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Tan C, Li S, Song J, Zheng X, Zheng H, Xu W, Wan C, Zhang T, Bian Q, Men S. 3,4-Dichlorophenylacetic acid acts as an auxin analog and induces beneficial effects in various crops. Commun Biol 2024; 7:161. [PMID: 38332111 PMCID: PMC10853179 DOI: 10.1038/s42003-024-05848-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 01/23/2024] [Indexed: 02/10/2024] Open
Abstract
Auxins and their analogs are widely used to promote root growth, flower and fruit development, and yield in crops. The action characteristics and application scope of various auxins are different. To overcome the limitations of existing auxins, expand the scope of applications, and reduce side effects, it is necessary to screen new auxin analogs. Here, we identified 3,4-dichlorophenylacetic acid (Dcaa) as having auxin-like activity and acting through the auxin signaling pathway in plants. At the physiological level, Dcaa promotes the elongation of oat coleoptile segments, the generation of adventitious roots, and the growth of crop roots. At the molecular level, Dcaa induces the expression of auxin-responsive genes and acts through auxin receptors. Molecular docking results showed that Dcaa can bind to auxin receptors, among which TIR1 has the highest binding activity. Application of Dcaa at the root tip of the DR5:GUS auxin-responsive reporter induces GUS expression in the root hair zone, which requires the PIN2 auxin efflux carrier. Dcaa also inhibits the endocytosis of PIN proteins like other auxins. These results provide a basis for the application of Dcaa in agricultural practices.
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Affiliation(s)
- Chao Tan
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, 300071, Tianjin, China
| | - Suxin Li
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, 300071, Tianjin, China
| | - Jia Song
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, 300071, Tianjin, China
| | - Xianfu Zheng
- Zhengzhou ZhengShi Chemical Co., Ltd, 450000, Zhengzhou, China
| | - Hao Zheng
- Zhengzhou ZhengShi Chemical Co., Ltd, 450000, Zhengzhou, China
| | - Weichang Xu
- Zhengzhou ZhengShi Chemical Co., Ltd, 450000, Zhengzhou, China
| | - Cui Wan
- Zhengzhou ZhengShi Chemical Co., Ltd, 450000, Zhengzhou, China
| | - Tan Zhang
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, 300071, Tianjin, China
| | - Qiang Bian
- National Pesticide Engineering Research Center (Tianjin), College of Chemistry, Nankai University, 300071, Tianjin, China.
| | - Shuzhen Men
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, 300071, Tianjin, China.
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2
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Perez VC, Zhao H, Lin M, Kim J. Occurrence, Function, and Biosynthesis of the Natural Auxin Phenylacetic Acid (PAA) in Plants. PLANTS (BASEL, SWITZERLAND) 2023; 12:266. [PMID: 36678978 PMCID: PMC9867223 DOI: 10.3390/plants12020266] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 12/14/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
Auxins are a class of plant hormones playing crucial roles in a plant's growth, development, and stress responses. Phenylacetic acid (PAA) is a phenylalanine-derived natural auxin found widely in plants. Although the auxin activity of PAA in plants was identified several decades ago, PAA homeostasis and its function remain poorly understood, whereas indole-3-acetic acid (IAA), the most potent auxin, has been used for most auxin studies. Recent studies have revealed unique features of PAA distinctive from IAA, and the enzymes and intermediates of the PAA biosynthesis pathway have been identified. Here, we summarize the occurrence and function of PAA in plants and highlight the recent progress made in PAA homeostasis, emphasizing PAA biosynthesis and crosstalk between IAA and PAA homeostasis.
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Affiliation(s)
- Veronica C. Perez
- Plant Molecular and Cellular Biology, University of Florida, Gainesville, FL 32611, USA
| | - Haohao Zhao
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA
| | - Makou Lin
- Plant Molecular and Cellular Biology, University of Florida, Gainesville, FL 32611, USA
| | - Jeongim Kim
- Plant Molecular and Cellular Biology, University of Florida, Gainesville, FL 32611, USA
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA
- Genetic Institute, University of Florida, Gainesville, FL 32611, USA
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3
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Perez VC, Dai R, Bai B, Tomiczek B, Askey BC, Zhang Y, Rubin GM, Ding Y, Grenning A, Block AK, Kim J. Aldoximes are precursors of auxins in Arabidopsis and maize. THE NEW PHYTOLOGIST 2021; 231:1449-1461. [PMID: 33959967 PMCID: PMC8282758 DOI: 10.1111/nph.17447] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 04/28/2021] [Indexed: 05/03/2023]
Abstract
Two natural auxins, phenylacetic acid (PAA) and indole-3-acetic acid (IAA), play crucial roles in plant growth and development. One route of IAA biosynthesis uses the glucosinolate intermediate indole-3-acetaldoxime (IAOx) as a precursor, which is thought to occur only in glucosinolate-producing plants in Brassicales. A recent study showed that overproducing phenylacetaldoxime (PAOx) in Arabidopsis increases PAA production. However, it remains unknown whether this increased PAA resulted from hydrolysis of PAOx-derived benzyl glucosinolate or, like IAOx-derived IAA, is directly converted from PAOx. If glucosinolate hydrolysis is not required, aldoxime-derived auxin biosynthesis may occur beyond Brassicales. To better understand aldoxime-derived auxin biosynthesis, we conducted an isotope-labelled aldoxime feeding assay using an Arabidopsis glucosinolate-deficient mutant sur1 and maize, and transcriptomics analysis. Our study demonstrated that the conversion of PAOx to PAA does not require glucosinolates in Arabidopsis. Furthermore, maize produces PAA and IAA from PAOx and IAOx, respectively, indicating that aldoxime-derived auxin biosynthesis also occurs in maize. Considering that aldoxime production occurs widely in the plant kingdom, aldoxime-derived auxin biosynthesis is likely to be more widespread than originally believed. A genome-wide transcriptomics study using PAOx-overproduction plants identified complex metabolic networks among IAA, PAA, phenylpropanoid and tryptophan metabolism.
