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Kirschner GK, Hochholdinger F, Salvi S, Bennett MJ, Huang G, Bhosale RA. Genetic regulation of the root angle in cereals. TRENDS IN PLANT SCIENCE 2024; 29:814-822. [PMID: 38402016 DOI: 10.1016/j.tplants.2024.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 01/20/2024] [Accepted: 01/30/2024] [Indexed: 02/26/2024]
Abstract
The root angle plays a critical role in efficiently capturing nutrients and water from different soil layers. Steeper root angles enable access to mobile water and nitrogen from deeper soil layers, whereas shallow root angles facilitate the capture of immobile phosphorus from the topsoil. Thus, understanding the genetic regulation of the root angle is crucial for breeding crop varieties that can efficiently capture resources and enhance yield. Moreover, this understanding can contribute to developing varieties that effectively sequester carbon in deeper soil layers, supporting global carbon mitigation efforts. Here we review and consolidate significant recent discoveries regarding the molecular components controlling root angle in cereal crop species and outline the remaining research gaps in this field.
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Affiliation(s)
| | - Frank Hochholdinger
- INRES, Institute of Crop Science and Resource Conservation, Crop Functional Genomics, University of Bonn, 53113 Bonn, Germany
| | - Silvio Salvi
- Department of Agricultural and Food Sciences, University of Bologna, 40127 Bologna, Italy
| | - Malcolm J Bennett
- School of Biosciences, University of Nottingham, LE12 5RD Nottingham, UK
| | - Guoqiang Huang
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
| | - Rahul A Bhosale
- School of Biosciences, University of Nottingham, LE12 5RD Nottingham, UK; International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502324, Telangana, India.
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2
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Li J, Sheng Y, Xu H, Li Q, Lin X, Zhou Y, Zhao Y, Song X, Wang J. Transcriptome and hormone metabolome reveal the mechanism of stem bending in water lily ( Nymphaea tetragona) cut-flowers. FRONTIERS IN PLANT SCIENCE 2023; 14:1195389. [PMID: 37746018 PMCID: PMC10515221 DOI: 10.3389/fpls.2023.1195389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 08/24/2023] [Indexed: 09/26/2023]
Abstract
Water lilies are popular ornamental cut-flowers with significant economic and cultural value. However, stem bending affects the preservation of cut-flowers during their vase life. To gain further insights into the molecular mechanisms of stem bending, transcriptome profiling, hormone measurement, and morphological analysis were performed using the stems of the 'Blue Bird' water lily. Transcriptome analysis revealed that 607 differentially expressed genes (DEGs) were associated with the dorsal and ventral stems of the water lily, of which 247 were up-regulated and 360 were down-regulated. Significant differences in genes associated with plant hormones, calcium ions, glucose metabolism, and photosynthesis pathways genes involved in the dorsal and ventral areas of the curved stem. In particular, DEGs were associated with the hormone synthesis, gravity response, starch granules, Ca2+ ions, and photosynthesis. The results of qRT-PCR were consistent with that of the transcriptome sequence analysis. A total of 12 hormones were detected, of which abscisic acid, indole-3-carboxaldehyde, indole-3-carboxaldehyde and jasmonic acid were significantly differentially expressed in the dorsal and ventral stems, and were significantly higher in the dorsal stem than in the ventral stem. The cell morphology in the dorsal and ventral areas of the curved stem clearly changed during vase life. The direction of starch granule settlement was consistent with the bending direction of the water lily stem, as well as the direction of gravity. In conclusion, stem bending in water lily cut-flowers is regulated by multiple factors and genes. This study provides an important theoretical basis for understanding the complex regulatory mechanism of water lily stem bending.
