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Zsigmond L, Juhász-Erdélyi A, Valkai I, Aleksza D, Rigó G, Kant K, Szepesi Á, Fiorani F, Körber N, Kovács L, Szabados L. Mitochondrial complex I subunit NDUFS8.2 modulates responses to stresses associated with reduced water availability. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 208:108466. [PMID: 38428158 DOI: 10.1016/j.plaphy.2024.108466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 02/07/2024] [Accepted: 02/22/2024] [Indexed: 03/03/2024]
Abstract
Mitochondria are important sources of energy in plants and are implicated in coordination of a number of metabolic and physiological processes including stabilization of redox balance, synthesis and turnover of a number of metabolites, and control of programmed cell death. Mitochondrial electron transport chain (mETC) is the backbone of the energy producing process which can influence other processes as well. Accumulating evidence suggests that mETC can affect responses to environmental stimuli and modulate tolerance to extreme conditions such as drought or salinity. Screening for stress responses of 13 Arabidopsis mitochondria-related T-DNA insertion mutants, we identified ndufs8.2-1 which has an increased ability to withstand osmotic and oxidative stresses compared to wild type plants. Insertion in ndufs8.2-1 disrupted the gene that encodes the NADH dehydrogenase [ubiquinone] fragment S subunit 8 (NDUFS8) a component of Complex I of mETC. ndufs8.2-1 tolerated reduced water availability, retained photosynthetic activity and recovered from severe water stress with higher efficiency compared to wild type plants. Several mitochondrial functions were altered in the mutant including oxygen consumption, ROS production, ATP and ADP content as well as activities of genes encoding alternative oxidase 1A (AOX1A) and various alternative NAD(P)H dehydrogenases (ND). Our results suggest that in the absence of NDUFS8.2 stress-induced ROS generation is restrained leading to reduced oxidative damage and improved tolerance to water deficiency. mETC components can be implicated in redox and energy homeostasis and modulate responses to stresses associated with reduced water availability.
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Affiliation(s)
- Laura Zsigmond
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary.
| | - Annabella Juhász-Erdélyi
- Department of Plant Biology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Ildikó Valkai
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary
| | - Dávid Aleksza
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary
| | - Gábor Rigó
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary
| | - Kamal Kant
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary
| | - Ágnes Szepesi
- Department of Plant Biology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Fabio Fiorani
- Institute of Bio- and Geo-Sciences, IBG2: Plant Sciences, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Niklas Körber
- Nunhems - BASF Vegetable Seeds, Department of Data Science and Technology, Roermond, Netherlands
| | - László Kovács
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary
| | - László Szabados
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary
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Kaziuk FD, Furlanetto ALDDM, Dos Santos ALW, Floh EIS, Donatti L, Merlin Rocha ME, Fortes F, Martinez GR, Cadena SMSC. The metabolic response of Araucaria angustifolia embryogenic cells to heat stress is associated with their maturation potential. FUNCTIONAL PLANT BIOLOGY : FPB 2023; 50:1010-1027. [PMID: 37743049 DOI: 10.1071/fp22272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 08/30/2023] [Indexed: 09/26/2023]
Abstract
Araucaria angustifolia is a critically endangered species and its distribution can be affected by an increase in temperature. In this study, we evaluated the effects of heat stress (30°C) on Araucaria angustifolia cell lines responsive (SE1) and non-responsive (SE6) to the development of somatic embryos. The viability of both cell lines was reduced by heat stress and mitochondria were the organelles most affected. Heat stress for 24h increased the reactive oxygen species (ROS) levels in SE1 cells, followed by a reduction at 48 and 72h. In SE6 cells, an increase occurred after 24 and 48h of stress, returning to control levels at 72h. H2 O2 levels were increased after 24h for both SE1 and SE6 cells, being higher for SE6. Interestingly, at 48 and 72h, H2 O2 levels decreased in SE1 cells, while in SE6, the values returned to the control levels. The respiration of SE6 cells in the presence of oxidisable substrates was inhibited by heat stress, in agreement with the high lipid peroxidation levels. The AaSERK1 gene was identified in both cultures, with greater expression in the SE1 line. Heat stress for 24 and 48h increased gene expression only in this cell line. The activity of peroxidase, superoxide dismutase and enzymes of the glutathione/ascorbate cycle was increased in both cell lines subjected to heat stress. Catalase activity was increased only in SE6 cells at 72h of exposure. These results show that responsive SE1 cells can modulate ROS levels more efficiently than SE6 when these cells are stressed by heat. This ability may be related to the maturation capacity of these cells.
