1
|
Singh AA, Ghosh A, Agrawal M, Agrawal SB. Secondary metabolites responses of plants exposed to ozone: an update. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:88281-88312. [PMID: 37440135 DOI: 10.1007/s11356-023-28634-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 07/02/2023] [Indexed: 07/14/2023]
Abstract
Tropospheric ozone (O3) is a secondary pollutant that causes oxidative stress in plants due to the generation of excess reactive oxygen species (ROS). Phenylpropanoid metabolism is induced as a usual response to stress in plants, and induction of key enzyme activities and accumulation of secondary metabolites occur, upon O3 exposure to provide resistance or tolerance. The phenylpropanoid, isoprenoid, and alkaloid pathways are the major secondary metabolic pathways from which plant defense metabolites emerge. Chronic exposure to O3 significantly accelerates the direction of carbon flows toward secondary metabolic pathways, resulting in a resource shift in favor of the synthesis of secondary products. Furthermore, since different cellular compartments have different levels of ROS sensitivity and metabolite sets, intracellular compartmentation of secondary antioxidative metabolites may play a role in O3-induced ROS detoxification. Plants' responses to resource partitioning often result in a trade-off between growth and defense under O3 stress. These metabolic adjustments help the plants to cope with the stress as well as for achieving new homeostasis. In this review, we discuss secondary metabolic pathways in response to O3 in plant species including crops, trees, and medicinal plants; and how the presence of this stressor affects their role as ROS scavengers and structural defense. Furthermore, we discussed how O3 affects key physiological traits in plants, foliar chemistry, and volatile emission, which affects plant-plant competition (allelopathy), and plant-insect interactions, along with an emphasis on soil dynamics, which affect the composition of soil communities via changing root exudation, litter decomposition, and other related processes.
Collapse
Affiliation(s)
- Aditya Abha Singh
- Department of Botany, University of Lucknow, -226007, Lucknow, India
| | - Annesha Ghosh
- Laboratory of Air Pollution and Global Climate Change, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Madhoolika Agrawal
- Laboratory of Air Pollution and Global Climate Change, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Shashi Bhushan Agrawal
- Laboratory of Air Pollution and Global Climate Change, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
| |
Collapse
|
2
|
Forlani G, Giberti S, Doria E. The Levels of DAHP Synthase, the First Enzyme of the Shikimate Pathway, Are Related to Free Aromatic Amino Acids and Glutamine Content in Nicotiana plumbaginifolia Cell Cultures. PLANTS (BASEL, SWITZERLAND) 2023; 12:2524. [PMID: 37447085 DOI: 10.3390/plants12132524] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/29/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023]
Abstract
Aromatic amino acid homeostasis was investigated in cell suspension cultures of Nicotiana plumbaginifolia and was related to the activity of the first enzyme in aromatic biosynthesis, 3-deoxy-D-arabino-heptulosonate-7-phosphate (DAHP) synthase. An inverse relationship was found between the intracellular content of free phenylalanine, tyrosine and tryptophan and enzyme specific activity levels, suggesting the occurrence of end-product control mechanisms. Two DAHP synthase isogenes are present in wild tobacco that showed a different expression pattern during the culture growth cycle. Intracellular levels of aromatic amino acids were increased or decreased by adding the culture medium with phenylalanine, tyrosine and tryptophan, or with sublethal doses of the shikimate pathway inhibitor glyphosate, respectively. As a consequence, enzyme levels varied in the opposite direction. The concomitant exogenous supply of glutamine further reduced enzyme activity in mid-log cells, suggesting induction by both aromatic amino acid depletion and nitrogen starvation.
Collapse
Affiliation(s)
- Giuseppe Forlani
- Laboratory of Plant Physiology and Biochemistry, Department of Life Science and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
| | - Samuele Giberti
- Laboratory of Plant Physiology and Biochemistry, Department of Life Science and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
| | - Enrico Doria
- Laboratory of Plant Biochemistry, Department of Biology and Biotechnology, University of Pavia, 27100 Pavia, Italy
| |
Collapse
|
3
|
Wieloch T, Sharkey TD, Werner RA, Schleucher J. Intramolecular carbon isotope signals reflect metabolite allocation in plants. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2558-2575. [PMID: 35084456 PMCID: PMC9015809 DOI: 10.1093/jxb/erac028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 01/24/2022] [Indexed: 05/26/2023]
Abstract
Stable isotopes at natural abundance are key tools to study physiological processes occurring outside the temporal scope of manipulation and monitoring experiments. Whole-molecule carbon isotope ratios (13C/12C) enable assessments of plant carbon uptake yet conceal information about carbon allocation. Here, we identify an intramolecular 13C/12C signal at tree-ring glucose C-5 and C-6 and develop experimentally testable theories on its origin. More specifically, we assess the potential of processes within C3 metabolism for signal introduction based (inter alia) on constraints on signal propagation posed by metabolic networks. We propose that the intramolecular signal reports carbon allocation into major metabolic pathways in actively photosynthesizing leaf cells including the anaplerotic, shikimate, and non-mevalonate pathway. We support our theoretical framework by linking it to previously reported whole-molecule 13C/12C increases in cellulose of ozone-treated Betula pendula and a highly significant relationship between the intramolecular signal and tropospheric ozone concentration. Our theory postulates a pronounced preference for leaf cytosolic triose-phosphate isomerase to catalyse the forward reaction in vivo (dihydroxyacetone phosphate to glyceraldehyde 3-phosphate). In conclusion, intramolecular 13C/12C analysis resolves information about carbon uptake and allocation enabling more comprehensive assessments of carbon metabolism than whole-molecule 13C/12C analysis.
