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Mohammed S, El-Sheekh MM, Hamed Aly S, Al-Harbi M, Elkelish A, Nagah A. Inductive role of the brown alga Sargassum polycystum on growth and biosynthesis of imperative metabolites and antioxidants of two crop plants. FRONTIERS IN PLANT SCIENCE 2023; 14:1136325. [PMID: 36925755 PMCID: PMC10013155 DOI: 10.3389/fpls.2023.1136325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 02/09/2023] [Indexed: 06/18/2023]
Abstract
The potential of macroalgae as biostimulants in agriculture was proved worthy. Vicia faba and Helianthus annuus are socioeconomic crops owing to their increasing demand worldwide. In this work, we investigated the energetic role of seed presoaking and irrigation by the brown seaweed, Sargassum polycystum aqueous extract (SAE) on certain germination and growth traits, photosynthetic pigments, carbohydrates, phenolics, flavonoids, and the total antioxidant activity. Compared to the control plants, our consequences revealed that seeds that received the SAE improved all the germination and growth criteria for both crop plants. Furthermore, the SAE significantly increased the carotenoids, total photosynthetic pigments, and total carbohydrates by (14%, 7%, and 41%) for V. faba and (17%, 17%, and 38%) for H. annuus, respectively. Phenolics and flavonoids were significantly induced in Vicia but slightly promoted in Helianthu plants, whereas the total antioxidant activity in both crops non significantly elevated. Even though The NPK contents were significantly stimulated by the SAE in Vicia plants, the effect was different in Helianthus, where only nitrogen content was significantly enhanced, whereas phosphorus and potassium showed little enhancement. Thus, the SAE treatment is one of the superlative sustainable strategies for food, feed, and as excellent plant conditioner.
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Affiliation(s)
- Soha Mohammed
- Botany and Microbiology Department, Faculty of Science, Banha University, Benha, Egypt
| | | | - Saadia Hamed Aly
- Botany and Microbiology Department, Faculty of Science, Banha University, Benha, Egypt
| | - Maha Al-Harbi
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Amr Elkelish
- Biology Department, College of Science, Imam Mohammad ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia
- Botany and Microbiology Department, Faculty of Science, Suez Canal University, Ismailia, Egypt
| | - Aziza Nagah
- Botany and Microbiology Department, Faculty of Science, Banha University, Benha, Egypt
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Durán AG, Calle JM, Butrón D, Pérez AJ, Macías FA, Simonet AM. Steroidal Saponins with Plant Growth Stimulation Effects; Yucca schidigera as a Commercial Source. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11233378. [PMID: 36501417 PMCID: PMC9740418 DOI: 10.3390/plants11233378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/25/2022] [Accepted: 12/01/2022] [Indexed: 05/26/2023]
Abstract
Plant growth-stimulation bioactivity of triterpenoid saponins is well known, especially for oleanane-type compounds. Nevertheless, a few phytotoxicity bioassays performed on some steroidal saponins have shown hormesis profiles and growth stimulation on Lactuca sativa roots. The focus of the work described here was on the use of the wheat coleoptile bioassay to evaluate plant growth stimulation, and on the search for a commercially available source of active saponins by bio-guided fractionation strategy. Selected saponins were tested and a cluster analysis showed that those saponins with a sugar chain of more than five units had a hormesis profile, while saponins with growth enhancement had fewer sugar residues. Two saponins showed similar activity to the positive control, namely the phytohormone indole-3-butyric acid (IBA). As a potential source of these metabolites, a commercial extract of Yucca schidigera used as a fertilizer was selected. Bio-guided fractionation led to the identification of two fractions of defined composition and these showed stimulation values similar to the positive control. It was observed that the presence of a carbonyl group at C-12 on the aglycone skeleton led to improved activity. A saponin-rich fraction from Y. schidigera could be proposed to enhance crop quality and production.
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Affiliation(s)
- Alexandra G. Durán
- Allelopathy Group, Department of Organic Chemistry, Campus de Excelencia Internacional (ceiA3), Institute of Biomolecules (INBIO), School of Science, University of Cádiz, C/República Saharaui 7, 11510 Cádiz, Spain
| | - Juan M. Calle
- Allelopathy Group, Department of Organic Chemistry, Campus de Excelencia Internacional (ceiA3), Institute of Biomolecules (INBIO), School of Science, University of Cádiz, C/República Saharaui 7, 11510 Cádiz, Spain
| | - Davinia Butrón
- Allelopathy Group, Department of Organic Chemistry, Campus de Excelencia Internacional (ceiA3), Institute of Biomolecules (INBIO), School of Science, University of Cádiz, C/República Saharaui 7, 11510 Cádiz, Spain
| | - Andy J. Pérez
- Departamento de Análisis Instrumental, Facultad de Farmacia, Universidad de Concepción, Concepción 4070386, Chile
| | - Francisco A. Macías
- Allelopathy Group, Department of Organic Chemistry, Campus de Excelencia Internacional (ceiA3), Institute of Biomolecules (INBIO), School of Science, University of Cádiz, C/República Saharaui 7, 11510 Cádiz, Spain
| | - Ana M. Simonet
- Allelopathy Group, Department of Organic Chemistry, Campus de Excelencia Internacional (ceiA3), Institute of Biomolecules (INBIO), School of Science, University of Cádiz, C/República Saharaui 7, 11510 Cádiz, Spain
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3
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Yang Y, Liu X, Wang X, Lv W, Liu X, Ma L, Fu H, Song S, Lei X. Screening of protonstatin-1 (PS-1) analogs for improved inhibitors of plant plasma membrane H +-ATPase activity. FRONTIERS IN PLANT SCIENCE 2022; 13:973471. [PMID: 36311099 PMCID: PMC9597486 DOI: 10.3389/fpls.2022.973471] [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: 06/20/2022] [Accepted: 09/01/2022] [Indexed: 06/16/2023]
Abstract
We previously identified protonstatin-1 (PS-1) as a selective inhibitor of plasma membrane H+-ATPase (PM H+-ATPase) activity and used it as a tool to validate the chemiosmotic model for polar auxin transport. Here, to obtain compounds with higher affinity than PS-1 for PM H+-ATPase, we synthesized 34 PS-1 analogs and examined their ability to inhibit PM H+-ATPase activity. The 34 analogs showed varying inhibitory effects on the activity of this enzyme. The strongest effect was observed for the small molecule PS-2, which was approximately five times stronger than PS-1. Compared to PS-1, PS-2 was also a stronger inhibitor of auxin uptake as well as acropetal and basipetal polar auxin transport in Arabidopsis thaliana seedlings. Because PS-2 is a more potent inhibitor of PM H+-ATPase than PS-1, we believe that this compound could be used as a tool to study the functions of this key plant enzyme.
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Affiliation(s)
- Yongqing Yang
- College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xiaohui Liu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Xin Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Wanjia Lv
- College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xiao Liu
- College of Biological Sciences, China Agricultural University, Beijing, China
| | - Liang Ma
- College of Biological Sciences, China Agricultural University, Beijing, China
| | - Haiqi Fu
- College of Biological Sciences, China Agricultural University, Beijing, China
| | - Shu Song
- College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xiaoguang Lei
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
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4
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Yang Y, Liu X, Guo W, Liu W, Shao W, Zhao J, Li J, Dong Q, Ma L, He Q, Li Y, Han J, Lei X. Testing the polar auxin transport model with a selective plasma membrane H + -ATPase inhibitor. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:1229-1245. [PMID: 35352470 DOI: 10.1111/jipb.13256] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 03/24/2022] [Indexed: 06/14/2023]
Abstract
Auxin is unique among plant hormones in that its function requires polarized transport across plant cells. A chemiosmotic model was proposed to explain how polar auxin transport is derived by the H+ gradient across the plasma membrane (PM) established by PM H+ -adenosine triphosphatases (ATPases). However, a classical genetic approach by mutations in PM H+ -ATPase members did not result in the ablation of polar auxin distribution, possibly due to functional redundancy in this gene family. To confirm the crucial role of PM H+ -ATPases in the polar auxin transport model, we employed a chemical genetic approach. Through a chemical screen, we identified protonstatin-1 (PS-1), a selective small-molecule inhibitor of PM H+ -ATPase activity that inhibits auxin transport. Assays with transgenic plants and yeast strains showed that the activity of PM H+ -ATPases affects auxin uptake as well as acropetal and basipetal polar auxin transport. We propose that PS-1 can be used as a tool to interrogate the function of PM H+ -ATPases. Our results support the chemiosmotic model in which PM H+ -ATPase itself plays a fundamental role in polar auxin transport.
