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Wang W, Du J, Chen L, Zeng Y, Tan X, Shi Q, Pan X, Wu Z, Zeng Y. Transcriptomic, proteomic, and physiological comparative analyses of flooding mitigation of the damage induced by low-temperature stress in direct seeded early indica rice at the seedling stage. BMC Genomics 2021; 22:176. [PMID: 33706696 PMCID: PMC7952222 DOI: 10.1186/s12864-021-07458-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 02/19/2021] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Low temperature (LT) often occurs at the seedling stage in the early rice-growing season, especially for direct seeded early-season indica rice, and using flooding irrigation can mitigate LT damage in rice seedlings. The molecular mechanism by which flooding mitigates the damage induced by LT stress has not been fully elucidated. Thus, LT stress at 8 °C, LT accompanied by flooding (LTF) and CK (control) treatments were established for 3 days to determine the transcriptomic, proteomic and physiological response in direct seeded rice seedlings at the seedling stage. RESULTS LT damaged chloroplasts, and thylakoid lamellae, and increased osmiophilic bodies and starch grains compared to CK, but LTF alleviated the damage to chloroplast structure caused by LT. The physiological characteristics of treated plants showed that compared with LT, LTF significantly increased the contents of rubisco, chlorophyll, PEPCK, ATP and GA3 but significantly decreased soluble protein, MDA and ABA contents. 4D-label-free quantitative proteomic profiling showed that photosynthesis-responsive proteins, such as phytochrome, as well as chlorophyll and the tricarboxylic acid cycle were significantly downregulated in LT/CK and LTF/CK comparison groups. However, compared with LT, phytochrome, chlorophyllide oxygenase activity and the glucan branching enzyme in LTF were significantly upregulated in rice leaves. Transcriptomic and proteomic studies identified 72,818 transcripts and 5639 proteins, and 4983 genes that were identified at both the transcriptome and proteome levels. Differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) were significantly enriched in glycine, serine and threonine metabolism, biosynthesis of secondary metabolites, glycolysis/gluconeogenesis and metabolic pathways. CONCLUSION Through transcriptomic, proteomic and physiological analyses, we determined that a variety of metabolic pathway changes were induced by LT and LTF. GO and KEGG enrichment analyses demonstrated that DEGs and DEPs were associated with photosynthesis pathways, antioxidant enzymes and energy metabolism pathway-related proteins. Our study provided new insights for efforts to reduce the damage to direct seeded rice caused by low-temperature stress and provided a breeding target for low temperature flooding-resistant cultivars. Further analysis of translational regulation and metabolites may help to elucidate the molecular mechanisms by which flooding mitigates low-temperature stress in direct seeded early indica rice at the seedling stage.
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Affiliation(s)
- Wenxia Wang
- Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education / Collaborative Innovation Center for the Modernization Production of Double Cropping Rice / College of Agronomy, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Jie Du
- Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education / Collaborative Innovation Center for the Modernization Production of Double Cropping Rice / College of Agronomy, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Liming Chen
- Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education / Collaborative Innovation Center for the Modernization Production of Double Cropping Rice / College of Agronomy, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Yongjun Zeng
- Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education / Collaborative Innovation Center for the Modernization Production of Double Cropping Rice / College of Agronomy, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Xueming Tan
- Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education / Collaborative Innovation Center for the Modernization Production of Double Cropping Rice / College of Agronomy, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Qinghua Shi
- Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education / Collaborative Innovation Center for the Modernization Production of Double Cropping Rice / College of Agronomy, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Xiaohua Pan
- Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education / Collaborative Innovation Center for the Modernization Production of Double Cropping Rice / College of Agronomy, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Ziming Wu
- Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education / Collaborative Innovation Center for the Modernization Production of Double Cropping Rice / College of Agronomy, Jiangxi Agricultural University, Nanchang, 330045, China.
| | - Yanhua Zeng
- Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education / Collaborative Innovation Center for the Modernization Production of Double Cropping Rice / College of Agronomy, Jiangxi Agricultural University, Nanchang, 330045, China.