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Affiliation(s)
- Jie Li
- Key Laboratory of Genetics and Germplasm Innovation of Tropical Forest Trees and Ornamental Plants, Ministry of Education, College of Forestry, Hainan University, Haikou, Hainan, China
- Key Laboratory of Germplasm Resources Biology of Tropical Special Ornamental Plants of Hainan, Haikou, Hainan, China
| | - Yuhui Sheng
- Key Laboratory of Genetics and Germplasm Innovation of Tropical Forest Trees and Ornamental Plants, Ministry of Education, College of Forestry, Hainan University, Haikou, Hainan, China
- Key Laboratory of Germplasm Resources Biology of Tropical Special Ornamental Plants of Hainan, Haikou, Hainan, China
- College of Agricultural, Hengxing University, Qingdao, Shandong, China
| | - Huixian Xu
- Key Laboratory of Genetics and Germplasm Innovation of Tropical Forest Trees and Ornamental Plants, Ministry of Education, College of Forestry, Hainan University, Haikou, Hainan, China
- Key Laboratory of Germplasm Resources Biology of Tropical Special Ornamental Plants of Hainan, Haikou, Hainan, China
| | - Qinxue Li
- Key Laboratory of Genetics and Germplasm Innovation of Tropical Forest Trees and Ornamental Plants, Ministry of Education, College of Forestry, Hainan University, Haikou, Hainan, China
- Key Laboratory of Germplasm Resources Biology of Tropical Special Ornamental Plants of Hainan, Haikou, Hainan, China
| | - Xiuya Lin
- Key Laboratory of Genetics and Germplasm Innovation of Tropical Forest Trees and Ornamental Plants, Ministry of Education, College of Forestry, Hainan University, Haikou, Hainan, China
- Key Laboratory of Germplasm Resources Biology of Tropical Special Ornamental Plants of Hainan, Haikou, Hainan, China
| | - Yang Zhou
- Key Laboratory of Genetics and Germplasm Innovation of Tropical Forest Trees and Ornamental Plants, Ministry of Education, College of Forestry, Hainan University, Haikou, Hainan, China
- Key Laboratory of Germplasm Resources Biology of Tropical Special Ornamental Plants of Hainan, Haikou, Hainan, China
| | - Ying Zhao
- Key Laboratory of Genetics and Germplasm Innovation of Tropical Forest Trees and Ornamental Plants, Ministry of Education, College of Forestry, Hainan University, Haikou, Hainan, China
- Key Laboratory of Germplasm Resources Biology of Tropical Special Ornamental Plants of Hainan, Haikou, Hainan, China
| | - Xiqiang Song
- Key Laboratory of Genetics and Germplasm Innovation of Tropical Forest Trees and Ornamental Plants, Ministry of Education, College of Forestry, Hainan University, Haikou, Hainan, China
- Key Laboratory of Germplasm Resources Biology of Tropical Special Ornamental Plants of Hainan, Haikou, Hainan, China
| | - Jian Wang
- Key Laboratory of Genetics and Germplasm Innovation of Tropical Forest Trees and Ornamental Plants, Ministry of Education, College of Forestry, Hainan University, Haikou, Hainan, China
- Key Laboratory of Germplasm Resources Biology of Tropical Special Ornamental Plants of Hainan, Haikou, Hainan, China
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3
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Ocampo-Hernández B, Gutiérrez Mireles ER, Gutiérrez-Aguilar M. Morphology and permeability transitions in plant mitochondria: Different aspects of the same event? BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148586. [PMID: 35772521 DOI: 10.1016/j.bbabio.2022.148586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
Plant mitochondria are sensitive organelles affected by changing environmental stressors. Upon heat shock or the presence of reactive oxygen species, plant mitochondria undergo in vivo morphological derangements associated with the extensively characterized opening of the mitochondrial permeability transition pore. Nevertheless, the classic mitochondrial permeability transition is known to be triggered by calcium overload causing mitochondrial swelling and dysfunction. Here we review evidence concerning calcium handling, permeability transition and mitochondrial impairments in plants, supporting the notion that the mitochondrial morphology transition is an in vivo indicator of the permeability transition.
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Affiliation(s)
- Bryan Ocampo-Hernández
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México City, México
| | - Emilia R Gutiérrez Mireles
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México City, México
| | - Manuel Gutiérrez-Aguilar
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México City, México.