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Affiliation(s)
- Fernando Diego Kaziuk
- Department of Biochemistry and Molecular Biology, Federal University of Paraná, Curitiba, Paraná, Brazil
| | | | | | | | - Lucelia Donatti
- Department of Cellular Biology, Federal University of Paraná, Curitiba, Paraná, Brazil
| | - Maria Eliane Merlin Rocha
- Department of Biochemistry and Molecular Biology, Federal University of Paraná, Curitiba, Paraná, Brazil
| | - Fabiane Fortes
- Department of Biology, State University of Paraná, União da Vitória, Paraná, Brazil
| | - Glaucia Regina Martinez
- Department of Biochemistry and Molecular Biology, Federal University of Paraná, Curitiba, Paraná, Brazil
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Negi NP, Prakash G, Narwal P, Panwar R, Kumar D, Chaudhry B, Rustagi A. The calcium connection: exploring the intricacies of calcium signaling in plant-microbe interactions. FRONTIERS IN PLANT SCIENCE 2023; 14:1248648. [PMID: 37849843 PMCID: PMC10578444 DOI: 10.3389/fpls.2023.1248648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 08/24/2023] [Indexed: 10/19/2023]
Abstract
The process of plant immune response is orchestrated by intracellular signaling molecules. Since plants are devoid of a humoral system, they develop extensive mechanism of pathogen recognition, signal perception, and intricate cell signaling for their protection from biotic and abiotic stresses. The pathogenic attack induces calcium ion accumulation in the plant cells, resulting in calcium signatures that regulate the synthesis of proteins of defense system. These calcium signatures induct different calcium dependent proteins such as calmodulins (CaMs), calcineurin B-like proteins (CBLs), calcium-dependent protein kinases (CDPKs) and other signaling molecules to orchestrate the complex defense signaling. Using advanced biotechnological tools, the role of Ca2+ signaling during plant-microbe interactions and the role of CaM/CMLs and CDPKs in plant defense mechanism has been revealed to some extent. The Emerging perspectives on calcium signaling in plant-microbe interactions suggest that this complex interplay could be harnessed to improve plant resistance against pathogenic microbes. We present here an overview of current understanding in calcium signatures during plant-microbe interaction so as to imbibe a future direction of research.
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Affiliation(s)
- Neelam Prabha Negi
- University Institute of Biotechnology, Chandigarh University, Mohali, India
| | - Geeta Prakash
- Department of Botany, Gargi College, New Delhi, India
| | - Parul Narwal
- University Institute of Biotechnology, Chandigarh University, Mohali, India
| | - Ruby Panwar
- Department of Botany, Gargi College, New Delhi, India
| | - Deepak Kumar
- Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
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Matos IF, Morales LMM, Santana DB, Silva GMC, Gomes MMDA, Ayub RA, Costa JH, de Oliveira JG. Ascorbate synthesis as an alternative electron source for mitochondrial respiration: Possible implications for the plant performance. FRONTIERS IN PLANT SCIENCE 2022; 13:987077. [PMID: 36507441 PMCID: PMC9727407 DOI: 10.3389/fpls.2022.987077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 10/31/2022] [Indexed: 06/01/2023]
Abstract
The molecule vitamin C, in the chemical form of ascorbic acid (AsA), is known to be essential for the metabolism of humans and animals. Humans do not produce AsA, so they depend on plants as a source of vitamin C for their food. The AsA synthesis pathway occurs partially in the cytosol, but the last oxidation step is physically linked to the respiratory chain of plant mitochondria. This oxidation step is catalyzed by l-galactono-1,4-lactone dehydrogenase (l-GalLDH). This enzyme is not considered a limiting step for AsA production; however, it presents a distinguishing characteristic: the l-GalLDH can introduce electrons directly into the respiratory chain through cytochrome c (Cytc) and therefore can be considered an extramitochondrial electron source that bypasses the phosphorylating Complex III. The use of Cytc as electron acceptor has been debated in terms of its need for AsA synthesis, but little has been said in relation to its impact on the functioning of the respiratory chain. This work seeks to offer a new view about the possible changes that result of the link between AsA synthesis and the mitochondrial respiration. We hypothesized that some physiological alterations related to low AsA may be not only explained by the deficiency of this molecule but also by the changes in the respiratory function. We discussed some findings showing that respiratory mutants contained changes in AsA synthesis. Besides, recent works that also indicate that the excessive electron transport via l-GalLDH enzyme may affect other respiratory pathways. We proposed that Cytc reduction by l-GalLDH may be part of an alternative respiratory pathway that is active during AsA synthesis. Also, it is proposed that possible links of this pathway with other pathways of alternative electron transport in plant mitochondria may exist. The review suggests potential implications of this relationship, particularly for situations of stress. We hypothesized that this pathway of alternative electron input would serve as a strategy for adaptation of plant respiration to changing conditions.