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Affiliation(s)
- Veronica C. Perez
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611
| | - Ru Dai
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611
| | - Bing Bai
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611
| | - Breanna Tomiczek
- Department of Chemistry, University of Florida, Gainesville, FL, 32611
| | - Bryce C. Askey
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611
| | - Yi Zhang
- Department of Medicinal Chemistry, University of Florida, Gainesville, FL, 32610
| | - Garret M. Rubin
- Department of Medicinal Chemistry, University of Florida, Gainesville, FL, 32610
| | - Yousong Ding
- Department of Medicinal Chemistry, University of Florida, Gainesville, FL, 32610
| | | | - Anna K. Block
- Center for Medical, Agricultural and Veterinary Entomology, U.S. Department of Agriculture-Agricultural Research Service, Gainesville, FL, 32608
| | - Jeongim Kim
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611
- Plant Molecular and Cellular Biology Graduate Program, University of Florida, Gainesville, FL, USA
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4
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Aoi Y, Tanaka K, Cook SD, Hayashi KI, Kasahara H. GH3 Auxin-Amido Synthetases Alter the Ratio of Indole-3-Acetic Acid and Phenylacetic Acid in Arabidopsis. PLANT & CELL PHYSIOLOGY 2020; 61:596-605. [PMID: 31808940 PMCID: PMC7065595 DOI: 10.1093/pcp/pcz223] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 12/02/2019] [Indexed: 05/10/2023]
Abstract
Auxin is the first discovered plant hormone and is essential for many aspects of plant growth and development. Indole-3-acetic acid (IAA) is the main auxin and plays pivotal roles in intercellular communication through polar auxin transport. Phenylacetic acid (PAA) is another natural auxin that does not show polar movement. Although a wide range of species have been shown to produce PAA, its biosynthesis, inactivation and physiological significance in plants are largely unknown. In this study, we demonstrate that overexpression of the CYP79A2 gene, which is involved in benzylglucosinolate synthesis, remarkably increased the levels of PAA and enhanced lateral root formation in Arabidopsis. This coincided with a significant reduction in the levels of IAA. The results from auxin metabolite quantification suggest that the PAA-dependent induction of GRETCHEN HAGEN 3 (GH3) genes, which encode auxin-amido synthetases, promote the inactivation of IAA. Similarly, an increase in IAA synthesis, via the indole-3-acetaldoxime pathway, significantly reduced the levels of PAA. The same adjustment of IAA and PAA levels was also observed by applying each auxin to wild-type plants. These results show that GH3 auxin-amido synthetases can alter the ratio of IAA and PAA in plant growth and development.
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Affiliation(s)
- Yuki Aoi
- Department of Bioregulation and Biointeraction, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, 183-8509 Japan
| | - Keita Tanaka
- Laboratory of Biochemistry, Wageningen University & Research, Wageningen 6708 WE, the Netherlands
| | - Sam David Cook
- Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, 183-8509 Japan
- JSPS International Research Fellow, The Japan Society for the Promotion of Science (JSPS), Chiyoda-ku, Japan
| | - Ken-Ichiro Hayashi
- Department of Biochemistry, Okayama University of Science, Okayama, 700-0005 Japan
| | - Hiroyuki Kasahara
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, 183-8509 Japan
- RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, 230-0045 Japan
- Corresponding author: E-mail, ; Fax, +81-42-360-8830
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5
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Cook SD. An Historical Review of Phenylacetic Acid. PLANT & CELL PHYSIOLOGY 2019; 60:243-254. [PMID: 30649529 DOI: 10.1093/pcp/pcz004] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 12/29/2019] [Indexed: 05/18/2023]
Abstract
Plant hormone biology is an ever-evolving field and as such, novel avenues of research must always be sought. Technological and theoretical advancement can also allow for previously dismissed research to yield equally interesting insights into processes now that they are better understood. The auxin phenylacetic acid (PAA) is an excellent example of this. PAA is a plant auxin that also possesses substantial antimicrobial activity. It has a broad distribution and has been studied in bacteria, fungi, algae and land plants. Research on this compound in plants was prominent in the 1980s, where its bioactivity and broad distribution were frequently examined. Unfortunately, due to the strong interest in the quintessential auxin, indole-3-acetic acid (IAA), research on PAA quickly petered out. Recently, several groups have resumed investigations on this hormone in plants, yet, little is known about PAA biology and its physiological role is unclear. PAA biosynthesis from the amino acid Phe invites direct comparisons with previously studied IAA biosynthesis pathways, and recent work has shown that PAA metabolism and signaling appears to be similar to that of IAA. However, given the large gap between previous work and recent investigations, a historical review of this auxin is required to renew our understanding of PAA. Here, previous work on PAA is reassessed in light of recent research in plants and serves as a synthesis of current knowledge on PAA biology.