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Affiliation(s)
- Yongqing Yang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Xiaohui Liu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Wei Guo
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Wei Liu
- Department of Dermatology, Peking University First Hospital, Beijing, 100034, China
| | - Wei Shao
- Iomics Biosciences Inc., Beijing, 100102, China
| | - Jun Zhao
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Junhong Li
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Qing Dong
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Liang Ma
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Qun He
- College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yingzhang Li
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jianyong Han
- College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Xiaoguang Lei
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
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5
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Ashraf MA, Umetsu K, Ponomarenko O, Saito M, Aslam M, Antipova O, Dolgova N, Kiani CD, Nehzati S, Tanoi K, Minegishi K, Nagatsu K, Kamiya T, Fujiwara T, Luschnig C, Tanino K, Pickering I, George GN, Rahman A. PIN FORMED 2 Modulates the Transport of Arsenite in Arabidopsis thaliana. PLANT COMMUNICATIONS 2020; 1:100009. [PMID: 33404549 PMCID: PMC7747963 DOI: 10.1016/j.xplc.2019.100009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 10/15/2019] [Accepted: 11/18/2019] [Indexed: 05/23/2023]
Abstract
Arsenic contamination is a major environmental issue, as it may lead to serious health hazard. The reduced trivalent form of inorganic arsenic, arsenite, is in general more toxic to plants compared with the fully oxidized pentavalent arsenate. The uptake of arsenite in plants has been shown to be mediated through a large subfamily of plant aquaglyceroporins, nodulin 26-like intrinsic proteins (NIPs). However, the efflux mechanisms, as well as the mechanism of arsenite-induced root growth inhibition, remain poorly understood. Using molecular physiology, synchrotron imaging, and root transport assay approaches, we show that the cellular transport of trivalent arsenicals in Arabidopsis thaliana is strongly modulated by PIN FORMED 2 (PIN2) auxin efflux transporter. Root transport assay using radioactive arsenite, X-ray fluorescence imaging (XFI) coupled with X-ray absorption spectroscopy (XAS), and inductively coupled plasma mass spectrometry analysis revealed that pin2 plants accumulate higher concentrations of arsenite in roots compared with the wild-type. At the cellular level, arsenite specifically targets intracellular sorting of PIN2 and thereby alters the cellular auxin homeostasis. Consistently, loss of PIN2 function results in arsenite hypersensitivity in roots. XFI coupled with XAS further revealed that loss of PIN2 function results in specific accumulation of arsenical species, but not the other metals such as iron, zinc, or calcium in the root tip. Collectively, these results suggest that PIN2 likely functions as an arsenite efflux transporter for the distribution of arsenical species in planta.
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Affiliation(s)
- Mohammad Arif Ashraf
- United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate, Japan
| | - Kana Umetsu
- Department of Plant Bio Sciences, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
| | - Olena Ponomarenko
- Molecular and Environmental Science Research Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| | - Michiko Saito
- Department of Plant Bio Sciences, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
| | - Mohammad Aslam
- Department of Plant Bio Sciences, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
| | - Olga Antipova
- Argonne National Lab, Advanced Photon Source, XSD-MIC, Lemont, IL, USA
| | - Natalia Dolgova
- Molecular and Environmental Science Research Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| | - Cheyenne D. Kiani
- Molecular and Environmental Science Research Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| | - Susan Nehzati
- Molecular and Environmental Science Research Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| | - Keitaro Tanoi
- Isotope Facility for Agricultural Education and Research, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Katsuyuki Minegishi
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Inage, Chiba, Japan
| | - Kotaro Nagatsu
- Department of Radiopharmaceuticals Development, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Inage, Chiba, Japan
| | - Takehiro Kamiya
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Toru Fujiwara
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Christian Luschnig
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, 1180 Wien, Austria
| | - Karen Tanino
- Department of Plant Sciences, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK, Canada
| | - Ingrid Pickering
- Molecular and Environmental Science Research Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| | - Graham N. George
- Molecular and Environmental Science Research Group, Department of Geological Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| | - Abidur Rahman
- United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate, Japan
- Department of Plant Bio Sciences, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
- Agri-Innovation Center, Iwate University, Morioka, Iwate, Japan
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6
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Wang Y, Ji Y, Fu Y, Guo H. Ethylene-induced microtubule reorientation is essential for fast inhibition of root elongation in Arabidopsis. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2018; 60:864-877. [PMID: 29752856 DOI: 10.1111/jipb.12666] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 05/09/2018] [Indexed: 05/22/2023]
Abstract
Microtubule reorientation is a long-standing observation that has been implicated in regulating the inhibitory effect of ethylene on axial elongation of plant cells. However, the signaling mechanism underlying ethylene-induced microtubule reorientation has remained elusive. Here, we reveal, by live confocal imaging and kinetic root elongation assays, that the time courses of ethylene-induced microtubule reorientation and root elongation inhibition are highly correlated, and that microtubule reorientation is required for the full responsiveness of root elongation to ethylene treatment. Our genetic analysis demonstrated that the effect of ethylene on microtubule orientation and root elongation is mainly transduced through the canonical linear ethylene signaling pathway. By using pharmacological and genetic analyses, we demonstrate further that the TIR1/AFBs-Aux/IAAs-ARFs auxin signaling pathway, but not the ABP1-ROP6-RIC1 auxin signaling branch, is essential for ethylene-induced microtubule reorientation and root elongation inhibition. Together, these findings offer evidence for the functional significance and elucidate the signaling mechanism for ethylene-induced microtubule reorientation in fast root elongation inhibition in Arabidopsis.
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Affiliation(s)
- Yichuan Wang
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yusi Ji
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
| | - Ying Fu
- State Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Hongwei Guo
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
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7
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Radhakrishnan R, Alqarawi AA, Abd Allah EF. Bioherbicides: Current knowledge on weed control mechanism. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 158:131-138. [PMID: 29677595 DOI: 10.1016/j.ecoenv.2018.04.018] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 04/03/2018] [Accepted: 04/07/2018] [Indexed: 05/27/2023]
Abstract
Weed control is a challenging event during crop cultivation. Integrated management, including the application of bioherbicides, is an emerging method for weed control in sustainable agriculture. Plant extracts, allelochemicals and some microbes are utilized as bioherbicides to control weed populations. Bioherbicides based on plants and microbes inhibit the germination and growth of weeds; however,few studies conducted in weed physiology. This review ascribes the current knowledge of the physiological changes in weeds that occur during the exposure to bioherbicides. Plant extracts or metabolites are absorbed by weed seeds, which initiates damage to the cell membrane, DNA, mitosis, amylase activity and other biochemical processes and delays or inhibits seed germination. The growth of weeds is also retarded due to low rates of root-cell division, nutrient uptake, photosynthetic pigment synthesis, and plant growth hormone synthesis, while the productions of reactive oxygen species (ROS) and stress-mediated hormones increase, including irregular antioxidant activity. However, lytic enzymes and toxic substances secreted from microbes degrade the weed seed coat and utilize the endosperm for survival, which inhibits seed germination. The microbes grow through the intercellular spaces to reach the root core, and the deposition of toxins in the cells affects cell division and cellular functions. Some of the metabolites of deleterious microbes cause disease, necrosis and chlorosis,which inhibit the germination and growth of weed seeds by suppressing photosynthesis and gibberellin activities and enhancing ROS, abscisic acid and ethylene. This review explains the effects of bioherbicides (derived from plants and microbes) on weed-plant physiology to elucidate their modes of action.
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Affiliation(s)
| | - Abdulaziz A Alqarawi
- Plant Production Department, College of Food and Agricultural Sciences, King Saud University, P.O. Box. 2460, Riyadh 11451, Saudi Arabia
| | - Elsayed Fathi Abd Allah
- Plant Production Department, College of Food and Agricultural Sciences, King Saud University, P.O. Box. 2460, Riyadh 11451, Saudi Arabia.
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8
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Staswick P, Rowe M, Spalding EP, Splitt BL. Jasmonoyl-L-Tryptophan Disrupts IAA Activity through the AUX1 Auxin Permease. FRONTIERS IN PLANT SCIENCE 2017; 8:736. [PMID: 28533791 PMCID: PMC5420569 DOI: 10.3389/fpls.2017.00736] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 04/20/2017] [Indexed: 05/29/2023]
Abstract
Amide-linked conjugates between tryptophan (Trp) and jasmonic (JA) or indole-3-acetic (IAA) acids interfered with gravitropism and other auxin-dependent activities in Arabidopsis, but the mechanism was unclear. To identify structural features necessary for activity several additional Trp conjugates were synthesized. The phenylacetic acid (PAA) conjugate was active, while several others were not. Common features of active conjugates is that they have ring structures that are linked to Trp through an acetic acid side chain, while longer or shorter linkages are inactive or less active. A dominant mutant, called tryptophan conjugate response1-D that is insensitive to JA-Trp, but still sensitive to other active conjugates, was identified and the defect was found to be a substitution of Asn for Asp456 in the C-terminal domain of the IAA cellular permease AUX1. Mutant seedling primary root growth in the absence of added conjugate was 15% less than WT, but otherwise plant phenotype appeared normal. These results suggest that JA-Trp disrupts AUX1 activity, but that endogenous JA-Trp has only a minor role in regulating plant growth. In contrast with IAA- and JA-Trp, which are present at <2 pmole g-1 FW, PAA-Trp was found at about 30 pmole g-1 FW. The latter, or other undiscovered Trp conjugates, may still have important endogenous roles, possibly helping to coordinate other pathways with auxin response.
