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Artins A, Martins MCM, Meyer C, Fernie AR, Caldana C. Sensing and regulation of C and N metabolism - novel features and mechanisms of the TOR and SnRK1 signaling pathways. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:1268-1280. [PMID: 38349940 DOI: 10.1111/tpj.16684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/25/2024] [Accepted: 02/02/2024] [Indexed: 02/15/2024]
Abstract
Carbon (C) and nitrogen (N) metabolisms are tightly integrated to allow proper plant growth and development. Photosynthesis is dependent on N invested in chlorophylls, enzymes, and structural components of the photosynthetic machinery, while N uptake and assimilation rely on ATP, reducing equivalents, and C-skeletons provided by photosynthesis. The direct connection between N availability and photosynthetic efficiency allows the synthesis of precursors for all metabolites and building blocks in plants. Thus, the capacity to sense and respond to sudden changes in C and N availability is crucial for plant survival and is mediated by complex yet efficient signaling pathways such as TARGET OF RAPAMYCIN (TOR) and SUCROSE-NON-FERMENTING-1-RELATED PROTEIN KINASE 1 (SnRK1). In this review, we present recent advances in mechanisms involved in sensing C and N status as well as identifying current gaps in our understanding. We finally attempt to provide new perspectives and hypotheses on the interconnection of diverse signaling pathways that will allow us to understand the integration and orchestration of the major players governing the regulation of the CN balance.
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Affiliation(s)
- Anthony Artins
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam, Golm, Germany
| | - Marina C M Martins
- in Press - Scientific Consulting and Communication Services, 05089-030, São Paulo, São Paulo, Brazil
| | - Christian Meyer
- Institut Jean-Pierre Bourgin (IJPB), INRAE, AgroParisTech, Université Paris-Saclay, 78000, Versailles, France
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam, Golm, Germany
| | - Camila Caldana
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam, Golm, Germany
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2
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Belyaeva NE, Bulychev AA, Klementiev KE, Paschenko VZ, Riznichenko GY, Rubin AB. Comparative modeling of fluorescence and P700 induction kinetics for alga Scenedesmus sp. obliques and cyanobacterium Synechocystis sp. PCC 6803. Role of state 2-state 1 transitions and redox state of plastoquinone pool. Cell Biochem Biophys 2024:10.1007/s12013-024-01224-w. [PMID: 38340281 DOI: 10.1007/s12013-024-01224-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Accepted: 01/24/2024] [Indexed: 02/12/2024]
Abstract
The model of thylakoid membrane system (T-M model) (Belyaeva et al. Photosynth Res 2019, 140:1-19) has been improved in order to analyze the induction data for dark-adapted samples of algal (Scenedesmus obliques) and cyanobacterial (Synechocystis sp. PCC 6803) cells. The fluorescence induction (FI) curves of Scenedesmus were measured at light exposures of 5 min, while FI and P700 redox transformations of Synechocystis were recorded in parallel for 100 s intervals. Kinetic data comprising the OJIP-SMT fluorescence induction and OABCDEF P700+ absorbance changes were used to study the processes underlying state transitions qT2→1 and qT1→2 associated with the increase/decrease in Chl fluorescence emission. A formula with the Hill kinetics (Ebenhöh et al. Philos Trans R Soc B 2014, 369:20130223) was introduced into the T-M model, with a new variable to imitate the flexible size of antenna AntM(t) associated with PSII. Simulations revealed that the light-harvesting capacity of PSII increases with a corresponding decrease for that of PSI upon the qT2→1 transition induced by plastoquinone (PQ) pool oxidation. The complete T-M model fittings were attained on Scenedesmus or Synechocystis fast waves OJIPS of FI, while SMT wave of FI was reproduced at intervals shorter than 5 min. Also the fast P700 redox transitions (OABC) for Synechocystis were fitted exactly. Reasonable sets of algal and cyanobacterial electron/proton transfer (ET/PT) parameters were found. In the case of Scenedesmus, ET/PT traits remained the same irrespective of modeling with or without qT2→1 transitions. Simulations indicated a high extent (20%) of the PQ pool reduction under dark conditions in Synechocystis compared to 2% in Scenedesmus.
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Affiliation(s)
- N E Belyaeva
- Biological Faculty, Moscow State University, Moscow, 119234, Russia.
| | - A A Bulychev
- Biological Faculty, Moscow State University, Moscow, 119234, Russia
| | - K E Klementiev
- Biological Faculty, Moscow State University, Moscow, 119234, Russia
- Biological Faculty, Shenzhen MSU-BIT University, Shenzhen, 518172, China
| | - V Z Paschenko
- Biological Faculty, Moscow State University, Moscow, 119234, Russia
| | - G Yu Riznichenko
- Biological Faculty, Moscow State University, Moscow, 119234, Russia
| | - A B Rubin
- Biological Faculty, Moscow State University, Moscow, 119234, Russia
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3
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Li D, Gu B, Huang C, Shen J, Wang X, Guo J, Yu R, Mou S, Guan Q. Functional Study of Amorpha fruticosa WRKY20 Gene in Response to Drought Stress. Int J Mol Sci 2023; 24:12231. [PMID: 37569607 PMCID: PMC10418629 DOI: 10.3390/ijms241512231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/13/2023] Open
Abstract
The WRKY gene family in plants regulates the plant's response to drought through regulatory networks and hormone signaling. AfWRKY20 (MT859405) was cloned from Amorpha fruticosa (A. fruticosa) seedlings using RT-PCR. The binding properties of the AfWRKY20 protein and the W-box (a DNA cis-acting element) were verified both in vivo and in vitro using EMSA and Dual-Luciferase activity assays. RT-qPCR detected that the total expression level of AfWRKY20 in leaves and roots was 22 times higher in the 30% PEG6000 simulated drought treatment compared to the untreated group. Under the simulated drought stress treatments of sorbitol and abscisic acid (ABA), the transgenic tobacco with the AfWRKY20 gene showed enhanced drought resistance at the germination stage, with significantly increased germination rate, green leaf rate, fresh weight, and root length compared to the wild-type (WT) tobacco. In addition, the superoxide dismutase (SOD) activity, chlorophyll content, and Fv/Fm ratio of AfWRKY20 transgenic tobacco were significantly higher than those of the WT tobacco under natural drought stress, while the malondialdehyde (MDA) content and 3,3'-diaminobenzidine (DAB) and nitroblue tetrazolium (NBT) staining levels were lower. The expression levels of oxidation kinase genes (NbSOD, NbPOD, and NbCAT) in transgenic tobacco under drought stress were significantly higher than those in WT tobacco. This enhancement in gene expression improved the ability of transgenic tobacco to detoxify reactive oxygen species (ROS). The survival rate of transgenic tobacco after natural drought rehydration was four times higher than that of WT tobacco. In summary, this study revealed the regulatory mechanism of AfWRKY20 in response to drought stress-induced ABA signaling, particularly in relation to ROS. This finding provides a theoretical basis for understanding the pathways of WRKY20 involved in drought stress, and offers genetic resources for molecular plant breeding aimed at enhancing drought resistance.