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Affiliation(s)
- Sam D Cook
- Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
- JSPS International Research Fellow
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6
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Mashiguchi K, Hisano H, Takeda-Kamiya N, Takebayashi Y, Ariizumi T, Gao Y, Ezura H, Sato K, Zhao Y, Hayashi KI, Kasahara H. Agrobacterium tumefaciens Enhances Biosynthesis of Two Distinct Auxins in the Formation of Crown Galls. PLANT & CELL PHYSIOLOGY 2019; 60:29-37. [PMID: 30169882 PMCID: PMC6343636 DOI: 10.1093/pcp/pcy182] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Accepted: 08/28/2018] [Indexed: 05/08/2023]
Abstract
The plant pathogen Agrobacterium tumefaciens infects plants and introduces the transferred-DNA (T-DNA) region of the Ti-plasmid into nuclear DNA of host plants to induce the formation of tumors (crown galls). The T-DNA region carries iaaM and iaaH genes for synthesis of the plant hormone auxin, indole-3-acetic acid (IAA). It has been demonstrated that the iaaM gene encodes a tryptophan 2-monooxygenase which catalyzes the conversion of tryptophan to indole-3-acetamide (IAM), and the iaaH gene encodes an amidase for subsequent conversion of IAM to IAA. In this article, we demonstrate that A. tumefaciens enhances the production of both IAA and phenylacetic acid (PAA), another auxin which does not show polar transport characteristics, in the formation of crown galls. Using liquid chromatography-tandem mass spectroscopy, we found that the endogenous levels of phenylacetamide (PAM) and PAA metabolites, as well as IAM and IAA metabolites, are remarkably increased in crown galls formed on the stem of tomato plants, implying that two distinct auxins are simultaneously synthesized via the IaaM-IaaH pathway. Moreover, we found that the induction of the iaaM gene dramatically elevated the levels of PAM, PAA and its metabolites, along with IAM, IAA and its metabolites, in Arabidopsis and barley. From these results, we conclude that A. tumefaciens enhances biosynthesis of two distinct auxins in the formation of crown galls.
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Affiliation(s)
- Kiyoshi Mashiguchi
- Graduate School of Life Sciences, Tohoku University, Katahira, Aoba-ku, Sendai, Japan
| | - Hiroshi Hisano
- Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki, Okayama, Japan
| | | | - Yumiko Takebayashi
- RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan
| | - Tohru Ariizumi
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yangbin Gao
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA
| | - Hiroshi Ezura
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Kazuhiro Sato
- Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki, Okayama, Japan
| | - Yunde Zhao
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA
| | - Ken-ichiro Hayashi
- Department of Biochemistry, Okayama University of Science, Okayama, Japan
| | - Hiroyuki Kasahara
- RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, Japan
- Corresponding author: E-mail, ; Fax, +81-42-360-8830. Research area: Growth and development
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7
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Demina IV, Maity PJ, Nagchowdhury A, Ng JLP, van der Graaff E, Demchenko KN, Roitsch T, Mathesius U, Pawlowski K. Accumulation of and Response to Auxins in Roots and Nodules of the Actinorhizal Plant Datisca glomerata Compared to the Model Legume Medicago truncatula. FRONTIERS IN PLANT SCIENCE 2019; 10:1085. [PMID: 31608077 PMCID: PMC6773980 DOI: 10.3389/fpls.2019.01085] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 08/09/2019] [Indexed: 05/13/2023]
Abstract
Actinorhizal nodules are structurally different from legume nodules and show a greater similarity to lateral roots. Because of the important role of auxins in lateral root and nodule formation, auxin profiles were examined in roots and nodules of the actinorhizal species Datisca glomerata and the model legume Medicago truncatula. The auxin response in roots and nodules of both species was analyzed in transgenic root systems expressing a beta-glucuronidase gene under control of the synthetic auxin-responsive promoter DR5. The effects of two different auxin on root development were compared for both species. The auxin present in nodules at the highest levels was phenylacetic acid (PAA). No differences were found between the concentrations of active auxins of roots vs. nodules, while levels of the auxin conjugate indole-3-acetic acid-alanine were increased in nodules compared to roots of both species. Because auxins typically act in concert with cytokinins, cytokinins were also quantified. Concentrations of cis-zeatin and some glycosylated cytokinins were dramatically increased in nodules compared to roots of D. glomerata, but not of M. truncatula. The ratio of active auxins to cytokinins remained similar in nodules compared to roots in both species. The auxin response, as shown by the activation of the DR5 promoter, seemed significantly reduced in nodules compared to roots of both species, suggesting the accumulation of auxins in cell types that do not express the signal transduction pathway leading to DR5 activation. Effects on root development were analyzed for the synthetic auxin naphthaleneacetic acid (NAA) and PAA, the dominant auxin in nodules. Both auxins had similar effects, except that the sensitivity of roots to PAA was lower than to NAA. However, while the effects of both auxins on primary root growth were similar for both species, effects on root branching were different: both auxins had the classical positive effect on root branching in M. truncatula, but a negative effect in D. glomerata. Such a negative effect of exogenous auxin on root branching has previously been found for a cucurbit that forms lateral root primordia in the meristem of the parental root; however, root branching in D. glomerata does not follow that pattern.