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Affiliation(s)
- Paul Staswick
- Department of Agronomy and Horticulture, University of Nebraska–Lincoln, LincolnNE, USA
| | - Martha Rowe
- Department of Agronomy and Horticulture, University of Nebraska–Lincoln, LincolnNE, USA
| | - Edgar P. Spalding
- Department of Botany, University of Wisconsin–Madison, MadisonWI, USA
| | - Bessie L. Splitt
- Department of Botany, University of Wisconsin–Madison, MadisonWI, USA
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9
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Takahashi M, Umetsu K, Oono Y, Higaki T, Blancaflor EB, Rahman A. Small acidic protein 1 and SCF TIR1 ubiquitin proteasome pathway act in concert to induce 2,4-dichlorophenoxyacetic acid-mediated alteration of actin in Arabidopsis roots. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 89:940-956. [PMID: 27885735 DOI: 10.1111/tpj.13433] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 11/09/2016] [Accepted: 11/14/2016] [Indexed: 06/06/2023]
Abstract
2,4-Dichlorophenoxyacetic acid (2,4-D), a functional analogue of auxin, is used as an exogenous source of auxin as it evokes physiological responses like the endogenous auxin, indole-3-acetic acid (IAA). Previous molecular analyses of the auxin response pathway revealed that IAA and 2,4-D share a common mode of action to elicit downstream physiological responses. However, recent findings with 2,4-D-specific mutants suggested that 2,4-D and IAA might also use distinct pathways to modulate root growth in Arabidopsis. Using genetic and cellular approaches, we demonstrate that the distinct effects of 2,4-D and IAA on actin filament organization partly dictate the differential responses of roots to these two auxin analogues. 2,4-D but not IAA altered the actin structure in long-term and short-term assays. Analysis of the 2,4-D-specific mutant aar1-1 revealed that small acidic protein 1 (SMAP1) functions positively to facilitate the 2,4-D-induced depolymerization of actin. The ubiquitin proteasome mutants tir1-1 and axr1-12, which show enhanced resistance to 2,4-D compared with IAA for inhibition of root growth, were also found to have less disrupted actin filament networks after 2,4-D exposure. Consistently, a chemical inhibitor of the ubiquitin proteasome pathway mitigated the disrupting effects of 2,4-D on the organization of actin filaments. Roots of the double mutant aar1-1 tir1-1 also showed enhanced resistance to 2,4-D-induced inhibition of root growth and actin degradation compared with their respective parental lines. Collectively, these results suggest that the effects of 2,4-D on actin filament organization and root growth are mediated through synergistic interactions between SMAP1 and SCFTIR1 ubiquitin proteasome components.
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Affiliation(s)
- Maho Takahashi
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, 020-8550, Japan
| | - Kana Umetsu
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, 020-8550, Japan
| | - Yutaka Oono
- Department of Radiation-Applied Biology, Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology (QST), Takasaki, 370-1292, Japan
| | - Takumi Higaki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-8562, Japan
| | - Elison B Blancaflor
- Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, OK, 73401, USA
| | - Abidur Rahman
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, 020-8550, Japan
- Department of Plant Bio Sciences, Faculty of Agriculture, Iwate University, Morioka, 020-8550, Japan
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10
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Klíma P, Laňková M, Zažímalová E. Inhibitors of plant hormone transport. PROTOPLASMA 2016; 253:1391-1404. [PMID: 26494150 DOI: 10.1007/s00709-015-0897-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 10/09/2015] [Indexed: 06/05/2023]
Abstract
Here we present an overview of what is known about endogenous plant compounds that act as inhibitors of hormonal transport processes in plants, about their identity and mechanism of action. We have also summarized commonly and less commonly used compounds of non-plant origin and synthetic drugs that show at least partial 'specificity' to transport or transporters of particular phytohormones. Our main attention is focused on the inhibitors of auxin transport. The urgent need to understand precisely the molecular mechanism of action of these inhibitors is highlighted.
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Affiliation(s)
- Petr Klíma
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojová 263, 165 02, Prague 6, Czech Republic
| | - Martina Laňková
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojová 263, 165 02, Prague 6, Czech Republic
| | - Eva Zažímalová
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojová 263, 165 02, Prague 6, Czech Republic.
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11
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Belz RG. Investigating a Potential Auxin-Related Mode of Hormetic/Inhibitory Action of the Phytotoxin Parthenin. J Chem Ecol 2016; 42:71-83. [PMID: 26686984 DOI: 10.1007/s10886-015-0662-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 11/12/2015] [Accepted: 12/03/2015] [Indexed: 12/22/2022]
Abstract
Parthenin is a metabolite of Parthenium hysterophorus and is believed to contribute to the weed's invasiveness via allelopathy. Despite the potential of parthenin to suppress competitors, low doses stimulate plant growth. This biphasic action was hypothesized to be auxin-like and, therefore, an auxin-related mode of parthenin action was investigated using two approaches: joint action experiments with Lactuca sativa, and dose-response experiments with auxin/antiauxin-resistant Arabidopsis thaliana genotypes. The joint action approach comprised binary mixtures of subinhibitory doses of the auxin 3-indoleacetic acid (IAA) mixed with parthenin or one of three reference compounds [indole-3-butyric acid (IBA), 2,3,5-triiodobenzoic acid (TIBA), 2-(p-chlorophenoxy)-2-methylpropionic acid (PCIB)]. The reference compounds significantly interacted with IAA at all doses, but parthenin interacted only at low doses indicating that parthenin hormesis may be auxin-related, in contrast to its inhibitory action. The genetic approach investigated the response of four auxin/antiauxin-resistant mutants and a wildtype to parthenin or two reference compounds (IAA, PCIB). The responses of mutant plants to the reference compounds confirmed previous reports, but differed from the responses observed for parthenin. Parthenin stimulated and inhibited all mutants independent of resistance. This provided no indication for an auxin-related action of parthenin. Therefore, the hypothesis of an auxin-related inhibitory action of parthenin was rejected in two independent experimental approaches, while the hypothesis of an auxin-related stimulatory effect could not be rejected.
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Affiliation(s)
- Regina G Belz
- Agroecology Unit, Hans-Ruthenberg-Institute, University of Hohenheim, Stuttgart, 70593, Germany.
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12
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Moses T, Papadopoulou KK, Osbourn A. Metabolic and functional diversity of saponins, biosynthetic intermediates and semi-synthetic derivatives. Crit Rev Biochem Mol Biol 2014; 49:439-62. [PMID: 25286183 PMCID: PMC4266039 DOI: 10.3109/10409238.2014.953628] [Citation(s) in RCA: 239] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 08/01/2014] [Accepted: 08/07/2014] [Indexed: 01/11/2023]
Abstract
Saponins are widely distributed plant natural products with vast structural and functional diversity. They are typically composed of a hydrophobic aglycone, which is extensively decorated with functional groups prior to the addition of hydrophilic sugar moieties, to result in surface-active amphipathic compounds. The saponins are broadly classified as triterpenoids, steroids or steroidal glycoalkaloids, based on the aglycone structure from which they are derived. The saponins and their biosynthetic intermediates display a variety of biological activities of interest to the pharmaceutical, cosmetic and food sectors. Although their relevance in industrial applications has long been recognized, their role in plants is underexplored. Recent research on modulating native pathway flux in saponin biosynthesis has demonstrated the roles of saponins and their biosynthetic intermediates in plant growth and development. Here, we review the literature on the effects of these molecules on plant physiology, which collectively implicate them in plant primary processes. The industrial uses and potential of saponins are discussed with respect to structure and activity, highlighting the undoubted value of these molecules as therapeutics.
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Affiliation(s)
- Tessa Moses
- Department of Metabolic Biology, John Innes CentreColney Lane, NorwichUK
| | | | - Anne Osbourn
- Department of Metabolic Biology, John Innes CentreColney Lane, NorwichUK
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13
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Krishnamurthy P, Tsukamoto C, Takahashi Y, Hongo Y, Singh RJ, Lee JD, Chung G. Comparison of saponin composition and content in wild soybean (Glycine soja Sieb. and Zucc.) before and after germination. Biosci Biotechnol Biochem 2014; 78:1988-96. [PMID: 25127168 DOI: 10.1080/09168451.2014.946389] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Eight wild soybean accessions with different saponin phenotypes were used to examine saponin composition and relative saponin quantity in various tissues of mature seeds and two-week-old seedlings by LC-PDA/MS/MS. Saponin composition and content were varied according to tissues and accessions. The average total saponin concentration in 1 g mature dry seeds of wild soybean was 16.08 ± 3.13 μmol. In two-week-old seedlings, produced from 1 g mature seeds, it was 27.94 ± 6.52 μmol. Group A saponins were highly concentrated in seed hypocotyl (4.04 ± 0.71 μmol). High concentration of DDMP saponins (7.37 ± 5.22 μmol) and Sg-6 saponins (2.19 ± 0.59 μmol) was found in cotyledonary leaf. In seedlings, the amounts of group A and Sg-6 saponins reduced 2.3- and 1.3-folds, respectively, while DDMP + B + E saponins increased 2.5-fold than those of mature seeds. Our findings show that the group A and Sg-6 saponins in mature seeds were degraded and/or translocated by germination whereas DDMP saponins were newly synthesized.
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14
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Hanzawa T, Shibasaki K, Numata T, Kawamura Y, Gaude T, Rahman A. Cellular auxin homeostasis under high temperature is regulated through a sorting NEXIN1-dependent endosomal trafficking pathway. THE PLANT CELL 2013; 25:3424-33. [PMID: 24003052 PMCID: PMC3809541 DOI: 10.1105/tpc.113.115881] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 08/11/2013] [Accepted: 08/19/2013] [Indexed: 05/19/2023]
Abstract
High-temperature-mediated adaptation in plant architecture is linked to the increased synthesis of the phytohormone auxin, which alters cellular auxin homeostasis. The auxin gradient, modulated by cellular auxin homeostasis, plays an important role in regulating the developmental fate of plant organs. Although the signaling mechanism that integrates auxin and high temperature is relatively well understood, the cellular auxin homeostasis mechanism under high temperature is largely unknown. Using the Arabidopsis thaliana root as a model, we demonstrate that under high temperature, roots counterbalance the elevated level of intracellular auxin by promoting shootward auxin efflux in a PIN-FORMED2 (PIN2)-dependent manner. Further analyses revealed that high temperature selectively promotes the retrieval of PIN2 from late endosomes and sorts them to the plasma membrane through an endosomal trafficking pathway dependent on SORTING NEXIN1. Our results demonstrate that recycling endosomal pathway plays an important role in facilitating plants adaptation to increased temperature.
