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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. Front Plant Sci 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] [What about the content of this article? (0)] [Affiliation(s)] [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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2
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Fan Y, Scafaro AP, Asao S, Furbank RT, Agostino A, Day DA, von Caemmerer S, Danila FR, Rug M, Webb D, Lee J, Atkin OK. Dark respiration rates are not determined by differences in mitochondrial capacity, abundance and ultrastructure in C 4 leaves. Plant Cell Environ 2022; 45:1257-1269. [PMID: 35048399 DOI: 10.1111/pce.14267] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 12/28/2021] [Indexed: 06/14/2023]
Abstract
Our understanding of the regulation of respiration in C4 plants, where mitochondria play different roles in the different types of C4 photosynthetic pathway, remains limited. We examined how leaf dark respiration rates (Rdark ), in the presence and absence of added malate, vary in monocots representing the three classical biochemical types of C4 photosynthesis (NADP-ME, NAD-ME and PCK) using intact leaves and extracted bundle sheath strands. In particular, we explored to what extent rates of Rdark are associated with mitochondrial number, volume and ultrastructure. Based on examination of a single species per C4 type, we found that the respiratory response of NAD-ME and PCK type bundle sheath strands to added malate was associated with differences in mitochondrial number, volume, and/or ultrastructure, while NADP-ME type bundle sheath strands did not respond to malate addition. In general, mitochondrial traits reflected the contributions mitochondria make to photosynthesis in the three C4 types. However, despite the obvious differences in mitochondrial traits, no clear correlation was observed between these traits and Rdark . We suggest that Rdark is primarily driven by cellular maintenance demands and not mitochondrial composition per se, in a manner that is somewhat independent of mitochondrial organic acid cycling in the light.
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Affiliation(s)
- Yuzhen Fan
- Research School of Biology, ARC Centre of Excellence in Plant Energy Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Andrew P Scafaro
- Research School of Biology, ARC Centre of Excellence in Plant Energy Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Shinichi Asao
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Robert T Furbank
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
- Research School of Biology, ARC Centre of Excellence for Translational Photosynthesis, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Antony Agostino
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - David A Day
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
| | - Susanne von Caemmerer
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
- Research School of Biology, ARC Centre of Excellence for Translational Photosynthesis, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Florence R Danila
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
- Research School of Biology, ARC Centre of Excellence for Translational Photosynthesis, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Melanie Rug
- Centre for Advanced Microscopy, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Daryl Webb
- Centre for Advanced Microscopy, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Jiwon Lee
- Centre for Advanced Microscopy, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Owen K Atkin
- Research School of Biology, ARC Centre of Excellence in Plant Energy Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
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3
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Fan Y, Asao S, Furbank RT, von Caemmerer S, Day DA, Tcherkez G, Sage TL, Sage RF, Atkin OK. The crucial roles of mitochondria in supporting C 4 photosynthesis. New Phytol 2022; 233:1083-1096. [PMID: 34669188 DOI: 10.1111/nph.17818] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 10/18/2021] [Indexed: 06/13/2023]
Abstract
C4 photosynthesis involves a series of biochemical and anatomical traits that significantly improve plant productivity under conditions that reduce the efficiency of C3 photosynthesis. We explore how evolution of the three classical biochemical types of C4 photosynthesis (NADP-ME, NAD-ME and PCK types) has affected the functions and properties of mitochondria. Mitochondria in C4 NAD-ME and PCK types play a direct role in decarboxylation of metabolites for C4 photosynthesis. Mitochondria in C4 PCK type also provide ATP for C4 metabolism, although this role for ATP provision is not seen in NAD-ME type. Such involvement has increased mitochondrial abundance/size and associated enzymatic capacity, led to changes in mitochondrial location and ultrastructure, and altered the role of mitochondria in cellular carbon metabolism in the NAD-ME and PCK types. By contrast, these changes in mitochondrial properties are absent in the C4 NADP-ME type and C3 leaves, where mitochondria play no direct role in photosynthesis. From an eco-physiological perspective, rates of leaf respiration in darkness vary considerably among C4 species but does not differ systematically among the three C4 types. This review outlines further mitochondrial research in key areas central to the engineering of the C4 pathway into C3 plants and to the understanding of variation in rates of C4 dark respiration.
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Affiliation(s)
- Yuzhen Fan
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Shinichi Asao
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Robert T Furbank
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Susanne von Caemmerer
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - David A Day
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
| | - Guillaume Tcherkez
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
- Institut de Recherche en Horticulture et Semences, INRA and University of Angers, Beaucouzé, 49070, France
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Owen K Atkin
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
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Sweetman C, Selinski J, Miller TK, Whelan J, Day DA. Legume Alternative Oxidase Isoforms Show Differential Sensitivity to Pyruvate Activation. Front Plant Sci 2022; 12:813691. [PMID: 35111186 PMCID: PMC8801435 DOI: 10.3389/fpls.2021.813691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 12/27/2021] [Indexed: 05/29/2023]
Abstract
Alternative oxidase (AOX) is an important component of the plant respiratory pathway, enabling a route for electrons that bypasses the energy-conserving, ROS-producing complexes of the mitochondrial electron transport chain. Plants contain numerous isoforms of AOX, classified as either AOX1 or AOX2. AOX1 isoforms have received the most attention due to their importance in stress responses across a wide range of species. However, the propensity for at least one isoform of AOX2 to accumulate to very high levels in photosynthetic tissues of all legumes studied to date, suggests that this isoform has specialized roles, but we know little of its properties. Previous studies with sub-mitochondrial particles of soybean cotyledons and roots indicated that differential expression of GmAOX1, GmAOX2A, and GmAOX2D across tissues might confer different activation kinetics with pyruvate. We have investigated this using recombinantly expressed isoforms of soybean AOX in a previously described bacterial system (Selinski et al., 2016, Physiologia Plantarum 157, 264-279). Pyruvate activation kinetics were similar between the two GmAOX2 isoforms but differed substantially from those of GmAOX1, suggesting that selective expression of AOX1 and 2 could determine the level of AOX activity. However, this alone cannot completely explain the differences seen in sub-mitochondrial particles isolated from different legume tissues and possible reasons for this are discussed.
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Affiliation(s)
- Crystal Sweetman
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Jennifer Selinski
- Department of Plant Cell Biology, Botanical Institute, Christian-Albrecht University of Kiel, Kiel, Germany
| | - Troy K. Miller
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - James Whelan
- Department of Animal, Plant, and Soil Science, School of Soil Science, La Trobe University, Bundoora, VIC, Australia
| | - David A. Day
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
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5
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Booth NJ, Smith PMC, Ramesh SA, Day DA. Malate Transport and Metabolism in Nitrogen-Fixing Legume Nodules. Molecules 2021; 26:6876. [PMID: 34833968 PMCID: PMC8618214 DOI: 10.3390/molecules26226876] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 11/22/2022] Open
Abstract
Legumes form a symbiosis with rhizobia, a soil bacterium that allows them to access atmospheric nitrogen and deliver it to the plant for growth. Biological nitrogen fixation occurs in specialized organs, termed nodules, that develop on the legume root system and house nitrogen-fixing rhizobial bacteroids in organelle-like structures termed symbiosomes. The process is highly energetic and there is a large demand for carbon by the bacteroids. This carbon is supplied to the nodule as sucrose, which is broken down in nodule cells to organic acids, principally malate, that can then be assimilated by bacteroids. Sucrose may move through apoplastic and/or symplastic routes to the uninfected cells of the nodule or be directly metabolised at the site of import within the vascular parenchyma cells. Malate must be transported to the infected cells and then across the symbiosome membrane, where it is taken up by bacteroids through a well-characterized dct system. The dicarboxylate transporters on the infected cell and symbiosome membranes have been functionally characterized but remain unidentified. Proteomic and transcriptomic studies have revealed numerous candidates, but more work is required to characterize their function and localise the proteins in planta. GABA, which is present at high concentrations in nodules, may play a regulatory role, but this remains to be explored.
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Affiliation(s)
- Nicholas J. Booth
- College of Science & Engineering, Flinders University, GPO Box 5100, Adelaide, SA 5001, Australia; (N.J.B.); (S.A.R.)
| | | | - Sunita A. Ramesh
- College of Science & Engineering, Flinders University, GPO Box 5100, Adelaide, SA 5001, Australia; (N.J.B.); (S.A.R.)
| | - David A. Day
- College of Science & Engineering, Flinders University, GPO Box 5100, Adelaide, SA 5001, Australia; (N.J.B.); (S.A.R.)
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6
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Gavrin A, Loughlin PC, Brear E, Griffith OW, Bedon F, Suter Grotemeyer M, Escudero V, Reguera M, Qu Y, Mohd-Noor SN, Chen C, Osorio MB, Rentsch D, González-Guerrero M, Day DA, Smith PMC. Soybean Yellow Stripe-like 7 is a symbiosome membrane peptide transporter important for nitrogen fixation. Plant Physiol 2021; 186:581-598. [PMID: 33619553 PMCID: PMC8154080 DOI: 10.1093/plphys/kiab044] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 01/21/2021] [Indexed: 05/05/2023]
Abstract
Legumes form a symbiosis with rhizobia that convert atmospheric nitrogen (N2) to ammonia and provide it to the plant in return for a carbon and nutrient supply. Nodules, developed as part of the symbiosis, harbor rhizobia that are enclosed in a plant-derived symbiosome membrane (SM) to form an organelle-like structure called the symbiosome. In mature nodules exchanges between the symbionts occur across the SM. Here we characterize Yellow Stripe-like 7 (GmYSL7), a Yellow stripe-like family member localized on the SM in soybean (Glycine max) nodules. It is expressed specifically in infected cells with expression peaking soon after nitrogenase becomes active. Unlike most YSL family members, GmYSL7 does not transport metals complexed with phytosiderophores. Rather, it transports oligopeptides of between four and 12 amino acids. Silencing GmYSL7 reduces nitrogenase activity and blocks infected cell development so that symbiosomes contain only a single bacteroid. This indicates the substrate of YSL7 is required for proper nodule development, either by promoting symbiosome development directly or by preventing inhibition of development by the plant. RNAseq of nodules where GmYSL7 was silenced suggests that the plant initiates a defense response against rhizobia with genes encoding proteins involved in amino acid export downregulated and some transcripts associated with metal homeostasis altered. These changes may result from the decrease in nitrogen fixation upon GmYSL7 silencing and suggest that the peptide(s) transported by GmYSL7 monitor the functional state of the bacteroids and regulate nodule metabolism and transport processes accordingly. Further work to identify the physiological substrate for GmYSL7 will allow clarification of this role.
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Affiliation(s)
- Aleksandr Gavrin
- Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, UK
| | - Patrick C Loughlin
- School of Life and Environmental Science, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Ella Brear
- School of Life and Environmental Science, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Oliver W Griffith
- Department of Biological Sciences, Macquarie University, Macquarie Park, NSW 2109, Australia
| | - Frank Bedon
- School of Life Sciences, La Trobe University, Bundoora, Victoria 3083, Australia
| | | | - Viviana Escudero
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA). Universidad Politécnica de Madrid, Campus de Montegancedo, Crta, 28223 Pozuelo de Alarcón (Madrid), Spain
| | - Maria Reguera
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA). Universidad Politécnica de Madrid, Campus de Montegancedo, Crta, 28223 Pozuelo de Alarcón (Madrid), Spain
| | - Yihan Qu
- School of Life and Environmental Science, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Siti N Mohd-Noor
- School of Life and Environmental Science, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Chi Chen
- School of Life and Environmental Science, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Marina Borges Osorio
- School of Life Sciences, La Trobe University, Bundoora, Victoria 3083, Australia
| | - Doris Rentsch
- IPS, Molecular Plant Physiology, University of Bern, Altenbergrain 21, 3013 Bern, Switzerland
| | - Manuel González-Guerrero
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA). Universidad Politécnica de Madrid, Campus de Montegancedo, Crta, 28223 Pozuelo de Alarcón (Madrid), Spain
| | - David A Day
- College of Science and Engineering, Flinders University, Bedford Park, Adelaide, SA, Australia
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Abstract
Iron is an essential nutrient for the legume-rhizobia symbiosis and nitrogen-fixing bacteroids within root nodules of legumes have a very high demand for the metal. Within the infected cells of nodules, the bacteroids are surrounded by a plant membrane to form an organelle-like structure called the symbiosome. In this review, we focus on how iron is transported across the symbiosome membrane and accessed by the bacteroids.
