy rhizosphere chambers. Nematode behavior, development, and morphology were observed for the full duration of each parasite's life cycle by confocal microscopy for up to 27 days after inoculation. PKH26 accumulated in intestinal lipid droplets and had no negative effect on nematode infectivity. This technique enabled visualization of Meloidogyne gall formation, nematode oogenesis, and nematode morphological features, such as the metacorpus, vulva, spicules, and cuticle. Additionally, microscopy rhizosphere chambers were used to characterize plant organelle dynamics during M. chitwoodi infection. Peroxisome abundance strongly increased in early giant cells but showed a marked decrease at later stages of feeding site development, which suggests a modulation of plant peroxisomes by root-knot nematodes during the infection process. Taken together, this technique facilitates studies aimed at deciphering plant-nematode interactions at the cellular and subcellular level and enables unprecedented insights into nematode behavior in planta.
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59
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Iwase J, Furukawa H, Hiramatsu T, Bouteau F, Mancuso S, Tanaka K, Okazaki T, Kawano T. Protection of tobacco cells from oxidative copper toxicity by catalytically active metal-binding DNA oligomers. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:1391-402. [PMID: 24659609 DOI: 10.1093/jxb/eru028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The impact of copper ions on the oxidative and calcium signal transductions, leading to cell death in plant cells, have been documented. Copper induces a series of biological and chemical reactions in plant cells including the oxidative burst reflecting the production of reactive oxygen species and the stimulation of calcium channel opening allowing a transient increase in cytosolic calcium concentrations. These early events, completed within a few minutes after the contact with copper, are known to trigger the development of cell death. The effects of DNA fragments with copper-binding motifs as novel plant cell-protecting agents were assessed using cell suspension cultures of transgenic tobacco (Nicotiana tabacum L., cell line BY-2) expressing the aequorin gene. The addition of GC-rich double-stranded DNA fragments, prior to the addition of copper ions, effectively blocked both the copper-induced calcium influx and cell death. In addition, the DNA-Cu complex examined was shown to possess superoxide-scavenging catalytic activity, suggesting that DNA-mediated protection of the cells from copper toxicity is due to the removal of superoxide. Lastly, a possible mechanism of DNA-Cu interaction and future applications of these DNA fragments in the protection of plant roots from metal toxicity or in aid of phyto-remediation processes are discussed.
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Affiliation(s)
- Junichiro Iwase
- Graduate School of Environmental Engineering, The University of Kitakyushu, Kitakyushu, Japan
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60
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Yokawa K, Fasano R, Kagenishi T, Baluška F. Light as stress factor to plant roots - case of root halotropism. FRONTIERS IN PLANT SCIENCE 2014; 5:718. [PMID: 25566292 PMCID: PMC4264407 DOI: 10.3389/fpls.2014.00718] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 11/28/2014] [Indexed: 05/04/2023]
Abstract
Despite growing underground, largely in darkness, roots emerge to be very sensitive to light. Recently, several important papers have been published which reveal that plant roots not only express all known light receptors but also that their growth, physiology and adaptive stress responses are light-sensitive. In Arabidopsis, illumination of roots speeds-up root growth via reactive oxygen species-mediated and F-actin dependent process. On the other hand, keeping Arabidopsis roots in darkness alters F-actin distribution, polar localization of PIN proteins as well as polar transport of auxin. Several signaling components activated by phytohormones are overlapping with light-related signaling cascade. We demonstrated that the sensitivity of roots to salinity is altered in the light-grown Arabidopsis roots. Particularly, light-exposed roots are less effective in their salt-avoidance behavior known as root halotropism. Here we discuss these new aspects of light-mediated root behavior from cellular, physiological and evolutionary perspectives.
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Affiliation(s)
- Ken Yokawa
- Department of Plant Cell Biology, Institute of Cellular and Molecular Botany, University of BonnBonn, Germany
- Department of Biological Sciences, Tokyo Metropolitan UniversityTokyo, Japan
| | - Rossella Fasano
- Department of Pharmacy, University of SalernoFisciano, Italy
| | - Tomoko Kagenishi
- Department of Plant Cell Biology, Institute of Cellular and Molecular Botany, University of BonnBonn, Germany
| | - František Baluška
- Department of Plant Cell Biology, Institute of Cellular and Molecular Botany, University of BonnBonn, Germany
- *Correspondence: František Baluška, Department of Plant Cell Biology, Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115 Bonn, Germany e-mail:
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61
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Baluška F, Mancuso S. Root apex transition zone as oscillatory zone. FRONTIERS IN PLANT SCIENCE 2013; 4:354. [PMID: 24106493 PMCID: PMC3788588 DOI: 10.3389/fpls.2013.00354] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 08/22/2013] [Indexed: 05/17/2023]
Abstract
Root apex of higher plants shows very high sensitivity to environmental stimuli. The root cap acts as the most prominent plant sensory organ; sensing diverse physical parameters such as gravity, light, humidity, oxygen, and critical inorganic nutrients. However, the motoric responses to these stimuli are accomplished in the elongation region. This spatial discrepancy was solved when we have discovered and characterized the transition zone which is interpolated between the apical meristem and the subapical elongation zone. Cells of this zone are very active in the cytoskeletal rearrangements, endocytosis and endocytic vesicle recycling, as well as in electric activities. Here we discuss the oscillatory nature of the transition zone which, together with several other features of this zone, suggest that it acts as some kind of command center. In accordance with the early proposal of Charles and Francis Darwin, cells of this root zone receive sensory information from the root cap and instruct the motoric responses of cells in the elongation zone.
