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Voothuluru P, Wu Y, Sharp RE. Not so hidden anymore: Advances and challenges in understanding root growth under water deficits. THE PLANT CELL 2024; 36:1377-1409. [PMID: 38382086 PMCID: PMC11062450 DOI: 10.1093/plcell/koae055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/09/2024] [Accepted: 02/15/2024] [Indexed: 02/23/2024]
Abstract
Limited water availability is a major environmental factor constraining plant development and crop yields. One of the prominent adaptations of plants to water deficits is the maintenance of root growth that enables sustained access to soil water. Despite early recognition of the adaptive significance of root growth maintenance under water deficits, progress in understanding has been hampered by the inherent complexity of root systems and their interactions with the soil environment. We highlight selected milestones in the understanding of root growth responses to water deficits, with emphasis on founding studies that have shaped current knowledge and set the stage for further investigation. We revisit the concept of integrated biophysical and metabolic regulation of plant growth and use this framework to review central growth-regulatory processes occurring within root growth zones under water stress at subcellular to organ scales. Key topics include the primary processes of modifications of cell wall-yielding properties and osmotic adjustment, as well as regulatory roles of abscisic acid and its interactions with other hormones. We include consideration of long-recognized responses for which detailed mechanistic understanding has been elusive until recently, for example hydrotropism, and identify gaps in knowledge, ongoing challenges, and opportunities for future research.
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Affiliation(s)
- Priya Voothuluru
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
- Interdisciplinary Plant Group, University of Missouri, Columbia, MO 65211, USA
| | - Yajun Wu
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA
| | - Robert E Sharp
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
- Interdisciplinary Plant Group, University of Missouri, Columbia, MO 65211, USA
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2
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Uzilday B, Takahashi K, Kobayashi A, Uzilday RO, Fujii N, Takahashi H, Turkan I. Role of Abscisic Acid, Reactive Oxygen Species, and Ca 2+ Signaling in Hydrotropism-Drought Avoidance-Associated Response of Roots. PLANTS (BASEL, SWITZERLAND) 2024; 13:1220. [PMID: 38732435 PMCID: PMC11085316 DOI: 10.3390/plants13091220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 05/13/2024]
Abstract
Plant roots exert hydrotropism in response to moisture gradients to avoid drought stress. The regulatory mechanism underlying hydrotropism involves novel regulators such as MIZ1 and GNOM/MIZ2 as well as abscisic acid (ABA), reactive oxygen species (ROS), and Ca2+ signaling. ABA, ROS, and Ca2+ signaling are also involved in plant responses to drought stress. Although the mechanism of moisture gradient perception remains largely unknown, the sensory apparatus has been reported to reside in the root elongation zone rather than in the root cap. In Arabidopsis roots, hydrotropism is mediated by the action of MIZ1 and ABA in the cortex of the elongation zone, the accumulation of ROS at the root curvature, and the variation in the cytosolic Ca2+ concentration in the entire root tip including the root cap and stele of the elongation zone. Moreover, root exposure to moisture gradients has been proposed to cause asymmetric ABA distribution or Ca2+ signaling, leading to the induction of the hydrotropic response. A comprehensive and detailed analysis of hydrotropism regulators and their signaling network in relation to the tissues required for their function is apparently crucial for understanding the mechanisms unique to root hydrotropism. Here, referring to studies on plant responses to drought stress, we summarize the recent findings relating to the role of ABA, ROS, and Ca2+ signaling in hydrotropism, discuss their functional sites and plausible networks, and raise some questions that need to be answered in future studies.