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Affiliation(s)
- David A. Day
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
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8
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Sweetman C, Khassanova G, Miller TK, Booth NJ, Kurishbayev A, Jatayev S, Gupta NK, Langridge P, Jenkins CLD, Soole KL, Day DA, Shavrukov Y. Salt-induced expression of intracellular vesicle trafficking genes, CaRab-GTP, and their association with Na + accumulation in leaves of chickpea (Cicer arietinum L.). BMC Plant Biol 2020; 20:183. [PMID: 33050887 PMCID: PMC7557026 DOI: 10.1186/s12870-020-02331-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Accepted: 03/06/2020] [Indexed: 05/12/2023]
Abstract
BACKGROUND Chickpea is an important legume and is moderately tolerant to salinity stress during the growing season. However, the level and mechanisms for salinity tolerance can vary among accessions and cultivars. A large family of CaRab-GTP genes, previously identified in chickpea, is homologous to intracellular vesicle trafficking superfamily genes that play essential roles in response to salinity stress in plants. RESULTS To determine which of the gene family members are involved in the chickpea salt response, plants from six selected chickpea accessions (Genesis 836, Hattrick, ICC12726, Rupali, Slasher and Yubileiny) were exposed to salinity stress and expression profiles resolved for the major CaRab-GTP gene clades after 5, 9 and 15 days of salt exposure. Gene clade expression profiles (using degenerate primers targeting all members of each clade) were tested for their relationship to salinity tolerance measures, namely plant biomass and Na+ accumulation. Transcripts representing 11 out of the 13 CaRab clades could be detected by RT-PCR, but only six (CaRabA2, -B, -C, -D, -E and -H) could be quantified using qRT-PCR due to low expression levels or poor amplification efficiency of the degenerate primers for clades containing several gene members. Expression profiles of three gene clades, CaRabB, -D and -E, were very similar across all six chickpea accessions, showing a strongly coordinated network. Salt-induced enhancement of CaRabA2 expression at 15 days showed a very strong positive correlation (R2 = 0.905) with Na+ accumulation in leaves. However, salinity tolerance estimated as relative plant biomass production compared to controls, did not correlate with Na+ accumulation in leaves, nor with expression profiles of any of the investigated CaRab-GTP genes. CONCLUSION A coordinated network of CaRab-GTP genes, which are likely involved in intracellular trafficking, are important for the salinity stress response of chickpea plants.
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Affiliation(s)
- Crystal Sweetman
- College of Science and Engineering, Biological Sciences, Flinders University, Adelaide, Australia
| | - Gulmira Khassanova
- Faculty of Agronomy, S. Seifullin Kazakh AgroTechnical University, Nur-Sultan, Kazakhstan
| | - Troy K Miller
- College of Science and Engineering, Biological Sciences, Flinders University, Adelaide, Australia
| | - Nicholas J Booth
- College of Science and Engineering, Biological Sciences, Flinders University, Adelaide, Australia
| | - Akhylbek Kurishbayev
- Faculty of Agronomy, S. Seifullin Kazakh AgroTechnical University, Nur-Sultan, Kazakhstan
| | - Satyvaldy Jatayev
- Faculty of Agronomy, S. Seifullin Kazakh AgroTechnical University, Nur-Sultan, Kazakhstan.
| | - Narendra K Gupta
- College of Agriculture, SKN Agriculture University, Jobner, Rajasthan, India
| | | | - Colin L D Jenkins
- College of Science and Engineering, Biological Sciences, Flinders University, Adelaide, Australia
| | - Kathleen L Soole
- College of Science and Engineering, Biological Sciences, Flinders University, Adelaide, Australia
| | - David A Day
- College of Science and Engineering, Biological Sciences, Flinders University, Adelaide, Australia
- School of Life Science, AgriBio, LaTrobe University, Melbourne, Australia
| | - Yuri Shavrukov
- College of Science and Engineering, Biological Sciences, Flinders University, Adelaide, Australia.
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Brear EM, Bedon F, Gavrin A, Kryvoruchko IS, Torres-Jerez I, Udvardi MK, Day DA, Smith PMC. GmVTL1a is an iron transporter on the symbiosome membrane of soybean with an important role in nitrogen fixation. New Phytol 2020; 228:667-681. [PMID: 32533710 DOI: 10.1111/nph.16734] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 05/27/2020] [Indexed: 05/07/2023]
Abstract
Legumes establish symbiotic relationships with soil bacteria (rhizobia), housed in nodules on roots. The plant supplies carbon substrates and other nutrients to the bacteria in exchange for fixed nitrogen. The exchange occurs across a plant-derived symbiosome membrane (SM), which encloses rhizobia to form a symbiosome. Iron supplied by the plant is crucial for rhizobial enzyme nitrogenase that catalyses nitrogen fixation, but the SM iron transporter has not been identified. We use yeast complementation, real-time PCR and proteomics to study putative soybean (Glycine max) iron transporters GmVTL1a and GmVTL1b and have characterized the role of GmVTL1a using complementation in plant mutants, hairy root transformation and microscopy. GmVTL1a and GmVTL1b are members of the vacuolar iron transporter family and homologous to Lotus japonicus SEN1 (LjSEN1), which is essential for nitrogen fixation. GmVTL1a expression is enhanced in nodule infected cells and both proteins are localized to the SM. GmVTL1a transports iron in yeast and restores nitrogen fixation when expressed in the Ljsen1 mutant. Three GmVTL1a amino acid substitutions that block nitrogen fixation in Ljsen1 plants reduce iron transport in yeast. We conclude GmVTL1a is responsible for transport of iron across the SM to bacteroids and plays a crucial role in the nitrogen-fixing symbiosis.
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Affiliation(s)
- Ella M Brear
- School of Life and Environmental Science, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Frank Bedon
- Department of Animal, Plant and Soil Sciences, School of Life Sciences, La Trobe University, Bundoora, VIC, 3083, Australia
| | - Aleksandr Gavrin
- School of Life and Environmental Science, The University of Sydney, Sydney, NSW, 2006, Australia
- Sainsbury Laboratory, University of Cambridge, Cambridge, CB2 1LR, UK
| | - Igor S Kryvoruchko
- Noble Research Institute, Ardmore, OK, 73401, USA
- Molecular Biology and Genetics, Boğaziçi University, Istanbul, Turkey
| | | | | | - David A Day
- College of Science and Engineering, Flinders University, Bedford Park, Adelaide, SA, 5042, Australia
| | - Penelope M C Smith
- Department of Animal, Plant and Soil Sciences, School of Life Sciences, La Trobe University, Bundoora, VIC, 3083, Australia
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10
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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11
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Rashid FAA, Crisp PA, Zhang Y, Berkowitz O, Pogson BJ, Day DA, Masle J, Dewar RC, Whelan J, Atkin OK, Scafaro AP. Molecular and physiological responses during thermal acclimation of leaf photosynthesis and respiration in rice. Plant Cell Environ 2020; 43:594-610. [PMID: 31860752 DOI: 10.1111/pce.13706] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/15/2019] [Accepted: 12/16/2019] [Indexed: 05/24/2023]
Abstract
To further our understanding of how sustained changes in temperature affect the carbon economy of rice (Oryza sativa), hydroponically grown plants of the IR64 cultivar were developed at 30°C/25°C (day/night) before being shifted to 25/20°C or 40/35°C. Leaf messenger RNA and protein abundance, sugar and starch concentrations, and gas-exchange and elongation rates were measured on preexisting leaves (PE) already developed at 30/25°C or leaves newly developed (ND) subsequent to temperature transfer. Following a shift in growth temperature, there was a transient adjustment in metabolic gene transcript abundance of PE leaves before homoeostasis was reached within 24 hr, aligning with Rdark (leaf dark respiratory CO2 release) and An (net CO2 assimilation) changes. With longer exposure, the central respiratory protein cytochrome c oxidase (COX) declined in abundance at 40/35°C. In contrast to Rdark , An was maintained across the three growth temperatures in ND leaves. Soluble sugars did not differ significantly with growth temperature, and growth was fastest with extended exposure at 40/35°C. The results highlight that acclimation of photosynthesis and respiration is asynchronous in rice, with heat-acclimated plants exhibiting a striking ability to maintain net carbon gain and growth when exposed to heat-wave temperatures, even while reducing investment in energy-conserving respiratory pathways.
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Affiliation(s)
- Fatimah Azzahra Ahmad Rashid
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
- Department of Biology, Faculty of Science and Mathematics, Sultan Idris Education University, Tanjung Malim, Malaysia
| | - Peter A Crisp
- Department of Plant and Microbial Biology, University of Minnesota, Saint Paul, Minnesota
| | - You Zhang
- CSIRO Plant Industry, Canberra, Australian Capital Territory, Australia
| | - Oliver Berkowitz
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, AgriBio Building, La Trobe University, Melbourne, Victoria, Australia
| | - Barry J Pogson
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - David A Day
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
- Department of Animal, Plant and Soil Sciences, AgriBio Building, La Trobe University, Melbourne, Victoria, Australia
| | - Josette Masle
- Research School of Biology, The Australian National University, Canberra, Australia
| | - Roderick C Dewar
- Research School of Biology, The Australian National University, Canberra, Australia
- Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, Helsinki, Finland
| | - James Whelan
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, AgriBio Building, La Trobe University, Melbourne, Victoria, Australia
| | - Owen K Atkin
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Andrew P Scafaro
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
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12
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Munns R, Day DA, Fricke W, Watt M, Arsova B, Barkla BJ, Bose J, Byrt CS, Chen ZH, Foster KJ, Gilliham M, Henderson SW, Jenkins CLD, Kronzucker HJ, Miklavcic SJ, Plett D, Roy SJ, Shabala S, Shelden MC, Soole KL, Taylor NL, Tester M, Wege S, Wegner LH, Tyerman SD. Energy costs of salt tolerance in crop plants. New Phytol 2020; 225:1072-1090. [PMID: 31004496 DOI: 10.1111/nph.15864] [Citation(s) in RCA: 166] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/25/2019] [Indexed: 05/21/2023]
Abstract
Agriculture is expanding into regions that are affected by salinity. This review considers the energetic costs of salinity tolerance in crop plants and provides a framework for a quantitative assessment of costs. Different sources of energy, and modifications of root system architecture that would maximize water vs ion uptake are addressed. Energy requirements for transport of salt (NaCl) to leaf vacuoles for osmotic adjustment could be small if there are no substantial leaks back across plasma membrane and tonoplast in root and leaf. The coupling ratio of the H+ -ATPase also is a critical component. One proposed leak, that of Na+ influx across the plasma membrane through certain aquaporin channels, might be coupled to water flow, thus conserving energy. For the tonoplast, control of two types of cation channels is required for energy efficiency. Transporters controlling the Na+ and Cl- concentrations in mitochondria and chloroplasts are largely unknown and could be a major energy cost. The complexity of the system will require a sophisticated modelling approach to identify critical transporters, apoplastic barriers and root structures. This modelling approach will inform experimentation and allow a quantitative assessment of the energy costs of NaCl tolerance to guide breeding and engineering of molecular components.