Collapse
Affiliation(s)
- Thomas Wieloch
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87 Umeå, Sweden
| | - Thomas David Sharkey
- MSU-DOE Plant Research Laboratory, Plant Resilience Institute, and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Roland Anton Werner
- Department of Environmental Systems Science, ETH Zürich, Universitätstrasse 2, 8092 Zürich, Switzerland
| | - Jürgen Schleucher
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87 Umeå, Sweden
| |
Collapse
|
4
|
Fernández-Escalada M, Zulet-González A, Gil-Monreal M, Royuela M, Zabalza A. Physiological performance of glyphosate and imazamox mixtures on Amaranthus palmeri sensitive and resistant to glyphosate. Sci Rep 2019; 9:18225. [PMID: 31796801 PMCID: PMC6890711 DOI: 10.1038/s41598-019-54642-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 11/18/2019] [Indexed: 11/16/2022] Open
Abstract
The herbicides glyphosate and imazamox inhibit the biosynthetic pathway of aromatic amino acids (AAA) and branched-chain amino acids (BCAA), respectively. Both herbicides share several physiological effects in the processes triggered in plants after herbicide application that kills the plant, and mixtures of both herbicides are being used. The aim of this study was to evaluate the physiological effects in the mixture of glyphosate and imazamox in glyphosate-sensitive (GS) and -resistant (GR) populations of the troublesome weed Amaranthus palmeri. The changes detected in the physiological parameters after herbicide mixtures application were similar and even less to the changes detected after individual treatments. This pattern was detected in shikimate, amino acid and carbohydrate content, and it was independent of the EPSPS copy number, as it was detected in both populations. In the case of the transcriptional pattern of the AAA pathway after glyphosate, interesting and contrary interactions with imazamox treatment were detected for both populations; enhancement of the effect in the GS population and alleviation in the GR population. At the transcriptional level, no cross regulation between AAA and BCAA inhibitors was confirmed. This study suggests that mixtures are equally or less toxic than herbicides alone, and would implicate careful considerations when applying the herbicide mixtures.
Collapse
Affiliation(s)
- Manuel Fernández-Escalada
- Institute for Multidisciplinary Research in Applied Biology (IMAB), Universidad Pública de Navarra, Campus Arrosadia s/n, 31006, Pamplona, Spain
| | - Ainhoa Zulet-González
- Institute for Multidisciplinary Research in Applied Biology (IMAB), Universidad Pública de Navarra, Campus Arrosadia s/n, 31006, Pamplona, Spain
| | - Miriam Gil-Monreal
- Institute for Multidisciplinary Research in Applied Biology (IMAB), Universidad Pública de Navarra, Campus Arrosadia s/n, 31006, Pamplona, Spain
| | - Mercedes Royuela
- Institute for Multidisciplinary Research in Applied Biology (IMAB), Universidad Pública de Navarra, Campus Arrosadia s/n, 31006, Pamplona, Spain
| | - Ana Zabalza
- Institute for Multidisciplinary Research in Applied Biology (IMAB), Universidad Pública de Navarra, Campus Arrosadia s/n, 31006, Pamplona, Spain.
| |
Collapse
|
5
|
Yu Z, Yang Z. Understanding different regulatory mechanisms of proteinaceous and non-proteinaceous amino acid formation in tea (Camellia sinensis) provides new insights into the safe and effective alteration of tea flavor and function. Crit Rev Food Sci Nutr 2019; 60:844-858. [DOI: 10.1080/10408398.2018.1552245] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Zhenming Yu
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Ziyin Yang
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| |
Collapse
|
6
|
Changey F, Bagard M, Souleymane M, Lerch TZ. Cascading effects of elevated ozone on wheat rhizosphere microbial communities depend on temperature and cultivar sensitivity. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 242:113-125. [PMID: 29966835 DOI: 10.1016/j.envpol.2018.06.073] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 06/21/2018] [Accepted: 06/21/2018] [Indexed: 06/08/2023]
Abstract
Tropospheric ozone (O3) concentrations have now reached levels that can potentially affect crop production in several regions of the world. The interacting effects of the elevated O3 and temperature on plants are still unclear and their consequences on the rhizosphere microbial communities never studied yet. Here, we conducted a 3-week fumigation experiment on two cultivars of wheat with different tolerance to O3 (Premio and Soissons) at two temperatures (20 °C and 30 °C). The impacts of O3 were measured on plants physiology, rhizosphere chemical environment and microbial communities. Globally, most of the results showed that elevated O3 effects were more pronounced at 20 °C than 30 °C, especially on the most O3-sensitive cultivar (Soissons). Elevated O3 reduced significantly plant root biomass (up to -37% for Soissons) compared to non-fumigated plants. A decrease in the dissolved organic matter with a relative increase of aromatic compounds concentration was also observed under elevated O3, suggesting quantitative and qualitative impacts on roots exudation. While bacterial abundance was negatively affected by O3 plant stress, fungal abundance was found to be stimulated (up to 12 fold compared to non-fumigated plants for Soissons at 20 °C). These changes were accompanied by modifications of the genetic structures and metabolic profiles, with a relative increase of amino acids catabolism. This fully controlled laboratory experiment showed that the effects of elevated O3 on soil microbial communities i) are plant-mediated and depend on the cultivar sensitivity, ii) decrease in warming condition, iii) increase the fungi to bacteria ratio and iv) alter both the genetic structure and the metabolic activities. This study highlights the importance of considering interactive effects between pollutants and climate changes on plant-microbe relationship to better inform models and improve predictions of future states of agroecosystems.
