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Huang Y, Xia P. Biomolecular condensates in plant cells: Mediating and integrating environmental signals and development. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2024; 347:112178. [PMID: 38971467 DOI: 10.1016/j.plantsci.2024.112178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 06/23/2024] [Accepted: 06/30/2024] [Indexed: 07/08/2024]
Abstract
In response to the spatiotemporal coordination of various biochemical reactions and membrane-encapsulated organelles, plants appear to provide another effective mechanism for cellular organization by phase separation that allows the internal compartmentalization of cells to form a variety of membrane-less organelles. Most of the research on phase separation has centralized in various non-plant systems, such as yeast and animal systems. Recent studies have shown a remarkable correlation between the formation of condensates in plant systems and the formation of condensates in these systems. Moreover, the last decade has made new advances in phase separation research in the context of plant biology. Here, we provide an overview of the physicochemical forces and molecular factors that drive liquid-liquid phase separation in plant cells and the biochemical characterization of condensates. We then explore new developments in phase separation research specific to plants, discussing examples of condensates found in green plants and detailing their role in plant growth and development. We propose that phase separation may be a conserved organizational mechanism in plant evolution to help plants respond rapidly and effectively to various environmental stresses as sessile organisms.
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Affiliation(s)
- Yang Huang
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Pengguo Xia
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China.
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2
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Liu J, Chen H, Liu L, Meng X, Liu Q, Ye Q, Wen J, Wang T, Dong J. A cargo sorting receptor mediates chloroplast protein trafficking through the secretory pathway. THE PLANT CELL 2024; 36:3770-3786. [PMID: 38963880 PMCID: PMC11371137 DOI: 10.1093/plcell/koae197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 06/05/2024] [Accepted: 06/07/2024] [Indexed: 07/06/2024]
Abstract
Nucleus-encoded chloroplast proteins can be transported via the secretory pathway. The molecular mechanisms underlying the trafficking of chloroplast proteins between the intracellular compartments are largely unclear, and a cargo sorting receptor has not previously been identified in the secretory pathway. Here, we report a cargo sorting receptor that is specifically present in Viridiplantae and mediates the transport of cargo proteins to the chloroplast. Using a forward genetic analysis, we identified a gene encoding a transmembrane protein (MtTP930) in barrel medic (Medicago truncatula). Mutation of MtTP930 resulted in impaired chloroplast function and a dwarf phenotype. MtTP930 is highly expressed in the aerial parts of the plant and is localized to the endoplasmic reticulum (ER) exit sites and Golgi. MtTP930 contains typical cargo sorting receptor motifs, interacts with Sar1, Sec12, and Sec24, and participates in coat protein complex II vesicular transport. Importantly, MtTP930 can recognize the cargo proteins plastidial N-glycosylated nucleotide pyrophosphatase/phosphodiesterase (MtNPP) and α-carbonic anhydrase (MtCAH) in the ER and then transport them to the chloroplast via the secretory pathway. Mutation of a homolog of MtTP930 in Arabidopsis (Arabidopsis thaliana) resulted in a similar dwarf phenotype. Furthermore, MtNPP-GFP failed to localize to chloroplasts when transgenically expressed in Attp930 protoplasts, implying that these cargo sorting receptors are conserved in plants. These findings fill a gap in our understanding of the mechanism by which chloroplast proteins are sorted and transported via the secretory pathway.
