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Wairich A, Ricachenevsky FK, Lee S. A tale of two metals: Biofortification of rice grains with iron and zinc. FRONTIERS IN PLANT SCIENCE 2022; 13:944624. [PMID: 36420033 PMCID: PMC9677123 DOI: 10.3389/fpls.2022.944624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 10/11/2022] [Indexed: 06/16/2023]
Abstract
Iron (Fe) and zinc (Zn) are essential micronutrients needed by virtually all living organisms, including plants and humans, for proper growth and development. Due to its capacity to easily exchange electrons, Fe is important for electron transport in mitochondria and chloroplasts. Fe is also necessary for chlorophyll synthesis. Zn is a cofactor for several proteins, including Zn-finger transcription factors and redox metabolism enzymes such as copper/Zn superoxide dismutases. In humans, Fe participates in oxygen transport, electron transport, and cell division whereas Zn is involved in nucleic acid metabolism, apoptosis, immunity, and reproduction. Rice (Oryza sativa L.) is one of the major staple food crops, feeding over half of the world's population. However, Fe and Zn concentrations are low in rice grains, especially in the endosperm, which is consumed as white rice. Populations relying heavily on rice and other cereals are prone to Fe and Zn deficiency. One of the most cost-effective solutions to this problem is biofortification, which increases the nutritional value of crops, mainly in their edible organs, without yield reductions. In recent years, several approaches were applied to enhance the accumulation of Fe and Zn in rice seeds, especially in the endosperm. Here, we summarize these attempts involving transgenics and mutant lines, which resulted in Fe and/or Zn biofortification in rice grains. We review rice plant manipulations using ferritin genes, metal transporters, changes in the nicotianamine/phytosiderophore pathway (including biosynthetic genes and transporters), regulators of Fe deficiency responses, and other mutants/overexpressing lines used in gene characterization that resulted in Fe/Zn concentration changes in seeds. This review also discusses research gaps and proposes possible future directions that could be important to increase the concentration and bioavailability of Fe and Zn in rice seeds without the accumulation of deleterious elements. We also emphasize the need for a better understanding of metal homeostasis in rice, the importance of evaluating yield components of plants containing transgenes/mutations under field conditions, and the potential of identifying genes that can be manipulated by gene editing and other nontransgenic approaches.
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Affiliation(s)
- Andriele Wairich
- Graduate Program in Molecular and Cellular Biology, Biotechnology Center, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Felipe K. Ricachenevsky
- Graduate Program in Molecular and Cellular Biology, Biotechnology Center, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
- Department of Botany, Institute of Biosciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Sichul Lee
- Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, South Korea
- Department of Agricultural Biotechnology, National Institute of Agricultural Science, Jeonju, South Korea
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Kumar V, Pandita S, Singh Sidhu GP, Sharma A, Khanna K, Kaur P, Bali AS, Setia R. Copper bioavailability, uptake, toxicity and tolerance in plants: A comprehensive review. CHEMOSPHERE 2021; 262:127810. [PMID: 32763578 DOI: 10.1016/j.chemosphere.2020.127810] [Citation(s) in RCA: 127] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/14/2020] [Accepted: 07/21/2020] [Indexed: 05/04/2023]
Abstract
Copper (Cu) is an essential element for humans and plants when present in lesser amount, while in excessive amounts it exerts detrimental effects. There subsists a narrow difference amid the indispensable, positive and detrimental concentration of Cu in living system, which substantially alters with Cu speciation, and form of living organisms. Consequently, it is vital to monitor its bioavailability, speciation, exposure levels and routes in the living organisms. The ingestion of Cu-laced food crops is the key source of this heavy metal toxicity in humans. Hence, it is necessary to appraise the biogeochemical behaviour of Cu in soil-plant system with esteem to their quantity and speciation. On the basis of existing research, this appraisal traces a probable connexion midst: Cu levels, sources, chemistry, speciation and bioavailability in the soil. Besides, the functions of protein transporters in soil-plant Cu transport, and the detrimental effect of Cu on morphological, physiological and nutrient uptake in plants has also been discussed in the current manuscript. Mechanisms related to detoxification strategies like antioxidative response and generation of glutathione and phytochelatins to combat Cu-induced toxicity in plants is discussed as well. We also delimits the Cu accretion in food crops and allied health perils from soils encompassing less or high Cu quantity. Finally, an overview of various techniques involved in the reclamation and restoration of Cu-contaminated soils has been provided.
