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Steen CJ, Niklas J, Poluektov OG, Schaller RD, Fleming GR, Utschig LM. EPR Spin-Trapping for Monitoring Temporal Dynamics of Singlet Oxygen during Photoprotection in Photosynthesis. Biochemistry 2024; 63:1214-1224. [PMID: 38679935 PMCID: PMC11080054 DOI: 10.1021/acs.biochem.4c00028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 04/14/2024] [Accepted: 04/17/2024] [Indexed: 05/01/2024]
Abstract
A central goal of photoprotective energy dissipation processes is the regulation of singlet oxygen (1O2*) and reactive oxygen species in the photosynthetic apparatus. Despite the involvement of 1O2* in photodamage and cell signaling, few studies directly correlate 1O2* formation to nonphotochemical quenching (NPQ) or lack thereof. Here, we combine spin-trapping electron paramagnetic resonance (EPR) and time-resolved fluorescence spectroscopies to track in real time the involvement of 1O2* during photoprotection in plant thylakoid membranes. The EPR spin-trapping method for detection of 1O2* was first optimized for photosensitization in dye-based chemical systems and then used to establish methods for monitoring the temporal dynamics of 1O2* in chlorophyll-containing photosynthetic membranes. We find that the apparent 1O2* concentration in membranes changes throughout a 1 h period of continuous illumination. During an initial response to high light intensity, the concentration of 1O2* decreased in parallel with a decrease in the chlorophyll fluorescence lifetime via NPQ. Treatment of membranes with nigericin, an uncoupler of the transmembrane proton gradient, delayed the activation of NPQ and the associated quenching of 1O2* during high light. Upon saturation of NPQ, the concentration of 1O2* increased in both untreated and nigericin-treated membranes, reflecting the utility of excess energy dissipation in mitigating photooxidative stress in the short term (i.e., the initial ∼10 min of high light).
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Affiliation(s)
- Collin J. Steen
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Molecular
Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jens Niklas
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
| | - Oleg G. Poluektov
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
| | - Richard D. Schaller
- Center
for Nanoscale Materials, Argonne National
Laboratory, Lemont, Illinois 60439, United States
| | - Graham R. Fleming
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Molecular
Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Lisa M. Utschig
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
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Demircan N, Sonmez MC, Akyol TY, Ozgur R, Turkan I, Dietz KJ, Uzilday B. Alternative electron sinks in chloroplasts and mitochondria of halophytes as a safety valve for controlling ROS production during salinity. PHYSIOLOGIA PLANTARUM 2024; 176:e14397. [PMID: 38894507 DOI: 10.1111/ppl.14397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/07/2024] [Accepted: 05/12/2024] [Indexed: 06/21/2024]
Abstract
Electron flow through the electron transport chain (ETC) is essential for oxidative phosphorylation in mitochondria and photosynthesis in chloroplasts. Electron fluxes depend on environmental parameters, e.g., ionic and osmotic conditions and endogenous factors, and this may cause severe imbalances. Plants have evolved alternative sinks to balance the reductive load on the electron transport chains in order to avoid overreduction, generation of reactive oxygen species (ROS), and to cope with environmental stresses. These sinks act primarily as valves for electron drainage and secondarily as regulators of tolerance-related metabolism, utilizing the excess reductive energy. High salinity is an environmental stressor that stimulates the generation of ROS and oxidative stress, which affects growth and development by disrupting the redox homeostasis of plants. While glycophytic plants are sensitive to high salinity, halophytic plants tolerate, grow, and reproduce at high salinity. Various studies have examined the ETC systems of glycophytic plants, however, information about the state and regulation of ETCs in halophytes under non-saline and saline conditions is scarce. This review focuses on alternative electron sinks in chloroplasts and mitochondria of halophytic plants. In cases where information on halophytes is lacking, we examined the available knowledge on the relationship between alternative sinks and gradual salinity resilience of glycophytes. To this end, transcriptional responses of involved components of photosynthetic and respiratory ETCs were compared between the glycophyte Arabidopsis thaliana and the halophyte Schrenkiella parvula, and the time-courses of these transcripts were examined in A. thaliana. The observed regulatory patterns are discussed in the context of reactive molecular species formation in halophytes and glycophytes.