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Affiliation(s)
- Isabelle Faria Matos
- Plant Genetic Breeding Laboratory, Center for Agricultural Sciences and Technologies, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, RJ, Brazil
| | | | - Diederson Bortolini Santana
- Plant Genetic Breeding Laboratory, Center for Agricultural Sciences and Technologies, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, RJ, Brazil
| | - Gláucia Michelle Cosme Silva
- Plant Genetic Breeding Laboratory, Center for Agricultural Sciences and Technologies, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, RJ, Brazil
| | - Mara Menezes de Assis Gomes
- Plant Genetic Breeding Laboratory, Center for Agricultural Sciences and Technologies, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, RJ, Brazil
| | - Ricardo Antônio Ayub
- Laboratory of Biotechnology Applied to Fruit Growing, Department of Phytotechny and Phytosanitary, Universidade Estadual de Ponta Grossa, Ponta Grossa, PR, Brazil
| | - José Hélio Costa
- Functional Genomics and Bioinformatics, Department of Biochemistry and Molecular Biology, Universidade Federal do Ceará, Fortaleza, CE, Brazil
- Non-Institutional Competence Focus (NICFocus) ‘Functional Cell Reprogramming and Organism Plasticity’ (FunCROP), coordinated from Foros de Vale de Figueira, Alentejo, Portugal
| | - Jurandi Gonçalves de Oliveira
- Plant Genetic Breeding Laboratory, Center for Agricultural Sciences and Technologies, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, RJ, Brazil
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Sweetman C, Waterman CD, Wong DC, Day DA, Jenkins CL, Soole KL. Altering the balance between AOX1A and NDB2 expression affects a common set of transcripts in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2022; 13:876843. [PMID: 36466234 PMCID: PMC9716356 DOI: 10.3389/fpls.2022.876843] [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: 02/15/2022] [Accepted: 10/24/2022] [Indexed: 06/17/2023]
Abstract
Stress-responsive components of the mitochondrial alternative electron transport pathway have the capacity to improve tolerance of plants to abiotic stress, particularly the alternative oxidase AOX1A but also external NAD(P)H dehydrogenases such as NDB2, in Arabidopsis. NDB2 and AOX1A can cooperate to entirely circumvent the classical electron transport chain in Arabidopsis mitochondria. Overexpression of AOX1A or NDB2 alone can have slightly negative impacts on plant growth under optimal conditions, while simultaneous overexpression of NDB2 and AOX1A can reverse these phenotypic effects. We have taken a global transcriptomic approach to better understand the molecular shifts that occur due to overexpression of AOX1A alone and with concomitant overexpression of NDB2. Of the transcripts that were significantly up- or down- regulated in the AOX1A overexpression line compared to wild type (410 and 408, respectively), the majority (372 and 337, respectively) reverted to wild type levels in the dual overexpression line. Several mechanisms for the AOX1A overexpression phenotype are proposed based on the functional classification of these 709 genes, which can be used to guide future experiments. Only 28 genes were uniquely up- or down-regulated when NDB2 was overexpressed in the AOX1A overexpression line. On the other hand, many unique genes were deregulated in the NDB2 knockout line. Furthermore, several changes in transcript abundance seen in the NDB2 knockout line were consistent with changes in the AOX1A overexpression line. The results suggest that an imbalance in AOX1A:NDB2 protein levels caused by under- or over-expression of either component, triggers a common set of transcriptional responses that may be important in mitochondrial redox regulation. The most significant changes were transcripts associated with photosynthesis, secondary metabolism and oxidative stress responses.
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Affiliation(s)
- Crystal Sweetman
- College of Science & Engineering, Flinders University, Bedford Park, SA, Australia
| | | | - Darren C.J. Wong
- College of Science, Australian National University, Canberra, ACT, Australia
| | - David A. Day
- College of Science & Engineering, Flinders University, Bedford Park, SA, Australia
| | - Colin L.D. Jenkins
- College of Science & Engineering, Flinders University, Bedford Park, SA, Australia
| | - Kathleen L. Soole
- College of Science & Engineering, Flinders University, Bedford Park, SA, Australia
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Barreto P, Koltun A, Nonato J, Yassitepe J, Maia IDG, Arruda P. Metabolism and Signaling of Plant Mitochondria in Adaptation to Environmental Stresses. Int J Mol Sci 2022; 23:ijms231911176. [PMID: 36232478 PMCID: PMC9570015 DOI: 10.3390/ijms231911176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 08/29/2022] [Accepted: 09/02/2022] [Indexed: 11/16/2022] Open
Abstract
The interaction of mitochondria with cellular components evolved differently in plants and mammals; in plants, the organelle contains proteins such as ALTERNATIVE OXIDASES (AOXs), which, in conjunction with internal and external ALTERNATIVE NAD(P)H DEHYDROGENASES, allow canonical oxidative phosphorylation (OXPHOS) to be bypassed. Plant mitochondria also contain UNCOUPLING PROTEINS (UCPs) that bypass OXPHOS. Recent work revealed that OXPHOS bypass performed by AOXs and UCPs is linked with new mechanisms of mitochondrial retrograde signaling. AOX is functionally associated with the NO APICAL MERISTEM transcription factors, which mediate mitochondrial retrograde signaling, while UCP1 can regulate the plant oxygen-sensing mechanism via the PRT6 N-Degron. Here, we discuss the crosstalk or the independent action of AOXs and UCPs on mitochondrial retrograde signaling associated with abiotic stress responses. We also discuss how mitochondrial function and retrograde signaling mechanisms affect chloroplast function. Additionally, we discuss how mitochondrial inner membrane transporters can mediate mitochondrial communication with other organelles. Lastly, we review how mitochondrial metabolism can be used to improve crop resilience to environmental stresses. In this respect, we particularly focus on the contribution of Brazilian research groups to advances in the topic of mitochondrial metabolism and signaling.