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Affiliation(s)
- Vinod Kumar
- Department of Botany, Government Degree College, Ramban, Jammu, 182144, India.
| | - Shevita Pandita
- Department of Botany, University of Jammu, Jammu and Kashmir, India
| | - Gagan Preet Singh Sidhu
- Centre for Applied Biology in Environment Sciences, Kurukshetra University, Kurukshetra, 136119, India
| | - Anket Sharma
- State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, Hangzhou, 311300, China
| | - Kanika Khanna
- Independent Researcher, House No.282, Lane no. 3, Friends Colony, Opposite DAV College, Jalandhar, 144008, Punjab, India
| | - Parminder Kaur
- Independent Researcher, House No. 472, Ward No. 8, Dhariwal, Gurdaspur, 143519, Punjab, India
| | - Aditi Shreeya Bali
- Department of Botany, Dyal Singh College, Karnal, Haryana, 132001, India
| | - Raj Setia
- Punjab Remote Sensing Centre, Ludhiana, India
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Navarro BB, Del Frari BK, Dias PVDC, Lemainski LE, Mario RB, Ponte LR, Goergen A, Tarouco CP, Neves VM, Dressler VL, Fett JP, Brunetto G, Sperotto RA, Nicoloso FT, Ricachenevsky FK. The copper economy response is partially conserved in rice (Oryza sativa L.). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 158:113-124. [PMID: 33307423 DOI: 10.1016/j.plaphy.2020.11.051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 11/27/2020] [Indexed: 06/12/2023]
Abstract
Copper (Cu) is an essential element for plants, especially in photosynthesis, as it is required for plastocyanin function in electron transfer reactions at thylakoid membranes. In Arabidopsis thaliana, Cu deficiency leads to the Cu economy response, in which plants prioritize Cu usage by plastocyanin in detriment of non-essential cupric proteins. In rice (Oryza sativa), however, this response has not been characterized. Rice OsHMA5 is a Cu xylem-loading transporter involved in Cu translocation from roots to shoots, as suggested by the analysis of oshma5 mutant plants. Aiming to understand how rice plants respond to Cu deficiency and how decreased Cu translocation to shoots can affect this response, we characterized the physiological and molecular responses of WT and oshma5 plants under control and Cu deficiency treatments. We found evidence that shoots of oshma5 plants are more prone to Cu deficiency compared to shoots of WT plants, as demonstrated by decreased chlorophyll and Cu concentrations, and electron transport rate. Gene expression analysis revealed that Cu high-affinity transporters OsCOPT1 and OsCOPT5, along with a set of miRNAs and three Cu/Zn superoxide dismutases are responsive to Cu deficiency in both WT and oshma5 plants, suggesting their involvement in the Cu economy response. However, Fe superoxide dismutase was not up-regulated in rice, indicating a difference compared to the A. thaliana Cu economy model. Therefore, we provide evidence for a partially conserved Cu economy response in rice, in comparison to A. thaliana.