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Affiliation(s)
- Baris Uzilday
- Department of Biology, Faculty of Science, Ege University, Bornova 35100, Izmir, Turkey
| | - Kaori Takahashi
- Graduate School of Life Sciences, Tohoku University, Katahira, Sendai 980-8577, Japan
| | - Akie Kobayashi
- Graduate School of Life Sciences, Tohoku University, Katahira, Sendai 980-8577, Japan
| | - Rengin Ozgur Uzilday
- Department of Biology, Faculty of Science, Ege University, Bornova 35100, Izmir, Turkey
| | - Nobuharu Fujii
- Graduate School of Life Sciences, Tohoku University, Katahira, Sendai 980-8577, Japan
| | - Hideyuki Takahashi
- Graduate School of Life Sciences, Tohoku University, Katahira, Sendai 980-8577, Japan
- Research Center for Space Agriculture and Horticulture, Graduate School of Horticulture, Chiba University, Matsudo, Chiba 271-8510, Japan
| | - Ismail Turkan
- Department of Biology, Faculty of Science, Ege University, Bornova 35100, Izmir, Turkey
- Graduate School of Life Sciences, Tohoku University, Katahira, Sendai 980-8577, Japan
- Faculty of Agricultural Sciences and Technologies, Yasar University, University Street, No. 37-39, Bornova 35100, Izmir, Turkey
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3
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Yu B, Chao DY, Zhao Y. How plants sense and respond to osmotic stress. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2024; 66:394-423. [PMID: 38329193 DOI: 10.1111/jipb.13622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/12/2024] [Accepted: 01/18/2024] [Indexed: 02/09/2024]
Abstract
Drought is one of the most serious abiotic stresses to land plants. Plants sense and respond to drought stress to survive under water deficiency. Scientists have studied how plants sense drought stress, or osmotic stress caused by drought, ever since Charles Darwin, and gradually obtained clues about osmotic stress sensing and signaling in plants. Osmotic stress is a physical stimulus that triggers many physiological changes at the cellular level, including changes in turgor, cell wall stiffness and integrity, membrane tension, and cell fluid volume, and plants may sense some of these stimuli and trigger downstream responses. In this review, we emphasized water potential and movements in organisms, compared putative signal inputs in cell wall-containing and cell wall-free organisms, prospected how plants sense changes in turgor, membrane tension, and cell fluid volume under osmotic stress according to advances in plants, animals, yeasts, and bacteria, summarized multilevel biochemical and physiological signal outputs, such as plasma membrane nanodomain formation, membrane water permeability, root hydrotropism, root halotropism, Casparian strip and suberin lamellae, and finally proposed a hypothesis that osmotic stress responses are likely to be a cocktail of signaling mediated by multiple osmosensors. We also discussed the core scientific questions, provided perspective about the future directions in this field, and highlighted the importance of robust and smart root systems and efficient source-sink allocations for generating future high-yield stress-resistant crops and plants.
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Affiliation(s)
- Bo Yu
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, The Chinese Academy of Sciences, Shanghai, 200032, China
- Key Laboratory of Plant Carbon Capture, The Chinese Academy of Sciences, Shanghai, 200032, China
| | - Dai-Yin Chao
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, The Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yang Zhao
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, The Chinese Academy of Sciences, Shanghai, 200032, China
- Key Laboratory of Plant Carbon Capture, The Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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4
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Kalra A, Goel S, Elias AA. Understanding role of roots in plant response to drought: Way forward to climate-resilient crops. THE PLANT GENOME 2024; 17:e20395. [PMID: 37853948 DOI: 10.1002/tpg2.20395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 07/26/2023] [Accepted: 09/18/2023] [Indexed: 10/20/2023]
Abstract
Drought stress leads to a significant amount of agricultural crop loss. Thus, with changing climatic conditions, it is important to develop resilience measures in agricultural systems against drought stress. Roots play a crucial role in regulating plant development under drought stress. In this review, we have summarized the studies on the role of roots and root-mediated plant responses. We have also discussed the importance of root system architecture (RSA) and the various structural and anatomical changes that it undergoes to increase survival and productivity under drought. Various genes, transcription factors, and quantitative trait loci involved in regulating root growth and development are also discussed. A summarization of various instruments and software that can be used for high-throughput phenotyping in the field is also provided in this review. More comprehensive studies are required to help build a detailed understanding of RSA and associated traits for breeding drought-resilient cultivars.