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Affiliation(s)
- Rana Munns
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, and School of Agriculture and Environment, The University of Western Australia, Crawley, WA, 6009, Australia
- CSIRO Agriculture and Food, Canberra, ACT, 2601, Australia
| | - David A Day
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
| | - Wieland Fricke
- School of Biology and Environmental Sciences, University College Dublin (UCD), Dublin, 4, Ireland
| | - Michelle Watt
- Plant Sciences, Institute of Bio and Geosciences, Forschungszentrum Juelich, Helmholtz Association, 52425, Juelich, Germany
| | - Borjana Arsova
- Plant Sciences, Institute of Bio and Geosciences, Forschungszentrum Juelich, Helmholtz Association, 52425, Juelich, Germany
| | - Bronwyn J Barkla
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW, 2481, Australia
| | - Jayakumar Bose
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Caitlin S Byrt
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
- Research School of Biology, Australian National University, Canberra, ACT, 2600, Australia
| | - Zhong-Hua Chen
- School of Science and Health, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Kylie J Foster
- Phenomics and Bioinformatics Research Centre, School of Information Technology and Mathematical Sciences, University of South Australia, Mawson Lakes, SA, 5095, Australia
| | - Matthew Gilliham
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Sam W Henderson
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Urrbrae, SA, 5064, Australia
| | - Colin L D Jenkins
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
| | - Herbert J Kronzucker
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Stanley J Miklavcic
- Phenomics and Bioinformatics Research Centre, School of Information Technology and Mathematical Sciences, University of South Australia, Mawson Lakes, SA, 5095, Australia
| | - Darren Plett
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Stuart J Roy
- Australian Research Council (ARC) Industrial Transformation Research Hub for Wheat in a Hot and Dry Climate, School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA, 5064, Australia
| | - Sergey Shabala
- Tasmanian Institute for Agriculture, University of Tasmania, Private Bag 54, Hobart, Tas., 7001, Australia
- International Centre for Environmental Membrane Biology, Foshan University, Foshan, 528000, China
| | - Megan C Shelden
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Kathleen L Soole
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
| | - Nicolas L Taylor
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Molecular Sciences and Institute of Agriculture, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Mark Tester
- Biological and Environmental Sciences & Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Stefanie Wege
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Lars H Wegner
- Karlsruhe Institute of Technology, Institute for Pulsed Power and Microwave Technology (IHM), D-76344, Eggenstein-Leopoldshafen, Germany
| | - Stephen D Tyerman
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
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13
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Sweetman C, Waterman CD, Rainbird BM, Smith PMC, Jenkins CD, Day DA, Soole KL. AtNDB2 Is the Main External NADH Dehydrogenase in Mitochondria and Is Important for Tolerance to Environmental Stress. Plant Physiol 2019; 181:774-788. [PMID: 31409698 PMCID: PMC6776847 DOI: 10.1104/pp.19.00877] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 07/23/2019] [Indexed: 05/02/2023]
Abstract
In addition to the classical electron transport pathway coupled to ATP synthesis, plant mitochondria have an alternative pathway that involves type II NAD(P)H dehydrogenases (NDs) and alternative oxidase (AOX). This alternative pathway participates in thermogenesis in select organs of some species and is thought to help prevent cellular damage during exposure to environmental stress. Here, we investigated the function and role of one alternative path component, AtNDB2, using a transgenic approach in Arabidopsis (Arabidopsis thaliana). Disruption of AtNDB2 expression via T-DNA insertion led to a 90% decrease of external NADH oxidation in isolated mitochondria. Overexpression of AtNDB2 led to increased AtNDB2 protein abundance in mitochondria but did not enhance external NADH oxidation significantly unless AtAOX1A was concomitantly overexpressed and activated, demonstrating a functional link between these enzymes. Plants lacking either AtAOX1A or AtNDB2 were more sensitive to combined drought and elevated light treatments, whereas plants overexpressing these components showed increased tolerance and capacity for poststress recovery. We conclude that AtNDB2 is the predominant external NADH dehydrogenase in mitochondria and together with AtAOX1A forms a complete, functional, nonphosphorylating pathway of electron transport, whose operation enhances tolerance to environmental stress. This study demonstrates that at least one of the alternative NDs, as well as AOX, are important for the stress response.
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Affiliation(s)
- Crystal Sweetman
- College of Science and Engineering, Flinders University of South Australia, Adelaide, South Australia 5042, Australia
| | - Christopher D Waterman
- College of Science and Engineering, Flinders University of South Australia, Adelaide, South Australia 5042, Australia
| | - Barry M Rainbird
- College of Science and Engineering, Flinders University of South Australia, Adelaide, South Australia 5042, Australia
| | - Penelope M C Smith
- Department of Animal, Plant, and Soil Sciences, School of Life Sciences, Latrobe University, Bundoora, Victoria 3083, Australia
| | - Colin D Jenkins
- College of Science and Engineering, Flinders University of South Australia, Adelaide, South Australia 5042, Australia
| | - David A Day
- College of Science and Engineering, Flinders University of South Australia, Adelaide, South Australia 5042, Australia
| | - Kathleen L Soole
- College of Science and Engineering, Flinders University of South Australia, Adelaide, South Australia 5042, Australia
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14
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Sweetman C, Soole KL, Jenkins CLD, Day DA. Genomic structure and expression of alternative oxidase genes in legumes. Plant Cell Environ 2019; 42:71-84. [PMID: 29424926 DOI: 10.1111/pce.13161] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/22/2018] [Accepted: 01/25/2018] [Indexed: 05/26/2023]
Abstract
Mitochondria isolated from chickpea (Cicer arietinum) possess substantial alternative oxidase (AOX) activity, even in non-stressed plants, and one or two AOX protein bands were detected immunologically, depending on the organ. Four different AOX isoforms were identified in the chickpea genome: CaAOX1 and CaAOX2A, B and D. CaAOX2A was the most highly expressed form and was strongly expressed in photosynthetic tissues, whereas CaAOX2D was found in all organs examined. These results are very similar to those of previous studies with soybean and siratro. Searches of available databases showed that this pattern of AOX genes and their expression was common to at least 16 different legume species. The evolution of the legume AOX gene family is discussed, as is the in vivo impact of an inherently high AOX capacity in legumes on growth and responses to environmental stresses.
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Affiliation(s)
- Crystal Sweetman
- Australian Research Council Industrial Transformation Research Hub, Legumes for Sustainable Agriculture, College of Science and Engineering, Flinders University of South Australia, Adelaide, South Australia, GPO Box 2001, Australia
| | - Kathleen L Soole
- Australian Research Council Industrial Transformation Research Hub, Legumes for Sustainable Agriculture, College of Science and Engineering, Flinders University of South Australia, Adelaide, South Australia, GPO Box 2001, Australia
| | - Colin L D Jenkins
- Australian Research Council Industrial Transformation Research Hub, Legumes for Sustainable Agriculture, College of Science and Engineering, Flinders University of South Australia, Adelaide, South Australia, GPO Box 2001, Australia
| | - David A Day
- Australian Research Council Industrial Transformation Research Hub, Legumes for Sustainable Agriculture, College of Science and Engineering, Flinders University of South Australia, Adelaide, South Australia, GPO Box 2001, Australia
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15
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Tyerman SD, Munns R, Fricke W, Arsova B, Barkla BJ, Bose J, Bramley H, Byrt C, Chen Z, Colmer TD, Cuin T, Day DA, Foster KJ, Gilliham M, Henderson SW, Horie T, Jenkins CLD, Kaiser BN, Katsuhara M, Plett D, Miklavcic SJ, Roy SJ, Rubio F, Shabala S, Shelden M, Soole K, Taylor NL, Tester M, Watt M, Wege S, Wegner LH, Wen Z. Energy costs of salinity tolerance in crop plants. New Phytol 2019; 221:25-29. [PMID: 30488600 DOI: 10.1111/nph.15555] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Affiliation(s)
- Stephen D Tyerman
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Rana Munns
- ARC Centre of Excellence in Plant Energy Biology, and School of Agriculture and Environment, The University of Western Australia, Crawley, WA, 6009, Australia
- CSIRO Agriculture and Food, Canberra, ACT, 2601, Australia
| | - Wieland Fricke
- School of Biology and Environmental Sciences, University College Dublin (UCD), Dublin, 4, Ireland
| | - Borjana Arsova
- Plant Sciences, Institute of Bio and Geosciences, Forschungszentrum Jülich, Wilhelm-Johnen Strasse, 52425, Jülich, Germany
| | - Bronwyn J Barkla
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW, 2480, Australia
| | - Jayakumar Bose
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Helen Bramley
- Plant Breeding Institute, Sydney Institute of Agriculture & School of Life and Environmental Sciences, The University of Sydney, Narrabri, NSW, 2390, Australia
| | - Caitlin Byrt
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Zhonghua Chen
- School of Science and Health, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Timothy D Colmer
- School of Agriculture and Environment, ARC Industrial Transformation Research Hub on Legumes for Sustainable Agriculture, Faculty of Science, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Tracey Cuin
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, TAS, 7001, Australia
| | - David A Day
- College of Science & Engineering, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
| | - Kylie J Foster
- Phenomics and Bioinformatics Research Centre, University of South Australia, Mawson Lakes, SA, 5095, Australia
| | - Matthew Gilliham
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Sam W Henderson
- School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA, 5064, Australia
- CSIRO Agriculture and Food, Urrbrae, SA, 5064, Australia
| | - Tomoaki Horie
- Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano, 386-8567, Japan
| | - Colin L D Jenkins
- College of Sciences and Engineering, Flinders University of South Australia, Bedford Park, SA, 5042, Australia
| | - Brent N Kaiser
- School of Life and Environmental Science, University of Sydney, Camden, NSW, 2570, Australia
| | - Maki Katsuhara
- Institute of Plant Science and Resources, Okayama University, Kurashiki, 7100046, Japan
| | - Darren Plett
- School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA, 5064, Australia
- School of Agriculture and Food, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Stanley J Miklavcic
- Phenomics and Bioinformatics Research Centre, University of South Australia, Mawson Lakes, SA, 5095, Australia
| | - Stuart J Roy
- School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA, 5064, Australia
| | - Francisco Rubio
- Departamento de Nutrición Vegetal, CEBAS-CSIC-Campus de Espinardo, 30100, Murcia, Spain
| | - Sergey Shabala
- College of Science and Engineering, University of Tasmania, Private Bag 54, Hobart, TAS, 7001, Australia
| | - Megan Shelden
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Kathleen Soole
- College of Sciences and Engineering, Flinders University of South Australia, Bedford Park, SA, 5042, Australia
| | - Nicolas L Taylor
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Sciences and Institute of Agriculture, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Mark Tester
- Biological and Environmental Sciences & Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Michelle Watt
- Plant Sciences, Institute of Bio and Geosciences, Forschungszentrum Juelich, Helmholtz Association, 52425, Juelich, Germany
| | - Stefanie Wege
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Lars H Wegner
- Institute for Pulsed Power and Microwave Technology (IHM), Karlsruhe Institute of Technology, D-76344, Eggenstein-Leopoldshafen, Germany
| | - Zhengyu Wen
- School of Life and Environmental Science, University of Sydney, Camden, NSW, 2570, Australia
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Selinski J, Scheibe R, Day DA, Whelan J. Alternative Oxidase Is Positive for Plant Performance. Trends Plant Sci 2018; 23:588-597. [PMID: 29665989 DOI: 10.1016/j.tplants.2018.03.012] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 03/15/2018] [Accepted: 03/22/2018] [Indexed: 05/02/2023]
Abstract
The alternative pathway of mitochondrial electron transport, which terminates in the alternative oxidase (AOX), uncouples oxidation of substrate from mitochondrial ATP production, yet plant performance is improved under adverse growth conditions. AOX is regulated at different levels. Identification of regulatory transcription factors shows that Arabidopsis thaliana AOX1a is under strong transcriptional suppression. At the protein level, the primary structure is not optimised for activity. Maximal activity requires the presence of various metabolites, such as tricarboxylic acid-cycle intermediates that act in an isoform-specific manner. In this opinion article we propose that the regulatory mechanisms that keep AOX activity suppressed, at both the gene and protein level, are positive for plant performance due to the flexible short- and long-term fine-tuning.
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Affiliation(s)
- Jennifer Selinski
- Department of Animal, Plant, and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University Bundoora, VIC 3083, Australia.
| | - Renate Scheibe
- Division of Plant Physiology, Department of Biology/Chemistry, University of Osnabrueck, D-49069 Osnabrueck, Germany
| | - David A Day
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
| | - James Whelan
- Department of Animal, Plant, and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University Bundoora, VIC 3083, Australia
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17
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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18
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Selinski J, Hartmann A, Deckers-Hebestreit G, Day DA, Whelan J, Scheibe R. Alternative Oxidase Isoforms Are Differentially Activated by Tricarboxylic Acid Cycle Intermediates. Plant Physiol 2018; 176:1423-1432. [PMID: 29208641 PMCID: PMC5813554 DOI: 10.1104/pp.17.01331] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 11/30/2017] [Indexed: 05/18/2023]
Abstract
The cyanide-insensitive alternative oxidase (AOX) is a non-proton-pumping ubiquinol oxidase that catalyzes the reduction of oxygen to water and is posttranslationally regulated by redox mechanisms and 2-oxo acids. Arabidopsis (Arabidopsis thaliana) possesses five AOX isoforms (AOX1A-AOX1D and AOX2). AOX1D expression is increased in aox1a knockout mutants from Arabidopsis (especially after restriction of the cytochrome c pathway) but cannot compensate for the lack of AOX1A, suggesting a difference in the regulation of these isoforms. Therefore, we analyzed the different AOX isoenzymes with the aim to identify differences in their posttranslational regulation. Seven tricarboxylic acid cycle intermediates (citrate, isocitrate, 2-oxoglutarate, succinate, fumarate, malate, and oxaloacetate) were tested for their influence on AOX1A, AOX1C, and AOX1D wild-type protein activity using a refined in vitro system. AOX1C is insensitive to all seven organic acids, AOX1A and AOX1D are both activated by 2-oxoglutarate, but only AOX1A is additionally activated by oxaloacetate. Furthermore, AOX isoforms cannot be transformed to mimic one another by substituting the variable cysteine residues at position III in the protein. In summary, we show that AOX isoforms from Arabidopsis are differentially fine-regulated by tricarboxylic acid cycle metabolites (most likely depending on the amino-terminal region around the highly conserved cysteine residues known to be involved in regulation by the 2-oxo acids pyruvate and glyoxylate) and propose that this is the main reason why they cannot functionally compensate for each other.
