1
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Hammes UZ, Pedersen BP. Structure and Function of Auxin Transporters. ANNUAL REVIEW OF PLANT BIOLOGY 2024; 75:185-209. [PMID: 38211951 DOI: 10.1146/annurev-arplant-070523-034109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Auxins, a group of central hormones in plant growth and development, are transported by a diverse range of transporters with distinct biochemical and structural properties. This review summarizes the current knowledge on all known auxin transporters with respect to their biochemical and biophysical properties and the methods used to characterize them. In particular, we focus on the recent advances that were made concerning the PIN-FORMED family of auxin exporters. Insights derived from solving their structures have improved our understanding of the auxin export process, and we discuss the current state of the art on PIN-mediated auxin transport, including the use of biophysical methods to examine their properties. Understanding the mechanisms of auxin transport is crucial for understanding plant growth and development, as well as for the development of more effective strategies for crop production and plant biotechnology.
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Affiliation(s)
- Ulrich Z Hammes
- School of Life Sciences, Plant Systems Biology, Technical University of Munich, Freising, Germany;
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2
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Wexler Y, Schroeder JI, Shkolnik D. Hydrotropism mechanisms and their interplay with gravitropism. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:1732-1746. [PMID: 38394056 DOI: 10.1111/tpj.16683] [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: 11/28/2023] [Revised: 01/29/2024] [Accepted: 02/02/2024] [Indexed: 02/25/2024]
Abstract
Plants partly optimize their water recruitment from the growth medium by directing root growth toward a moisture source, a phenomenon termed hydrotropism. The default mechanism of downward growth, termed gravitropism, often functions to counteract hydrotropism when the water-potential gradient deviates from the gravity vector. This review addresses the identity of the root sites in which hydrotropism-regulating factors function to attenuate gravitropism and the interplay between these various factors. In this context, the function of hormones, including auxin, abscisic acid, and cytokinins, as well as secondary messengers, calcium ions, and reactive oxygen species in the conflict between these two opposing tropisms is discussed. We have assembled the available data on the effects of various chemicals and genetic backgrounds on both gravitropism and hydrotropism, to provide an up-to-date perspective on the interactions that dictate the orientation of root tip growth. We specify the relevant open questions for future research. Broadening our understanding of root mechanisms of water recruitment holds great potential for providing advanced approaches and technologies that can improve crop plant performance under less-than-optimal conditions, in light of predicted frequent and prolonged drought periods due to global climate change.
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Affiliation(s)
- Yonatan Wexler
- Faculty of Life Sciences, School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Julian I Schroeder
- Cell and Developmental Biology Department, School of Biological Sciences, University of California San Diego, La Jolla, California, 92093-0116, USA
| | - Doron Shkolnik
- Faculty of Agriculture, Food and Environment, Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel
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3
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Alrajhi A, Alharbi S, Beecham S, Alotaibi F. Regulation of root growth and elongation in wheat. FRONTIERS IN PLANT SCIENCE 2024; 15:1397337. [PMID: 38835859 PMCID: PMC11148372 DOI: 10.3389/fpls.2024.1397337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 05/06/2024] [Indexed: 06/06/2024]
Abstract
Currently, the control of rhizosphere selection on farms has been applied to achieve enhancements in phenotype, extending from improvements in single root characteristics to the dynamic nature of entire crop systems. Several specific signals, regulatory elements, and mechanisms that regulate the initiation, morphogenesis, and growth of new lateral or adventitious root species have been identified, but much more work remains. Today, phenotyping technology drives the development of root traits. Available models for simulation can support all phenotyping decisions (root trait improvement). The detection and use of markers for quantitative trait loci (QTLs) are effective for enhancing selection efficiency and increasing reproductive genetic gains. Furthermore, QTLs may help wheat breeders select the appropriate roots for efficient nutrient acquisition. Single-nucleotide polymorphisms (SNPs) or alignment of sequences can only be helpful when they are associated with phenotypic variation for root development and elongation. Here, we focus on major root development processes and detail important new insights recently generated regarding the wheat genome. The first part of this review paper discusses the root morphology, apical meristem, transcriptional control, auxin distribution, phenotyping of the root system, and simulation models. In the second part, the molecular genetics of the wheat root system, SNPs, TFs, and QTLs related to root development as well as genome editing (GE) techniques for the improvement of root traits in wheat are discussed. Finally, we address the effect of omics strategies on root biomass production and summarize existing knowledge of the main molecular mechanisms involved in wheat root development and elongation.
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Affiliation(s)
- Abdullah Alrajhi
- King Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi Arabia
- Sustainable Infrastructure and Resource Management, University of South Australia, University of South Australia Science, Technology, Engineering, and Mathematics (UniSA STEM), Mawson Lakes, SA, Australia
| | - Saif Alharbi
- The National Research and Development Center for Sustainable Agriculture (Estidamah), Riyadh, Saudi Arabia
| | - Simon Beecham
- Sustainable Infrastructure and Resource Management, University of South Australia, University of South Australia Science, Technology, Engineering, and Mathematics (UniSA STEM), Mawson Lakes, SA, Australia
| | - Fahad Alotaibi
- King Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi Arabia
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4
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Li Y, Wang L, Chen Y, Zhang J, Xu W. Recovery of root hydrotropism in miz1 mutant by eliminating root gravitropism. JOURNAL OF PLANT PHYSIOLOGY 2024; 292:154144. [PMID: 38104389 DOI: 10.1016/j.jplph.2023.154144] [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: 09/03/2023] [Revised: 11/07/2023] [Accepted: 11/20/2023] [Indexed: 12/19/2023]
Abstract
Mizu-kussei1 (MIZ1) plays a crucial role in root hydrotropism, but it is still unclear whether auxin-mediated gravitropism is involved in MIZ1-modulated root hydrotropism. This study aimed to investigate whether the hydrotropism of the Arabidopsis miz1 mutants could be restored through pharmacological inhibition of auxin transport or genetic modification in root gravitropism. Our findings indicate that the hydrotropic defects of miz1 mutant can be partly recovered by using an auxin transport inhibitor. Furthermore, miz1/pin2 double mutants exhibit more pronounced defects in root gravitropism compared to the wild type, while still displaying a normal hydrotropic response similar to the wild type. These results suggest that the elimination of gravitropism enables miz1 roots to become hydrotropically responsive to moisture gradients.
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Affiliation(s)
- Ying Li
- Jiangsu Key Laboratory of Crop Genomics and Physiology/Jiangsu Key Laboratory of Crop Cultivation and Physiology, Agricultural College of Yangzhou University, Yangzhou, 225009, China; Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China.
| | - Lulu Wang
- Jiangsu Key Laboratory of Crop Genomics and Physiology/Jiangsu Key Laboratory of Crop Cultivation and Physiology, Agricultural College of Yangzhou University, Yangzhou, 225009, China
| | - Yadi Chen
- College of Horticulture and Landscape, Yangzhou University, Yangzhou, 225009, China
| | - Jianhua Zhang
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Weifeng Xu
- Joint International Research Laboratory of Water and Nutrient in Crops, Center for Plant Water-Use and Nutrition Regulation and College of Resource and Environment, Fujian Agriculture and Forestry University, Jinshan, Fuzhou, 350002, China.
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5
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Ung KL, Schulz L, Kleine-Vehn J, Pedersen BP, Hammes UZ. Auxin transport at the endoplasmic reticulum: roles and structural similarity of PIN-FORMED and PIN-LIKES. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:6893-6903. [PMID: 37279330 DOI: 10.1093/jxb/erad192] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 06/02/2023] [Indexed: 06/08/2023]
Abstract
Auxin is a crucial plant hormone that controls a multitude of developmental processes. The directional movement of auxin between cells is largely facilitated by canonical PIN-FORMED proteins in the plasma membrane. In contrast, non-canonical PIN-FORMED proteins and PIN-LIKES proteins appear to reside mainly in the endoplasmic reticulum. Despite recent progress in identifying the roles of the endoplasmic reticulum in cellular auxin responses, the transport dynamics of auxin at the endoplasmic reticulum are not well understood. PIN-LIKES are structurally related to PIN-FORMED proteins, and recently published structures of these transporters have provided new insights into PIN-FORMED proteins and PIN-LIKES function. In this review, we summarize current knowledge on PIN-FORMED proteins and PIN-LIKES in intracellular auxin transport. We discuss the physiological properties of the endoplasmic reticulum and the consequences for transport processes across the ER membrane. Finally, we highlight the emerging role of the endoplasmic reticulum in the dynamics of cellular auxin signalling and its impact on plant development.
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Affiliation(s)
- Kien Lam Ung
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Lukas Schulz
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
| | - Jürgen Kleine-Vehn
- Institute of Biology II, Department of Molecular Plant Physiology (MoPP), University of Freiburg, 79104 Freiburg, Germany
- Center for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, 79104 Freiburg, Germany
| | | | - Ulrich Z Hammes
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
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6
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Xia J, Kong M, Yang Z, Sun L, Peng Y, Mao Y, Wei H, Ying W, Gao Y, Friml J, Weng J, Liu X, Sun L, Tan S. Chemical inhibition of Arabidopsis PIN-FORMED auxin transporters by the anti-inflammatory drug naproxen. PLANT COMMUNICATIONS 2023; 4:100632. [PMID: 37254481 PMCID: PMC10721474 DOI: 10.1016/j.xplc.2023.100632] [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: 03/17/2023] [Revised: 04/12/2023] [Accepted: 05/24/2023] [Indexed: 06/01/2023]
Abstract
The phytohormone auxin plays central roles in many growth and developmental processes in plants. Development of chemical tools targeting the auxin pathway is useful for both plant biology and agriculture. Here we reveal that naproxen, a synthetic compound with anti-inflammatory activity in humans, acts as an auxin transport inhibitor targeting PIN-FORMED (PIN) transporters in plants. Physiological experiments indicate that exogenous naproxen treatment affects pleiotropic auxin-regulated developmental processes. Additional cellular and biochemical evidence indicates that naproxen suppresses auxin transport, specifically PIN-mediated auxin efflux. Moreover, biochemical and structural analyses confirm that naproxen binds directly to PIN1 protein via the same binding cavity as the indole-3-acetic acid substrate. Thus, by combining cellular, biochemical, and structural approaches, this study clearly establishes that naproxen is a PIN inhibitor and elucidates the underlying mechanisms. Further use of this compound may advance our understanding of the molecular mechanisms of PIN-mediated auxin transport and expand our toolkit in auxin biology and agriculture.
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Affiliation(s)
- Jing Xia
- MOE Key Laboratory for Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, The First Affiliated Hospital of USTC, Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Mengjuan Kong
- MOE Key Laboratory for Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, The First Affiliated Hospital of USTC, Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Zhisen Yang
- MOE Key Laboratory for Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, The First Affiliated Hospital of USTC, Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Lianghanxiao Sun
- MOE Key Laboratory for Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, The First Affiliated Hospital of USTC, Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Yakun Peng
- MOE Key Laboratory for Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, The First Affiliated Hospital of USTC, Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Yanbo Mao
- MOE Key Laboratory for Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, The First Affiliated Hospital of USTC, Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Hong Wei
- MOE Key Laboratory for Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, The First Affiliated Hospital of USTC, Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Wei Ying
- MOE Key Laboratory for Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, The First Affiliated Hospital of USTC, Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Yongxiang Gao
- MOE Key Laboratory for Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, The First Affiliated Hospital of USTC, Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Jiří Friml
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Jianping Weng
- MOE Key Laboratory for Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, The First Affiliated Hospital of USTC, Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China.
| | - Xin Liu
- MOE Key Laboratory for Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, The First Affiliated Hospital of USTC, Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China.
| | - Linfeng Sun
- MOE Key Laboratory for Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, The First Affiliated Hospital of USTC, Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China.
| | - Shutang Tan
- MOE Key Laboratory for Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, The First Affiliated Hospital of USTC, Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China; Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China.