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Affiliation(s)
- Danni Li
- Key Laboratory of the Ministry of Education for Ecological Restoration of Saline Vegetation, College of Life Sciences, Northeast Forestry University, Harbin 150040, China; (D.L.)
| | - Baoxiang Gu
- Key Laboratory of the Ministry of Education for Ecological Restoration of Saline Vegetation, College of Life Sciences, Northeast Forestry University, Harbin 150040, China; (D.L.)
| | - Chunxi Huang
- Northeast Asia Biodiversity Research Center, Northeast Forestry University, Harbin 150040, China
| | - Jiayi Shen
- Northeast Asia Biodiversity Research Center, Northeast Forestry University, Harbin 150040, China
| | - Xin Wang
- Key Laboratory of the Ministry of Education for Ecological Restoration of Saline Vegetation, College of Life Sciences, Northeast Forestry University, Harbin 150040, China; (D.L.)
| | - Jianan Guo
- Key Laboratory of the Ministry of Education for Ecological Restoration of Saline Vegetation, College of Life Sciences, Northeast Forestry University, Harbin 150040, China; (D.L.)
| | - Ruiqiang Yu
- Northeast Asia Biodiversity Research Center, Northeast Forestry University, Harbin 150040, China
| | - Sirui Mou
- Key Laboratory of the Ministry of Education for Ecological Restoration of Saline Vegetation, College of Life Sciences, Northeast Forestry University, Harbin 150040, China; (D.L.)
| | - Qingjie Guan
- Key Laboratory of the Ministry of Education for Ecological Restoration of Saline Vegetation, College of Life Sciences, Northeast Forestry University, Harbin 150040, China; (D.L.)
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Saroussi S, Redekop P, Karns DAJ, Thomas DC, Wittkopp TM, Posewitz MC, Grossman AR. Restricting electron flow at cytochrome b6f when downstream electron acceptors are severely limited. PLANT PHYSIOLOGY 2023; 192:789-804. [PMID: 36960590 PMCID: PMC10231464 DOI: 10.1093/plphys/kiad185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 06/01/2023]
Abstract
Photosynthetic organisms frequently experience abiotic stress that restricts their growth and development. Under such circumstances, most absorbed solar energy cannot be used for CO2 fixation and can cause the photoproduction of reactive oxygen species (ROS) that can damage the photosynthetic reaction centers of PSI and PSII, resulting in a decline in primary productivity. This work describes a biological "switch" in the green alga Chlamydomonas reinhardtii that reversibly restricts photosynthetic electron transport (PET) at the cytochrome b6f (Cyt b6f) complex when the capacity for accepting electrons downstream of PSI is severely limited. We specifically show this restriction in STARCHLESS6 (sta6) mutant cells, which cannot synthesize starch when they are limited for nitrogen (growth inhibition) and subjected to a dark-to-light transition. This restriction represents a form of photosynthetic control that causes diminished electron flow to PSI and thereby prevents PSI photodamage but does not appear to rely on a ΔpH. Furthermore, when electron flow is restricted, the plastid alternative oxidase (PTOX) becomes active, functioning as an electron valve that dissipates some excitation energy absorbed by PSII and allows the formation of a proton motive force (PMF) that would drive some ATP production (potentially sustaining PSII repair and nonphotochemical quenching [NPQ]). The restriction at the Cyt b6f complex can be gradually relieved with continued illumination. This study provides insights into how PET responds to a marked reduction in availability of downstream electron acceptors and the protective mechanisms involved.
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Affiliation(s)
- Shai Saroussi
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Petra Redekop
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Devin A J Karns
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Dylan C Thomas
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Tyler M Wittkopp
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Matthew C Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA
| | - Arthur R Grossman
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA 94305, USA
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Suwannachuen N, Leetanasaksakul K, Roytrakul S, Phaonakrop N, Thaisakun S, Roongsattham P, Jantasuriyarat C, Sanevas N, Sirikhachornkit A. Palmelloid Formation and Cell Aggregation Are Essential Mechanisms for High Light Tolerance in a Natural Strain of Chlamydomonas reinhardtii. Int J Mol Sci 2023; 24:ijms24098374. [PMID: 37176080 PMCID: PMC10179368 DOI: 10.3390/ijms24098374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/01/2023] [Accepted: 05/05/2023] [Indexed: 05/15/2023] Open
Abstract
Photosynthetic organisms, such as higher plants and algae, require light to survive. However, an excessive amount of light can be harmful due to the production of reactive oxygen species (ROS), which cause cell damage and, if it is not effectively regulated, cell death. The study of plants' responses to light can aid in the development of methods to improve plants' growth and productivity. Due to the multicellular nature of plants, there may be variations in the results based on plant age and tissue type. Chlamydomonas reinhardtii, a unicellular green alga, has also been used as a model organism to study photosynthesis and photoprotection. Nonetheless, the majority of the research has been conducted with strains that have been consistently utilized in laboratories and originated from the same source. Despite the availability of many field isolates of this species, very few studies have compared the light responses of field isolates. This study examined the responses of two field isolates of Chlamydomonas to high light stress. The light-tolerant strain, CC-4414, managed reactive oxygen species (ROS) slightly better than the sensitive strain, CC-2344, did. The proteomic data of cells subjected to high light revealed cellular modifications of the light-tolerant strain toward membrane proteins. The morphology of cells under light stress revealed that this strain utilized the formation of palmelloid structures and cell aggregation to shield cells from excessive light. As indicated by proteome data, morphological modifications occur simultaneously with the increase in protein degradation and autophagy. By protecting cells from stress, cells are able to continue to upregulate ROS management mechanisms and prevent cell death. This is the first report of palmelloid formation in Chlamydomonas under high light stress.