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Affiliation(s)
- Anmol Kalra
- Department of Botany, University of Delhi, North Campus, Delhi, India
| | - Shailendra Goel
- Department of Botany, University of Delhi, North Campus, Delhi, India
| | - Ani A Elias
- ICFRE - Institute of Forest Genetics and Tree Breeding (ICFRE - IFGTB), Coimbatore, India
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5
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Dalal M, Mansi, Mayandi K. Zoom-in to molecular mechanisms underlying root growth and function under heterogeneous soil environment and abiotic stresses. PLANTA 2023; 258:108. [PMID: 37898971 DOI: 10.1007/s00425-023-04262-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 10/06/2023] [Indexed: 10/31/2023]
Abstract
MAIN CONCLUSION The review describes tissue-specific and non-cell autonomous molecular responses regulating the root system architecture and function in plants. Phenotypic plasticity of roots relies on specific molecular and tissue specific responses towards local and microscale heterogeneity in edaphic factors. Unlike gravitropism, hydrotropism in Arabidopsis is regulated by MIZU KUSSIE1 (MIZ1)-dependent asymmetric distribution of cytokinin and activation of Arabidopsis response regulators, ARR16 and ARR17 on the lower water potential side of the root leading to higher cell division and root bending. The cortex specific role of Abscisic acid (ABA)-activated SNF1-related protein kinase 2.2 (SnRK2.2) and MIZ1 in elongation zone is emerging for hydrotropic curvature. Halotropism involves clathrin-mediated internalization of PIN FORMED 2 (PIN2) proteins at the side facing higher salt concentration in the root tip, and ABA-activated SnRK2.6 mediated phosphorylation of cortical microtubule-associated protein Spiral2-like (SP2L) in the root transition zone, which results in anisotropic cell expansion and root bending away from higher salt. In hydropatterning, Indole-3-acetic acid 3 (IAA3) interacts with SUMOylated-ARF7 (Auxin response factor 7) and prevents expression of Lateral organ boundaries-domain 16 (LBD16) in air-side of the root, while on wet side of the root, IAA3 cannot repress the non-SUMOylated-ARF7 thereby leading to LBD16 expression and lateral root development. In root vasculature, ABA induces expression of microRNA165/microRNA166 in endodermis, which moves into the stele to target class III Homeodomain leucine zipper protein (HD-ZIP III) mRNA in non-cell autonomous manner. The bidirectional gradient of microRNA165/6 and HD-ZIP III mRNA regulates xylem patterning under stress. Understanding the tissue specific molecular mechanisms regulating the root responses under heterogeneous and stress environments will help in designing climate-resilient crops.
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Affiliation(s)
- Monika Dalal
- ICAR-National Institute for Plant Biotechnology, New Delhi, 110012, India.
| | - Mansi
- ICAR-National Institute for Plant Biotechnology, New Delhi, 110012, India
- Department of Biosciences, Durham University, Durham, DH1 3LE, UK
| | - Karthikeyan Mayandi
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara, 630-0192, Japan
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6
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Akita K, Miyazawa Y. Auxin biosynthesis, transport, and response directly attenuate hydrotropism in the latter stages to fine-tune root growth direction in Arabidopsis. PHYSIOLOGIA PLANTARUM 2023; 175:e14051. [PMID: 37882259 DOI: 10.1111/ppl.14051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/28/2023] [Accepted: 10/05/2023] [Indexed: 10/27/2023]
Abstract
Roots detect water potential gradients in the soil and orient toward moister areas, a response known as hydrotropism that aids drought avoidance. Although auxin is crucial in tropism, its polar transport is not essential for hydrotropism in Arabidopsis. Moreover, antiauxin treatments in Arabidopsis produced inconsistent outcomes: some studies indicated auxin action was necessary while others did not. In this study, we examined auxin's physiological role in hydrotropism. We found that inhibiting auxin biosynthesis or transport intensified hydrotropic bending not only in wild-type, but also in hydrotropism defective mutants, namely miz1-1 and miz2 plants. Given that miz1-1 and miz2 exhibited compromised hydrotropism even under clinorotated conditions, we infer that auxin biosynthesis and transport directly suppress hydrotropism. Additionally, tir1-10, afb1-3, and afb2-3 displayed augmented hydrotropism. We observed a significant delay in hydrotropic bending in arf7-1arf19-1, suggesting that ARF7 and ARF19 amplify hydrotropism in its early stages. To discern the functional ties of ARF7/19 with MIZ1 and MIZ2, we studied the hydrotropic phenotypes of arf7-1arf19-1miz1-1 and arf7-1arf19-1miz2. Both triple mutants had diminished early-stage hydrotropism yet showed partial but significant recovery in the later stages. Given MIZ1's role in reducing auxin levels and MIZ2's essentiality for MIZ1 functionality, we conclude that auxin inhibits hydrotropism downstream of MIZ1 in later stages to refine root bending. Furthermore, it is posited that gene expression driven by ARF7 and ARF19 is pivotal for early-stage root hydrotropism.
