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Barsottini MRO, Copsey A, Young L, Baroni RM, Cordeiro AT, Pereira GAG, Moore AL. Biochemical characterization and inhibition of the alternative oxidase enzyme from the fungal phytopathogen Moniliophthora perniciosa. Commun Biol 2020; 3:263. [PMID: 32451394 PMCID: PMC7248098 DOI: 10.1038/s42003-020-0981-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 04/30/2020] [Indexed: 01/27/2023] Open
Abstract
Moniliophthora perniciosa is a fungal pathogen and causal agent of the witches' broom disease of cocoa, a threat to the chocolate industry and to the economic and social security in cocoa-planting countries. The membrane-bound enzyme alternative oxidase (MpAOX) is crucial for pathogen survival; however a lack of information on the biochemical properties of MpAOX hinders the development of novel fungicides. In this study, we purified and characterised recombinant MpAOX in dose-response assays with activators and inhibitors, followed by a kinetic characterization both in an aqueous environment and in physiologically-relevant proteoliposomes. We present structure-activity relationships of AOX inhibitors such as colletochlorin B and analogues which, aided by an MpAOX structural model, indicates key residues for protein-inhibitor interaction. We also discuss the importance of the correct hydrophobic environment for MpAOX enzymatic activity. We envisage that such results will guide the future development of AOX-targeting antifungal agents against M. perniciosa, an important outcome for the chocolate industry.
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Affiliation(s)
- Mario R O Barsottini
- Genomics and bioEnergy Laboratory, Institute of Biology, University of Campinas, Campinas, Brazil.,Biochemistry & Biomedicine, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK
| | - Alice Copsey
- Biochemistry & Biomedicine, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK
| | - Luke Young
- Biochemistry & Biomedicine, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK
| | - Renata M Baroni
- Genomics and bioEnergy Laboratory, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Artur T Cordeiro
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Gonçalo A G Pereira
- Genomics and bioEnergy Laboratory, Institute of Biology, University of Campinas, Campinas, Brazil.
| | - Anthony L Moore
- Biochemistry & Biomedicine, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK.
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Kerbler SM, Taylor NL, Millar AH. Cold sensitivity of mitochondrial ATP synthase restricts oxidative phosphorylation in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2019; 221:1776-1788. [PMID: 30281799 DOI: 10.1111/nph.15509] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 09/20/2018] [Indexed: 05/03/2023]
Abstract
The combined action of the electron transport chain (ETC) and ATP synthase is essential in determining energy efficiency in plants, and so is important for cellular biosynthesis, growth and development. Owing to the sessile nature of plants, mitochondria must operate over a wide temperature range in the environment, necessitating a broad temperature tolerance of their biochemical reactions. We investigated the temperature response of mitochondrial respiratory processes in isolated mitochondria and intact plants of Arabidopsis thaliana and considered the effect of instantaneous responses to temperature and acclimation responses to low temperatures. We show that at 4°C the plant mitochondrial ATP synthase is differentially inhibited compared with other elements of the respiratory pathway, leading to decreased ADP : oxygen ratios and a limitation to the rate of ATP synthesis. This effect persists in vivo and cannot be overcome by cold-temperature acclimation of plants. This mechanism adds a new element to the respiratory acclimation model and provides a direct means of temperature perception by plant mitochondria. This also provides an alternative explanation for non-phosphorylating ETC bypass mechanisms, like the alternative oxidase to maintain respiratory rates, albeit at lower ATP synthesis efficiency, in response to the sensitivity of ATP synthase to the prevailing temperature.
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Affiliation(s)
- Sandra M Kerbler
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Nicolas L Taylor
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley, WA, 6009, Australia
- The Institute of Agriculture, The University of Western Australia, Crawley, WA, 6009, Australia
| | - A Harvey Millar
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley, WA, 6009, Australia
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Wanniarachchi VR, Dametto L, Sweetman C, Shavrukov Y, Day DA, Jenkins CLD, Soole KL. Alternative Respiratory Pathway Component Genes (AOX and ND) in Rice and Barley and Their Response to Stress. Int J Mol Sci 2018; 19:E915. [PMID: 29558397 PMCID: PMC5877776 DOI: 10.3390/ijms19030915] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 03/15/2018] [Accepted: 03/16/2018] [Indexed: 11/24/2022] Open
Abstract
Plants have a non-energy conserving bypass of the classical mitochondrial cytochrome c pathway, known as the alternative respiratory pathway (AP). This involves type II NAD(P)H dehydrogenases (NDs) on both sides of the mitochondrial inner membrane, ubiquinone, and the alternative oxidase (AOX). The AP components have been widely characterised from Arabidopsis, but little is known for monocot species. We have identified all the genes encoding components of the AP in rice and barley and found the key genes which respond to oxidative stress conditions. In both species, AOX is encoded by four genes; in rice OsAOX1a, 1c, 1d and 1e representing four clades, and in barley, HvAOX1a, 1c, 1d1 and 1d2, but no 1e. All three subfamilies of plant ND genes, NDA, NDB and NDC are present in both rice and barley, but there are fewer NDB genes compared to Arabidopsis. Cyanide treatment of both species, along with salt treatment of rice and drought treatment of barley led to enhanced expression of various AP components; there was a high level of co-expression of AOX1a and AOX1d, along with NDB3 during the stress treatments, reminiscent of the co-expression that has been well characterised in Arabidopsis for AtAOX1a and AtNDB2.
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Affiliation(s)
- Vajira R Wanniarachchi
- College of Science and Engineering, Flinders University of South Australia, GPO Box 5100, Adelaide, SA 5001, Australia.
| | - Lettee Dametto
- College of Science and Engineering, Flinders University of South Australia, GPO Box 5100, Adelaide, SA 5001, Australia.
| | - Crystal Sweetman
- College of Science and Engineering, Flinders University of South Australia, GPO Box 5100, Adelaide, SA 5001, Australia.
| | - Yuri Shavrukov
- College of Science and Engineering, Flinders University of South Australia, GPO Box 5100, Adelaide, SA 5001, Australia.
| | - David A Day
- College of Science and Engineering, Flinders University of South Australia, GPO Box 5100, Adelaide, SA 5001, Australia.
| | - Colin L D Jenkins
- College of Science and Engineering, Flinders University of South Australia, GPO Box 5100, Adelaide, SA 5001, Australia.
| | - Kathleen L Soole
- College of Science and Engineering, Flinders University of South Australia, GPO Box 5100, Adelaide, SA 5001, Australia.