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7
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Ung KL, Schulz L, Stokes DL, Hammes UZ, Pedersen BP. Substrate recognition and transport mechanism of the PIN-FORMED auxin exporters. Trends Biochem Sci 2023; 48:937-948. [PMID: 37574372 PMCID: PMC10592131 DOI: 10.1016/j.tibs.2023.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/30/2023] [Accepted: 07/17/2023] [Indexed: 08/15/2023]
Abstract
Auxins are pivotal plant hormones that regulate plant growth and transmembrane polar auxin transport (PAT) direct patterns of development. The PIN-FORMED (PIN) family of membrane transporters mediate auxin export from the plant cell and play crucial roles in PAT. Here we describe the recently solved structures of PIN transporters, PIN1, PIN3, and PIN8, and also their mechanisms of substrate recognition and transport of auxin. We compare structures of PINs in both inward- and outward-facing conformations, as well as PINs with different binding configurations for auxin. By this comparative analysis, a model emerges for an elevator transport mechanism. Central structural elements necessary for function are identified, and we show that these are shared with other distantly related protein families.
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Affiliation(s)
- Kien Lam Ung
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Lukas Schulz
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
| | - David L Stokes
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, NY 10016, USA
| | - Ulrich Z Hammes
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
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8
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Thomas M, Soriano A, O'Connor C, Crabos A, Nacry P, Thompson M, Hrabak E, Divol F, Péret B. pin2 mutant agravitropic root phenotype is conditional and nutrient-sensitive. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 329:111606. [PMID: 36706868 DOI: 10.1016/j.plantsci.2023.111606] [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: 09/29/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 06/18/2023]
Abstract
Plants have the capacity to sense and adapt to environmental factors using the phytohormone auxin as a major regulator of tropism and development. Among these responses, gravitropism is essential for plant roots to grow downward in the search for nutrients and water. We discovered a new mutant allele of the auxin efflux transporter PIN2 that revealed that pin2 agravitropic root mutants are conditional and nutrient-sensitive. We describe that nutrient composition of the medium, rather than osmolarity, can revert the agravitropic root phenotype of pin2. Indeed, on phosphorus- and nitrogen-deprived media, the agravitropic root defect was restored independently of primary root growth levels. Slow and fast auxin responses were evaluated using DR5 and R2D2 probes, respectively, and revealed a strong modulation by nutrient composition of the culture medium. We evaluated the role of PIN and AUX auxin transporters and demonstrated that neither PIN3 nor AUX1 are involved in this process. However, we observed the ectopic expression of PIN1 in the epidermis in the pin2 mutant background associated with permissive, but not restrictive, conditions. This ectopic expression was associated with a restoration of the asymmetric accumulation of auxin necessary for the reorientation of the root according to gravity. These observations suggest a strong regulation of auxin distribution by nutrients availability, directly impacting root's ability to drive their gravitropic response.
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Affiliation(s)
- Marion Thomas
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Alexandre Soriano
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Claire O'Connor
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Amandine Crabos
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Philippe Nacry
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | | | | | - Fanchon Divol
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Benjamin Péret
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France.
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9
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Carrillo‐Carrasco VP, Hernandez‐Garcia J, Mutte SK, Weijers D. The birth of a giant: evolutionary insights into the origin of auxin responses in plants. EMBO J 2023; 42:e113018. [PMID: 36786017 PMCID: PMC10015382 DOI: 10.15252/embj.2022113018] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/20/2023] [Accepted: 01/25/2023] [Indexed: 02/15/2023] Open
Abstract
The plant signaling molecule auxin is present in multiple kingdoms of life. Since its discovery, a century of research has been focused on its action as a phytohormone. In land plants, auxin regulates growth and development through transcriptional and non-transcriptional programs. Some of the molecular mechanisms underlying these responses are well understood, mainly in Arabidopsis. Recently, the availability of genomic and transcriptomic data of green lineages, together with phylogenetic inference, has provided the basis to reconstruct the evolutionary history of some components involved in auxin biology. In this review, we follow the evolutionary trajectory that allowed auxin to become the "giant" of plant biology by focusing on bryophytes and streptophyte algae. We consider auxin biosynthesis, transport, physiological, and molecular responses, as well as evidence supporting the role of auxin as a chemical messenger for communication within ecosystems. Finally, we emphasize that functional validation of predicted orthologs will shed light on the conserved properties of auxin biology among streptophytes.
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Affiliation(s)
| | | | - Sumanth K Mutte
- Laboratory of BiochemistryWageningen UniversityWageningenthe Netherlands
| | - Dolf Weijers
- Laboratory of BiochemistryWageningen UniversityWageningenthe Netherlands
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10
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Su SH, Moen A, Groskopf RM, Baldwin KL, Vesperman B, Masson PH. Low-Speed Clinorotation of Brachypodium distachyon and Arabidopsis thaliana Seedlings Triggers Root Tip Curvatures That Are Reminiscent of Gravitropism. Int J Mol Sci 2023; 24:1540. [PMID: 36675054 PMCID: PMC9861679 DOI: 10.3390/ijms24021540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/28/2022] [Accepted: 01/09/2023] [Indexed: 01/15/2023] Open
Abstract
Clinostats are instruments that continuously rotate biological specimens along an axis, thereby averaging their orientation relative to gravity over time. Our previous experiments indicated that low-speed clinorotation may itself trigger directional root tip curvature. In this project, we have investigated the root curvature response to low-speed clinorotation using Arabidopsis thaliana and Brachypodium distachyon seedlings as models. We show that low-speed clinorotation triggers root tip curvature in which direction is dictated by gravitropism during the first half-turn of clinorotation. We also show that the angle of root tip curvature is modulated by the speed of clinorotation. Arabidopsis mutations affecting gravity susception (pgm) or gravity signal transduction (arg1, toc132) are shown to affect the root tip curvature response to low-speed clinorotation. Furthermore, low-speed vertical clinorotation triggers relocalization of the PIN3 auxin efflux facilitator to the lateral membrane of Arabidopsis root cap statocytes, and creates a lateral gradient of auxin across the root tip. Together, these observations support a role for gravitropism in modulating root curvature responses to clinorotation. Interestingly, distinct Brachypodium distachyon accessions display different abilities to develop root tip curvature responses to low-speed vertical clinorotation, suggesting the possibility of using genome-wide association studies to further investigate this process.
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Affiliation(s)
- Shih-Heng Su
- Laboratory of Genetics, University of Wisconsin-Madison, 425 Henry Mall, Madison, WI 53706, USA
| | - Alexander Moen
- Laboratory of Genetics, University of Wisconsin-Madison, 425 Henry Mall, Madison, WI 53706, USA
| | - Rien M. Groskopf
- Laboratory of Genetics, University of Wisconsin-Madison, 425 Henry Mall, Madison, WI 53706, USA
| | | | - Brian Vesperman
- Kate Baldwin LLC, Analytical Design, Cross Plains, WI 53528, USA
| | - Patrick H. Masson
- Laboratory of Genetics, University of Wisconsin-Madison, 425 Henry Mall, Madison, WI 53706, USA
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11
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Yang Y, Liu F, Liu L, Zhu M, Yuan J, Mai YX, Zou JJ, Le J, Wang Y, Palme K, Li X, Wang Y, Wang L. The unconventional prefoldin RPB5 interactor mediates the gravitropic response by modulating cytoskeleton organization and auxin transport in Arabidopsis. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:1916-1934. [PMID: 35943836 DOI: 10.1111/jipb.13341] [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: 05/23/2022] [Accepted: 08/08/2022] [Indexed: 06/15/2023]
Abstract
Gravity-induced root curvature involves the asymmetric distribution of the phytohormone auxin. This response depends on the concerted activities of the auxin transporters such as PIN-FORMED (PIN) proteins for auxin efflux and AUXIN RESISTANT 1 (AUX1) for auxin influx. However, how the auxin gradient is established remains elusive. Here we identified a new mutant with a short root, strong auxin distribution in the lateral root cap and an impaired gravitropic response. The causal gene encoded an Arabidopsis homolog of the human unconventional prefoldin RPB5 interactor (URI). AtURI interacted with prefoldin 2 (PFD2) and PFD6, two β-type PFD members that modulate actin and tubulin patterning in roots. The auxin reporter DR5rev :GFP showed that asymmetric auxin redistribution after gravistimulation is disordered in aturi-1 root tips. Treatment with the endomembrane protein trafficking inhibitor brefeldin A indicated that recycling of the auxin transporter PIN2 is disrupted in aturi-1 roots as well as in pfd mutants. We propose that AtURI cooperates with PFDs to recycle PIN2 and modulate auxin distribution.
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Affiliation(s)
- Yi Yang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Daizong Street 61, Tai'an, 271018, China
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou, 253023, China
- Sino-German Joint Research Center on Agricultural Biology, College of Life Sciences, Shandong Agricultural University, Daizong Street 61, Tai'an, 271018, China
| | - Fang Liu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Daizong Street 61, Tai'an, 271018, China
- Faculty of Biology, Institute of Biology II/Molecular Plant Physiology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, Freiburg, D-79104, Germany
| | - Le Liu
- Faculty of Biology, Institute of Biology II/Molecular Plant Physiology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, Freiburg, D-79104, Germany
| | - Mingyue Zhu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Daizong Street 61, Tai'an, 271018, China
- Sino-German Joint Research Center on Agricultural Biology, College of Life Sciences, Shandong Agricultural University, Daizong Street 61, Tai'an, 271018, China
| | - Jinfeng Yuan
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Daizong Street 61, Tai'an, 271018, China
- Sino-German Joint Research Center on Agricultural Biology, College of Life Sciences, Shandong Agricultural University, Daizong Street 61, Tai'an, 271018, China
| | - Yan-Xia Mai
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences (CAS), Shanghai, 200032, China
| | - Jun-Jie Zou
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Jie Le
- Key Laboratory of Plant Molecular Physiology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yonghong Wang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Daizong Street 61, Tai'an, 271018, China
| | - Klaus Palme
- Sino-German Joint Research Center on Agricultural Biology, College of Life Sciences, Shandong Agricultural University, Daizong Street 61, Tai'an, 271018, China
- Faculty of Biology, Institute of Biology II/Molecular Plant Physiology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, Freiburg, D-79104, Germany
| | - Xugang Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Daizong Street 61, Tai'an, 271018, China
- Sino-German Joint Research Center on Agricultural Biology, College of Life Sciences, Shandong Agricultural University, Daizong Street 61, Tai'an, 271018, China
| | - Yong Wang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Daizong Street 61, Tai'an, 271018, China
| | - Long Wang
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences (CAS), Shanghai, 200032, China
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12
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Hsieh YH, Wei YH, Lo JC, Pan HY, Yang SY. Arbuscular mycorrhizal symbiosis enhances tomato lateral root formation by modulating CEP2 peptide expression. THE NEW PHYTOLOGIST 2022; 235:292-305. [PMID: 35358343 DOI: 10.1111/nph.18128] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 03/10/2022] [Indexed: 06/14/2023]
Abstract
Plant lateral root (LR) growth usually is stimulated by arbuscular mycorrhizal (AM) symbiosis. However, the molecular mechanism is still unclear. We used gene expression analysis, peptide treatment and virus-induced gene alteration assays to demonstrate that C-terminally encoded peptide (CEP2) expression in tomato was downregulated during AM symbiosis to mitigate its negative effect on LR formation through an auxin-related pathway. We showed that enhanced LR density and downregulated CEP2 expression were observed during mycorrhizal symbiosis. Synthetic CEP2 peptide treatment reduced LR density and impaired the expression of genes involved in indole-3-butyric acid (IBA, the precursor of IAA) to IAA conversion, auxin polar transport and the LR-related signaling pathway; however, application of IBA or synthetic auxin 1-naphthaleneacetic acid (NAA) to the roots may rescue both defective LR formation and reduced gene expression. CEP receptor 1 (CEPR1) might be the receptor of CEP2 because its knockdown plants did not respond to CEP2 treatment. Most importantly, the LR density of CEP2 overexpression or knockdown plants could not be further increased by AM inoculation, suggesting that CEP2 was critical for AM-induced LR formation. These results indicated that AM symbiosis may regulate root development by modulating CEP2, which affects the auxin-related pathway.