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Affiliation(s)
- Jinling Liu
- College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Hong Chen
- College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Li Liu
- College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Xiangzhao Meng
- College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Qianwen Liu
- College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Qinyi Ye
- College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Jiangqi Wen
- Institute for Agricultural Biosciences, Oklahoma State University, Ardmore, OK 73401, USA
- Department of Plant and Soil Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Tao Wang
- College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Jiangli Dong
- College of Biological Sciences, China Agricultural University, Beijing 100193, China
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3
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Nayak N, Mehrotra R, Mehrotra S. The N-region sequence context impacts the chloroplast import efficiency of multi-TMD protein. PLANT MOLECULAR BIOLOGY 2024; 114:88. [PMID: 39093357 DOI: 10.1007/s11103-024-01485-2] [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: 01/15/2024] [Accepted: 07/04/2024] [Indexed: 08/04/2024]
Abstract
Targeting heterologous multi-transmembrane domain (TMD) proteins to plant chloroplasts requires sequences in addition to the chloroplast transit peptide (cTP). The N-terminal domain (N-region), located C-terminal to the cTP in chloroplast inner envelope membrane proteins, is an essential region for import. However, it was unclear if the N-region functions solely as a spacer sequence to facilitate cTP access or if it plays an active role in the import process. This study addresses the N-region's role by using combinations of cTPs and N-regions from Arabidopsis chloroplast inner envelope membrane proteins to direct the cyanobacterial protein SbtA to the chloroplast. We find that the sequence context of the N-region affects the chloroplast import efficiency of SbtA, with particular sequences mis-targeting the protein to different cellular sub-compartments. Additionally, specific cTP and N-region pairs exhibit varying targeting efficiencies for different heterologous proteins. Substituting individual N-region motifs did not significantly alter the chloroplast targeting efficiency of a particular cTP and N-region pair. We conclude that the N-region exhibits contextual functioning and potentially functional redundancy in motifs.
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Affiliation(s)
- Namitha Nayak
- Department of Biological Sciences, Birla Institute of Science and Technology- K. K. Birla Goa Campus, Sancoale, Goa, India
| | - Rajesh Mehrotra
- Department of Biological Sciences, Birla Institute of Science and Technology- K. K. Birla Goa Campus, Sancoale, Goa, India
| | - Sandhya Mehrotra
- Department of Biological Sciences, Birla Institute of Science and Technology- K. K. Birla Goa Campus, Sancoale, Goa, India.
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4
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K. Raval P, MacLeod AI, Gould SB. A molecular atlas of plastid and mitochondrial proteins reveals organellar remodeling during plant evolutionary transitions from algae to angiosperms. PLoS Biol 2024; 22:e3002608. [PMID: 38713727 PMCID: PMC11135702 DOI: 10.1371/journal.pbio.3002608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 05/29/2024] [Accepted: 03/28/2024] [Indexed: 05/09/2024] Open
Abstract
Algae and plants carry 2 organelles of endosymbiotic origin that have been co-evolving in their host cells for more than a billion years. The biology of plastids and mitochondria can differ significantly across major lineages and organelle changes likely accompanied the adaptation to new ecological niches such as the terrestrial habitat. Based on organelle proteome data and the genomes of 168 phototrophic (Archaeplastida) versus a broad range of 518 non-phototrophic eukaryotes, we screened for changes in plastid and mitochondrial biology across 1 billion years of evolution. Taking into account 331,571 protein families (or orthogroups), we identify 31,625 protein families that are unique to primary plastid-bearing eukaryotes. The 1,906 and 825 protein families are predicted to operate in plastids and mitochondria, respectively. Tracing the evolutionary history of these protein families through evolutionary time uncovers the significant remodeling the organelles experienced from algae to land plants. The analyses of gained orthogroups identifies molecular changes of organelle biology that connect to the diversification of major lineages and facilitated major transitions from chlorophytes en route to the global greening and origin of angiosperms.