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Erdal S, Genisel M, Turk H, Dumlupinar R, Demir Y. Modulation of alternative oxidase to enhance tolerance against cold stress of chickpea by chemical treatments. JOURNAL OF PLANT PHYSIOLOGY 2015; 175:95-101. [PMID: 25543861 DOI: 10.1016/j.jplph.2014.10.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 09/17/2014] [Accepted: 10/10/2014] [Indexed: 05/04/2023]
Abstract
The alternative oxidase (AOX) is the enzyme responsible for the alternative respiratory pathway. This experiment was conducted to examine the influence on cold tolerance ability of chickpea (Cicer aurentium cv. Müfitbey) seedlings of AOX activator (pyruvate), AOX inhibitor (salicylhydroxamic acid (SHAM)) and an inhibitor of the cytochrome pathway of respiration (antimycin A) treatments. 5mM pyruvate, 2μM antimycin A and 4mM SHAM solutions were exogenously applied to thirteen-day-old chickpea leaves and then the seedlings were transferred to a different plant growth chamber arranged to 10/5°C (day/night) for 48h. Cold stress markedly increased the activities of antioxidant enzymes compared to controls. Pyruvate and antimycin A significantly increased the cold-induced increase in antioxidant activity but SHAM decreased it. Cold-induced increases in superoxide anion, hydrogen peroxide, and lipid peroxidation levels were significantly reduced by pyruvate and antimycin A, but increased by SHAM treatment. Pyruvate and antimycin A application increased both the activity and protein expression of AOX in comparison to cold stress alone. However, SHAM significantly decreased activity of AOX but did not affect its expression. Total cellular respiration values (TCRV) supported the changes in activity and expression of AOX. While TCRV were increased by cold and pyruvate, they were significantly reduced by SHAM and especially antimycin A. These results indicate that pyruvate and antimycin A applications were effective in reducing oxidative stress by activating the alternative respiratory pathway as well as antioxidant activity. Furthermore, direct activation of AOX, rather than inhibition of the cytochrome pathway, was the most effective way to mitigate cold stress.
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Affiliation(s)
- Serkan Erdal
- Department of Biology, Science Faculty, Ataturk University, Erzurum, Turkey.
| | - Mucip Genisel
- Organic Agriculture Program, Vocational High School, Agri Ibrahim Cecen University, 04100 Agri, Turkey
| | - Hulya Turk
- Department of Biology, Science Faculty, Ataturk University, Erzurum, Turkey
| | - Rahmi Dumlupinar
- Department of Biology, Science Faculty, Ataturk University, Erzurum, Turkey
| | - Yavuz Demir
- Department of Biology, K. K. Education Faculty, Ataturk University, Erzurum, Turkey
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Kühn K, Yin G, Duncan O, Law SR, Kubiszewski-Jakubiak S, Kaur P, Meyer E, Wang Y, Small CCDF, Giraud E, Narsai R, Whelan J. Decreasing electron flux through the cytochrome and/or alternative respiratory pathways triggers common and distinct cellular responses dependent on growth conditions. PLANT PHYSIOLOGY 2015; 167:228-50. [PMID: 25378695 PMCID: PMC4281006 DOI: 10.1104/pp.114.249946] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 10/29/2014] [Indexed: 05/18/2023]
Abstract
Diverse signaling pathways are activated by perturbation of mitochondrial function under different growth conditions.Mitochondria have emerged as an important organelle for sensing and coping with stress in addition to being the sites of important metabolic pathways. Here, responses to moderate light and drought stress were examined in different Arabidopsis (Arabidopsis thaliana) mutant plants lacking a functional alternative oxidase (alternative oxidase1a [aox1a]), those with reduced cytochrome electron transport chain capacity (T3/T7 bacteriophage-type RNA polymerase, mitochondrial, and plastidial [rpoTmp]), and double mutants impaired in both pathways (aox1a:rpoTmp). Under conditions considered optimal for growth, transcriptomes of aox1a and rpoTmp were distinct. Under adverse growth conditions, however, transcriptome changes in aox1a and rpoTmp displayed a highly significant overlap and were indicative of a common mitochondrial stress response and down-regulation of photosynthesis. This suggests that the role of mitochondria to support photosynthesis is provided through either the alternative pathway or the cytochrome pathway, and when either pathway is inhibited, such as under environmental stress, a common, dramatic, and succinct mitochondrial signal is activated to alter energy metabolism in both organelles. aox1a:rpoTmp double mutants grown under optimal conditions showed dramatic reductions in biomass production compared with aox1a and rpoTmp and a transcriptome that was distinct from aox1a or rpoTmp. Transcript data indicating activation of mitochondrial biogenesis in aox1a:rpoTmp were supported by a proteomic analysis of over 200 proteins. Under optimal conditions, aox1a:rpoTmp plants seemed to switch on many of the typical mitochondrial stress regulators. Under adverse conditions, aox1a:rpoTmp turned off these responses and displayed a biotic stress response. Taken together, these results highlight the diverse signaling pathways activated by the perturbation of mitochondrial function under different growth conditions.
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Affiliation(s)
- Kristina Kühn
- Molekulare Zellbiologie der Pflanzen, Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany (K.K.);Australian Research Council Centre of Excellence in Plant Energy Biology (G.Y., O.D., S.K.-J., C.C.d.F.S.) andCentre for Plant Genetics and Breeding (P.K.), University of Western Australia, Crawley, Western Australia 6009, Australia;National Genebank, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China (G.Y.);Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, Victoria 3083, Australia (S.R.L., Y.W., R.N., J.W.);Department of Organelle Biology and Biotechnology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (E.M.); andIllumina, Inc., Scoresby, Victoria 3179, Australia (E.G.)
| | - Guangkun Yin
- Molekulare Zellbiologie der Pflanzen, Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany (K.K.);Australian Research Council Centre of Excellence in Plant Energy Biology (G.Y., O.D., S.K.-J., C.C.d.F.S.) andCentre for Plant Genetics and Breeding (P.K.), University of Western Australia, Crawley, Western Australia 6009, Australia;National Genebank, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China (G.Y.);Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, Victoria 3083, Australia (S.R.L., Y.W., R.N., J.W.);Department of Organelle Biology and Biotechnology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (E.M.); andIllumina, Inc., Scoresby, Victoria 3179, Australia (E.G.)