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Affiliation(s)
- Nil Demircan
- Department of Biology, Faculty of Science, Ege University, Izmir, Türkiye
| | | | - Turgut Yigit Akyol
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Rengin Ozgur
- Department of Biology, Faculty of Science, Ege University, Izmir, Türkiye
| | - Ismail Turkan
- Department of Soil and Plant Nutrition, Faculty of Agricultural Sciences and Technologies, Yasar University, İzmir, Türkiye
| | - Karl-Josef Dietz
- Faculty of Biology, Department of Biochemistry and Physiology of Plants, University of Bielefeld, Bielefeld, Germany
| | - Baris Uzilday
- Department of Biology, Faculty of Science, Ege University, Izmir, Türkiye
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Yang Y, Zhang X, Zhong Q, Liu X, Guan H, Chen R, Hao Y, Yang X. Photosynthesis Response and Transcriptional Analysis: Dissecting the Role of SlHB8 in Regulating Drought Resistance in Tomato Plants. Int J Mol Sci 2023; 24:15498. [PMID: 37895176 PMCID: PMC10607914 DOI: 10.3390/ijms242015498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/20/2023] [Accepted: 10/20/2023] [Indexed: 10/29/2023] Open
Abstract
Deciphering drought resistance in crops is crucial for enhancing water productivity. Previous studies have highlighted the significant role of the transcription factor SlHB8 in regulating developmental processes in tomato plants but its involvement in drought resistance remains unclear. Here, gene overexpression (SlHB8-OE) and gene knockout (slhb8) tomato plants were utilized to study the role of SlHB8 in regulating drought resistance. Our findings showed that slhb8 plants exhibited a robust resistant phenotype under drought stress conditions. The stomata of slhb8 tomato leaves displayed significant closure, effectively mitigating the adverse effects of drought stress on photosynthetic efficiency. The slhb8 plants exhibited a decrease in oxidative damage and a substantial increase in antioxidant enzyme activity. Moreover, slhb8 effectively alleviated the degree of photoinhibition and chloroplast damage caused by drought stress. SlHB8 regulates the expression of numerous genes related to photosynthesis (such as SlPSAN, SlPSAL, SlPSBP, and SlTIC62) and stress signal transduction (such as SlCIPK25, SlABA4, and SlJA2) in response to drought stress. Additionally, slhb8 plants exhibited enhanced water absorption capacity and upregulated expression of several aquaporin genes including SlPIP1;3, SlPIP2;6, SlTIP3;1, SlNIP1;2, and SlXIP1;1. Collectively, our findings suggest that SlHB8 plays a negative regulatory role in the drought resistance of tomato plants.
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Affiliation(s)
| | | | | | | | | | | | - Yanwei Hao
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China; (Y.Y.); (X.Z.); (Q.Z.); (X.L.); (H.G.); (R.C.)
| | - Xiaolong Yang
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China; (Y.Y.); (X.Z.); (Q.Z.); (X.L.); (H.G.); (R.C.)
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Jia L, Liu L, Zhang Y, Fu W, Liu X, Wang Q, Tanveer M, Huang L. Microplastic stress in plants: effects on plant growth and their remediations. FRONTIERS IN PLANT SCIENCE 2023; 14:1226484. [PMID: 37636098 PMCID: PMC10452891 DOI: 10.3389/fpls.2023.1226484] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Accepted: 07/10/2023] [Indexed: 08/29/2023]
Abstract
Microplastic (MP) pollution is becoming a global problem due to the resilience, long-term persistence, and robustness of MPs in different ecosystems. In terrestrial ecosystems, plants are exposed to MP stress, thereby affecting overall plant growth and development. This review article has critically analyzed the effects of MP stress in plants. We found that MP stress-induced reduction in plant physical growth is accompanied by two complementary effects: (i) blockage of pores in seed coat or roots to alter water and nutrient uptake, and (ii) induction of drought due to increased soil cracking effects of MPs. Nonetheless, the reduction in physiological growth under MP stress is accompanied by four complementary effects: (i) excessive production of ROS, (ii) alteration in leaf and root ionome, (iii) impaired hormonal regulation, and (iv) decline in chlorophyll and photosynthesis. Considering that, we suggested that targeting the redox regulatory mechanisms could be beneficial in improving tolerance to MPs in plants; however, antioxidant activities are highly dependent on plant species, plant tissue, MP type, and MP dose. MP stress also indirectly reduces plant growth by altering soil productivity. However, MP-induced negative effects vary due to the presence of different surface functional groups and particle sizes. In the end, we suggested the utilization of agronomic approaches, including the application of growth regulators, biochar, and replacing plastic mulch with crop residues, crop diversification, and biological degradation, to ameliorate the effects of MP stress in plants. The efficiency of these methods is also MP-type-specific and dose-dependent.
