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Milrad Y, Mosebach L, Buchert F. Regulation of Microalgal Photosynthetic Electron Transfer. PLANTS (BASEL, SWITZERLAND) 2024; 13:2103. [PMID: 39124221 PMCID: PMC11314055 DOI: 10.3390/plants13152103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 07/24/2024] [Accepted: 07/26/2024] [Indexed: 08/12/2024]
Abstract
The global ecosystem relies on the metabolism of photosynthetic organisms, featuring the ability to harness light as an energy source. The most successful type of photosynthesis utilizes a virtually inexhaustible electron pool from water, but the driver of this oxidation, sunlight, varies on time and intensity scales of several orders of magnitude. Such rapid and steep changes in energy availability are potentially devastating for biological systems. To enable a safe and efficient light-harnessing process, photosynthetic organisms tune their light capturing, the redox connections between core complexes and auxiliary electron mediators, ion passages across the membrane, and functional coupling of energy transducing organelles. Here, microalgal species are the most diverse group, featuring both unique environmental adjustment strategies and ubiquitous protective mechanisms. In this review, we explore a selection of regulatory processes of the microalgal photosynthetic apparatus supporting smooth electron flow in variable environments.
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Affiliation(s)
- Yuval Milrad
- Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, 48143 Münster, Germany
| | - Laura Mosebach
- Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, 48143 Münster, Germany
| | - Felix Buchert
- Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, 48143 Münster, Germany
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Dou B, Li Y, Wang F, Chen L, Zhang W. Chassis engineering for high light tolerance in microalgae and cyanobacteria. Crit Rev Biotechnol 2024:1-19. [PMID: 38987975 DOI: 10.1080/07388551.2024.2357368] [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: 03/25/2024] [Accepted: 05/05/2024] [Indexed: 07/12/2024]
Abstract
Oxygenic photosynthesis in microalgae and cyanobacteria is considered an important chassis to accelerate energy transition and mitigate global warming. Currently, cultivation systems for photosynthetic microbes for large-scale applications encountered excessive light exposure stress. High light stress can: affect photosynthetic efficiency, reduce productivity, limit cell growth, and even cause cell death. Deciphering photoprotection mechanisms and constructing high-light tolerant chassis have been recent research focuses. In this review, we first briefly introduce the self-protection mechanisms of common microalgae and cyanobacteria in response to high light stress. These mechanisms mainly include: avoiding excess light absorption, dissipating excess excitation energy, quenching excessive high-energy electrons, ROS detoxification, and PSII repair. We focus on the species-specific differences in these mechanisms as well as recent advancements. Then, we review engineering strategies for creating high-light tolerant chassis, such as: reducing the size of the light-harvesting antenna, optimizing non-photochemical quenching, optimizing photosynthetic electron transport, and enhancing PSII repair. Finally, we propose a comprehensive exploration of mechanisms: underlying identified high light tolerant chassis, identification of new genes pertinent to high light tolerance using innovative methodologies, harnessing CRISPR systems and artificial intelligence for chassis engineering modification, and introducing plant photoprotection mechanisms as future research directions.
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Affiliation(s)
- Biyun Dou
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, P.R. China
| | - Yang Li
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, P.R. China
| | - Fangzhong Wang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, P.R. China
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin, P.R. China
| | - Lei Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, P.R. China
| | - Weiwen Zhang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, P.R. China
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin, P.R. China
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Kim M, Cazzaniga S, Jang J, Pivato M, Kim G, Ballottari M, Jin E. Photoautotrophic cultivation of a Chlamydomonas reinhardtii mutant with zeaxanthin as the sole xanthophyll. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:41. [PMID: 38486329 PMCID: PMC10941483 DOI: 10.1186/s13068-024-02483-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 02/24/2024] [Indexed: 03/17/2024]
Abstract
BACKGROUND Photosynthetic microalgae are known for their sustainable and eco-friendly potential to convert carbon dioxide into valuable products. Nevertheless, the challenge of self-shading due to high cell density has been identified as a drawback, hampering productivity in sustainable photoautotrophic mass cultivation. To address this issue, mutants with altered pigment composition have been proposed to allow a more efficient light diffusion but further study on the role of the different pigments is still needed to correctly engineer this process. RESULTS We here investigated the Chlamydomonas reinhardtii Δzl mutant with zeaxanthin as the sole xanthophyll. The Δzl mutant displayed altered pigment composition, characterized by lower chlorophyll content, higher chlorophyll a/b ratio, and lower chlorophyll/carotenoid ratio compared to the wild type (Wt). The Δzl mutant also exhibited a significant decrease in the light-harvesting complex II/Photosystem II ratio (LHCII/PSII) and the absence of trimeric LHCIIs. This significantly affects the organization and stability of PSII supercomplexes. Consequently, the estimated functional antenna size of PSII in the Δzl mutant was approximately 60% smaller compared to that of Wt, and reduced PSII activity was evident in this mutant. Notably, the Δzl mutant showed impaired non-photochemical quenching. However, the Δzl mutant compensated by exhibiting enhanced cyclic electron flow compared to Wt, seemingly offsetting the impaired PSII functionality. Consequently, the Δzl mutant achieved significantly higher cell densities than Wt under high-light conditions. CONCLUSIONS Our findings highlight significant changes in pigment content and pigment-protein complexes in the Δzl mutant compared to Wt, resulting in an advantage for high-density photoautotrophic cultivation. This advantage is attributed to the decreased chlorophyll content of the Δzl mutant, allowing better light penetration. In addition, the accumulated zeaxanthin in the mutant could serve as an antioxidant, offering protection against reactive oxygen species generated by chlorophylls.
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Affiliation(s)
- Minjae Kim
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, 04763, Korea
| | | | - Junhwan Jang
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, 04763, Korea
| | - Matteo Pivato
- Dipartimento di Biotecnologie, Università di Verona, Verona, Italy
| | - Gueeda Kim
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, 04763, Korea
| | | | - EonSeon Jin
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, 04763, Korea.
- Hanyang Institute of Bioscience and Biotechnology, Hanyang University, Seoul, 04763, Korea.