Collapse
Affiliation(s)
- F Changey
- Institut d'Ecologie et des Sciences de l'Environnement (CNRS-UPMC-IRD-UPEC-Univ.Paris-Diderot), Université Paris-Est Créteil, 60 Avenue du Général de Gaulle, 94010 Créteil Cedex, France
| | - M Bagard
- Institut d'Ecologie et des Sciences de l'Environnement (CNRS-UPMC-IRD-UPEC-Univ.Paris-Diderot), Université Paris-Est Créteil, 60 Avenue du Général de Gaulle, 94010 Créteil Cedex, France
| | - M Souleymane
- Institut d'Ecologie et des Sciences de l'Environnement (CNRS-UPMC-IRD-UPEC-Univ.Paris-Diderot), Université Paris-Est Créteil, 60 Avenue du Général de Gaulle, 94010 Créteil Cedex, France
| | - T Z Lerch
- Institut d'Ecologie et des Sciences de l'Environnement (CNRS-UPMC-IRD-UPEC-Univ.Paris-Diderot), Université Paris-Est Créteil, 60 Avenue du Général de Gaulle, 94010 Créteil Cedex, France.
| |
Collapse
|
7
|
Kanagendran A, Pazouki L, Li S, Liu B, Kännaste A, Niinemets Ü. Ozone-triggered surface uptake and stress volatile emissions in Nicotiana tabacum 'Wisconsin'. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:681-697. [PMID: 29301045 PMCID: PMC5853501 DOI: 10.1093/jxb/erx431] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 11/17/2017] [Indexed: 05/04/2023]
Abstract
Ozone is a strong oxidant and a key stress elicitor. The immediate and longer term impacts of ozone are poorly understood in species with emission of both de novo synthesized and stored volatiles, such a tobacco (Nicotiana tabacum), which has terpene-containing glandular trichomes on the leaf surface. In this study, we exposed N. tabacum 'Wisconsin' leaves to acute ozone doses of 0 (control), 400, 600, 800, and 1000 ppb for 30 min and studied the effects of ozone exposure on ozone uptake, gas-exchange characteristics, and emissions of lipoxygenase pathway volatiles, monoterpenes, and sesquiterpenes. Foliage emissions of lipoxygenase pathway volatiles were quantitatively related to the severity of ozone exposure, but the stress dose vs. emission relationship was weaker for terpenoids. Analysis of leaf terpene content and composition indicated that several monoterpenes and sesquiterpenes were not stored in leaves and were synthesized de novo upon ozone exposure. The highest degree of elicitation for each compound was observed immediately after ozone treatment and it declined considerably during recovery. Leaf ozone uptake was dominated by non-stomatal deposition, and the emissions of total lipoxygenase pathway volatiles and mono- and sesquiterpenes were positively correlated with non-stomatal ozone deposition. Overall, this study demonstrates remarkably high ozone resistance of the studied tobacco cultivar and indicates that ozone's effects on volatile emissions primarily reflect modifications in the release of stored volatiles and reaction of ozone with the leaf surface structure.
Collapse
Affiliation(s)
- Arooran Kanagendran
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Leila Pazouki
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
- Department of Biology, University of Louisville, Louisville, KY, USA
| | - Shuai Li
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Bin Liu
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Astrid Kännaste
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Ülo Niinemets
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
- Estonian Academy of Sciences, Tallinn, Estonia
| |
Collapse
|
8
|
Kanagendran A, Pazouki L, Niinemets Ü. Differential regulation of volatile emission from Eucalyptus globulus leaves upon single and combined ozone and wounding treatments through recovery and relationships with ozone uptake. ENVIRONMENTAL AND EXPERIMENTAL BOTANY 2018; 145:21-38. [PMID: 29970942 PMCID: PMC6020072 DOI: 10.1016/j.envexpbot.2017.10.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Both ozone and wounding constitute two key abiotic stress factors, but their interactive effects on plant constitutive and stress-elicited volatile (VOC) emissions are poorly understood. Furthermore, the information on time-dependent modifications in VOC release during recovery from a combined stress is very limited. We studied the modifications in photosynthetic characteristics and constitutive and stress-induced volatile emissions in response to single and combined applications of acute ozone (4, 5, and 6 ppm) and wounding treatments through recovery (0.5-75 h) in a constitutive isoprene and mono- and sesquiterpene emitter Eucalyptus globulus. Overall, the photosynthetic characteristics were surprisingly resistant to all ozone and wounding treatments. Constitutive isoprene emissions were strongly upregulated by ozone and combined ozone and wounding treatments and remained high through recovery phase, but wounding applied alone reduced isoprene emission. All stress treatments enhanced emissions of lipoxygenase pathway volatiles (LOX), mono- and sesquiterpenes, saturated aldehydes (C7-C10), benzenoids, and geranylgeranyl diphosphate (GGDP) pathway volatiles. Once elicited, GGDP volatile, saturated aldehyde and benzenoid emissions remained high through the recovery period. In contrast, LOX emissions, and total mono- and sesquiterpene emissions decreased through recovery period. However, secondary rises in total sesquiterpene emissions at 75 h and in total monoterpenes at 25-50 h were observed. Overall, acute ozone and wounding treatments synergistically altered gas exchange characteristics and stress volatile emissions. Through the treatments and recovery period, stomatal ozone uptake rate and volatile emission rates were poorly correlated, reflecting possible ozone-scavenging effect of volatiles and thus, reduction of effective ozone dose and elicitation of induced defense by the acute ozone concentrations applied. These results underscore the important role of interactive stresses on both constitutive and induced volatile emission responses.