| | - Owen Duncan
- Molekulare Zellbiologie der Pflanzen, Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany (K.K.);Australian Research Council Centre of Excellence in Plant Energy Biology (G.Y., O.D., S.K.-J., C.C.d.F.S.) andCentre for Plant Genetics and Breeding (P.K.), University of Western Australia, Crawley, Western Australia 6009, Australia;National Genebank, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China (G.Y.);Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, Victoria 3083, Australia (S.R.L., Y.W., R.N., J.W.);Department of Organelle Biology and Biotechnology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (E.M.); andIllumina, Inc., Scoresby, Victoria 3179, Australia (E.G.)
| | - Simon R Law
- Molekulare Zellbiologie der Pflanzen, Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany (K.K.);Australian Research Council Centre of Excellence in Plant Energy Biology (G.Y., O.D., S.K.-J., C.C.d.F.S.) andCentre for Plant Genetics and Breeding (P.K.), University of Western Australia, Crawley, Western Australia 6009, Australia;National Genebank, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China (G.Y.);Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, Victoria 3083, Australia (S.R.L., Y.W., R.N., J.W.);Department of Organelle Biology and Biotechnology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (E.M.); andIllumina, Inc., Scoresby, Victoria 3179, Australia (E.G.)
| | - Szymon Kubiszewski-Jakubiak
- Molekulare Zellbiologie der Pflanzen, Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany (K.K.);Australian Research Council Centre of Excellence in Plant Energy Biology (G.Y., O.D., S.K.-J., C.C.d.F.S.) andCentre for Plant Genetics and Breeding (P.K.), University of Western Australia, Crawley, Western Australia 6009, Australia;National Genebank, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China (G.Y.);Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, Victoria 3083, Australia (S.R.L., Y.W., R.N., J.W.);Department of Organelle Biology and Biotechnology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (E.M.); andIllumina, Inc., Scoresby, Victoria 3179, Australia (E.G.)
| | - Parwinder Kaur
- Molekulare Zellbiologie der Pflanzen, Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany (K.K.);Australian Research Council Centre of Excellence in Plant Energy Biology (G.Y., O.D., S.K.-J., C.C.d.F.S.) andCentre for Plant Genetics and Breeding (P.K.), University of Western Australia, Crawley, Western Australia 6009, Australia;National Genebank, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China (G.Y.);Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, Victoria 3083, Australia (S.R.L., Y.W., R.N., J.W.);Department of Organelle Biology and Biotechnology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (E.M.); andIllumina, Inc., Scoresby, Victoria 3179, Australia (E.G.)
| | - Etienne Meyer
- Molekulare Zellbiologie der Pflanzen, Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany (K.K.);Australian Research Council Centre of Excellence in Plant Energy Biology (G.Y., O.D., S.K.-J., C.C.d.F.S.) andCentre for Plant Genetics and Breeding (P.K.), University of Western Australia, Crawley, Western Australia 6009, Australia;National Genebank, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China (G.Y.);Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, Victoria 3083, Australia (S.R.L., Y.W., R.N., J.W.);Department of Organelle Biology and Biotechnology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (E.M.); andIllumina, Inc., Scoresby, Victoria 3179, Australia (E.G.)
| | - Yan Wang
- Molekulare Zellbiologie der Pflanzen, Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany (K.K.);Australian Research Council Centre of Excellence in Plant Energy Biology (G.Y., O.D., S.K.-J., C.C.d.F.S.) andCentre for Plant Genetics and Breeding (P.K.), University of Western Australia, Crawley, Western Australia 6009, Australia;National Genebank, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China (G.Y.);Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, Victoria 3083, Australia (S.R.L., Y.W., R.N., J.W.);Department of Organelle Biology and Biotechnology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (E.M.); andIllumina, Inc., Scoresby, Victoria 3179, Australia (E.G.)
| | - Catherine Colas des Francs Small
- Molekulare Zellbiologie der Pflanzen, Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany (K.K.);Australian Research Council Centre of Excellence in Plant Energy Biology (G.Y., O.D., S.K.-J., C.C.d.F.S.) andCentre for Plant Genetics and Breeding (P.K.), University of Western Australia, Crawley, Western Australia 6009, Australia;National Genebank, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China (G.Y.);Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, Victoria 3083, Australia (S.R.L., Y.W., R.N., J.W.);Department of Organelle Biology and Biotechnology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (E.M.); andIllumina, Inc., Scoresby, Victoria 3179, Australia (E.G.)
| | - Estelle Giraud
- Molekulare Zellbiologie der Pflanzen, Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany (K.K.);Australian Research Council Centre of Excellence in Plant Energy Biology (G.Y., O.D., S.K.-J., C.C.d.F.S.) andCentre for Plant Genetics and Breeding (P.K.), University of Western Australia, Crawley, Western Australia 6009, Australia;National Genebank, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China (G.Y.);Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, Victoria 3083, Australia (S.R.L., Y.W., R.N., J.W.);Department of Organelle Biology and Biotechnology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (E.M.); andIllumina, Inc., Scoresby, Victoria 3179, Australia (E.G.)
| | - Reena Narsai
- Molekulare Zellbiologie der Pflanzen, Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany (K.K.);Australian Research Council Centre of Excellence in Plant Energy Biology (G.Y., O.D., S.K.-J., C.C.d.F.S.) andCentre for Plant Genetics and Breeding (P.K.), University of Western Australia, Crawley, Western Australia 6009, Australia;National Genebank, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China (G.Y.);Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, Victoria 3083, Australia (S.R.L., Y.W., R.N., J.W.);Department of Organelle Biology and Biotechnology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (E.M.); andIllumina, Inc., Scoresby, Victoria 3179, Australia (E.G.)
| | - James Whelan
- Molekulare Zellbiologie der Pflanzen, Institut für Biologie, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany (K.K.);Australian Research Council Centre of Excellence in Plant Energy Biology (G.Y., O.D., S.K.-J., C.C.d.F.S.) andCentre for Plant Genetics and Breeding (P.K.), University of Western Australia, Crawley, Western Australia 6009, Australia;National Genebank, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China (G.Y.);Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, Victoria 3083, Australia (S.R.L., Y.W., R.N., J.W.);Department of Organelle Biology and Biotechnology, Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (E.M.); andIllumina, Inc., Scoresby, Victoria 3179, Australia (E.G.)