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Affiliation(s)
- Pedro Barreto
- Departamento de Ciências Químicas e Biológicas, Instituto de Biociências, Universidade Estadual Paulista, Botucatu 18618-970, Brazil
| | - Alessandra Koltun
- Genomics for Climate Change Research Center, Universidade Estadual de Campinas, Campinas 13083-875, Brazil
- Departamento de Genética e Evolução, Instituto de Biologia, Universidade Estadual de Campinas, Campinas 13083-862, Brazil
| | - Juliana Nonato
- Genomics for Climate Change Research Center, Universidade Estadual de Campinas, Campinas 13083-875, Brazil
- Departamento de Genética e Evolução, Instituto de Biologia, Universidade Estadual de Campinas, Campinas 13083-862, Brazil
| | - Juliana Yassitepe
- Genomics for Climate Change Research Center, Universidade Estadual de Campinas, Campinas 13083-875, Brazil
- Departamento de Genética e Evolução, Instituto de Biologia, Universidade Estadual de Campinas, Campinas 13083-862, Brazil
- Embrapa Agricultura Digital, Campinas 13083-886, Brazil
| | - Ivan de Godoy Maia
- Departamento de Ciências Químicas e Biológicas, Instituto de Biociências, Universidade Estadual Paulista, Botucatu 18618-970, Brazil
| | - Paulo Arruda
- Genomics for Climate Change Research Center, Universidade Estadual de Campinas, Campinas 13083-875, Brazil
- Departamento de Genética e Evolução, Instituto de Biologia, Universidade Estadual de Campinas, Campinas 13083-862, Brazil
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas 13083-875, Brazil
- Correspondence:
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Oh GGK, O’Leary BM, Signorelli S, Millar AH. Alternative oxidase (AOX) 1a and 1d limit proline-induced oxidative stress and aid salinity recovery in Arabidopsis. PLANT PHYSIOLOGY 2022; 188:1521-1536. [PMID: 34919733 PMCID: PMC8896607 DOI: 10.1093/plphys/kiab578] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 11/12/2021] [Indexed: 05/24/2023]
Abstract
Proline (Pro) catabolism and reactive oxygen species production have been linked in mammals and Caenorhabditis elegans, while increases in leaf respiration rate follow Pro exposure in plants. Here, we investigated how alternative oxidases (AOXs) of the mitochondrial electron transport chain accommodate the large, atypical flux resulting from Pro catabolism and limit oxidative stress during Pro breakdown in mature Arabidopsis (Arabidopsis thaliana) leaves. Following Pro treatment, AOX1a and AOX1d accumulate at transcript and protein levels, with AOX1d approaching the level of the typically dominant AOX1a isoform. We therefore sought to determine the function of both AOX isoforms under Pro respiring conditions. Oxygen consumption rate measurements in aox1a and aox1d leaves suggested these AOXs can functionally compensate for each other to establish enhanced AOX catalytic capacity in response to Pro. Generation of aox1a.aox1d lines showed complete loss of AOX proteins and activity upon Pro treatment, yet full respiratory induction in response to Pro remained possible via the cytochrome pathway. However, aox1a.aox1d leaves displayed symptoms of elevated oxidative stress and suffered increased oxidative damage during Pro metabolism compared to the wild-type (WT) or the single mutants. During recovery from salt stress, when relatively high rates of Pro catabolism occur naturally, photosynthetic rates in aox1a.aox1d recovered slower than in the WT or the single aox lines, showing that both AOX1a and AOX1d are beneficial for cellular metabolism during Pro drawdown following osmotic stress. This work provides physiological evidence of a beneficial role for AOX1a but also the less studied AOX1d isoform in allowing safe catabolism of alternative respiratory substrates like Pro.