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Affiliation(s)
- Li Jia
- College of Food and Drug, Luoyang Normal University, Luoyang, Henan, China
| | - Lining Liu
- International Research Center for Environmental Membrane Biology, College of Food Science and Engineering, Foshan University, Foshan, China
| | - Yujing Zhang
- International Research Center for Environmental Membrane Biology, College of Food Science and Engineering, Foshan University, Foshan, China
| | - Wenxuan Fu
- International Research Center for Environmental Membrane Biology, College of Food Science and Engineering, Foshan University, Foshan, China
| | - Xing Liu
- International Research Center for Environmental Membrane Biology, College of Food Science and Engineering, Foshan University, Foshan, China
| | - Qianqian Wang
- International Research Center for Environmental Membrane Biology, College of Food Science and Engineering, Foshan University, Foshan, China
| | - Mohsin Tanveer
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, TAS, Australia
| | - Liping Huang
- International Research Center for Environmental Membrane Biology, College of Food Science and Engineering, Foshan University, Foshan, China
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Shimakawa G. Electron transport in cyanobacterial thylakoid membranes: Are cyanobacteria simple models for photosynthetic organisms? JOURNAL OF EXPERIMENTAL BOTANY 2023:erad118. [PMID: 37025010 DOI: 10.1093/jxb/erad118] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Indexed: 06/19/2023]
Abstract
Cyanobacteria are structurally the simplest oxygenic phototrophs, which makes it difficult to understand the regulation of photosynthesis because the photosynthetic and respiratory processes share the same thylakoid membranes and cytosolic space. This review aimed to summarise the molecular mechanisms and in vivo activities of electron transport in cyanobacterial thylakoid membranes based on the latest progress in photosynthesis research in cyanobacteria. Photosynthetic linear electron transport for CO2 assimilation has the dominant electron flux in the thylakoid membranes. The capacity of O2 photoreduction in cyanobacteria is comparable to the photosynthetic CO2 assimilation, which is mediated by flavodiiron proteins. Additionally, cyanobacterial thylakoid membranes harbour the significant electron flux of respiratory electron transport through a homologue of respiratory complex I, which is also recognized as the part of cyclic electron transport chain if it is coupled with photosystem I in the light. Further, O2-independent alternative electron transports through hydrogenase and nitrate reductase function with reduced ferredoxin as the electron donor. Whereas all these electron transports are recently being understood one by one, the complexity as the whole regulatory system remains to be uncovered in near future.
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Affiliation(s)
- Ginga Shimakawa
- Department of Bioscience, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan
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The Functions of Chloroplastic Ascorbate in Vascular Plants and Algae. Int J Mol Sci 2023; 24:ijms24032537. [PMID: 36768860 PMCID: PMC9916717 DOI: 10.3390/ijms24032537] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/17/2023] [Accepted: 01/24/2023] [Indexed: 01/31/2023] Open
Abstract
Ascorbate (Asc) is a multifunctional metabolite essential for various cellular processes in plants and animals. The best-known property of Asc is to scavenge reactive oxygen species (ROS), in a highly regulated manner. Besides being an effective antioxidant, Asc also acts as a chaperone for 2-oxoglutarate-dependent dioxygenases that are involved in the hormone metabolism of plants and the synthesis of various secondary metabolites. Asc also essential for the epigenetic regulation of gene expression, signaling and iron transport. Thus, Asc affects plant growth, development, and stress resistance via various mechanisms. In this review, the intricate relationship between Asc and photosynthesis in plants and algae is summarized in the following major points: (i) regulation of Asc biosynthesis by light, (ii) interaction between photosynthetic and mitochondrial electron transport in relation to Asc biosynthesis, (iii) Asc acting as an alternative electron donor of photosystem II, (iv) Asc inactivating the oxygen-evolving complex, (v) the role of Asc in non-photochemical quenching, and (vi) the role of Asc in ROS management in the chloroplast. The review also discusses differences in the regulation of Asc biosynthesis and the effects of Asc on photosynthesis in algae and vascular plants.