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Liu J, Li Z, Wang Y, Xing D. Overexpression of ALTERNATIVE OXIDASE1a alleviates mitochondria-dependent programmed cell death induced by aluminium phytotoxicity in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:4465-78. [PMID: 24863436 DOI: 10.1093/jxb/eru222] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Alternative oxidase (AOX) is a terminal oxidase found in all plants, and functions to maintain the electron flux and reduce the production of reactive oxygen species (ROS). Our previous study demonstrated that aluminium (Al) treatment could induce increased expression of the AOX1a gene, but the mechanism of how AOX1a participates in the regulation of Al-induced programmed cell death (PCD) is still not clear. To investigate the possible mechanism, mitochondrial ROS production and the behaviour of mitochondria, as well as caspase-3-like activation were monitored under Al treatment in wild-type (WT), AOX1a-lacking (aox1a), and AOX1a-overexpressing (AOX1a-OE) Arabidopsis. Our results showed that Al treatment increased the expression of AOX1a at both the transcriptional and translational levels. Overexpression of AOX1a reduced mitochondrial ROS production by maintaining the mitochondrial electron flux, and alleviated subsequent mitochondrial dysfunction and caspase-3-like activation in Al-induced PCD. Moreover, it was found that a change in AOX1a level could influence the expression levels of downstream functional genes that play protective roles in Al-induced PCD. Experiments using mutants and inhibitors demonstrated that superoxide anion (O2 (-)) derived from mitochondria was involved in Al-induced upregulation of AOX1a gene expression. Taken together, these results indicated that overexpression of AOX1a alleviated Al-induced PCD by maintaining mitochondrial function and promoting the expression of protective functional genes, providing new insights into the signalling cascades that modulate the Al phytotoxicity mechanism.
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Affiliation(s)
- Jian Liu
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, PR China
| | - Zhe Li
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, PR China
| | - Yongqiang Wang
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, PR China
| | - Da Xing
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, PR China
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Florez-Sarasa I, Lambers H, Wang X, Finnegan PM, Ribas-Carbo M. The alternative respiratory pathway mediates carboxylate synthesis in white lupin cluster roots under phosphorus deprivation. PLANT, CELL & ENVIRONMENT 2014; 37:922-928. [PMID: 24118034 DOI: 10.1111/pce.12208] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/04/2013] [Accepted: 09/09/2013] [Indexed: 06/02/2023]
Abstract
Plant adaptations associated with a high efficiency of phosphorus (P) acquisition can be used to increase productivity and sustainability in a world with a growing population and decreasing rock phosphate reserves. White lupin (Lupinus albus) produces cluster roots that release carboxylates to efficiently mobilize P from P-sorbing soils. It has been hypothesized that an increase in the activity of the alternative oxidase (AOX) would allow for the mitochondrial oxidation of NAD(P)H produced during citrate synthesis in cluster roots at a developmental stage when there is a low demand for ATP. We used the oxygen-isotope fractionation technique to study the in vivo respiratory activities of the cytochrome oxidase pathway (COP) and the alternative oxidase pathway (AOP) in different root sections of white lupins grown hydroponically with and without P. In parallel, AOX protein levels and internal carboxylate concentrations were determined in cluster and non-cluster roots. Higher in vivo AOP activity was measured in cluster roots when malate and citrate concentrations were also high, thus confirming our hypothesis. AOX protein levels were not always correlated with in vivo AOP activity, suggesting post-translational regulation of AOX.
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Affiliation(s)
- Igor Florez-Sarasa
- Grup de Recerca en Biologia de les Plantes en Condicions Mediterranies, Departament de Biologia, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122, Palma de Mallorca, Spain
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Chai TT, Simmonds D, Day DA, Colmer TD, Finnegan PM. Photosynthetic performance and fertility are repressed in GmAOX2b antisense soybean. PLANT PHYSIOLOGY 2010; 152:1638-49. [PMID: 20097793 PMCID: PMC2832272 DOI: 10.1104/pp.109.149294] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Accepted: 01/19/2010] [Indexed: 05/07/2023]
Abstract
The alternative oxidase (AOX) is a cyanide-resistant oxidase that provides an alternative outlet for electrons from the respiratory electron transport chain embedded in the inner membrane of plant mitochondria. Examination of soybean (Glycine max) plants carrying a GmAOX2b antisense gene showed AOX to have a central role in reproductive development and fecundity. In three independently transformed antisense lines, seed set was reduced by 16% to 43%, whereas ovule abortion increased by 1.2- to 1.7-fold when compared with nontransgenic transformation control plants. Reduced fecundity was associated with reductions in whole leaf cyanide-resistant, salicylhydroxamic acid-sensitive respiration and net photosynthesis, but there was no change in total respiration in the dark. The frequency of potential fertilization events was reduced by at least one-third in the antisense plants as a likely consequence of prefertilization defects. Pistils of the antisense plants contained a higher proportion of immature-sized, nonfertile embryo sacs compared with nontransgenic control plants. Increased rates of pollen abortion in vivo and reduced rates of pollen germination in vitro suggested that the antisense gene compromised pollen development and function. Reciprocal crosses between antisense and nontransgenic plants revealed that pollen produced by antisense plants was less active in fertilization. Taken together, the results presented here indicate that AOX expression has an important role in determining normal gametophyte development and function.
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Affiliation(s)
| | | | | | | | - Patrick M. Finnegan
- School of Plant Biology and Institute of Agriculture, Faculty of Natural and Agricultural Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia (T.-T.C., T.D.C., P.M.F.); Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada K1A 0C6 (D.S.); and Australian Research Council Centre of Excellence in Plant Energy Biology, School of Biological Sciences, Flinders University, Adelaide, South Australia 5001, Australia (D.A.D.)