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Affiliation(s)
- Yu-Heng Hsieh
- Institute of Plant Biology, Department of Life Science, National Taiwan University, Taipei, 10617, Taiwan
| | - Yi-Hsien Wei
- Institute of Plant Biology, Department of Life Science, National Taiwan University, Taipei, 10617, Taiwan
| | - Jui-Chi Lo
- Institute of Plant Biology, Department of Life Science, National Taiwan University, Taipei, 10617, Taiwan
| | - Hsuan-Yu Pan
- Institute of Plant Biology, Department of Life Science, National Taiwan University, Taipei, 10617, Taiwan
| | - Shu-Yi Yang
- Institute of Plant Biology, Department of Life Science, National Taiwan University, Taipei, 10617, Taiwan
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13
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Zhang F, Li C, Qu X, Liu J, Yu Z, Wang J, Zhu J, Yu Y, Ding Z. A feedback regulation between ARF7-mediated auxin signaling and auxin homeostasis involving MES17 affects plant gravitropism. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:1339-1351. [PMID: 35475598 DOI: 10.1111/jipb.13268] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Accepted: 04/25/2022] [Indexed: 06/14/2023]
Abstract
Gravitropism is an essential adaptive response of land plants. Asymmetric auxin gradients across plant organs, interpreted by multiple auxin signaling components including AUXIN RESPONSE FACTOR7 (ARF7), trigger differential growth and bending response. However, how this fundamental process is strictly maintained in nature remains unclear. Here, we report that gravity stimulates the transcription of METHYL ESTERASE17 (MES17) along the lower side of the hypocotyl via ARF7-dependent auxin signaling. The asymmetric distribution of MES17, a methyltransferase that converts auxin from its inactive form methyl indole-3-acetic acid ester (MeIAA) to its biologically active form free-IAA, enhanced the gradient of active auxin across the hypocotyl, which in turn reversely amplified the asymmetric auxin responses and differential growth that shape gravitropic bending. Taken together, our findings reveal the novel role of MES17-mediated auxin homeostasis in gravitropic responses and identify an ARF7-triggered feedback mechanism that reinforces the asymmetric distribution of active auxin and strictly controls gravitropism in plants.
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Affiliation(s)
- Feng Zhang
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Cuiling Li
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Xingzhen Qu
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Jiajia Liu
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Zipeng Yu
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Junxia Wang
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Jiayong Zhu
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Yongqiang Yu
- Horticulture Biology and Metabolomics Center, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Zhaojun Ding
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao, 266237, China
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14
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Ung KL, Winkler M, Schulz L, Kolb M, Janacek DP, Dedic E, Stokes DL, Hammes UZ, Pedersen BP. Structures and mechanism of the plant PIN-FORMED auxin transporter. Nature 2022; 609:605-610. [PMID: 35768502 PMCID: PMC9477730 DOI: 10.1038/s41586-022-04883-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 05/19/2022] [Indexed: 11/15/2022]
Abstract
Auxins are hormones that have central roles and control nearly all aspects of growth and development in plants1–3. The proteins in the PIN-FORMED (PIN) family (also known as the auxin efflux carrier family) are key participants in this process and control auxin export from the cytosol to the extracellular space4–9. Owing to a lack of structural and biochemical data, the molecular mechanism of PIN-mediated auxin transport is not understood. Here we present biophysical analysis together with three structures of Arabidopsis thaliana PIN8: two outward-facing conformations with and without auxin, and one inward-facing conformation bound to the herbicide naphthylphthalamic acid. The structure forms a homodimer, with each monomer divided into a transport and scaffold domain with a clearly defined auxin binding site. Next to the binding site, a proline–proline crossover is a pivot point for structural changes associated with transport, which we show to be independent of proton and ion gradients and probably driven by the negative charge of the auxin. The structures and biochemical data reveal an elevator-type transport mechanism reminiscent of bile acid/sodium symporters, bicarbonate/sodium symporters and sodium/proton antiporters. Our results provide a comprehensive molecular model for auxin recognition and transport by PINs, link and expand on a well-known conceptual framework for transport, and explain a central mechanism of polar auxin transport, a core feature of plant physiology, growth and development. Structural and biophysical analysis of the Arabidopsis thaliana auxin transporter PIN8 reveal that PIN transporters export auxin using an elevator mechanism.
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Affiliation(s)
- Kien Lam Ung
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Mikael Winkler
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Lukas Schulz
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Martina Kolb
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Dorina P Janacek
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Emil Dedic
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - David L Stokes
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, New York University School of Medicine, New York, NY, USA
| | - Ulrich Z Hammes
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.
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15
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Chen P, Ge Y, Chen L, Yan F, Cai L, Zhao H, Lei D, Jiang J, Wang M, Tao Y. SAV4 is required for ethylene-induced root hair growth through stabilizing PIN2 auxin transporter in Arabidopsis. THE NEW PHYTOLOGIST 2022; 234:1735-1752. [PMID: 35274300 DOI: 10.1111/nph.18079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 02/27/2022] [Indexed: 06/14/2023]
Abstract
Root hair development is regulated by hormonal and environmental cues, such as ethylene and low phosphate. Auxin efflux carrier PIN2 (PIN-FORMED 2) plays an important role in establishing a proper auxin gradient in root tips, which is required for root hair development. Ethylene promotes root hair development through increasing PIN2 abundance in root tips, which subsequently leads to enhanced expression of auxin reporter genes. However, how PIN2 is regulated remains obscure. Here, we report that Arabidopsis thaliana sav4 (shade avoidance 4) mutant exhibits defects in ethylene-induced root hair development and in establishing a proper auxin gradient in root tips. Ethylene treatment increased SAV4 abundance in root tips. SAV4 and PIN2 co-localize to the shootward plasma membrane (PM) of root tip epidermal cells. SAV4 directly interacts with the PIN2 hydrophilic region (PIN2HL) and regulates PIN2 abundance on the PM. Vacuolar degradation of PIN2 is suppressed by ethylene, which was weakened in sav4 mutant. Furthermore, SAV4 affects the formation of PIN2 clusters and its lateral diffusion on the PM. In summary, we identified SAV4 as a novel regulator of PIN2 that enhances PIN2 membrane clustering and stability through direct protein-protein interactions. Our study revealed a new layer of regulation on PIN2 dynamics.
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Affiliation(s)
- Peirui Chen
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiang'an South Road, Xiamen, Fujian Province, 361102, China
| | - Yanhua Ge
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiang'an South Road, Xiamen, Fujian Province, 361102, China
| | - Liying Chen
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiang'an South Road, Xiamen, Fujian Province, 361102, China
| | - Fenglian Yan
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiang'an South Road, Xiamen, Fujian Province, 361102, China
| | - Lingling Cai
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiang'an South Road, Xiamen, Fujian Province, 361102, China
| | - Hongli Zhao
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiang'an South Road, Xiamen, Fujian Province, 361102, China
| | - Deshun Lei
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiang'an South Road, Xiamen, Fujian Province, 361102, China
| | - Jinxi Jiang
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiang'an South Road, Xiamen, Fujian Province, 361102, China
| | - Meiling Wang
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiang'an South Road, Xiamen, Fujian Province, 361102, China
| | - Yi Tao
- School of Life Sciences, Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiang'an South Road, Xiamen, Fujian Province, 361102, China
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16
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Mellor NL, Voß U, Ware A, Janes G, Barrack D, Bishopp A, Bennett MJ, Geisler M, Wells DM, Band LR. Systems approaches reveal that ABCB and PIN proteins mediate co-dependent auxin efflux. THE PLANT CELL 2022; 34:2309-2327. [PMID: 35302640 PMCID: PMC9134068 DOI: 10.1093/plcell/koac086] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 03/10/2022] [Indexed: 05/11/2023]
Abstract
Members of the B family of membrane-bound ATP-binding cassette (ABC) transporters represent key components of the auxin efflux machinery in plants. Over the last two decades, experimental studies have shown that modifying ATP-binding cassette sub-family B (ABCB) expression affects auxin distribution and plant phenotypes. However, precisely how ABCB proteins transport auxin in conjunction with the more widely studied family of PIN-formed (PIN) auxin efflux transporters is unclear, and studies using heterologous systems have produced conflicting results. Here, we integrate ABCB localization data into a multicellular model of auxin transport in the Arabidopsis thaliana root tip to predict how ABCB-mediated auxin transport impacts organ-scale auxin distribution. We use our model to test five potential ABCB-PIN regulatory interactions, simulating the auxin dynamics for each interaction and quantitatively comparing the predictions with experimental images of the DII-VENUS auxin reporter in wild-type and abcb single and double loss-of-function mutants. Only specific ABCB-PIN regulatory interactions result in predictions that recreate the experimentally observed DII-VENUS distributions and long-distance auxin transport. Our results suggest that ABCBs enable auxin efflux independently of PINs; however, PIN-mediated auxin efflux is predominantly through a co-dependent efflux where co-localized with ABCBs.
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Affiliation(s)
| | | | - Alexander Ware
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - George Janes
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Duncan Barrack
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Anthony Bishopp
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Malcolm J Bennett
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Markus Geisler
- Department of Biology, University of Fribourg, Fribourg CH-1700, Switzerland
| | - Darren M Wells
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
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17
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PIN3 from Liriodendron May Function in Inflorescence Development and Root Elongation. FORESTS 2022. [DOI: 10.3390/f13040568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Auxin, the first discovered phytohormone, is important for the growth and development of plants through the establishment of homeostasis and asymmetry. Here, we cloned the auxin transporter gene PIN-FORMED3 (PIN3) from the valuable timber tree hybrid Liriodendron (Liriodendron chinense × Liriodendron tulipifera). The gene contained a complete open reading frame of 1917 bp that encoded 638 amino acids. Phylogenetic analysis indicated that LhPIN3 exhibited the highest sequence similarity to the PIN3 of Vitis vinifera. Quantitative real-time PCR analysis showed that LhPIN3 was broadly expressed across different tissues/organs of Liriodendron, with the highest expression level in the roots. Heterologous overexpression of LhPIN3 in Arabidopsis thaliana caused considerable phenotypic changes, such as the root length and number of flowers. Genetic complementation of Arabidopsis pin1 mutants by LhPIN3, driven by the cauliflower mosaic virus 35S promoter, fully restored the root length and number of flowers of the pin1 mutant. Overall, our findings reveal that LhPIN3 has similar capacities to regulate the root length and number of flowers of Arabidopsis with AtPIN1.
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18
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Ma X, Zhao X, Zhang H, Zhang Y, Sun S, Li Y, Long Z, Liu Y, Zhang X, Li R, Tan L, Jiang L, Zhu JK, Li L. MAG2 and MAL Regulate Vesicle Trafficking and Auxin Homeostasis With Functional Redundancy. FRONTIERS IN PLANT SCIENCE 2022; 13:849532. [PMID: 35371137 PMCID: PMC8966843 DOI: 10.3389/fpls.2022.849532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
Auxin is a central phytohormone and controls almost all aspects of plant development and stress response. Auxin homeostasis is coordinately regulated by biosynthesis, catabolism, transport, conjugation, and deposition. Endoplasmic reticulum (ER)-localized MAIGO2 (MAG2) complex mediates tethering of arriving vesicles to the ER membrane, and it is crucial for ER export trafficking. Despite important regulatory roles of MAG2 in vesicle trafficking, the mag2 mutant had mild developmental abnormalities. MAG2 has one homolog protein, MAG2-Like (MAL), and the mal-1 mutant also had slight developmental phenotypes. In order to investigate MAG2 and MAL regulatory function in plant development, we generated the mag2-1 mal-1 double mutant. As expected, the double mutant exhibited serious developmental defects and more alteration in stress response compared with single mutants and wild type. Proteomic analysis revealed that signaling, metabolism, and stress response in mag2-1 mal-1 were affected, especially membrane trafficking and auxin biosynthesis, signaling, and transport. Biochemical and cell biological analysis indicated that the mag2-1 mal-1 double mutant had more serious defects in vesicle transport than the mag2-1 and mal-1 single mutants. The auxin distribution and abundance of auxin transporters were altered significantly in the mag2-1 and mal-1 single mutants and mag2-1 mal-1 double mutant. Our findings suggest that MAG2 and MAL regulate plant development and auxin homeostasis by controlling membrane trafficking, with functional redundancy.