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Affiliation(s)
- Nittaya Suwannachuen
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand
- Center for Advanced Studies in Tropical Natural Resources, National Research University-Kasetsart University, Bangkok 10900, Thailand
| | - Kantinan Leetanasaksakul
- Functional Proteomics Technology Laboratory, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Paholyothin Road, Klong 1, Klong Luang, Pathum Thani 12120, Thailand
| | - Sittiruk Roytrakul
- Functional Proteomics Technology Laboratory, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Paholyothin Road, Klong 1, Klong Luang, Pathum Thani 12120, Thailand
| | - Narumon Phaonakrop
- Functional Proteomics Technology Laboratory, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Paholyothin Road, Klong 1, Klong Luang, Pathum Thani 12120, Thailand
| | - Siriwan Thaisakun
- Functional Proteomics Technology Laboratory, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Paholyothin Road, Klong 1, Klong Luang, Pathum Thani 12120, Thailand
| | - Peerapat Roongsattham
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand
- Center for Advanced Studies in Tropical Natural Resources, National Research University-Kasetsart University, Bangkok 10900, Thailand
| | - Chatchawan Jantasuriyarat
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand
- Center for Advanced Studies in Tropical Natural Resources, National Research University-Kasetsart University, Bangkok 10900, Thailand
| | - Nuttha Sanevas
- Department of Botany, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand
| | - Anchalee Sirikhachornkit
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand
- Center for Advanced Studies in Tropical Natural Resources, National Research University-Kasetsart University, Bangkok 10900, Thailand
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6
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Gu L, Grodzinski B, Han J, Marie T, Zhang YJ, Song YC, Sun Y. An exploratory steady-state redox model of photosynthetic linear electron transport for use in complete modelling of photosynthesis for broad applications. PLANT, CELL & ENVIRONMENT 2023; 46:1540-1561. [PMID: 36760139 DOI: 10.1111/pce.14563] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/24/2023] [Accepted: 02/05/2023] [Indexed: 06/18/2023]
Abstract
A photochemical model of photosynthetic electron transport (PET) is needed to integrate photophysics, photochemistry, and biochemistry to determine redox conditions of electron carriers and enzymes for plant stress assessment and mechanistically link sun-induced chlorophyll fluorescence to carbon assimilation for remotely sensing photosynthesis. Towards this goal, we derived photochemical equations governing the states and redox reactions of complexes and electron carriers along the PET chain. These equations allow the redox conditions of the mobile plastoquinone pool and the cytochrome b6 f complex (Cyt) to be inferred with typical fluorometry. The equations agreed well with fluorometry measurements from diverse C3 /C4 species across environments in the relationship between the PET rate and fraction of open photosystem II reaction centres. We found the oxidation of plastoquinol by Cyt is the bottleneck of PET, and genetically improving the oxidation of plastoquinol by Cyt may enhance the efficiency of PET and photosynthesis across species. Redox reactions and photochemical and biochemical interactions are highly redundant in their complex controls of PET. Although individual reaction rate constants cannot be resolved, they appear in parameter groups which can be collectively inferred with fluorometry measurements for broad applications. The new photochemical model developed enables advances in different fronts of photosynthesis research.
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Affiliation(s)
- Lianhong Gu
- Oak Ridge National Laboratory, Environmental Sciences Division and Climate Change Science Institute, Oak Ridge, Tennessee, USA
| | - Bernard Grodzinski
- Department of Plant Agriculture, University of Guelph, Guelph, Ontario, Canada
| | - Jimei Han
- School of Integrative Plant Science, Cornell University, Ithaca, New York, USA
| | - Telesphore Marie
- Department of Plant Agriculture, University of Guelph, Guelph, Ontario, Canada
| | - Yong-Jiang Zhang
- School of Biology and Ecology, University of Maine, Orono, Maine, USA
| | - Yang C Song
- Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, Arizona, USA
| | - Ying Sun
- School of Integrative Plant Science, Cornell University, Ithaca, New York, USA
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7
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Santana‐Sánchez A, Nikkanen L, Werner E, Tóth G, Ermakova M, Kosourov S, Walter J, He M, Aro E, Allahverdiyeva Y. Flv3A facilitates O 2 photoreduction and affects H 2 photoproduction independently of Flv1A in diazotrophic Anabaena filaments. THE NEW PHYTOLOGIST 2023; 237:126-139. [PMID: 36128660 PMCID: PMC10092803 DOI: 10.1111/nph.18506] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 09/10/2022] [Indexed: 05/23/2023]
Abstract
The model heterocyst-forming filamentous cyanobacterium Anabaena sp. PCC 7120 (Anabaena) is a typical example of a multicellular organism capable of simultaneously performing oxygenic photosynthesis in vegetative cells and O2 -sensitive N2 -fixation inside heterocysts. The flavodiiron proteins have been shown to participate in photoprotection of photosynthesis by driving excess electrons to O2 (a Mehler-like reaction). Here, we performed a phenotypic and biophysical characterization of Anabaena mutants impaired in vegetative-specific Flv1A and Flv3A in order to address their physiological relevance in the bioenergetic processes occurring in diazotrophic Anabaena under variable CO2 conditions. We demonstrate that both Flv1A and Flv3A are required for proper induction of the Mehler-like reaction upon a sudden increase in light intensity, which is likely important for the activation of carbon-concentrating mechanisms and CO2 fixation. Under ambient CO2 diazotrophic conditions, Flv3A is responsible for moderate O2 photoreduction, independently of Flv1A, but only in the presence of Flv2 and Flv4. Strikingly, the lack of Flv3A resulted in strong downregulation of the heterocyst-specific uptake hydrogenase, which led to enhanced H2 photoproduction under both oxic and micro-oxic conditions. These results reveal a novel regulatory network between the Mehler-like reaction and the diazotrophic metabolism, which is of great interest for future biotechnological applications.
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Affiliation(s)
- Anita Santana‐Sánchez
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Lauri Nikkanen
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Elisa Werner
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Gábor Tóth
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Maria Ermakova
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Sergey Kosourov
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Julia Walter
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Meilin He
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Eva‐Mari Aro
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Life TechnologiesUniversity of TurkuTurkuFI‐20014Finland
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8
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Gu L, Grodzinski B, Han J, Marie T, Zhang Y, Song YC, Sun Y. Granal thylakoid structure and function: explaining an enduring mystery of higher plants. THE NEW PHYTOLOGIST 2022; 236:319-329. [PMID: 35832001 PMCID: PMC9805053 DOI: 10.1111/nph.18371] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 07/07/2022] [Indexed: 05/11/2023]
Abstract
In higher plants, photosystems II and I are found in grana stacks and unstacked stroma lamellae, respectively. To connect them, electron carriers negotiate tortuous multi-media paths and are subject to macromolecular blocking. Why does evolution select an apparently unnecessary, inefficient bipartition? Here we systematically explain this perplexing phenomenon. We propose that grana stacks, acting like bellows in accordions, increase the degree of ultrastructural control on photosynthesis through thylakoid swelling/shrinking induced by osmotic water fluxes. This control coordinates with variations in stomatal conductance and the turgor of guard cells, which act like an accordion's air button. Thylakoid ultrastructural dynamics regulate macromolecular blocking/collision probability, direct diffusional pathlengths, division of function of Cytochrome b6 f complex between linear and cyclic electron transport, luminal pH via osmotic water fluxes, and the separation of pH dynamics between granal and lamellar lumens in response to environmental variations. With the two functionally asymmetrical photosystems located distantly from each other, the ultrastructural control, nonphotochemical quenching, and carbon-reaction feedbacks maximally cooperate to balance electron transport with gas exchange, provide homeostasis in fluctuating light environments, and protect photosystems in drought. Grana stacks represent a dry/high irradiance adaptation of photosynthetic machinery to improve fitness in challenging land environments. Our theory unifies many well-known but seemingly unconnected phenomena of thylakoid structure and function in higher plants.