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Affiliation(s)
- Irina V. Demina
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Pooja Jha Maity
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Anurupa Nagchowdhury
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Jason L. P. Ng
- Division of Plant Science, Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Eric van der Graaff
- Department of Plant Physiology, Karl-Franzens-Universität Graz, Graz, Austria
| | - Kirill N. Demchenko
- Laboratory of Cellular and Molecular Mechanisms of Plant Development, Komarov Botanical Institute, Russian Academy of Sciences, Saint-Petersburg, Russia
- Laboratory of Molecular and Cellular Biology, All-Russia Research Institute for Agricultural Microbiology, Saint-Petersburg, Russia
| | - Thomas Roitsch
- Department of Plant Physiology, Karl-Franzens-Universität Graz, Graz, Austria
| | - Ulrike Mathesius
- Division of Plant Science, Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Katharina Pawlowski
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
- *Correspondence: Katharina Pawlowski,
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8
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Sumayo MS, Son JS, Ghim SY. Exogenous application of phenylacetic acid promotes root hair growth and induces the systemic resistance of tobacco against bacterial soft-rot pathogen Pectobacterium carotovorum subsp. carotovorum. FUNCTIONAL PLANT BIOLOGY : FPB 2018; 45:1119-1127. [PMID: 32290973 DOI: 10.1071/fp17332] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 05/14/2018] [Indexed: 06/11/2023]
Abstract
Phenylacetic acid (PAA) was evaluated for its capability to promote plant growth and induce systemic resistance in tobacco (Nicotianum tabacum L cv. Xanthi) against the bacterial soft rot pathogen Pectobacterium carotovorum subsp. carotovorum (PCC). Exogenous application of PAA influenced root formation, the activities of defence-related enzymes and the expression of defence and growth-related genes. Increased formation of lateral roots can be observed in tobacco treated with higher PAA concentrations. The highest elicitation of induced systemic resistance (ISR) was found in plants treated with 0.5mM PAA, where the phytotoxic effect was minimal. The activities of the defence enzymes phenylalanine ammonia-lyase (PAL), peroxidase (POD) and polyphnenoloxidase (PPO) were modulated upon treatment with different PAA concentrations. Reverse transcription-PCR analyses showed that 0.5mM PAA modulated the expression of the growth-related genes NtEXP2 and NtEXP6, and the defence-related genes Coi1, NPR1, PR-1a and PR-1b. These results showed that different concentrations of PAA can elicit different responses and effects on tobacco growth and resistance. This study presents the important role of PAA not only on plant growth but also for plant immunity against phytopathogens.