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Liu J, Wang X, Yang L, Nan W, Ruan M, Bi Y. Involvement of active MKK9-MAPK3/MAPK6 in increasing respiration in salt-treated Arabidopsis callus. PROTOPLASMA 2020; 257:965-977. [PMID: 32008084 DOI: 10.1007/s00709-020-01483-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 01/20/2020] [Indexed: 06/10/2023]
Abstract
Mitogen-activated protein kinase kinase 9 (MKK9) is an upstream activator of mitogen-activated protein kinase 3 (MAPK3) and MAPK6 in planta. To investigate MKK9 roles in mitochondrial respiration in Arabidopsis, MKK9DD, the active allele with mutations of Thr-201 and Ser-205 to Asp, and MKK9KR, the allele lacking MKK9 activity with a mutation of Lys-76 to Arg, were used. Results showed that the total respiratory rate (Vt), alternative pathway capacity (Valt) and cytochrome pathway capacity (Vcyt) increased under 0-100 mM NaCl treatments but decreased under 150-300 mM NaCl treatments in Col-0 callus. However, the activation of MKK9 by dexamethasone (DEX) increased Vt, Valt and Vcyt under 200 mM NaCl treatment; moreover, Valt showed more increase than Vcyt. The activation of MKK9 in MKK9DD callus sharply increased AOX protein expression under normal and NaCl conditions, but the increase was not observed in MKK9KR callus. Further results indicated that MAPK3 and MAPK6 were involved in the MKK9-induced increase of AOX protein levels. qRT-PCR results showed that MKK9-MAPK3/MAPK6 was involved in the NaCl-induced AOX1b and AOX1d expression, but only MKK9-MAPK3 was necessary for AOX2 expression; in addition, MAPK3 regulated the AOX1a transcription in an MKK9-independent manner. MKK9 positively regulated SOD and CAT activities by affecting MAPK3 and MAPK6 and negatively regulated APX and POD activities by affecting MAPK3. Moreover, MKK9 functions as a positive factor in H2O2 accumulation under salt stress. The regulation of ethylene on alternative respiration was also associated with MKK9 under salt stress. Taken together, the MKK9-MAPK3/MAPK6 pathway plays a pivotal role in increasing alternative respiration in the salt-treated Arabidopsis callus.
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Affiliation(s)
- Jie Liu
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China
- Key Laboratory of Plant Physiology and Developmental Regulation, Guizhou Normal University, Guiyang, 550025, Guizhou, People's Republic of China
| | - Xiaomin Wang
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China.
| | - Lei Yang
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China
| | - Wenbin Nan
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China
| | - Mengjiao Ruan
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China
| | - Yurong Bi
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China.
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Del-Saz NF, Ribas-Carbo M, McDonald AE, Lambers H, Fernie AR, Florez-Sarasa I. An In Vivo Perspective of the Role(s) of the Alternative Oxidase Pathway. TRENDS IN PLANT SCIENCE 2018; 23:206-219. [PMID: 29269217 DOI: 10.1016/j.tplants.2017.11.006] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 10/18/2017] [Accepted: 11/15/2017] [Indexed: 05/02/2023]
Abstract
Despite intense research on the in vitro characterization of regulatory factors modulating the alternative oxidase (AOX) pathway, the regulation of its activity in vivo is still not fully understood. Advances concerning in vivo regulation of AOX based on the oxygen-isotope fractionation technique are reviewed, and regulatory factors that merit future research are highlighted. In addition, we review and discuss the main biological functions assigned to the plant AOX, and suggest future experiments involving in vivo activity measurements to test different hypothesized physiological roles.
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Affiliation(s)
- Néstor Fernández Del-Saz
- Grup de Recerca en Biologia de les Plantes en Condicions Mediterranies, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Spain
| | - Miquel Ribas-Carbo
- Grup de Recerca en Biologia de les Plantes en Condicions Mediterranies, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Spain
| | - Allison E McDonald
- Department of Biology, Wilfrid Laurier University, Science Building, 75 University Avenue West, Waterloo, ON N2L 3C5, Canada
| | - Hans Lambers
- School of Biological Sciences, University of Western Australia, 35 Stirling Highway, Crawley (Perth), Western Australia 6009, Australia
| | - Alisdair R Fernie
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Igor Florez-Sarasa
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany.