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Affiliation(s)
- Lianhong Gu
- Environmental Sciences Division and Climate Change Science InstituteOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Bernard Grodzinski
- Department of Plant AgricultureUniversity of GuelphGuelphONN1G 2W1Canada
| | - Jimei Han
- School of Integrative Plant ScienceCornell UniversityIthacaNY14853USA
| | - Telesphore Marie
- Department of Plant AgricultureUniversity of GuelphGuelphONN1G 2W1Canada
| | | | - Yang C. Song
- Department of Hydrology and Atmospheric SciencesUniversity of ArizonaTucsonAZ85721USA
| | - Ying Sun
- School of Integrative Plant ScienceCornell UniversityIthacaNY14853USA
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9
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Han Y, Wang Q, Li Q, Hu C. Active metabolism and biomass dynamics of biocrusts are shaped by variation in their successional state and seasonal energy sources. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 831:154756. [PMID: 35339556 DOI: 10.1016/j.scitotenv.2022.154756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 06/14/2023]
Abstract
Seasonal growth and changes in biomass within communities are the core of ecosystem dynamics. Biocrusts play a prominent role as pioneers in dryland soils. However, the seasonal dynamics of biocrusts remain poorly resolved. In this study, we collected biocrusts across a successional gradient (cyanobacteria, cyanolichen, chlorolichen, and moss-dominated) from southeastern Tengger Desert (China) during the summer and autumn seasons, and explored seasonal changes in metabolism and biomass using multi-omics approaches. We found that Cyanobacteria and Ascomycota were the dominant active taxa and both exhibited higher abundances in autumn. We also found that the dominant primary producers in biocrusts strongly affected community-wide characteristics of metabolism. Along with seasonal differences in light energy utilization, utilization of inorganic energy sources exhibited higher expression in the summer while for organic sources, in the autumn. We found that overall metabolism was significantly regulated by the ratio of intracellular to extracellular polymer degradation, and affected by NO3-, PO43- and EC (in the summer)/NO2- (in the autumn). In summary, biocrust growth varied with seasonal variation in light energy utilization and complementary chemical energy sources, with the most suitable season varying with biocrust successional type.
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Affiliation(s)
- Yingchun Han
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiong Wang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qi Li
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chunxiang Hu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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10
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Choi BY, Kim H, Shim D, Jang S, Yamaoka Y, Shin S, Yamano T, Kajikawa M, Jin E, Fukuzawa H, Lee Y. The Chlamydomonas bZIP transcription factor BLZ8 confers oxidative stress tolerance by inducing the carbon-concentrating mechanism. THE PLANT CELL 2022; 34:910-926. [PMID: 34893905 PMCID: PMC8824676 DOI: 10.1093/plcell/koab293] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 11/28/2021] [Indexed: 05/19/2023]
Abstract
Photosynthetic organisms are exposed to various environmental sources of oxidative stress. Land plants have diverse mechanisms to withstand oxidative stress, but how microalgae do so remains unclear. Here, we characterized the Chlamydomonas reinhardtii basic leucine zipper (bZIP) transcription factor BLZ8, which is highly induced by oxidative stress. Oxidative stress tolerance increased with increasing BLZ8 expression levels. BLZ8 regulated the expression of genes likely involved in the carbon-concentrating mechanism (CCM): HIGH-LIGHT ACTIVATED 3 (HLA3), CARBONIC ANHYDRASE 7 (CAH7), and CARBONIC ANHYDRASE 8 (CAH8). BLZ8 expression increased the photosynthetic affinity for inorganic carbon under alkaline stress conditions, suggesting that BLZ8 induces the CCM. BLZ8 expression also increased the photosynthetic linear electron transfer rate, reducing the excitation pressure of the photosynthetic electron transport chain and in turn suppressing reactive oxygen species (ROS) production under oxidative stress conditions. A carbonic anhydrase inhibitor, ethoxzolamide, abolished the enhanced tolerance to alkaline stress conferred by BLZ8 overexpression. BLZ8 directly regulated the expression of the three target genes and required bZIP2 as a dimerization partner in activating CAH8 and HLA3. Our results suggest that a CCM-mediated increase in the CO2 supply for photosynthesis is critical to minimize oxidative damage in microalgae, since slow gas diffusion in aqueous environments limits CO2 availability for photosynthesis, which can trigger ROS formation.
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Affiliation(s)
| | | | - Donghwan Shim
- Department of Biological Sciences, Chungnam National University, Daejeon 34134 Korea
| | - Sunghoon Jang
- Department of Life Science, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea
| | | | - Seungjun Shin
- Department of Life Science, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea
| | - Takashi Yamano
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | | | - EonSeon Jin
- Department of Life Science, Hanyang University, Seoul 133-791, South Korea
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11
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Rog I, Chaturvedi AK, Tiwari V, Danon A. Low light-regulated intramolecular disulfide fine-tunes the role of PTOX in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 109:585-597. [PMID: 34767654 DOI: 10.1111/tpj.15579] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 11/01/2021] [Accepted: 11/08/2021] [Indexed: 06/13/2023]
Abstract
Disulfide-based regulation links the activity of numerous chloroplast proteins with photosynthesis-derived redox signals. The plastid terminal oxidase (PTOX) is a thylakoid-bound plastoquinol oxidase that has been implicated in multiple roles in the light and in the dark, which could require different levels of PTOX activity. Here we show that Arabidopsis PTOX contains a conserved C-terminus domain (CTD) with cysteines that evolved progressively following the colonization of the land by plants. Furthermore, the CTD contains a regulatory disulfide that is in the oxidized state in the dark and is rapidly reduced, within 5 min, in low light intensity (1-5 µE m-2 sec-1 ). The reduced PTOX form in the light was reoxidized within 15 min after transition to the dark. Mutation of the cysteines in the CTD prevented the formation of the oxidized form. This resulted in higher levels of reduced plastoquinone when measured at transition to the onset of low light. This is consistent with the reduced state of PTOX exhibiting diminished PTOX oxidase activity under conditions of limiting PQH2 substrate. Our findings suggest that AtPTOX-CTD evolved to provide light-dependent regulation of PTOX activity for the adaptation of plants to terrestrial conditions.