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Affiliation(s)
- Kotaro Akita
- Graduate School of Science and Engineering, Yamagata University, Yamagata, Japan
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7
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Mao B, Takahashi H, Takahashi H, Fujii N. Diversity of root hydrotropism among natural variants of Arabidopsis thaliana. JOURNAL OF PLANT RESEARCH 2022; 135:799-808. [PMID: 36149514 PMCID: PMC10039817 DOI: 10.1007/s10265-022-01412-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 09/08/2022] [Indexed: 05/30/2023]
Abstract
Root gravitropism affects root hydrotropism. The interference intensity of root gravitropism with root hydrotropism differs among plant species. However, these differences have not been well compared within a single plant species. In this study, we compared root hydrotropism in various natural variants of Arabidopsis under stationary conditions. As a result, we detected a range of root hydrotropism under stationary conditions among natural Arabidopsis variants. Comparison of root gravitropism and root hydrotropism among several Arabidopsis natural variants classified natural variants that decreased root hydrotropism into two types; namely one type that expresses root gravitropism and root hydrotropism weaker than Col-0, and the other type that expresses weaker root hydrotropism than Col-0 but expresses similar root gravitropism with Col-0. However, root hydrotropism of all examined Arabidopsis natural variants was facilitated by clinorotation. These results suggested that the interference of root gravitropism with root hydrotropism is conserved among Arabidopsis natural variants, although the intensity of root gravitropism interference with root hydrotropism differs.
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Affiliation(s)
- Boyuan Mao
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, 980-8577, Japan
| | - Hiroki Takahashi
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, 980-8577, Japan
| | - Hideyuki Takahashi
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, 980-8577, Japan
| | - Nobuharu Fujii
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-Ku, Sendai, 980-8577, Japan.
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8
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Ganesh A, Shukla V, Mohapatra A, George AP, Bhukya DPN, Das KK, Kola VSR, Suresh A, Ramireddy E. Root Cap to Soil Interface: A Driving Force Toward Plant Adaptation and Development. PLANT & CELL PHYSIOLOGY 2022; 63:1038-1051. [PMID: 35662353 DOI: 10.1093/pcp/pcac078] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/05/2022] [Accepted: 06/03/2022] [Indexed: 06/15/2023]
Abstract
Land plants have developed robust roots to grow in diverse soil ecosystems. The distal end of the root tip has a specialized organ called the 'root cap'. The root cap assists the roots in penetrating the ground, absorbing water and minerals, avoiding heavy metals and regulating the rhizosphere microbiota. Furthermore, root-cap-derived auxin governs the lateral root patterning and directs root growth under varying soil conditions. The root cap formation is hypothesized as one of the key innovations during root evolution. Morphologically diversified root caps in early land plant lineage and later in angiosperms aid in improving the adaptation of roots and, thereby, plants in diverse soil environments. This review article presents a retrospective view of the root cap's important morphological and physiological characteristics for the root-soil interaction and their response toward various abiotic and biotic stimuli. Recent single-cell RNAseq data shed light on root cap cell-type-enriched genes. We compiled root cap cell-type-enriched genes from Arabidopsis, rice, maize and tomato and analyzed their transcription factor (TF) binding site enrichment. Further, the putative gene regulatory networks derived from root-cap-enriched genes and their TF regulators highlight the species-specific biological functions of root cap genes across the four plant species.