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Huang G, Zhang Q, Wei X, Peng S, Li Y. Nitrogen Can Alleviate the Inhibition of Photosynthesis Caused by High Temperature Stress under Both Steady-State and Flecked Irradiance. FRONTIERS IN PLANT SCIENCE 2017; 8:945. [PMID: 28634485 PMCID: PMC5459896 DOI: 10.3389/fpls.2017.00945] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 05/22/2017] [Indexed: 05/05/2023]
Abstract
Nitrogen is one of the most important elements for plants and is closely related to photosynthesis. High temperature stress significantly inhibits photosynthesis under both steady-state and flecked irradiance. However, it is not known whether nitrogen can affect the decrease in photosynthesis caused by high temperature, especially under flecked irradiance. In the present study, a pot experiment was conducted under two nitrogen (N) supplies with rice plants, and the steady-state and dynamic photosynthesis rates were measured under 28 and 40°C. High temperature significantly increased leaf hydraulic conductance (Kleaf) under high N supply (HN) but not under low N supply (LN). The increased Kleaf maintained a constant leaf water potential (Ψleaf) and steady-state stomatal conductance (gs,sat) under HN, while the Ψleaf and gs,sat significantly decreased under high temperature in LN conditions. This resulted in a more severe decrease in steady-state photosynthesis (Asat) under high temperature in the LN conditions. After shifting from low to high light, high temperature significantly delayed the recovery of photosynthesis, which resulted in more carbon loss under flecked irradiance. These effects were obtained under HN to a lesser extent than under LN supply. Therefore, it is concluded that nitrogen can alleviate the inhibition of photosynthesis caused by high temperature stress under both steady-state and flecked irradiance.
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Affiliation(s)
| | | | | | | | - Yong Li
- Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural UniversityWuhan, China
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Busch FA, Sage RF. The sensitivity of photosynthesis to O 2 and CO 2 concentration identifies strong Rubisco control above the thermal optimum. THE NEW PHYTOLOGIST 2017; 213:1036-1051. [PMID: 27768823 DOI: 10.1111/nph.14258] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 09/10/2016] [Indexed: 05/12/2023]
Abstract
The biochemical model of C3 photosynthesis by Farquhar, von Caemmerer and Berry (FvCB) assumes that photosynthetic CO2 assimilation is limited by one of three biochemical processes that are not always easily discerned. This leads to improper assessments of biochemical limitations that limit the accuracy of the model predictions. We use the sensitivity of rates of CO2 assimilation and photosynthetic electron transport to changes in O2 and CO2 concentration in the chloroplast to evaluate photosynthetic limitations. Assessing the sensitivities to O2 and CO2 concentrations reduces the impact of uncertainties in the fixed parameters to a minimum and simultaneously entirely eliminates the need to determine the variable parameters of the model, such as Vcmax , J, or TP . Our analyses demonstrate that Rubisco limits carbon assimilation at high temperatures, while it is limited by triose phosphate utilization at lower temperatures and at higher CO2 concentrations. Measurements can be assigned a priori to one of the three functions of the FvCB model, allowing testing for the suitability of the selected fixed parameters of the model. This approach can improve the reliability of photosynthesis models on scales from the leaf level to estimating the global carbon budget.