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Affiliation(s)
- Parth K. Raval
- Institute for Molecular Evolution, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Alexander I. MacLeod
- Institute for Molecular Evolution, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Sven B. Gould
- Institute for Molecular Evolution, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
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5
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Sharma M, Abt MR, Eicke S, Ilse TE, Liu C, Lucas MS, Pfister B, Zeeman SC. MFP1 defines the subchloroplast location of starch granule initiation. Proc Natl Acad Sci U S A 2024; 121:e2309666121. [PMID: 38190535 PMCID: PMC10801857 DOI: 10.1073/pnas.2309666121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 12/07/2023] [Indexed: 01/10/2024] Open
Abstract
Starch is one of the major carbohydrate storage compounds in plants. The biogenesis of starch granules starts with the formation of initials, which subsequently expand into granules. Several coiled-coil domain-containing proteins have been previously implicated with the initiation process, but the mechanisms by which they act remain largely elusive. Here, we demonstrate that one of these proteins, the thylakoid-associated MAR-BINDING FILAMENT-LIKE PROTEIN 1 (MFP1), specifically determines the subchloroplast location of initial formation. The expression of MFP1 variants "mis"-targeted to specific locations within chloroplasts in Arabidopsis results in distinctive shifts in not only how many but also where starch granules are formed. Importantly, "re" localizing MFP1 to the stromal face of the chloroplast's inner envelope is sufficient to generate starch granules in this aberrant position. These findings provide compelling evidence that a single protein MFP1 possesses the capacity to direct the initiation and biosynthesis machinery of starch granules.
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Affiliation(s)
- Mayank Sharma
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Melanie R Abt
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Simona Eicke
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Theresa E Ilse
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Chun Liu
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Miriam S Lucas
- Scientific Center for Optical and Electron Microscopy, ETH Zurich, 8093 Zurich, Switzerland
| | - Barbara Pfister
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Samuel C Zeeman
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
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6
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Guo Y, Li Q, Ji D, Tian L, Meurer J, Chi W. A Ubiquitin-Based Module Directing Protein-Protein Interactions in Chloroplasts. Int J Mol Sci 2023; 24:16673. [PMID: 38068997 PMCID: PMC10706609 DOI: 10.3390/ijms242316673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/18/2023] [Accepted: 11/21/2023] [Indexed: 12/18/2023] Open
Abstract
A promising approach for the genetic engineering of multiprotein complexes in living cells involves designing and reconstructing the interaction between two proteins that lack native affinity. Thylakoid-embedded multiprotein complexes execute the light reaction of plant photosynthesis, but their engineering remains challenging, likely due to difficulties in accurately targeting heterologous membrane-bound proteins to various sub-compartments of thylakoids. In this study, we developed a ubiquitin-based module (Nub-Cub) capable of directing interactions in vivo between two chloroplast proteins lacking native affinities. We applied this module to genetically modify thylakoid multiprotein complexes. We demonstrated the functionality of the Nub-Cub module in the model organism Arabidopsis thaliana. Employing this system, we successfully modified the Photosystem II (PSII) complex by ectopically attaching an extrinsic subunit of PSII, PsbTn1, to CP26-a component of the antenna system of PSII. Surprisingly, this mandatory interaction between CP26 and PsbTn1 in plants impairs the efficiency of electron transport in PSII and unexpectedly results in noticeable defects in leaf development. Our study not only offers a general strategy to modify multiprotein complexes embedded in thylakoid membranes but it also sheds light on the possible interplay between two proteins without native interaction.
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Affiliation(s)
- Yinjie Guo
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; (Y.G.); (Q.L.); (D.J.); (L.T.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiuxin Li
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; (Y.G.); (Q.L.); (D.J.); (L.T.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Daili Ji
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; (Y.G.); (Q.L.); (D.J.); (L.T.)
| | - Lijin Tian
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; (Y.G.); (Q.L.); (D.J.); (L.T.)
| | - Jörg Meurer
- Faculty of Biology, Plant Molecular Biology, Ludwig-Maximilians University, D-82152 Munich, Germany;
| | - Wei Chi
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; (Y.G.); (Q.L.); (D.J.); (L.T.)