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Affiliation(s)
- Xiaohui Ma
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Xiaonan Zhao
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Hailong Zhang
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Yiming Zhang
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Shanwen Sun
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Ying Li
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Zhengbiao Long
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Yuqi Liu
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Xiaomeng Zhang
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Rongxia Li
- Shanghai Center for Plant Stress Biology, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Li Tan
- Shanghai Center for Plant Stress Biology, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lixi Jiang
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Jian-Kang Zhu
- Shanghai Center for Plant Stress Biology, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lixin Li
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
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19
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Tissue specificity and responses to abiotic stresses and hormones of PIN genes in rice. Biologia (Bratisl) 2022. [DOI: 10.1007/s11756-022-01031-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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20
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Salvalaio M, Oliver N, Tiknaz D, Schwarze M, Kral N, Kim SJ, Sena G. Root electrotropism in Arabidopsis does not depend on auxin distribution but requires cytokinin biosynthesis. PLANT PHYSIOLOGY 2022; 188:1604-1616. [PMID: 34893912 PMCID: PMC8896602 DOI: 10.1093/plphys/kiab587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/16/2021] [Indexed: 06/14/2023]
Abstract
Efficient foraging by plant roots relies on the ability to sense multiple physical and chemical cues in soil and to reorient growth accordingly (tropism). Root tropisms range from sensing gravity (gravitropism), light (phototropism), water (hydrotropism), touch (thigmotropism), and more. Electrotropism, also known as galvanotropism, is the phenomenon of aligning growth with external electric fields and currents. Although root electrotropism has been observed in a few species since the end of the 19th century, its molecular and physical mechanisms remain elusive, limiting its comparison with the more well-defined sensing pathways in plants. Here, we provide a quantitative and molecular characterization of root electrotropism in the model system Arabidopsis (Arabidopsis thaliana), showing that it does not depend on an asymmetric distribution of the plant hormone auxin, but instead requires the biosynthesis of a second hormone, cytokinin. We also show that the dose-response kinetics of the early steps of root electrotropism follows a power law analogous to the one observed in some physiological reactions in animals. Future studies involving more extensive molecular and quantitative characterization of root electrotropism would represent a step toward a better understanding of signal integration in plants and would also serve as an independent outgroup for comparative analysis of electroreception in animals and fungi.
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Affiliation(s)
| | - Nicholas Oliver
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Deniz Tiknaz
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | | | - Nicolas Kral
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Soo-Jeong Kim
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Giovanni Sena
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
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21
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Bogaert KA, Blomme J, Beeckman T, De Clerck O. Auxin's origin: do PILS hold the key? TRENDS IN PLANT SCIENCE 2022; 27:227-236. [PMID: 34716098 DOI: 10.1016/j.tplants.2021.09.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 08/23/2021] [Accepted: 09/28/2021] [Indexed: 05/12/2023]
Abstract
Auxin is a key regulator of many developmental processes in land plants and plays a strikingly similar role in the phylogenetically distant brown seaweeds. Emerging evidence shows that the PIN and PIN-like (PILS) auxin transporter families have preceded the evolution of the canonical auxin response pathway. A wide conservation of PILS-mediated auxin transport, together with reports of auxin function in unicellular algae, would suggest that auxin function preceded the advent of multicellularity. We find that PIN and PILS transporters form two eukaryotic subfamilies within a larger bacterial family. We argue that future functional characterisation of algal PIN and PILS transporters can shed light on a common origin of an auxin function followed by independent co-option in a multicellular context.
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Affiliation(s)
- Kenny Arthur Bogaert
- Department of Biology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent, Belgium.
| | - Jonas Blomme
- Department of Biology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB-UGent, Technologiepark 72, B-9052 Ghent, Belgium
| | - Tom Beeckman
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB-UGent, Technologiepark 72, B-9052 Ghent, Belgium
| | - Olivier De Clerck
- Department of Biology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent, Belgium
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22
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Deslauriers SD, Spalding EP. Electrophysiological study of Arabidopsis ABCB4 and PIN2 auxin transporters: Evidence of auxin activation and interaction enhancing auxin selectivity. PLANT DIRECT 2021; 5:e361. [PMID: 34816076 PMCID: PMC8595762 DOI: 10.1002/pld3.361] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 10/21/2021] [Indexed: 05/25/2023]
Abstract
Polar auxin transport through plant tissue strictly requires polarly localized PIN proteins and uniformly distributed ABCB proteins. A functional synergy between the two types of membrane protein where their localizations overlap may create the degree of asymmetric auxin efflux required to produce polar auxin transport. We investigated this possibility by expressing ABCB4 and PIN2 in human embryonic kidney cells and measuring whole-cell ionic currents with the patch-clamp technique and CsCl-based electrolytes. ABCB4 activity was 1.81-fold more selective for Cl- over Cs+ and for PIN2 the value was 2.95. We imposed auxin gradients and determined that ABCB4 and PIN2 were 12-fold more permeable to the auxin anion (IAA-) than Cl-. This measure of the intrinsic selectivity of the transport pathway was 21-fold when ABCB4 and PIN2 were co-expressed. If this increase occurs in plants, it could explain why asymmetric PIN localization is not sufficient to create polar auxin flow. Some form of co-action or synergy between ABCB4 and PIN2 that increases IAA- selectivity at the cell face where both occur may be important. We also found that auxin stimulated ABCB4 activity, which may contribute to a self-reinforcement of auxin transport known as canalization.
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Affiliation(s)
- Stephen D. Deslauriers
- Department of BotanyUniversity of Wisconsin‐MadisonMadisonWIUSA
- Present address:
Division of Science and MathUniversity of MinnesotaMorrisMNUSA
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23
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The Diversity of Culture-Dependent Gram-Negative Rhizobacteria Associated with Manihot esculenta Crantz Plants Subjected to Water-Deficit Stress. DIVERSITY 2021. [DOI: 10.3390/d13080366] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
There is a lack of studies on the root-associated bacterial microbiome of cassava plants. The identification and characterization of rhizobacteria can contribute to understanding the adaptation of the agriculturally important crop plants to abiotic stress. Rhizobacteria play a significant role in plants, as they can alleviate the drought stress by various mechanisms that enhance the plant growth under these stressor conditions. In this study, Gram-negative bacterial strains from the plant rhizosphere of cassava Manihot esculenta Crantz CIAT MCOL1734 variety subjected to water deprivation were isolated, characterized according to their morphological properties, and then identified by VITEK® 2. An increase in the diversity, abundance, and species richness of Gram-negative rhizobacterial community was found in cassava plants subjected to water-deficit stress. In total, 58 rhizobacterial strains were isolated from cassava plants. The identification process found that the bacteria belonged to 12 genera: Achromobacter, Acinetobacter, Aeromonas, Buttiauxella, Cronobacter, Klebsiella, Ochrobactrum, Pluralibacter, Pseudomonas, Rhizobium, Serratia, and Sphingomonas. Interestingly, Pseudomonas luteola and Ocrhobactrum anthropi were rhizobacteria isolated exclusively from plants submitted to drought conditions. The cassava roots constitute a great reservoir of Gram-negative bacteria with a remarkable potential for biotechnological application to improve the drought tolerance of plant crops under water-deficit conditions.
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Konstantinova N, Korbei B, Luschnig C. Auxin and Root Gravitropism: Addressing Basic Cellular Processes by Exploiting a Defined Growth Response. Int J Mol Sci 2021; 22:2749. [PMID: 33803128 PMCID: PMC7963156 DOI: 10.3390/ijms22052749] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/04/2021] [Accepted: 03/06/2021] [Indexed: 12/14/2022] Open
Abstract
Root architecture and growth are decisive for crop performance and yield, and thus a highly topical research field in plant sciences. The root system of the model plant Arabidopsis thaliana is the ideal system to obtain insights into fundamental key parameters and molecular players involved in underlying regulatory circuits of root growth, particularly in responses to environmental stimuli. Root gravitropism, directional growth along the gravity, in particular represents a highly sensitive readout, suitable to study adjustments in polar auxin transport and to identify molecular determinants involved. This review strives to summarize and give an overview into the function of PIN-FORMED auxin transport proteins, emphasizing on their sorting and polarity control. As there already is an abundance of information, the focus lies in integrating this wealth of information on mechanisms and pathways. This overview of a highly dynamic and complex field highlights recent developments in understanding the role of auxin in higher plants. Specifically, it exemplifies, how analysis of a single, defined growth response contributes to our understanding of basic cellular processes in general.
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Affiliation(s)
| | | | - Christian Luschnig
- Department of Applied Genetics and Cell Biology, Institute of Molecular Plant Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, 1190 Wien, Austria; (N.K.); (B.K.)
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Comprehensive Analysis and Expression Profiling of PIN, AUX/LAX, and ABCB Auxin Transporter Gene Families in Solanum tuberosum under Phytohormone Stimuli and Abiotic Stresses. BIOLOGY 2021; 10:biology10020127. [PMID: 33562678 PMCID: PMC7915614 DOI: 10.3390/biology10020127] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary In this study, we provide comprehensive information on auxin transporter gene families in potato, including basic parameters, chromosomal distribution, phylogeny, co-expression network analysis, gene structure, tissue-specific expression patterns, subcellular localization, transcription analysis under exogenous hormone stimuli and abiotic stresses, and cis-regulatory element prediction. The responsiveness of auxin transporter family genes to auxin and polar auxin transport inhibitors implied their possible roles in auxin homoeostasis and redistribution. Additionally, the differential expression levels of auxin transporter family genes in response to abscisic acid and abiotic stresses suggested their specific adaptive mechanisms on tolerance to various environmental stimuli. Promoter cis-regulatory element description analyses indicated that a number of cis-regulatory elements within the promoters of auxin transporter genes in potato were targeted by relevant transcription factors to respond to diverse stresses. We are confident that our results provide a foundation for a better understanding of auxin transporters in potato, as we have demonstrated the biological significance of this family of genes in hormone signaling and adaption to environmental stresses. Abstract Auxin is the only plant hormone that exhibits transport polarity mediated by three families: auxin resistant (AUX) 1/like AUX1 (LAX) influx carriers, pin-formed (PIN) efflux carriers, and ATP-binding cassette B (ABCB) influx/efflux carriers. Extensive studies about the biological functions of auxin transporter genes have been reported in model plants. Information regarding these genes in potato remains scarce. Here, we conducted a comprehensive analysis of auxin transporter gene families in potato to examine genomic distributions, phylogeny, co-expression analysis, gene structure and subcellular localization, and expression profiling using bioinformatics tools and qRT-PCR analysis. From these analyses, 5 StLAXs, 10 StPINs, and 22 StABCBs were identified in the potato genome and distributed in 10 of 18 gene modules correlating to the development of various tissues. Transient expression experiments indicated that three representative auxin transporters showed plasma membrane localizations. The responsiveness to auxin and auxin transport inhibitors implied their possible roles in mediating intercellular auxin homoeostasis and redistribution. The differential expression under abscisic acid and abiotic stresses indicated their specific adaptive mechanisms regulating tolerance to environmental stimuli. A large number of auxin-responsive and stress-related cis-elements within their promoters could account for their responsiveness to diverse stresses. Our study aimed to understand the biological significance of potato auxin transporters in hormone signaling and tolerance to environmental stresses.
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Xie Q, Essemine J, Pang X, Chen H, Jin J, Cai W. Abscisic Acid Regulates the Root Growth Trajectory by Reducing Auxin Transporter PIN2 Protein Levels in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2021; 12:632676. [PMID: 33763094 PMCID: PMC7982918 DOI: 10.3389/fpls.2021.632676] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 02/15/2021] [Indexed: 05/03/2023]
Abstract
The root is in direct contact with soil. Modulation of root growth in response to alterations in soil conditions is pivotal for plant adaptation. Extensive research has been conducted concerning the adjustment of root elongation and architecture in response to environmental factors. However, little is known about the modulation of the root growth trajectory, as well as its hormonal mechanism. Here we report that abscisic acid (ABA) participated in controlling root growth trajectory. The roots upon ABA treatment or from ABA-accumulation double mutant cyp707a1,3 exhibit agravitropism-like growth pattern (wavy growth trajectory). The agravitropism-like phenotype is mainly ascribed to the compromised shootward transportation of auxin since we detected a reduced fluorescence intensity of auxin reporter DR5:VENUS in the root epidermis upon exogenous ABA application or in the endogenous ABA-accumulation double mutant cyp707a1,3. We then tried to decipher the mechanism by which ABA suppressed shootward auxin transport. The membrane abundance of PIN2, a facilitator of shootward auxin transport, was significantly reduced following ABA treatment and in cyp707a1,3. Finally, we revealed that ABA reduced the membrane PIN2 intensity through suppressing the PIN2 expression rather than accelerating PIN2 degradation. Ultimately, our results suggest a pivotal role for ABA in the root growth trajectory and the hormonal interactions orchestrating this process.