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Affiliation(s)
- Ido Rog
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Amit Kumar Chaturvedi
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Vivekanand Tiwari
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Avihai Danon
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
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12
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Abstract
The target of rapamycin (TOR) kinase is a master regulator that integrates nutrient signals to promote cell growth in all eukaryotes. It is well established that amino acids and glucose are major regulators of TOR signaling in yeast and metazoan, but whether and how TOR responds to carbon availability in photosynthetic organisms is less understood. In this study, we showed that photosynthetic assimilation of CO2 by the Calvin-Benson-Bassham (CBB) cycle regulates TOR activity in the model single-celled microalga Chlamydomonas reinhardtii Stimulation of CO2 fixation boosted TOR activity, whereas inhibition of the CBB cycle and photosynthesis down-regulated TOR. We uncovered a tight link between TOR activity and the endogenous level of a set of amino acids including Ala, Glu, Gln, Leu, and Val through the modulation of CO2 fixation and the use of amino acid synthesis inhibitors. Moreover, the finding that the Chlamydomonas starch-deficient mutant sta6 displayed disproportionate TOR activity and high levels of most amino acids, particularly Gln, further connected carbon assimilation and amino acids to TOR signaling. Thus, our results showed that CO2 fixation regulates TOR signaling, likely through the synthesis of key amino acids.
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13
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Avgoustaki DD, Bartzanas T, Xydis G. Minimising the energy footprint of indoor food production while maintaining a high growth rate: Introducing disruptive cultivation protocols. Food Control 2021. [DOI: 10.1016/j.foodcont.2021.108290] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Wakao S, Niyogi KK. Chlamydomonas as a model for reactive oxygen species signaling and thiol redox regulation in the green lineage. PLANT PHYSIOLOGY 2021; 187:687-698. [PMID: 35237823 PMCID: PMC8491031 DOI: 10.1093/plphys/kiab355] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/13/2021] [Indexed: 05/15/2023]
Abstract
One-sentence summary: Advances in proteomic and transcriptomic studies have made Chlamydomonas a powerful research model in redox and reactive oxygen species regulation with unique and overlapping mechanisms with plants.
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Affiliation(s)
- Setsuko Wakao
- Division of Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
- Author for communication: Senior author
| | - Krishna K. Niyogi
- Division of Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
- Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA
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15
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Nikkanen L, Solymosi D, Jokel M, Allahverdiyeva Y. Regulatory electron transport pathways of photosynthesis in cyanobacteria and microalgae: Recent advances and biotechnological prospects. PHYSIOLOGIA PLANTARUM 2021; 173:514-525. [PMID: 33764547 DOI: 10.1111/ppl.13404] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
Cyanobacteria and microalgae perform oxygenic photosynthesis where light energy is harnessed to split water into oxygen and protons. This process releases electrons that are used by the photosynthetic electron transport chain to form reducing equivalents that provide energy for the cell metabolism. Constant changes in environmental conditions, such as light availability, temperature, and access to nutrients, create the need to balance the photochemical reactions and the metabolic demands of the cell. Thus, cyanobacteria and microalgae evolved several auxiliary electron transport (AET) pathways to disperse the potentially harmful over-supply of absorbed energy. AET pathways are comprised of electron sinks, e.g. flavodiiron proteins (FDPs) or other terminal oxidases, and pathways that recycle electrons around photosystem I, like NADPH-dehydrogenase-like complexes (NDH) or the ferredoxin-plastoquinone reductase (FQR). Under controlled conditions the need for these AET pathways is decreased and AET can even be energetically wasteful. Therefore, redirecting photosynthetic reducing equivalents to biotechnologically useful reactions, catalyzed by i.e. innate hydrogenases or heterologous enzymes, offers novel possibilities to apply photosynthesis research.
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Affiliation(s)
- Lauri Nikkanen
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, Finland
| | - Daniel Solymosi
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, Finland
| | - Martina Jokel
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, Finland
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, Finland
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16
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Liu Y, Zhang S, Yang F, Wang G, Jing X, Wang X, You C. New strategy of light quality regulation with leaf-spraying fluorescent coatings for enhancing photosynthesis efficiency. RSC Adv 2021; 11:26620-26628. [PMID: 35480016 PMCID: PMC9037335 DOI: 10.1039/d1ra03695e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 07/26/2021] [Indexed: 11/30/2022] Open
Abstract
Fluorescent coatings are a kind of emerging light quality regulation material that can improve plant light utilization efficiency through easy manipulation at a low price. Compared with the scheme of fluorescent nanomaterials alone or those physically dispersed in polymeric materials for photosynthesis enhancement, fluorescent polymeric coatings (FPCs) originating from the covalent copolymerization of nanomaterial monomers can function stably and continuously, circumventing the high-cost manipulation of continuous leaf-spraying or hydroponics of the previous scheme in practical applications. Herein, we developed a kind of FPCs consisting of UV-to-blue light-converting nitrogen-doped carbon dots (N-CDs) as the fluorescent monomer to induce the copolymerization of N-CDs and tannic acid (TA). In the FPCs, N-CDs and TA are covalently cross-linked together. The fluorescent ability of N-CDs and the strong adhesion of TA are integrated organically to the whole to endow FPCs with excellent properties of prolonged fluorescence capacity, rain-erosion resistance and stability. After spraying FPCs on tomato leaves grown under the full spectrum, both the chlorophyll content of the leaves and effective photochemical efficiency were increased significantly, and the growth rate was promoted with 38.3% and 43.2% enhancement in the dry and fresh weight. We also analyzed the human cytotoxicity of the coating and the toxicological experiments showed that the coating did not affect the proliferation of human cells. An UV-excited solid-state fluorescent and erosion-resistant coating based on the copolymerization of tannic acid and carbon dots is developed for increasing photosynthesis and accelerating plant growth.![]()
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Affiliation(s)
- Yankai Liu
- National Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production, College of Horticulture Science and Engineering, Shandong Agricultural University Tai-An Shandong 271018 China