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Han H, Adamowski M, Qi L, Alotaibi SS, Friml J. PIN-mediated polar auxin transport regulations in plant tropic responses. THE NEW PHYTOLOGIST 2021; 232:510-522. [PMID: 34254313 DOI: 10.1111/nph.17617] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 07/03/2021] [Indexed: 05/27/2023]
Abstract
Tropisms, growth responses to environmental stimuli such as light or gravity, are spectacular examples of adaptive plant development. The plant hormone auxin serves as a major coordinative signal. The PIN auxin exporters, through their dynamic polar subcellular localizations, redirect auxin fluxes in response to environmental stimuli and the resulting auxin gradients across organs underlie differential cell elongation and bending. In this review, we discuss recent advances concerning regulations of PIN polarity during tropisms, focusing on PIN phosphorylation and trafficking. We also cover how environmental cues regulate PIN actions during tropisms, as well as the crucial role of auxin feedback on PIN polarity during bending termination. Finally, the interactions between different tropisms are reviewed to understand plant adaptive growth in the natural environment.
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Affiliation(s)
- Huibin Han
- Institute of Science and Technology Austria, Klosterneuburg, 3400, Austria
- Research Center for Plant Functional Genes and Tissue Culture Technology, College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Maciek Adamowski
- Institute of Science and Technology Austria, Klosterneuburg, 3400, Austria
| | - Linlin Qi
- Institute of Science and Technology Austria, Klosterneuburg, 3400, Austria
| | - Saqer S Alotaibi
- Department of Biotechnology, Taif University, PO Box 11099, Taif, 21944, Kingdom of Saudi Arabia
| | - Jiří Friml
- Institute of Science and Technology Austria, Klosterneuburg, 3400, Austria
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Cséplő Á, Zsigmond L, Andrási N, Baba AI, Labhane NM, Pető A, Kolbert Z, Kovács HE, Steinbach G, Szabados L, Fehér A, Rigó G. The AtCRK5 Protein Kinase Is Required to Maintain the ROS NO Balance Affecting the PIN2-Mediated Root Gravitropic Response in Arabidopsis. Int J Mol Sci 2021; 22:5979. [PMID: 34205973 PMCID: PMC8197844 DOI: 10.3390/ijms22115979] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/24/2021] [Accepted: 05/28/2021] [Indexed: 11/18/2022] Open
Abstract
The Arabidopsis AtCRK5 protein kinase is involved in the establishment of the proper auxin gradient in many developmental processes. Among others, the Atcrk5-1 mutant was reported to exhibit a delayed gravitropic response via compromised PIN2-mediated auxin transport at the root tip. Here, we report that this phenotype correlates with lower superoxide anion (O2•-) and hydrogen peroxide (H2O2) levels but a higher nitric oxide (NO) content in the mutant root tips in comparison to the wild type (AtCol-0). The oxidative stress inducer paraquat (PQ) triggering formation of O2•- (and consequently, H2O2) was able to rescue the gravitropic response of Atcrk5-1 roots. The direct application of H2O2 had the same effect. Under gravistimulation, correct auxin distribution was restored (at least partially) by PQ or H2O2 treatment in the mutant root tips. In agreement, the redistribution of the PIN2 auxin efflux carrier was similar in the gravistimulated PQ-treated mutant and untreated wild type roots. It was also found that PQ-treatment decreased the endogenous NO level at the root tip to normal levels. Furthermore, the mutant phenotype could be reverted by direct manipulation of the endogenous NO level using an NO scavenger (cPTIO). The potential involvement of AtCRK5 protein kinase in the control of auxin-ROS-NO-PIN2-auxin regulatory loop is discussed.
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Affiliation(s)
- Ágnes Cséplő
- Biological Research Centre (BRC), Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), H-6726 Szeged, Hungary; (Á.C.); (L.Z.); (N.A.); (A.I.B.); (H.E.K.); (G.S.); (L.S.); (A.F.)
| | - Laura Zsigmond
- Biological Research Centre (BRC), Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), H-6726 Szeged, Hungary; (Á.C.); (L.Z.); (N.A.); (A.I.B.); (H.E.K.); (G.S.); (L.S.); (A.F.)
| | - Norbert Andrási
- Biological Research Centre (BRC), Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), H-6726 Szeged, Hungary; (Á.C.); (L.Z.); (N.A.); (A.I.B.); (H.E.K.); (G.S.); (L.S.); (A.F.)
| | - Abu Imran Baba
- Biological Research Centre (BRC), Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), H-6726 Szeged, Hungary; (Á.C.); (L.Z.); (N.A.); (A.I.B.); (H.E.K.); (G.S.); (L.S.); (A.F.)