- University of Chinese Academy of Sciences, Beijing 100049, China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China
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Nellaepalli S, Lau AS, Jarvis RP. Chloroplast protein translocation pathways and ubiquitin-dependent regulation at a glance. J Cell Sci 2023; 136:jcs241125. [PMID: 37732520 PMCID: PMC10546890 DOI: 10.1242/jcs.241125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023] Open
Abstract
Chloroplasts conduct photosynthesis and numerous metabolic and signalling processes that enable plant growth and development. Most of the ∼3000 proteins in chloroplasts are nucleus encoded and must be imported from the cytosol. Thus, the protein import machinery of the organelle (the TOC-TIC apparatus) is of fundamental importance for chloroplast biogenesis and operation. Cytosolic factors target chloroplast precursor proteins to the TOC-TIC apparatus, which drives protein import across the envelope membranes into the organelle, before various internal systems mediate downstream routing to different suborganellar compartments. The protein import system is proteolytically regulated by the ubiquitin-proteasome system (UPS), enabling centralized control over the organellar proteome. In addition, the UPS targets a range of chloroplast proteins directly. In this Cell Science at a Glance article and the accompanying poster, we present mechanistic details of these different chloroplast protein targeting and translocation events, and of the UPS systems that regulate chloroplast proteins.
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Affiliation(s)
- Sreedhar Nellaepalli
- Section of Molecular Plant Biology, Department of Biology, University of Oxford, Oxford OX1 3RB, UK
| | - Anne Sophie Lau
- Section of Molecular Plant Biology, Department of Biology, University of Oxford, Oxford OX1 3RB, UK
- Department of Plant Physiology, Faculty of Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - R. Paul Jarvis
- Section of Molecular Plant Biology, Department of Biology, University of Oxford, Oxford OX1 3RB, UK
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An H, Ke X, Li L, Liu Y, Yuan S, Wang Q, Hou X, Zhao J. ALBINO EMBRYO AND SEEDLING is required for RNA splicing and chloroplast homeostasis in Arabidopsis. PLANT PHYSIOLOGY 2023; 193:483-501. [PMID: 37311175 DOI: 10.1093/plphys/kiad341] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 05/03/2023] [Accepted: 05/07/2023] [Indexed: 06/15/2023]
Abstract
Pentatricopeptide repeat (PPR) proteins form a large protein family and have diverse functions in plant development. Here, we identified an ALBINO EMBRYO AND SEEDLING (AES) gene that encodes a P-type PPR protein expressed in various tissues, especially the young leaves of Arabidopsis (Arabidopsis thaliana). Its null mutant aes exhibited a collapsed chloroplast membrane system, reduced pigment content and photosynthetic activity, decreased transcript levels of PEP (plastid-encoded polymerase)-dependent chloroplast genes, and defective RNA splicing. Further work revealed that AES could directly bind to psbB-psbT, psbH-petB, rps8-rpl36, clpP, ycf3, and ndhA in vivo and in vitro and that the splicing efficiencies of these genes and the expression levels of ycf3, ndhA, and cis-tron psbB-psbT-psbH-petB-petD decreased dramatically, leading to defective PSI, PSII, and Cyt b6f in aes. Moreover, AES could be transported into the chloroplast stroma via the TOC-TIC channel with the assistance of Tic110 and cpSRP54 and may recruit HCF244, SOT1, and CAF1 to participate in the target RNA process. These findings suggested that AES is an essential protein for the assembly of photosynthetic complexes, providing insights into the splicing of psbB operon (psbB-psbT-psbH-petB-petD), ycf3, and ndhA, as well as maintaining chloroplast homeostasis.