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Affiliation(s)
- Bruno Bachiega Navarro
- Programa de Pós-Graduação em Agrobiologia, Universidade Federal de Santa Maria, Santa Maria, Brazil
| | - Bianca Knebel Del Frari
- Programa de Pós-Graduação em Agronomia, Universidade Federal de Santa Maria, Santa Maria, Brazil
| | | | | | | | - Lucas Roani Ponte
- Curso de Agronomia, Universidade Federal de Santa Maria, Santa Maria, Brazil
| | - Andrei Goergen
- Curso de Agronomia, Universidade Federal de Santa Maria, Santa Maria, Brazil
| | | | | | | | - Janette Palma Fett
- Departamento de Botânica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Gustavo Brunetto
- Departamento de Solos, Programa de Pós-Graduação em Ciências do Solo, Universidade Federal de Santa Maria, Santa Maria, Brazil
| | - Raul Antonio Sperotto
- Programa de Pós-Graduação em Biotecnologia, Universidade do Vale do Taquari - Univates, Lajeado, Brazil
| | - Fernando Teixeira Nicoloso
- Programa de Pós-Graduação em Agrobiologia, Universidade Federal de Santa Maria, Santa Maria, Brazil; Programa de Pós-Graduação em Agronomia, Universidade Federal de Santa Maria, Santa Maria, Brazil
| | - Felipe Klein Ricachenevsky
- Programa de Pós-Graduação em Agrobiologia, Universidade Federal de Santa Maria, Santa Maria, Brazil; Departamento de Botânica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
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Bernal M, Krämer U. Involvement of Arabidopsis Multi-Copper Oxidase-Encoding LACCASE12 in Root-to-Shoot Iron Partitioning: A Novel Example of Copper-Iron Crosstalk. FRONTIERS IN PLANT SCIENCE 2021; 12:688318. [PMID: 34707625 PMCID: PMC8544784 DOI: 10.3389/fpls.2021.688318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 08/23/2021] [Indexed: 05/17/2023]
Abstract
Numerous central biological processes depend on the participation of the essential elements iron (Fe) or copper (Cu), including photosynthesis, respiration, cell wall remodeling and oxidative stress protection. Yet, both Fe and Cu metal cations can become toxic when accumulated in excess. Because of the potent ligand-binding and redox chemistries of these metals, there is a need for the tight and combined homeostatic control of their uptake and distribution. Several known examples pinpoint an inter-dependence of Fe and Cu homeostasis in eukaryotes, mostly in green algae, yeast and mammals, but this is less well understood in multicellular plants to date. In Arabidopsis, Cu deficiency causes secondary Fe deficiency, and this is associated with reduced in vitro ferroxidase activity and decreased root-to-shoot Fe translocation. Here we summarize the current knowledge of the cross-talk between Cu and Fe homeostasis and present a partial characterization of LACCASE12 (LAC12) that encodes a member of the multicopper oxidase (MCO) protein family in Arabidopsis. LAC12 transcript levels increase under Fe deficiency. The phenotypic characterization of two mutants carrying T-DNA insertions suggests a role of LAC12 in root-to-shoot Fe partitioning and in maintaining growth on Fe-deficient substrates. A molecular understanding of the complex interactions between Fe and Cu will be important for combating Fe deficiency in crops and for advancing biofortification approaches.
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Affiliation(s)
- María Bernal
- Department of Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
- Department of Plant Nutrition, Estación Experimental de Aula Dei-CSIC, Zaragoza, Spain
- *Correspondence: María Bernal,
| | - Ute Krämer
- Department of Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
- Ute Krämer,
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Rather BA, Masood A, Sehar Z, Majid A, Anjum NA, Khan NA. Mechanisms and Role of Nitric Oxide in Phytotoxicity-Mitigation of Copper. FRONTIERS IN PLANT SCIENCE 2020; 11:675. [PMID: 32547583 PMCID: PMC7274197 DOI: 10.3389/fpls.2020.00675] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 04/29/2020] [Indexed: 05/07/2023]
Abstract
Phytotoxicity of metals significantly contributes to the major loss in agricultural productivity. Among all the metals, copper (Cu) is one of essential metals, where it exhibits toxicity only at its supra-optimal level. Elevated Cu levels affect plants developmental processes from initiation of seed germination to the senescence, photosynthetic functions, growth and productivity. The use of plant growth regulators/phytohormones and other signaling molecules is one of major approaches for reversing Cu-toxicity in plants. Nitric oxide (NO) is a versatile and bioactive gaseous signaling molecule, involved in major physiological and molecular processes in plants. NO modulates responses of plants grown under optimal conditions or to multiple stress factors including elevated Cu levels. The available literature in this context is centered mainly on the role of NO in combating Cu stress with partial discussion on underlying mechanisms. Considering the recent reports, this paper: (a) overviews Cu uptake and transport; (b) highlights the major aspects of Cu-toxicity on germination, photosynthesis, growth, phenotypic changes and nutrient-use-efficiency; (c) updates on NO as a major signaling molecule; and (d) critically appraises the Cu-significance and mechanisms underlying NO-mediated alleviation of Cu-phytotoxicity. The outcome of the discussion may provide important clues for future research on NO-mediated mitigation of Cu-phytotoxicity.