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Affiliation(s)
- Marilyn S Sumayo
- School of Life Sciences, BK21 Plus Kyungpook National University Creative BioResearch Group and Research Institute for Dokdo and Ulleung-do Island, Kyungpook National University, 80 Daehakru, Bukgu, Daegu 41566, Korea
| | - Jin-Soo Son
- School of Life Sciences, BK21 Plus Kyungpook National University Creative BioResearch Group and Research Institute for Dokdo and Ulleung-do Island, Kyungpook National University, 80 Daehakru, Bukgu, Daegu 41566, Korea
| | - Sa-Youl Ghim
- School of Life Sciences, BK21 Plus Kyungpook National University Creative BioResearch Group and Research Institute for Dokdo and Ulleung-do Island, Kyungpook National University, 80 Daehakru, Bukgu, Daegu 41566, Korea
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9
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Urbancsok J, Bones AM, Kissen R. Benzyl Cyanide Leads to Auxin-Like Effects Through the Action of Nitrilases in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2018; 9:1240. [PMID: 30197652 PMCID: PMC6117430 DOI: 10.3389/fpls.2018.01240] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 08/06/2018] [Indexed: 05/19/2023]
Abstract
Plants within the Brassicales order generate glucosinolate hydrolysis products that can exert different biological effects on several organisms. Here, we evaluated the physiological effects of one of these compounds, benzyl cyanide (phenylacetonitrile), when exogenously applied on Arabidopsis thaliana. Treatment with benzyl cyanide led to a dose-dependent reduction of primary root length and total biomass. Further morphological changes like elongated hypocotyls, epinastic cotyledons, and increased formation of adventitious roots resembled a severe auxin-overproducer phenotype. The elevated auxin response was confirmed by histochemical staining and gene expression analysis of auxin-responsive genes. Nitriles are converted by specific enzymes, nitrilases (NIT1-3), to their corresponding carboxylic acids. The nitrilase mutants nit1 and nit2 tolerated benzyl cyanide treatments better than the wild type, with nit2 being less resistant than nit1. A NIT2RNAi line suppressing several nitrilases was resistant to all tested benzyl cyanide concentrations. When exposed to phenylacetic acid (PAA) - the corresponding carboxylic acid of benzyl cyanide - wild type and mutant seedlings were, however, equally susceptible and showed a more severe auxin phenotype than upon cyanide treatment. Here, we demonstrate that the auxin-like effects triggered by benzyl cyanide on Arabidopsis are due to its nitrilase-mediated conversion to the natural auxin PAA.
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Affiliation(s)
| | | | - Ralph Kissen
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
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10
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Kunkel BN, Harper CP. The roles of auxin during interactions between bacterial plant pathogens and their hosts. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:245-254. [PMID: 29272462 DOI: 10.1093/jxb/erx447] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Plant pathogens have evolved several strategies to manipulate the biology of their hosts to facilitate colonization, growth to high levels in plant tissue, and production of disease. One of the less well known of these strategies is the synthesis of plant hormones and hormone analogs, and there is growing evidence that modulation of host hormone signaling is important during pathogenesis. Several plant pathogens produce the auxin indole-3-acetic acid (IAA) and/or virulence factors that modulate host auxin signaling. Auxin is well known for being involved in many aspects of plant growth and development, but recent findings have revealed that elevated IAA levels or enhanced auxin signaling can also promote disease development in some plant-pathogen interactions. In addition to stimulating plant cell growth during infection by gall-forming bacteria, auxin and auxin signaling can antagonize plant defense responses. Auxin can also act as a microbial signaling molecule to impact the biology of some pathogens directly. In this review, we summarize recent progress towards elucidating the roles that auxin production, modification of host auxin signaling, and direct effects of auxin on pathogens play during pathogenesis, with emphasis on the impacts of auxin on interactions with bacterial pathogens.
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Affiliation(s)
- Barbara N Kunkel
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
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11
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Ma Q, Grones P, Robert S. Auxin signaling: a big question to be addressed by small molecules. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:313-328. [PMID: 29237069 PMCID: PMC5853230 DOI: 10.1093/jxb/erx375] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 10/16/2017] [Indexed: 05/20/2023]
Abstract
Providing a mechanistic understanding of the crucial roles of the phytohormone auxin has been an important and coherent aspect of plant biology research. Since its discovery more than a century ago, prominent advances have been made in the understanding of auxin action, ranging from metabolism and transport to cellular and transcriptional responses. However, there is a long road ahead before a thorough understanding of its complex effects is achieved, because a lot of key information is still missing. The availability of an increasing number of technically advanced scientific tools has boosted the basic discoveries in auxin biology. A plethora of bioactive small molecules, consisting of the synthetic auxin-like herbicides and the more specific auxin-related compounds, developed as a result of the exploration of chemical space by chemical biology, have made the tool box for auxin research more comprehensive. This review mainly focuses on the compounds targeting the auxin co-receptor complex, demonstrates the various ways to use them, and shows clear examples of important basic knowledge obtained by their usage. Application of these precise chemical tools, together with an increasing amount of structural information for the major components in auxin action, will certainly aid in strengthening our insights into the complexity and diversity of auxin response.