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Affiliation(s)
- Jennifer Selinski
- Division of Plant Physiology, Department of Biology/Chemistry, University of Osnabrueck, D-49069 Osnabrueck, Germany
| | - Andreas Hartmann
- Division of Plant Physiology, Department of Biology/Chemistry, University of Osnabrueck, D-49069 Osnabrueck, Germany
| | - Gabriele Deckers-Hebestreit
- Division of Microbiology, Department of Biology/Chemistry, University of Osnabrueck, D-49069 Osnabrueck, Germany
| | - David A Day
- College of Science and Engineering, Flinders University, Adelaide, South Australia 5001, Australia
| | - James Whelan
- Department of Animal, Plant, and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, Victoria 3083, Australia
| | - Renate Scheibe
- Division of Plant Physiology, Department of Biology/Chemistry, University of Osnabrueck, D-49069 Osnabrueck, Germany
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19
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Lyu W, Selinski J, Li L, Day DA, Murcha MW, Whelan J, Wang Y. Isolation and Respiratory Measurements of Mitochondria from Arabidopsis thaliana. J Vis Exp 2018. [PMID: 29364229 DOI: 10.3791/56627] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Mitochondria are essential organelles involved in numerous metabolic pathways in plants, most notably the production of adenosine triphosphate (ATP) from the oxidation of reduced compounds such as nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FADH2). The complete annotation of the Arabidopsis thaliana genome has established it as the most widely used plant model system, and thus the need to purify mitochondria from a variety of organs (leaf, root, or flower) is necessary to fully utilize the tools that are now available for Arabidopsis to study mitochondrial biology. Mitochondria are isolated by homogenization of the tissue using a variety of approaches, followed by a series of differential centrifugation steps producing a crude mitochondrial pellet that is further purified using continuous colloidal density gradient centrifugation. The colloidal density material is subsequently removed by multiple centrifugation steps. Starting from 100 g of fresh leaf tissue, 2 - 3 mg of mitochondria can be routinely obtained. Respiratory experiments on these mitochondria display typical rates of 100 - 250 nmol O2 min-1 mg total mitochondrial protein-1 (NADH-dependent rate) with the ability to use various substrates and inhibitors to determine which substrates are being oxidized and the capacity of the alternative and cytochrome terminal oxidases. This protocol describes an isolation method of mitochondria from Arabidopsis thaliana leaves using continuous colloidal density gradients and an efficient respiratory measurements of purified plant mitochondria.
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Affiliation(s)
- Wenhui Lyu
- ARC Centre of Excellence in Plant Energy Biology, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University
| | - Jennifer Selinski
- ARC Centre of Excellence in Plant Energy Biology, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University;
| | - Lu Li
- ARC Centre of Excellence in Plant Energy Biology, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University
| | - David A Day
- School of Biological Sciences, Flinders University
| | - Monika W Murcha
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia
| | - James Whelan
- ARC Centre of Excellence in Plant Energy Biology, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University
| | - Yan Wang
- ARC Centre of Excellence in Plant Energy Biology, Department of Animal, Plant and Soil Science, School of Life Science, La Trobe University
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20
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Liu DYT, Smith PMC, Barton DA, Day DA, Overall RL. Characterisation of Arabidopsis calnexin 1 and calnexin 2 in the endoplasmic reticulum and at plasmodesmata. Protoplasma 2017; 254:125-136. [PMID: 26680228 DOI: 10.1007/s00709-015-0921-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 12/01/2015] [Indexed: 05/06/2023]
Abstract
Calnexin (CNX) is a highly conserved endoplasmic reticulum (ER) chaperone protein. Both calnexin and the homologous ER-lumenal protein, calreticulin, bind calcium ions and participate in protein folding. There are two calnexins in Arabidopsis thaliana, CNX1 and CNX2. GUS expression demonstrated that these are expressed in most Arabidopsis tissues throughout development. Calnexin transfer DNA (T-DNA) mutant lines exhibited increased transcript abundances of a number of other ER chaperones, including calreticulins, suggesting a degree of redundancy. CNX1 and CNX2 localised to the ER membrane including that within plasmodesmata, the intercellular channels connecting plant cells. This is comparable with the previous localisations of calreticulin in the ER lumen and at plasmodesmata. However, from green fluorescent protein (GFP) diffusion studies in single and double T-DNA insertion mutant lines, as well as overexpression lines, we found no evidence that CNX1 or CNX2 play a role in intercellular transport through plasmodesmata. In addition, calnexin T-DNA mutant lines showed no change in transcript abundance of a number of plasmodesmata-related proteins. CNX1 and CNX2 do not appear to have a specific localisation or function at plasmodesmata-rather the association of calnexin with the ER is simply maintained as the ER passes through plasmodesmata.
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Affiliation(s)
- Danny Y T Liu
- School of Biological Sciences, University of Sydney, Macleay Building A12, Sydney, NSW, 2006, Australia
- Learning and Teaching Centre, Macquarie University, Building C3B 417, Sydney, NSW, 2109, Australia
| | - Penelope M C Smith
- School of Biological Sciences, University of Sydney, Macleay Building A12, Sydney, NSW, 2006, Australia
| | - Deborah A Barton
- School of Biological Sciences, University of Sydney, Macleay Building A12, Sydney, NSW, 2006, Australia
| | - David A Day
- School of Biological Sciences, University of Sydney, Macleay Building A12, Sydney, NSW, 2006, Australia
- School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
| | - Robyn L Overall
- School of Biological Sciences, University of Sydney, Macleay Building A12, Sydney, NSW, 2006, Australia.
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21
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Marais EA, Jacob DJ, Jimenez JL, Campuzano-Jost P, Day DA, Hu W, Krechmer J, Zhu L, Kim PS, Miller CC, Fisher JA, Travis K, Yu K, Hanisco TF, Wolfe GM, Arkinson HL, Pye HOT, Froyd KD, Liao J, McNeill VF. Aqueous-phase mechanism for secondary organic aerosol formation from isoprene: application to the Southeast United States and co-benefit of SO 2 emission controls. Atmos Chem Phys 2016; 16:1603-1618. [PMID: 32742280 PMCID: PMC7394309 DOI: 10.5194/acp-16-1603-2016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Isoprene emitted by vegetation is an important precursor of secondary organic aerosol (SOA), but the mechanism and yields are uncertain. Aerosol is prevailingly aqueous under the humid conditions typical of isoprene-emitting regions. Here we develop an aqueous-phase mechanism for isoprene SOA formation coupled to a detailed gas-phase isoprene oxidation scheme. The mechanism is based on aerosol reactive uptake coefficients (γ) for water-soluble isoprene oxidation products, including sensitivity to aerosol acidity and nucleophile concentrations. We apply this mechanism to simulation of aircraft (SEAC4RS) and ground-based (SOAS) observations over the Southeast US in summer 2013 using the GEOS-Chem chemical transport model. Emissions of nitrogen oxides (NOx ≡ NO + NO2) over the Southeast US are such that the peroxy radicals produced from isoprene oxidation (ISOPO2) react significantly with both NO (high-NOx pathway) and HO2 (low-NOx pathway), leading to different suites of isoprene SOA precursors. We find a mean SOA mass yield of 3.3 % from isoprene oxidation, consistent with the observed relationship of total fine organic aerosol (OA) and formaldehyde (a product of isoprene oxidation). Isoprene SOA production is mainly contributed by two immediate gas-phase precursors, isoprene epoxydiols (IEPOX, 58% of isoprene SOA) from the low-NOx pathway and glyoxal (28%) from both low- and high-NOx pathways. This speciation is consistent with observations of IEPOX SOA from SOAS and SEAC4RS. Observations show a strong relationship between IEPOX SOA and sulfate aerosol that we explain as due to the effect of sulfate on aerosol acidity and volume. Isoprene SOA concentrations increase as NOx emissions decrease (favoring the low-NOx pathway for isoprene oxidation), but decrease more strongly as SO2 emissions decrease (due to the effect of sulfate on aerosol acidity and volume). The US EPA projects 2013-2025 decreases in anthropogenic emissions of 34% for NOx (leading to 7% increase in isoprene SOA) and 48% for SO2 (35% decrease in isoprene SOA). Reducing SO2 emissions decreases sulfate and isoprene SOA by a similar magnitude, representing a factor of 2 co-benefit for PM2.5 from SO2 emission controls.
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Affiliation(s)
- E A Marais
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - D J Jacob
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - J L Jimenez
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - P Campuzano-Jost
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - D A Day
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - W Hu
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - J Krechmer
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - L Zhu
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - P S Kim
- Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - C C Miller
- Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - J A Fisher
- School of Chemistry and School of Earth and Environmental Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - K Travis
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - K Yu
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - T F Hanisco
- Atmospheric Chemistry and Dynamics Lab, NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - G M Wolfe
- Atmospheric Chemistry and Dynamics Lab, NASA Goddard Space Flight Center, Greenbelt, MD, USA
- Joint Center for Earth Systems Technology, University of Maryland Baltimore County, Baltimore, MD, USA
| | - H L Arkinson
- Department of Atmospheric and Oceanic Science, University of Maryland, College Park, MD, USA
| | - H O T Pye
- National Exposure Research Laboratory, US EPA, Research Triangle Park, NC, USA
| | - K D Froyd
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Chemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA
| | - J Liao
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Chemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA
| | - V F McNeill
- Department of Chemical Engineering, Columbia University, New York, New York 10027, USA
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22
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Marais EA, Jacob DJ, Jimenez JL, Campuzano-Jost P, Day DA, Hu W, Krechmer J, Zhu L, Kim PS, Miller CC, Fisher JA, Travis K, Yu K, Hanisco TF, Wolfe GM, Arkinson HL, Pye HOT, Froyd KD, Liao J, McNeill VF. Aqueous-phase mechanism for secondary organic aerosol formation from isoprene: application to the Southeast United States and co-benefit of SO 2 emission controls. Atmos Chem Phys 2016. [PMID: 32742280 DOI: 10.5194/acp16-1603-2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Isoprene emitted by vegetation is an important precursor of secondary organic aerosol (SOA), but the mechanism and yields are uncertain. Aerosol is prevailingly aqueous under the humid conditions typical of isoprene-emitting regions. Here we develop an aqueous-phase mechanism for isoprene SOA formation coupled to a detailed gas-phase isoprene oxidation scheme. The mechanism is based on aerosol reactive uptake coefficients (γ) for water-soluble isoprene oxidation products, including sensitivity to aerosol acidity and nucleophile concentrations. We apply this mechanism to simulation of aircraft (SEAC4RS) and ground-based (SOAS) observations over the Southeast US in summer 2013 using the GEOS-Chem chemical transport model. Emissions of nitrogen oxides (NOx ≡ NO + NO2) over the Southeast US are such that the peroxy radicals produced from isoprene oxidation (ISOPO2) react significantly with both NO (high-NOx pathway) and HO2 (low-NOx pathway), leading to different suites of isoprene SOA precursors. We find a mean SOA mass yield of 3.3 % from isoprene oxidation, consistent with the observed relationship of total fine organic aerosol (OA) and formaldehyde (a product of isoprene oxidation). Isoprene SOA production is mainly contributed by two immediate gas-phase precursors, isoprene epoxydiols (IEPOX, 58% of isoprene SOA) from the low-NOx pathway and glyoxal (28%) from both low- and high-NOx pathways. This speciation is consistent with observations of IEPOX SOA from SOAS and SEAC4RS. Observations show a strong relationship between IEPOX SOA and sulfate aerosol that we explain as due to the effect of sulfate on aerosol acidity and volume. Isoprene SOA concentrations increase as NOx emissions decrease (favoring the low-NOx pathway for isoprene oxidation), but decrease more strongly as SO2 emissions decrease (due to the effect of sulfate on aerosol acidity and volume). The US EPA projects 2013-2025 decreases in anthropogenic emissions of 34% for NOx (leading to 7% increase in isoprene SOA) and 48% for SO2 (35% decrease in isoprene SOA). Reducing SO2 emissions decreases sulfate and isoprene SOA by a similar magnitude, representing a factor of 2 co-benefit for PM2.5 from SO2 emission controls.