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Perea-García A, Andrés-Bordería A, Vera-Sirera F, Pérez-Amador MA, Puig S, Peñarrubia L. Deregulated High Affinity Copper Transport Alters Iron Homeostasis in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2020; 11:1106. [PMID: 32793263 PMCID: PMC7390907 DOI: 10.3389/fpls.2020.01106] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 07/06/2020] [Indexed: 05/08/2023]
Abstract
The present work describes the effects on iron homeostasis when copper transport was deregulated in Arabidopsis thaliana by overexpressing high affinity copper transporters COPT1 and COPT3 (COPTOE ). A genome-wide analysis conducted on COPT1OE plants, highlighted that iron homeostasis gene expression was affected under both copper deficiency and excess. Among the altered genes were those encoding the iron uptake machinery and their transcriptional regulators. Subsequently, COPTOE seedlings contained less iron and were more sensitive than controls to iron deficiency. The deregulation of copper (I) uptake hindered the transcriptional activation of the subgroup Ib of basic helix-loop-helix (bHLH-Ib) factors under copper deficiency. Oppositely, copper excess inhibited the expression of the master regulator FIT but activated bHLH-Ib expression in COPTOE plants, in both cases leading to the lack of an adequate iron uptake response. As copper increased in the media, iron (III) was accumulated in roots, and the ratio iron (III)/iron (II) was increased in COPTOE plants. Thus, iron (III) overloading in COPTOE roots inhibited local iron deficiency responses, aimed to metal uptake from soil, leading to a general lower iron content in the COPTOE seedlings. These results emphasized the importance of appropriate spatiotemporal copper uptake for iron homeostasis under non-optimal copper supply. The understanding of the role of copper uptake in iron metabolism could be applied for increasing crops resistance to iron deficiency.
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Affiliation(s)
- Ana Perea-García
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Amparo Andrés-Bordería
- Departament de Bioquímica i Biologia Molecular and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, Burjassot, Valencia, Spain
| | - Francisco Vera-Sirera
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Científicas (CSIC)—Universidad Politécnica de Valencia (UPV), Valencia, Spain
| | - Miguel Angel Pérez-Amador
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Científicas (CSIC)—Universidad Politécnica de Valencia (UPV), Valencia, Spain
| | - Sergi Puig
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Lola Peñarrubia
- Departament de Bioquímica i Biologia Molecular and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, Burjassot, Valencia, Spain
- *Correspondence: Lola Peñarrubia,
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Zeng Q, Ling Q, Wu J, Yang Z, Liu R, Qi Y. Excess Copper-Induced Changes in Antioxidative Enzyme Activity, Mineral Nutrient Uptake and Translocation in Sugarcane Seedlings. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2019; 103:834-840. [PMID: 31676938 DOI: 10.1007/s00128-019-02735-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 10/21/2019] [Indexed: 06/10/2023]
Abstract
Sugarcane is a potential species for use in heavy metal remediation. To analyze the effect of excess copper on sugarcane, the biomass, mineral nutrient content and activities of antioxidative enzymes were measured under copper stress. The results revealed that the biomass of roots and shoots significantly decreased with increasing copper concentration in solution. Most copper accumulated in the roots, and the translocation factor of copper decreased with an increase in copper stress. The MDA content in sugarcane roots notably increased under copper stress. The POD activity in sugarcane roots increased, and CAT activity decreased under copper stress. The Zn, Fe and Mn contents in shoots increased significantly under 200 μmol L-1 Cu2+ treatments. The Zn and Mg contents in roots notably decreased under copper stress, while the Zn and Mg translocation factors increased. These results indicated that the increase in POD activity and the modification of mineral nutrient uptake and transfer might play an important role in reducing the detrimental effects of excess copper.