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Affiliation(s)
- Qian Ma
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Sweden
| | - Peter Grones
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Sweden
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12
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Sugawara S, Mashiguchi K, Tanaka K, Hishiyama S, Sakai T, Hanada K, Kinoshita-Tsujimura K, Yu H, Dai X, Takebayashi Y, Takeda-Kamiya N, Kakimoto T, Kawaide H, Natsume M, Estelle M, Zhao Y, Hayashi KI, Kamiya Y, Kasahara H. Distinct Characteristics of Indole-3-Acetic Acid and Phenylacetic Acid, Two Common Auxins in Plants. PLANT & CELL PHYSIOLOGY 2015; 56:1641-54. [PMID: 26076971 PMCID: PMC4523386 DOI: 10.1093/pcp/pcv088] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 06/07/2015] [Indexed: 05/19/2023]
Abstract
The phytohormone auxin plays a central role in many aspects of plant growth and development. IAA is the most studied natural auxin that possesses the property of polar transport in plants. Phenylacetic acid (PAA) has also been recognized as a natural auxin for >40 years, but its role in plant growth and development remains unclear. In this study, we show that IAA and PAA have overlapping regulatory roles but distinct transport characteristics as auxins in plants. PAA is widely distributed in vascular and non-vascular plants. Although the biological activities of PAA are lower than those of IAA, the endogenous levels of PAA are much higher than those of IAA in various plant tissues in Arabidopsis. PAA and IAA can regulate the same set of auxin-responsive genes through the TIR1/AFB pathway in Arabidopsis. IAA actively forms concentration gradients in maize coleoptiles in response to gravitropic stimulation, whereas PAA does not, indicating that PAA is not actively transported in a polar manner. The induction of the YUCCA (YUC) genes increases PAA metabolite levels in Arabidopsis, indicating that YUC flavin-containing monooxygenases may play a role in PAA biosynthesis. Our results provide new insights into the regulation of plant growth and development by different types of auxins.
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Affiliation(s)
- Satoko Sugawara
- RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, 230-0045 Japan
| | - Kiyoshi Mashiguchi
- RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, 230-0045 Japan
| | - Keita Tanaka
- RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, 230-0045 Japan United Graduate School of Agricultural Science, Tokyo University of Agriculture & Technology, Tokyo, 183-8509 Japan
| | - Shojiro Hishiyama
- Forestry and Forest Products Research Institute, Ibaraki, 305-8687 Japan
| | - Tatsuya Sakai
- Graduate School of Science and Technology, Niigata University, Niigata, 950-2181 Japan
| | - Kousuke Hanada
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Fukuoka, 820-8502 Japan
| | - Kaori Kinoshita-Tsujimura
- Department of Biological Sciences, Graduate School of Science, Osaka University, Osaka, 560-0043 Japan
| | - Hong Yu
- Section of Cell and Developmental Biology and Howard Hughes Medical Institute, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Xinhua Dai
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Yumiko Takebayashi
- RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, 230-0045 Japan
| | - Noriko Takeda-Kamiya
- RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, 230-0045 Japan
| | - Tatsuo Kakimoto
- Department of Biological Sciences, Graduate School of Science, Osaka University, Osaka, 560-0043 Japan
| | - Hiroshi Kawaide
- United Graduate School of Agricultural Science, Tokyo University of Agriculture & Technology, Tokyo, 183-8509 Japan
| | - Masahiro Natsume
- United Graduate School of Agricultural Science, Tokyo University of Agriculture & Technology, Tokyo, 183-8509 Japan
| | - Mark Estelle
- Section of Cell and Developmental Biology and Howard Hughes Medical Institute, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Yunde Zhao
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Ken-Ichiro Hayashi
- Department of Biochemistry, Okayama University of Science, Okayama, 700-0005 Japan
| | - Yuji Kamiya
- RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, 230-0045 Japan
| | - Hiroyuki Kasahara
- RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, 230-0045 Japan Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Saitama, 332-0012 Japan
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Żur I, Dubas E, Krzewska M, Janowiak F. Current insights into hormonal regulation of microspore embryogenesis. FRONTIERS IN PLANT SCIENCE 2015; 6:424. [PMID: 26113852 PMCID: PMC4462098 DOI: 10.3389/fpls.2015.00424] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 05/26/2015] [Indexed: 05/24/2023]
Abstract
Plant growth regulator (PGR) crosstalk and interaction with the plant's genotype and environmental factors play a crucial role in microspore embryogenesis (ME), controlling microspore-derived embryo differentiation and development as well as haploid/doubled haploid plant regeneration. The complexity of the PGR network which could exist at the level of biosynthesis, distribution, gene expression or signaling pathways, renders the creation of an integrated model of ME-control crosstalk impossible at present. However, the analysis of the published data together with the results received recently with the use of modern analytical techniques brings new insights into hormonal regulation of this process. This review presents a short historical overview of the most important milestones in the recognition of hormonal requirements for effective ME in the most important crop plant species and complements it with new concepts that evolved over the last decade of ME studies.