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Affiliation(s)
- Taiki Hanzawa
- Cryobiofrontier Research Centre, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Kyohei Shibasaki
- Cryobiofrontier Research Centre, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
- Plant Biology Division, Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401
| | - Takahiro Numata
- Cryobiofrontier Research Centre, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Yukio Kawamura
- Cryobiofrontier Research Centre, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Thierry Gaude
- Reproduction et Développement des Plantes, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Structure Fédérative de Recherche BioSciences Gerland-Lyon Sud, Ecole Normale Supérieure Lyon, 69364 Lyon cedex 07, France
| | - Abidur Rahman
- Cryobiofrontier Research Centre, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
- Address correspondence to
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15
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Graña E, Sotelo T, Díaz-Tielas C, Araniti F, Krasuska U, Bogatek R, Reigosa MJ, Sánchez-Moreiras AM. Citral induces auxin and ethylene-mediated malformations and arrests cell division in Arabidopsis thaliana roots. J Chem Ecol 2013; 39:271-82. [PMID: 23389342 DOI: 10.1007/s10886-013-0250-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 01/18/2013] [Accepted: 01/24/2013] [Indexed: 10/27/2022]
Abstract
Citral is a linear monoterpene which is present, as a volatile component, in the essential oil of several different aromatic plants. Previous studies have demonstrated the ability of citral to alter the mitotic microtubules of plant cells, especially at low concentrations. The changes to the microtubules may be due to the compound acting directly on the treated root and coleoptile cells or to indirect action through certain phytohormones. This study, performed in Arabidopsis thaliana, analysed the short-term effects of citral on the auxin content and mitotic cells, and the long-term effects of these alterations on root development and ethylene levels. The results of this study show that citral alters auxin content and cell division and has a strong long-term disorganising effect on cell ultra-structure in A. thaliana seedlings. Its effects on cell division, the thickening of the cell wall, the reduction in intercellular communication, and the absence of root hairs confirm that citral is a strong phytotoxic compound, which has persistent effects on root development.
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Affiliation(s)
- E Graña
- Department of Plant Biology and Soil Science, University of Vigo, Campus Lagoas-Marcosende s/n, 36310 Vigo, Spain
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16
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Yu J, Wen CK. Arabidopsis aux1rcr1 mutation alters AUXIN RESISTANT1 targeting and prevents expression of the auxin reporter DR5:GUS in the root apex. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:921-33. [PMID: 23293348 PMCID: PMC3580809 DOI: 10.1093/jxb/ers371] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Multilevel interactions of the plant hormones ethylene and auxin coordinately and synergistically regulate many aspects of plant growth and development. This study isolated the AUXIN RESISTANT1 (AUX1) allele aux1(rcr1) (RCR1 for REVERSING CTR1-10 ROOT1) that suppressed the root growth inhibition conferred by the constitutive ethylene-response constitutive triple response1-10 (ctr1-10) allele. The aux1(rcr1) mutation resulted from an L126F substitution at loop 2 of the plasma membrane-associated auxin influx carrier protein AUX1. aux1(rcr1) and the T-DNA insertion mutant aux1-T were both defective in auxin transport and many aspects of the auxin response. Unexpectedly, expression of the auxin-response reporter DR5:GUS in the root apex was substantially prevented by the aux1(rcr1) but not the aux1-T mutation, even in the presence of the wild-type AUX1 allele. Following treatment with the synthetic auxin 1-naphthaleneacetic acid (NAA), DR5:GUS expression in aux1(rcr1) and aux1-T occurred mainly in the root apex and mature zone. NAA-induced DR5:GUS expression in the root apex was markedly prevented by ethylene in genotypes with aux1(rcr1) but not in aux1-T genotypes and the wild type. The effect of aux1(rcr1) on DR5:GUS expression seemed to be associated with AUX1-expressing domains. Green fluorescence protein-fused aux1(rcr1) was localized in the cytoplasm and probably not to the plasma membrane, indicating important roles of the Lys(126) residue at loop 2 in AUX1 targeting. The possible effects of aux1(rcr1) on DR5:GUS expression are discussed.
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Affiliation(s)
- Jing Yu
- National Key Laboratory of Plant Molecular Genetics and National Center for Plant Gene Research (Shanghai), Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
| | - Chi-Kuang Wen
- National Key Laboratory of Plant Molecular Genetics and National Center for Plant Gene Research (Shanghai), Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
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17
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Scognamiglio M, D'Abrosca B, Fiumano V, Chambery A, Severino V, Tsafantakis N, Pacifico S, Esposito A, Fiorentino A. Oleanane saponins from Bellis sylvestris Cyr. and evaluation of their phytotoxicity on Aegilops geniculata Roth. PHYTOCHEMISTRY 2012; 84:125-134. [PMID: 22959224 DOI: 10.1016/j.phytochem.2012.08.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 07/31/2012] [Accepted: 08/11/2012] [Indexed: 06/01/2023]
Abstract
Six oleanane saponins were isolated for the first time from leaves of Bellis sylvestris Cyr., the southern daisy. Their structures were established by the extensive use of 2D-NMR experiments, including COSY, TOCSY, NOESY, HSQC, HMBC, CIGAR, H2BC, and HSQC-TOCSY, along with Q-TOF HRMS² analysis. All of the compounds are constituted by bayogenin as aglycone, and characterized by the presence of an oligosaccharide moiety, consisting of two to four sugar unities esterified at the C-28 carboxyl carbon. One of the isolated compounds is a bisdesmoside containing an additional sugar moiety at the C-3 carbon. The phytotoxic activity assayed against Aegilops geniculata Roth., a coexisting test species, has been evaluated revealing that all the compounds, at the highest concentrations, showed strong phytotoxicity against the leaf development.
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Affiliation(s)
- Monica Scognamiglio
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of Naples, via Vivaldi 43, I-81100 Caserta, Italy
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18
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Abstract
Saponins are one of the most numerous and diverse groups of plant natural products. They serve a range of ecological roles including plant defence against disease and herbivores and possibly as allelopathic agents in competitive interactions between plants. Some saponins are also important pharmaceuticals, and the underexplored biodiversity of plant saponins is likely to prove to be a vital resource for future drug discovery. The biological activity of saponins is normally attributed to the amphipathic properties of these molecules, which consist of a hydrophobic triterpene or sterol backbone and a hydrophilic carbohydrate chain, although some saponins are known to have potent biological activities that are dependent on other aspects of their structure. This chapter will focus on the biological activity and the synthesis of some of the best-studied examples of plant saponins and on recent developments in the identification of the genes and enzymes responsible for saponin synthesis.
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19
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Hošek P, Kubeš M, Laňková M, Dobrev PI, Klíma P, Kohoutová M, Petrášek J, Hoyerová K, Jiřina M, Zažímalová E. Auxin transport at cellular level: new insights supported by mathematical modelling. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:3815-27. [PMID: 22438304 PMCID: PMC3388834 DOI: 10.1093/jxb/ers074] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Revised: 02/01/2012] [Accepted: 02/16/2012] [Indexed: 05/20/2023]
Abstract
The molecular basis of cellular auxin transport is still not fully understood. Although a number of carriers have been identified and proved to be involved in auxin transport, their regulation and possible activity of as yet unknown transporters remain unclear. Nevertheless, using single-cell-based systems it is possible to track the course of auxin accumulation inside cells and to specify and quantify some auxin transport parameters. The synthetic auxins 2,4-dichlorophenoxyacetic acid (2,4-D) and naphthalene-1-acetic acid (NAA) are generally considered to be suitable tools for auxin transport studies because they are transported specifically via either auxin influx or efflux carriers, respectively. Our results indicate that NAA can be metabolized rapidly in tobacco BY-2 cells. The predominant metabolite has been identified as NAA glucosyl ester and it is shown that all NAA metabolites were retained inside the cells. This implies that the transport efficiency of auxin efflux transporters is higher than previously assumed. By contrast, the metabolism of 2,4-D remained fairly weak. Moreover, using data on the accumulation of 2,4-D measured in the presence of auxin transport inhibitors, it is shown that 2,4-D is also transported by efflux carriers. These results suggest that 2,4-D is a promising tool for determining both auxin influx and efflux activities. Based on the accumulation data, a mathematical model of 2,4-D transport at a single-cell level is proposed. Optimization of the model provides estimates of crucial transport parameters and, together with its validation by successfully predicting the course of 2,4-D accumulation, it confirms the consistency of the present concept of cellular auxin transport.