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Mehra HS, Wang X, Russell BP, Kulkarni N, Ferrari N, Larson B, Vinyard DJ. Assembly and Repair of Photosystem II in Chlamydomonas reinhardtii. PLANTS (BASEL, SWITZERLAND) 2024; 13:811. [PMID: 38592843 PMCID: PMC10975043 DOI: 10.3390/plants13060811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 03/05/2024] [Accepted: 03/07/2024] [Indexed: 04/11/2024]
Abstract
Oxygenic photosynthetic organisms use Photosystem II (PSII) to oxidize water and reduce plastoquinone. Here, we review the mechanisms by which PSII is assembled and turned over in the model green alga Chlamydomonas reinhardtii. This species has been used to make key discoveries in PSII research due to its metabolic flexibility and amenability to genetic approaches. PSII subunits originate from both nuclear and chloroplastic gene products in Chlamydomonas. Nuclear-encoded PSII subunits are transported into the chloroplast and chloroplast-encoded PSII subunits are translated by a coordinated mechanism. Active PSII dimers are built from discrete reaction center complexes in a process facilitated by assembly factors. The phosphorylation of core subunits affects supercomplex formation and localization within the thylakoid network. Proteolysis primarily targets the D1 subunit, which when replaced, allows PSII to be reactivated and completes a repair cycle. While PSII has been extensively studied using Chlamydomonas as a model species, important questions remain about its assembly and repair which are presented here.
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Affiliation(s)
| | | | | | | | | | | | - David J. Vinyard
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA; (H.S.M.); (X.W.); (B.P.R.); (N.K.); (N.F.); (B.L.)
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Morelli L, Havurinne V, Madeira D, Martins P, Cartaxana P, Cruz S. Photoprotective mechanisms in Elysia species hosting Acetabularia chloroplasts shed light on host-donor compatibility in photosynthetic sea slugs. PHYSIOLOGIA PLANTARUM 2024; 176:e14273. [PMID: 38566156 DOI: 10.1111/ppl.14273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/13/2024] [Accepted: 03/18/2024] [Indexed: 04/04/2024]
Abstract
Sacoglossa sea slugs have garnered attention due to their ability to retain intracellular functional chloroplasts from algae, while degrading other algal cell components. While protective mechanisms that limit oxidative damage under excessive light are well documented in plants and algae, the photoprotective strategies employed by these photosynthetic sea slugs remain unresolved. Species within the genus Elysia are known to retain chloroplasts from various algal sources, but the extent to which the metabolic processes from the donor algae can be sustained by the sea slugs is unclear. By comparing responses to high-light conditions through kinetic analyses, molecular techniques, and biochemical assays, this study shows significant differences between two photosynthetic Elysia species with chloroplasts derived from the green alga Acetabularia acetabulum. Notably, Elysia timida displayed remarkable tolerance to high-light stress and sophisticated photoprotective mechanisms such as an active xanthophyll cycle, efficient D1 protein recycling, accumulation of heat-shock proteins and α-tocopherol. In contrast, Elysia crispata exhibited absence or limitations in these photoprotective strategies. Our findings emphasize the intricate relationship between the host animal and the stolen chloroplasts, highlighting different capacities to protect the photosynthetic organelle from oxidative damage.
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Affiliation(s)
- Luca Morelli
- ECOMARE-Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Vesa Havurinne
- ECOMARE-Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Diana Madeira
- ECOMARE-Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Patrícia Martins
- ECOMARE-Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Paulo Cartaxana
- ECOMARE-Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Sónia Cruz
- ECOMARE-Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
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Li X, Jiang Z, Zhang C, Cai K, Wang H, Pan W, Sun X, Gao Y, Xu K. Comparative genomics analysis provide insights into evolution and stress responses of Lhcb genes in Rosaceae fruit crops. BMC PLANT BIOLOGY 2023; 23:484. [PMID: 37817059 PMCID: PMC10566169 DOI: 10.1186/s12870-023-04438-x] [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: 06/26/2023] [Accepted: 09/04/2023] [Indexed: 10/12/2023]
Abstract
BACKGROUND Light-harvesting chlorophyll a/b b evelopment of higher plants and in response to abiotic stress. Previous works has demonstrated that that Lhcb genes were involved in the phytochrome regulation and responded to the different light and temperature conditions in Poaceae (such as maize). However, the evolution and functions of Lhcb genes remains poorly characterized in important Rosaceae species. RESULTS In this investigation, we conducted a genome-wide analysis and identified a total of 212 Lhcb genes across nine Rosaceae species. Specifically, we found 23 Lhcb genes in Fragaria vesca, 20 in Prunus armeniaca, 33 in Malus domestica 'Gala', 21 in Prunus persica, 33 in Rosa chinensis, 29 in Pyrus bretschneideri, 18 in Rubus occidentalis, 20 in Prunus mume, and 15 in Prunus salicina. Phylogenetic analysis revealed that the Lhcb gene family could be classified into seven major subfamilies, with members of each subfamily sharing similar conserved motifs. And, the functions of each subfamily was predicted based on the previous reports from other species. The Lhcb proteins were highly conserved within their respective subfamilies, suggesting similar functions. Interestingly, we observed similar peaks in Ks values (0.1-0.2) for Lhcb genes in apple and pear, indicating a recent whole genome duplication event (about 30 to 45 million years ago). Additionally, a few Lhcb genes underwent tandem duplication and were located across all chromosomes of nine species of Rosaceae. Furthermore, the analysis of the cis-acting elements in the 2000 bp promoter region upstream of the pear Lhcb gene revealed four main categories: light response correlation, stress response correlation, hormone response correlation, and plant growth. Quantitative expression analysis demonstrated that Lhcb genes exhibited tissue-specific expression patterns and responded differently to low-temperature stress in Rosaceae species. CONCLUSIONS These findings shed light on the evolution and phylogeny of Lhcb genes in Rosaceae and highlight the critical role of Lhcb in pear's response to low temperatures. The results obtained provide valuable insights for further investigations into the functions of Lhcb genes in Rosaceae, and these functional genes will be used for further fruit tree breeding and improvement to cope with the current climate changes.
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Affiliation(s)
- Xiaolong Li
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, College of Horticulture Science, Zhejiang A&F University, Hangzhou, 311300, Zhejiang, China
| | - Zeyu Jiang
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, College of Horticulture Science, Zhejiang A&F University, Hangzhou, 311300, Zhejiang, China
| | - Chaofan Zhang
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Kefan Cai
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, College of Horticulture Science, Zhejiang A&F University, Hangzhou, 311300, Zhejiang, China
| | - Hui Wang
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, College of Horticulture Science, Zhejiang A&F University, Hangzhou, 311300, Zhejiang, China
| | - Weiyi Pan
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, College of Horticulture Science, Zhejiang A&F University, Hangzhou, 311300, Zhejiang, China
| | - Xuepeng Sun
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, College of Horticulture Science, Zhejiang A&F University, Hangzhou, 311300, Zhejiang, China
| | - Yongbin Gao
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, College of Horticulture Science, Zhejiang A&F University, Hangzhou, 311300, Zhejiang, China.
| | - Kai Xu
- Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, College of Horticulture Science, Zhejiang A&F University, Hangzhou, 311300, Zhejiang, China.