Collapse
Affiliation(s)
- Arooran Kanagendran
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia
| | - Leila Pazouki
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia
| | - Ülo Niinemets
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia
- Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn, Estonia
| |
Collapse
|
9
|
Fernández-Escalada M, Zulet-González A, Gil-Monreal M, Zabalza A, Ravet K, Gaines T, Royuela M. Effects of EPSPS Copy Number Variation (CNV) and Glyphosate Application on the Aromatic and Branched Chain Amino Acid Synthesis Pathways in Amaranthus palmeri. FRONTIERS IN PLANT SCIENCE 2017; 8:1970. [PMID: 29201035 PMCID: PMC5696356 DOI: 10.3389/fpls.2017.01970] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 11/01/2017] [Indexed: 05/09/2023]
Abstract
A key enzyme of the shikimate pathway, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS; EC 2.5.1.19), is the known target of the widely used herbicide glyphosate. Glyphosate resistance in Amaranthus palmeri, one of the most troublesome weeds in agriculture, has evolved through increased EPSPS gene copy number. The aim of this work was to study the pleiotropic effects of (i) EPSPS increased transcript abundance due to gene copy number variation (CNV) and of (ii) glyphosate application on the aromatic amino acid (AAA) and branched chain amino acid (BCAA) synthesis pathways. Hydroponically grown glyphosate sensitive (GS) and glyphosate resistant (GR) plants were treated with glyphosate 3 days after treatment. In absence of glyphosate treatment, high EPSPS gene copy number had only a subtle effect on transcriptional regulation of AAA and BCAA pathway genes. In contrast, glyphosate treatment provoked a general accumulation of the transcripts corresponding to genes of the AAA pathway leading to synthesis of chorismate in both GS and GR. After chorismate, anthranilate synthase transcript abundance was higher while chorismate mutase transcription showed a small decrease in GR and remained stable in GS, suggesting a regulatory branch point in the pathway that favors synthesis toward tryptophan over phenylalanine and tyrosine after glyphosate treatment. This was confirmed by studying enzyme activities in vitro and amino acid analysis. Importantly, this upregulation was glyphosate dose dependent and was observed similarly in both GS and GR populations. Glyphosate treatment also had a slight effect on the expression of BCAA genes but no general effect on the pathway could be observed. Taken together, our observations suggest that the high CNV of EPSPS in A. palmeri GR populations has no major pleiotropic effect on the expression of AAA biosynthetic genes, even in response to glyphosate treatment. This finding supports the idea that the fitness cost associated with EPSPS CNV in A. palmeri may be limited.
Collapse
Affiliation(s)
| | - Ainhoa Zulet-González
- Departamento Ciencias del Medio Natural, Universidad Pública de Navarra, Pamplona, Spain
| | - Miriam Gil-Monreal
- Departamento Ciencias del Medio Natural, Universidad Pública de Navarra, Pamplona, Spain
| | - Ana Zabalza
- Departamento Ciencias del Medio Natural, Universidad Pública de Navarra, Pamplona, Spain
| | - Karl Ravet
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO, United States
| | - Todd Gaines
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO, United States
| | - Mercedes Royuela
- Departamento Ciencias del Medio Natural, Universidad Pública de Navarra, Pamplona, Spain
| |
Collapse
|
10
|
Sun D, Li S, Niu L, Reid MS, Zhang Y, Jiang CZ. PhOBF1, a petunia ocs element binding factor, plays an important role in antiviral RNA silencing. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:915-930. [PMID: 28053190 PMCID: PMC6055658 DOI: 10.1093/jxb/erw490] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 12/09/2016] [Indexed: 05/09/2023]
Abstract
Virus-induced gene silencing (VIGS) is a common reverse genetics strategy for characterizing the function of genes in plants. The detailed mechanism governing RNA silencing efficiency triggered by viruses is largely unclear. Here, we reveal that a petunia (Petunia hybrida) ocs element binding factor, PhOBF1, one of the basic leucine zipper (bZIP) transcription factors, was up-regulated by Tobacco rattle virus (TRV) infection. Simultaneous silencing of PhOBF1 and a reporter gene, phytoene desaturase (PDS) or chalcone synthase (CHS), by TRV-based VIGS led to a failure of the development of leaf photobleaching or the white-corollas phenotype. PhOBF1 silencing caused down-regulation of RNA silencing-related genes, including RNA-dependent RNA polymerases (RDRs), Dicer-like RNase III enzymes (DCLs), and Argonautes (AGOs). After inoculation with the TRV-PhPDS, PhOBF1-RNAi lines exhibited a substantially impaired PDS silencing efficiency, whereas overexpression of PhOBF1 resulted in a recovery of the silencing phenotype (photobleaching) in systemic leaves. A compromised resistance to TRV and Tobacco mosaic virus was found in PhOBF1-RNAi lines, while PhOBF1-overexpressing lines displayed an enhanced resistance to their infections. Compared with wild-type plants, PhOBF1-silenced plants accumulated lower levels of free salicylic acid (SA), salicylic acid glucoside, and phenylalanine, contrarily to higher levels of those in plants overexpressing PhOBF1. Furthermore, transcripts of a number of genes associated with the shikimate and phenylpropanoid pathways were decreased or increased in PhOBF1-RNAi or PhOBF1-overexpressing lines, respectively. Taken together, the data suggest that PhOBF1 regulates TRV-induced RNA silencing efficiency through modulation of RDRs, DCLs, and AGOs mediated by the SA biosynthesis pathway.