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Affiliation(s)
- Florian A Busch
- Plant Science Division, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
- Department of Ecology and Evolutionary Biology, The University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, The University of Toronto, Toronto, ON, M5S 3B2, Canada
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Zhang ZS, Liu MJ, Scheibe R, Selinski J, Zhang LT, Yang C, Meng XL, Gao HY. Contribution of the Alternative Respiratory Pathway to PSII Photoprotection in C3 and C4 Plants. MOLECULAR PLANT 2017; 10:131-142. [PMID: 27746301 DOI: 10.1016/j.molp.2016.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 09/29/2016] [Accepted: 10/05/2016] [Indexed: 05/02/2023]
Abstract
The mechanism by which the mitochondrial alternative oxidase (AOX) pathway contributes to photosystem II (PSII) photoprotection is in dispute. It was generally thought that the AOX pathway protects photosystems by dissipating excess reducing equivalents exported from chloroplasts through the malate/oxaloacetate (Mal/OAA) shuttle and thus preventing the over-reduction of chloroplasts. In this study, using the aox1a Arabidopsis mutant and nine other C3 and C4 plant species, we revealed an additional action model of the AOX pathway in PSII photoprotection. Although the AOX pathway contributes to PSII photoprotection in C3 leaves treated with high light, this contribution was observed to disappear when photorespiration was suppressed. Disruption or inhibition of the AOX pathway significantly decreased the photorespiration in C3 leaves. Moreover, the AOX pathway did not respond to high light and contributed little to PSII photoprotection in C4 leaves possessing a highly active Mal/OAA shuttle but with little photorespiration. These results demonstrate that the AOX pathway contributes to PSII photoprotection in C3 plants by maintaining photorespiration to detoxify glycolate and via the indirect export of excess reducing equivalents from chloroplasts by the Mal/OAA shuttle. This new action model explains why the AOX pathway does not contribute to PSII photoprotection in C4 plants.
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Affiliation(s)
- Zi-Shan Zhang
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, China; College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China; College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an 271018, China
| | - Mei-Jun Liu
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, China; College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Renate Scheibe
- Department of Plant Physiology, FB5, University of Osnabrueck, 49069 Osnabrueck, Germany
| | - Jennifer Selinski
- Department of Plant Physiology, FB5, University of Osnabrueck, 49069 Osnabrueck, Germany
| | - Li-Tao Zhang
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, China; College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China; National and Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China
| | - Cheng Yang
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, China; College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China; Wheat Research Institute, Henan Academy of Agricultural Sciences, Zhengzhou, Henan 450002, China
| | - Xiang-Long Meng
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, China; College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Hui-Yuan Gao
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, China; College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China.
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Bellasio C, Beerling DJ, Griffiths H. An Excel tool for deriving key photosynthetic parameters from combined gas exchange and chlorophyll fluorescence: theory and practice. PLANT, CELL & ENVIRONMENT 2016; 39:1180-97. [PMID: 25923517 DOI: 10.1111/pce.12560] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/10/2015] [Accepted: 02/25/2015] [Indexed: 05/23/2023]
Abstract
Combined photosynthetic gas exchange and modulated fluorometres are widely used to evaluate physiological characteristics associated with phenotypic and genotypic variation, whether in response to genetic manipulation or resource limitation in natural vegetation or crops. After describing relatively simple experimental procedures, we present the theoretical background to the derivation of photosynthetic parameters, and provide a freely available Excel-based fitting tool (EFT) that will be of use to specialists and non-specialists alike. We use data acquired in concurrent variable fluorescence-gas exchange experiments, where A/Ci and light-response curves have been measured under ambient and low oxygen. From these data, the EFT derives light respiration, initial PSII (photosystem II) photochemical yield, initial quantum yield for CO2 fixation, fraction of incident light harvested by PSII, initial quantum yield for electron transport, electron transport rate, rate of photorespiration, stomatal limitation, Rubisco (ribulose 1·5-bisphosphate carboxylase/oxygenase) rate of carboxylation and oxygenation, Rubisco specificity factor, mesophyll conductance to CO2 diffusion, light and CO2 compensation point, Rubisco apparent Michaelis-Menten constant, and Rubisco CO2 -saturated carboxylation rate. As an example, a complete analysis of gas exchange data on tobacco plants is provided. We also discuss potential measurement problems and pitfalls, and suggest how such empirical data could subsequently be used to parameterize predictive photosynthetic models.