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Cazzaniga S, Kim M, Pivato M, Perozeni F, Sardar S, D'Andrea C, Jin E, Ballottari M. Photosystem II monomeric antenna CP26 plays a key role in nonphotochemical quenching in Chlamydomonas. PLANT PHYSIOLOGY 2023; 193:1365-1380. [PMID: 37403662 DOI: 10.1093/plphys/kiad391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/17/2023] [Accepted: 06/06/2023] [Indexed: 07/06/2023]
Abstract
Thermal dissipation of excess excitation energy, called nonphotochemical quenching (NPQ), is 1 of the main photoprotective mechanisms in oxygenic photosynthetic organisms. Here, we investigated the function of the monomeric photosystem II (PSII) antenna protein CP26 in photoprotection and light harvesting in Chlamydomonas reinhardtii, a model organism for green algae. We used CRISPR/Cas9 genome editing and complementation to generate cp26 knockout mutants (named k6#) that did not negatively affect CP29 accumulation, which differed from previous cp26 mutants, allowing us to compare mutants specifically deprived of CP26, CP29, or both. The absence of CP26 partially affected PSII activity, causing reduced growth at low or medium light but not at high irradiances. However, the main phenotype observed in k6# mutants was a more than 70% reduction of NPQ compared to the wild type (Wt). This phenotype was fully rescued by genetic complementation and complemented strains accumulating different levels of CP26, demonstrating that ∼50% of CP26 content, compared to the Wt, was sufficient to restore the NPQ capacity. Our findings demonstrate a pivotal role for CP26 in NPQ induction, while CP29 is crucial for PSII activity. The genetic engineering of these 2 proteins could be a promising strategy to regulate the photosynthetic efficiency of microalgae under different light regimes.
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Affiliation(s)
- Stefano Cazzaniga
- Dipartimento di Biotecnologie, Università di Verona, Verona 37134, Italy
| | - Minjae Kim
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, South Korea
| | - Matteo Pivato
- Dipartimento di Biotecnologie, Università di Verona, Verona 37134, Italy
| | - Federico Perozeni
- Dipartimento di Biotecnologie, Università di Verona, Verona 37134, Italy
| | - Samim Sardar
- Istituto Italiano di Tecnologia, Center for Nano Science and Technology, Milano 20134, Italy
| | - Cosimo D'Andrea
- Istituto Italiano di Tecnologia, Center for Nano Science and Technology, Milano 20134, Italy
- Dipartimento di Fisica, Politecnico di Milano, Milano 20133, Italy
| | - EonSeon Jin
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, South Korea
| | - Matteo Ballottari
- Dipartimento di Biotecnologie, Università di Verona, Verona 37134, Italy
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Cui J, Qiu T, Li L, Cui S. De novo full-length transcriptome analysis of two ecotypes of Phragmites australis (swamp reed and dune reed) provides new insights into the transcriptomic complexity of dune reed and its long-term adaptation to desert environments. BMC Genomics 2023; 24:180. [PMID: 37020272 PMCID: PMC10077656 DOI: 10.1186/s12864-023-09271-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 03/23/2023] [Indexed: 04/07/2023] Open
Abstract
BACKGROUND The extremely harsh environment of the desert is changing dramatically every moment, and the rapid adaptive stress response in the short term requires enormous energy expenditure to mobilize widespread regulatory networks, which is all the more detrimental to the survival of the desert plants themselves. The dune reed, which has adapted to desert environments with complex and variable ecological factors, is an ideal type of plant for studying the molecular mechanisms by which Gramineae plants respond to combinatorial stress of the desert in their natural state. But so far, the data on the genetic resources of reeds is still scarce, therefore most of their research has focused on ecological and physiological studies. RESULTS In this study, we obtained the first De novo non-redundant Full-Length Non-Chimeric (FLNC) transcriptome databases for swamp reeds (SR), dune reeds (DR) and the All of Phragmites australis (merged of iso-seq data from SR and DR), using PacBio Iso-Seq technology and combining tools such as Iso-Seq3 and Cogent. We then identified and described long non-coding RNAs (LncRNA), transcription factor (TF) and alternative splicing (AS) events in reeds based on a transcriptome database. Meanwhile, we have identified and developed for the first time a large number of candidates expressed sequence tag-SSR (EST-SSRs) markers in reeds based on UniTransModels. In addition, through differential gene expression analysis of wild-type and homogenous cultures, we found a large number of transcription factors that may be associated with desert stress tolerance in the dune reed, and revealed that members of the Lhc family have an important role in the long-term adaptation of dune reeds to desert environments. CONCLUSIONS Our results provide a positive and usable genetic resource for Phragmites australis with a widespread adaptability and resistance, and provide a genetic database for subsequent reeds genome annotation and functional genomic studies.
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Affiliation(s)
- Jipeng Cui
- College of Life Sciences, Capital Normal University, Haidian District, Beijing, 100048, China
- Beijing Key Laboratory of Plant Gene Resources and Biotechnology for Carbon Reduction and Environmental Improvement, Haidian District, Beijing, 100048, China
| | - Tianhang Qiu
- College of Life Sciences, Capital Normal University, Haidian District, Beijing, 100048, China
- Beijing Key Laboratory of Plant Gene Resources and Biotechnology for Carbon Reduction and Environmental Improvement, Haidian District, Beijing, 100048, China
| | - Li Li
- College of Life Sciences, Capital Normal University, Haidian District, Beijing, 100048, China
- Beijing Key Laboratory of Plant Gene Resources and Biotechnology for Carbon Reduction and Environmental Improvement, Haidian District, Beijing, 100048, China
| | - Suxia Cui
- College of Life Sciences, Capital Normal University, Haidian District, Beijing, 100048, China.
- Beijing Key Laboratory of Plant Gene Resources and Biotechnology for Carbon Reduction and Environmental Improvement, Haidian District, Beijing, 100048, China.