Collapse
Affiliation(s)
- Daoyang Sun
- Department of Landscape Architecture and Arts, Northwest A&F University, Yangling, Shaanxi, China
- Department of Plant Sciences, University of California Davis, Davis, CA, USA
| | - Shaohua Li
- Department of Landscape Architecture and Arts, Northwest A&F University, Yangling, Shaanxi, China
| | - Lixin Niu
- Department of Landscape Architecture and Arts, Northwest A&F University, Yangling, Shaanxi, China
| | - Michael S Reid
- Department of Plant Sciences, University of California Davis, Davis, CA, USA
| | - Yanlong Zhang
- Department of Landscape Architecture and Arts, Northwest A&F University, Yangling, Shaanxi, China
| | - Cai-Zhong Jiang
- Department of Plant Sciences, University of California Davis, Davis, CA, USA
- Crops Pathology and Genetic Research Unit, United States Department of Agriculture, Agricultural Research Service, Davis, CA, USA
| |
Collapse
|
11
|
El-Azaz J, de la Torre F, Ávila C, Cánovas FM. Identification of a small protein domain present in all plant lineages that confers high prephenate dehydratase activity. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 87:215-29. [PMID: 27125254 DOI: 10.1111/tpj.13195] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 04/07/2016] [Accepted: 04/14/2016] [Indexed: 05/20/2023]
Abstract
l-Phenylalanine serves as a building block for the biosynthesis of proteins, but also as a precursor for a wide range of plant-derived compounds essential for plants and animals. Plants can synthesize Phe within the plastids using arogenate as a precursor; however, an alternative pathway using phenylpyruvate as an intermediate, described for most microorganisms, has recently been proposed. The functionality of this pathway requires the existence of enzymes with prephenate dehydratase (PDT) activity (EC 4.2.1.51) in plants. Using phylogenetic studies, functional complementation assays in yeast and biochemical analysis, we have identified the enzymes displaying PDT activity in Pinus pinaster. Through sequence alignment comparisons and site-directed mutagenesis we have identified a 22-amino acid region conferring PDT activity (PAC domain) and a single Ala314 residue critical to trigger this activity. Our results demonstrate that all plant clades include PAC domain-containing ADTs, suggesting that the PDT activity, and thus the ability to synthesize Phe using phenylpyruvate as an intermediate, has been preserved throughout the evolution of plants. Moreover, this pathway together with the arogenate pathway gives plants a broad and versatile capacity to synthesize Phe and its derived compounds. PAC domain-containing enzymes are also present in green and red algae, and glaucophytes, the three emerging clades following the primary endosymbiont event resulting in the acquisition of plastids in eukaryotes. The evolutionary prokaryotic origin of this domain is discussed.
Collapse
Affiliation(s)
- Jorge El-Azaz
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, Málaga, 29071, Spain
| | - Fernando de la Torre
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, Málaga, 29071, Spain
| | - Concepción Ávila
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, Málaga, 29071, Spain
| | - Francisco M Cánovas
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, Málaga, 29071, Spain
| |
Collapse
|
12
|
Pratelli R, Pilot G. Regulation of amino acid metabolic enzymes and transporters in plants. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:5535-56. [PMID: 25114014 DOI: 10.1093/jxb/eru320] [Citation(s) in RCA: 196] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Amino acids play several critical roles in plants, from providing the building blocks of proteins to being essential metabolites interacting with many branches of metabolism. They are also important molecules that shuttle organic nitrogen through the plant. Because of this central role in nitrogen metabolism, amino acid biosynthesis, degradation, and transport are tightly regulated to meet demand in response to nitrogen and carbon availability. While much is known about the feedback regulation of the branched biosynthesis pathways by the amino acids themselves, the regulation mechanisms at the transcriptional, post-transcriptional, and protein levels remain to be identified. This review focuses mainly on the current state of our understanding of the regulation of the enzymes and transporters at the transcript level. Current results describing the effect of transcription factors and protein modifications lead to a fragmental picture that hints at multiple, complex levels of regulation that control and coordinate transport and enzyme activities. It also appears that amino acid metabolism, amino acid transport, and stress signal integration can influence each other in a so-far unpredictable fashion.
Collapse
Affiliation(s)
- Réjane Pratelli
- Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA 24060, USA
| | - Guillaume Pilot
- Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA 24060, USA
| |
Collapse
|
13
|
Sun J, Feng Z, Ort DR. Impacts of rising tropospheric ozone on photosynthesis and metabolite levels on field grown soybean. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 226:147-61. [PMID: 25113460 DOI: 10.1016/j.plantsci.2014.06.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 06/07/2014] [Accepted: 06/13/2014] [Indexed: 06/03/2023]
Abstract
The response of leaf photosynthesis and metabolite profiles to ozone (O3) exposure ranging from 37 to 116 ppb was investigated in two soybean cultivars Dwight and IA3010 in the field under fully open-air conditions. Leaf photosynthesis, total non-structural carbohydrates (TNC) and total free amino acids (TAA) decreased linearly with increasing O3 levels in both cultivars with average decrease of 7% for an increase in O3 levels by 10 ppb. Ozone interacted with developmental stages and leaf ages, and caused higher damage at later reproductive stages and in older leaves. Ozone affected yield mainly via reduction of maximum rate of Rubisco carboxylation (Vcmax) and maximum rates of electron transport (Jmax) as well as a shorter growing season due to earlier onset of canopy senescence. For all parameters investigated the critical O3 levels (∼50 ppb) for detectable damage fell within O3 levels that occur routinely in soybean fields across the US and elsewhere in the world. Strong correlations were observed in O3-induced changes among yield, photosynthesis, TNC, TAA and many metabolites. The broad range of metabolites that showed O3 dose dependent effect is consistent with multiple interaction loci and thus multiple targets for improving the tolerance of soybean to O3.
Collapse
Affiliation(s)
- Jindong Sun
- Institute for Genomic Biology, University of Illinois, Urbana, IL 61801, United States.