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Affiliation(s)
- Glenda Guek Khim Oh
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, University of Western Australia, Crawley WA 6009, Australia
| | - Brendan M O’Leary
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, University of Western Australia, Crawley WA 6009, Australia
- Saskatoon Research and Development Centre, Agriculture and Agri-food, Saskatoon, SK S7N 0X2, Canada
| | - Santiago Signorelli
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, University of Western Australia, Crawley WA 6009, Australia
- Laboratorio de Bioquímica, Departamento de Biología Vegetal, Facultad de Agronomía, Universidad de la República, Uruguay
| | - A Harvey Millar
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, University of Western Australia, Crawley WA 6009, Australia
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Challabathula D, Analin B, Mohanan A, Bakka K. Differential modulation of photosynthesis, ROS and antioxidant enzyme activities in stress-sensitive and -tolerant rice cultivars during salinity and drought upon restriction of COX and AOX pathways of mitochondrial oxidative electron transport. JOURNAL OF PLANT PHYSIOLOGY 2022; 268:153583. [PMID: 34871988 DOI: 10.1016/j.jplph.2021.153583] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 11/24/2021] [Accepted: 11/25/2021] [Indexed: 05/27/2023]
Abstract
Drought and salt stresses are two major abiotic stress factors that hamper crop growth and productivity. Three rice cultivars with different sensitivity and tolerance towards abiotic stress were used in the current study. While cultivar Aiswarya is salt- and drought-sensitive, cultivar Vyttila is salt-tolerant and cultivar Vaisakh is drought-tolerant. We compared the physiological and biochemical responses of these rice cultivars under salt and drought stress conditions after restricting their cytochrome oxidase (COX) and alternative oxidase (AOX) pathways using antimycin A and salicylhydroxamic acid treatment. Further, changes in their expression of AOX genes and corresponding protein levels were compared and analysed. The sensitive and tolerant rice cultivars subjected to drought and salt stress showed differential responses in physiological and biochemical traits. Whereas Aiswarya showed clear phenotypic differences, such as stunted growth, leaf curling, and loss of greening in leaf tissues, with increase in salt content and progressive drought stress, Vyttila and Vaisakh showed no remarkable changes. Moreover, the drought-tolerant cultivar rehydrated after 10 days of drought exposure, whereas the sensitive variety did not show any rehydration of leaf tissue. The leaves of the tolerant cultivars showed lower reactive oxygen species (ROS) production than that of the sensitive plants under drought and salt stress conditions because of the activation of a stronger antioxidant defence. Although, the restriction of COX and AOX pathways increased the susceptibility of sensitive cultivars, it affected the tolerant varieties moderately. Higher photosynthetic rates, an efficient antioxidant system comprising higher superoxide dismutase, ascorbate peroxidase, and catalase activity along with higher AOX1a gene expression levels during drought and salt stress were observed in tolerant cultivars. The results suggest that an efficient antioxidant system and increased transcription of the AOX1a gene along with higher AOX protein levels are important for tolerant rice cultivars to maintain higher photosynthesis rates, lower ROS, and stress tolerance. Restriction of COX and AOX pathways impact the photosynthesis, ROS, and antioxidant enzymes in both sensitive and tolerant cultivars. The restriction of COX and AOX pathways have a stronger impact on gas exchange and fluorescence parameters of the sensitive cultivar than on that of the tolerant cultivars owing to the higher photosynthetic rates in tolerant cultivars.
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Affiliation(s)
- Dinakar Challabathula
- Plant Molecular Stress Physiology Research Group, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu, Thiruvarur, 610 005, India.
| | - Benedict Analin
- Plant Molecular Stress Physiology Research Group, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu, Thiruvarur, 610 005, India
| | - Akhil Mohanan
- Plant Molecular Stress Physiology Research Group, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu, Thiruvarur, 610 005, India
| | - Kavya Bakka
- Department of Microbiology, School of Life Sciences, Central University of Tamil Nadu, Thiruvarur, 610 005, India
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Chadee A, Alber NA, Dahal K, Vanlerberghe GC. The Complementary Roles of Chloroplast Cyclic Electron Transport and Mitochondrial Alternative Oxidase to Ensure Photosynthetic Performance. FRONTIERS IN PLANT SCIENCE 2021; 12:748204. [PMID: 34650584 PMCID: PMC8505746 DOI: 10.3389/fpls.2021.748204] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 08/30/2021] [Indexed: 05/29/2023]
Abstract
Chloroplasts use light energy and a linear electron transport (LET) pathway for the coupled generation of NADPH and ATP. It is widely accepted that the production ratio of ATP to NADPH is usually less than required to fulfill the energetic needs of the chloroplast. Left uncorrected, this would quickly result in an over-reduction of the stromal pyridine nucleotide pool (i.e., high NADPH/NADP+ ratio) and under-energization of the stromal adenine nucleotide pool (i.e., low ATP/ADP ratio). These imbalances could cause metabolic bottlenecks, as well as increased generation of damaging reactive oxygen species. Chloroplast cyclic electron transport (CET) and the chloroplast malate valve could each act to prevent stromal over-reduction, albeit in distinct ways. CET avoids the NADPH production associated with LET, while the malate valve consumes the NADPH associated with LET. CET could operate by one of two different pathways, depending upon the chloroplast ATP demand. The NADH dehydrogenase-like pathway yields a higher ATP return per electron flux than the pathway involving PROTON GRADIENT REGULATION5 (PGR5) and PGR5-LIKE PHOTOSYNTHETIC PHENOTYPE1 (PGRL1). Similarly, the malate valve could couple with one of two different mitochondrial electron transport pathways, depending upon the cytosolic ATP demand. The cytochrome pathway yields a higher ATP return per electron flux than the alternative oxidase (AOX) pathway. In both Arabidopsis thaliana and Chlamydomonas reinhardtii, PGR5/PGRL1 pathway mutants have increased amounts of AOX, suggesting complementary roles for these two lesser-ATP yielding mechanisms of preventing stromal over-reduction. These two pathways may become most relevant under environmental stress conditions that lower the ATP demands for carbon fixation and carbohydrate export.