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Jeong BR, Jang J, Jin E. Genome engineering via gene editing technologies in microalgae. BIORESOURCE TECHNOLOGY 2023; 373:128701. [PMID: 36746216 DOI: 10.1016/j.biortech.2023.128701] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 01/27/2023] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Abstract
CRISPR-Cas has revolutionized genetic modification with its comparative simplicity and accuracy, and it can be used even at the genomic level. Microalgae are excellent feedstocks for biofuels and nutraceuticals because they contain high levels of fatty acids, carotenoids, and other metabolites; however, genome engineering for microalgae is not yet as developed as for other model organisms. Microalgal engineering at the genetic and metabolic levels is relatively well established, and a few genomic resources are available. Their genomic information was used for a "safe harbor" site for stable transgene expression in microalgae. This review proposes further genome engineering schemes including the construction of sgRNA libraries, pan-genomic and epigenomic resources, and mini-genomes, which can together be developed into synthetic biology for carbon-based engineering in microalgae. Acetyl-CoA is at the center of carbon metabolic pathways and is further reviewed for the production of molecules including terpenoids in microalgae.
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Affiliation(s)
- Byeong-Ryool Jeong
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - Junhwan Jang
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - EonSeon Jin
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea; Hanyang Institute of Bioscience and Biotechnology, Hanyang University, Seoul 04763, Korea.
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Cazzaniga S, Perozeni F, Baier T, Ballottari M. Engineering astaxanthin accumulation reduces photoinhibition and increases biomass productivity under high light in Chlamydomonas reinhardtii. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:77. [PMID: 35820961 PMCID: PMC9277849 DOI: 10.1186/s13068-022-02173-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 06/28/2022] [Indexed: 11/10/2022]
Abstract
Background Astaxanthin is a highly valuable ketocarotenoid with strong antioxidative activity and is natively accumulated upon environmental stress exposure in selected microorganisms. Green microalgae are photosynthetic, unicellular organisms cultivated in artificial systems to produce biomass and industrially relevant bioproducts. While light is required for photosynthesis, fueling carbon fixation processes, application of high irradiance causes photoinhibition and limits biomass productivity. Results Here, we demonstrate that engineered astaxanthin accumulation in the green alga Chlamydomonas reinhardtii conferred high light tolerance, reduced photoinhibition and improved biomass productivity at high irradiances, likely due to strong antioxidant properties of constitutively accumulating astaxanthin. In competitive co-cultivation experiments, astaxanthin-rich Chlamydomonas reinhardtii outcompeted its corresponding parental background strain and even the fast-growing green alga Chlorella vulgaris. Conclusions Metabolic engineering inducing astaxanthin and ketocarotenoids accumulation caused improved high light tolerance and increased biomass productivity in the model species for microalgae Chlamydomonas reinhardtii. Thus, engineering microalgal pigment composition represents a powerful strategy to improve biomass productivities in customized photobioreactors setups. Moreover, engineered astaxanthin accumulation in selected strains could be proposed as a novel strategy to outperform growth of other competing microalgal strains. Supplementary Information The online version contains supplementary material available at 10.1186/s13068-022-02173-3.
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Lee JW, Lee MW, Jin CZ, Oh HM, Jin E, Lee HG. Inhibition of monogalactosyldiacylglycerol synthesis by down-regulation of MGD1 leads to membrane lipid remodeling and enhanced triacylglycerol biosynthesis in Chlamydomonas reinhardtii. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:88. [PMID: 36030272 PMCID: PMC9419350 DOI: 10.1186/s13068-022-02187-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 08/13/2022] [Indexed: 11/10/2022]
Abstract
Abstract
Background
Membrane lipid remodeling involves regulating the physiochemical modification of cellular membranes against abiotic stress or senescence, and it could be a trigger to increase neutral lipid content. In algae and higher plants, monogalactosyldiacylglycerol (MGDG) constitutes the highest proportion of total membrane lipids and is highly reduced as part of the membrane lipid remodeling response under several abiotic stresses. However, genetic regulation of MGDG synthesis and its influence on lipid synthesis has not been studied in microalgae. For development of an industrial microalgae strain showing high accumulation of triacylglycerol (TAG) by promoting membrane lipid remodeling, MGDG synthase 1 (MGD1) down-regulated mutant of Chlamydomonas reinhardtii (Cr-mgd1) was generated and evaluated for its suitability for biodiesel feedstock.
Results
The Cr-mgd1 showed a 65% decrease in CrMGD1 gene expression level, 22% reduction in MGDG content, and 1.39 and 5.40 times increase in diacylglyceryltrimethylhomoserines (DGTS) and TAG, respectively. The expression levels of most genes related to the decomposition of MGDG (plastid galactoglycerolipid degradation1) and TAG metabolism (diacylglycerol O-acyltransferase1, phospholipid:diacylglycerol acyltransferase, and major lipid droplet protein) were increased. The imbalance of DGDG/MGDG ratio in Cr-mgd1 caused reduced photosynthetic electron transport, resulting in less light energy utilization and increased reactive oxygen species levels. In addition, endoplasmic reticulum stress was induced by increased DGTS levels. Thus, accelerated TAG accumulation in Cr-mgd1 was stimulated by increased cellular stress as well as lipid remodeling. Under high light (HL) intensity (400 µmol photons/m2/s), TAG productivity in Cr-mgd1–HL (1.99 mg/L/d) was 2.71 times higher than that in wild type (WT–HL). Moreover, under both nitrogen starvation and high light intensity, the lipid (124.55 mg/L/d), TAG (20.03 mg/L/d), and maximum neutral lipid (56.13 mg/L/d) productivity were the highest.
Conclusions
By inducing lipid remodeling through the mgd1 gene expression regulation, the mutant not only showed high neutral lipid content but also reached the maximum neutral lipid productivity through cultivation under high light and nitrogen starvation conditions, thereby possessing improved biomass properties that are the most suitable for high quality biodiesel production. Thus, this mutant may help understand the role of MGD1 in lipid synthesis in Chlamydomonas and may be used to produce high amounts of TAG.