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Affiliation(s)
- Hongqiang An
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, 430072 Wuhan, China
| | - Xiaolong Ke
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, 430072 Wuhan, China
| | - Lu Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, 430072 Wuhan, China
| | - Yantong Liu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, 430072 Wuhan, China
| | - Sihui Yuan
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, 430072 Wuhan, China
| | - Qiuyu Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, 430072 Wuhan, China
| | - Xin Hou
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, 430072 Wuhan, China
| | - Jie Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, 430072 Wuhan, China
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Yu JS, You MK, Lee YJ, Ha SH. Stepwise protein targeting into plastoglobules are facilitated by three hydrophobic regions of rice phytoene synthase 2. FRONTIERS IN PLANT SCIENCE 2023; 14:1181311. [PMID: 37324722 PMCID: PMC10264786 DOI: 10.3389/fpls.2023.1181311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/10/2023] [Indexed: 06/17/2023]
Abstract
Plastoglobules (PGs) are plastidial lipid droplets enclosed by a polar monolayer born from the thylakoid membrane when plants require active lipid metabolism, including carotenogenesis, under the environmental stress and during plastid transition. Despite the fact that many proteins are reported to target PGs, their translocation mechanism has remained largely unexplored. To elucidate this process, we studied the influence of three hydrophobic regions (HR)-HR1 (1-45th aa), HR2 (46-80th aa), and HR3 (229-247th aa)-of rice phytoene synthase 2 (OsPSY2, 398 aa), which has previously shown to target PGs. As results, HR1 includes the crucial sequence (31-45th aa) for chloroplast import and the stromal cleavage occurs at a specific alanine site (64th aa) within HR2, verifying that a N-terminal 64-aa-region works as the transit peptide (Tp). HR2 has a weak PG-targeting signal by showing synchronous and asynchronous localization patterns in both PGs and stroma of chloroplasts. HR3 exhibited a strong PG-targeting role with the required positional specificity to prevent potential issues such as non-accumulation, aggregation, and folding errors in proteins. Herein, we characterized a Tp and two transmembrane domains in three HRs of OsPSY2 and propose a spontaneous pathway for its PG-translocation with a shape embedded in the PG-monolayer. Given this subplastidial localization, we suggest six sophisticated tactics for plant biotechnology applications, including metabolic engineering and molecular farming.
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Zhang T, Dong X, Yuan X, Hong Y, Zhang L, Zhang X, Chen S. Identification and characterization of CsSRP43, a major gene controlling leaf yellowing in cucumber. HORTICULTURE RESEARCH 2022; 9:uhac212. [PMID: 36479584 PMCID: PMC9719040 DOI: 10.1093/hr/uhac212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 09/14/2022] [Indexed: 06/17/2023]
Abstract
Mutants are crucial to extending our understanding of genes and their functions in higher plants. In this study a spontaneous cucumber mutant, yf, showed yellow color leaves, had significant decreases in related physiological indexes of photosynthesis characteristics, and had more abnormal chloroplasts and thylakoids. Inheritance analysis indicated that the yellow color of the leaf was controlled by a recessive nuclear locus, yf. A candidate gene, CsSRP43, encoding a chloroplast signal recognition particle 43 protein, was identified through map-based cloning and whole-genome sequence analysis. Alignment of the CsSRP43 gene homologs between both parental lines revealed a 7-kb deletion mutation including the promoter region and the coding sequence in the yf mutant. In order to determine if the CsSRP43 gene was involved in the formation of leaf color, the CRISPR/Cas9-mediate system was used to modify CsSRP43 in the 9930 background; two independent transgenic lines, srp43-1 and srp43-2, were generated, and they showed yellow leaves with abnormal chloroplasts and thylakoids. Transcriptomic analysis revealed that differentially expressed genes associated with the photosynthesis-related pathway were highly enriched between srp43-1 and wild type, most of which were significantly downregulated in line srp43-1. Furthermore, yeast two-hybrid and biomolecular fluorescence complementation assays were used to confirm that CsSRP43 directly interacted with LHCP and cpSRP54 proteins. A model was established to explain the molecular mechanisms by which CsSRP43 participates in the leaf color and photosynthesis pathway, and it provides a valuable basis for understanding the molecular and genetic mechanisms of leaf color in cucumber.