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Affiliation(s)
- Qiaoying Zeng
- Guangdong Key Lab of Sugarcane Improvement and Biorefinery, Research Center for Sugarcane Industry Engineering Technology of Light Industry of China, Guangdong Provincial Bioengineering Institute, Guangzhou Sugarcane Industry Research Institute, Guangzhou, 510316, China
| | - Qiuping Ling
- Guangdong Key Lab of Sugarcane Improvement and Biorefinery, Research Center for Sugarcane Industry Engineering Technology of Light Industry of China, Guangdong Provincial Bioengineering Institute, Guangzhou Sugarcane Industry Research Institute, Guangzhou, 510316, China
| | - Jiayun Wu
- Guangdong Key Lab of Sugarcane Improvement and Biorefinery, Research Center for Sugarcane Industry Engineering Technology of Light Industry of China, Guangdong Provincial Bioengineering Institute, Guangzhou Sugarcane Industry Research Institute, Guangzhou, 510316, China
| | - Zhanduan Yang
- Guangdong Key Lab of Sugarcane Improvement and Biorefinery, Research Center for Sugarcane Industry Engineering Technology of Light Industry of China, Guangdong Provincial Bioengineering Institute, Guangzhou Sugarcane Industry Research Institute, Guangzhou, 510316, China
| | - Rui Liu
- Guangdong Key Lab of Sugarcane Improvement and Biorefinery, Research Center for Sugarcane Industry Engineering Technology of Light Industry of China, Guangdong Provincial Bioengineering Institute, Guangzhou Sugarcane Industry Research Institute, Guangzhou, 510316, China
| | - Yongwen Qi
- Guangdong Key Lab of Sugarcane Improvement and Biorefinery, Research Center for Sugarcane Industry Engineering Technology of Light Industry of China, Guangdong Provincial Bioengineering Institute, Guangzhou Sugarcane Industry Research Institute, Guangzhou, 510316, China.
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Belykh ES, Maystrenko TA, Velegzhaninov IO. Recent Trends in Enhancing the Resistance of Cultivated Plants to Heavy Metal Stress by Transgenesis and Transcriptional Programming. Mol Biotechnol 2019; 61:725-741. [DOI: 10.1007/s12033-019-00202-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Hippler FWR, Mattos-Jr D, Boaretto RM, Williams LE. Copper excess reduces nitrate uptake by Arabidopsis roots with specific effects on gene expression. JOURNAL OF PLANT PHYSIOLOGY 2018; 228:158-165. [PMID: 29933138 PMCID: PMC6090090 DOI: 10.1016/j.jplph.2018.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 06/09/2018] [Accepted: 06/10/2018] [Indexed: 05/09/2023]
Abstract
Nitrate uptake by plants is mediated by specific transport proteins in roots (NRTs), which are also dependent on the activity of proton pumps that energize the reaction. Nitrogen (N) metabolism in plants is sensitive to copper (Cu) toxicity conditions. To understand how Cu affects the uptake and assimilation processes, this study assesses the inhibitory effects of elevated Cu levels on the expression of genes related to N absorption, transport and assimilation in roots of Arabidopsis. Plants were grown hydroponically for 45 days, being exposed to a range of Cu concentrations in the last 72 h or alternatively exposed to 5.0 μM Cu for the last 15 days. High Cu levels decreased the uptake and accumulation of N in plants. It down-regulated the expression of genes encoding nitrate reductase (NR1), low-affinity nitrate transporters (NRT1 family) and bZIP transcription factors (TGA1 and TGA4) that regulate the expression of nitrate transporters. Cu toxicity also specifically down-regulated the plasma membrane proton pump, AHA2, whilst having little effect on AHA1 and AHA5. In contrast, there was an up-regulation of high-affinity nitrate transporters from the NRT2 family when exposed to medium level of Cu excess, but this was insufficient for restoring N absorption by roots to control levels. These results demonstrate that plants display specific responses to Cu toxicity, modulating the expression of particular genes related to nitrate uptake, such as low-affinity nitrate transporters and proton pumps.