| | - Shuai Zhang
- College of Chemistry and Material Science, Shandong Agricultural University Tai-An Shandong 271018 China
| | - Fei Yang
- National Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production, College of Horticulture Science and Engineering, Shandong Agricultural University Tai-An Shandong 271018 China
| | - Guanzhu Wang
- National Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production, College of Horticulture Science and Engineering, Shandong Agricultural University Tai-An Shandong 271018 China
| | - Xiuli Jing
- National Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production, College of Horticulture Science and Engineering, Shandong Agricultural University Tai-An Shandong 271018 China
| | - Xiaofei Wang
- National Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production, College of Horticulture Science and Engineering, Shandong Agricultural University Tai-An Shandong 271018 China
| | - Chunxiang You
- National Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production, College of Horticulture Science and Engineering, Shandong Agricultural University Tai-An Shandong 271018 China
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17
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Huang W, Sun H, Tan SL, Zhang SB. The water-water cycle is not a major alternative sink in fluctuating light at chilling temperature. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 305:110828. [PMID: 33691962 DOI: 10.1016/j.plantsci.2021.110828] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 11/30/2020] [Accepted: 01/12/2021] [Indexed: 05/13/2023]
Abstract
The water-water cycle (WWC) has the potential to alleviate photoinhibition of photosystem I (PSI) in fluctuating light (FL) at room temperature and moderate heat stress. However, it is unclear whether WWC can function as a safety valve for PSI in FL at chilling temperature. In this study, we measured P700 redox state and chlorophyll fluorescence in FL at 25 °C and 4 °C in the high WWC activity plant Dendrobium officinale. At 25 °C, the operation of WWC contributed to the rapid re-oxidation of P700 upon dark-to-light transition. However, such rapid re-oxidation of P700 was not observed at 4 °C. Upon a sudden increase in light intensity, WWC rapidly consumed excess electrons in PSI and thus avoided an over-reduction of PSI at 25 °C. On the contrary, PSI was highly reduced within the first seconds after transition from low to high light at 4 °C. Therefore, in opposite to 25 °C, the WWC is not a major alternative sink in FL at chilling temperature. Upon transition from low to high light, cyclic electron transport was highly stimulated at 4 °C when compared with 25 °C. These results indicate that D. officinale enhances cyclic electron transport to partially compensate for the inactivation of WWC in FL at 4 °C.
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Affiliation(s)
- Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; Bio-Innovation Center of DR PLANT, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
| | - Hu Sun
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shun-Ling Tan
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
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18
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Kedem I, Milrad Y, Kaplan A, Yacoby I. Juggling Lightning: How Chlorella ohadii handles extreme energy inputs without damage. PHOTOSYNTHESIS RESEARCH 2021; 147:329-344. [PMID: 33389446 DOI: 10.1007/s11120-020-00809-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 12/03/2020] [Indexed: 06/12/2023]
Abstract
The green alga Chlorella ohadii was isolated from a desert biological soil crust, one of the harshest environments on Earth. When grown under optimal laboratory settings it shows the fastest growth rate ever reported for a photosynthetic eukaryote and a complete resistance to photodamage even under unnaturally high light intensities. Here we examined the energy distribution along the photosynthetic pathway under four light and carbon regimes. This was performed using various methodologies such as membrane inlet mass spectrometer with stable O2 isotopes, variable fluorescence, electrochromic shift and fluorescence assessment of NADPH level, as well as the use of specific inhibitors. We show that the preceding illumination and CO2 level during growth strongly affect the energy dissipation strategies employed by the cell. For example, plastid terminal oxidase (PTOX) plays an important role in energy dissipation, particularly in high light- and low-CO2-grown cells. Of particular note is the reliance on PSII cyclic electron flow as an effective and flexible dissipation mechanism in all conditions tested. The energy management observed here may be unique to C. ohadii, as it is the only known organism to cope with such conditions. However, the strategies demonstrated may provide an insight into the processes necessary for photosynthesis under high-light conditions.
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Affiliation(s)
- Isaac Kedem
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel
| | - Yuval Milrad
- School of Plant Sciences and Food Security, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel.
| | - Iftach Yacoby
- School of Plant Sciences and Food Security, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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19
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Assil-Companioni L, Büchsenschütz HC, Solymosi D, Dyczmons-Nowaczyk NG, Bauer KKF, Wallner S, Macheroux P, Allahverdiyeva Y, Nowaczyk MM, Kourist R. Engineering of NADPH Supply Boosts Photosynthesis-Driven Biotransformations. ACS Catal 2020; 10:11864-11877. [PMID: 33101760 PMCID: PMC7574619 DOI: 10.1021/acscatal.0c02601] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 09/04/2020] [Indexed: 02/08/2023]
Abstract
![]()
Light-driven biocatalysis
in recombinant cyanobacteria provides
highly atom-efficient cofactor regeneration via photosynthesis,
thereby remediating constraints associated with sacrificial cosubstrates.
However, despite the remarkable specific activities of photobiocatalysts,
self-shading at moderate-high cell densities limits efficient space-time-yields
of heterologous enzymatic reactions. Moreover, efficient integration
of an artificial electron sink into the tightly regulated network
of cyanobacterial electron pathways can be highly challenging. Here,
we used C=C bond reduction of 2-methylmaleimide by the NADPH-dependent
ene-reductase YqjM as a model reaction for light-dependent biotransformations.
Time-resolved NADPH fluorescence spectroscopy allowed direct monitoring
of in-cell YqjM activity and revealed differences in NADPH steady-state
levels and oxidation kinetics between different genetic constructs.
This effect correlates with specific activities of whole-cells, which
demonstrated conversions of >99%. Further channelling of electrons
toward heterologous YqjM by inactivation of the flavodiiron proteins
(Flv1/Flv3) led to a 2-fold improvement in specific activity at moderate
cell densities, thereby elucidating the possibility of accelerating
light-driven biotransformations by the removal of natural competing
electron sinks. In the best case, an initial product formation rate
of 18.3 mmol h–1 L–1 was reached,
allowing the complete conversion of a 60 mM substrate solution within
4 h.