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Affiliation(s)
- Qijun Xie
- Laboratory of Photosynthesis and Environment, CAS Centre for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha, China
- Qijun Xie,
| | - Jemaa Essemine
- National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Xiaochen Pang
- Laboratory of Photosynthesis and Environment, CAS Centre for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Haiying Chen
- Laboratory of Photosynthesis and Environment, CAS Centre for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Jing Jin
- Laboratory of Photosynthesis and Environment, CAS Centre for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Weiming Cai
- Laboratory of Photosynthesis and Environment, CAS Centre for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- *Correspondence: Weiming Cai, ;
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Li E, Wang G, Zhang YL, Kong Z, Li S. FERONIA mediates root nutating growth. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:1105-1116. [PMID: 32891072 DOI: 10.1111/tpj.14984] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 08/14/2020] [Accepted: 08/19/2020] [Indexed: 06/11/2023]
Abstract
Root nutation indicates the behavior that roots grow in a waving and skewing way due to unequal growth rates on different sides. Although a few developmental and environmental factors have been reported, genetic pathways mediating this process are obscure. We report here that the Arabidopsis CrRLK1L family member FERONIA (FER) is critical for root nutation. Functional loss of FER resulted in enhanced root waviness on tilted plates or roots forming anti-clockwise coils on horizontal plates. Suppressing polar auxin transport, either by pharmacological treatment or by introducing mutations at PIN-FORMED2 (PIN2) or AUXIN RESISTANT1 (AUX1), suppressed the asymmetric root growth (ARG) in fer-4, a null mutant of FER, indicating that FER suppression of ARG depends on polar auxin transport. We further showed by pharmacological treatments that dynamic microtubule organization and Ca2+ signaling are both critical for FER-mediated ARG. Results presented here demonstrate a key role of FER in mediating root nutating growth, through PIN2- and AUX1-mediated auxin transport, through dynamic microtubule organization, and through Ca2+ signaling.
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Affiliation(s)
- En Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Guangda Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yu-Ling Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
| | - Zhaosheng Kong
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Sha Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China
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Farooq M, Jan R, Kim KM. Gravistimulation effects on Oryza sativa amino acid profile, growth pattern and expression of OsPIN genes. Sci Rep 2020; 10:17303. [PMID: 33057095 PMCID: PMC7566508 DOI: 10.1038/s41598-020-74531-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 10/01/2020] [Indexed: 11/09/2022] Open
Abstract
Gravity is an important ecological factor regulating plant growth and developmental processes. Here we used various molecular and biochemical approaches to investigate artificial and normal gravistimulation's effect on the early growth stages of rice (Oryza sativa L.) by changing the orientations of Petri dishes. Rate of amino acid formation, root and shoot growth, and OsPIN expression was significantly higher under gravistimulation compared with the control. Clinostat rotation positively affected plant growth and amino acid profile. However, under normal gravity, vertical-oriented seedlings showed high amino acid levels compared with clinostat, 90°-rotated, and control seedlings. Similarly, seedling growth significantly increased with 90°-rotated and vertical orientations. Artificial gravity and exogenous indole-3-acetic acid induced OsPIN1 expression in the roots, root shoot junction, and shoots of clinorotated seedlings. Phenyl acetic acid induced OsPIN1 expression in the roots and root shoot junction of clinorotated seedlings but not in the shoot. The current study suggests that OsPIN1 is differentially regulated and that it might be involved in the regulation of plant growth. Conversely, OsPIN2 and OsPIN3a are gravity sensors and highly induced in the roots and root shoot junctions of vertical and 90°-rotated seedlings and play an important role in stress conditions. Thus, on exposure to gravity, hormones, and UV-C radiation, these genes are highly regulated by jasmonic acid, 6-benzylaminopurine and gibberellic acid.
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Affiliation(s)
- Muhammad Farooq
- School of Applied Bioscience, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Rahmatullah Jan
- School of Applied Bioscience, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Kyung-Min Kim
- School of Applied Bioscience, Kyungpook National University, Daegu, 41566, Republic of Korea.
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Zhang S, Tajima H, Nambara E, Blumwald E, Bassil E. Auxin Homeostasis and Distribution of the Auxin Efflux Carrier PIN2 Require Vacuolar NHX-Type Cation/H + Antiporter Activity. PLANTS (BASEL, SWITZERLAND) 2020; 9:E1311. [PMID: 33023035 PMCID: PMC7601841 DOI: 10.3390/plants9101311] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/17/2020] [Accepted: 09/29/2020] [Indexed: 11/24/2022]
Abstract
The Arabidopsis vacuolar Na+/H+ transporters (NHXs) are important regulators of intracellular pH, Na+ and K+ homeostasis and necessary for normal plant growth, development, and stress acclimation. Arabidopsis contains four vacuolar NHX isoforms known as AtNHX1 to AtNHX4. The quadruple knockout nhx1nhx2nhx3nhx4, lacking any vacuolar NHX-type antiporter activity, displayed auxin-related phenotypes including loss of apical dominance, reduced root growth, impaired gravitropism and less sensitivity to exogenous IAA and NAA, but not to 2,4-D. In nhx1nhx2nhx3nhx4, the abundance of the auxin efflux carrier PIN2, but not PIN1, was drastically reduced at the plasma membrane and was concomitant with an increase in PIN2 labeled intracellular vesicles. Intracellular trafficking to the vacuole was also delayed in the mutant. Measurements of free IAA content and imaging of the auxin sensor DII-Venus, suggest that auxin accumulates in root tips of nhx1nhx2nhx3nhx4. Collectively, our results indicate that vacuolar NHX dependent cation/H+ antiport activity is needed for proper auxin homeostasis, likely by affecting intracellular trafficking and distribution of the PIN2 efflux carrier.
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Affiliation(s)
- Shiqi Zhang
- Boyce Thompson Institute, Ithaca, NY 14850, USA;
| | - Hiromi Tajima
- Department of Plant Sciences, University of California, Davis, CA 95616, USA; (H.T.); (E.B.)
| | - Eiji Nambara
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 1A1, Canada;
| | - Eduardo Blumwald
- Department of Plant Sciences, University of California, Davis, CA 95616, USA; (H.T.); (E.B.)
| | - Elias Bassil
- Horticultural Sciences Department, Tropical Research and Education Center, University of Florida, Homestead, FL 33031, USA
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Chai S, Nie Y, Li S. Nitrate deficiency induces differential endocytosis in roots through NRT1.1. PLANT SIGNALING & BEHAVIOR 2020; 15:1794394. [PMID: 32686596 PMCID: PMC8550534 DOI: 10.1080/15592324.2020.1794394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Roots grow asymmetrically, sometimes helically, around their growth direction likely to facilitate environmental sensing. We recently demonstrated that nitrate deficiency induces root coiling on horizontal surface through nitrate transporter/sensor NRT1.1 and PIN2- and AUX-mediated polar auxin transport. Here, we show that nitrate deficiency or NRT1.1 loss-of-function induces differential distribution of PIN2 between the future concave and concave sides in root epidermal cells. Treatment with pharmacological drugs suggests that enhanced endocytosis at the future convex side leads to reduced plasma membrane (PM) association of PIN2. A reduction of PIN2 at the PM would maintain a low auxin response to further enhance endocytosis at the convex side, leading to root coiling.
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Affiliation(s)
- Sen Chai
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
- College of Horticulture, Qingdao Agricultural University, Qingdao, China
| | - Yongxin Nie
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
| | - Sha Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China
- CONTACT Sha Li, State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an271018, China
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Su SH, Keith MA, Masson PH. Gravity Signaling in Flowering Plant Roots. PLANTS (BASEL, SWITZERLAND) 2020; 9:E1290. [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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Affiliation(s)
| | | | - Patrick H. Masson
- Laboratory of Genetics, University of Wisconsin-Madison, 425G Henry Mall, Madison, WI 53706, USA; (S.-H.S.); (M.A.K.)
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Jiménez-Vázquez KR, García-Cárdenas E, Barrera-Ortiz S, Ortiz-Castro R, Ruiz-Herrera LF, Ramos-Acosta BP, Coria-Arellano JL, Sáenz-Mata J, López-Bucio J. The plant beneficial rhizobacterium Achromobacter sp. 5B1 influences root development through auxin signaling and redistribution. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:1639-1654. [PMID: 32445404 DOI: 10.1111/tpj.14853] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 05/10/2020] [Accepted: 05/15/2020] [Indexed: 05/20/2023]
Abstract
Roots provide physical and nutritional support to plant organs that are above ground and play critical roles for adaptation via intricate movements and growth patterns. Through screening the effects of bacterial isolates from roots of halophyte Mesquite (Prosopis sp.) on Arabidopsis thaliana, we identified Achromobacter sp. 5B1 as a probiotic bacterium that influences plant functional traits. Detailed genetic and architectural analyses in Arabidopsis grown in vitro and in soil, cell division measurements, auxin transport and response gene expression and brefeldin A treatments demonstrated that root colonization with Achromobacter sp. 5B1 changes the growth and branching patterns of roots, which were related to auxin perception and redistribution. Expression analysis of auxin transport and signaling revealed a redistribution of auxin within the primary root tip of wild-type seedlings by Achromobacter sp. 5B1 that is disrupted by brefeldin A and correlates with repression of auxin transporters PIN1 and PIN7 in root provasculature, and PIN2 in the epidermis and cortex of the root tip, whereas expression of PIN3 was enhanced in the columella. In seedlings harboring AUX1, EIR1, AXR1, ARF7ARF19, TIR1AFB2AFB3 single, double or triple loss-of-function mutations, or in a dominant (gain-of-function) mutant of SLR1, the bacterium caused primary roots to form supercoils that are devoid of lateral roots. The changes in growth and root architecture elicited by the bacterium helped Arabidopsis seedlings to resist salt stress better. Thus, Achromobacter sp. 5B1 fine tunes both root movements and the auxin response, which may be important for plant growth and environmental adaptation.
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Affiliation(s)
- Kirán R Jiménez-Vázquez
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, Morelia, Michoacán, C. P. 58030, México
| | - Elizabeth García-Cárdenas
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, Morelia, Michoacán, C. P. 58030, México
| | - Salvador Barrera-Ortiz
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, Morelia, Michoacán, C. P. 58030, México
| | - Randy Ortiz-Castro
- Red de Estudios Moleculares Avanzados, Instituto de Ecología A. C., Carretera Antigua a Coatepec 351 El Haya, Xalapa, Veracruz, 91070, México
| | - León F Ruiz-Herrera
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, Morelia, Michoacán, C. P. 58030, México
| | - Blanca P Ramos-Acosta
- Facultad de Ciencias Biológicas, Universidad Juárez del Estado de Durango, Av. Universidad S/N, Frac. Filadelfia, Gómez Palacio, Durango, C.P. 35010, México
| | - Jessica L Coria-Arellano
- Facultad de Ciencias Biológicas, Universidad Juárez del Estado de Durango, Av. Universidad S/N, Frac. Filadelfia, Gómez Palacio, Durango, C.P. 35010, México
| | - Jorge Sáenz-Mata
- Facultad de Ciencias Biológicas, Universidad Juárez del Estado de Durango, Av. Universidad S/N, Frac. Filadelfia, Gómez Palacio, Durango, C.P. 35010, México
| | - José López-Bucio
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, Morelia, Michoacán, C. P. 58030, México
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Mellor NL, Voß U, Janes G, Bennett MJ, Wells DM, Band LR. Auxin fluxes through plasmodesmata modify root-tip auxin distribution. Development 2020; 147:dev181669. [PMID: 32229613 PMCID: PMC7132777 DOI: 10.1242/dev.181669] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 02/17/2020] [Indexed: 01/05/2023]
Abstract
Auxin is a key signal regulating plant growth and development. It is well established that auxin dynamics depend on the spatial distribution of efflux and influx carriers on the cell membranes. In this study, we employ a systems approach to characterise an alternative symplastic pathway for auxin mobilisation via plasmodesmata, which function as intercellular pores linking the cytoplasm of adjacent cells. To investigate the role of plasmodesmata in auxin patterning, we developed a multicellular model of the Arabidopsis root tip. We tested the model predictions using the DII-VENUS auxin response reporter, comparing the predicted and observed DII-VENUS distributions using genetic and chemical perturbations designed to affect both carrier-mediated and plasmodesmatal auxin fluxes. The model revealed that carrier-mediated transport alone cannot explain the experimentally determined auxin distribution in the root tip. In contrast, a composite model that incorporates both carrier-mediated and plasmodesmatal auxin fluxes re-capitulates the root-tip auxin distribution. We found that auxin fluxes through plasmodesmata enable auxin reflux and increase total root-tip auxin. We conclude that auxin fluxes through plasmodesmata modify the auxin distribution created by efflux and influx carriers.