| | - Zhaozhong Feng
- Institute for Genomic Biology, University of Illinois, Urbana, IL 61801, United States
| | - Donald R Ort
- Institute for Genomic Biology, University of Illinois, Urbana, IL 61801, United States; Global Change and Photosynthesis Research Unit, USDA/ARS, University of Illinois, Urbana, IL 61801, United States
| |
Collapse
|
14
|
Dumont J, Keski-Saari S, Keinänen M, Cohen D, Ningre N, Kontunen-Soppela S, Baldet P, Gibon Y, Dizengremel P, Vaultier MN, Jolivet Y, Oksanen E, Le Thiec D. Ozone affects ascorbate and glutathione biosynthesis as well as amino acid contents in three Euramerican poplar genotypes. TREE PHYSIOLOGY 2014; 34:253-266. [PMID: 24682617 DOI: 10.1093/treephys/tpu004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Ozone is an air pollutant that causes oxidative stress by generation of reactive oxygen species (ROS) within the leaf. The capacity to detoxify ROS and repair ROS-induced damage may contribute to ozone tolerance. Ascorbate and glutathione are known to be key players in detoxification. Ozone effects on their biosynthesis and on amino acid metabolism were investigated in three Euramerican poplar genotypes (Populus deltoides Bartr. × Populus nigra L.) differing in ozone sensitivity. Total ascorbate and glutathione contents were increased in response to ozone in all genotypes, with the most resistant genotype (Carpaccio) showing an increase of up to 70%. Reduced ascorbate (ASA) concentration at least doubled in the two most resistant genotypes (Carpaccio and Cima), whereas the most sensitive genotype (Robusta) seemed unable to regenerate ASA from oxidized ascorbate (DHA), leading to an increase of 80% of the oxidized form. Increased ascorbate (ASA + DHA) content correlated with the increase in gene expression in its biosynthetic pathway, especially the putative gene of GDP-l-galactose phosphorylase VTC2. Increased cysteine availability combined with increased expression of γ-glutamylcysteine synthetase (GSH1) and glutathione synthetase (GSH2) genes allows higher glutathione biosynthesis in response to ozone, particularly in Carpaccio. In addition, ozone caused a remobilization of amino acids with a decreased pool of total amino acids and an increase of Cys and putrescine, especially in Carpaccio. In addition, the expression of genes encoding threonine aldolase was strongly induced only in the most tolerant genotype, Carpaccio. Reduced ascorbate levels could partly explain the sensitivity to ozone for Robusta but not for Cima. Reduced ascorbate level alone is not sufficient to account for ozone tolerance in poplar, and it is necessary to consider several other factors including glutathione content.
Collapse
|
15
|
Mir R, Jallu S, Singh TP. The shikimate pathway: Review of amino acid sequence, function and three-dimensional structures of the enzymes. Crit Rev Microbiol 2013; 41:172-89. [DOI: 10.3109/1040841x.2013.813901] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
16
|
Ernst D. Integrated Studies on Abiotic Stress Defence in Trees. DEVELOPMENTS IN ENVIRONMENTAL SCIENCE 2013. [DOI: 10.1016/b978-0-08-098349-3.00014-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
17
|
Torras-Claveria L, Jáuregui O, Codina C, Tiburcio AF, Bastida J, Viladomat F. Analysis of phenolic compounds by high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry in senescent and water-stressed tobacco. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2012; 182:71-8. [PMID: 22118617 DOI: 10.1016/j.plantsci.2011.02.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 02/17/2011] [Accepted: 02/22/2011] [Indexed: 05/11/2023]
Abstract
Evaluation of a significant part of the phenylpropanoid pathway metabolites is facilitated by the fast high-performance liquid chromatography with electrospray ionization tandem mass spectrometry (LC-MS/MS) analytical method. The technology described was applied in tobacco plants (Nicotiana tabacum L. cv. Wisconsin) to identify 20 phenolic compounds and to detect differences in phenylpropanoid profiles in two types of experiments. In the first one, senescent and non-senescent parts of flowering plants were compared, while in the second, watered plants were compared with water-stressed young plants. The 20 identified phenolic compounds were: seven hydroxycinnamoylquinic acids, seven hydroxycinnamic acid glucosides, one salicylic acid glucoside, two conjugated flavonols with disaccharides, and three hydroxycinnamic acid amides (HCAA) of putrescine. In general, the levels of phenylpropanoid compounds increased under water stress or senescent conditions, with the exception of HCAA, which decreased in senescent samples, and 4-O-p-coumaroylquinic acid and trihydroxycinamic acid-O-glucoside, which did not change in both experiments. The main product in all the samples was 5-O-caffeoylquinic acid (neochlorogenic acid). Another compound, kaempferol-7-O-neohesperidoside, was tentatively identified for the first time in tobacco plants. This method, which can be applied in other plant species, allows a simple and efficient comparative study of metabolite profile variations (qualitative and quantitative) in response to different physiological and/or environmental plant situations.
Collapse
Affiliation(s)
- Laura Torras-Claveria
- Departament de Productes Naturals, Biologia Vegetal i Edafologia, Facultat de Farmàcia, Universitat de Barcelona, Avinguda Joan XXIII s/n, Avda. Diagonal, 643, 08028 Barcelona, Catalonia, Spain
| | | | | | | | | | | |
Collapse
|
18
|
Maeda H, Dudareva N. The shikimate pathway and aromatic amino Acid biosynthesis in plants. ANNUAL REVIEW OF PLANT BIOLOGY 2012; 63:73-105. [PMID: 22554242 DOI: 10.1146/annurev-arplant-042811-105439] [Citation(s) in RCA: 740] [Impact Index Per Article: 61.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
L-tryptophan, L-phenylalanine, and L-tyrosine are aromatic amino acids (AAAs) that are used for the synthesis of proteins and that in plants also serve as precursors of numerous natural products, such as pigments, alkaloids, hormones, and cell wall components. All three AAAs are derived from the shikimate pathway, to which ≥30% of photosynthetically fixed carbon is directed in vascular plants. Because their biosynthetic pathways have been lost in animal lineages, the AAAs are essential components of the diets of humans, and the enzymes required for their synthesis have been targeted for the development of herbicides. This review highlights recent molecular identification of enzymes of the pathway and summarizes the pathway organization and the transcriptional/posttranscriptional regulation of the AAA biosynthetic network. It also identifies the current limited knowledge of the subcellular compartmentalization and the metabolite transport involved in the plant AAA pathways and discusses metabolic engineering efforts aimed at improving production of the AAA-derived plant natural products.