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12
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Khan KY, Ali B, Zhang S, Stoffella PJ, Shi S, Xia Q, Cui X, Ali Z, Guo Y. Phytotoxic effects on chloroplast and UHPLC-HRMS based untargeted metabolomic responses in Allium tuberosum Rottler ex Sprengel (Chinese leek) exposed to antibiotics. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 234:113418. [PMID: 35304336 DOI: 10.1016/j.ecoenv.2022.113418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 02/24/2022] [Accepted: 03/11/2022] [Indexed: 06/14/2023]
Abstract
Introduction of antibiotics into agricultural fields poses serious health risks to humans. This study investigated the uptake of antibiotics, their effects on metabolic pathways, and chloroplast structure changes of Allium tuberosum exposed to norfloxacin (NFL), oxytetracycline (OTC), and tetracycline (TC). Among all the antibiotic treatments, the highest accumulation of antibiotics in roots (4.15 mg/kg) and leaves (0.29 mg/kg) was TC, while in bulbs it was NFL (5.94 mg/kg). OTC was with the lowest accumulation in roots: 0.19 mg/kg, bulbs: 0.18 mg/kg, and leaves: 0.11 mg/kg. The number of mitochondira and the number of plastoglobulli increased. The chloroplast structure was disturbed under the stress of NFL, OTC, and TC. Disturbance in the chloroplast ultrastructure leads to altered chlorophyll fluorescence variables. Simultaneously, metabolomic profiling of leaves demonstrated that NFL stress regulated more of metabolic pathways than OTC and TC. Differences in metabolic pathways among the antibiotic treatments showed that each antibiotic has different impact even under the same experimental conditions. TC and NFL have more toxic effects than OTC antibiotic. Metabolic variations induced by antibiotics stress highlighted pools of metabolites that affect the metabolic activities, chlorophyll fluorescence, ultrastructural adjustments, and stimulate defensive impact in A. tubersoum. These findings provide an insight of metabolic destabilization as well as metabolic changes in defensive mechanism and stress response of A. tuberosum to different antibiotics.
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Affiliation(s)
- Kiran Yasmin Khan
- Key Laboratory of Advanced Process Control for Light Industry, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Barkat Ali
- The Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; National Agricultural Research Centre, 44000 Islamabad, Pakistan
| | - Shuang Zhang
- The Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Peter Joseph Stoffella
- Indian River Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Fort Pierce, FL 34945, United States
| | - Shiyu Shi
- Dalian Chem Data Solution Information Technology Co. Ltd, Dalian 116000, China
| | - Qian Xia
- Key Laboratory of Advanced Process Control for Light Industry, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Xiaoqiang Cui
- School of Environmental Science and Engineering/Tianjin Key Lab of Biomass Waste Utilization, Tianjin University, Tianjin 300072, China
| | - Zeshan Ali
- Plant Physiology Program, Crop Sciences Institute, National Agricultural Research Centre, Park Road, PO 45500, Islamabad, Pakistan
| | - Ya Guo
- Key Laboratory of Advanced Process Control for Light Industry, Ministry of Education, Jiangnan University, Wuxi 214122, China.
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13
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Akella S, Ma X, Bacova R, Harmer ZP, Kolackova M, Wen X, Wright DA, Spalding MH, Weeks DP, Cerutti H. Co-targeting strategy for precise, scarless gene editing with CRISPR/Cas9 and donor ssODNs in Chlamydomonas. PLANT PHYSIOLOGY 2021; 187:2637-2655. [PMID: 34618092 PMCID: PMC8644747 DOI: 10.1093/plphys/kiab418] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/30/2021] [Indexed: 05/20/2023]
Abstract
Programmable site-specific nucleases, such as the clustered regularly interspaced short palindromic repeat (CRISPR)/ CRISPR-associated protein 9 (Cas9) ribonucleoproteins (RNPs), have allowed creation of valuable knockout mutations and targeted gene modifications in Chlamydomonas (Chlamydomonas reinhardtii). However, in walled strains, present methods for editing genes lacking a selectable phenotype involve co-transfection of RNPs and exogenous double-stranded DNA (dsDNA) encoding a selectable marker gene. Repair of the dsDNA breaks induced by the RNPs is usually accompanied by genomic insertion of exogenous dsDNA fragments, hindering the recovery of precise, scarless mutations in target genes of interest. Here, we tested whether co-targeting two genes by electroporation of pairs of CRISPR/Cas9 RNPs and single-stranded oligodeoxynucleotides (ssODNs) would facilitate the recovery of precise edits in a gene of interest (lacking a selectable phenotype) by selection for precise editing of another gene (creating a selectable marker)-in a process completely lacking exogenous dsDNA. We used PPX1 (encoding protoporphyrinogen IX oxidase) as the generated selectable marker, conferring resistance to oxyfluorfen, and identified precise edits in the homolog of bacterial ftsY or the WD and TetratriCopeptide repeats protein 1 genes in ∼1% of the oxyfluorfen resistant colonies. Analysis of the target site sequences in edited mutants suggested that ssODNs were used as templates for DNA synthesis during homology directed repair, a process prone to replicative errors. The Chlamydomonas acetolactate synthase gene could also be efficiently edited to serve as an alternative selectable marker. This transgene-free strategy may allow creation of individual strains containing precise mutations in multiple target genes, to study complex cellular processes, pathways, or structures.
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Affiliation(s)
- Soujanya Akella
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
| | - Xinrong Ma
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
| | - Romana Bacova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00, Brno, Czech Republic
| | - Zachary P Harmer
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
| | - Martina Kolackova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00, Brno, Czech Republic
| | - Xiaoxue Wen
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
| | - David A Wright
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011, USA
| | - Martin H Spalding
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011, USA
| | - Donald P Weeks
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Heriberto Cerutti
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
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Cecchin M, Jeong J, Son W, Kim M, Park S, Zuliani L, Cazzaniga S, Pompa A, Young Kang C, Bae S, Ballottari M, Jin E. LPA2 protein is involved in photosystem II assembly in Chlamydomonas reinhardtii. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:1648-1662. [PMID: 34218480 PMCID: PMC8518032 DOI: 10.1111/tpj.15405] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 06/23/2021] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
Photosynthetic eukaryotes require the proper assembly of photosystem II (PSII) in order to strip electrons from water and fuel carbon fixation reactions. In Arabidopsis thaliana, one of the PSII subunits (CP43/PsbC) was suggested to be assembled into the PSII complex via its interaction with an auxiliary protein called Low PSII Accumulation 2 (LPA2). However, the original articles describing the role of LPA2 in PSII assembly have been retracted. To investigate the function of LPA2 in the model organism for green algae, Chlamydomonas reinhardtii, we generated knockout lpa2 mutants by using the CRISPR-Cas9 target-specific genome editing system. Biochemical analyses revealed the thylakoidal localization of LPA2 protein in the wild type (WT), whereas lpa2 mutants were characterized by a drastic reduction in the levels of D1, D2, CP47 and CP43 proteins. Consequently, reduced PSII supercomplex accumulation, chlorophyll content per cell, PSII quantum yield and photosynthetic oxygen evolution were measured in the lpa2 mutants, leading to the almost complete impairment of photoautotrophic growth. Pulse-chase experiments demonstrated that the absence of LPA2 protein caused reduced PSII assembly and reduced PSII turnover. Taken together, our data indicate that, in C. reinhardtii, LPA2 is required for PSII assembly and proper function.