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Affiliation(s)
- František Baluška
- Institute of Cellular and Molecular Botany, Department of Plant Cell Biology, University of BonnBonn, Germany
| | - Stefano Mancuso
- LINV – DiSPAA, Department of Agri-Food and Environmental Science, University of FlorenceSesto Fiorentino, Italy
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62
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Zou N, Li B, Chen H, Su Y, Kronzucker HJ, Xiong L, Baluška F, Shi W. GSA-1/ARG1 protects root gravitropism in Arabidopsis under ammonium stress. THE NEW PHYTOLOGIST 2013; 200:97-111. [PMID: 23782229 DOI: 10.1111/nph.12365] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 05/11/2013] [Indexed: 05/22/2023]
Abstract
Gravitropism plays a critical role in plant growth and development, plant stability and acclimation to changes in water and nutrient availability. Ammonium (NH4(+)) is well known to have profound effects on root growth, but its impacts on gravitropism are poorly understood. To determine which genes are essential for the maintenance of root gravitropism under NH4(+) stress, we isolated and identified an NH4 (+)-sensitive mutant, gsa-1 (gravitropism sensitive to ammonium-1), in Arabidopsis thaliana, using an agar plate root reorientation assay. We found that, under NH4(+) stress, gsa-1 displayed increased loss of root gravitropism. Gene cloning and sequencing revealed that gsa-1 contains a G to C transversion mutation at the highly conserved 5'-GT splice position of intron 10 of ARG1 (ALTERED RESPONSE TO GRAVITY1), known to participate in the transduction of the root gravity signal. Genetic complement tests established the locus of GSA-1/ARG1 and its role in resistance to NH4 (+) inhibition on root gravitropism. GSA-1/ARG1 is required for normal AUX1 expression and basipetal auxin transport in root apices. In addition, PIN-FORMED2 (PIN2) is proposed as a target in the reduction of root gravitropism under NH4(+) stress, a response which can be antagonized by the GSA-1/ARG1-dependent pathway. These results suggest that GSA-1/ARG1 protects root gravitropism in Arabidopsis thaliana under ammonium stress.
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Affiliation(s)
- Na Zou
- College of Landscape and Art, Jiangxi Agricultural University, Nanchang, 330045, China
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, 210008, China
| | - Baohai Li
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, 210008, China
| | - Hao Chen
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
| | - Yanhua Su
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, 210008, China
| | - Herbert J Kronzucker
- Department of Biological Sciences, University of Toronto, 1265 Military Trail, Toronto, ON, M1C 1A4, Canada
| | - Liming Xiong
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
| | - František Baluška
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, D-53115, Bonn, Germany
| | - Weiming Shi
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, 210008, China
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63
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Yokawa K, Kagenishi T, Baluška F. Root photomorphogenesis in laboratory-maintained Arabidopsis seedlings. TRENDS IN PLANT SCIENCE 2013; 18:117-9. [PMID: 23395309 DOI: 10.1016/j.tplants.2013.01.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 01/04/2013] [Accepted: 01/07/2013] [Indexed: 05/04/2023]
Abstract
In nature, root systems of most terrestrial plants are underground in darkness. Nevertheless, several photoreceptors have been found in roots and light-responsive mechanisms allowing roots to escape from strong light conditions have been discovered. In transparent Petri dishes, regular light exposure affects root morphology and behavior. We advocate the use of darkened Petri dishes to allow roots to be kept in darkness, thus mimicking more closely the conditions in nature.
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Affiliation(s)
- Ken Yokawa
- IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany
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64
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Xu W, Ding G, Yokawa K, Baluška F, Li QF, Liu Y, Shi W, Liang J, Zhang J. An improved agar-plate method for studying root growth and response of Arabidopsis thaliana. Sci Rep 2013; 3:1273. [PMID: 23429403 PMCID: PMC3572446 DOI: 10.1038/srep01273] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 01/30/2013] [Indexed: 11/20/2022] Open
Abstract
Arabidopsis thaliana is a widely used model plant for plant biology research. Under traditional agar-plate culture system (TPG, traditional plant-growing), both plant shoots and roots are exposed to illumination, and roots are grown in sucrose-added medium. This is not a natural environment for the roots and may cause artifact responses. We have developed an improved agar-plate culture system (IPG, improved plant-growing) where shoots are illuminated but roots are grown in darkness without sucrose addition. Compared to TPG, IPG produced plants with significantly less total root length, lateral root length and root hair density, although their primary roots were longer. Root gravitropism, PIN2 (an auxin efflux carrier) abundance, H⁺ efflux or Ca²⁺ influx in root apexes, were weaker in IPG-grown roots than those in TPG-grown roots. We conclude that IPG offers a more natural way to study the root growth and response of Arabidopsis thaliana.