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Affiliation(s)
- E A Marais
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - D J Jacob
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - J L Jimenez
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - P Campuzano-Jost
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - D A Day
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - W Hu
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - J Krechmer
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - L Zhu
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - P S Kim
- Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - C C Miller
- Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - J A Fisher
- School of Chemistry and School of Earth and Environmental Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - K Travis
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - K Yu
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - T F Hanisco
- Atmospheric Chemistry and Dynamics Lab, NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - G M Wolfe
- Atmospheric Chemistry and Dynamics Lab, NASA Goddard Space Flight Center, Greenbelt, MD, USA
- Joint Center for Earth Systems Technology, University of Maryland Baltimore County, Baltimore, MD, USA
| | - H L Arkinson
- Department of Atmospheric and Oceanic Science, University of Maryland, College Park, MD, USA
| | - H O T Pye
- National Exposure Research Laboratory, US EPA, Research Triangle Park, NC, USA
| | - K D Froyd
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Chemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA
| | - J Liao
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
- Chemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA
| | - V F McNeill
- Department of Chemical Engineering, Columbia University, New York, New York 10027, USA
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23
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Fisher JA, Jacob DJ, Travis KR, Kim PS, Marais EA, Miller CC, Yu K, Zhu L, Yantosca RM, Sulprizio MP, Mao J, Wennberg PO, Crounse JD, Teng AP, Nguyen TB, St Clair JM, Cohen RC, Romer P, Nault BA, Wooldridge PJ, Jimenez JL, Campuzano-Jost P, Day DA, Hu W, Shepson PB, Xiong F, Blake DR, Goldstein AH, Misztal PK, Hanisco TF, Wolfe GM, Ryerson TB, Wisthaler A, Mikoviny T. Organic nitrate chemistry and its implications for nitrogen budgets in an isoprene- and monoterpene-rich atmosphere: constraints from aircraft (SEAC 4RS) and ground-based (SOAS) observations in the Southeast US. Atmos Chem Phys 2016; 16:5969-5991. [PMID: 29681921 PMCID: PMC5906813 DOI: 10.5194/acp-16-5969-2016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Formation of organic nitrates (RONO2) during oxidation of biogenic volatile organic compounds (BVOCs: isoprene, monoterpenes) is a significant loss pathway for atmospheric nitrogen oxide radicals (NOx), but the chemistry of RONO2 formation and degradation remains uncertain. Here we implement a new BVOC oxidation mechanism (including updated isoprene chemistry, new monoterpene chemistry, and particle uptake of RONO2) in the GEOS-Chem global chemical transport model with ∼25 × 25 km2 resolution over North America. We evaluate the model using aircraft (SEAC4RS) and ground-based (SOAS) observations of NOx, BVOCs, and RONO2 from the Southeast US in summer 2013. The updated simulation successfully reproduces the concentrations of individual gas- and particle-phase RONO2 species measured during the campaigns. Gas-phase isoprene nitrates account for 25-50% of observed RONO2 in surface air, and we find that another 10% is contributed by gas-phase monoterpene nitrates. Observations in the free troposphere show an important contribution from long-lived nitrates derived from anthropogenic VOCs. During both campaigns, at least 10% of observed boundary layer RONO2 were in the particle phase. We find that aerosol uptake followed by hydrolysis to HNO3 accounts for 60% of simulated gas-phase RONO2 loss in the boundary layer. Other losses are 20% by photolysis to recycle NOx and 15% by dry deposition. RONO2 production accounts for 20% of the net regional NOx sink in the Southeast US in summer, limited by the spatial segregation between BVOC and NOx emissions. This segregation implies that RONO2 production will remain a minor sink for NOx in the Southeast US in the future even as NOx emissions continue to decline.
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Affiliation(s)
- J A Fisher
- Centre for Atmospheric Chemistry, School of Chemistry, University of Wollongong, Wollongong, NSW, Australia
- School of Earth and Environmental Sciences, University of Wollongong, Wollongong, NSW, Australia
| | - D J Jacob
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - K R Travis
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - P S Kim
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - E A Marais
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - C Chan Miller
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
| | - K Yu
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - L Zhu
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - R M Yantosca
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - M P Sulprizio
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - J Mao
- Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, NJ, USA
- Geophysical Fluid Dynamics Laboratory/National Oceanic and Atmospheric Administration, Princeton, NJ, USA
| | - P O Wennberg
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA, USA
| | - J D Crounse
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - A P Teng
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - T B Nguyen
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
- Now at Department of Environmental Toxicology, University of California at Davis, Davis, CA, USA
| | - J M St Clair
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
- Now at Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA and Joint Center for Earth Systems Technology, University of Maryland Baltimore County, Baltimore, MD, USA
| | - R C Cohen
- Department of Chemistry, University of California at Berkeley, Berkeley, CA, USA
- Department of Earth and Planetary Science, University of California at Berkeley, Berkeley, CA, USA
| | - P Romer
- Department of Chemistry, University of California at Berkeley, Berkeley, CA, USA
| | - B A Nault
- Department of Earth and Planetary Science, University of California at Berkeley, Berkeley, CA, USA
- Now at Department of Chemistry and Biochemistry and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - P J Wooldridge
- Department of Chemistry, University of California at Berkeley, Berkeley, CA, USA
| | - J L Jimenez
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - P Campuzano-Jost
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - D A Day
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - W Hu
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - P B Shepson
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
- Department of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, IN, USA
| | - F Xiong
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - D R Blake
- Department of Chemistry, University of California Irvine, Irvine, CA, USA
| | - A H Goldstein
- Department of Environmental Science, Policy, and Management, University of California at Berkeley, Berkeley, CA, USA
- Department of Civil and Environmental Engineering, University of California at Berkeley, Berkeley, CA, USA
| | - P K Misztal
- Department of Environmental Science, Policy, and Management, University of California at Berkeley, Berkeley, CA, USA
| | - T F Hanisco
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - G M Wolfe
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
- Joint Center for Earth Systems Technology, University of Maryland Baltimore County, Baltimore, MD, USA
| | - T B Ryerson
- Chemical Sciences Division, Earth System Research Lab, National Oceanic and Atmospheric Administration, Boulder, CO, USA
| | - A Wisthaler
- Department of Chemistry, University of Oslo, Oslo, Norway
- Institute for Ion Physics and Applied Physics, University of Innsbruck, Innsbruck, Austria
| | - T Mikoviny
- Department of Chemistry, University of Oslo, Oslo, Norway
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Clarke VC, Loughlin PC, Gavrin A, Chen C, Brear EM, Day DA, Smith PMC. Proteomic analysis of the soybean symbiosome identifies new symbiotic proteins. Mol Cell Proteomics 2015; 14:1301-22. [PMID: 25724908 PMCID: PMC4424401 DOI: 10.1074/mcp.m114.043166] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 02/25/2015] [Indexed: 12/21/2022] Open
Abstract
Legumes form a symbiosis with rhizobia in which the plant provides an energy source to the rhizobia bacteria that it uses to fix atmospheric nitrogen. This nitrogen is provided to the legume plant, allowing it to grow without the addition of nitrogen fertilizer. As part of the symbiosis, the bacteria in the infected cells of a new root organ, the nodule, are surrounded by a plant-derived membrane, the symbiosome membrane, which becomes the interface between the symbionts. Fractions containing the symbiosome membrane (SM) and material from the lumen of the symbiosome (peribacteroid space or PBS) were isolated from soybean root nodules and analyzed using nongel proteomic techniques. Bicarbonate stripping and chloroform-methanol extraction of isolated SM were used to reduce complexity of the samples and enrich for hydrophobic integral membrane proteins. One hundred and ninety-seven proteins were identified as components of the SM, with an additional fifteen proteins identified from peripheral membrane and PBS protein fractions. Proteins involved in a range of cellular processes such as metabolism, protein folding and degradation, membrane trafficking, and solute transport were identified. These included a number of proteins previously localized to the SM, such as aquaglyceroporin nodulin 26, sulfate transporters, remorin, and Rab7 homologs. Among the proteome were a number of putative transporters for compounds such as sulfate, calcium, hydrogen ions, peptide/dicarboxylate, and nitrate, as well as transporters for which the substrate is not easy to predict. Analysis of the promoter activity for six genes encoding putative SM proteins showed nodule specific expression, with five showing expression only in infected cells. Localization of two proteins was confirmed using GFP-fusion experiments. The data have been deposited to the ProteomeXchange with identifier PXD001132. This proteome will provide a rich resource for the study of the legume-rhizobium symbiosis.
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Affiliation(s)
- Victoria C Clarke
- From the ‡University of Sydney, School of Biological Sciences, Sydney Australia
| | - Patrick C Loughlin
- From the ‡University of Sydney, School of Biological Sciences, Sydney Australia
| | - Aleksandr Gavrin
- From the ‡University of Sydney, School of Biological Sciences, Sydney Australia
| | - Chi Chen
- From the ‡University of Sydney, School of Biological Sciences, Sydney Australia
| | - Ella M Brear
- From the ‡University of Sydney, School of Biological Sciences, Sydney Australia
| | - David A Day
- From the ‡University of Sydney, School of Biological Sciences, Sydney Australia; §Flinders University, School of Biological Sciences, Adelaide Australia
| | - Penelope M C Smith
- From the ‡University of Sydney, School of Biological Sciences, Sydney Australia;
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25
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Clarke VC, Loughlin PC, Day DA, Smith PMC. Transport processes of the legume symbiosome membrane. Front Plant Sci 2014; 5:699. [PMID: 25566274 PMCID: PMC4266029 DOI: 10.3389/fpls.2014.00699] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 11/24/2014] [Indexed: 05/19/2023]
Abstract
The symbiosome membrane (SM) is a physical barrier between the host plant and nitrogen-fixing bacteria in the legume:rhizobia symbiosis, and represents a regulated interface for the movement of solutes between the symbionts that is under plant control. The primary nutrient exchange across the SM is the transport of a carbon energy source from plant to bacteroid in exchange for fixed nitrogen. At a biochemical level two channels have been implicated in movement of fixed nitrogen across the SM and a uniporter that transports monovalent dicarboxylate ions has been characterized that would transport fixed carbon. The aquaporin NOD26 may provide a channel for ammonia, but the genes encoding the other transporters have not been identified. Transport of several other solutes, including calcium and potassium, have been demonstrated in isolated symbiosomes, and genes encoding transport systems for the movement of iron, nitrate, sulfate, and zinc in nodules have been identified. However, definitively matching transport activities with these genes has proved difficult and many further transport processes are expected on the SM to facilitate the movement of nutrients between the symbionts. Recently, work detailing the SM proteome in soybean has been completed, contributing significantly to the database of known SM proteins. This represents a valuable resource for the identification of transporter protein candidates, some of which may correspond to transport processes previously described, or to novel transport systems in the symbiosis. Putative transporters identified from the proteome include homologs of transporters of sulfate, calcium, peptides, and various metal ions. Here we review current knowledge of transport processes of the SM and discuss the requirements for additional transport routes of other nutrients exchanged in the symbiosis, with a focus on transport systems identified through the soybean SM proteome.
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Affiliation(s)
- Victoria C. Clarke
- School of Biological Sciences, University of Sydney, Sydney, NSW, Australia
| | | | - David A. Day
- School of Biological Sciences, Flinders University, Adelaide, SA, Australia
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26
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Cheah MH, Millar AH, Myers RC, Day DA, Roth J, Hillier W, Badger MR. Online oxygen kinetic isotope effects using membrane inlet mass spectrometry can differentiate between oxidases for mechanistic studies and calculation of their contributions to oxygen consumption in whole tissues. Anal Chem 2014; 86:5171-8. [PMID: 24786640 DOI: 10.1021/ac501086n] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The reduction chemistry of molecular oxygen underpins the energy metabolism of multicellular organisms, liberating free energy needed to catalyze a plethora of enzymatic reactions. Measuring the isotope signatures of (16)O and (18)O during O2 reduction can provide insights into both kinetic and equilibrium isotope effects. However, current methods to measure O2 isotope signatures are time-consuming and disruptive. This paper describes the application of membrane inlet mass spectrometry to determine the oxygen isotope discrimination of a range of O2-consuming reactions, providing a rapid and convenient method for determining these values. A survey of oxygenase and oxidase reactions provides new insights into previously uncharacterized amino acid oxidase enzymes. Liquid and gas phase measurements show the ease of assays using this approach for purified enzymes, biological extracts and intact tissues.