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Affiliation(s)
- Leen Assil-Companioni
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
- ACIB GmbH, Petersgasse 14, 8010 Graz, Austria
| | - Hanna C. Büchsenschütz
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
| | - Dániel Solymosi
- Molecular Plant Biology unit, Department of Biochemistry, Faculty of Science and Engineering, University of Turku, Turku 20014, Finland
| | - Nina G. Dyczmons-Nowaczyk
- Department of Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Kristin K. F. Bauer
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
| | - Silvia Wallner
- Institute of Biochemistry, Graz University of Technology, Petersgasse 10, 8010 Graz, Austria
| | - Peter Macheroux
- Institute of Biochemistry, Graz University of Technology, Petersgasse 10, 8010 Graz, Austria
| | - Yagut Allahverdiyeva
- Molecular Plant Biology unit, Department of Biochemistry, Faculty of Science and Engineering, University of Turku, Turku 20014, Finland
| | - Marc M. Nowaczyk
- Department of Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Robert Kourist
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
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20
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Deficiency in flavodiiron protein Flv3 promotes cyclic electron flow and state transition under high light in the cyanobacterium Synechocystis sp. PCC 6803. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148318. [PMID: 32979345 DOI: 10.1016/j.bbabio.2020.148318] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 09/11/2020] [Accepted: 09/19/2020] [Indexed: 11/21/2022]
Abstract
Photosynthetic organisms adjust their activity to changes in irradiance by different ways, including the operation of cyclic electron flow around photosystem I (PSI) and state transitions that redistribute amounts of light energy absorbed by PSI and PSII. In dark-acclimated wild type cells of Synechocystis PCC 6803, linear electron transport was activated after the first 500 ms of illumination, while cyclic electron flow around PSI was long predominant in the mutant deficient in flavodiiron protein Flv3. Chlorophyll P700 oxidation associated with activation of linear electron flow extended in the Flv3- mutant to several tens of seconds and included a P700+ re-reduction phase. Parallel monitoring of chlorophyll fluorescence and the redox state of P700 indicated that, at low light intensity both in wild type and in the Flv3- mutant, the transient re-reduction step coincided in time with S-M fluorescence rise, which reflected state 2-state 1 transition (Kaňa et al., 2012). Despite variations in the initial redox state of plastoquinone pool, the oxidases-deficient mutant, succinate dehydrogenase-deficient mutant, and wild type cells did not show the S-M rise under high-intensity light until additional Flv3- mutation was introduced in these strains. Thus, the lack of available electron acceptor for PSI was the main cause for the appearance of S-M fluorescence rise under high light. It is concluded that the lack of Flv3 protein promotes cyclic electron flow around PSI and facilitates the subsequent state 2-state 1 transition in the absence of strict relation to the dark-operated pathways of plastoquinone reduction or oxidation.
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21
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Ueno Y, Shimakawa G, Aikawa S, Miyake C, Akimoto S. Photoprotection mechanisms under different CO 2 regimes during photosynthesis in a green alga Chlorella variabilis. PHOTOSYNTHESIS RESEARCH 2020; 144:397-407. [PMID: 32377933 DOI: 10.1007/s11120-020-00757-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 04/23/2020] [Indexed: 05/28/2023]
Abstract
Oxygenic photosynthesis converts light energy into chemical energy via electron transport and assimilates CO2 in the Calvin-Benson cycle with the chemical energy. Thus, high light and low CO2 conditions induce the accumulation of electrons in the photosynthetic electron transport system, resulting in the formation of reactive oxygen species. To prevent the accumulation of electrons, oxygenic photosynthetic organisms have developed photoprotection mechanisms, including non-photochemical quenching (NPQ) and alternative electron flow (AEF). There are diverse molecular mechanisms underlying NPQ and AEF, and the corresponding molecular actors have been identified and characterized using a model green alga Chlamydomonas reinhardtii. In contrast, detailed information about the photoprotection mechanisms is lacking for other green algal species. In the current study, we examined the photoprotection mechanisms responsive to CO2 in the green alga Chlorella variabilis by combining the analyses of pulse-amplitude-modulated fluorescence, O2 evolution, and the steady-state and time-resolved fluorescence spectra. Under the CO2-limited condition, ΔpH-dependent NPQ occurred in photosystems I and II. Moreover, O2-dependent AEF was also induced. Under the CO2-limited condition with carbon supplementation, NPQ was relaxed and light-harvesting chlorophyll-protein complex II was isolated from both photosystems. In C. variabilis, the O2-dependent AEF and the mechanisms that instantly convert the light-harvesting functions of both photosystems may be important for maintaining efficient photosynthetic activities under various CO2 conditions.
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Affiliation(s)
- Yoshifumi Ueno
- Graduate School of Science, Kobe University, Kobe, 657-8501, Japan.
| | - Ginga Shimakawa
- Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
- Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Shimpei Aikawa
- Japan International Research Center for Agricultural Sciences, Tsukuba, 305-8686, Japan
| | - Chikahiro Miyake
- Graduate School of Agricultural Science, Kobe University, Kobe, 657-8501, Japan
| | - Seiji Akimoto
- Graduate School of Science, Kobe University, Kobe, 657-8501, Japan.
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22
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Bunbury F, Helliwell KE, Mehrshahi P, Davey MP, Salmon DL, Holzer A, Smirnoff N, Smith AG. Responses of a Newly Evolved Auxotroph of Chlamydomonas to B 12 Deprivation. PLANT PHYSIOLOGY 2020; 183:167-178. [PMID: 32079734 PMCID: PMC7210614 DOI: 10.1104/pp.19.01375] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 02/04/2020] [Indexed: 05/10/2023]
Abstract
The corrinoid B12 is synthesized only by prokaryotes yet is widely required by eukaryotes as an enzyme cofactor. Microalgae have evolved B12 dependence on multiple occasions, and we previously demonstrated that experimental evolution of the non-B12-requiring alga Chlamydomonas reinhardtii in media supplemented with B12 generated a B12-dependent mutant (hereafter metE7). This clone provides a unique opportunity to study the physiology of a nascent B12 auxotroph. Our analyses demonstrate that B12 deprivation of metE7 disrupts C1 metabolism, causes an accumulation of starch and triacylglycerides, and leads to a decrease in photosynthetic pigments, proteins, and free amino acids. B12 deprivation also caused a substantial increase in reactive oxygen species, which preceded rapid cell death. Survival could be improved without compromising growth by simultaneously depriving the cells of nitrogen, suggesting a type of cross protection. Significantly, we found further improvements in survival under B12 limitation and an increase in B12 use efficiency after metE7 underwent a further period of experimental evolution, this time in coculture with a B12-producing bacterium. Therefore, although an early B12-dependent alga would likely be poorly adapted to coping with B12 deprivation, association with B12-producers can ensure long-term survival whilst also providing a suitable environment for evolving mechanisms to tolerate B12 limitation better.