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Affiliation(s)
- Avesh Chadee
- Department of Biological Sciences, and Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, ON, Canada
| | - Nicole A. Alber
- Department of Biological Sciences, and Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, ON, Canada
| | - Keshav Dahal
- Fredericton Research and Development Centre, Agriculture and Agri-Food Canada, Fredericton, NB, Canada
| | - Greg C. Vanlerberghe
- Department of Biological Sciences, and Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, ON, Canada
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Garmash EV. Role of mitochondrial alternative oxidase in the regulation of cellular homeostasis during development of photosynthetic function in greening leaves. PLANT BIOLOGY (STUTTGART, GERMANY) 2021; 23:221-228. [PMID: 33190385 DOI: 10.1111/plb.13217] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 11/08/2020] [Indexed: 05/27/2023]
Abstract
Here, recent publications on the role of mitochondrial non-phosphorylating pathways (NPhPs) in the electron transport chain during the de-etiolation of wheat leaves are reviewed. Among NPhPs, the alternative oxidase (AOX) pathway is the most effective pathway in maintaining cellular redox and energy balance, especially under stress conditions, including light stress. AOX is considered to dissipate excess reductants produced in the chloroplasts, and thereby prevent photooxidation. However, when etiolated wheat plants were exposed to a physiologically relevant light level, AOX was rapidly induced and increased, although the etioplasts did not produce excess reductants and have their own strong photoprotective mechanisms. The present study provides further insights into the role of AOX in greening cells and highlights the importance of AOX in the integration of cellular signalling pathways.
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Affiliation(s)
- E V Garmash
- Institute of Biology, Komi Scientific Centre, Ural Branch, Russian Academy of Sciences, Syktyvkar, 167982, Russian Federation
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Popov VN, Syromyatnikov MY, Fernie AR, Chakraborty S, Gupta KJ, Igamberdiev AU. The uncoupling of respiration in plant mitochondria: keeping reactive oxygen and nitrogen species under control. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:793-807. [PMID: 33245770 DOI: 10.1093/jxb/eraa510] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/26/2020] [Indexed: 06/11/2023]
Abstract
Plant mitochondrial respiration involves the operation of various alternative pathways. These pathways participate, both directly and indirectly, in the maintenance of mitochondrial functions though they do not contribute to energy production, being uncoupled from the generation of an electrochemical gradient across the mitochondrial membrane and thus from ATP production. Recent findings suggest that uncoupled respiration is involved in reactive oxygen species (ROS) and nitric oxide (NO) scavenging, regulation, and homeostasis. Here we discuss specific roles and possible functions of uncoupled mitochondrial respiration in ROS and NO metabolism. The mechanisms of expression and regulation of the NDA-, NDB- and NDC-type non-coupled NADH and NADPH dehydrogenases, the alternative oxidase (AOX), and the uncoupling protein (UCP) are examined in relation to their involvement in the establishment of the stable far-from-equilibrium state of plant metabolism. The role of uncoupled respiration in controlling the levels of ROS and NO as well as inducing signaling events is considered. Secondary functions of uncoupled respiration include its role in protection from stress factors and roles in biosynthesis and catabolism. It is concluded that uncoupled mitochondrial respiration plays an important role in providing rapid adaptation of plants to changing environmental factors via regulation of ROS and NO.
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Affiliation(s)
- Vasily N Popov
- Department of Genetics, Cytology and Bioengineering, Voronezh State University, Voronezh, Russia
- Voronezh State University of Engineering Technologies, Voronezh, Russia
| | - Mikhail Y Syromyatnikov
- Department of Genetics, Cytology and Bioengineering, Voronezh State University, Voronezh, Russia
- Voronezh State University of Engineering Technologies, Voronezh, Russia
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Subhra Chakraborty
- National Institute for Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| | | | - Abir U Igamberdiev
- Department of Biology, Memorial University of Newfoundland, St John's, NL, Canada
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12
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Hewitt S, Dhingra A. Beyond Ethylene: New Insights Regarding the Role of Alternative Oxidase in the Respiratory Climacteric. FRONTIERS IN PLANT SCIENCE 2020; 11:543958. [PMID: 33193478 PMCID: PMC7652990 DOI: 10.3389/fpls.2020.543958] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 09/24/2020] [Indexed: 06/11/2023]
Abstract
Climacteric fruits are characterized by a dramatic increase in autocatalytic ethylene production that is accompanied by a spike in respiration at the onset of ripening. The change in the mode of ethylene production from autoinhibitory to autostimulatory is known as the System 1 (S1) to System 2 (S2) transition. Existing physiological models explain the basic and overarching genetic, hormonal, and transcriptional regulatory mechanisms governing the S1 to S2 transition of climacteric fruit. However, the links between ethylene and respiration, the two main factors that characterize the respiratory climacteric, have not been examined in detail at the molecular level. Results of recent studies indicate that the alternative oxidase (AOX) respiratory pathway may play an essential role in mediating cross-talk between ethylene response, carbon metabolism, ATP production, and ROS signaling during climacteric ripening. New genomic, metabolic, and epigenetic information sheds light on the interconnectedness of ripening metabolic pathways, necessitating an expansion of the current, ethylene-centric physiological models. Understanding points at which ripening responses can be manipulated may reveal key, species- and cultivar-specific targets for regulation of ripening, enabling superior strategies for reducing postharvest wastage.