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Affiliation(s)
- Mun Hon Cheah
- Division of Plant Science, Research School of Biology, the Australian National University , Canberra ACT 0200, Australia
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27
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Chiasson DM, Loughlin PC, Mazurkiewicz D, Mohammadidehcheshmeh M, Fedorova EE, Okamoto M, McLean E, Glass ADM, Smith SE, Bisseling T, Tyerman SD, Day DA, Kaiser BN. Soybean SAT1 (Symbiotic Ammonium Transporter 1) encodes a bHLH transcription factor involved in nodule growth and NH4+ transport. Proc Natl Acad Sci U S A 2014; 111:4814-9. [PMID: 24707045 PMCID: PMC3977234 DOI: 10.1073/pnas.1312801111] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Glycine max symbiotic ammonium transporter 1 was first documented as a putative ammonium (NH4(+)) channel localized to the symbiosome membrane of soybean root nodules. We show that Glycine max symbiotic ammonium transporter 1 is actually a membrane-localized basic helix-loop-helix (bHLH) DNA-binding transcription factor now renamed Glycine max bHLH membrane 1 (GmbHLHm1). In yeast, GmbHLHm1 enters the nucleus and transcriptionally activates a unique plasma membrane NH4(+) channel Saccharomyces cerevisiae ammonium facilitator 1. Ammonium facilitator 1 homologs are present in soybean and other plant species, where they often share chromosomal microsynteny with bHLHm1 loci. GmbHLHm1 is important to the soybean rhizobium symbiosis because loss of activity results in a reduction of nodule fitness and growth. Transcriptional changes in nodules highlight downstream signaling pathways involving circadian clock regulation, nutrient transport, hormone signaling, and cell wall modification. Collectively, these results show that GmbHLHm1 influences nodule development and activity and is linked to a novel mechanism for NH4(+) transport common to both yeast and plants.
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Affiliation(s)
- David M. Chiasson
- School of Agriculture Food and Wine, The University of Adelaide, Adelaide, SA 5050, Australia
| | - Patrick C. Loughlin
- School of Agriculture Food and Wine, The University of Adelaide, Adelaide, SA 5050, Australia
- School of Biological Sciences, University of Sydney, Sydney, NSW 2006, Australia
| | - Danielle Mazurkiewicz
- School of Agriculture Food and Wine, The University of Adelaide, Adelaide, SA 5050, Australia
| | | | - Elena E. Fedorova
- Laboratory of Molecular Biology, Department of Plant Sciences, Wageningen University, 6703 HA, Wageningen, The Netherlands
| | - Mamoru Okamoto
- School of Agriculture Food and Wine, The University of Adelaide, Adelaide, SA 5050, Australia
| | - Elizabeth McLean
- School of Plant Biology, The University of Western Australia, Crawley, Perth, WA 6009, Australia
| | - Anthony D. M. Glass
- Department of Botany, The University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Sally E. Smith
- School of Agriculture Food and Wine, The University of Adelaide, Adelaide, SA 5050, Australia
| | - Ton Bisseling
- Laboratory of Molecular Biology, Department of Plant Sciences, Wageningen University, 6703 HA, Wageningen, The Netherlands
- College of Science, King Saud University, Riyadh 11451, Saudi Arabia; and
| | - Stephen D. Tyerman
- School of Agriculture Food and Wine, The University of Adelaide, Adelaide, SA 5050, Australia
| | - David A. Day
- School of Biological Sciences, Flinders University, Adelaide, SA 5001, Australia
| | - Brent N. Kaiser
- School of Agriculture Food and Wine, The University of Adelaide, Adelaide, SA 5050, Australia
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28
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Li R, Palm BB, Borbon A, Graus M, Warneke C, Ortega AM, Day DA, Brune WH, Jimenez JL, de Gouw JA. Laboratory studies on secondary organic aerosol formation from crude oil vapors. Environ Sci Technol 2013; 47:12566-12574. [PMID: 24088179 DOI: 10.1021/es402265y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Airborne measurements of aerosol composition and gas phase compounds over the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico in June 2010 indicated the presence of high concentrations of secondary organic aerosol (SOA) formed from organic compounds of intermediate volatility. In this work, we investigated SOA formation from South Louisiana crude oil vapors reacting with OH in a Potential Aerosol Mass flow reactor. We use the dependence of evaporation time on the saturation concentration (C*) of the SOA precursors to separate the contribution of species of different C* to total SOA formation. This study shows consistent results with those at the DWH oil spill: (1) organic compounds of intermediate volatility with C* = 10(5)-10(6) μg m(-3) contribute the large majority of SOA mass formed, and have much larger SOA yields (0.37 for C* = 10(5) and 0.21 for C* = 10(6) μg m(-3)) than more volatile compounds with C*≥10(7) μg m(-3), (2) the mass spectral signature of SOA formed from oxidation of the less volatile compounds in the reactor shows good agreement with that of SOA formed at DWH oil spill. These results also support the use of flow reactors simulating atmospheric SOA formation and aging.
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Affiliation(s)
- R Li
- Department of Atmospheric & Oceanic Sciences, University of Colorado , Boulder, Colorado 80309, United States
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29
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Brear EM, Day DA, Smith PMC. Iron: an essential micronutrient for the legume-rhizobium symbiosis. Front Plant Sci 2013; 4:359. [PMID: 24062758 PMCID: PMC3772312 DOI: 10.3389/fpls.2013.00359] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 08/26/2013] [Indexed: 05/19/2023]
Abstract
Legumes, which develop a symbiosis with nitrogen-fixing bacteria, have an increased demand for iron. Iron is required for the synthesis of iron-containing proteins in the host, including the highly abundant leghemoglobin, and in bacteroids for nitrogenase and cytochromes of the electron transport chain. Deficiencies in iron can affect initiation and development of the nodule. Within root cells, iron is chelated with organic acids such as citrate and nicotianamine and distributed to other parts of the plant. Transport to the nitrogen-fixing bacteroids in infected cells of nodules is more complicated. Formation of the symbiosis results in bacteroids internalized within root cortical cells of the legume where they are surrounded by a plant-derived membrane termed the symbiosome membrane (SM). This membrane forms an interface that regulates nutrient supply to the bacteroid. Consequently, iron must cross this membrane before being supplied to the bacteroid. Iron is transported across the SM as both ferric and ferrous iron. However, uptake of Fe(II) by both the symbiosome and bacteroid is faster than Fe(III) uptake. Members of more than one protein family may be responsible for Fe(II) transport across the SM. The only Fe(II) transporter in nodules characterized to date is GmDMT1 (Glycine max divalent metal transporter 1), which is located on the SM in soybean. Like the root plasma membrane, the SM has ferric iron reductase activity. The protein responsible has not been identified but is predicted to reduce ferric iron accumulated in the symbiosome space prior to uptake by the bacteroid. With the recent publication of a number of legume genomes including Medicago truncatula and G. max, a large number of additional candidate transport proteins have been identified. Members of the NRAMP (natural resistance-associated macrophage protein), YSL (yellow stripe-like), VIT (vacuolar iron transporter), and ZIP (Zrt-, Irt-like protein) transport families show enhanced expression in nodules and are expected to play a role in the transport of iron and other metals across symbiotic membranes.
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Affiliation(s)
- Ella M. Brear
- School of Biological Sciences, The University of SydneySydney, NSW, Australia
| | - David A. Day
- School of Biological Sciences, Flinders UniversityBedford Park, Adelaide, SA, Australia
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30
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Ng S, Giraud E, Duncan O, Law SR, Wang Y, Xu L, Narsai R, Carrie C, Walker H, Day DA, Blanco NE, Strand Å, Whelan J, Ivanova A. Cyclin-dependent kinase E1 (CDKE1) provides a cellular switch in plants between growth and stress responses. J Biol Chem 2012; 288:3449-59. [PMID: 23229550 DOI: 10.1074/jbc.m112.416727] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Plants must deal effectively with unfavorable growth conditions that necessitate a coordinated response to integrate cellular signals with mitochondrial retrograde signals. A genetic screen was carried out to identify regulators of alternative oxidase (rao mutants), using AOX1a expression as a model system to study retrograde signaling in plants. Two independent rao1 mutant alleles identified CDKE1 as a central nuclear component integrating mitochondrial retrograde signals with energy signals under stress. CDKE1 is also necessary for responses to general cellular stresses, such as H(2)O(2) and cold that act, at least in part, via anterograde pathways, and integrates signals from central energy/stress sensing kinase signal transduction pathways within the nucleus. Together, these results place CDKE1 as a central kinase integrating diverse cellular signals and shed light on a mechanism by which plants can effectively switch between growth and stress responses.
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Affiliation(s)
- Sophia Ng
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
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31
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Gandin A, Duffes C, Day DA, Cousins AB. The absence of alternative oxidase AOX1A results in altered response of photosynthetic carbon assimilation to increasing CO(2) in Arabidopsis thaliana. Plant Cell Physiol 2012; 53:1627-37. [PMID: 22848123 DOI: 10.1093/pcp/pcs107] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
In higher plants, the mitochondrial electron transport chain has non-phosphorylating alternative pathways that include the alternative terminal oxidase (AOX). This alternative pathway has been suggested to act as a sink for dissipating excess reducing power, minimizing oxidative stress and possibly optimizing photosynthesis in response to changing conditions. The expression patterns of the AOX genes have been well characterized under different growth conditions, particularly in response to light and temperature stress. Additionally, it has been suggested that mitochondrial electron transport is important for avoiding chloroplast over-reduction and balancing energy partitioning among photosynthesis, photorespiration and respiration. Nonetheless, the role AOX plays in optimizing photosynthetic carbon metabolism is unclear. Therefore, the response of photosynthesis to the disruption of AOX was investigated in the Arabidopsis thaliana T-DNA mutant aox1a (SALK_084897). Gas exchange analysis revealed a lower net CO(2) assimilation rate (A) at high CO(2) concentrations in the aox1a mutant compared to wild type. This decrease in A was accompanied by a lower maximum electron transport rate and quantum yield of PSII, and higher excitation pressure on PSII and non-photochemical quenching. The aox1a mutant also exhibited a lower estimated rate of ribulose 1,5-bisphosphate regeneration, and the ribulose 1,5-bisphosphate content was lower at high CO(2) concentrations, suggesting an ATP limitation of the Calvin-Benson cycle. Additionally, the activity of the malate-oxaloacetate shuttle was lower in the mutant compared to wild type. These results indicate that AOX is important for optimizing rates of photosynthetic CO(2) assimilation in response to rising CO(2) concentration by balancing the NAD(P)H/ATP ratio and rates of ribulose 1,5-bisphosphate regeneration within the chloroplast.
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Affiliation(s)
- Anthony Gandin
- School of Biological Sciences, Molecular Plant Science, Washington State University, Pullman, WA 99164-4236, USA
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32
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Chai TT, Simmonds D, Day DA, Colmer TD, Finnegan PM. A GmAOX2b antisense gene compromises vegetative growth and seed production in soybean. Planta 2012; 236:199-207. [PMID: 22307678 DOI: 10.1007/s00425-012-1601-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 01/20/2012] [Indexed: 05/21/2023]
Abstract
The alternative oxidase mediates the cyanide-resistant respiratory pathway in plant mitochondria. In non-thermogenic plants, the role of alternative oxidase in plant growth and development is not well understood. Soybean (Glycine max) lines carrying a GmAOX2b antisense gene had compromised vegetative growth and reproductive performance under typical glasshouse growth conditions. The reduction in vegetative growth was demonstrated by reduction in shoot height, the number of leaves per plant and the green leaf area. Antisense plants also had decreased pod formation and seed to pod ratios, which together led to a reduction in the number and total mass of seed produced. The negative effects of the antisense gene on pod set, seed set, ovule availability and total seed mass were primarily confined to the branches, rather than the main stem. The preferential effect of alternative oxidase suppression in the branches is discussed in relation to the reproductive potential of soybean under stress. Taken together, these results demonstrate that alternative oxidase provides the benefit of sustaining plant vegetative growth and reproductive capacity in soybean.
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Affiliation(s)
- Tsun-Thai Chai
- Faculty of Natural and Agricultural Sciences, School of Plant Biology and Institute of Agriculture, The University of Western Australia, Crawley, WA 6009, Australia
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33
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Abstract
Plasmodesmata are plasma membrane-lined channels through which cytoplasmic molecules move from cell-to-cell in plants. Most plasmodesmata contain a desmotubule, a central tube of endoplasmic reticulum (ER), that connects the ER of adjacent cells. Here we demonstrate that molecules of up to 10.4 kDa in size can move between the ER lumen of neighbouring leaf trichome or epidermal cells via the desmotubule lumen. Fluorescent molecules of up to 10 kDa, microinjected into the ER of Nicotiana trichome cells, consistently moved into the ER and nuclei of neighbouring trichome cells. This movement occurred more rapidly than movement via the cytoplasmic pathway. A fluorescent 3-kDa dextran microinjected into the ER of a basal trichome cell moved into the ER and nuclei of epidermal cells across a barrier to cytoplasmic movement. We constructed a 10.4-kDa recombinant ER-lumenal reporter protein (LRP) from a fragment of the endogenous ER-lumenal binding protein AtBIP1. Following transient expression of the LRP in the ER of Tradescantia leaf epidermal cells, it often moved into the nuclear envelopes of neighbouring cells. However, green fluorescent protein targeted to the ER lumen (ER-GFP) did not move from cell to cell. We propose that the ER lumen of plant cells is continuous with that of their neighbours, and allows movement of small ER-lumenal molecules between cells.