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Affiliation(s)
- Petr Hošek
- Institute of Experimental Botany, the Academy of Sciences of the Czech Republic, Rozvojová 263, 165 02 Prague 6, Czech Republic
- Department of Biomedical Informatics, Faculty of Biomedical Engineering, Czech Technical University in Prague, Nám. Sítná 3105, 272 01 Kladno 2, Czech Republic
| | - Martin Kubeš
- Institute of Experimental Botany, the Academy of Sciences of the Czech Republic, Rozvojová 263, 165 02 Prague 6, Czech Republic
| | - Martina Laňková
- Institute of Experimental Botany, the Academy of Sciences of the Czech Republic, Rozvojová 263, 165 02 Prague 6, Czech Republic
| | - Petre I. Dobrev
- Institute of Experimental Botany, the Academy of Sciences of the Czech Republic, Rozvojová 263, 165 02 Prague 6, Czech Republic
| | - Petr Klíma
- Institute of Experimental Botany, the Academy of Sciences of the Czech Republic, Rozvojová 263, 165 02 Prague 6, Czech Republic
| | - Milada Kohoutová
- Department of Biomedical Informatics, Faculty of Biomedical Engineering, Czech Technical University in Prague, Nám. Sítná 3105, 272 01 Kladno 2, Czech Republic
| | - Jan Petrášek
- Institute of Experimental Botany, the Academy of Sciences of the Czech Republic, Rozvojová 263, 165 02 Prague 6, Czech Republic
| | - Klára Hoyerová
- Institute of Experimental Botany, the Academy of Sciences of the Czech Republic, Rozvojová 263, 165 02 Prague 6, Czech Republic
| | - Marcel Jiřina
- Department of Biomedical Informatics, Faculty of Biomedical Engineering, Czech Technical University in Prague, Nám. Sítná 3105, 272 01 Kladno 2, Czech Republic
| | - Eva Zažímalová
- Institute of Experimental Botany, the Academy of Sciences of the Czech Republic, Rozvojová 263, 165 02 Prague 6, Czech Republic
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20
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Muday GK, Rahman A, Binder BM. Auxin and ethylene: collaborators or competitors? TRENDS IN PLANT SCIENCE 2012; 17:181-95. [PMID: 22406007 DOI: 10.1016/j.tplants.2012.02.001] [Citation(s) in RCA: 217] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 02/01/2012] [Accepted: 02/03/2012] [Indexed: 05/18/2023]
Abstract
The individual roles of auxin and ethylene in controlling the growth and development of young seedlings have been well studied. In recent years, these two hormones have been shown to act synergistically to control specific growth and developmental processes, such as root elongation and root hair formation, as well as antagonistically in other processes, such as lateral root formation and hypocotyl elongation. This review examines the growth and developmental processes that are regulated by crosstalk between these two hormones and explores the mechanistic basis for the regulation of these processes. The emerging trend from these experiments is that ethylene modulates auxin synthesis, transport, and signaling with unique targets and responses in a range of tissues to fine-tune seedling growth and development.
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Affiliation(s)
- Gloria K Muday
- Department of Biology, Wake Forest University, Winston-Salem, NC 27106, USA.
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21
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Osbourn A, Goss RJM, Field RA. The saponins: polar isoprenoids with important and diverse biological activities. Nat Prod Rep 2011; 28:1261-8. [PMID: 21584304 DOI: 10.1039/c1np00015b] [Citation(s) in RCA: 157] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Saponins are polar molecules that consist of a triterpene or steroid aglycone with one or more sugar chains. They are one of the most numerous and diverse groups of plant natural products. These molecules have important ecological and agronomic functions, contributing to pest and pathogen resistance and to food quality in crop plants. They also have a wide range of commercial applications in the food, cosmetics and pharmaceutical sectors. Although primarily found in plants, saponins are produced by certain other organisms, including starfish and sea cucumbers. The under explored biodiversity of this class of natural products is likely to prove to be a vital resource for discovery of high-value compounds. This review will focus on the biological activity of some of the best-studied examples of saponins, on the relationship between structure and function, and on prospects for synthesis of ‘‘designer’’ saponins.
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Affiliation(s)
- Anne Osbourn
- Department of Metabolic Biology, John Innes Centre, Norwich Research Park, UK.
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22
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Laňková M, Smith RS, Pešek B, Kubeš M, Zažímalová E, Petrášek J, Hoyerová K. Auxin influx inhibitors 1-NOA, 2-NOA, and CHPAA interfere with membrane dynamics in tobacco cells. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:3589-98. [PMID: 20595238 PMCID: PMC2921198 DOI: 10.1093/jxb/erq172] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 04/26/2010] [Accepted: 05/25/2010] [Indexed: 05/21/2023]
Abstract
The phytohormone auxin is transported through the plant body either via vascular pathways or from cell to cell by specialized polar transport machinery. This machinery consists of a balanced system of passive diffusion combined with the activities of auxin influx and efflux carriers. Synthetic auxins that differ in the mechanisms of their transport across the plasma membrane together with polar auxin transport inhibitors have been used in many studies on particular auxin carriers and their role in plant development. However, the exact mechanism of action of auxin efflux and influx inhibitors has not been fully elucidated. In this report, the mechanism of action of the auxin influx inhibitors (1-naphthoxyacetic acid (1-NOA), 2-naphthoxyacetic acid (2-NOA), and 3-chloro-4-hydroxyphenylacetic acid (CHPAA)) is examined by direct measurements of auxin accumulation, cellular phenotypic analysis, as well as by localization studies of Arabidopsis thaliana L. auxin carriers heterologously expressed in Nicotiana tabacum L., cv. Bright Yellow cell suspensions. The mode of action of 1-NOA, 2-NOA, and CHPAA has been shown to be linked with the dynamics of the plasma membrane. The most potent inhibitor, 1-NOA, blocked the activities of both auxin influx and efflux carriers, whereas 2-NOA and CHPAA at the same concentration preferentially inhibited auxin influx. The results suggest that these, previously unknown, activities of putative auxin influx inhibitors regulate overall auxin transport across the plasma membrane depending on the dynamics of particular membrane vesicles.
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Affiliation(s)
- Martina Laňková
- Institute of Experimental Botany, the Academy of Sciences of the Czech Republic, Rozvojová 263, CZ-165 02 Prague 6, Czech Republic
| | - Richard S. Smith
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland
| | - Bedřich Pešek
- Institute of Experimental Botany, the Academy of Sciences of the Czech Republic, Rozvojová 263, CZ-165 02 Prague 6, Czech Republic
| | - Martin Kubeš
- Institute of Experimental Botany, the Academy of Sciences of the Czech Republic, Rozvojová 263, CZ-165 02 Prague 6, Czech Republic
| | - Eva Zažímalová
- Institute of Experimental Botany, the Academy of Sciences of the Czech Republic, Rozvojová 263, CZ-165 02 Prague 6, Czech Republic
| | - Jan Petrášek
- Institute of Experimental Botany, the Academy of Sciences of the Czech Republic, Rozvojová 263, CZ-165 02 Prague 6, Czech Republic
| | - Klára Hoyerová
- Institute of Experimental Botany, the Academy of Sciences of the Czech Republic, Rozvojová 263, CZ-165 02 Prague 6, Czech Republic
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Rahman A, Takahashi M, Shibasaki K, Wu S, Inaba T, Tsurumi S, Baskin TI. Gravitropism of Arabidopsis thaliana roots requires the polarization of PIN2 toward the root tip in meristematic cortical cells. THE PLANT CELL 2010; 22:1762-76. [PMID: 20562236 PMCID: PMC2910985 DOI: 10.1105/tpc.110.075317] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 05/14/2010] [Accepted: 05/27/2010] [Indexed: 05/20/2023]
Abstract
In the root, the transport of auxin from the tip to the elongation zone, referred to here as shootward, governs gravitropic bending. Shootward polar auxin transport, and hence gravitropism, depends on the polar deployment of the PIN-FORMED auxin efflux carrier PIN2. In Arabidopsis thaliana, PIN2 has the expected shootward localization in epidermis and lateral root cap; however, this carrier is localized toward the root tip (rootward) in cortical cells of the meristem, a deployment whose function is enigmatic. We use pharmacological and genetic tools to cause a shootward relocation of PIN2 in meristematic cortical cells without detectably altering PIN2 polarization in other cell types or PIN1 polarization. This relocation of cortical PIN2 was negatively regulated by the membrane trafficking factor GNOM and by the regulatory A1 subunit of type 2-A protein phosphatase (PP2AA1) but did not require the PINOID protein kinase. When GNOM was inhibited, PINOID abundance increased and PP2AA1 was partially immobilized, indicating both proteins are subject to GNOM-dependent regulation. Shootward PIN2 specifically in the cortex was accompanied by enhanced shootward polar auxin transport and by diminished gravitropism. These results demonstrate that auxin flow in the root cortex is important for optimal gravitropic response.
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Affiliation(s)
- Abidur Rahman
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan.
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24
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Shibasaki K, Uemura M, Tsurumi S, Rahman A. Auxin response in Arabidopsis under cold stress: underlying molecular mechanisms. THE PLANT CELL 2009; 21:3823-38. [PMID: 20040541 PMCID: PMC2814496 DOI: 10.1105/tpc.109.069906] [Citation(s) in RCA: 188] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 11/28/2009] [Accepted: 12/09/2009] [Indexed: 05/17/2023]
Abstract
To understand the mechanistic basis of cold temperature stress and the role of the auxin response, we characterized root growth and gravity response of Arabidopsis thaliana after cold stress, finding that 8 to 12 h at 4 degrees C inhibited root growth and gravity response by approximately 50%. The auxin-signaling mutants axr1 and tir1, which show a reduced gravity response, responded to cold treatment like the wild type, suggesting that cold stress affects auxin transport rather than auxin signaling. Consistently, expression analyses of an auxin-responsive marker, IAA2-GUS, and a direct transport assay confirmed that cold inhibits root basipetal (shootward) auxin transport. Microscopy of living cells revealed that trafficking of the auxin efflux carrier PIN2, which acts in basipetal auxin transport, was dramatically reduced by cold. The lateral relocalization of PIN3, which has been suggested to mediate the early phase of root gravity response, was also inhibited by cold stress. Additionally, cold differentially affected various protein trafficking pathways. Furthermore, the inhibition of protein trafficking by cold is independent of cellular actin organization and membrane fluidity. Taken together, these results suggest that the effect of cold stress on auxin is linked to the inhibition of intracellular trafficking of auxin efflux carriers.