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Affiliation(s)
- Chandra Bellasio
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - David J Beerling
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Howard Griffiths
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK
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Schlüter U, Weber APM. The Road to C4 Photosynthesis: Evolution of a Complex Trait via Intermediary States. PLANT & CELL PHYSIOLOGY 2016; 57:881-9. [PMID: 26893471 DOI: 10.1093/pcp/pcw009] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 01/05/2016] [Indexed: 05/09/2023]
Abstract
C4 photosynthesis enables high photosynthetic energy conversion efficiency as well as high nitrogen and water use efficiencies. Given the multitude of biochemical, structural and molecular changes in comparison with C3 photosynthesis, it appears unlikely that such a complex trait would evolve in a single step. C4 photosynthesis is therefore believed to have evolved from the ancestral C3 state via intermediary stages. Consequently, the identification and detailed characterization of plant species representing transitory states between C3 and C4 is important for the reconstruction of the sequence of evolutionary events, especially since C4 evolution occurred in very different phylogenetic backgrounds. There is also significant interest in engineering of C4 or at least C4-like elements into C3 crop plants. A detailed and mechanistic understanding of C3-C4 intermediates is likely to provide guidance for the experimental design of such approaches. Here we provide an overview on the most relevant results obtained on C3-C4 intermediates to date. Recent knowledge gains in this field will be described in more detail. We thereby concentrate especially on biochemical and physiological work. Finally, we will provide a perspective and outlook on the continued importance of research on C3-C4 intermediates.
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Affiliation(s)
- Urte Schlüter
- Institute of Plant Biochemistry and Cluster of Excellence on Plant Science (CEPLAS), Heinrich-Heine-University, Universitätsstrasse 1, D-40225 Düsseldorf, Germany
| | - Andreas P M Weber
- Institute of Plant Biochemistry and Cluster of Excellence on Plant Science (CEPLAS), Heinrich-Heine-University, Universitätsstrasse 1, D-40225 Düsseldorf, Germany
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Dinakar C, Vishwakarma A, Raghavendra AS, Padmasree K. Alternative Oxidase Pathway Optimizes Photosynthesis During Osmotic and Temperature Stress by Regulating Cellular ROS, Malate Valve and Antioxidative Systems. FRONTIERS IN PLANT SCIENCE 2016; 7:68. [PMID: 26904045 PMCID: PMC4747084 DOI: 10.3389/fpls.2016.00068] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Accepted: 01/15/2016] [Indexed: 05/19/2023]
Abstract
The present study reveals the importance of alternative oxidase (AOX) pathway in optimizing photosynthesis under osmotic and temperature stress conditions in the mesophyll protoplasts of Pisum sativum. The responses of photosynthesis and respiration were monitored at saturating light intensity of 1000 μmoles m(-2) s(-1) at 25°C under a range of sorbitol concentrations from 0.4 to 1.0 M to induce hyper-osmotic stress and by varying the temperature of the thermo-jacketed pre-incubation chamber from 25 to 10°C to impose sub-optimal temperature stress. Compared to controls (0.4 M sorbitol and 25°C), the mesophyll protoplasts showed remarkable decrease in NaHCO3-dependent O2 evolution (indicator of photosynthetic carbon assimilation), under both hyper-osmotic (1.0 M sorbitol) and sub-optimal temperature stress conditions (10°C), while the decrease in rates of respiratory O2 uptake were marginal. The capacity of AOX pathway increased significantly in parallel to increase in intracellular pyruvate and reactive oxygen species (ROS) levels under both hyper-osmotic stress and sub-optimal temperature stress under the background of saturating light. The ratio of redox couple (Malate/OAA) related to malate valve increased in contrast to the ratio of redox couple (GSH/GSSG) related to antioxidative system during hyper-osmotic stress. Further, the ratio of GSH/GSSG decreased in the presence of sub-optimal temperature, while the ratio of Malate/OAA showed no visible changes. Also, the redox ratios of pyridine nucleotides increased under hyper-osmotic (NADH/NAD) and sub-optimal temperature (NADPH/NADP) stresses, respectively. However, upon restriction of AOX pathway by using salicylhydroxamic acid (SHAM), the observed changes in NaHCO3-dependent O2 evolution, cellular ROS, redox ratios of Malate/OAA, NAD(P)H/NAD(P) and GSH/GSSG were further aggravated under stress conditions with concomitant modulations in NADP-MDH and antioxidant enzymes. Taken together, the results indicated the importance of AOX pathway in optimizing photosynthesis under both hyper-osmotic stress and sub-optimal temperatures. Regulation of ROS through redox couples related to malate valve and antioxidant system by AOX pathway to optimize photosynthesis under these stresses are discussed.