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Affiliation(s)
- Tingting Zhang
- College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China
- Shaanxi Engineering Research Center for Vegetables, Yangling 712100, China
| | - Xiangyu Dong
- College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China
- Shaanxi Engineering Research Center for Vegetables, Yangling 712100, China
| | - Xin Yuan
- College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China
- Shaanxi Engineering Research Center for Vegetables, Yangling 712100, China
| | - Yuanyuan Hong
- College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China
- Shaanxi Engineering Research Center for Vegetables, Yangling 712100, China
| | - Lingling Zhang
- College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China
- Shaanxi Engineering Research Center for Vegetables, Yangling 712100, China
| | - Xuan Zhang
- College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China
- Shaanxi Engineering Research Center for Vegetables, Yangling 712100, China
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11
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MacLeod AI, Raval PK, Stockhorst S, Knopp MR, Frangedakis E, Gould SB. Loss of Plastid Developmental Genes Coincides With a Reversion to Monoplastidy in Hornworts. FRONTIERS IN PLANT SCIENCE 2022; 13:863076. [PMID: 35360315 PMCID: PMC8964177 DOI: 10.3389/fpls.2022.863076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
The first plastid evolved from an endosymbiotic cyanobacterium in the common ancestor of the Archaeplastida. The transformative steps from cyanobacterium to organelle included the transfer of control over developmental processes, a necessity for the host to orchestrate, for example, the fission of the organelle. The plastids of almost all embryophytes divide independently from nuclear division, leading to cells housing multiple plastids. Hornworts, however, are monoplastidic (or near-monoplastidic), and their photosynthetic organelles are a curious exception among embryophytes for reasons such as the occasional presence of pyrenoids. In this study, we screened genomic and transcriptomic data of eleven hornworts for components of plastid developmental pathways. We found intriguing differences among hornworts and specifically highlight that pathway components involved in regulating plastid development and biogenesis were differentially lost in this group of bryophytes. Our results also confirmed that hornworts underwent significant instances of gene loss, underpinning that the gene content of this group is significantly lower than other bryophytes and tracheophytes. In combination with ancestral state reconstruction, our data suggest that hornworts have reverted back to a monoplastidic phenotype due to the combined loss of two plastid division-associated genes, namely, ARC3 and FtsZ2.
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Affiliation(s)
- Alexander I. MacLeod
- Institute for Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Parth K. Raval
- Institute for Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Simon Stockhorst
- Institute for Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Michael R. Knopp
- Institute for Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | | | - Sven B. Gould
- Institute for Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
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12
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Zhu D, Xiong H, Wu J, Zheng C, Lu D, Zhang L, Xu X. Protein Targeting Into the Thylakoid Membrane Through Different Pathways. Front Physiol 2022; 12:802057. [PMID: 35095563 PMCID: PMC8790069 DOI: 10.3389/fphys.2021.802057] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 12/07/2021] [Indexed: 01/19/2023] Open
Abstract
In higher plants, chloroplasts are essential semi-autonomous organelles with complex compartments. As part of these sub-organellar compartments, the sheet-like thylakoid membranes contain abundant light-absorbing chlorophylls bound to the light-harvesting proteins and to some of the reaction center proteins. About half of the thylakoid membrane proteins are encoded by nuclear genes and synthesized in the cytosol as precursors before being imported into the chloroplast. After translocation across the chloroplast envelope by the Toc/Tic system, these proteins are subsequently inserted into or translocated across the thylakoid membranes through distinct pathways. The other half of thylakoid proteins are encoded by the chloroplast genome, synthesized in the stroma and integrated into the thylakoid through a cotranslational process. Much progress has been made in identification and functional characterization of new factors involved in protein targeting into the thylakoids, and new insights into this process have been gained. In this review, we introduce the distinct transport systems mediating the translocation of substrate proteins from chloroplast stroma to the thylakoid membrane, and present the recent advances in the identification of novel components mediating these pathways. Finally, we raise some unanswered questions involved in the targeting of chloroplast proteins into the thylakoid membrane, along with perspectives for future research.