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Affiliation(s)
- Alagarasan Ganesh
- Indian Institute of Science Education and Research (IISER) Tirupati, Biology Division, Tirupati, Andhra Pradesh 517507, India
| | - Vishnu Shukla
- Indian Institute of Science Education and Research (IISER) Tirupati, Biology Division, Tirupati, Andhra Pradesh 517507, India
| | - Ankita Mohapatra
- Indian Institute of Science Education and Research (IISER) Tirupati, Biology Division, Tirupati, Andhra Pradesh 517507, India
| | - Abin Panackal George
- Indian Institute of Science Education and Research (IISER) Tirupati, Biology Division, Tirupati, Andhra Pradesh 517507, India
| | - Durga Prasad Naik Bhukya
- Indian Institute of Science Education and Research (IISER) Tirupati, Biology Division, Tirupati, Andhra Pradesh 517507, India
| | - Krishna Kodappully Das
- Indian Institute of Science Education and Research (IISER) Tirupati, Biology Division, Tirupati, Andhra Pradesh 517507, India
| | - Vijaya Sudhakara Rao Kola
- Indian Institute of Science Education and Research (IISER) Tirupati, Biology Division, Tirupati, Andhra Pradesh 517507, India
| | - Aparna Suresh
- Indian Institute of Science Education and Research (IISER) Tirupati, Biology Division, Tirupati, Andhra Pradesh 517507, India
| | - Eswarayya Ramireddy
- Indian Institute of Science Education and Research (IISER) Tirupati, Biology Division, Tirupati, Andhra Pradesh 517507, India
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9
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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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10
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Li C, Li L, Reynolds MP, Wang J, Chang X, Mao X, Jing R. Recognizing the hidden half in wheat: root system attributes associated with drought tolerance. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:5117-5133. [PMID: 33783492 DOI: 10.1093/jxb/erab124] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/15/2021] [Indexed: 05/09/2023]
Abstract
Improving drought tolerance in wheat is crucial for maintaining productivity and food security. Roots are responsible for the uptake of water from soil, and a number of root traits are associated with drought tolerance. Studies have revealed many quantitative trait loci and genes controlling root development in plants. However, the genetic dissection of root traits in response to drought in wheat is still unclear. Here, we review crop root traits associated with drought, key genes governing root development in plants, and quantitative trait loci and genes regulating root system architecture under water-limited conditions in wheat. Deep roots, optimal root length density and xylem diameter, and increased root surface area are traits contributing to drought tolerance. In view of the diverse environments in which wheat is grown, the balance among root and shoot traits, as well as individual and population performance, are discussed. The known functions of key genes provide information for the genetic dissection of root development of wheat in a wide range of conditions, and will be beneficial for molecular marker development, marker-assisted selection, and genetic improvement in breeding for drought tolerance.
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Affiliation(s)
- Chaonan Li
- National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Long Li
- National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | | | - Jingyi Wang
- National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xiaoping Chang
- National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xinguo Mao
- National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Ruilian Jing
- National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
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11
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Wang Y, Afeworki Y, Geng S, Kanchupati P, Gu M, Martins C, Rude B, Tefera H, Kim Y, Ge X, Auger D, Chen S, Yang P, Hu T, Wu Y. Hydrotropism in the primary roots of maize. THE NEW PHYTOLOGIST 2020; 226:1796-1808. [PMID: 32020611 DOI: 10.1111/nph.16472] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 01/26/2020] [Indexed: 06/10/2023]
Abstract
Recent studies mainly in Arabidopsis have renewed interest and discussion in some of the key issues in hydrotropism of roots, such as the site of water sensing and the involvement of auxin. We examined hydrotropism in maize (Zea mays) primary roots. We determined the site of water sensing along the root using a nonintrusive method. Kinematic analysis was conducted to investigate spatial root elongation during hydrotropic response. Indole-3-acetic acid (IAA) and other hormones were quantified using LC-MS/MS. The transcriptome was analyzed using RNA sequencing. Main results: The very tip of the root is the most sensitive to the hydrostimulant. Hydrotropic bending involves coordinated adjustment of spatial cell elongation and cell flux. IAA redistribution occurred in maize roots, preceding hydrotropic bending. The redistribution is caused by a reduction of IAA content on the side facing a hydrostimulant, resulting in a higher IAA content on the dry side. Transcriptomic analysis of the elongation zone prior to bending identified IAA response and lignin synthesis/wall cross-linking as some of the key processes occurring during the early stages of hydrotropic response. We conclude that maize roots differ from Arabidopsis in the location of hydrostimulant sensing and the involvement of IAA redistribution.