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Affiliation(s)
- Nathan L Mellor
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Ute Voß
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - George Janes
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Malcolm J Bennett
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Darren M Wells
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Leah R Band
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, UK
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Upadhyay N, Kar D, Datta S. A multidrug and toxic compound extrusion (MATE) transporter modulates auxin levels in root to regulate root development and promotes aluminium tolerance. PLANT, CELL & ENVIRONMENT 2020; 43:745-759. [PMID: 31677167 DOI: 10.1111/pce.13658] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 09/15/2019] [Accepted: 09/17/2019] [Indexed: 05/10/2023]
Abstract
MATE (multidrug and toxic compound extrusion) transporters play multiple roles in plants including detoxification, secondary metabolite transport, aluminium (Al) tolerance, and disease resistance. Here we identify and characterize the role of the Arabidopsis MATE transporter DETOXIFICATION30. AtDTX30 regulates auxin homeostasis in Arabidopsis roots to modulate root development and Al-tolerance. DTX30 is primarily expressed in roots and localizes to the plasma membrane of root epidermal cells including root hairs. dtx30 mutants exhibit reduced elongation of the primary root, root hairs, and lateral roots. The mutant seedlings accumulate more auxin in their root tips indicating role of DTX30 in maintaining auxin homeostasis in the root. Al induces DTX30 expression and promotes its localization to the distal transition zone. dtx30 seedlings accumulate more Al in their roots but are hyposensitive to Al-mediated rhizotoxicity perhaps due to saturation in root growth inhibition. Increase in expression of ethylene and auxin biosynthesis genes in presence of Al is absent in dtx30. The mutants exude less citrate under Al conditions, which might be due to misregulation of AtSTOP1 and the citrate transporter AtMATE. In conclusion, DTX30 modulates auxin levels in root to regulate root development and in the presence of Al indirectly modulates citrate exudation to promote Al tolerance.
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Affiliation(s)
- Neha Upadhyay
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, 462066, India
| | - Debojyoti Kar
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, 462066, India
| | - Sourav Datta
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, 462066, India
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Ng JLP, Welvaert A, Wen J, Chen R, Mathesius U. The Medicago truncatula PIN2 auxin transporter mediates basipetal auxin transport but is not necessary for nodulation. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:1562-1573. [PMID: 31738415 DOI: 10.1093/jxb/erz510] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
The development of root nodules leads to an increased auxin response in early nodule primordia, which is mediated by changes in acropetal auxin transport in some legumes. Here, we investigated the role of root basipetal auxin transport during nodulation. Rhizobia inoculation significantly increased basipetal auxin transport in both Medicago truncatula and Lotus japonicus. In M. truncatula, this increase was dependent on functional Nod factor signalling through NFP, NIN, and NSP2, as well as ethylene signalling through SKL. To test whether increased basipetal auxin transport is required for nodulation, we examined a loss-of-function mutant of the M. truncatula PIN2 gene. The Mtpin2 mutant exhibited a reduction in basipetal auxin transport and an agravitropic phenotype. Inoculation of Mtpin2 roots with rhizobia still led to a moderate increase in basipetal auxin transport, but the mutant nodulated normally. No clear differences in auxin response were observed during nodule development. Interestingly, inoculation of wild-type roots increased lateral root numbers, whereas inoculation of Mtpin2 mutants resulted in reduced lateral root numbers compared with uninoculated roots. We conclude that the MtPIN2 auxin transporter is involved in basipetal auxin transport, that its function is not essential for nodulation, but that it plays an important role in the control of lateral root development.
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Affiliation(s)
- Jason L P Ng
- Division of Plant Science, Research School of Biology, Australian National University, Canberra, Australia
| | - Astrid Welvaert
- Division of Plant Science, Research School of Biology, Australian National University, Canberra, Australia
| | - Jiangqi Wen
- Noble Research Institute LLC, Ardmore, OK, USA
| | - Rujin Chen
- School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Ulrike Mathesius
- Division of Plant Science, Research School of Biology, Australian National University, Canberra, Australia
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Tang RJ, Luan M, Wang C, Lhamo D, Yang Y, Zhao FG, Lan WZ, Fu AG, Luan S. Plant Membrane Transport Research in the Post-genomic Era. PLANT COMMUNICATIONS 2020; 1:100013. [PMID: 33404541 PMCID: PMC7747983 DOI: 10.1016/j.xplc.2019.100013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/14/2019] [Accepted: 12/06/2019] [Indexed: 05/17/2023]
Abstract
Membrane transport processes are indispensable for many aspects of plant physiology including mineral nutrition, solute storage, cell metabolism, cell signaling, osmoregulation, cell growth, and stress responses. Completion of genome sequencing in diverse plant species and the development of multiple genomic tools have marked a new era in understanding plant membrane transport at the mechanistic level. Genes coding for a galaxy of pumps, channels, and carriers that facilitate various membrane transport processes have been identified while multiple approaches are developed to dissect the physiological roles as well as to define the transport capacities of these transport systems. Furthermore, signaling networks dictating the membrane transport processes are established to fully understand the regulatory mechanisms. Here, we review recent research progress in the discovery and characterization of the components in plant membrane transport that take advantage of plant genomic resources and other experimental tools. We also provide our perspectives for future studies in the field.
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Affiliation(s)
- Ren-Jie Tang
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Mingda Luan
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Chao Wang
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Dhondup Lhamo
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Yang Yang
- Nanjing University–Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Fu-Geng Zhao
- Nanjing University–Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Wen-Zhi Lan
- Nanjing University–Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Ai-Gen Fu
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Sheng Luan
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
- Corresponding author
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Chai S, Li E, Zhang Y, Li S. NRT1.1-Mediated Nitrate Suppression of Root Coiling Relies on PIN2- and AUX1-Mediated Auxin Transport. FRONTIERS IN PLANT SCIENCE 2020; 11:671. [PMID: 32582237 PMCID: PMC7288464 DOI: 10.3389/fpls.2020.00671] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 04/29/2020] [Indexed: 05/03/2023]
Abstract
Asymmetric root growth (ARG) on tilted plates, or root coiling on horizontally placed plates, is proposed to be a combination of gravitropism, mechanical sensing, and "circumnutation," a word designated by Charles Darwin to describe the helical movement that all plant organs make around the growth direction. ARG is developmentally controlled in which microtubule-regulating proteins and the phytohormone auxin participates. Nutrient deficiency influences ARG. However, it is unclear which nutrients play key roles in regulating ARG, what endogenous components are involved in responding to nutrient deficiency for ARG, and how nutrient deficiency is translated into endogenous responses. We report here that nitrate deficiency resulted in a strong ARG in Arabidopsis. Nitrate deficiency caused root coiling on horizontal plates, which is inhibited by an auxin transport inhibitor, and by mutations in PIN-FORMED2 (PIN2) and AUXIN RESISTANT 1 (AUX1). We further show that suppression of ARG by nitrate is mediated by the nitrate transporter/sensor NRT1.1. In addition, PIN2- and AUX1-mediated auxin transports are epistatic to NRT1.1 in nitrate deficiency-induced ARG. This study reveals a signaling pathway in root growth by responding to exogenous nitrate and relaying it into altered auxin transport.
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Verna C, Ravichandran SJ, Sawchuk MG, Linh NM, Scarpella E. Coordination of tissue cell polarity by auxin transport and signaling. eLife 2019; 8:51061. [PMID: 31793881 PMCID: PMC6890459 DOI: 10.7554/elife.51061] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 11/01/2019] [Indexed: 02/02/2023] Open
Abstract
Plants coordinate the polarity of hundreds of cells during vein formation, but how they do so is unclear. The prevailing hypothesis proposes that GNOM, a regulator of membrane trafficking, positions PIN-FORMED auxin transporters to the correct side of the plasma membrane; the resulting cell-to-cell, polar transport of auxin would coordinate tissue cell polarity and induce vein formation. Contrary to predictions of the hypothesis, we find that vein formation occurs in the absence of PIN-FORMED or any other intercellular auxin-transporter; that the residual auxin-transport-independent vein-patterning activity relies on auxin signaling; and that a GNOM-dependent signal acts upstream of both auxin transport and signaling to coordinate tissue cell polarity and induce vein formation. Our results reveal synergism between auxin transport and signaling, and their unsuspected control by GNOM in the coordination of tissue cell polarity during vein patterning, one of the most informative expressions of tissue cell polarization in plants. Plants, animals and other living things grow and develop over their lifetimes: for example, oak trees come from acorns and chickens begin their lives as eggs. To achieve these transformations, the cells in those living things must grow, divide and change their shape and other features. Plants and animals specify the directions in which their cells will grow and develop by gathering specific proteins to one side of the cells. This makes one side different from all the other sides, which the cells use as an internal compass that points in one direction. To align their internal compasses, animal cells touch one another and often move around inside the body. Plant cells, on the other hand, are surrounded by a wall that keeps them apart and prevents them from moving around. So how do plant cells align their internal compasses? Scientists have long thought that a protein called GNOM aligns the internal compasses of plant cells. The hypothesis proposes that GNOM gathers another protein, called PIN1, to one side of a cell. PIN1 would then pump a plant hormone known as auxin out of this first cell and, in doing so, would also drain auxin away from the cell on the opposite side. In this second cell, GNOM would then gather PIN1 to the side facing the first cell, and this process would repeat until all the cells' compasses were aligned. To test this hypothesis, Verna et al. combined microscopy with genetic approaches to study how cells' compasses are aligned in the leaves of a plant called Arabidopsis thaliana. The experiments revealed that auxin needs to move from cell-to-cell to align the cells’ compasses. However, contrary to the above hypothesis, this movement of auxin was not sufficient: the cells also needed to be able to detect and respond to the auxin that entered them. Along with controlling how auxin moved between the cells, GNOM also regulated how the cells responded to the auxin. These findings reveal how plants specify which directions their cells grow and develop. In the future, this knowledge may eventually aid efforts to improve crop yields by controlling the growth and development of crop plants.
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Affiliation(s)
- Carla Verna
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
| | | | - Megan G Sawchuk
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
| | - Nguyen Manh Linh
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
| | - Enrico Scarpella
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
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Lee KH, Du Q, Zhuo C, Qi L, Wang H. LBD29-Involved Auxin Signaling Represses NAC Master Regulators and Fiber Wall Biosynthesis. PLANT PHYSIOLOGY 2019; 181:595-608. [PMID: 31377726 PMCID: PMC6776862 DOI: 10.1104/pp.19.00148] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 07/31/2019] [Indexed: 05/18/2023]
Abstract
NAM, ATAF1/2 and CUC2 (NAC) domain transcription factors function as master switches in regulating secondary cell wall (SCW) biosynthesis in Arabidopsis (Arabidopsis thaliana) stems. Despite the importance of these NACs in fiber development, the upstream signal is still elusive. Using a large-scale mutant screening, we identified a dominant activation-tagging mutant, fiberless-d (fls-d), showing defective SCW development in stem fibers, similar to that of the nac secondary wall thickening promoting factor1-1 (nst1-1)nst3-3 double mutant. Overexpression of LATERAL ORGAN BOUNDARIES DOMAIN29 (LBD29) is responsible for the fls-d mutant phenotypes. By contrast, loss-of-function of LBD29, either in the dominant repression transgenic lines or in the transfer-DNA (T-DNA) insertion mutant lbd29-1, enhanced SCW development in fibers. Genetic analysis and transgenic studies demonstrated LBD29 depends on master regulators in mediating SCW biosynthesis, specifically NAC SECONDARY WALL THICKENING PROMOTING FACTOR1 (NST1), NST2, and NST3. Increasing indole-3-acetic acid (IAA) levels, either in stem tissues above a N-1-naphthylphthalamic acid-treated region or in plants directly sprayed with IAA, inhibits fiber wall thickening. The inhibition effect of naphthylphthalamic acid treatment and exogenous IAA application depends on a known auxin signaling pathway involving AUXIN RESPONSE FACTOR7 (ARF7)/ARF19 and LBD29. These results demonstrate auxin is upstream of LBD29 in repressing NAC master regulators, and therefore shed new light on the regulation of SCW biosynthesis in Arabidopsis.