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
| | - Nitin M. Labhane
- Department of Botany, Bhavan’s College Andheri West, Mumbai 400058, India;
| | - Andrea Pető
- Department of Plant Biology, University of Szeged, 52. Középfasor, H-6726 Szeged, Hungary; (A.P.); (Z.K.)
- Food Chain Safety Center Nonprofit Ltd., H-1024 Budapest, Hungary
| | - Zsuzsanna Kolbert
- Department of Plant Biology, University of Szeged, 52. Középfasor, H-6726 Szeged, Hungary; (A.P.); (Z.K.)
| | - Hajnalka E. Kovács
- Biological Research Centre (BRC), Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), H-6726 Szeged, Hungary; (Á.C.); (L.Z.); (N.A.); (A.I.B.); (H.E.K.); (G.S.); (L.S.); (A.F.)
- Budapest, Kossuth Lajos Sugárút, 72/D, H-6724 Szeged, Hungary
| | - Gábor Steinbach
- Biological Research Centre (BRC), Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), H-6726 Szeged, Hungary; (Á.C.); (L.Z.); (N.A.); (A.I.B.); (H.E.K.); (G.S.); (L.S.); (A.F.)
- Cellular Imaging Laboratory, Biological Research Centre, Eötvös Loránd Research Network, H-6726 Szeged, Hungary
| | - László Szabados
- Biological Research Centre (BRC), Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), H-6726 Szeged, Hungary; (Á.C.); (L.Z.); (N.A.); (A.I.B.); (H.E.K.); (G.S.); (L.S.); (A.F.)
| | - Attila Fehér
- Biological Research Centre (BRC), Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), H-6726 Szeged, Hungary; (Á.C.); (L.Z.); (N.A.); (A.I.B.); (H.E.K.); (G.S.); (L.S.); (A.F.)
- Department of Plant Biology, University of Szeged, 52. Középfasor, H-6726 Szeged, Hungary; (A.P.); (Z.K.)
| | - Gábor Rigó
- Biological Research Centre (BRC), Institute of Plant Biology, Eötvös Loránd Research Network (ELKH), H-6726 Szeged, Hungary; (Á.C.); (L.Z.); (N.A.); (A.I.B.); (H.E.K.); (G.S.); (L.S.); (A.F.)
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The gravistimulation-induced very slow Ca 2+ increase in Arabidopsis seedlings requires MCA1, a Ca 2+-permeable mechanosensitive channel. Sci Rep 2021; 11:227. [PMID: 33420331 PMCID: PMC7794229 DOI: 10.1038/s41598-020-80733-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 12/23/2020] [Indexed: 12/11/2022] Open
Abstract
Gravity is a critical environmental factor affecting the morphology and function of plants on Earth. Gravistimulation triggered by changes in the gravity vector induces an increase in the cytoplasmic free calcium ion concentration ([Ca2+]c) as an early process of gravity sensing; however, its role and molecular mechanism are still unclear. When seedlings of Arabidopsis thaliana expressing apoaequorin were rotated from the upright position to the upside-down position, a biphasic [Ca2+]c-increase composed of a fast-transient [Ca2+]c-increase followed by a slow [Ca2+]c-increase was observed. We find here a novel type [Ca2+]c-increase, designated a very slow [Ca2+]c-increase that is observed when the seedlings were rotated back to the upright position from the upside-down position. The very slow [Ca2+]c-increase was strongly attenuated in knockout seedlings defective in MCA1, a mechanosensitive Ca2+-permeable channel (MSCC), and was partially restored in MCA1-complemented seedlings. The mechanosensitive ion channel blocker, gadolinium, blocked the very slow [Ca2+]c-increase. This is the first report suggesting the possible involvement of MCA1 in an early event related to gravity sensing in Arabidopsis seedlings.