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Affiliation(s)
- Yafang Wang
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, 57007, USA
- College of Grassland Agriculture, Northwest A&F University, 712100, Yangling, China
| | - Yohannes Afeworki
- Department of Mathematics and Statistics, South Dakota State University, Brookings, SD, 57007, USA
| | - Sisi Geng
- Department of Biology, Genetics Institute, Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL, 32610, USA
| | - Praveena Kanchupati
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, 57007, USA
| | - Muyu Gu
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, 57007, USA
| | - Chidi Martins
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, 57007, USA
| | - Brady Rude
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, 57007, USA
| | - Haileselassie Tefera
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, 57007, USA
| | - Yongjun Kim
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, 57007, USA
| | - Xijin Ge
- Department of Mathematics and Statistics, South Dakota State University, Brookings, SD, 57007, USA
| | - Donald Auger
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, 57007, USA
| | - Sixue Chen
- Department of Biology, Genetics Institute, Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL, 32610, USA
| | - Peizhi Yang
- College of Grassland Agriculture, Northwest A&F University, 712100, Yangling, China
| | - Tianming Hu
- College of Grassland Agriculture, Northwest A&F University, 712100, Yangling, China
| | - Yajun Wu
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, 57007, USA
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12
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Miyazawa Y, Takahashi H. Molecular mechanisms mediating root hydrotropism: what we have observed since the rediscovery of hydrotropism. JOURNAL OF PLANT RESEARCH 2020; 133:3-14. [PMID: 31797131 PMCID: PMC7082378 DOI: 10.1007/s10265-019-01153-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 11/19/2019] [Indexed: 06/02/2023]
Abstract
Roots display directional growth toward moisture in response to a water potential gradient. Root hydrotropism is thought to facilitate plant adaptation to continuously changing water availability. Hydrotropism has not been as extensively studied as gravitropism. However, comparisons of hydrotropic and gravitropic responses identified mechanisms that are unique to hydrotropism. Regulatory mechanisms underlying the hydrotropic response appear to differ among different species. We recently performed molecular and genetic analyses of root hydrotropism in Arabidopsis thaliana. In this review, we summarize the current knowledge of specific mechanisms mediating root hydrotropism in several plant species.
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Affiliation(s)
- Yutaka Miyazawa
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata, 990-8560, Japan.
| | - Hideyuki Takahashi
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
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13
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Del Bianco M, Kepinski S. Building a future with root architecture. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:5319-5323. [PMID: 30445468 PMCID: PMC6255693 DOI: 10.1093/jxb/ery390] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Affiliation(s)
- Marta Del Bianco
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Stefan Kepinski
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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14
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Chen Y, Xie Y, Song C, Zheng L, Rong X, Jia L, Luo L, Zhang C, Qu X, Xuan W. A comparison of lateral root patterning among dicot and monocot plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 274:201-211. [PMID: 30080605 DOI: 10.1016/j.plantsci.2018.05.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/18/2018] [Accepted: 05/21/2018] [Indexed: 05/22/2023]
Abstract
Lateral root branching along the primary root involves complex gene regulatory networks in model plant Arabidopsis. However, it is largely unclarified whether different plant species share a common mechanism to pattern the lateral root along the primary axis. In this study, we assessed the development pattern of lateral root among several dicot and monocot plants, including Arabidopsis, tomato, Medicago, Nicotiana, rice, and ryegrass by using an agar-gel culture system. Our results reveal a regular-spaced distribution pattern of lateral roots along the primary root axis of both dicot and monocot plants. Meanwhile, the root patterning is tightly controlled by root bending and the plant hormone auxin. However, nitrogen and phosphate starvations trigger distinguished root growth patterns among different plant species. Our studies strongly suggest a partially shared signaling pathway underlying root patterning of various plant species, and also provide a foundation for further identification of genes associated with root development.
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Affiliation(s)
- Yuqin Chen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Yuanming Xie
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Caihong Song
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Lulu Zheng
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Xiong Rong
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Letian Jia
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Long Luo
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Chi Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Xiaoxiao Qu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, 210095, PR China
| | - Wei Xuan
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, 210095, PR China.