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Wu P, Ma Y, Ahammed GJ, Hao B, Chen J, Wan W, Zhao Y, Cui H, Xu W, Cui J, Liu H. Insights into melatonin-induced photosynthetic electron transport under low-temperature stress in cucumber. FRONTIERS IN PLANT SCIENCE 2022; 13:1029854. [PMID: 36407604 PMCID: PMC9671077 DOI: 10.3389/fpls.2022.1029854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
In this study, the differences in chlorophyll fluorescence transient (OJIP) and modulated 820 nm reflection (MR820) of cucumber leaves were probed to demonstrate an insight into the precise influence of melatonin (MT) on cucumber photosystems under low temperature stress. We pre-treated cucumber seedlings with different levels of MT (0, 25, 50, 100, 200, and 400 μmol · L-1) before imposing low temperature stress (10 °C/6 °C). The results indicated that moderate concentrations of MT had a positive effect on the growth of low temperature-stressed cucumber seedlings. Under low temperature stress conditions, 100 μmol · L-1 (MT 100) improved the performance of the active photosystem II (PSII) reaction centers (PIabs), the oxygen evolving complex activity (OEC centers) and electron transport between PSII and PSI, mainly by decreasing the L-band, K-band, and G-band, but showed differences with different duration of low temperature stress. In addition, these indicators related to quantum yield and energy flux of PSII regulated by MT indicated that MT (MT 100) effectively protected the electron transport and energy distribution in the photosystem. According to the results of WO-I ≥ 1 and MR820 signals, MT also affected PSI activity. MT 100 decreased the minimal value of MR/MRO and the oxidation rate of plastocyanin (PC) and PSI reaction center (P700) (Vox ), while increased △MRslow/MRO and deoxidation rates of PC+ and P700 + (Vred ). The loss of the slow phase of MT 200 and MT 400-treated plants in the MR820 kinetics was due to the complete prevention of electron movement from PSII to re-reduce the PC+ and P700 +. These results suggest that appropriate MT concentration (100 μmol · L-1) can improve the photosynthetic performance of PS II and electron transport from primary quinone electron acceptor (QA) to secondary quinone electron acceptor (QB), promote the balance of energy distribution, strengthen the connectivity of PSI and PSII, improve the electron flow of PSII via QA to PC+ and P700 + from reaching PSI by regulating multiple sites of electron transport chain in photosynthesis, and increase the pool size and reduction rates of PSI in low temperature-stressed cucumber plants, All these modifications by MT 100 treatment promoted the photosynthetic electron transfer smoothly, and further restored the cucumber plant growth under low temperature stress. Therefore, we conclude that spraying MT at an appropriate concentration is beneficial for protecting the photosynthetic electron transport chain, while spraying high concentrations of MT has a negative effect on regulating the low temperature tolerance in cucumber.
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Affiliation(s)
- Pei Wu
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi, China
- The Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization in Xinjiang Production and Construction Group, Shihezi University, Shihezi, China
| | - Yadong Ma
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi, China
- The Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization in Xinjiang Production and Construction Group, Shihezi University, Shihezi, China
| | - Golam Jalal Ahammed
- College of Horticulture and Plant Protection, Henan University of Science and Technology, Luoyang, China
| | - Baoyu Hao
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi, China
- The Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization in Xinjiang Production and Construction Group, Shihezi University, Shihezi, China
| | - Jingyi Chen
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi, China
- The Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization in Xinjiang Production and Construction Group, Shihezi University, Shihezi, China
| | - Wenliang Wan
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi, China
- The Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization in Xinjiang Production and Construction Group, Shihezi University, Shihezi, China
| | - Yanhui Zhao
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi, China
- The Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization in Xinjiang Production and Construction Group, Shihezi University, Shihezi, China
| | - Huimei Cui
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi, China
- The Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization in Xinjiang Production and Construction Group, Shihezi University, Shihezi, China
| | - Wei Xu
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi, China
- The Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization in Xinjiang Production and Construction Group, Shihezi University, Shihezi, China
| | - Jinxia Cui
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi, China
- The Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization in Xinjiang Production and Construction Group, Shihezi University, Shihezi, China
| | - Huiying Liu
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi, China
- The Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization in Xinjiang Production and Construction Group, Shihezi University, Shihezi, China
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