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9
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McDonald AE. Alternative oxidase: what information can protein sequence comparisons give us? PHYSIOLOGIA PLANTARUM 2009; 137:328-341. [PMID: 19493309 DOI: 10.1111/j.1399-3054.2009.01242.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The finding that alternative oxidase (AOX) is present in most kingdoms of life has resulted in a large number of AOX sequences that are available for analyses. Multiple sequence alignments of AOX proteins from evolutionarily divergent organisms represent a valuable tool and can be used to identify amino acids and domains that may play a role in catalysis, membrane association and post-translational regulation, especially when these data are coupled with the structural model for the enzyme. I validate the use of this approach by demonstrating that it detects the conserved glutamate and histidine residues in AOX that initially led to its identification as a di-iron carboxylate protein and the generation of a structural model for the protein. A comparative analysis using a larger dataset identified 35 additional amino acids that are conserved in all AOXs examined, 30 of which have not been investigated to date. I hypothesize that these residues will be involved in the quinol terminal oxidase activity or membrane association of AOX. Major differences in AOX protein sequences between kingdoms are revealed, and it is hypothesized that two angiosperm-specific domains may be responsible for the non-covalent dimerization of AOX, whereas two indels in the aplastidic AOXs may play a role in their post-translational regulation. A scheme for predicting whether a particular AOX protein will be recognized by the alternative oxidase monoclonal antibody generated against the AOX of Sauromatum guttatum (Voodoo lily) is presented. The number of functional sites in AOX is greater than expected, and determining the structure of AOX will prove extremely valuable to future research.
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Affiliation(s)
- Allison E McDonald
- Department of Biology, The University of Western Ontario, 1151 Richmond St. N., London, Ontario N6A5B7, Canada.
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10
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A novel functional element in the N-terminal region of Arum concinnatum alternative oxidase is indispensable for catalytic activity of the enzyme in HeLa cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1797:20-8. [PMID: 19643077 DOI: 10.1016/j.bbabio.2009.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 07/14/2009] [Accepted: 07/21/2009] [Indexed: 11/20/2022]
Abstract
Alternative oxidase (AOX) is a quinol-oxygen oxidoreductase, which is known to possess a dicarboxylate diiron reaction center held in structurally postulated alpha-helical bundle. However, little is known about the structural or functional features of its N-terminal region in any organism, with the exception of a regulatory cysteine residue (CysI) in angiosperm plants. Here, we show that transcripts of two AOX1 isozymes (AcoAOX1a and AcoAOX1b) are coexpressed in thermogenic appendices of Arum concinnatum, while their enzymatic activities seem to be distinct. Namely, AcoAOX1a, an abundantly expressed transcript in vivo, shows an apparent cyanide-insensitive and n-propyl gallate-sensitive respiration during ectopic expression of the protein in HeLa cells, whereas AcoAOX1b exhibits a lower transcript expression, and appears to be totally inactive as AOX at the protein level. Our functional analyses further reveal that an E83K substitution in AcoAOX1b, which is located far upstream of CysI in the N-terminal region, is the cause of this loss of function. These results suggest the presence of a naturally occurring inactive AOX homologue in thermogenic plants. Accordingly, our results further imply that the N-terminal region of the AOX protein functionally contributes to the dynamic activities of respiratory control within the mitochondria.
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11
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Umbach AL, Lacey EP, Richter SJ. Temperature-sensitive alternative oxidase protein content and its relationship to floral reflectance in natural Plantago lanceolata populations. THE NEW PHYTOLOGIST 2008; 181:662-671. [PMID: 19021863 DOI: 10.1111/j.1469-8137.2008.02683.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In many plant species, the alternative respiratory pathway consisting of alternative oxidase (AOX) is affected by growth temperature. The adaptive significance of this temperature-sensitivity is unresolved. Here, leaf and spike (flower cluster) AOX protein content and spike/floral reflectance of genotypes from European Plantago lanceolata populations found in regions differing in reproductive season temperatures were measured. Cloned genotypes grown at controlled warm and cool temperatures were used to assess the natural within- and between-population variation in AOX content, temperature-sensitive phenotypic plasticity in content, and the relationship between AOX and temperature-sensitive floral/spike reflectance. AOX content and plasticity were genetically variable. Leaf AOX content, although greater at cool temperature, was relatively low and not statistically different across populations. Spike AOX content was greater than in leaves. Spike AOX plasticity differed significantly among populations and climate-types and showed significant negative correlation with floral reflectance plasticity, which also varied among populations. Genotypes with more AOX at cool than at warm temperature had greater floral reflectance plasticity; genotypes with relatively more AOX at warm temperature had less floral reflectance plasticity. The data support the hypothesis that plasticity of AOX content in reproductive tissues is associated with long-term thermal acclimatization.
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Affiliation(s)
- Ann L Umbach
- DCMB Group/Biology Department, Box 90338, Duke University, Durham, NC, 27708, USA
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12
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Xu C, Moellering ER, Fan J, Benning C. Mutation of a mitochondrial outer membrane protein affects chloroplast lipid biosynthesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 54:163-175. [PMID: 18208519 DOI: 10.1111/j.1365-313x.2008.03417.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Lipid biosynthesis in plant cells is associated with various organelles, and maintenance of cell lipid homeostasis requires nimble regulation and coordination. In plants, environmental cues such as phosphate limitation require readjustment of the lipid biosynthetic machinery to substitute phospholipids by non-phosphorous glycolipids. Biosynthesis of the galactoglycerolipids predominant in plants proceeds by a constitutive and an alternative pathway that is known to be induced in response to phosphate deprivation. Plant lipid galactosyltransferases involved in both pathways are associated with the plastid envelope membranes and are encoded by nuclear genes. To identify mechanisms governing the activity of the alternative galactoglycerolipid pathway, a genetic suppressor screen was conducted in the background of the digalactolipid-deficient dgd1 mutant of Arabidopsis. A suppressor line that partially restored digalactoglycerolipid content in the dgd1 background carries a point mutation in a mitochondrial protein, which was tentatively designated DGD1 SUPPRESSOR 1 (DGS1). Presumed orthologs of this protein are present in plants, algae and fungi, but its molecular function is not yet known. In the dgd1 dgs1 double mutant, expression of nuclear genes encoding enzymes of the alternative galactoglycerolipid pathway is increased and hydrogen peroxide levels are elevated. This increase in hydrogen peroxide is proposed to be the reason for activation of the alternative pathway in the dgd1 dgs1 double mutant. Accordingly, hydrogen peroxide and treatments producing reactive oxygen also activate the alternative pathway in the wild-type. These results likely implicate the production of reactive oxygen in the regulation of the alternative galactoglycerolipid pathway in plants.