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Affiliation(s)
- Kwang-Hee Lee
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269
| | - Qian Du
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269
| | - Chunliu Zhuo
- Department of Biological Sciences, University of North Texas, Denton, Texas 76203
| | - Liying Qi
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269
| | - Huanzhong Wang
- Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269
- Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut 06269
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Ge L, Chen R. Negative gravitropic response of roots directs auxin flow to control root gravitropism. PLANT, CELL & ENVIRONMENT 2019; 42:2372-2383. [PMID: 30968964 DOI: 10.1111/pce.13559] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 02/21/2019] [Accepted: 04/05/2019] [Indexed: 05/03/2023]
Abstract
Root tip is capable of sensing and adjusting its growth direction in response to gravity, a phenomenon known as root gravitropism. Previously, we have shown that negative gravitropic response of roots (NGR) is essential for the positive gravitropic response of roots. Here, we show that NGR, a plasma membrane protein specifically expressed in root columella and lateral root cap cells, controls the positive root gravitropic response by regulating auxin efflux carrier localization in columella cells and the direction of lateral auxin flow in response to gravity. Pharmacological and genetic studies show that the negative root gravitropic response of the ngr mutants depends on polar auxin transport in the root elongation zone. Cell biology studies further demonstrate that polar localization of the auxin efflux carrier PIN3 in root columella cells and asymmetric lateral auxin flow in the root tip in response to gravistimulation is reversed in the atngr1;2;3 triple mutant. Furthermore, simultaneous mutations of three PIN genes expressed in root columella cells impaired the negative root gravitropic response of the atngr1;2;3 triple mutant. Our work revealed a critical role of NGR in root gravitropic response and provided an insight of the early events and molecular basis of the positive root gravitropism.
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Affiliation(s)
- Liangfa Ge
- Department of Grass Science, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou, 510642, China
- Laboratory of Plant Genetics and Development, Noble Research Institute, Ardmore, 73401, Oklahoma
| | - Rujin Chen
- School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
- Laboratory of Plant Genetics and Development, Noble Research Institute, Ardmore, 73401, Oklahoma
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41
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Zwiewka M, Bilanovičová V, Seifu YW, Nodzyński T. The Nuts and Bolts of PIN Auxin Efflux Carriers. FRONTIERS IN PLANT SCIENCE 2019; 10:985. [PMID: 31417597 PMCID: PMC6685051 DOI: 10.3389/fpls.2019.00985] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 07/12/2019] [Indexed: 05/20/2023]
Abstract
The plant-specific proteins named PIN-FORMED (PIN) efflux carriers facilitate the direction of auxin flow and thus play a vital role in the establishment of local auxin maxima within plant tissues that subsequently guide plant ontogenesis. They are membrane integral proteins with two hydrophobic regions consisting of alpha-helices linked with a hydrophilic loop, which is usually longer for the plasma membrane-localized PINs. The hydrophilic loop harbors molecular cues important for the subcellular localization and thus auxin efflux function of those transporters. The three-dimensional structure of PIN has not been solved yet. However, there are scattered but substantial data concerning the functional characterization of amino acid strings that constitute these carriers. These sequences include motifs vital for vesicular trafficking, residues regulating membrane diffusion, cellular polar localization, and activity of PINs. Here, we summarize those bits of information striving to provide a reference to structural motifs that have been investigated experimentally hoping to stimulate the efforts toward unraveling of PIN structure-function connections.
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Affiliation(s)
| | | | | | - Tomasz Nodzyński
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czechia
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Motte H, Vanneste S, Beeckman T. Molecular and Environmental Regulation of Root Development. ANNUAL REVIEW OF PLANT BIOLOGY 2019; 70:465-488. [PMID: 30822115 DOI: 10.1146/annurev-arplant-050718-100423] [Citation(s) in RCA: 171] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
In order to optimally establish their root systems, plants are endowed with several mechanisms to use at distinct steps during their development. In this review, we zoom in on the major processes involved in root development and detail important new insights that have been generated in recent studies, mainly using the Arabidopsis root as a model. First, we discuss new insights in primary root development with the characterization of tissue-specific transcription factor complexes and the identification of non-cell-autonomous control mechanisms in the root apical meristem. Next, root branching is discussed by focusing on the earliest steps in the development of a new lateral root and control of its postemergence growth. Finally, we discuss the impact of phosphate, nitrogen, and water availability on root development and summarize current knowledge about the major molecular mechanisms involved.
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Affiliation(s)
- Hans Motte
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium;
| | - Steffen Vanneste
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium;
- Lab of Plant Growth Analysis, Ghent University Global Campus, Incheon 21985, Republic of Korea
| | - Tom Beeckman
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium;
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Matthes MS, Best NB, Robil JM, Malcomber S, Gallavotti A, McSteen P. Auxin EvoDevo: Conservation and Diversification of Genes Regulating Auxin Biosynthesis, Transport, and Signaling. MOLECULAR PLANT 2019; 12:298-320. [PMID: 30590136 DOI: 10.1016/j.molp.2018.12.012] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 12/02/2018] [Accepted: 12/16/2018] [Indexed: 05/08/2023]
Abstract
The phytohormone auxin has been shown to be of pivotal importance in growth and development of land plants. The underlying molecular players involved in auxin biosynthesis, transport, and signaling are quite well understood in Arabidopsis. However, functional characterizations of auxin-related genes in economically important crops, specifically maize and rice, are still limited. In this article, we comprehensively review recent functional studies on auxin-related genes in both maize and rice, compared with what is known in Arabidopsis, and highlight conservation and diversification of their functions. Our analysis is illustrated by phylogenetic analysis and publicly available gene expression data for each gene family, which will aid in the identification of auxin-related genes for future research. Current challenges and future directions for auxin research in maize and rice are discussed. Developments in gene editing techniques provide powerful tools for overcoming the issue of redundancy in these gene families and will undoubtedly advance auxin research in crops.
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Affiliation(s)
- Michaela Sylvia Matthes
- Division of Biological Sciences, Interdisciplinary Plant Group and Missouri Maize Center, University of Missouri-Columbia, 301 Christopher Bond Life Sciences Center, Columbia, MO 65211, USA
| | - Norman Bradley Best
- Division of Biological Sciences, Interdisciplinary Plant Group and Missouri Maize Center, University of Missouri-Columbia, 301 Christopher Bond Life Sciences Center, Columbia, MO 65211, USA
| | - Janlo M Robil
- Division of Biological Sciences, Interdisciplinary Plant Group and Missouri Maize Center, University of Missouri-Columbia, 301 Christopher Bond Life Sciences Center, Columbia, MO 65211, USA
| | - Simon Malcomber
- Department of Biological Sciences, California State University, Long Beach, CA 90840, USA
| | - Andrea Gallavotti
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854-8020, USA; Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA
| | - Paula McSteen
- Division of Biological Sciences, Interdisciplinary Plant Group and Missouri Maize Center, University of Missouri-Columbia, 301 Christopher Bond Life Sciences Center, Columbia, MO 65211, USA.
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Méndez-Bravo A, Ruiz-Herrera LF, Cruz-Ramírez A, Guzman P, Martínez-Trujillo M, Ortiz-Castro R, López-Bucio J. CONSTITUTIVE TRIPLE RESPONSE1 and PIN2 act in a coordinate manner to support the indeterminate root growth and meristem cell proliferating activity in Arabidopsis seedlings. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 280:175-186. [PMID: 30823995 DOI: 10.1016/j.plantsci.2018.11.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 11/24/2018] [Accepted: 11/28/2018] [Indexed: 05/26/2023]
Abstract
The plant hormone ethylene induces auxin biosynthesis and transport and modulates root growth and branching. However, its function on root stem cells and the identity of interacting factors for the control of meristem activity remains unclear. Genetic analysis for primary root growth in wild-type (WT) Arabidopsis thaliana seedlings and ethylene-related mutants showed that the loss-of-function of CONSTITUTIVE TRIPLE RESPONSE1 (CTR1) inhibits cell division and elongation. This phenotype is associated with an increase in the expression of the auxin transporter PIN2 and a drastic decrease in the expression of key factors for stem cell niche maintenance such as PLETHORA1, SHORT ROOT and SCARECROW. While the root stem cell niche is affected in ctr1 mutants, its maintenance is severely compromised in the ctr1-1eir1-1(pin2) double mutant, in which an evident loss of proliferative capacity of the meristematic cells leads to a fully differentiated root meristem shortly after germination. Root traits affected in ctr1-1 mutants could be restored in ctr1-1ein2-1 double mutants. These results reveal that ethylene perception via CTR1 and EIN2 in the root modulates the proliferative capacity of root stem cells via affecting the expression of genes involved in the two major pathways, AUX-PIN-PLT and SCR-SHR, which are key factors for proper root stem cell niche maintenance.
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Affiliation(s)
- Alejandro Méndez-Bravo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P. 58030, Morelia, Michoacán, Mexico
| | - León Francisco Ruiz-Herrera
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P. 58030, Morelia, Michoacán, Mexico
| | - Alfredo Cruz-Ramírez
- Molecular and Developmental Complexity Group, Unidad de Genómica Avanzada, Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Campus Irapuato, Guanajuato, Mexico
| | - Plinio Guzman
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados del IPN, Campus Irapuato, Guanajuato, Mexico
| | - Miguel Martínez-Trujillo
- Facultad de Biología, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, C. P. 58030, Morelia, Michoacán, Mexico
| | - Randy Ortiz-Castro
- Red de estudios moleculares avanzados, Instituto de Ecología A. C., Carretera Antigua a Coatepec 351, El Haya, C. P. 91070, Xalapa, Veracruz, Mexico
| | - José López-Bucio
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, C. P. 58030, Morelia, Michoacán, Mexico.
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Swarup R, Bhosale R. Developmental Roles of AUX1/LAX Auxin Influx Carriers in Plants. FRONTIERS IN PLANT SCIENCE 2019; 10:1306. [PMID: 31719828 PMCID: PMC6827439 DOI: 10.3389/fpls.2019.01306] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 09/19/2019] [Indexed: 05/06/2023]
Abstract
Plant hormone auxin regulates several aspects of plant growth and development. Auxin is predominantly synthesized in the shoot apex and developing leaf primordia and from there it is transported to the target tissues e.g. roots. Auxin transport is polar in nature and is carrier-mediated. AUXIN1/LIKE-AUX1 (AUX1/LAX) family members are the major auxin influx carriers whereas PIN-FORMED (PIN) family and some members of the P-GLYCOPROTEIN/ATP-BINDING CASSETTE B4 (PGP/ABCB) family are major auxin efflux carriers. AUX1/LAX auxin influx carriers are multi-membrane spanning transmembrane proteins sharing similarity to amino acid permeases. Mutations in AUX1/LAX genes result in auxin related developmental defects and have been implicated in regulating key plant processes including root and lateral root development, root gravitropism, root hair development, vascular patterning, seed germination, apical hook formation, leaf morphogenesis, phyllotactic patterning, female gametophyte development and embryo development. Recently AUX1 has also been implicated in regulating plant responses to abiotic stresses. This review summarizes our current understanding of the developmental roles of AUX1/LAX gene family and will also briefly discuss the modelling approaches that are providing new insight into the role of auxin transport in plant development.