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Affiliation(s)
- Kyohei Shibasaki
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Iwate, 020-8550, Japan
| | - Matsuo Uemura
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Iwate, 020-8550, Japan
| | - Seiji Tsurumi
- Center for Supports to Research and Education Activities Isotope Division, Kobe University, Nada, Kobe, 657-8501, Japan
| | - Abidur Rahman
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Iwate, 020-8550, Japan
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Mylona P, Owatworakit A, Papadopoulou K, Jenner H, Qin B, Findlay K, Hill L, Qi X, Bakht S, Melton R, Osbourn A. Sad3 and sad4 are required for saponin biosynthesis and root development in oat. THE PLANT CELL 2008; 20:201-12. [PMID: 18203919 PMCID: PMC2254932 DOI: 10.1105/tpc.107.056531] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 12/20/2007] [Accepted: 01/03/2008] [Indexed: 05/18/2023]
Abstract
Avenacins are antimicrobial triterpene glycosides that are produced by oat (Avena) roots. These compounds confer broad-spectrum resistance to soil pathogens. Avenacin A-1, the major avenacin produced by oats, is strongly UV fluorescent and accumulates in root epidermal cells. We previously defined nine loci required for avenacin synthesis, eight of which are clustered. Mutants affected at seven of these (including Saponin-deficient1 [Sad1], the gene for the first committed enzyme in the pathway) have normal root morphology but reduced root fluorescence. In this study, we focus on mutations at the other two loci, Sad3 (also within the gene cluster) and Sad4 (unlinked), which result in stunted root growth, membrane trafficking defects in the root epidermis, and root hair deficiency. While sad3 and sad4 mutants both accumulate the same intermediate, monodeglucosyl avenacin A-1, the effect on avenacin A-1 glucosylation in sad4 mutants is only partial. sad1/sad1 sad3/sad3 and sad1/sad1 sad4/sad4 double mutants have normal root morphology, implying that the accumulation of incompletely glucosylated avenacin A-1 disrupts membrane trafficking and causes degeneration of the epidermis, with consequential effects on root hair formation. Various lines of evidence indicate that these effects are dosage-dependent. The significance of these data for the evolution and maintenance of the avenacin gene cluster is discussed.
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Rahman A, Bannigan A, Sulaman W, Pechter P, Blancaflor EB, Baskin TI. Auxin, actin and growth of the Arabidopsis thaliana primary root. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2007; 50:514-28. [PMID: 17419848 DOI: 10.1111/j.1365-313x.2007.03068.x] [Citation(s) in RCA: 176] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
To understand how auxin regulates root growth, we quantified cell division and elemental elongation, and examined actin organization in the primary root of Arabidopsis thaliana. In treatments for 48 h that inhibited root elongation rate by 50%, we find that auxins and auxin-transport inhibitors can be divided into two classes based on their effects on cell division, elongation and actin organization. Indole acetic acid (IAA), 1-naphthalene acetic acid (NAA) and tri-iodobenzoic acid (TIBA) inhibit root growth primarily through reducing the length of the growth zone rather than the maximal rate of elemental elongation and they do not reduce cell production rate. These three compounds have little effect on the extent of filamentous actin, as imaged in living cells or by chemical fixation and immuno-cytochemistry, but tend to increase actin bundling. In contrast, 2,4-dichlorophenoxy-acetic acid (2,4-D) and naphthylphthalamic acid (NPA) inhibit root growth primarily by reducing cell production rate. These compounds remove actin and slow down cytoplasmic streaming, but do not lead to mislocalization of the auxin-efflux proteins, PIN1 or PIN2. The effects of 2,4-D and NPA were mimicked by the actin inhibitor, latrunculin B. The effects of these compounds on actin were also elicited by a 2 h treatment at higher concentration but were not seen in two mutants, eir1-1 and aux1-7, with deficient auxin transport. Our results show that IAA regulates the size of the root elongation zone whereas 2,4-D affects cell production and actin-dependent processes; and, further, that elemental elongation and localization of PINs are appreciably independent of actin.
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Affiliation(s)
- Abidur Rahman
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
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27
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Rahman A, Nakasone A, Chhun T, Ooura C, Biswas KK, Uchimiya H, Tsurumi S, Baskin TI, Tanaka A, Oono Y. A small acidic protein 1 (SMAP1) mediates responses of the Arabidopsis root to the synthetic auxin 2,4-dichlorophenoxyacetic acid. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2006; 47:788-801. [PMID: 16923017 DOI: 10.1111/j.1365-313x.2006.02832.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
2,4-dichlorophenoxyacetic acid (2,4-D), a chemical analogue of indole-3-acetic acid (IAA), is widely used as a growth regulator and exogenous source of auxin. Because 2,4-D evokes physiological and molecular responses similar to those evoked by IAA, it is believed that they share a common response pathway. Here, we show that a mutant, antiauxin resistant1 (aar1), identified in a screen for resistance to the anti-auxin p-chlorophenoxy-isobutyric acid (PCIB), is resistant to 2,4-D, yet nevertheless responds like the wild-type to IAA and 1-napthaleneacetic acid in root elongation and lateral root induction assays. That the aar1 mutation alters 2,4-D responsiveness specifically was confirmed by analysis of GUS expression in the DR5:GUS and HS:AXR3NT-GUS backgrounds, as well as by real-time PCR quantification of IAA11 expression. The two characterized aar1 alleles both harbor multi-gene deletions; however, 2,4-D responsiveness was restored by transformation with one of the genes missing in both alleles, and the 2,4-D-resistant phenotype was reproduced by decreasing the expression of the same gene in the wild-type using an RNAi construct. The gene encodes a small, acidic protein (SMAP1) with unknown function and present in plants, animals and invertebrates but not in fungi or prokaryotes. Taken together, these results suggest that SMAP1 is a regulatory component that mediates responses to 2,4-D, and that responses to 2,4-D and IAA are partially distinct.
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Affiliation(s)
- Abidur Rahman
- Research Group for Plant Resource Application, Japan Atomic Energy Research Institute, Takasaki 370-1292, Japan
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28
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Kramer EM, Bennett MJ. Auxin transport: a field in flux. TRENDS IN PLANT SCIENCE 2006; 11:382-6. [PMID: 16839804 DOI: 10.1016/j.tplants.2006.06.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Revised: 05/11/2006] [Accepted: 06/27/2006] [Indexed: 05/10/2023]
Abstract
Polar auxin transport is crucial for plant growth and development. Auxin moves between plant cells through a combination of membrane diffusion and carrier-mediated transport. Several classes of membrane proteins that facilitate auxin uptake and efflux have recently been identified in Arabidopsis. The relative contribution to auxin transport made by the different facilitators and by membrane diffusion is unclear. In this Opinion article, we assess the significance of auxin diffusion versus carrier-mediated transport and then discuss the physiological importance of the transport facilitators within the context of the multiple trans-cellular auxin fluxes recently described in the Arabidopsis root apex.
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Affiliation(s)
- Eric M Kramer
- Biology Department, University of Massachusetts, 611 N. Pleasant St., Amherst, MA 01003, USA
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29
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Philosoph-Hadas S, Friedman H, Meir S. Gravitropic bending and plant hormones. VITAMINS AND HORMONES 2005; 72:31-78. [PMID: 16492468 DOI: 10.1016/s0083-6729(05)72002-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Gravitropism is a complex multistep process that redirects the growth of roots and various above-ground organs in response to changes in the direction of the gravity vector. The anatomy and morphology of these graviresponding organs indicates a certain spatial separation between the sensing region and the responding one, a situation that strongly suggests the requirement of phytohormones as mediators to coordinate the process. The Cholodny-Went hypothesis suggested auxin as the main mediator of gravitropism. So far, ample evidence has been gathered with regard to auxin asymmetrical detection, polar and lateral transport involving influx and efflux carriers, response signaling pathway, and possible modes of action in differential cell elongation, supports its major role in gravitropism at least in roots. However, it is becoming clear that the participation of other hormones, acting in concert with auxin, is necessary as well. Of particular importance is the role of ethylene in shoot gravitropism, possibly associated with the modulation of auxin transport or sensitivity, and the key role implicated for cytokinin as the putative root cap inhibitor that controls early root gravitropism. Therefore, the major advances in the understanding of transport and signaling of auxin, ethylene, and cytokinin may shed light on the possibly tight and complicated interactions between them in gravitropism. Not much convincing evidence has been accumulated regarding the participation of other phytohormones, such as gibberellins, abscisic acid, brassinosteroids, jasmonates, and salicylic acid, in gravitropism. However, the emerging concept of cooperative hormone action opens new possibilities for a better understanding of the complex interactions of all phytohormones and their possible synergistic effects and involvement in the gravitropic bending process.
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Affiliation(s)
- Sonia Philosoph-Hadas
- Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, The Volcani Center, Bet-Dagan 50250, Israel
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30
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Swarup R, Kargul J, Marchant A, Zadik D, Rahman A, Mills R, Yemm A, May S, Williams L, Millner P, Tsurumi S, Moore I, Napier R, Kerr ID, Bennett MJ. Structure-function analysis of the presumptive Arabidopsis auxin permease AUX1. THE PLANT CELL 2004. [PMID: 15486104 DOI: 10.1105/tpc.104.024737.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We have investigated the subcellular localization, the domain topology, and the amino acid residues that are critical for the function of the presumptive Arabidopsis thaliana auxin influx carrier AUX1. Biochemical fractionation experiments and confocal studies using an N-terminal yellow fluorescent protein (YFP) fusion observed that AUX1 colocalized with plasma membrane (PM) markers. Because of its PM localization, we were able to take advantage of the steep pH gradient that exists across the plant cell PM to investigate AUX1 topology using YFP as a pH-sensitive probe. The YFP-coding sequence was inserted in selected AUX1 hydrophilic loops to orient surface domains on either apoplastic or cytoplasmic faces of the PM based on the absence or presence of YFP fluorescence, respectively. We were able to demonstrate in conjunction with helix prediction programs that AUX1 represents a polytopic membrane protein composed of 11 transmembrane spanning domains. In parallel, a large aux1 allelic series containing null, partial-loss-of-function, and conditional mutations was characterized to identify the functionally important domains and amino acid residues within the AUX1 polypeptide. Whereas almost all partial-loss-of-function and null alleles cluster in the core permease region, the sole conditional allele aux1-7 modifies the function of the external C-terminal domain.