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Affiliation(s)
- Changcheng Xu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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13
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Magnani T, Soriani FM, Martins VP, Nascimento AM, Tudella VG, Curti C, Uyemura SA. Cloning and functional expression of the mitochondrial alternative oxidase ofAspergillus fumigatusand its induction by oxidative stress. FEMS Microbiol Lett 2007; 271:230-8. [PMID: 17425662 DOI: 10.1111/j.1574-6968.2007.00716.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Aspergillus fumigatus possesses a branched mitochondrial electron transport chain, with both cyanide-sensitive and -insensitive oxygen-consumption activities. Mitochondrial reactive oxygen species mediate signaling for alternative oxidase (AOX) expression. A 1173 bp-long Afaox gene encoding a 40 kDa protein has been cloned and identified. Recombinant constructs containing the Afaox ORF were transformed into Escherichia coli and Saccharomyces cerevisiae for heterologous expression. In A. fumigatus, AOX activity and mRNA expression were both induced with menadione or paraquat, suggesting an important role of AOX under oxidative stress. Therefore, positive transformants showed a cyanide-resistant and salicylhydroxamic acid-sensitive respiration, whereas in control cells the oxygen uptake was completely inhibited after KCN addition.
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Affiliation(s)
- T Magnani
- Dep Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, SP, Brazil
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14
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Elhafez D, Murcha MW, Clifton R, Soole KL, Day DA, Whelan J. Characterization of Mitochondrial Alternative NAD(P)H Dehydrogenases in Arabidopsis: Intraorganelle Location and Expression. ACTA ACUST UNITED AC 2006; 47:43-54. [PMID: 16258072 DOI: 10.1093/pcp/pci221] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The intramitochondrial location of putative type II NAD(P)H dehydrogenases (NDs) in Arabidopsis was investigated by measuring the ability of isolated mitochondria to take up precursor proteins generated from cDNAs using an in vitro translation system. The mature proteins of NDA1, NDA2 and NDC1 were judged to be located on the inside of the inner membrane because they were protected from protease added after the mitochondrial outer membrane had been ruptured. In contrast, NDB1, NDB2 and NDB4 were not protected from protease digestion in mitochondria with ruptured outer membranes and were deemed to be located on the outside of the inner membrane. Expression of all ND genes was measured using quantitative reverse transcription-PCR (RT-PCR) to determine transcript abundance, and compared with expression of alternative oxidase, uncoupler proteins and selected components of the oxidative phosphorylation complexes. NDA1 and NDB2 were the most prominently expressed members in a variety of tissues, and were up-regulated in the early daytime in a diurnal manner. Analysis of array data suggested that NDA1 clustered closest to the gene encoding the P-subunit of glycine decarboxylase. Taken together with the diurnal regulation of NDA1 observed here and in other studies, this suggests that NDA1 plays a role in integrating metabolic activities of chloroplasts and mitochondria. NDA2, NDB2 and Aox1a were up-regulated in a coordinated manner under various treatments, potentially forming a complete respiratory chain capable of oxidizing matrix and cytosolic NAD(P)H. NDB1 and NDC1 were down-regulated under the same conditions and may be regarded as housekeeping genes.
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Affiliation(s)
- Dina Elhafez
- ARC Centre of Excellence in Plant Energy Biology, CMS Building M310, The University of Western Australia, Crawley
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15
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McDonald AE, Vanlerberghe GC. Alternative oxidase and plastoquinol terminal oxidase in marine prokaryotes of the Sargasso Sea. Gene 2005; 349:15-24. [PMID: 15777727 DOI: 10.1016/j.gene.2004.12.049] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2004] [Revised: 12/06/2004] [Accepted: 12/22/2004] [Indexed: 11/29/2022]
Abstract
Alternative oxidase (AOX) represents a non-energy conserving branch in mitochondrial electron transport while plastoquinol terminal oxidase (PTOX) represents a potential branch in photosynthetic electron transport. Using a metagenomics dataset, we have uncovered numerous and diverse AOX and PTOX genes from the Sargasso Sea. Sequence similarity, synteny and phylogenetic analyses indicate that the large majority of these genes are from prokaryotes. AOX appears to be widely distributed among marine Eubacteria while PTOX is widespread among strains of cyanobacteria closely related to the high-light adapted Prochlorococcus marinus MED4, as well as Synechococcus. The wide distribution of AOX and PTOX in marine prokaryotes may have important implications for productivity in the world's oceans.
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Affiliation(s)
- Allison E McDonald
- Department of Life Sciences, University of Toronto at Scarborough, 1265 Military Trail, Scarborough, ON Canada M1C 1A4
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16
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Roberts CW, Roberts F, Henriquez FL, Akiyoshi D, Samuel BU, Richards TA, Milhous W, Kyle D, McIntosh L, Hill GC, Chaudhuri M, Tzipori S, McLeod R. Evidence for mitochondrial-derived alternative oxidase in the apicomplexan parasite Cryptosporidium parvum: a potential anti-microbial agent target. Int J Parasitol 2004; 34:297-308. [PMID: 15003491 DOI: 10.1016/j.ijpara.2003.11.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2003] [Revised: 11/06/2003] [Accepted: 11/06/2003] [Indexed: 10/26/2022]
Abstract
The observation that Plasmodium falciparum possesses cyanide insensitive respiration that can be inhibited by salicylhydroxamic acid (SHAM) and propyl gallate is consistent with the presence of an alternative oxidase (AOX). However, the completion and annotation of the P. falciparum genome project did not identify any protein with convincing similarity to the previously described AOXs from plants, fungi or protozoa. We undertook a survey of the available apicomplexan genome projects in an attempt to address this anomaly. Putative AOX sequences were identified and sequenced from both type 1 and 2 strains of Cryptosporidium parvum. The gene encodes a polypeptide of 336 amino acids and has a predicted N-terminal transit sequence similar to that found in proteins targeted to the mitochondria of other species. The potential of AOX as a target for new anti-microbial agents for C. parvum is evident by the ability of SHAM and 8-hydroxyquinoline to inhibit in vitro growth of C. parvum. In spite of the lack of a good candidate for AOX in either the P. falciparum or Toxoplasma gondii genome projects, SHAM and 8-hydroxyquinoline were found to inhibit the growth of these parasites. Phylogenetic analysis suggests that AOX and the related protein immutans are derived from gene transfers from the mitochondrial endosymbiont and the chloroplast endosymbiont, respectively. These data are consistent with the functional localisation studies conducted thus far, which demonstrate mitochondrial localisation for some AOX and chloroplastidic localization for immutans. The presence of a mitochondrial compartment is further supported by the prediction of a mitochondrial targeting sequence at the N-terminus of the protein and MitoTracker staining of a subcellular compartment in trophozoite and meront stages. These results give insight into the evolution of AOX and demonstrate the potential of targeting the alternative pathway of respiration in apicomplexans.