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Affiliation(s)
- Michela Cecchin
- Dipartimento di BiotecnologieUniversità di VeronaStrada le Grazie 15Verona37134Italy
| | - Jooyeon Jeong
- Department of Life ScienceHanyang University222, Wangsimni‐ro, Seongdong‐guSeoul04763Korea
| | - Woojae Son
- Department of ChemistryHanyang University222, Wangsimni‐ro, Seongdong‐guSeoul04763Korea
| | - Minjae Kim
- Department of Life ScienceHanyang University222, Wangsimni‐ro, Seongdong‐guSeoul04763Korea
| | - Seunghye Park
- Department of Life ScienceHanyang University222, Wangsimni‐ro, Seongdong‐guSeoul04763Korea
| | - Luca Zuliani
- Dipartimento di BiotecnologieUniversità di VeronaStrada le Grazie 15Verona37134Italy
| | - Stefano Cazzaniga
- Dipartimento di BiotecnologieUniversità di VeronaStrada le Grazie 15Verona37134Italy
| | - Andrea Pompa
- Dipartimento di Scienze BiomolecolariUniversità degli studi di UrbinoVia Aurelio Saffi, 2Urbino61029Italy
- Istituto di Bioscienze e BiorisorseConsiglio Nazionale delle RicercheVia Madonna Alta, 130Perugia06128Italy
| | - Chan Young Kang
- Department of ChemistryHanyang University222, Wangsimni‐ro, Seongdong‐guSeoul04763Korea
| | - Sangsu Bae
- Department of ChemistryHanyang University222, Wangsimni‐ro, Seongdong‐guSeoul04763Korea
| | - Matteo Ballottari
- Dipartimento di BiotecnologieUniversità di VeronaStrada le Grazie 15Verona37134Italy
| | - EonSeon Jin
- Department of Life ScienceHanyang University222, Wangsimni‐ro, Seongdong‐guSeoul04763Korea
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15
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D’Incà E, Cazzaniga S, Foresti C, Vitulo N, Bertini E, Galli M, Gallavotti A, Pezzotti M, Battista Tornielli G, Zenoni S. VviNAC33 promotes organ de-greening and represses vegetative growth during the vegetative-to-mature phase transition in grapevine. THE NEW PHYTOLOGIST 2021; 231:726-746. [PMID: 33567124 PMCID: PMC8251598 DOI: 10.1111/nph.17263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 02/01/2021] [Indexed: 05/08/2023]
Abstract
Plants undergo several developmental transitions during their life cycle. In grapevine, a perennial woody fruit crop, the transition from vegetative/green-to-mature/woody growth involves transcriptomic reprogramming orchestrated by a small group of genes encoding regulators, but the underlying molecular mechanisms are not fully understood. We investigated the function of the transcriptional regulator VviNAC33 by generating and characterizing transgenic overexpressing grapevine lines and a chimeric repressor, and by exploring its putative targets through a DNA affinity purification sequencing (DAP-seq) approach combined with transcriptomic data. We demonstrated that VviNAC33 induces leaf de-greening, inhibits organ growth and directly activates the expression of STAY-GREEN PROTEIN 1 (SGR1), which is involved in Chl and photosystem degradation, and AUTOPHAGY 8f (ATG8f), which is involved in the maturation of autophagosomes. Furthermore, we show that VviNAC33 directly inhibits AUXIN EFFLUX FACILITATOR PIN1, RopGEF1 and ATP SYNTHASE GAMMA CHAIN 1T (ATPC1), which are involved in photosystem II integrity and activity. Our results show that VviNAC33 plays a major role in terminating photosynthetic activity and organ growth as part of a regulatory network governing the vegetative-to-mature phase transition.
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Affiliation(s)
- Erica D’Incà
- Department of BiotechnologyUniversity of VeronaVerona37134Italy
| | | | - Chiara Foresti
- Department of BiotechnologyUniversity of VeronaVerona37134Italy
| | - Nicola Vitulo
- Department of BiotechnologyUniversity of VeronaVerona37134Italy
| | - Edoardo Bertini
- Department of BiotechnologyUniversity of VeronaVerona37134Italy
| | - Mary Galli
- Waksman Institute of MicrobiologyRutgers UniversityPiscatawayNJ08854‐8020USA
| | - Andrea Gallavotti
- Waksman Institute of MicrobiologyRutgers UniversityPiscatawayNJ08854‐8020USA
| | - Mario Pezzotti
- Department of BiotechnologyUniversity of VeronaVerona37134Italy
| | | | - Sara Zenoni
- Department of BiotechnologyUniversity of VeronaVerona37134Italy
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16
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Bassi R, Dall'Osto L. Dissipation of Light Energy Absorbed in Excess: The Molecular Mechanisms. ANNUAL REVIEW OF PLANT BIOLOGY 2021; 72:47-76. [PMID: 34143647 DOI: 10.1146/annurev-arplant-071720-015522] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Light is essential for photosynthesis. Nevertheless, its intensity widely changes depending on time of day, weather, season, and localization of individual leaves within canopies. This variability means that light collected by the light-harvesting system is often in excess with respect to photon fluence or spectral quality in the context of the capacity of photosynthetic metabolism to use ATP and reductants produced from the light reactions. Absorption of excess light can lead to increased production of excited, highly reactive intermediates, which expose photosynthetic organisms to serious risks of oxidative damage. Prevention and management of such stress are performed by photoprotective mechanisms, which operate by cutting down light absorption, limiting the generation of redox-active molecules, or scavenging reactive oxygen species that are released despite the operation of preventive mechanisms. Here, we describe the major physiological and molecular mechanisms of photoprotection involved in the harmless removal of the excess light energy absorbed by green algae and land plants. In vivo analyses of mutants targeting photosynthetic components and the enhanced resolution of spectroscopic techniques have highlighted specific mechanisms protecting the photosynthetic apparatus from overexcitation. Recent findings unveil a network of multiple interacting elements, the reaction times of which vary from a millisecond to weeks, that continuously maintain photosynthetic organisms within the narrow safety range between efficient light harvesting and photoprotection.