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Abe Y, Meguriya K, Matsuzaki T, Sugiyama T, Yoshikawa HY, Morita MT, Toyota M. Micromanipulation of amyloplasts with optical tweezers in Arabidopsis stems. PLANT BIOTECHNOLOGY (TOKYO, JAPAN) 2020; 37:405-415. [PMID: 33850427 PMCID: PMC8034693 DOI: 10.5511/plantbiotechnology.20.1201a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/01/2020] [Indexed: 05/25/2023]
Abstract
Intracellular sedimentation of highly dense, starch-filled amyloplasts toward the gravity vector is likely a key initial step for gravity sensing in plants. However, recent live-cell imaging technology revealed that most amyloplasts continuously exhibit dynamic, saltatory movements in the endodermal cells of Arabidopsis stems. These complicated movements led to questions about what type of amyloplast movement triggers gravity sensing. Here we show that a confocal microscope equipped with optical tweezers can be a powerful tool to trap and manipulate amyloplasts noninvasively, while simultaneously observing cellular responses such as vacuolar dynamics in living cells. A near-infrared (λ=1064 nm) laser that was focused into the endodermal cells at 1 mW of laser power attracted and captured amyloplasts at the laser focus. The optical force exerted on the amyloplasts was theoretically estimated to be up to 1 pN. Interestingly, endosomes and trans-Golgi network were trapped at 30 mW but not at 1 mW, which is probably due to lower refractive indices of these organelles than that of the amyloplasts. Because amyloplasts are in close proximity to vacuolar membranes in endodermal cells, their physical interaction could be visualized in real time. The vacuolar membranes drastically stretched and deformed in response to the manipulated movements of amyloplasts by optical tweezers. Our new method provides deep insights into the biophysical properties of plant organelles in vivo and opens a new avenue for studying gravity-sensing mechanisms in plants.
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Affiliation(s)
- Yoshinori Abe
- Department of Biochemistry and Molecular Biology, Saitama University, Saitama 338-8570, Japan
| | - Keisuke Meguriya
- Department of Chemistry, Saitama University, Saitama 338-8570, Japan
| | - Takahisa Matsuzaki
- Division of Strategic Research and Development, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Teruki Sugiyama
- Department of Applied Chemistry, National Chiao Tung University, Hsinchu 30010, Taiwan
- Division of Materials Science, Nara Institute of Science and Technology, Nara 630-0192, Japan
- Center for Emergent Functional Matter Science, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Hiroshi Y. Yoshikawa
- Department of Chemistry, Saitama University, Saitama 338-8570, Japan
- Division of Strategic Research and Development, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Miyo Terao Morita
- Division of Plant Environmental Responses, National Institute for Basic Biology, Aichi 444-8585, Japan
| | - Masatsugu Toyota
- Department of Biochemistry and Molecular Biology, Saitama University, Saitama 338-8570, Japan
- Department of Botany, University of Wisconsin, Madison, WI 53706, USA
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Su SH, Keith MA, Masson PH. Gravity Signaling in Flowering Plant Roots. PLANTS 2020; 9:plants9101290. [PMID: 33003550 PMCID: PMC7601833 DOI: 10.3390/plants9101290] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/24/2020] [Accepted: 09/27/2020] [Indexed: 12/28/2022]
Abstract
Roots typically grow downward into the soil where they anchor the plant and take up water and nutrients necessary for plant growth and development. While the primary roots usually grow vertically downward, laterals often follow a gravity set point angle that allows them to explore the surrounding environment. These responses can be modified by developmental and environmental cues. This review discusses the molecular mechanisms that govern root gravitropism in flowering plant roots. In this system, the primary site of gravity sensing within the root cap is physically separated from the site of curvature response at the elongation zone. Gravity sensing involves the sedimentation of starch-filled plastids (statoliths) within the columella cells of the root cap (the statocytes), which triggers a relocalization of plasma membrane-associated PIN auxin efflux facilitators to the lower side of the cell. This process is associated with the recruitment of RLD regulators of vesicular trafficking to the lower membrane by LAZY proteins. PIN relocalization leads to the formation of a lateral gradient of auxin across the root cap. Upon transmission to the elongation zone, this auxin gradient triggers a downward curvature. We review the molecular mechanisms that control this process in primary roots and discuss recent insights into the regulation of oblique growth in lateral roots and its impact on root-system architecture, soil exploration and plant adaptation to stressful environments.