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Affiliation(s)
- Craig W Roberts
- Department of Immunology, Strathclyde Institute for Biomedical Life Sciences, University of Strathclyde, Glasgow, Scotland, UK
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17
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Finnegan PM, Soole KL, Umbach AL. Alternative Mitochondrial Electron Transport Proteins in Higher Plants. PLANT MITOCHONDRIA: FROM GENOME TO FUNCTION 2004. [DOI: 10.1007/978-1-4020-2400-9_9] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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18
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Veiga A, Arrabaça JD, Loureiro-Dias MC. Stress situations induce cyanide-resistant respiration in spoilage yeasts. J Appl Microbiol 2003; 95:364-71. [PMID: 12859770 DOI: 10.1046/j.1365-2672.2003.01992.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To investigate the conditions that promote the expression of cyanide-resistant respiration (CRR) in the spoilage yeasts Pichia membranifaciens and Debaryomyces hansenii. METHODS AND RESULTS CRR was detected by sensitivity of oxygen consumption to salicylhydroxamic acid. It was absent in both yeasts in the early exponential phase, but was triggered by several stress situations. Starvation under aerobic conditions, decreasing pH or incubation of the culture in a narrow temperature range below the maximum temperature for growth promoted the emergence of CRR in both yeasts. In D. hansenii, CRR was also induced by 1.5-2 mol l(-1) NaCl. Although the presence of H2O2 and menadione induced CRR, radical scavengers had no effect on the emergence of CRR. Also, the level of reactive oxygen species did not vary with the CRR activity. CONCLUSIONS Under aerobic conditions, a respiratory pathway alternative to the cytochrome chain is triggered by stress conditions in P. membranifaciens and D. hansenii. SIGNIFICANCE AND IMPACT OF THE STUDY The relationship between stress situations and CRR must be taken into account in studies on the performance of spoilage yeasts in the food processing environments where several forms of stress are common.
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Affiliation(s)
- A Veiga
- Dep. Botânica e Engenharia Biológica, Instituto Superior de Agronomia, Lisboa, and Centro de Eng. Biológica, Fac. Ciências Lisboa, Lisboa, Portugal
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19
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Stenmark P, Nordlund P. A prokaryotic alternative oxidase present in the bacteriumNovosphingobium aromaticivorans. FEBS Lett 2003; 552:189-92. [PMID: 14527685 DOI: 10.1016/s0014-5793(03)00920-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The alternative oxidase (AOX) is a terminal oxidase present in the respiratory chain of all plants as well as some yeasts and trypanosomes, but has not previously been found in a prokaryote. We have identified an AOX homologue in Novosphingobium aromaticivorans, the first AOX found in a prokaryote. We have cloned the gene for the N. aromaticivorans AOX and showed it to have a terminal oxidase activity when heterologously expressed in Escherichia coli. We have also shown that this novel AOX is expressed in N. aromaticivorans cells, and that its expression level is greatly influenced by the oxygen level and carbon source of the growth media.
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Affiliation(s)
- Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University, Roslagstullsbacken 15, Albanova University Center, SE-10691 Stockholm, Sweden
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20
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McDonald AE, Sieger SM, Vanlerberghe GC. Methods and approaches to study plant mitochondrial alternative oxidase. PHYSIOLOGIA PLANTARUM 2002; 116:135-143. [PMID: 12354188 DOI: 10.1034/j.1399-3054.2002.1160201.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The alternative oxidase is a non-proton motive 'alternative' to electron transport through the cytochrome pathway. Despite its wasteful nature in terms of energy conservation, the pathway is likely present throughout the plant kingdom and appears to be expressed in most plant tissues. A small alternative oxidase gene family exists, the members of which are differentially expressed in response to environmental, developmental and other cell signals. The alternative oxidase enzyme possesses tight biochemical regulatory properties that determine its ability to compete with the cytochrome pathway for electrons. Studies show that alternative oxidase can be a prominent component of total respiration in important crop species. All these characteristics suggest this pathway plays an important role in metabolism and/or other aspects of cell physiology. This brief review is an introduction to experimental methods and approaches applicable to different areas of alternative oxidase research. We hope it provides a framework for further investigation of this fascinating component of primary plant metabolism.
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Affiliation(s)
- Allison E. McDonald
- Division of Life Sciences and Department of Botany, University of Toronto at Scarborough, 1265 Military Trail, Scarborough, ON M1C 1A4, Canada
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21
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Vanlerberghe GC, Ordog SH. Alternative Oxidase: Integrating Carbon Metabolism and Electron Transport in Plant Respiration. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2002. [DOI: 10.1007/0-306-48138-3_11] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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22
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Millenaar FF, Gonzàlez-Meler MA, Fiorani F, Welschen R, Ribas-Carbo M, Siedow JN, Wagner AM, Lambers H. Regulation of alternative oxidase activity in six wild monocotyledonous species. An in vivo study at the whole root level. PLANT PHYSIOLOGY 2001; 126:376-87. [PMID: 11351100 PMCID: PMC102311 DOI: 10.1104/pp.126.1.376] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2000] [Revised: 10/20/2000] [Accepted: 01/23/2001] [Indexed: 05/17/2023]
Abstract
The activity of the alternative pathway is affected by a number of factors, including the level and reduction state of the alternative oxidase (AOX) protein, and the reduction state of the ubiquinone pool. To investigate the significance of these factors for the rate of alternative respiration in vivo, we studied root respiration of six wild monocotyledonous grass species that were grown under identical controlled conditions. The activity of the alternative pathway was determined using the oxygen isotope fractionation technique. In all species, the AOX protein was invariably in its reduced (high activity) state. There was no correlation between AOX activity and AOX protein concentration, ubiquinone (total, reduced, or oxidized) concentration, or the reduction state of the ubiquinone pool. However, when some of these factors are combined in a linear regression model, a good fit to AOX activity is obtained. The function of the AOX is still not fully understood. It is interesting that we found a positive correlation between the activity of the alternative pathway and relative growth rate; a possible explanation for this correlation is discussed. Inhibition of the AOX (with salicylhydroxamic acid) decreases respiration rates less than the activity present before inhibition (i.e. measured with the 18O-fractionation technique).