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Affiliation(s)
- Weifeng Xu
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
- These authors contributed equally to this work
| | - Guochang Ding
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- These authors contributed equally to this work
| | - Ken Yokawa
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115 Bonn, Germany
| | - František Baluška
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115 Bonn, Germany
| | - Qian-Feng Li
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong
| | - Yinggao Liu
- College of Life Science, Shandong Agricultural University, Taian, China
| | - Weiming Shi
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Jiansheng Liang
- Department of Biology, South University of Science and Technology of China, Shenzhen, 518055, China
| | - Jianhua Zhang
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong
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65
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Burbach C, Markus K, Zhang Y, Schlicht M, Baluška F. Photophobic behavior of maize roots. PLANT SIGNALING & BEHAVIOR 2012; 7:874-8. [PMID: 22751294 PMCID: PMC3583978 DOI: 10.4161/psb.21012] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Primary roots of young maize seedlings showed peculiar growth behavior when challenged by placing them on a slope, or if whole seedlings were turned upside down. Importantly, this behavior was dependent on the light conditions. If roots were placed on slopes in the dark, they performed "crawling" behavior and advanced rapidly up the slope. However, as soon as these roots were illuminated, their crawling movements along their horizontal paths slowed down, and instead tried to grow downwards along the gravity vector. A similar light-induced switch in the root behavior was observed when roots were inverted, by placing them in thin glass capillaries. As long as they were kept in the darkness, they showed rapid growth against the gravity vector. If illuminated, these inverted roots rapidly accomplished U-turns and grew down along the gravity vector, eventually escaping from the capillaries upon reaching their open ends. De-capped roots, although growing vigorously, did not display these light-induced photophobic growth responses. We can conclude that intact root cap is essential for the photophobic root behavior in maize.
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66
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Shi J, Liu M, Shi J, Zheng G, Wang Y, Wang J, Chen Y, Lu C, Yin W. Reference gene selection for qPCR in Ammopiptanthus mongolicus under abiotic stresses and expression analysis of seven ROS-scavenging enzyme genes. PLANT CELL REPORTS 2012; 31:1245-54. [PMID: 22451089 DOI: 10.1007/s00299-012-1245-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 02/14/2012] [Accepted: 02/21/2012] [Indexed: 05/08/2023]
Abstract
Ammopiptanthus mongolicus, the only evergreen broadleaf shrub endemic to the northwest desert of China, is a valuable species for plant abiotic stress research. No report has so far described the selection of reference genes to get stringent normalization for qPCR in A. mongolicus. This work identified reliable reference genes for normalization of qPCR data in A. mongolicus under abiotic stresses from 14 reference gene candidates (UBQ, Tub1, Tub2, Abc1, Ubc1, Ubc2, Ubc4, Ubc5, eIF1, eIF2, eIF3, eIF4, EF1, EF2), and used the most suitable combination of reference genes to normalize the expression profiles of seven ROS-scavenging enzyme genes (AmSOD, AmAPX, AmGPX, AmCAT, AmGLR, AmPrx, and AmTrx). We set a series of 22 experimental samples covering the control and different time points under cold, dry, salt, and heat stresses. According to geNorm and NormFinder, the combination of eIF1 and eIF3 was best for accurate normalization across all the treatments, confirmed by normalizing qPCR data with AmHsp90. In contrast, these data show that Tub1, Abc1, and EF1 are not suitable reference gene candidates. After being normalized against eIF1 and eIF3, the seven ROS-scavenging enzyme genes exhibited differentially up- or down-regulated expression patterns. AmSOD and AmGPX were up-regulated by all four treatments, indicating that they may participate in an anti-oxidative mechanism under abiotic stresses in A. mongolicus. AmCAT exhibited a much higher expression level than AmAPX, AmPrx, and AmGPX, suggesting a principle role in detoxifying excessive H₂O₂. AmSOD, AmGPX and AmAPX showing the most abundant transcripts under heat, AmCAT and AmGLR under drought, and AmPrx under salt, were observed. Expression patterns of the seven ROS-scavenging enzyme genes suggest different antioxidant protection roles of these genes under abiotic stresses. These results are valuable for future research on gene expression and abiotic stress tolerance in A. mongolicus.
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Affiliation(s)
- Jing Shi
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
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