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Rath M, Dümmer M, Galland P, Forreiter C. A gravitropic stimulus alters the distribution of EHB1, a negative effector of root gravitropism in Arabidopsis. PLANT DIRECT 2020; 4:e00215. [PMID: 32318652 PMCID: PMC7171323 DOI: 10.1002/pld3.215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 02/07/2020] [Accepted: 03/12/2020] [Indexed: 05/30/2023]
Abstract
In Arabidopsis gravitropism is affected by two antagonistically interacting proteins, AGD12 (ADP-RIBOSYLATION FACTOR GTPase-ACTIVATING PROTEIN) and EHB1 (ENHANCED BENDING 1). While AGD12 enhances gravitropic bending, EHB1 functions as a negative element. To further characterize their cellular function, we analyzed the location of AGD12-GFP and EHB1-GFP fusion proteins in the root apex by confocal laser-scanning microscopy after gravitropic stimulation. For this purpose, a novel method of microscopic visualization was developed with the objective and root axes aligned allowing an improved and comparable discernment of the fluorescence gradient across the columella. In vertical roots, both proteins were localized symmetrically and occurred preferentially in the outer layers of the columella. After reorienting roots horizontally, EHB1-GFP accumulated in the upper cell layers of the columella, that is, opposite to the gravity vector. The gravity-induced EHB1-GFP asymmetry disappeared after reorienting the roots back into the vertical position. No such asymmetry occurred with AGD12-GFP. Our findings reveal that after a gravitropic stimulus the cellular ratio between EHB1 and AGD12 is affected differently in the upper and lower part of the root. Its impact as a significant signaling event that ultimately affects the redirection of the lateral auxin flux toward the lower site of the root is discussed.
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Affiliation(s)
- Magnus Rath
- Fachbereich BiologiePhilipps‐Universität MarburgMarburgGermany
| | - Michaela Dümmer
- Fachbereich BiologiePhilipps‐Universität MarburgMarburgGermany
| | - Paul Galland
- Fachbereich BiologiePhilipps‐Universität MarburgMarburgGermany
| | - Christoph Forreiter
- Fachbereich BiologiePhilipps‐Universität MarburgMarburgGermany
- Institut für BiologieUniversität SiegenSiegenGermany
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10
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Muthert LWF, Izzo LG, van Zanten M, Aronne G. Root Tropisms: Investigations on Earth and in Space to Unravel Plant Growth Direction. FRONTIERS IN PLANT SCIENCE 2019; 10:1807. [PMID: 32153599 PMCID: PMC7047216 DOI: 10.3389/fpls.2019.01807] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 12/24/2019] [Indexed: 05/12/2023]
Abstract
Root tropisms are important responses of plants, allowing them to adapt their growth direction. Research on plant tropisms is indispensable for future space programs that envisage plant-based life support systems for long-term missions and planet colonization. Root tropisms encompass responses toward or away from different environmental stimuli, with an underexplored level of mechanistic divergence. Research into signaling events that coordinate tropistic responses is complicated by the consistent coincidence of various environmental stimuli, often interacting via shared signaling mechanisms. On Earth the major determinant of root growth direction is the gravitational vector, acting through gravitropism and overruling most other tropistic responses to environmental stimuli. Critical advancements in the understanding of root tropisms have been achieved nullifying the gravitropic dominance with experiments performed in the microgravity environment. In this review, we summarize current knowledge on root tropisms to different environmental stimuli. We highlight that the term tropism must be used with care, because it can be easily confused with a change in root growth direction due to asymmetrical damage to the root, as can occur in apparent chemotropism, electrotropism, and magnetotropism. Clearly, the use of Arabidopsis thaliana as a model for tropism research contributed much to our understanding of the underlying regulatory processes and signaling events. However, pronounced differences in tropisms exist among species, and we argue that these should be further investigated to get a more comprehensive view of the signaling pathways and sensors. Finally, we point out that the Cholodny-Went theory of asymmetric auxin distribution remains to be the central and unifying tropistic mechanism after 100 years. Nevertheless, it becomes increasingly clear that the theory is not applicable to all root tropistic responses, and we propose further research to unravel commonalities and differences in the molecular and physiological processes orchestrating root tropisms.