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Affiliation(s)
- Dan Zhu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Haibo Xiong
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Jianghao Wu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Canhui Zheng
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Dandan Lu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Lixin Zhang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Xiumei Xu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
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13
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Hegde RS, Keenan RJ. The mechanisms of integral membrane protein biogenesis. Nat Rev Mol Cell Biol 2022; 23:107-124. [PMID: 34556847 DOI: 10.1038/s41580-021-00413-2] [Citation(s) in RCA: 84] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2021] [Indexed: 02/08/2023]
Abstract
Roughly one quarter of all genes code for integral membrane proteins that are inserted into the plasma membrane of prokaryotes or the endoplasmic reticulum membrane of eukaryotes. Multiple pathways are used for the targeting and insertion of membrane proteins on the basis of their topological and biophysical characteristics. Multipass membrane proteins span the membrane multiple times and face the additional challenges of intramembrane folding. In many cases, integral membrane proteins require assembly with other proteins to form multi-subunit membrane protein complexes. Recent biochemical and structural analyses have provided considerable clarity regarding the molecular basis of membrane protein targeting and insertion, with tantalizing new insights into the poorly understood processes of multipass membrane protein biogenesis and multi-subunit protein complex assembly.
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Affiliation(s)
- Ramanujan S Hegde
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, UK.
| | - Robert J Keenan
- Gordon Center for Integrative Science, The University of Chicago, Chicago, IL, USA.
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14
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Zheng C, Xu X, Zhang L, Lu D. Liquid-Liquid Phase Separation Phenomenon on Protein Sorting Within Chloroplasts. Front Physiol 2022; 12:801212. [PMID: 35002776 PMCID: PMC8740050 DOI: 10.3389/fphys.2021.801212] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 12/09/2021] [Indexed: 12/13/2022] Open
Abstract
In higher plants, chloroplasts are vital organelles possessing highly complex compartmentalization. As most chloroplast-located proteins are encoded in the nucleus and synthesized in the cytosol, the correct sorting of these proteins to appropriate compartments is critical for the proper functions of chloroplasts as well as plant survival. Nuclear-encoded chloroplast proteins are imported into stroma and further sorted to distinct compartments via different pathways. The proteins predicted to be sorted to the thylakoid lumen by the chloroplast twin arginine transport (cpTAT) pathway are shown to be facilitated by STT1/2 driven liquid-liquid phase separation (LLPS). Liquid-liquid phase separation is a novel mechanism to facilitate the formation of membrane-less sub-cellular compartments and accelerate biochemical reactions temporally and spatially. In this review, we introduce the sorting mechanisms within chloroplasts, and briefly summarize the properties and significance of LLPS, with an emphasis on the novel function of LLPS in the sorting of cpTAT substrate proteins. We conclude with perspectives for the future research on chloroplast protein sorting and targeting mechanisms.
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Affiliation(s)
- Canhui Zheng
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Xiumei Xu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Lixin Zhang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Dandan Lu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
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15
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Ji M, Zhao J, Han K, Cui W, Wu X, Chen B, Lu Y, Peng J, Zheng H, Rao S, Wu G, Chen J, Yan F. Turnip mosaic virus P1 suppresses JA biosynthesis by degrading cpSRP54 that delivers AOCs onto the thylakoid membrane to facilitate viral infection. PLoS Pathog 2021; 17:e1010108. [PMID: 34852025 PMCID: PMC8668097 DOI: 10.1371/journal.ppat.1010108] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 12/13/2021] [Accepted: 11/11/2021] [Indexed: 11/18/2022] Open
Abstract
Jasmonic acid (JA) is a crucial hormone in plant antiviral immunity. Increasing evidence shows that viruses counter this host immune response by interfering with JA biosynthesis and signaling. However, the mechanism by which viruses affect JA biosynthesis is still largely unexplored. Here, we show that a highly conserved chloroplast protein cpSRP54 was downregulated in Nicotiana benthamiana infected by turnip mosaic virus (TuMV). Its silencing facilitated TuMV infection. Furthermore, cpSRP54 interacted with allene oxide cyclases (AOCs), key JA biosynthesis enzymes, and was responsible for delivering AOCs onto the thylakoid membrane (TM). Interestingly, TuMV P1 protein interacted with cpSRP54 and mediated its degradation via the 26S proteosome and autophagy pathways. The results suggest that TuMV has evolved a strategy, through the inhibition of cpSRP54 and its delivery of AOCs to the TM, to suppress JA biosynthesis and enhance viral infection. Interaction between cpSRP54 and AOCs was shown to be conserved in Arabidopsis and rice, while cpSRP54 also interacted with, and was degraded by, pepper mild mottle virus (PMMoV) 126 kDa protein and potato virus X (PVX) p25 protein, indicating that suppression of cpSRP54 may be a common mechanism used by viruses to counter the antiviral JA pathway. Jasmonic acid pathway has emerged as one of the predominant battlefields between plants and viruses. Several studies have indicated that, in addition to interfering with JA signaling, plant viruses can also affect JA biosynthesis, but the direct molecular links between them remain elusive. Here, we identify a highly conserved chloroplast protein cpSRP54 as a key positive regulator in JA biosynthesis and a common target for viruses belong to different genera. Through associating with cpSRP54 and inducing its degradation using the protein they encoded, the viruses can inhibit the cpSRP54-facilitated delivery of AOCs to the thylakoid membrane and manipulation of JA-mediated defense. This capability of viruses might define a novel and effective strategy against the antiviral JA pathway.