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Affiliation(s)
- Iwona Żur
- The Franciszek Górski Institute of Plant Physiology, Polish Academy of SciencesKraków, Poland
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Abstract
Auxin is a plant hormone involved in an extraordinarily broad variety of biological mechanisms. These range from basic cellular processes, such as endocytosis, cell polarity, and cell cycle control over localized responses such as cell elongation and differential growth, to macroscopic phenomena such as embryogenesis, tissue patterning, and de novo formation of organs. Even though the history of auxin research reaches back more than a hundred years, we are still far from a comprehensive understanding of how auxin governs such a wide range of responses. Some answers to this question may lie in the auxin molecule itself. Naturally occurring auxin-like substances have been found and they may play roles in specific developmental and cellular processes. The molecular mode of auxin action can be further explored by the utilization of synthetic auxin-like molecules. A second area is the perception of auxin, where we know of three seemingly independent receptors and signalling systems, some better understood than others, but each of them probably involved in distinct physiological processes. Lastly, auxin is actively modified, metabolized, and intracellularly compartmentalized, which can have a great impact on its availability and activity. In this review, we will give an overview of these rather recent and emerging areas of auxin research and try to formulate some of the open questions. Without doubt, the manifold facets of auxin biology will not cease to amaze us for a long time to come.
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Affiliation(s)
- Michael Sauer
- Centro Nacional de Biotecnología-CNB-CSIC, Darwin 3, 28049 Madrid, Spain
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Korasick DA, Enders TA, Strader LC. Auxin biosynthesis and storage forms. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:2541-55. [PMID: 23580748 PMCID: PMC3695655 DOI: 10.1093/jxb/ert080] [Citation(s) in RCA: 292] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The plant hormone auxin drives plant growth and morphogenesis. The levels and distribution of the active auxin indole-3-acetic acid (IAA) are tightly controlled through synthesis, inactivation, and transport. Many auxin precursors and modified auxin forms, used to regulate auxin homeostasis, have been identified; however, very little is known about the integration of multiple auxin biosynthesis and inactivation pathways. This review discusses the many ways auxin levels are regulated through biosynthesis, storage forms, and inactivation, and the potential roles modified auxins play in regulating the bioactive pool of auxin to affect plant growth and development.
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Affiliation(s)
- David A. Korasick
- Department of Biology, Washington University in St. Louis, St Louis, MO 63130, USA
| | - Tara A. Enders
- Department of Biology, Washington University in St. Louis, St Louis, MO 63130, USA
| | - Lucia C. Strader
- Department of Biology, Washington University in St. Louis, St Louis, MO 63130, USA
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Patten CL, Blakney AJC, Coulson TJD. Activity, distribution and function of indole-3-acetic acid biosynthetic pathways in bacteria. Crit Rev Microbiol 2012; 39:395-415. [PMID: 22978761 DOI: 10.3109/1040841x.2012.716819] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The capacity to produce the phytohormone indole-3-acetic acid (IAA) is widespread among bacteria that inhabit diverse environments such as soils, fresh and marine waters, and plant and animal hosts. Three major pathways for bacterial IAA synthesis have been characterized that remove the amino and carboxyl groups from the α-carbon of tryptophan via the intermediates indolepyruvate, indoleacetamide, or indoleacetonitrile; the oxidized end product IAA is typically secreted. The enzymes in these pathways often catabolize a broad range of substrates including aromatic amino acids and in some cases the branched chain amino acids. Moreover, expression of some of the genes encoding key IAA biosynthetic enzymes is induced by all three aromatic amino acids. The broad distribution and substrate specificity of the enzymes suggests a role for these pathways beyond plant-microbe interactions in which bacterial IAA has been best studied.
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Affiliation(s)
- Cheryl L Patten
- Department of Biology, University of New Brunswick , Fredericton, New Brunswick , Canada
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Simon S, Petrášek J. Why plants need more than one type of auxin. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2011; 180:454-60. [PMID: 21421392 DOI: 10.1016/j.plantsci.2010.12.007] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Revised: 12/13/2010] [Accepted: 12/15/2010] [Indexed: 05/04/2023]
Abstract
The versatile functionality and physiological importance of the phytohormone auxin is a major focus of attention in contemporary plant science. Recent studies have substantially contributed to our understanding of the molecular mechanisms underlying the physiological role of auxin in plant development. The mechanism of auxin action includes both fast responses not involving gene expression, possibly mediated by Auxin Binding Protein 1 (ABP1), and slower responses requiring auxin-regulated gene expression mediated by F-box proteins. These two mechanisms of action have been described to varying degrees for the major endogenous auxin indole-3-acetic acid (IAA) and for the synthetic auxins 2,4-dichlorophenoxyacetic acid (2,4-D) and naphthalene-1-acetic acid (NAA). However, in addition to IAA, plants synthesize three other compounds that are commonly regarded as "endogenous auxins", namely, 4-chloroindole-3-acetic acid (4-Cl-IAA), indole-3-butyric acid (IBA) and phenylacetic acid (PAA). Although a spectrum of auxinic effects has been identified for all these as well as several other endogenous compounds, we remain largely ignorant of many aspects of their mechanisms of action and the extent to which they contribute to auxin-regulated plant development. Here, we briefly summarize the action of IBA, 4-Cl-IAA and PAA, and discuss the extent to which their action overlaps with that of IAA or results from their metabolic conversions to IAA. Other possible pathways for their action are considered. We present a scheme for homeostatic regulation of IAA levels that embraces other endogenous auxins in terms of the described mechanism of auxin action including its receptor and downstream signal transduction events.