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Affiliation(s)
| | - Luigi Gennaro Izzo
- Department of Agricultural Sciences, University of Naples Federico II, Naples, Italy
- *Correspondence: Luigi Gennaro Izzo,
| | - Martijn van Zanten
- Molecular Plant Physiology, Institute of Environmental Biology, Utrecht University, Utrecht, Netherlands
| | - Giovanna Aronne
- Department of Agricultural Sciences, University of Naples Federico II, Naples, Italy
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11
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Electrophysiological experiments in microgravity: lessons learned and future challenges. NPJ Microgravity 2018; 4:7. [PMID: 29619409 PMCID: PMC5876337 DOI: 10.1038/s41526-018-0042-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 03/07/2018] [Accepted: 03/07/2018] [Indexed: 02/08/2023] Open
Abstract
Advances in electrophysiological experiments have led to the discovery of mechanosensitive ion channels (MSCs) and the identification of the physiological function of specific MSCs. They are believed to play important roles in mechanosensitive pathways by allowing for cells to sense their mechanical environment. However, the physiological function of many MSCs has not been conclusively identified. Therefore, experiments have been developed that expose cells to various mechanical loads, such as shear flow, membrane indentation, osmotic challenges and hydrostatic pressure. In line with these experiments, mechanical unloading, as experienced in microgravity, represents an interesting alternative condition, since exposure to microgravity leads to a series of physiological adaption processes. As outlined in this review, electrophysiological experiments performed in microgravity have shown an influence of gravity on biological functions depending on ion channels at all hierarchical levels, from the cellular level to organs. In this context, calcium signaling represents an interesting cellular pathway, as it involves the direct action of calcium-permeable ion channels, and specific gravitatic cells have linked graviperception to this pathway. Multiple key proteins in the graviperception pathways have been identified. However, measurements on vertebrae cells have revealed controversial results. In conclusion, electrophysiological experiments in microgravity have shown that ion-channel-dependent physiological processes are altered in mechanically unloaded conditions. Future experiments may provide a better understanding of the underlying mechanisms.
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Zajączkowska U, Barlow PW. The effect of lunisolar tidal acceleration on stem elongation growth, nutations and leaf movements in peppermint (Mentha × piperita L.). PLANT BIOLOGY (STUTTGART, GERMANY) 2017; 19:630-642. [PMID: 28258604 DOI: 10.1111/plb.12561] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 02/27/2017] [Indexed: 06/06/2023]
Abstract
Orbital movement of the Moon generates a system of gravitational fields that periodically alter the gravitational force on Earth. This lunar tidal acceleration (Etide) is known to act as an external environmental factor affecting many growth and developmental phenomena in plants. Our study focused on the lunar tidal influence on stem elongation growth, nutations and leaf movements of peppermint. Plants were continuously recorded with time-lapse photography under constant illumination as well in constant illumination following 5 days of alternating dark-light cycles. Time courses of shoot movements were correlated with contemporaneous time courses of the Etide estimates. Optical microscopy and SEM were used in anatomical studies. All plant shoot movements were synchronised with changes in the lunisolar acceleration. Using a periodogram, wavelet analysis and local correlation index, a convergence was found between the rhythms of lunisolar acceleration and the rhythms of shoot growth. Also observed were cyclical changes in the direction of rotation of stem apices when gravitational dynamics were at their greatest. After contrasting dark-light cycle experiments, nutational rhythms converged to an identical phase relationship with the Etide and almost immediately their renewed movements commenced. Amplitudes of leaf movements decreased during leaf growth up to the stage when the leaf was fully developed; the periodicity of leaf movements correlated with the Etide rhythms. For the fist time, it was documented that lunisolar acceleration is an independent rhythmic environmental signal capable of influencing the dynamics of plant stem elongation. This phenomenon is synchronised with the known effects of Etide on nutations and leaf movements.