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Affiliation(s)
- Freddy Bunbury
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, United Kingdom
| | - Katherine E Helliwell
- Marine Biological Association of the United Kingdom, Citadel Hill, Plymouth EX4 4PY, United Kingdom
- School of Biosciences, University of Exeter, Exeter, PL1 2PB, United Kingdom
| | - Payam Mehrshahi
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, United Kingdom
| | - Matthew P Davey
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, United Kingdom
| | - Deborah L Salmon
- School of Biosciences, University of Exeter, Exeter, PL1 2PB, United Kingdom
| | - Andre Holzer
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, United Kingdom
| | - Nicholas Smirnoff
- School of Biosciences, University of Exeter, Exeter, PL1 2PB, United Kingdom
| | - Alison G Smith
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, United Kingdom
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23
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Lacour T, Babin M, Lavaud J. Diversity in Xanthophyll Cycle Pigments Content and Related Nonphotochemical Quenching (NPQ) Among Microalgae: Implications for Growth Strategy and Ecology. JOURNAL OF PHYCOLOGY 2020; 56:245-263. [PMID: 31674660 DOI: 10.1111/jpy.12944] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 10/04/2019] [Indexed: 05/12/2023]
Abstract
Xanthophyll cycle-related nonphotochemical quenching (NPQ), which is present in most photoautotrophs, allows dissipation of excess light energy. Xanthophyll cycle-related NPQ depends principally on xanthophyll cycle pigments composition and their effective involvement in NPQ. Xanthophyll cycle-related NPQ is tightly controlled by environmental conditions in a species-/strain-specific manner. These features are especially relevant in microalgae living in a complex and highly variable environment. The goal of this study was to perform a comparative assessment of NPQ ecophysiologies across microalgal taxa in order to underline the specific involvement of NPQ in growth adaptations and strategies. We used both published results and data acquired in our laboratory to understand the relationships between growth conditions (irradiance, temperature, and nutrient availability), xanthophyll cycle composition, and xanthophyll cycle pigments quenching efficiency in microalgae from various taxa. We found that in diadinoxanthin-containing species, the xanthophyll cycle pigment pool is controlled by energy pressure in all species. At any given energy pressure, however, the diatoxanthin content is higher in diatoms than in other diadinoxanthin-containing species. XC pigments quenching efficiency is species-specific and decreases with acclimation to higher irradiances. We found a clear link between the natural light environment of species/ecotypes and quenching efficiency amplitude. The presence of diatoxanthin or zeaxanthin at steady state in all species examined at moderate and high irradiances suggests that cells maintain a light-harvesting capacity in excess to cope with potential decrease in light intensity.
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Affiliation(s)
| | - Marcel Babin
- Takuvik Joint International Laboratory UMI3376, CNRS (France) & ULaval (Canada), Département de Biologie, Université Laval, Pavillon Alexandre-Vachon, 1045, Avenue de la Médecine, Québec, QC, G1V 0A6, Canada
| | - Johann Lavaud
- Takuvik Joint International Laboratory UMI3376, CNRS (France) & ULaval (Canada), Département de Biologie, Université Laval, Pavillon Alexandre-Vachon, 1045, Avenue de la Médecine, Québec, QC, G1V 0A6, Canada
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Burlacot A, Peltier G, Li-Beisson Y. Subcellular Energetics and Carbon Storage in Chlamydomonas. Cells 2019; 8:E1154. [PMID: 31561610 PMCID: PMC6830334 DOI: 10.3390/cells8101154] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 09/19/2019] [Accepted: 09/24/2019] [Indexed: 01/09/2023] Open
Abstract
Microalgae have emerged as a promising platform for production of carbon- and energy- rich molecules, notably starch and oil. Establishing an economically viable algal biotechnology sector requires a holistic understanding of algal photosynthesis, physiology, cell cycle and metabolism. Starch/oil productivity is a combined effect of their cellular content and cell division activities. Cell growth, starch and fatty acid synthesis all require carbon building blocks and a source of energy in the form of ATP and NADPH, but with a different requirement in ATP/NADPH ratio. Thus, several cellular mechanisms have been developed by microalgae to balance ATP and NADPH supply which are essentially produced by photosynthesis. Major energy management mechanisms include ATP production by the chloroplast-based cyclic electron flow and NADPH removal by water-water cycles. Furthermore, energetic coupling between chloroplast and other cellular compartments, mitochondria and peroxisome, is increasingly recognized as an important process involved in the chloroplast redox poise. Emerging literature suggests that alterations of energy management pathways affect not only cell fitness and survival, but also influence biomass content and composition. These emerging discoveries are important steps towards diverting algal photosynthetic energy to useful products for biotechnological applications.
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Affiliation(s)
- Adrien Burlacot
- Aix Marseille Univ, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache CEDEX, 13108 Saint Paul-Lez-Durance, France.
| | - Gilles Peltier
- Aix Marseille Univ, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache CEDEX, 13108 Saint Paul-Lez-Durance, France.
| | - Yonghua Li-Beisson
- Aix Marseille Univ, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache CEDEX, 13108 Saint Paul-Lez-Durance, France.
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Jokel M, Nagy V, Tóth SZ, Kosourov S, Allahverdiyeva Y. Elimination of the flavodiiron electron sink facilitates long-term H 2 photoproduction in green algae. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:280. [PMID: 31827608 PMCID: PMC6894204 DOI: 10.1186/s13068-019-1618-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 11/23/2019] [Indexed: 05/14/2023]
Abstract
BACKGROUND The development of renewable and sustainable biofuels to cover the future energy demand is one of the most challenging issues of our time. Biohydrogen, produced by photosynthetic microorganisms, has the potential to become a green biofuel and energy carrier for the future sustainable world, since it provides energy without CO2 emission. The recent development of two alternative protocols to induce hydrogen photoproduction in green algae enables the function of the O2-sensitive [FeFe]-hydrogenases, located at the acceptor side of photosystem I, to produce H2 for several days. These protocols prevent carbon fixation and redirect electrons toward H2 production. In the present work, we employed these protocols to a knockout Chlamydomonas reinhardtii mutant lacking flavodiiron proteins (FDPs), thus removing another possible electron competitor with H2 production. RESULTS The deletion of the FDP electron sink resulted in the enhancement of H2 photoproduction relative to wild-type C. reinhardtii. Additionally, the lack of FDPs leads to a more effective obstruction of carbon fixation even under elongated light pulses. CONCLUSIONS We demonstrated that the rather simple adjustment of cultivation conditions together with genetic manipulation of alternative electron pathways of photosynthesis results in efficient re-routing of electrons toward H2 photoproduction. Furthermore, the introduction of a short recovery phase by regular switching from H2 photoproduction to biomass accumulation phase allows to maintain cell fitness and use photosynthetic cells as long-term H2-producing biocatalysts.
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Affiliation(s)
- Martina Jokel
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland
| | - Valéria Nagy
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland
| | - Szilvia Z. Tóth
- Institute of Plant Biology, Biological Research Centre, Szeged, Temesvári krt. 62, Szeged, 6726 Hungary
| | - Sergey Kosourov
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014 Turku, Finland
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