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15
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Dietrich D. Hydrotropism: how roots search for water. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:2759-2771. [PMID: 29529239 DOI: 10.1093/jxb/ery034] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 01/18/2018] [Indexed: 05/25/2023]
Abstract
Fresh water is an increasingly scarce resource for agriculture. Plant roots mediate water uptake from the soil and have developed a number of adaptive traits such as hydrotropism to aid water foraging. Hydrotropism modifies root growth to respond to a water potential gradient in soil and grow towards areas with a higher moisture content. Abscisic acid (ABA) and a small number of genes, including those encoding ABA signal transducers, MIZ2/GNOM, and the hydrotropism-specific MIZ1, are known to be necessary for the response in Arabidopsis thaliana, whereas the role of auxin in hydrotropism appears to vary depending on the plant species. This review will describe recent progress characterizing the hormonal regulation of hydrotropism. Recent advances in identifying the sites of hydrotropic perception and response, together with its interaction with gravitropism, will also be discussed. Finally, I will describe putative mechanisms for perception of the water potential gradient and a potential role for hydrotropism in acclimatizing plants to drought conditions.
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Affiliation(s)
- Daniela Dietrich
- Centre for Plant Integrative Biology and Plant & Crop Sciences, School of Biosciences, University of Nottingham, Nottingham, UK
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16
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Harmer SL, Brooks CJ. Growth-mediated plant movements: hidden in plain sight. CURRENT OPINION IN PLANT BIOLOGY 2018; 41:89-94. [PMID: 29107827 PMCID: PMC5826749 DOI: 10.1016/j.pbi.2017.10.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 10/13/2017] [Accepted: 10/17/2017] [Indexed: 05/18/2023]
Abstract
While fast plant movements are spectacular but rare, almost all plants exhibit relatively slow, growth-mediated tropic movements that are key to their survival in the natural world. In this brief review, we discuss recent insights into the molecular mechanisms underlying phototropism, gravitropism, hydrotropism, and autostraightening. Careful molecular genetic and physiological studies have helped confirm the importance of lateral auxin gradients in gravitropic and phototropic responses. However, auxin signaling does not explain all tropisms: recent work has shown that abscisic acid signaling mediates root hydrotropism and has implicated mechanosensing in autostraightening, the organ straightening process recently modeled as a proprioceptive response. The interactions between distinct tropic signaling pathways and other internal and external sensory processes are also now being untangled.
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Affiliation(s)
- Stacey L Harmer
- Department of Plant Biology, University of California, One Shields Avenue, Davis, CA 95616, USA.
| | - Christopher J Brooks
- Department of Plant Biology, University of California, One Shields Avenue, Davis, CA 95616, USA
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17
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Root-tip-mediated inhibition of hydrotropism is accompanied with the suppression of asymmetric expression of auxin-inducible genes in response to moisture gradients in cucumber roots. PLoS One 2018; 13:e0189827. [PMID: 29324818 PMCID: PMC5764274 DOI: 10.1371/journal.pone.0189827] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 12/01/2017] [Indexed: 11/23/2022] Open
Abstract
In cucumber seedlings, gravitropism interferes with hydrotropism, which results in the nearly complete inhibition of hydrotropism under stationary conditions. However, hydrotropic responses are induced when the gravitropic response in the root is nullified by clinorotation. Columella cells in the root cap sense gravity, which induces the gravitropic response. In this study, we found that removing the root tip induced hydrotropism in cucumber roots under stationary conditions. The application of auxin transport inhibitors to cucumber seedlings under stationary conditions suppressed the hydrotropic response induced by the removal of the root tip. To investigate the expression of genes related to hydrotropism in de-tipped cucumber roots, we conducted transcriptome analysis of gene expression by RNA-Seq using seedlings exhibiting hydrotropic and gravitropic responses. Of the 21 and 45 genes asymmetrically expressed during hydrotropic and gravitropic responses, respectively, five genes were identical. Gene ontology (GO) analysis indicated that the category auxin-inducible genes was significantly enriched among genes that were more highly expressed in the concave side of the root than the convex side during hydrotropic or gravitropic responses. Reverse transcription followed by quantitative polymerase chain reaction (RT-qPCR) analysis revealed that root hydrotropism induced under stationary conditions (by removing the root tip) was accompanied by the asymmetric expression of several auxin-inducible genes. However, intact roots did not exhibit the asymmetric expression patterns of auxin-inducible genes under stationary conditions, even in the presence of a moisture gradient. These results suggest that the root tip inhibits hydrotropism by suppressing the induction of asymmetric auxin distribution. Auxin transport and distribution not mediated by the root tip might play a role in hydrotropism in cucumber roots.
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