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Affiliation(s)
- U Zajączkowska
- Department of Forest Botany, Faculty of Forestry, Warsaw University of Life Sciences, Warsaw, Poland
| | - P W Barlow
- School of Biological Sciences, University of Bristol, Bristol, UK
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Häder DP, Braun M, Grimm D, Hemmersbach R. Gravireceptors in eukaryotes-a comparison of case studies on the cellular level. NPJ Microgravity 2017; 3:13. [PMID: 28649635 PMCID: PMC5460273 DOI: 10.1038/s41526-017-0018-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 01/27/2017] [Accepted: 03/09/2017] [Indexed: 01/03/2023] Open
Abstract
We have selected five evolutionary very different biological systems ranging from unicellular protists via algae and higher plants to human cells showing responses to the gravity vector of the Earth in order to compare their graviperception mechanisms. All these systems use a mass, which may either by a heavy statolith or the whole content of the cell heavier than the surrounding medium to operate on a gravireceptor either by exerting pressure or by pulling on a cytoskeletal element. In many cases the receptor seems to be a mechanosensitive ion channel activated by the gravitational force which allows a gated ion flux across the membrane when activated. This has been identified in many systems to be a calcium current, which in turn activates subsequent elements of the sensory transduction chain, such as calmodulin, which in turn results in the activation of ubiquitous enzymes, gene expression activation or silencing. Naturally, the subsequent responses to the gravity stimulus differ widely between the systems ranging from orientational movement and directed growth to physiological reactions and adaptation to the environmental conditions.
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Affiliation(s)
- Donat-P. Häder
- Erlangen-Nürnberg, Dept. Biol. Neue Str. 9, Emeritus from Friedrich-Alexander Universität, Möhrendorf, 91096 Germany
| | - Markus Braun
- Gravitational Biology, Universität Bonn, Kirschallee 1, Bonn, 53115 Germany
| | - Daniela Grimm
- Department of Biomedicine, Pharmacology, Aarhus University, Aarhus C, DK 8000 Denmark
| | - Ruth Hemmersbach
- Institute of Aerospace Medicine, Gravitational Biology, DLR (German Aerospace Center), Cologne, Linder Höhe 51147 Germany
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Yan S, Wu G. Predicting Crystallization Propensity of Proteins from Arabidopsis Thaliana. Biol Proced Online 2015; 17:16. [PMID: 26604856 PMCID: PMC4657326 DOI: 10.1186/s12575-015-0029-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 11/12/2015] [Indexed: 12/02/2022] Open
Abstract
Background Many studies have correlated characteristics of amino acids with crystallization propensity, as part of the effort to determine the factors that affect the propensity of protein crystallization. However, these characteristics are constant; that is, the encoded amino acid sequences have the same value for each type of amino acid. To overcome this inflexibility, three dynamic characteristics of amino acids and protein were introduced to analyze the crystallization propensity of proteins. Both logistic regression and neural network models were used to correlate each of two dynamic characteristics with the crystallization propensity of 301 proteins from Arabidopsis thaliana, and their results were compared with those obtained from each of 531 constant amino acid characteristics, which served as the benchmark. Results The neural network model was more powerful for predicting the crystallization propensity of proteins than the logistic regression model. Compared with the benchmark, the dynamic characteristics of amino acids provided good prediction results for the crystallization propensity, and the distribution probability gave the highest sensitivity. Using 90 % accuracy as a cutoff point, the predictable portion of A. thaliana portions was ranked, and the statistical analysis showed that the larger the predictable portion, the better the prediction. Conclusions These results demonstrate that dynamic characteristics have a certain relationship with the crystallization propensity, and they could be helpful for the prediction of protein crystallization, which may provide a theoretical concept for certain proteins before conducting experimental crystallization. Electronic supplementary material The online version of this article (doi:10.1186/s12575-015-0029-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shaomin Yan
- State Key Laboratory of Non-food Biomass Enzyme Technology, National Engineering Research Center for Non-food Biorefinery, Guangxi Key Laboratory of Biorefinery, Guangxi Academy of Sciences, 98 Daling Road, Nanning, Guangxi 530007 China
| | - Guang Wu
- State Key Laboratory of Non-food Biomass Enzyme Technology, National Engineering Research Center for Non-food Biorefinery, Guangxi Key Laboratory of Biorefinery, Guangxi Academy of Sciences, 98 Daling Road, Nanning, Guangxi 530007 China
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