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Affiliation(s)
- Challabathula Dinakar
- Department of Plant Sciences, School of Life Sciences, University of HyderabadHyderabad, India
- Department of Life Sciences, School of Basic and Applied Sciences, Central University of Tamil NaduThiruvarur, India
| | - Abhaypratap Vishwakarma
- Department of Plant Sciences, School of Life Sciences, University of HyderabadHyderabad, India
| | - Agepati S. Raghavendra
- Department of Plant Sciences, School of Life Sciences, University of HyderabadHyderabad, India
| | - Kollipara Padmasree
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of HyderabadHyderabad, India
- *Correspondence: Kollipara Padmasree, ;
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Vishwakarma A, Tetali SD, Selinski J, Scheibe R, Padmasree K. Importance of the alternative oxidase (AOX) pathway in regulating cellular redox and ROS homeostasis to optimize photosynthesis during restriction of the cytochrome oxidase pathway in Arabidopsis thaliana. ANNALS OF BOTANY 2015; 116:555-69. [PMID: 26292995 PMCID: PMC4578005 DOI: 10.1093/aob/mcv122] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 03/13/2015] [Accepted: 06/08/2015] [Indexed: 05/17/2023]
Abstract
BACKGROUND AND AIMS The importance of the alternative oxidase (AOX) pathway, particularly AOX1A, in optimizing photosynthesis during de-etiolation, under elevated CO2, low temperature, high light or combined light and drought stress is well documented. In the present study, the role of AOX1A in optimizing photosynthesis was investigated when electron transport through the cytochrome c oxidase (COX) pathway was restricted at complex III. METHODS Leaf discs of wild-type (WT) and aox1a knock-out mutants of Arabidopsis thaliana were treated with antimycin A (AA) under growth-light conditions. To identify the impact of AOX1A deficiency in optimizing photosynthesis, respiratory O2 uptake and photosynthesis-related parameters were measured along with changes in redox couples, reactive oxygen species (ROS), lipid peroxidation and expression levels of genes related to respiration, the malate valve and the antioxidative system. KEY RESULTS In the absence of AA, aox1a knock-out mutants did not show any difference in physiological, biochemical or molecular parameters compared with WT. However, after AA treatment, aox1a plants showed a significant reduction in both respiratory O2 uptake and NaHCO3-dependent O2 evolution. Chlorophyll fluorescence and P700 studies revealed that in contrast to WT, aox1a knock-out plants were incapable of maintaining electron flow in the chloroplastic electron transport chain, and thereby inefficient heat dissipation (low non-photochemical quenching) was observed. Furthermore, aox1a mutants exhibited significant disturbances in cellular redox couples of NAD(P)H and ascorbate (Asc) and consequently accumulation of ROS and malondialdehyde (MDA) content. By contrast, WT plants showed a significant increase in transcript levels of CSD1, CAT1, sAPX, COX15 and AOX1A in contrast to aox1a mutants. CONCLUSIONS These results suggest that AOX1A plays a significant role in sustaining the chloroplastic redox state and energization to optimize photosynthesis by regulating cellular redox homeostasis and ROS generation when electron transport through the COX pathway is disturbed at complex III.
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Affiliation(s)
- Abhaypratap Vishwakarma
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, India
| | - Sarada Devi Tetali
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, India
| | - Jennifer Selinski
- Department of Plant Physiology, FB5, University of Osnabrück, 49069 Osnabrück, Germany and
| | - Renate Scheibe
- Department of Plant Physiology, FB5, University of Osnabrück, 49069 Osnabrück, Germany and
| | - Kollipara Padmasree
- Department of Biotechnology and Bioinformatics, University of Hyderabad, Hyderabad 500 046, India
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General patterns of acclimation of leaf respiration to elevated temperatures across biomes and plant types. Oecologia 2014; 177:885-900. [DOI: 10.1007/s00442-014-3159-4] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 11/10/2014] [Indexed: 10/24/2022]
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