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Affiliation(s)
- Ranjan Swarup
- School of Biosciences, Sutton Bonington Campus, University of Nottingham, United Kingdom
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31
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Swarup R, Kargul J, Marchant A, Zadik D, Rahman A, Mills R, Yemm A, May S, Williams L, Millner P, Tsurumi S, Moore I, Napier R, Kerr ID, Bennett MJ. Structure-function analysis of the presumptive Arabidopsis auxin permease AUX1. THE PLANT CELL 2004; 16:3069-83. [PMID: 15486104 PMCID: PMC527199 DOI: 10.1105/tpc.104.024737] [Citation(s) in RCA: 258] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2004] [Accepted: 08/22/2004] [Indexed: 05/19/2023]
Abstract
We have investigated the subcellular localization, the domain topology, and the amino acid residues that are critical for the function of the presumptive Arabidopsis thaliana auxin influx carrier AUX1. Biochemical fractionation experiments and confocal studies using an N-terminal yellow fluorescent protein (YFP) fusion observed that AUX1 colocalized with plasma membrane (PM) markers. Because of its PM localization, we were able to take advantage of the steep pH gradient that exists across the plant cell PM to investigate AUX1 topology using YFP as a pH-sensitive probe. The YFP-coding sequence was inserted in selected AUX1 hydrophilic loops to orient surface domains on either apoplastic or cytoplasmic faces of the PM based on the absence or presence of YFP fluorescence, respectively. We were able to demonstrate in conjunction with helix prediction programs that AUX1 represents a polytopic membrane protein composed of 11 transmembrane spanning domains. In parallel, a large aux1 allelic series containing null, partial-loss-of-function, and conditional mutations was characterized to identify the functionally important domains and amino acid residues within the AUX1 polypeptide. Whereas almost all partial-loss-of-function and null alleles cluster in the core permease region, the sole conditional allele aux1-7 modifies the function of the external C-terminal domain.
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Affiliation(s)
- Ranjan Swarup
- School of Biosciences, Sutton Bonington Campus, University of Nottingham, United Kingdom
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32
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Oono Y, Ooura C, Rahman A, Aspuria ET, Hayashi KI, Tanaka A, Uchimiya H. p-Chlorophenoxyisobutyric acid impairs auxin response in Arabidopsis root. PLANT PHYSIOLOGY 2003; 133:1135-47. [PMID: 14526108 PMCID: PMC281609 DOI: 10.1104/pp.103.027847] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2003] [Revised: 06/26/2003] [Accepted: 07/29/2003] [Indexed: 05/18/2023]
Abstract
p-Chlorophenoxyisobutyric acid (PCIB) is known as a putative antiauxin and is widely used to inhibit auxin action, although the mechanism of PCIB-mediated inhibition of auxin action is not characterized very well at the molecular level. In the present work, we showed that PCIB inhibited BA::beta-glucuronidase (GUS) expression induced by indole-3-acetic acid (IAA), 2,4-dichlorophenoxyacetic acid, and 1-naphthaleneacetic acid. PCIB also inhibited auxin-dependent DR5::GUS expression. RNA hybridization and quantitative reverse transcriptase-polymerase chain reaction analyses suggested that PCIB reduced auxin-induced accumulation of transcripts of Aux/IAA genes. In addition, PCIB relieved the reduction of GUS activity in HS::AXR3NT-GUS transgenic line in which auxin inhibits GUS activity by promoting degradation of the AXR3NT-GUS fusion protein. Physiological analysis revealed that PCIB inhibited lateral root production, gravitropic response of roots, and growth of primary roots. These results suggest that PCIB impairs auxin-signaling pathway by regulating Aux/IAA protein stability and thereby affects the auxin-regulated Arabidopsis root physiology.
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Affiliation(s)
- Yutaka Oono
- Department of Ion-beam-applied Biology, Japan Atomic Energy Research Institute, Takasaki 370-1292, Japan.
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33
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Buer CS, Wasteneys GO, Masle J. Ethylene modulates root-wave responses in Arabidopsis. PLANT PHYSIOLOGY 2003; 132:1085-96. [PMID: 12805636 PMCID: PMC167046 DOI: 10.1104/pp.102.019182] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2002] [Revised: 02/21/2003] [Accepted: 03/11/2003] [Indexed: 05/17/2023]
Abstract
When stimulated to bend downward by being held at 45 degrees off vertical but unable to penetrate into agar-based media, Arabidopsis roots develop waving and looping growth patterns. Here, we demonstrate that ethylene modulates these responses. We determined that agar-containing plates sealed with low-porosity film generate abiotic ethylene concentrations of 0.1 to 0.3 microL L(-1), whereas in plates wrapped with porous tape, ethylene remains at trace levels. We demonstrate that exogenous ethylene at concentrations as low as a few nanoliters per liter modulates root waving, root growth direction, and looping but through partly different mechanisms. Nutrients and Suc modify the effects of ethylene on root waving. Thus, ethylene had little effect on temporal wave frequency when nutrients were omitted but reduced it significantly on nutrient-supplemented agar. Suc masked the ethylene response. Ethylene consistently suppressed the normal tendency for roots of Landsberg erecta to skew to the right as they grow against hard-agar surfaces and also generated righthanded petiole twisting. Furthermore, ethylene suppressed root looping, a gravity-dependent growth response that was enhanced by high nutrient and Suc availability. Our work demonstrates that cell file twisting is not essential for root waving or skewing to occur. Differential flank growth accounted for both the extreme root waving on zero-nutrient plates and for root skewing. Root twisting was nutrient-dependent and was thus strongly associated with the looping response. The possible role of auxin transport in these responses and the involvement of circadian rhythms are discussed.
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Affiliation(s)
- Charles S Buer
- Plant Cell Biology, The Institute of Advanced Studies, Research School of Biological Sciences, The Australian National University, G.P.O. Box 475, Canberra, Australian Capital Territory 2601, Australia
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34
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Ahamed A, Rahman A, Hayashi F, Ueji S, Amakawa T, Tsurumi S. Isolation of chromosaponin I-specific antibody by affinity chromatography. Biochem Biophys Res Commun 2003; 302:587-92. [PMID: 12615075 DOI: 10.1016/s0006-291x(03)00217-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Chromosaponin I (CSI), a gamma-pyronyl-triterpenoid saponin isolated from pea and other leguminous plants, modulates several developmental processes of plant roots and activates the sugar taste receptor cells in blowflies. CSI is a unique saponin for its reducing power and biological activities in both plants and insects. In the present paper, we described the method of preparation for CSI-specific antibody using CSI-affinity and soyasaponin I-affinity columns. The antibody's-specific binding activity to CSI was confirmed by a bioassay using Arabidopsis roots and a ligand-molecule interaction analysis using BIAcore 3000. Because of the lability of CSI, the CSI-affinity column was made only by a moderate reaction condition in which CSI was coupled to EAH Sepharose 4B in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC). The special control of the reaction temperature was essential to complete the coupling reaction; the reaction with EDC at 0 degrees C followed by a gradual increase in temperature.
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Affiliation(s)
- Arifa Ahamed
- Graduate School of Science and Technology, Kobe University, Nada-ku, Kobe 657-8501, Japan
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35
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Iturbe-Ormaetxe I, Haralampidis K, Papadopoulou K, Osbourn AE. Molecular cloning and characterization of triterpene synthases from Medicago truncatula and Lotus japonicus. PLANT MOLECULAR BIOLOGY 2003; 51:731-743. [PMID: 12683345 DOI: 10.1023/a:1022519709298] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Cloning of OSCs required for triterpene synthesis from legume species that are amenable to molecular genetics will provide tools to address the importance of triterpenes and their derivatives during normal plant growth and development and also in interactions with symbionts and pathogens. Here we report the cloning and characterization of a total of three triterpene synthases from the legume species Medicago truncatula and Lotus japonicus. These include a beta-amyrin synthase from M. truncatula (MtAMY1) and a mixed function triterpene synthase from Lotus japonicus (LjAMY2). A partial cDNA predicted to encode a beta-amyrin synthase (LjAMY1) was also isolated from L. japonicus. The expression patterns of MtAMY1, LjAMY1 and LjAMY2 and of additional triterpene synthases previously characterised from M. truncatula and pea differ in different plant tissues and during nodulation, suggesting that these enzymes may have distinct roles in plant physiology and development.