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Affiliation(s)
- Ranjan Swarup
- Plant and Crop Sciences, School of Biosciences, University of Nottingham, Nottingham, United Kingdom
- Center for Plant Integrative Biology (CPIB), University of Nottingham, Nottingham, United Kingdom
- *Correspondence: Ranjan Swarup,
| | - Rahul Bhosale
- Plant and Crop Sciences, School of Biosciences, University of Nottingham, Nottingham, United Kingdom
- Center for Plant Integrative Biology (CPIB), University of Nottingham, Nottingham, United Kingdom
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Abstract
Regulation of plant root angle is critical for obtaining nutrients and water and is an important trait for plant breeding. A plant’s final, long-term root angle is the net result of a complex series of decisions made by a root tip in response to changes in nutrient availability, impediments, the gravity vector and other stimuli. When a root tip is displaced from the gravity vector, the short-term process of gravitropism results in rapid reorientation of the root toward the vertical. Here, we explore both short- and long-term regulation of root growth angle, using natural variation in tomato to identify shared and separate genetic features of the two responses. Mapping of expression quantitative trait loci mapping and leveraging natural variation between and within species including Arabidopsis suggest a role for PURPLE ACID PHOSPHATASE 27 and CELL DIVISION CYCLE 73 in determining root angle.
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Krishnamurthy A, Ferl RJ, Paul A. Comparing RNA-Seq and microarray gene expression data in two zones of the Arabidopsis root apex relevant to spaceflight. APPLICATIONS IN PLANT SCIENCES 2018; 6:e01197. [PMID: 30473943 PMCID: PMC6240453 DOI: 10.1002/aps3.1197] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 10/07/2018] [Indexed: 05/21/2023]
Abstract
PREMISE OF THE STUDY The root apex is an important region involved in environmental sensing, but comprises a very small part of the root. Obtaining root apex transcriptomes is therefore challenging when the samples are limited. The feasibility of using tiny root sections for transcriptome analysis was examined, comparing RNA sequencing (RNA-Seq) to microarrays in characterizing genes that are relevant to spaceflight. METHODS Arabidopsis thaliana Columbia ecotype (Col-0) roots were sectioned into Zone 1 (0.5 mm; root cap and meristematic zone) and Zone 2 (1.5 mm; transition, elongation, and growth-terminating zone). Differential gene expression in each was compared. RESULTS Both microarrays and RNA-Seq proved applicable to the small samples. A total of 4180 genes were differentially expressed (with fold changes of 2 or greater) between Zone 1 and Zone 2. In addition, 771 unique genes and 19 novel transcriptionally active regions were identified by RNA-Seq that were not detected in microarrays. However, microarrays detected spaceflight-relevant genes that were missed in RNA-Seq. DISCUSSION Single root tip subsections can be used for transcriptome analysis using either RNA-Seq or microarrays. Both RNA-Seq and microarrays provided novel information. These data suggest that techniques for dealing with small, rare samples from spaceflight can be further enhanced, and that RNA-Seq may miss some spaceflight-relevant changes in gene expression.
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Affiliation(s)
- Aparna Krishnamurthy
- Department of Horticultural SciencesProgram in Plant Molecular and Cellular BiologyUniversity of FloridaGainesvilleFlorida32611USA
| | - Robert J. Ferl
- Department of Horticultural SciencesProgram in Plant Molecular and Cellular BiologyUniversity of FloridaGainesvilleFlorida32611USA
- Interdisciplinary Center for BiotechnologyUniversity of FloridaGainesvilleFlorida32611USA
| | - Anna‐Lisa Paul
- Department of Horticultural SciencesProgram in Plant Molecular and Cellular BiologyUniversity of FloridaGainesvilleFlorida32611USA
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Miao ZQ, Zhao PX, Mao JL, Yu LH, Yuan Y, Tang H, Liu ZB, Xiang CB. HOMEOBOX PROTEIN52 Mediates the Crosstalk between Ethylene and Auxin Signaling during Primary Root Elongation by Modulating Auxin Transport-Related Gene Expression. THE PLANT CELL 2018; 30:2761-2778. [PMID: 30333147 PMCID: PMC6305987 DOI: 10.1105/tpc.18.00584] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/26/2018] [Accepted: 10/14/2018] [Indexed: 05/06/2023]
Abstract
The gaseous hormone ethylene participates in many physiological processes in plants. Ethylene-inhibited root elongation involves PIN-FORMED2 (PIN2)-mediated basipetal auxin transport, but the molecular mechanisms underlying the regulation of PIN2 function by ethylene (and therefore auxin distribution) are poorly understood. Here, we report that the plant-specific and ethylene-responsive HD-Zip gene HB52 is involved in ethylene-mediated inhibition of primary root elongation in Arabidopsis thaliana Biochemical and genetic analyses demonstrated that HB52 is ethylene responsive and acts downstream of ETHYLENE-INSENSITIVE3 (EIN3). HB52 knockdown mutants displayed an ethylene-insensitive phenotype during primary root elongation, while its overexpression resulted in short roots, as observed in ethylene-treated plants. In addition, root auxin distribution and gravitropism were impaired in HB52 knockdown and overexpression lines. Consistent with these findings, in vitro and in vivo binding experiments showed that HB52 regulates the expression of auxin transport-related genes, including PIN2, WAVY ROOT GROWTH1 (WAG1), and WAG2 by physically binding to their promoter regions. These findings suggest that HB52 functions in the ethylene-mediated inhibition of root elongation by modulating the expression of auxin transport components downstream of EIN3, revealing a mechanism in which HB52 acts as an important node in the crosstalk between ethylene and auxin signaling during plant growth and development.
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Affiliation(s)
- Zi-Qing Miao
- School of Life Sciences and Division of Molecular and Cell Biophysics, Hefei National Science Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui Province 230027, China
| | - Ping-Xia Zhao
- School of Life Sciences and Division of Molecular and Cell Biophysics, Hefei National Science Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui Province 230027, China
| | - Jie-Li Mao
- School of Life Sciences and Division of Molecular and Cell Biophysics, Hefei National Science Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui Province 230027, China
| | - Lin-Hui Yu
- School of Life Sciences and Division of Molecular and Cell Biophysics, Hefei National Science Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui Province 230027, China
| | - Yang Yuan
- School of Life Sciences and Division of Molecular and Cell Biophysics, Hefei National Science Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui Province 230027, China
| | - Hui Tang
- School of Life Sciences and Division of Molecular and Cell Biophysics, Hefei National Science Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui Province 230027, China
| | - Zhen-Bang Liu
- School of Life Sciences and Division of Molecular and Cell Biophysics, Hefei National Science Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui Province 230027, China
| | - Cheng-Bin Xiang
- School of Life Sciences and Division of Molecular and Cell Biophysics, Hefei National Science Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui Province 230027, China
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49
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Chen J, Zhang L, Zhu M, Han L, Lv Y, Liu Y, Li P, Jing H, Cai H. Non-dormant Axillary Bud 1 regulates axillary bud outgrowth in sorghum. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2018; 60:938-955. [PMID: 29740955 DOI: 10.1111/jipb.12665] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 05/04/2018] [Indexed: 06/08/2023]
Abstract
Tillering contributes to grain yield and plant architecture and therefore is an agronomically important trait in sorghum (Sorghum bicolor). Here, we identified and functionally characterized a mutant of the Non-dormant Axillary Bud 1 (NAB1) gene from an ethyl methanesulfonate-mutagenized sorghum population. The nab1 mutants have increased tillering and reduced plant height. Map-based cloning revealed that NAB1 encodes a carotenoid-cleavage dioxygenase 7 (CCD7) orthologous to rice (Oryza sativa) HIGH-TILLERING DWARF1/DWARF17 and Arabidopsis thaliana MORE AXILLARY BRANCHING 3. NAB1 is primarily expressed in axillary nodes and tiller bases and NAB1 localizes to chloroplasts. The nab1 mutation causes outgrowth of basal axillary buds; removing these non-dormant basal axillary buds restored the wild-type phenotype. The tillering of nab1 plants was completely suppressed by exogenous application of the synthetic strigolactone analog GR24. Moreover, the nab1 plants had no detectable strigolactones and displayed stronger polar auxin transport than wild-type plants. Finally, RNA-seq showed that the expression of genes involved in multiple processes, including auxin-related genes, was significantly altered in nab1. These results suggest that NAB1 functions in strigolactone biosynthesis and the regulation of shoot branching via an interaction with auxin transport.
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Affiliation(s)
- Jun Chen
- Department of Plant Genetics, Breeding and Seed Science, China Agricultural University; Beijing Key Laboratory of Crop Genetic Improvement; Laboratory of Crop Heterosis and Utilization, MOE; Beijing 100193, China
| | - Limin Zhang
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Mengjiao Zhu
- Department of Plant Genetics, Breeding and Seed Science, China Agricultural University; Beijing Key Laboratory of Crop Genetic Improvement; Laboratory of Crop Heterosis and Utilization, MOE; Beijing 100193, China
| | - Lijie Han
- Department of Plant Genetics, Breeding and Seed Science, China Agricultural University; Beijing Key Laboratory of Crop Genetic Improvement; Laboratory of Crop Heterosis and Utilization, MOE; Beijing 100193, China
| | - Ya Lv
- Department of Plant Genetics, Breeding and Seed Science, China Agricultural University; Beijing Key Laboratory of Crop Genetic Improvement; Laboratory of Crop Heterosis and Utilization, MOE; Beijing 100193, China
| | - Yishan Liu
- Department of Plant Genetics, Breeding and Seed Science, China Agricultural University; Beijing Key Laboratory of Crop Genetic Improvement; Laboratory of Crop Heterosis and Utilization, MOE; Beijing 100193, China
| | - Pan Li
- Department of Plant Genetics, Breeding and Seed Science, China Agricultural University; Beijing Key Laboratory of Crop Genetic Improvement; Laboratory of Crop Heterosis and Utilization, MOE; Beijing 100193, China
| | - Haichun Jing
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Inner Mongolia Research Centre for Practaculture, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongwei Cai
- Department of Plant Genetics, Breeding and Seed Science, China Agricultural University; Beijing Key Laboratory of Crop Genetic Improvement; Laboratory of Crop Heterosis and Utilization, MOE; Beijing 100193, China
- Forage Crop Research Institute, Japan Grassland Agricultural and Forage Seed Association, 388-5 Higashiakada, Nasushiobara, Tochigi 329-2742, Japan
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50
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Zhou JJ, Luo J. The PIN-FORMED Auxin Efflux Carriers in Plants. Int J Mol Sci 2018; 19:E2759. [PMID: 30223430 PMCID: PMC6164769 DOI: 10.3390/ijms19092759] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 09/11/2018] [Accepted: 09/12/2018] [Indexed: 12/14/2022] Open
Abstract
Auxin plays crucial roles in multiple developmental processes, such as embryogenesis, organogenesis, cell determination and division, as well as tropic responses. These processes are finely coordinated by the auxin, which requires the polar distribution of auxin within tissues and cells. The intercellular directionality of auxin flow is closely related to the asymmetric subcellular location of PIN-FORMED (PIN) auxin efflux transporters. All PIN proteins have a conserved structure with a central hydrophilic loop domain, which harbors several phosphosites targeted by a set of protein kinases. The activities of PIN proteins are finely regulated by diverse endogenous and exogenous stimuli at multiple layers-including transcriptional and epigenetic levels, post-transcriptional modifications, subcellular trafficking, as well as PINs' recycling and turnover-to facilitate the developmental processes in an auxin gradient-dependent manner. Here, the recent advances in the structure, evolution, regulation and functions of PIN proteins in plants will be discussed. The information provided by this review will shed new light on the asymmetric auxin-distribution-dependent development processes mediated by PIN transporters in plants.
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Affiliation(s)
- Jing-Jing Zhou
- College of Horticulture and Forestry Science, Hubei Engineering Technology Research Center for Forestry Information, Huazhong Agricultural University, Wuhan 430070, China.
| | - Jie Luo
- College of Horticulture and Forestry Science, Hubei Engineering Technology Research Center for Forestry Information, Huazhong Agricultural University, Wuhan 430070, China.
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