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Affiliation(s)
- Sibu Simon
- Institute of Experimental Botany, ASCR, Rozvojová 263, 16502 Praha 6, Czech Republic
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18
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Johnson CF, Morris DA. Applicability of the chemiosmotic polar diffusion theory to the transport of indol-3yl-acetic acid in the intact pea (Pisum sativum L.). PLANTA 1989; 178:242-248. [PMID: 24212754 DOI: 10.1007/bf00393200] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/1988] [Accepted: 02/01/1989] [Indexed: 06/02/2023]
Abstract
The transport of exogenous indol-3yl-acetic acid (IAA) from the apical tissues of intact, light-grown pea (Pisum sativum L. cv. Alderman) shoots exhibited properties identical to those associated with polar transport in isolated shoot segments. Transport in the stem of apically applied [1-(14)C]-or [5-(3)H]IAA occurred at velocities (approx. 8-15 mm·h(-1)) characteristic of polar transport. Following pulse-labelling, IAA drained from distal tissues after passage of a pulse and the rate characteristics of a pulse were not affected by chases of unlabelled IAA. However, transport of [1-(14)C]IAA was inhibited through a localised region of the stem pretreated with a high concentration of unlabelled IAA or with the synthetic auxins 1-napthaleneacetic acid and 2,4-dichlorophenoxyacetic acid, and label accumulated in more distal tissues. Transport of [1-(14)C]IAA was also completely prevented through regions of the intact stem treated with N-1-naphthylphthalamic acid (NPA) and 2,3,5-triiodobenzoic acid.Export of IAA from the apical bud into the stem increased with total concentration of IAA applied (labelled+unlabelled) but approached saturation at high concentrations (834 mmol·m(-3)). Transport velocity increased with concentration up to 83 mmol·m(-3) IAA but fell again with further increase in concentration.Stem segments (2 mm) cut from intact plants transporting apically applied [1-(14)C]IAA effluxed 93% of their initial radioactivity into buffer (pH 7.0) in 90 min. The half-time for efflux increased from 32.5 to 103.9 min when 3 mmol·m(-3) NPA was included in the efflux medium. Long (30 mm) stem sections cut from immediately below an apical bud 3.0 h after the apical application of [1-(14)C]IAA effluxed IAA when their basal ends, but not their apical ends, were immersed in buffer (pH 7.0). Addition of 3 mmol·m(-3) NPA to the external medium completely prevented this basal efflux.These results support the view that the slow long-distance transport of IAA from the intact shoot apex occurs by polar cell-to-cell transport and that it is mediated by the components of IAA transmembrane transport predicted by the chemiosmotic polar diffusion theory.
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Affiliation(s)
- C F Johnson
- Department of Biology, The University, Building 44, S09 5NH, Southampton, UK
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Johnson CF, Morris DA. Regulation of auxin transport in pea (Pisum sativum L.) by phenylacetic acid: effects on the components of transmembrane transport of indol-3yl-acetic acid. PLANTA 1987; 172:400-407. [PMID: 24225925 DOI: 10.1007/bf00398670] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/1987] [Accepted: 04/24/1987] [Indexed: 06/02/2023]
Abstract
Phenylacetic acid (PAA), a naturally-occurring acidic plant growth substance, was readily taken up by pea (Pisum sativum L. cv. Alderman) stem segments from buffered external solutions by a pH-dependent, non-mediated diffusion. Net uptake from a 0.2 μM solution at pH 4.5 proceeded at a constant rate for at least 60 min and, up to approx. 100 μM, the rate of uptake was directly proportional to the external concentration of the compound. The net rate of uptake of PAA was not affected by the inclusion of indol-3yl-acetic acid (IAA) in the uptake medium (up to approx. 30 μM) and, unlike the net uptake of IAA, was not stimulated by N-1-naphthylphthalamic acid (NPA) or 2,3,5-triiodobenzoic acid. At an external concentration of 0.2 μM and pH 4.5, the net rate of uptake of PAA was about twice that of IAA. It was concluded that the uptake of PAA did not involve the participation of carriers and that PAA was not a transported substrate for the carriers involved in the uptake and polar transport of IAA. Nevertheless, the inclusion of 3-100 μM unlabelled PAA in the external medium greatly stimulated the uptake by pea stem segments of [1-(14)C]IAA (external concentration 0.2 μM). It was concluded that whilst PAA was not a transported substrate for the NPA-sensitive IAA efflux carrier, it interacted with this carrier to inhibit IAA efflux from cells. Over the concentration range 3-100 μM, PAA progressively reduced the stimulatory effect of NPA on IAA uptake, indicating that PAA also inhibited carrier-mediated uptake of IAA. The consequences of these observations for the regulation of polar auxin transport are discussed.
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Affiliation(s)
- C F Johnson
- Department of Biology, The University, Building 44, S09 5NH, Southampton, UK
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