Collapse
Affiliation(s)
- Hiroshi Maeda
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907-2010, USA.
| | | |
Collapse
|
19
|
Xu M, Yang B, Dong J, Lu D, Jin H, Sun L, Zhu Y, Xu X. Enhancing hypericin production of Hypericum perforatum cell suspension culture by ozone exposure. Biotechnol Prog 2011; 27:1101-6. [DOI: 10.1002/btpr.614] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 02/09/2011] [Indexed: 11/08/2022]
|
20
|
Fares S, Oksanen E, Lännenpää M, Julkunen-Tiitto R, Loreto F. Volatile emissions and phenolic compound concentrations along a vertical profile of Populus nigra leaves exposed to realistic ozone concentrations. PHOTOSYNTHESIS RESEARCH 2010; 104:61-74. [PMID: 20407831 DOI: 10.1007/s11120-010-9549-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 04/01/2010] [Indexed: 05/29/2023]
Abstract
Plants are exposed to increasing levels of tropospheric ozone concentrations. This pollutant penetrates in leaves through stomata and quickly reacts inside leaves, thus making plants valuable ozone sinks, but at the same time triggers oxidation processes which lead to leaf injuries. To counteract these negative effects, plants produce an array of antioxidants which react with ozone and reactive molecules which ozone generates in the leaf tissues. In this study, we measured the effect of an ozone concentration which is likely to be attained in many areas of the world in the near future (80 ppb) on leaves of the vertical profile of the widespread agroforestry species Populus nigra. Changes in (1) physiological parameters (photosynthesis and stomatal conductance), (2) ozone uptake, (3) emission of volatile organic compounds (VOCs, i.e. isoprene, methanol and other oxygenated compounds), (4) concentration of antioxidant surface compounds, and (5) concentration of phenolic compounds were assessed. The aim was to assess whether the defensive pathways leading to isoprenoids and phenolics formation were induced when a moderate and chronic increment of ozone is not able to damage photosynthesis. No visual injuries and minor changes in physiology and ozone uptake were observed. The emission of isoprene and oxygenated six-carbon (C6) volatiles were inhibited by ozone, whereas methanol emission was increased, especially in developing leaves. We interpret these results as suggesting an ontogenetic shift in ozone-treated leaves, leading to a slower development and a faster senescence. Most surface and phenolic compounds showed a declining trend in concentration from the youngest to the fully expanded leaves. Ozone reduced the concentrations of chlorogenic acid derivatives at the leaf surface, whereas in total leaf extracts a metabolic shift towards few phenolics with higher antioxidant capacity was observed.
Collapse
Affiliation(s)
- Silvano Fares
- Consiglio Nazionale delle Ricerche (CNR), Istituto di Biologia Agroambientale e Forestale (IBAF), Rome, Italy.
| | | | | | | | | |
Collapse
|
21
|
Wurst S, van Beersum S, Wagenaar R, Bakx-Schotman T, Drigo B, Janzik I, Lanoue A, van der Putten WH. Plant defence against nematodes is not mediated by changes in the soil microbial community. Funct Ecol 2009. [DOI: 10.1111/j.1365-2435.2009.01543.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
22
|
Iriti M, Di Maro A, Bernasconi S, Burlini N, Simonetti P, Picchi V, Panigada C, Gerosa G, Parente A, Faoro F. Nutritional traits of bean ( Phaseolus vulgaris ) seeds from plants chronically exposed to ozone pollution. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2009; 57:201-208. [PMID: 19055366 DOI: 10.1021/jf802819m] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The effect of chronic exposure to ozone pollution on nutritional traits of bean ( Phaseolus vulgaris L. cv. Borlotto Nano Lingua di Fuoco) seeds from plants grown in filtered and nonfiltered open-top chambers (OTCs) has been investigated. Results showed that, among seed macronutrients, ozone significantly raised total lipids, crude proteins, and dietary fiber and slightly decreased total free amino acid content, although with a significant reduction of asparagine, lysine, valine, methionine, and glycine, compensated by a conspicuous augmentation of ornithine and tryptophan. Phytosterol analysis showed a marked increase of beta-sitosterol, stigmasterol, and campesterol in seeds collected from nonfiltered OTCs. With regard to secondary metabolites, ozone exposure induced a slight increase of total polyphenol content, although causing a significant reduction of some flavonols (aglycone kaempferol and its 3-glucoside derivative) and hydroxycinnamates (caffeic, p-coumaric, and sinapic acids). Total anthocyanins decreased significantly, too. Nevertheless, ozone-exposed seeds showed higher antioxidant activity, with higher Trolox equivalent antioxidant capacity (TEAC) values than those measured in seeds collected from filtered air.
Collapse
Affiliation(s)
- Marcello Iriti
- Istituto di Patologia Vegetale, Universita di Milano, Milano, Italy.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Matyssek R, Sandermann H, Wieser G, Booker F, Cieslik S, Musselman R, Ernst D. The challenge of making ozone risk assessment for forest trees more mechanistic. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2008; 156:567-582. [PMID: 18571819 DOI: 10.1016/j.envpol.2008.04.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Revised: 04/24/2008] [Accepted: 04/27/2008] [Indexed: 05/26/2023]
Abstract
Upcoming decades will experience increasing atmospheric CO2 and likely enhanced O3 exposure which represents a risk for the carbon sink strength of forests, so that the need for cause-effect related O3 risk assessment increases. Although assessment will gain in reliability on an O3 uptake basis, risk is co-determined by the effective dose, i.e. the plant's sensitivity per O3 uptake. Recent progress in research on the molecular and metabolic control of the effective O3 dose is reported along with advances in empirically assessing O3 uptake at the whole-tree and stand level. Knowledge on both O3 uptake and effective dose (measures of stress avoidance and tolerance, respectively) needs to be understood mechanistically and linked as a pre-requisite before practical use of process-based O3 risk assessment can be implemented. To this end, perspectives are derived for validating and promoting new O3 flux-based modelling tools.