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Affiliation(s)
- F F Millenaar
- Plant Ecophysiology, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht, The Netherlands.
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23
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Joseph-Horne T, Hollomon DW, Wood PM. Fungal respiration: a fusion of standard and alternative components. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1504:179-95. [PMID: 11245784 DOI: 10.1016/s0005-2728(00)00251-6] [Citation(s) in RCA: 227] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In animals, electron transfer from NADH to molecular oxygen proceeds via large respiratory complexes in a linear respiratory chain. In contrast, most fungi utilise branched respiratory chains. These consist of alternative NADH dehydrogenases, which catalyse rotenone insensitive oxidation of matrix NADH or enable cytoplasmic NADH to be used directly. Many also contain an alternative oxidase that probably accepts electrons directly from ubiquinol. A few fungi lack Complex I. Although the alternative components are non-energy conserving, their organisation within the fungal electron transfer chain ensures that the transfer of electrons from NADH to molecular oxygen is generally coupled to proton translocation through at least one site. The alternative oxidase enables respiration to continue in the presence of inhibitors for ubiquinol:cytochrome c oxidoreductase and cytochrome c oxidase. This may be particularly important for fungal pathogens, since host defence mechanisms often involve nitric oxide, which, whilst being a potent inhibitor of cytochrome c oxidase, has no inhibitory effect on alternative oxidase. Alternative NADH dehydrogenases may avoid the active oxygen production associated with Complex I. The expression and activity regulation of alternative components responds to factors ranging from oxidative stress to the stage of fungal development.
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Affiliation(s)
- T Joseph-Horne
- Department of Biochemistry, School of Biomedical Sciences, University of Bristol, UK.
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24
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Kita K, Miyadera H, Saruta F, Miyoshi H. Parasite Mitochondria as a Target for Chemotherapy. ACTA ACUST UNITED AC 2001. [DOI: 10.1248/jhs.47.219] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Kiyoshi Kita
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo
| | - Hiroko Miyadera
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo
| | - Fumiko Saruta
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo
| | - Hideto Miyoshi
- Division of Applied Life Science, Graduate School of Agriculture, Kyoto University
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25
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Affourtit C, Heaney SP, Moore AL. Mitochondrial electron transfer in the wheat pathogenic fungus Septoria tritici: on the role of alternative respiratory enzymes in fungicide resistance. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1459:291-8. [PMID: 11004442 DOI: 10.1016/s0005-2728(00)00157-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Certain phytopathogenic fungi are able to express alternative NADH- and quinol-oxidising enzymes that are insensitive to inhibitors of the mitochondrial respiratory Complexes I and III. To assess the extent to which such enzymes confer tolerance to respiration-targeted fungicides, an understanding of mitochondrial electron transfer in these species is required. An isolation procedure has been developed which results in intact, active and coupled mitochondria from the wheat pathogen Septoria tritici, as evidenced by morphological and kinetic data. Exogenous NADH, succinate and malate/glutamate are readily oxidised, the latter activity being only partly (approx. 70%) sensitive to rotenone. Of particular importance was the finding that azoxystrobin (a strobilurin fungicide) potently inhibits fungal respiration at the level of Complex III. In some S. tritici strains investigated, a small but significant part of the respiratory activity (approx. 10%) is insensitive to antimycin A and azoxystrobin. Such resistant activity is sensitive to octyl gallate, a specific inhibitor of the plant alternative oxidase. This enzyme, however, could not be detected immunologically. On the basis of the above findings, a conceptual mitochondrial electron transfer chain is presented. Data are discussed in terms of developmental and environmental regulation of the composition of this chain.
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Affiliation(s)
- C Affourtit
- Department of Biochemistry, University of Sussex, Brighton, UK.
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26
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Umbach AL, Siedow JN. The cyanide-resistant alternative oxidases from the fungi Pichia stipitis and Neurospora crassa are monomeric and lack regulatory features of the plant enzyme. Arch Biochem Biophys 2000; 378:234-45. [PMID: 10860541 DOI: 10.1006/abbi.2000.1834] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Both plant and fungal mitochondria have cyanide-resistant alternative oxidases that use reductant from the mitochondrial ubiquinone pool to reduce oxygen to water in a reaction that conserves no energy for ATP synthesis. The dimeric plant alternative oxidase is relatively inactive when its subunits are linked by a disulfide bond. When this bond is reduced, the enzyme can then be stimulated by its activators, alpha-keto acids. A Cys in the N-terminal section of the protein is responsible for both of these features. We examined the alternative oxidases in mitochondria isolated from two fungi Neurospora crassa and Pichia stipitis for dimeric structure, ability to form an intermolecular disulfide, and sensitivity to alpha-keto acids. Neither of the two fungal alternative oxidases could be covalently linked by diamide, which induces disulfide bond formation between nearby Cys residues, nor could they be cross-linked by a Lys-specific reagent or glutaraldehyde at concentrations which cross-link the plant alternative oxidase dimer completely. Alternative oxidase activity in fungal mitochondria was not stimulated by the alpha-keto acids pyruvate and glyoxylate. Pyruvate did stimulate activity when succinate was the respiratory substrate, but this was not a direct effect on the alternative oxidase. In contrast, added GMP was a strong activator of fungal alternative oxidase activity. Analysis of plant and fungal alternative oxidase protein sequences revealed a unique domain of about 40 amino acids surrounding the regulatory Cys in the plant sequences that is not present in the fungal sequences. This domain may be where dimerization of the plant enzymes occurs. In contrast to plant enzymes, the fungal alternative oxidases studied here are monomeric and their activities are independent of alpha-keto acids.
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Affiliation(s)
- A L Umbach
- DCMB Group/Botany Department, Duke University, Durham, North Carolina 27708, USA
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