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Affiliation(s)
- Deborah A Barton
- School of Biological Sciences, Macleay Building A12, University of Sydney, NSW 2006, Australia
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34
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Abstract
Mitochondrial respiration in plants provides energy for biosynthesis, and its balance with photosynthesis determines the rate of plant biomass accumulation. We describe recent advances in our understanding of the mitochondrial respiratory machinery of cells, including the presence of a classical oxidative phosphorylation system linked to the cytosol by transporters, discussed alongside nonphosphorylating (and, therefore, non-energy conserving) bypasses that alter the efficiency of ATP synthesis and play a role in oxidative stress responses in plants. We consider respiratory regulation in the context of the contrasting roles mitochondria play in different tissues, from photosynthetic leaves to nutrient-acquiring roots. We focus on the molecular nature of this regulation at transcriptional and post-transcriptional levels that allow the respiratory apparatus of plants to help shape organ development and the response of plants to environmental stress. We highlight the challenges for future research considering spatial and temporal changes of respiration in response to changing climatic conditions.
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Affiliation(s)
- A Harvey Millar
- Australian Research Council Center of Excellence in Plant Energy Biology, University of Western Australia, M316 Crawley, Western Australia 6009, Australia
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35
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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 Physiol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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36
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Ho AYY, Day DA, Brown MH, Marc J. Arabidopsis phospholipase Dδ as an initiator of cytoskeleton-mediated signalling to fundamental cellular processes. Funct Plant Biol 2009; 36:190-198. [PMID: 32688638 DOI: 10.1071/fp08222] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Accepted: 12/10/2008] [Indexed: 06/11/2023]
Abstract
Phospholipase D (PLD), in combination with the cytoskeleton, plays a key role in plant signal transduction. One isotype of the multigene Arabidopsis PLD family, AtPLDδ, has been implicated in binding microtubules, although the molecular details of the mechanism and identities of potential interaction partners are unclear. We constructed a GFP-AtPLDδ reporter gene, stably transformed it into an Arabidopsis suspension cell line, and used epitope-tagged affinity pull-down assays to isolate a complex of co-purifying proteins. Mass spectrometry analysis of the complex revealed a set of proteins including β-tubulin, actin 7, HSP70, clathrin heavy chain, ATP synthase subunits, and a band 7-4/flotillin homologue. Sequence alignments with defined tubulin- and actin-binding regions from human HsPLD2 revealed highly homologous regions in all 12 AtPLD isotypes, suggesting direct interactions of AtPLDδ with tubulin and actin, while interactions with the remaining partners are likely to be mediated by the cytoskeleton. We propose that AtPLDδ acts through a complex of cytoskeletal and partner proteins to modulate fundamental cellular processes such as cytoskeletal rearrangements, vesicular trafficking, assembly of Golgi apparatus, mitosis and cytokinesis.
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Affiliation(s)
- Angela Y Y Ho
- School of Biological Sciences, Macleay Building A12, University of Sydney, Sydney, NSW 2006, Australia
| | - David A Day
- School of Biological Sciences, Macleay Building A12, University of Sydney, Sydney, NSW 2006, Australia
| | - Melissa H Brown
- School of Biological Sciences, Macleay Building A12, University of Sydney, Sydney, NSW 2006, Australia
| | - Jan Marc
- School of Biological Sciences, Macleay Building A12, University of Sydney, Sydney, NSW 2006, Australia
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Garmier M, Carroll AJ, Delannoy E, Vallet C, Day DA, Small ID, Millar AH. Complex I dysfunction redirects cellular and mitochondrial metabolism in Arabidopsis. Plant Physiol 2008; 148:1324-41. [PMID: 18784283 PMCID: PMC2577250 DOI: 10.1104/pp.108.125880] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2008] [Accepted: 09/05/2008] [Indexed: 05/19/2023]
Abstract
Mitochondrial complex I is a major avenue for reduced NAD oxidation linked to oxidative phosphorylation in plants. However, the plant enzyme has structural and functional features that set it apart from its counterparts in other organisms, raising questions about the physiological significance of this complex in plants. We have developed an experimental model in which rotenone, a classic complex I inhibitor, has been applied to Arabidopsis (Arabidopsis thaliana) cell suspension cultures in order to dissect early metabolic adjustments involved in cell acclimation to mitochondrial dysfunction. Rotenone induced a transitory decrease in cellular respiration (0-4 h after treatment). Cell respiration then progressively recovered and reached a steady state at 10 to 12 h after treatment. Complex I inhibition by rotenone did not induce obvious oxidative stress or cell death but affected longer term cell growth. Integrated analyses of gene expression, the mitochondrial proteome, and changes in primary metabolism indicated that rotenone treatment caused changes in mitochondrial function via alterations in specific components. A physical disengagement of glycolytic activities associated with the mitochondrial outer membrane was observed, and the tricarboxylic acid cycle was altered. Amino acid and organic acid pools were also modified by rotenone treatment, with a marked early decrease of 2-oxoglutarate, aspartate, and glutamine pools. These data demonstrate that, in Arabidopsis cells, complex I inhibition by rotenone induces significant remodeling of metabolic pathways involving the mitochondria and other compartments and point to early metabolic changes in response to mitochondrial dysfunction.
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Affiliation(s)
- Marie Garmier
- Australian Research Council Centre of Excellence in Plant Energy Biology M316, University of Western Australia, Crawley, Western Australia 6009, Australia
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38
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Armstrong AF, Badger MR, Day DA, Barthet MM, Smith PMC, Millar AH, Whelan J, Atkin OK. Dynamic changes in the mitochondrial electron transport chain underpinning cold acclimation of leaf respiration. Plant Cell Environ 2008; 31:1156-1169. [PMID: 18507806 DOI: 10.1111/j.1365-3040.2008.01830.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We examined the effect of short- and long-term changes in temperature on gene expression, protein abundance, and the activity of the alternative oxidase and cytochrome oxidase pathways (AOP and COP, respectively) in Arabidopsis thaliana. The AOP was more sensitive to short-term changes in temperature than the COP, with partitioning to the AOP decreasing significantly below a threshold temperature of 20 degrees C. AOP activity was increased in leaves, which had been shifted to the cold for several days, but this response was transient, with AOP activity subsiding (and COP activity increasing) following the development of leaves in the cold. The transient increase in AOP activity in 10-d cold-shifted leaves was not associated with an increase in alternative oxidase (AOX) protein or AOX1a transcript abundance. By contrast, the amount of uncoupling protein was significantly increased in cold-developed leaves. In conjunction with this, transcript levels of the uncoupling protein-encoding gene UCP1 and the external NAD(P)H dehydrogenase-encoding gene NDB2 exhibited sustained increases following growth in the cold. The data suggest a role for each of these alternative non-phosphorylating bypasses of mitochondrial electron transport at different points in time following exposure to cold, with increased AOP activity being important only in the early stages of cold treatment.
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Affiliation(s)
- Anna F Armstrong
- Department of Biology, University of York, PO Box 373, York, YO10 5YW, UK
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39
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Abstract
Mitochondria represent the powerhouse of cells through their synthesis of ATP. However, understanding the role of mitochondria in the growth and development of plants will rely on a much deeper appreciation of the complexity of this organelle. Arabidopsis research has provided clear identification of mitochondrial components, allowed wide-scale analysis of gene expression, and has aided reverse genetic manipulation to test the impact of mitochondrial component loss on plant function. Forward genetics in Arabidopsis has identified mitochondrial involvement in mutations with notable impacts on plant metabolism, growth and development. Here we consider the evidence for components involved in mitochondria biogenesis, metabolism and signalling to the nucleus.
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40
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Abstract
Mitochondria represent the powerhouse of cells through their synthesis of ATP. However, understanding the role of mitochondria in the growth and development of plants will rely on a much deeper appreciation of the complexity of this organelle. Arabidopsis research has provided clear identification of mitochondrial components, allowed wide-scale analysis of gene expression, and has aided reverse genetic manipulation to test the impact of mitochondrial component loss on plant function. Forward genetics in Arabidopsis has identified mitochondrial involvement in mutations with notable impacts on plant metabolism, growth and development. Here we consider the evidence for components involved in mitochondria biogenesis, metabolism and signalling to the nucleus.
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Affiliation(s)
- A. Harvey Millar
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009
| | - Ian D. Small
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009
| | - David A. Day
- School of Biological Sciences, The University of Sydney 2006, NSW, Australia
| | - James Whelan
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009
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Winger AM, Taylor NL, Heazlewood JL, Day DA, Millar AH. Identification of intra- and intermolecular disulphide bonding in the plant mitochondrial proteome by diagonal gel electrophoresis. Proteomics 2008; 7:4158-70. [PMID: 17994621 DOI: 10.1002/pmic.200700209] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Redox active proteins in plant mitochondria were examined using 2-D oxidant/reductant diagonal-SDS-PAGE to separate and identify proteins with intermolecular or intramolecular disulphide bonds using diamide in the first dimension and DTT in the second dimension. Eighteen proteins spots were resolved either above or below the diagonal and these were in-gel digested and identified by MS/MS. This analysis revealed intermolecular disulphide bonds in alternative oxidase, O-acetylserine (thiol) lyase, citrate synthase and between subunits of the ATP synthase. Intramolecular disulphide bonds were observed in a range of mitochondrial dehydrogenases, elongation factor Tu, adenylate kinase and the phosphate translocator. Many of the soluble proteins found were known glutaredoxin/thioredoxin targets in other plants, but the membrane proteins were not found by these methods nor were the nature of the disulphides able to be investigated. The accessibility of thiols involved in disulphide bonds to modification by a lipid derived aldehyde gave an insight into the potential impact of Cys modification on redox-functions in mitochondria during lipid peroxidation. Comparison of the protein sequences of the identified proteins with homologs from other species has identified specific Cys residues that may be responsible for plant-specific redox modulations of mitochondrial proteins.
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Affiliation(s)
- Alison M Winger
- ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, WA, Australia
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Winger AM, Taylor NL, Heazlewood JL, Day DA, Millar AH. The Cytotoxic lipid peroxidation product 4-hydroxy-2-nonenal covalently modifies a selective range of proteins linked to respiratory function in plant mitochondria. J Biol Chem 2007; 282:37436-47. [PMID: 17947244 DOI: 10.1074/jbc.m702385200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Plants encounter a variety of environmental stresses that affect their cellular machinery and that they adapt to on a daily basis. Lipid peroxidation is one consequence, at the cellular level, of such stresses and yields cytotoxic lipid aldehydes, including 4-hydroxy-2-nonenal (HNE), that react with specific sites in proteins, leading to diverse changes in protein function and/or stability. We have assessed the sensitivity of plant mitochondrial proteins to HNE modification, using one-dimensional and two-dimensional denaturing PAGE and blue native-PAGE coupled to immunological detection and tandem mass spectrometry identification. A select range of proteins was modified by exogenous application of HNE to mitochondria isolated from Arabidopsis cell cultures. These included a number of proteins that directly interact with the ubiquinone pool, as well as a number of soluble matrix proteins. Mitochondria isolated from cell cultures following hydrogen peroxide, antimycin A, or menadione treatment had significantly reduced respiratory capacity and elevated levels of HNE adduction to specific subsets of proteins. Targets identified included the proteins affected by direct application of HNE but also some new proteins, including a number of matrix dehydrogenases, the inner membrane adenine nucleotide translocator, and the outer membrane voltage-dependent anion channel. Degradation products of some proteins were also found to be HNE adducted, suggesting a link between HNE adduction and protein turnover. Some of the major enzyme complexes that were HNE adducted did not show demonstrable changes in their maximal activity measured with artificial acceptors, but changes did occur in associations between respiratory chain complexes following stress treatments.