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Affiliation(s)
- Seanna Hewitt
- Molecular Plant Sciences Program, Washington State University, Pullman, WA, United States
- Department of Horticulture, Washington State University, Pullman, WA, United States
| | - Amit Dhingra
- Molecular Plant Sciences Program, Washington State University, Pullman, WA, United States
- Department of Horticulture, Washington State University, Pullman, WA, United States
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13
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Sweetman C, Miller TK, Booth NJ, Shavrukov Y, Jenkins CL, Soole KL, Day DA. Identification of Alternative Mitochondrial Electron Transport Pathway Components in Chickpea Indicates a Differential Response to Salinity Stress between Cultivars. Int J Mol Sci 2020; 21:E3844. [PMID: 32481694 PMCID: PMC7312301 DOI: 10.3390/ijms21113844] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 11/16/2022] Open
Abstract
All plants contain an alternative electron transport pathway (AP) in their mitochondria, consisting of the alternative oxidase (AOX) and type 2 NAD(P)H dehydrogenase (ND) families, that are thought to play a role in controlling oxidative stress responses at the cellular level. These alternative electron transport components have been extensively studied in plants like Arabidopsis and stress inducible isoforms identified, but we know very little about them in the important crop plant chickpea. Here we identify AP components in chickpea (Cicer arietinum) and explore their response to stress at the transcript level. Based on sequence similarity with the functionally characterized proteins of Arabidopsis thaliana, five putative internal (matrix)-facing NAD(P)H dehydrogenases (CaNDA1-4 and CaNDC1) and four putative external (inter-membrane space)-facing NAD(P)H dehydrogenases (CaNDB1-4) were identified in chickpea. The corresponding activities were demonstrated for the first time in purified mitochondria of chickpea leaves and roots. Oxidation of matrix NADH generated from malate or glycine in the presence of the Complex I inhibitor rotenone was high compared to other plant species, as was oxidation of exogenous NAD(P)H. In leaf mitochondria, external NADH oxidation was stimulated by exogenous calcium and external NADPH oxidation was essentially calcium dependent. However, in roots these activities were low and largely calcium independent. A salinity experiment with six chickpea cultivars was used to identify salt-responsive alternative oxidase and NAD(P)H dehydrogenase gene transcripts in leaves from a three-point time series. An analysis of the Na:K ratio and Na content separated these cultivars into high and low Na accumulators. In the high Na accumulators, there was a significant up-regulation of CaAOX1, CaNDB2, CaNDB4, CaNDA3 and CaNDC1 in leaf tissue under long term stress, suggesting the formation of a stress-modified form of the mitochondrial electron transport chain (mETC) in leaves of these cultivars. In particular, stress-induced expression of the CaNDB2 gene showed a striking positive correlation with that of CaAOX1 across all genotypes and time points. The coordinated salinity-induced up-regulation of CaAOX1 and CaNDB2 suggests that the mitochondrial alternative pathway of respiration is an important facet of the stress response in chickpea, in high Na accumulators in particular, despite high capacities for both of these activities in leaf mitochondria of non-stressed chickpeas.
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Affiliation(s)
- Crystal Sweetman
- College of Science & Engineering, Flinders University, GPO Box 5100, Adelaide SA 5001, Australia; (T.K.M.); (N.J.B.); (Y.S.); (C.L.D.J.); (K.L.S.); (D.A.D.)
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14
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Yamada S, Ozaki H, Noguchi K. The Mitochondrial Respiratory Chain Maintains the Photosynthetic Electron Flow in Arabidopsis thaliana Leaves under High-Light Stress. PLANT & CELL PHYSIOLOGY 2020; 61:283-295. [PMID: 31603217 DOI: 10.1093/pcp/pcz193] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 10/07/2019] [Indexed: 05/02/2023]
Abstract
The plant respiratory chain includes the ATP-coupling cytochrome pathway (CP) and ATP-uncoupling alternative oxidase (AOX). Under high-light (HL) conditions, plants experience photoinhibition, leading to a damaged photosystem II (PSII). The respiratory chain is considered to affect PSII maintenance and photosynthetic electron transport under HL conditions. However, the underlying details remain unclear. In this study, we investigated the respiratory chain functions related to PSII maintenance and photosynthetic electron transport in plants exposed to HL stress. We measured the HL-induced decrease in the maximum quantum yield of PSII in the leaves of wild-type and AOX1a-knockout (aox1a) Arabidopsis thaliana plants in which CP was partially inhibited by a complex-III inhibitor. We also calculated PSII photodamage and repair rate constants. Both rate constants changed when CP was partially inhibited in aox1a plants, suggesting that the respiratory chain is related to both processes. Before HL stress, photosynthetic linear electron flow (LEF) decreased when CP was partially inhibited. After HL stress, aox1a in the presence of the CP inhibitor showed significantly decreased rates of LEF. The electron flow downstream from PSII and on the donor side of photosystem I may have been suppressed. The function of respiratory chain is required to maintain the optimal LEF as well as PSII maintenance especially under the HL stress.