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Affiliation(s)
- Roberto Bassi
- Department of Biotechnology, University of Verona, 37134 Verona, Italy;
| | - Luca Dall'Osto
- Department of Biotechnology, University of Verona, 37134 Verona, Italy;
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17
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Troiano JM, Perozeni F, Moya R, Zuliani L, Baek K, Jin E, Cazzaniga S, Ballottari M, Schlau-Cohen GS. Identification of distinct pH- and zeaxanthin-dependent quenching in LHCSR3 from Chlamydomonas reinhardtii. eLife 2021; 10:60383. [PMID: 33448262 PMCID: PMC7864637 DOI: 10.7554/elife.60383] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 01/14/2021] [Indexed: 11/13/2022] Open
Abstract
Under high light, oxygenic photosynthetic organisms avoid photodamage by thermally dissipating absorbed energy, which is called nonphotochemical quenching. In green algae, a chlorophyll and carotenoid-binding protein, light-harvesting complex stress-related (LHCSR3), detects excess energy via a pH drop and serves as a quenching site. Using a combined in vivo and in vitro approach, we investigated quenching within LHCSR3 from Chlamydomonas reinhardtii. In vitro two distinct quenching processes, individually controlled by pH and zeaxanthin, were identified within LHCSR3. The pH-dependent quenching was removed within a mutant LHCSR3 that lacks the residues that are protonated to sense the pH drop. Observation of quenching in zeaxanthin-enriched LHCSR3 even at neutral pH demonstrated zeaxanthin-dependent quenching, which also occurs in other light-harvesting complexes. Either pH- or zeaxanthin-dependent quenching prevented the formation of damaging reactive oxygen species, and thus the two quenching processes may together provide different induction and recovery kinetics for photoprotection in a changing environment. Green plants and algae rely on sunlight to transform light energy into chemical energy in a process known as photosynthesis. However, too much light can damage plants. Green plants prevent this by converting the extra absorbed light into heat. Both the absorption and the dissipation of sunlight into heat occur within so called light harvesting complexes. These are protein structures that contain pigments such as chlorophyll and carotenoids. The process of photoprotection starts when the excess of absorbed light generates protons (elementary particles with a positive charge) faster than they can be used. This causes a change in the pH (a measure of the concentration of protons in a solution), which in turn, modifies the shape of proteins and the chemical identity of the carotenoids. However, it is still unclear what the exact mechanisms are. To clarify this, Troiano, Perozeni et al. engineered the light harvesting complex LHCSR3 of the green algae Chlamydomonas reinhardtii to create mutants that either could not sense changes in the pH or contained the carotenoid zeaxanthin. Zeaxanthin is one of the main carotenoids accumulated by plants and algae upon high light stress. Measurements showed that both pH detection and zeaxanthin were able to provide photoprotection independently. Troiano, Perozeni et al. further found that pH and carotenoids controlled changes to the organisation of the pigment at two separate locations within the LHCSR3, which influenced whether the protein was able to prevent photodamage. When algae were unable to change pH or carotenoids, dissipation was less effective. Instead, specific molecules were produced that damage the cellular machinery. The results shed light onto how green algae protect themselves from too much light exposure. These findings could pave the way for optimising dissipation, which could increase yields of green algae by up to 30%. This could lead to green algae becoming a viable alternative for food, biofuels and feedstock.
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Affiliation(s)
- Julianne M Troiano
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, United States
| | | | - Raymundo Moya
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, United States
| | - Luca Zuliani
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Kwangyrul Baek
- Department of Life Science, Hanyang University, Seoul, Republic of Korea
| | - EonSeon Jin
- Department of Life Science, Hanyang University, Seoul, Republic of Korea
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18
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Perozeni F, Beghini G, Cazzaniga S, Ballottari M. Chlamydomonas reinhardtii LHCSR1 and LHCSR3 proteins involved in photoprotective non-photochemical quenching have different quenching efficiency and different carotenoid affinity. Sci Rep 2020; 10:21957. [PMID: 33319824 PMCID: PMC7738518 DOI: 10.1038/s41598-020-78985-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/02/2020] [Indexed: 11/09/2022] Open
Abstract
Microalgae are unicellular photosynthetic organisms considered as potential alternative sources for biomass, biofuels or high value products. However, their limited biomass productivity represents a bottleneck that needs to be overcome to meet the applicative potential of these organisms. One of the domestication targets for improving their productivity is the proper balance between photoprotection and light conversion for carbon fixation. In the model organism for green algae, Chlamydomonas reinhardtii, a photoprotective mechanism inducing thermal dissipation of absorbed light energy, called Non-photochemical quenching (NPQ), is activated even at relatively low irradiances, resulting in reduced photosynthetic efficiency. Two pigment binding proteins, LHCSR1 and LHCSR3, were previously reported as the main actors during NPQ induction in C. reinhardtii. While previous work characterized in detail the functional properties of LHCSR3, few information is available for the LHCSR1 subunit. Here, we investigated in vitro the functional properties of LHCSR1 and LHCSR3 subunits: despite high sequence identity, the latter resulted as a stronger quencher compared to the former, explaining its predominant role observed in vivo. Pigment analysis, deconvolution of absorption spectra and structural models of LHCSR1 and LHCR3 suggest that different quenching efficiency is related to a different occupancy of L2 carotenoid binding site.
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Affiliation(s)
- Federico Perozeni
- Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134, Verona, Italy
| | - Giorgia Beghini
- Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134, Verona, Italy
| | - Stefano Cazzaniga
- Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134, Verona, Italy
| | - Matteo Ballottari
- Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134, Verona, Italy.
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19
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Cariti F, Chazaux M, Lefebvre-Legendre L, Longoni P, Ghysels B, Johnson X, Goldschmidt-Clermont M. Regulation of Light Harvesting in Chlamydomonas reinhardtii Two Protein Phosphatases Are Involved in State Transitions. PLANT PHYSIOLOGY 2020; 183:1749-1764. [PMID: 32327546 PMCID: PMC7401111 DOI: 10.1104/pp.20.00384] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 04/09/2020] [Indexed: 05/09/2023]
Abstract
Protein phosphorylation plays important roles in short-term regulation of photosynthetic electron transfer, and during state transitions, the kinase STATE TRANSITION7 (STT7) of Chlamydomonas reinhardtii phosphorylates components of light-harvesting antenna complex II (LHCII). This reversible phosphorylation governs the dynamic allocation of a part of LHCII to PSI or PSII, depending on light conditions and metabolic demands, but counteracting phosphatase(s) remain unknown in C. reinhardtii Here we analyzed state transitions in C. reinhardtii mutants of two phosphatases, PROTEIN PHOSPHATASE1 and PHOTOSYSTEM II PHOSPHATASE, which are homologous to proteins that antagonize the state transition kinases (STN7 and STN8) in Arabidopsis (Arabidopsis thaliana). The transition from state 2 to state 1 was retarded in pph1, and surprisingly also in pbcp However, both mutants eventually returned to state 1. In contrast, the double mutant pph1;pbcp appeared strongly locked in state 2. The complex phosphorylation patterns of the LHCII trimers and of the monomeric subunits were affected in the phosphatase mutants. Their analysis indicated that the two phosphatases have different yet overlapping sets of protein targets. The dual control of thylakoid protein dephosphorylation and the more complex antenna phosphorylation patterns in C. reinhardtii compared to Arabidopsis are discussed in the context of the stronger amplitude of state transitions and the more diverse LHCII isoforms in the alga.