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Affiliation(s)
- Alison M Winger
- Australian Research Council Centre of Excellence in Plant Energy Biology, the University of Western Australia, Crawley, Western Australia
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Ribas-Carbo M, Taylor NL, Giles L, Busquets S, Finnegan PM, Day DA, Lambers H, Medrano H, Berry JA, Flexas J. Effects of water stress on respiration in soybean leaves. Plant Physiol 2005; 139:466-73. [PMID: 16126857 PMCID: PMC1203395 DOI: 10.1104/pp.105.065565] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2005] [Revised: 06/20/2005] [Accepted: 06/20/2005] [Indexed: 05/04/2023]
Abstract
The effect of water stress on respiration and mitochondrial electron transport has been studied in soybean (Glycine max) leaves, using the oxygen-isotope-fractionation technique. Treatments with three levels of water stress were applied by irrigation to replace 100%, 50%, and 0% of daily water use by transpiration. The levels of water stress were characterized in terms of light-saturated stomatal conductance (g(s)): well irrigated (g(s) > 0.2 mol H(2)O m(-2) s(-1)), mildly water stressed (g(s) between 0.1 and 0.2 mol H(2)O m(-2) s(-1)), and severely water stressed (g(s) < 0.1 mol H(2)O m(-2) s(-1)). Although net photosynthesis decreased by 40% and 70% under mild and severe water stress, respectively, the total respiratory oxygen uptake (V(t)) was not significantly different at any water-stress level. However, severe water stress caused a significant shift of electrons from the cytochrome to the alternative pathway. The electron partitioning through the alternative pathway increased from 10% to 12% under well-watered or mild water-stress conditions to near 40% under severe water stress. Consequently, the calculated rate of mitochondrial ATP synthesis decreased by 32% under severe water stress. Unlike many other stresses, water stress did not affect the levels of mitochondrial alternative oxidase protein. This suggests a biochemical regulation (other than protein synthesis) that causes this mitochondrial electron shift.
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Affiliation(s)
- Miquel Ribas-Carbo
- Grup de Recerca en Biologia de les Plantes en Condicions Mediterrànies, Universitat de les Illes Balears, Spain.
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Abstract
Exposure to adverse environmental conditions causes oxidative stress in many organisms, leading either to disease and debilitation or to response and tolerance. Mitochondria are a key site of oxidative stress and of cellular response and play important roles in cell survival. We analyzed the response of mitochondria in pea (Pisum sativum) plants to the common stresses associated with drought, cold, and herbicides. These treatments all altered photosynthetic and respiratory rates of pea leaves to various extents, but only herbicides significantly increased lipid peroxidation product accumulation. Mitochondria isolated from the stressed pea plants maintained their electron transport chain activity, but changes were evident in the abundance of uncoupling proteins, non-phosphorylating respiratory pathways, and oxidative modification of lipoic acid moieties on mitochondrial proteins. These data suggest that herbicide treatment placed a severe oxidative stress on mitochondria, whereas chilling and particularly drought were milder stresses. Detailed analysis of the soluble proteome of mitochondria by gel electrophoresis and mass spectrometry revealed differential degradation of key matrix enzymes during treatments with chilling being significantly more damaging than drought. Differential induction of heat shock proteins and specific losses of other proteins illustrated the diversity of response to these stresses at the protein level. Cross-species matching was required for mass spectrometry identification of nine proteins because only a limited number of pea cDNAs have been sequenced, and the full pea genome is not available. Blue-native separation of intact respiratory chain complexes revealed little if any change in response to environmental stresses. Together these data suggest that although many of the molecular events identified by chemical stresses of mitochondria from a range of model eukaryotes are also apparent during environmental stress of plants, their extent and significance can vary substantially.
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Affiliation(s)
- Nicolas L Taylor
- The Plant Molecular Biology Group, Biochemistry and Molecular Biology, School of Biomedical and Chemical Sciences, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Western Australia, Australia
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Clifton R, Lister R, Parker KL, Sappl PG, Elhafez D, Millar AH, Day DA, Whelan J. Stress-induced co-expression of alternative respiratory chain components in Arabidopsis thaliana. Plant Mol Biol 2005; 58:193-212. [PMID: 16027974 DOI: 10.1007/sl] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/19/2005] [Accepted: 04/14/2005] [Indexed: 05/27/2023]
Abstract
Plant mitochondria contain non-phosphorylating bypasses of the respiratory chain, catalysed by the alternative oxidase (AOX) and alternative NADH dehydrogenases (NDH), as well as uncoupling (UCP) protein. Each of these components either circumvents or short-circuits proton translocation pathways, and each is encoded by a small gene family in Arabidopsis. Whole genome microarray experiments were performed with suspension cell cultures to examine the effects of various 3 h treatments designed to induce abiotic stress. The expression of over 60 genes encoding components of the classical, phosphorylating respiratory chain and tricarboxylic acid cycle remained largely constant when cells were subjected to a broad range of abiotic stresses, but expression of the alternative components responded differentially to the various treatments. In detailed time-course quantitative PCR analysis, specific members of both AOX and NDH gene families displayed coordinated responses to treatments. In particular, the co-expression of AOX1a and NDB2 observed under a number of treatments suggested co-regulation that may be directed by common sequence elements arranged hierarchically in the upstream promoter regions of these genes. A series of treatment sets were identified, representing the response of specific AOX and NDH genes to mitochondrial inhibition, plastid inhibition and abiotic stresses. These treatment sets emphasise the multiplicity of pathways affecting alternative electron transport components in plants.
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Affiliation(s)
- Rachel Clifton
- Plant Molecular Biology Group, School of Biomedical and Chemical Sciences, The University of Western Australia, Crawley, Western Australia, Australia
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47
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Clifton R, Lister R, Parker KL, Sappl PG, Elhafez D, Millar AH, Day DA, Whelan J. Stress-induced co-expression of alternative respiratory chain components in Arabidopsis thaliana. Plant Mol Biol 2005; 58:193-212. [PMID: 16027974 DOI: 10.1007/s11103-005-5514-7] [Citation(s) in RCA: 218] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2005] [Accepted: 04/14/2005] [Indexed: 05/03/2023]
Abstract
Plant mitochondria contain non-phosphorylating bypasses of the respiratory chain, catalysed by the alternative oxidase (AOX) and alternative NADH dehydrogenases (NDH), as well as uncoupling (UCP) protein. Each of these components either circumvents or short-circuits proton translocation pathways, and each is encoded by a small gene family in Arabidopsis. Whole genome microarray experiments were performed with suspension cell cultures to examine the effects of various 3 h treatments designed to induce abiotic stress. The expression of over 60 genes encoding components of the classical, phosphorylating respiratory chain and tricarboxylic acid cycle remained largely constant when cells were subjected to a broad range of abiotic stresses, but expression of the alternative components responded differentially to the various treatments. In detailed time-course quantitative PCR analysis, specific members of both AOX and NDH gene families displayed coordinated responses to treatments. In particular, the co-expression of AOX1a and NDB2 observed under a number of treatments suggested co-regulation that may be directed by common sequence elements arranged hierarchically in the upstream promoter regions of these genes. A series of treatment sets were identified, representing the response of specific AOX and NDH genes to mitochondrial inhibition, plastid inhibition and abiotic stresses. These treatment sets emphasise the multiplicity of pathways affecting alternative electron transport components in plants.
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Affiliation(s)
- Rachel Clifton
- Plant Molecular Biology Group, School of Biomedical and Chemical Sciences, The University of Western Australia, Crawley, Western Australia, Australia
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48
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Barnard PJ, Baker MV, Berners-Price SJ, Day DA. Mitochondrial permeability transition induced by dinuclear gold(I)–carbene complexes: potential new antimitochondrial antitumour agents. J Inorg Biochem 2004; 98:1642-7. [PMID: 15458827 DOI: 10.1016/j.jinorgbio.2004.05.011] [Citation(s) in RCA: 193] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Revised: 05/22/2004] [Accepted: 05/27/2004] [Indexed: 11/23/2022]
Abstract
Seven dinuclear gold(I) complexes of bidentate N-heterocyclic carbene ligands have been evaluated for their ability to induce mitochondrial membrane permeabilisation (MMP) in isolated rat liver mitochondria. Six of the compounds, at concentrations of 10 microM, induced Ca(2+)-sensitive MMP as evidenced by mitochondrial swelling. In the absence of low concentrations of exogenous Ca(2+), the compounds were either inactive or their activity was significantly decreased. The mitochondrial swelling was completely blocked by the addition of cyclosporin A, a well established inhibitor of the mitochondrial permeability transition pore (MPT) that is believed to be responsible for MMP. The rates and levels of uptake of these compounds into mitochondria were estimated by measuring mitochondrial Au levels using inductively coupled plasma optical emission spectroscopy. Significant differences were found in the levels at which the different compounds accumulated in the mitochondria, but these differences did not correlate with the rate at which they induced mitochondrial swelling. These results suggest that the mechanism by which MMP is induced by these lipophilic cationic Au(I)-carbene complexes is not purely a function of the level of compound accumulation. Instead, a more specific mechanism, possibly involving disruption of the function of a particular enzyme, or interaction with a MPT component, appears to be more likely.
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Affiliation(s)
- Peter J Barnard
- Department of Chemistry, School of Biomedical and Chemical Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth 6009, Australia
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Kurimoto K, Millar AH, Lambers H, Day DA, Noguchi K. Maintenance of growth rate at low temperature in rice and wheat cultivars with a high degree of respiratory homeostasis is associated with a high efficiency of respiratory ATP production. Plant Cell Physiol 2004; 45:1015-22. [PMID: 15356327 DOI: 10.1093/pcp/pch116] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Some plants have the ability to maintain similar respiratory rates (measured at the growth temperature) when grown at different temperatures. This phenomenon is referred to as respiratory homeostasis. Using wheat and rice cultivars with different degrees of respiratory homeostasis (H), we previously demonstrated that high-H cultivars maintained shoot and root growth at low temperature [Kurimoto et al. (2004) Plant Cell Environ., 27: 853]. Here, we assess the relationship between respiratory homeostasis and the efficiency of respiratory ATP production, by measuring the levels of alternative oxidase (AOX) and uncoupling protein (UCP), which have the potential to decrease respiratory ATP production per unit of oxygen consumed. We also measured SHAM- and CN-resistant respiration of intact roots, and the capacity of the cytochrome pathway (CP) and AOX in isolated mitochondria. Irrespective of H, SHAM-resistant respiration of intact roots and CP capacity of isolated root mitochondria were larger when plants were grown at low temperature, and the maximal activity and relative amounts of cytochrome c oxidase showed a similar trend. In contrast, CN-resistant respiration of intact roots and relative amounts of AOX protein in mitochondria isolated from those roots, were lower in high-H plants grown at low temperature. In the roots of low-H cultivars, relative amounts of AOX protein were higher at low growth temperature. Relative amounts of UCP protein showed similar trends to AOX. We conclude that maintenance of growth rate in high-H plants grown at low temperature is associated with both respiratory homeostasis and a high efficiency of respiratory ATP production.
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Affiliation(s)
- Kohei Kurimoto
- Department of Biology, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka, 560-0043 Japan
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Shane MW, Cramer MD, Funayama-Noguchi S, Cawthray GR, Millar AH, Day DA, Lambers H. Developmental physiology of cluster-root carboxylate synthesis and exudation in harsh hakea. Expression of phosphoenolpyruvate carboxylase and the alternative oxidase. Plant Physiol 2004; 135:549-60. [PMID: 15122030 PMCID: PMC429412 DOI: 10.1104/pp.103.035659] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2003] [Revised: 02/16/2004] [Accepted: 02/22/2004] [Indexed: 05/18/2023]
Abstract
Harsh hakea (Hakea prostrata R.Br.) is a member of the Proteaceae family, which is highly represented on the extremely nutrient-impoverished soils in southwest Australia. When phosphorus is limiting, harsh hakea develops proteoid or cluster roots that release carboxylates that mobilize sparingly soluble phosphate in the rhizosphere. To investigate the physiology underlying the synthesis and exudation of carboxylates from cluster roots in Proteaceae, we measured O2 consumption, CO2 release, internal carboxylate concentrations and carboxylate exudation, and the abundance of the enzymes phosphoenolpyruvate carboxylase and alternative oxidase (AOX) over a 3-week time course of cluster-root development. Peak rates of citrate and malate exudation were observed from 12- to 13-d-old cluster roots, preceded by a reduction in cluster-root total protein levels and a reduced rate of O2 consumption. In harsh hakea, phosphoenolpyruvate carboxylase expression was relatively constant in cluster roots, regardless of developmental stage. During cluster-root maturation, however, the expression of AOX protein increased prior to the time when citrate and malate exudation peaked. This increase in AOX protein levels is presumably needed to allow a greater flow of electrons through the mitochondrial electron transport chain in the absence of rapid ATP turnover. Citrate and isocitrate synthesis and accumulation contributed in a major way to the subsequent burst of citrate and malate exudation. Phosphorus accumulated by harsh hakea cluster roots was remobilized during senescence as part of their efficient P cycling strategy for growth on nutrient impoverished soils.
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Affiliation(s)
- Michael W Shane
- School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, Crawley, Australia.
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