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Affiliation(s)
- Shoya Yamada
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392 Japan
| | - Hiroshi Ozaki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392 Japan
| | - Ko Noguchi
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392 Japan
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15
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Liu C, Li LL, Li GZ, Hao L. Ethylene insensitive mutation improves Arabidopsis plant tolerance to NO 2 exposure. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 189:110043. [PMID: 31812821 DOI: 10.1016/j.ecoenv.2019.110043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/25/2019] [Accepted: 12/01/2019] [Indexed: 06/10/2023]
Abstract
Ethylene signaling was addressed, for the first time, in plant responses to nitrogen dioxide (NO2) by comparatively analyzing the performance of Arabidopsis ethylene insensitive 2 (ein2-1) with wild-type (WT) plants. Following NO2 fumigation, severe leaf wilting and chlorosis occurred in WT plants, but much less symptoms were observed in ein2-1. The activities of superoxide dismutase (SOD), peroxidase (PRX) and catalase (CAT) were 39%, 92%, and 11% higher, respectively, in ein2-1 than in WT following NO2 exposure. Although glutathione contents and the ratio of its reduced form (GSH) to oxidized form (GSSG) were decreased by NO2, an obviously alleviated degree was detected in ein2-1 relative to WT. Correspondingly, the contents of hydrogen peroxide (H2O2) and malondialdehyde (MDA), and electrolyte leakage were 25%, 24%, and 29% lower, respectively, in ein2-1 than in WT. The difference of oxidative stress between two tested genotypes was also revealed by the leaf staining regarding the production and distribution of H2O2, superoxide anion (O2˙-), and cell death. The genes involved in antioxidation or oxidation-reduction processes mostly presented a stronger expression in ein2-1 than in WT under NO2 stress. The photosynthesis-related parameters including chlorophyll and soluble sugar contents, net photosynthetic rate (Pn), and ribulose bisphosphate carboxylase/oxygenase (Rubisco) activity and gene expression, and chlorophyll fluorescence parameters were affected, generally, to a lesser degree in ein2-1 than in WT following NO2 fumigation. The enzymatic activities and gene expressions of invertases mostly displayed a higher level in ein2-1 relative to WT following NO2 fumigation. For example, the activities of cytoplasmic, cell wall and vacuolar invertases were 76%, 26%, and 26% higher, respectively, in ein2-1 than in WT. Together, these data suggest that ethylene signal insensitivity efficiently improves plant tolerance to NO2 exposure, and the possible mechanisms might be correlated with leaf antioxidative defense, photosynthesis-related processes, and sucrose metabolisms.
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Affiliation(s)
- Chuan Liu
- College of Life Science, Shenyang Normal University, Shenyang, 110034, China
| | - Lin-Lin Li
- College of Environment and Resource, Dalian Nationalities University, Dalian, 116605, China
| | - Guang-Zhe Li
- College of Life Science, Shenyang Normal University, Shenyang, 110034, China
| | - Lin Hao
- College of Life Science, Shenyang Normal University, Shenyang, 110034, China.
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Assessment of Subcellular ROS and NO Metabolism in Higher Plants: Multifunctional Signaling Molecules. Antioxidants (Basel) 2019; 8:antiox8120641. [PMID: 31842380 PMCID: PMC6943533 DOI: 10.3390/antiox8120641] [Citation(s) in RCA: 198] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/01/2019] [Accepted: 12/06/2019] [Indexed: 12/22/2022] Open
Abstract
Reactive oxygen species (ROS) and nitric oxide (NO) are produced in all aerobic life forms under both physiological and adverse conditions. Unregulated ROS/NO generation causes nitro-oxidative damage, which has a detrimental impact on the function of essential macromolecules. ROS/NO production is also involved in signaling processes as secondary messengers in plant cells under physiological conditions. ROS/NO generation takes place in different subcellular compartments including chloroplasts, mitochondria, peroxisomes, vacuoles, and a diverse range of plant membranes. This compartmentalization has been identified as an additional cellular strategy for regulating these molecules. This assessment of subcellular ROS/NO metabolisms includes the following processes: ROS/NO generation in different plant cell sites; ROS interactions with other signaling molecules, such as mitogen-activated protein kinases (MAPKs), phosphatase, calcium (Ca2+), and activator proteins; redox-sensitive genes regulated by the iron-responsive element/iron regulatory protein (IRE-IRP) system and iron regulatory transporter 1(IRT1); and ROS/NO crosstalk during signal transduction. All these processes highlight the complex relationship between ROS and NO metabolism which needs to be evaluated from a broad perspective.
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