Collapse
Affiliation(s)
- R Matyssek
- Ecophysiology of Plants, Technische Universität München, Ecology, Am Hochanger 13, D-85354 Freising, Weihenstephan, Germany.
| | | | | | | | | | | | | |
Collapse
|
24
|
Heath RL. Modification of the biochemical pathways of plants induced by ozone: what are the varied routes to change? ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2008; 155:453-463. [PMID: 18456378 DOI: 10.1016/j.envpol.2008.03.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Accepted: 03/20/2008] [Indexed: 05/26/2023]
Abstract
When plants are observed under a low dose of ozone, some physiological and metabolic shifts occur. Barring extreme injury such as tissue damage or stomata closure, most of these disruptive changes are likely to have been initiated at the level of gene expression. The belief is oxidative products formed in ozone exposed leaves, e.g. hydrogen peroxide, are responsible for much of the biochemical adjustments. The first line of defense is a range of antioxidants, such as ascorbate and glutathione, but if this defense is overwhelmed, subsequent actions occur, similar to systemic acquired resistance or general wounding. Yet there are seemingly unrelated metabolic responses which are also triggered, such as early senescence. We discuss here the current understanding of gene control and signal transduction/control in order to increase our comprehension of how ozone alters the basic metabolism of plants and how plants counteract or cope with ozone.
Collapse
Affiliation(s)
- Robert L Heath
- Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA.
| |
Collapse
|
25
|
Ahsan N, Lee DG, Lee SH, Kang KY, Lee JJ, Kim PJ, Yoon HS, Kim JS, Lee BH. Excess copper induced physiological and proteomic changes in germinating rice seeds. CHEMOSPHERE 2007; 67:1182-93. [PMID: 17182080 DOI: 10.1016/j.chemosphere.2006.10.075] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Revised: 09/11/2006] [Accepted: 10/25/2006] [Indexed: 05/05/2023]
Abstract
Copper is an essential micronutrient for plants. Present at a high concentration in soil, copper is also regarded as a major toxicant to plant cells due to its potential inhibitory effects against many physiological and biochemical processes. The interference of germination-related proteins by heavy metals has not been well documented at the proteomic level. In the current study, physiological, biochemical and proteomic changes of germinating rice seeds were investigated under copper stress. Germination rate, shoot elongation, plant biomass, and water content were decreased, whereas accumulation of copper and TBARS content in seeds were increased significantly with increasing copper concentrations from 0.2mM to 1.5mM followed by germination. The SDS-PAGE showed the preliminary changes in the polypeptides patterns under copper stress. Protein profiles analyzed by two-dimensional electrophoresis (2-DE) revealed that 25 protein spots were differentially expressed in copper-treated samples. Among them, 18 protein spots were up-regulated and 7 protein spots were down-regulated. These differentially displayed proteins were identified by MALDI-TOF mass spectrometry. The up-regulation of some antioxidant and stress-related proteins such as glyoxalase I, peroxiredoxin, aldose reductase, and some regulatory proteins such as DnaK-type molecular chaperone, UlpI protease, and receptor-like kinase clearly indicated that excess copper generates oxidative stress that might be disruptive to other important metabolic processes. Moreover, down-regulation of key metabolic enzymes like alpha-amylase or enolase revealed that the inhibition of seed germinations after exposure to excess copper not only affects starvation in water uptake by seeds but also results in failure in the reserve mobilization processes. These results indicate a good correlation between the physiological and biochemical changes in germinating rice seeds exposed to excess copper.
Collapse
Affiliation(s)
- Nagib Ahsan
- Department of Animal Science and Biotechnology, College of Agriculture and Life Sciences, Kyungpook National University, Daegu 702-701, Republic of Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Jehnes S, Betz G, Bahnweg G, Haberer K, Sandermann H, Rennenberg H. Tree internal signalling and defence reactions under ozone exposure in sun and shade leaves of European beech (Fagus sylvatica L.) trees. PLANT BIOLOGY (STUTTGART, GERMANY) 2007; 9:253-64. [PMID: 17357019 DOI: 10.1055/s-2006-924650] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The influence of free-air ozone (O(3)) fumigation on the levels of gene transcripts and compounds of defence and signalling were analysed in leaves of adult beech trees from the "Kranzberg Forest" research site in 2003 and 2004. This includes the precursor of the stress hormone ethylene, ACC (1-aminocyclopropane-1-carboxylic acid), conjugated salicylic acid, lignin content as well as of the expression level of genes connected with oxidative stress and stress signalling. At this site mature beech trees were exposed to an enhanced O(3) regime by a free-air O(3) canopy exposure system. Levels of conjugated ACC and conjugated salicylic acid in leaves were increased under O (3) fumigation whereas lignin content was only slightly enhanced. Quantitative real-time RT-PCR (qRT-PCR) was performed on transcripts of genes connected with lignin, salicylic acid, and ethylene formation, the shikimate pathway, abscisic acid biosynthesis as well as with the antioxidative system. Genes which showed O(3)-dependent increases included FSCOMT (caffeic-acid O-methyltransferase) connected with lignin formation, the stress response genes FSACS2 (ACC synthase) and FSPR1 (PR10 - pathogenesis-related protein), as well as FSNCED1 (9-cis-epoxicarotenoid dioxygenase), the rate-limiting enzyme of the ABA synthesis. For FSNCED1 expression level, a significant O(3) effect was found with an 8-fold (sun) and 7-fold (shade) induction in July 2003 and a 3-fold and 2.5-fold induction in July 2004. While the observed effects were not continuous, elevated O(3) is concluded to have the potential to disrupt the defence and signalling system.
Collapse
Affiliation(s)
- S Jehnes
- Institute of Forest Botany and Tree Physiology, Albert Ludwigs University Freiburg, Georges-Köhler-Allee 053/054, 79110 Freiburg, Germany
| | | | | | | | | | | |
Collapse
|