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Affiliation(s)
- Franz W R Hippler
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico (IAC), Rod. Anhanguera, km 158, CP 04, CEP 13490-970, Cordeirópolis, SP, Brazil; University of Southampton, Biological Sciences, Building 85, Highfield, Southampton SO17 1BJ, United Kingdom.
| | - Dirceu Mattos-Jr
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico (IAC), Rod. Anhanguera, km 158, CP 04, CEP 13490-970, Cordeirópolis, SP, Brazil
| | - Rodrigo M Boaretto
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico (IAC), Rod. Anhanguera, km 158, CP 04, CEP 13490-970, Cordeirópolis, SP, Brazil
| | - Lorraine E Williams
- University of Southampton, Biological Sciences, Building 85, Highfield, Southampton SO17 1BJ, United Kingdom.
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Hippler FWR, Petená G, Boaretto RM, Quaggio JA, Azevedo RA, Mattos-Jr D. Mechanisms of copper stress alleviation in Citrus trees after metal uptake by leaves or roots. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:13134-13146. [PMID: 29488204 DOI: 10.1007/s11356-018-1529-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 02/13/2018] [Indexed: 04/15/2023]
Abstract
Nutritional disorders caused by copper (Cu) have affected citrus orchards. Since Cu is foliar sprayed as a pesticide to control citrus diseases, this metal accumulates in the soil. Thereby, we evaluated the effects of Cu leaf absorption after spray of different metal sources, as well as roots absorption on growth, nutritional status, and oxidative stress of young sweet orange trees. Two experiments were carried out under greenhouse conditions. The first experiment was set up with varying Cu levels to the soil (nil Cu, 0.5, 2.0, 4.0 and 8.0 g of Cu per plant as CuSO4.5H2O), whereas the second experiment with Cu application via foliar sprays (0.5 and 2.0 g of Cu per plant) and comparing two metal sources (CuSO4.5H2O or Cu(OH)2). Copper was mainly accumulated in roots with soil supply, but an increase of oxidative stress levels was observed in leaves. On the other hand, Cu concentrations were higher in leaves that received foliar sprays, mainly as Cu(OH)2. However, when sulfate was foliar sprayed, plants exhibited more symptoms of injuries in the canopy with decreased chlorophyll contents and increased hydrogen peroxide and lipid peroxidation levels. Copper toxicity was characterized by sap leakage from the trunk and twigs, which is the first report of this specific Cu excess symptom in woody trees. Despite plants with 8.0 g of Cu soil-applied exhibiting the sap leakage, growth of new plant parts was more vigorous with lower oxidative stress levels and injuries compared to those with 4.0 g of Cu soil-applied (without sap leakage). With the highest level of Cu applied via foliar as sulfate, Cu was eliminated by plant roots, increasing the rhizospheric soil metal levels. Despite citrus likely exhibiting different mechanisms to reduce the damages caused by metal toxicity, such as responsive enzymatic antioxidant system, metal accumulation in the roots, and metal exclusion by roots, excess Cu resulted in damages on plant growth and metabolism when the metal was taken up either by roots or leaves.
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Affiliation(s)
- Franz Walter Rieger Hippler
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico (IAC), Rod. Anhanguera, km 158, CP 04, Cordeirópolis, SP, 13490-970, Brazil.
- Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo (USP), CP 09, Piracicaba, SP, 13418-900, Brazil.
| | - Guilherme Petená
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico (IAC), Rod. Anhanguera, km 158, CP 04, Cordeirópolis, SP, 13490-970, Brazil
| | - Rodrigo Marcelli Boaretto
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico (IAC), Rod. Anhanguera, km 158, CP 04, Cordeirópolis, SP, 13490-970, Brazil
| | - José Antônio Quaggio
- Centro de Solos e Recursos Ambientais, Instituto Agronômico (IAC), Av. Barão de Itapura, 1481, CP 28, Campinas, SP, 13020-902, Brazil
| | - Ricardo Antunes Azevedo
- Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo (USP), CP 09, Piracicaba, SP, 13418-900, Brazil
| | - Dirceu Mattos-Jr
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico (IAC), Rod. Anhanguera, km 158, CP 04, Cordeirópolis, SP, 13490-970, Brazil.
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