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36
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Willemsen V, Friml J, Grebe M, van den Toorn A, Palme K, Scheres B. Cell polarity and PIN protein positioning in Arabidopsis require STEROL METHYLTRANSFERASE1 function. THE PLANT CELL 2003; 15:612-25. [PMID: 12615936 PMCID: PMC150017 DOI: 10.1105/tpc.008433] [Citation(s) in RCA: 215] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Plants have many polarized cell types, but relatively little is known about the mechanisms that establish polarity. The orc mutant was identified originally by defects in root patterning, and positional cloning revealed that the affected gene encodes STEROL METHYLTRANSFERASE1, which is required for the appropriate synthesis and composition of major membrane sterols. smt1(orc) mutants displayed several conspicuous cell polarity defects. Columella root cap cells revealed perturbed polar positioning of different organelles, and in the smt1(orc) root epidermis, polar initiation of root hairs was more randomized. Polar auxin transport and expression of the auxin reporter DR5-beta-glucuronidase were aberrant in smt1(orc). Patterning defects in smt1(orc) resembled those observed in mutants of the PIN gene family of putative auxin efflux transporters. Consistently, the membrane localization of the PIN1 and PIN3 proteins was disturbed in smt1(orc), whereas polar positioning of the influx carrier AUX1 appeared normal. Our results suggest that balanced sterol composition is a major requirement for cell polarity and auxin efflux in Arabidopsis.
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Affiliation(s)
- Viola Willemsen
- Developmental Genetics, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
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37
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Rahman A, Hosokawa S, Oono Y, Amakawa T, Goto N, Tsurumi S. Auxin and ethylene response interactions during Arabidopsis root hair development dissected by auxin influx modulators. PLANT PHYSIOLOGY 2002; 130:1908-17. [PMID: 12481073 PMCID: PMC166701 DOI: 10.1104/pp.010546] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2002] [Revised: 07/15/2002] [Accepted: 09/02/2002] [Indexed: 05/18/2023]
Abstract
The plant hormones auxin and ethylene have been shown to play important roles during root hair development. However, cross talk between auxin and ethylene makes it difficult to understand the independent role of either hormone. To dissect their respective roles, we examined the effects of two compounds, chromosaponin I (CSI) and 1-naphthoxyacetic acid (1-NOA), on the root hair developmental process in wild-type Arabidopsis, ethylene-insensitive mutant ein2-1, and auxin influx mutants aux1-7, aux1-22, and double mutant aux1-7 ein2. Beta-glucuronidase (GUS) expression analysis in the BA-GUS transgenic line, consisting of auxin-responsive domains of PS-IAA4/5 promoter and GUS reporter, revealed that 1-NOA and CSI act as auxin uptake inhibitors in Arabidopsis roots. The frequency of root hairs in ein2-1 roots was greatly reduced in the presence of CSI or 1-NOA, suggesting that endogenous auxin plays a critical role for the root hair initiation in the absence of an ethylene response. All of these mutants showed a reduction in root hair length, however, the root hair length could be restored with a variable concentration of 1-naphthaleneacetic acid (NAA). NAA (10 nM) restored the root hair length of aux1 mutants to wild-type level, whereas 100 nM NAA was needed for ein2-1 and aux1-7 ein2 mutants. Our results suggest that insensitivity in ethylene response affects the auxin-driven root hair elongation. CSI exhibited a similar effect to 1-NOA, reducing root hair growth and the number of root hair-bearing cells in wild-type and ein2-1 roots, while stimulating these traits in aux1-7and aux1-7ein2 roots, confirming that CSI is a unique modulator of AUX1.
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Affiliation(s)
- Abidur Rahman
- Graduate School of Science and Technology, Kobe University, Kobe, Japan
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38
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DeLong A, Mockaitis K, Christensen S. Protein phosphorylation in the delivery of and response to auxin signals. PLANT MOLECULAR BIOLOGY 2002; 49:285-303. [PMID: 12036255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The importance of reversible protein phosphorylation in regulation of plant growth and development has been amply demonstrated by decades of research. Here we discuss recent studies that suggest roles for protein phosphorylation in regulation of both auxin responses and polar auxin transport. Specific kinases act at auxin-requiring steps in floral and embryonic development, and at the junction(s) between light and auxin signaling pathways in hypocotyl elongation and phototropism responses. New evidence for rapid mitogen-activated protein kinase (MAPK) activation by auxin treatment suggests that MAPK cascade(s) might mediate cellular responses to auxin. Protein phosphorylation also may play a crucial role in regulating the activity or turnover of auxin-responsive transcription factors. Auxin transport is modulated by phosphorylation, and protein phosphatase activity is involved in regulation of auxin transport streams in roots. Although the regulatory circuits have not been fully elucidated, these studies suggest that protein phosphorylating and dephosphorylating enzymes perform key functions in auxin biology. In some cases, these enzymes act at the intersections between auxin signaling and other signaling pathways.
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Affiliation(s)
- Alison DeLong
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA.
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Grebe M, Friml J, Swarup R, Ljung K, Sandberg G, Terlou M, Palme K, Bennett MJ, Scheres B. Cell polarity signaling in Arabidopsis involves a BFA-sensitive auxin influx pathway. Curr Biol 2002; 12:329-34. [PMID: 11864575 DOI: 10.1016/s0960-9822(02)00654-1] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Coordination of cell and tissue polarity commonly involves directional signaling. In the Arabidopsis root epidermis, cell polarity is revealed by basal, root tip-oriented, hair outgrowth from hair-forming cells (trichoblasts). The plant hormone auxin displays polar movements and accumulates at maximum concentration in the root tip. The application of polar auxin transport inhibitors evokes changes in trichoblast polarity only at high concentrations and after long-term application. Thus, it remains open whether components of the auxin transport machinery mediate establishment of trichoblast polarity. Here we report that the presumptive auxin influx carrier AUX1 contributes to apical-basal hair cell polarity. AUX1 function is required for polarity changes induced by exogenous application of the auxin 2,4-D, a preferential influx carrier substrate. Similar to aux1 mutants, the vesicle trafficking inhibitor brefeldin A (BFA) interferes with polar hair initiation, and AUX1 function is required for BFA-mediated polarity changes. Consistently, BFA inhibits membrane trafficking of AUX1, trichoblast hyperpolarization induced by 2,4-D, and alters the distal auxin maximum. Our results identify AUX1 as one component of a novel BFA-sensitive auxin transport pathway polarizing cells toward a hormone maximum.
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Affiliation(s)
- Markus Grebe
- Department of Molecular Cell Biology and, 3584 CH, Utrecht University, The Netherlands
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40
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Boonsirichai K, Guan C, Chen R, Masson PH. Root gravitropism: an experimental tool to investigate basic cellular and molecular processes underlying mechanosensing and signal transmission in plants. ANNUAL REVIEW OF PLANT BIOLOGY 2002; 53:421-47. [PMID: 12221983 DOI: 10.1146/annurev.arplant.53.100301.135158] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The ability of plant organs to use gravity as a guide for growth, named gravitropism, has been recognized for over two centuries. This growth response to the environment contributes significantly to the upward growth of shoots and the downward growth of roots commonly observed throughout the plant kingdom. Root gravitropism has received a great deal of attention because there is a physical separation between the primary site for gravity sensing, located in the root cap, and the site of differential growth response, located in the elongation zones (EZs). Hence, this system allows identification and characterization of different phases of gravitropism, including gravity perception, signal transduction, signal transmission, and curvature response. Recent studies support some aspects of an old model for gravity sensing, which postulates that root-cap columellar amyloplasts constitute the susceptors for gravity perception. Such studies have also allowed the identification of several molecules that appear to function as second messengers in gravity signal transduction and of potential signal transducers. Auxin has been implicated as a probable component of the signal that carries the gravitropic information between the gravity-sensing cap and the gravity-responding EZs. This has allowed the identification and characterization of important molecular processes underlying auxin transport and response in plants. New molecular models can be elaborated to explain how the gravity signal transduction pathway might regulate the polarity of auxin transport in roots. Further studies are required to test these models, as well as to study the molecular mechanisms underlying a poorly characterized phase of gravitropism that is independent of an auxin gradient.
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Affiliation(s)
- K Boonsirichai
- Laboratory of Genetics, University of Wisconsin-Madison, 445 Henry Mall, Madison, Wisconsin 53706, USA
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Rahman A, Amakawa T, Goto N, Tsurumi S. Auxin is a positive regulator for ethylene-mediated response in the growth of Arabidopsis roots. PLANT & CELL PHYSIOLOGY 2001; 42:301-7. [PMID: 11266581 DOI: 10.1093/pcp/pce035] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The requirement of auxin for the ethylene-mediated growth response in the root of Arabidopsis thaliana seedlings was investigated using two ethylene-resistant mutants, aux1-7 and eir1-1, whose roots have been shown to have a defect in the auxin influx and efflux carriers, respectively. A 50% inhibition of growth (I(50)) was achieved with 0.84 microl liter(-1) ethylene in wild-type roots, but 71.3 microl liter( -1) ethylene was required to induce I(50) in eir1-1 roots. In aux1-7 roots, I(50) was not obtained even at 1,000 microl liter(-1) ethylene. By contrast, in the presence of 10 nM 1-naphthaleneacetic acid (NAA), the concentrations of ethylene required to induce I(50) in eir1-1 and aux1-7 roots were greatly reduced nearly to the level required in wild-type roots. Since the action of NAA to restore the ethylene response in aux1-7 roots was not replaced by IAA, an increase in the intracellular level of auxin is likely to be the cause for the restoration of ethylene response. NAA at 10 nM did not inhibit root growth when applied solely, but it was the optimum concentration to recover the ethylene response in the mutant roots. These results suggest that auxin is a positive regulator for ethylene-induced inhibition in root elongation.
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Affiliation(s)
- A Rahman
- Graduate School of Science and Technology, Kobe University, Nada-ku, Kobe, 657-8501 Japan
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