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Affiliation(s)
- Federica Cariti
- Department of Botany and Plant Biology, University of Geneva, 1211, Geneva 4, Switzerland
| | - Marie Chazaux
- Aix Marseille University, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Centre National de la Recherche Scientifique, Biosciences and Biotechnologies Institute of Aix-Marseille, F-13108 Saint Paul-Lez-Durance, France
| | | | - Paolo Longoni
- Institute of Genetics and Genomics of Geneva, University of Geneva, 1205 Geneva 4, Switzerland
| | - Bart Ghysels
- Aix Marseille University, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Centre National de la Recherche Scientifique, Biosciences and Biotechnologies Institute of Aix-Marseille, F-13108 Saint Paul-Lez-Durance, France
| | - Xenie Johnson
- Aix Marseille University, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Centre National de la Recherche Scientifique, Biosciences and Biotechnologies Institute of Aix-Marseille, F-13108 Saint Paul-Lez-Durance, France
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20
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Saccon F, Giovagnetti V, Shukla MK, Ruban AV. Rapid regulation of photosynthetic light harvesting in the absence of minor antenna and reaction centre complexes. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:3626-3637. [PMID: 32149343 PMCID: PMC7307847 DOI: 10.1093/jxb/eraa126] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 03/02/2020] [Indexed: 05/25/2023]
Abstract
Plants are subject to dramatic fluctuations in the intensity of sunlight throughout the day. When the photosynthetic machinery is exposed to high light, photons are absorbed in excess, potentially leading to oxidative damage of its delicate membrane components. A photoprotective molecular process called non-photochemical quenching (NPQ) is the fastest response carried out in the thylakoid membranes to harmlessly dissipate excess light energy. Despite having been intensely studied, the site and mechanism of this essential regulatory process are still debated. Here, we show that the main NPQ component called energy-dependent quenching (qE) is present in plants with photosynthetic membranes largely enriched in the major trimeric light-harvesting complex (LHC) II, while being deprived of all minor LHCs and most photosystem core proteins. This fast and reversible quenching depends upon thylakoid lumen acidification (ΔpH). Enhancing ΔpH amplifies the extent of the quenching and restores qE in the membranes lacking PSII subunit S protein (PsbS), whereas the carotenoid zeaxanthin modulates the kinetics and amplitude of the quenching. These findings highlight the self-regulatory properties of the photosynthetic light-harvesting membranes in vivo, where the ability to switch reversibly between the harvesting and dissipative states is an intrinsic property of the major LHCII.
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Affiliation(s)
- Francesco Saccon
- Queen Mary University of London, School of Biological and Chemical Sciences, London, UK
| | - Vasco Giovagnetti
- Queen Mary University of London, School of Biological and Chemical Sciences, London, UK
| | - Mahendra K Shukla
- Queen Mary University of London, School of Biological and Chemical Sciences, London, UK
| | - Alexander V Ruban
- Queen Mary University of London, School of Biological and Chemical Sciences, London, UK
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21
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Colina F, Carbó M, Meijón M, Cañal MJ, Valledor L. Low UV-C stress modulates Chlamydomonas reinhardtii biomass composition and oxidative stress response through proteomic and metabolomic changes involving novel signalers and effectors. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:110. [PMID: 32577129 PMCID: PMC7305600 DOI: 10.1186/s13068-020-01750-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 06/11/2020] [Indexed: 05/06/2023]
Abstract
BACKGROUND The exposure of microalgae and plants to low UV-C radiation dosages can improve their biomass composition and stress tolerance. Despite UV-C sharing these effects with UV-A/B but at much lower dosages, UV-C sensing and signal mechanisms are still mostly unknown. Thus, we have described and integrated the proteometabolomic and physiological changes occurring in Chlamydomonas reinhardtii-a simple Plantae model-into the first 24 h after a short and low-intensity UV-C irradiation in order to reconstruct the microalgae response system to this stress. RESULTS The microalgae response was characterized by increased redox homeostasis, ROS scavenging and protein damage repair/avoidance elements. These processes were upregulated along with others related to the modulation of photosynthetic electron flux, carbon fixation and C/N metabolism. These changes, attributed to either direct UV-C-, ROS- or redox unbalances-associated damage, trigger a response process involving novel signaling intermediaries and effectors such as the translation modulator FAP204, a PP2A-like protein and a novel DYRK kinase. These elements were found linked to the modulation of Chlamydomonas biomass composition (starch accumulation) and proliferation, within an UV-C response probably modulated by different epigenetic factors. CONCLUSION Chosen multiomics integration approach was able to describe many fast changes, including biomass composition and ROS stress tolerance, as a response to a low-intensity UV-C stress. Moreover, the employed omics and systems biology approach placed many previously unidentified protein and metabolites at the center of these changes. These elements would be promising targets for the characterization of this stress response in microalgae and plants and the engineering of more productive microalgae strains.
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Affiliation(s)
- Francisco Colina
- Plant Physiology, Department of Organisms and Systems Biology and University Institute of Biotechnology of Asturias (IUBA), University of Oviedo, Oviedo, Spain
| | - María Carbó
- Plant Physiology, Department of Organisms and Systems Biology and University Institute of Biotechnology of Asturias (IUBA), University of Oviedo, Oviedo, Spain
| | - Mónica Meijón
- Plant Physiology, Department of Organisms and Systems Biology and University Institute of Biotechnology of Asturias (IUBA), University of Oviedo, Oviedo, Spain
| | - María Jesús Cañal
- Plant Physiology, Department of Organisms and Systems Biology and University Institute of Biotechnology of Asturias (IUBA), University of Oviedo, Oviedo, Spain
| | - Luis Valledor
- Plant Physiology, Department of Organisms and Systems Biology and University Institute of Biotechnology of Asturias (IUBA), University of Oviedo, Oviedo, Spain
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