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Affiliation(s)
- Mengfei Ji
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
- Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Jinping Zhao
- Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Kelei Han
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Weijun Cui
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Xinyang Wu
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Binghua Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Yuwen Lu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
- Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Jiejun Peng
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
- Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Hongying Zheng
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
- Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Shaofei Rao
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
- Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Guanwei Wu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
- Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Jianping Chen
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
- Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
- * E-mail: (JC); (FY)
| | - Fei Yan
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
- Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
- * E-mail: (JC); (FY)
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16
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Xu X, Zheng C, Lu D, Song CP, Zhang L. Phase separation in plants: New insights into cellular compartmentalization. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2021; 63:1835-1855. [PMID: 34314106 DOI: 10.1111/jipb.13152] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 07/16/2021] [Indexed: 05/16/2023]
Abstract
A fundamental challenge for cells is how to coordinate various biochemical reactions in space and time. To achieve spatiotemporal control, cells have developed organelles that are surrounded by lipid bilayer membranes. Further, membraneless compartmentalization, a process induced by dynamic physical association of biomolecules through phase transition offers another efficient mechanism for intracellular organization. While our understanding of phase separation was predominantly dependent on yeast and animal models, recent findings have provided compelling evidence for emerging roles of phase separation in plants. In this review, we first provide an overview of the current knowledge of phase separation, including its definition, biophysical principles, molecular features and regulatory mechanisms. Then we summarize plant-specific phase separation phenomena and describe their functions in plant biological processes in great detail. Moreover, we propose that phase separation is an evolutionarily conserved and efficient mechanism for cellular compartmentalization which allows for distinct metabolic processes and signaling pathways, and is especially beneficial for the sessile lifestyle of plants to quickly and efficiently respond to the changing environment.
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Affiliation(s)
- Xiumei Xu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Canhui Zheng
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Dandan Lu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Chun-Peng Song
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Lixin Zhang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
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17
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Rottet S, Förster B, Hee WY, Rourke LM, Price GD, Long BM. Engineered Accumulation of Bicarbonate in Plant Chloroplasts: Known Knowns and Known Unknowns. FRONTIERS IN PLANT SCIENCE 2021; 12:727118. [PMID: 34531888 PMCID: PMC8438413 DOI: 10.3389/fpls.2021.727118] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 08/06/2021] [Indexed: 05/10/2023]
Abstract
Heterologous synthesis of a biophysical CO2-concentrating mechanism (CCM) in plant chloroplasts offers significant potential to improve the photosynthetic efficiency of C3 plants and could translate into substantial increases in crop yield. In organisms utilizing a biophysical CCM, this mechanism efficiently surrounds a high turnover rate Rubisco with elevated CO2 concentrations to maximize carboxylation rates. A critical feature of both native biophysical CCMs and one engineered into a C3 plant chloroplast is functional bicarbonate (HCO3 -) transporters and vectorial CO2-to-HCO3 - converters. Engineering strategies aim to locate these transporters and conversion systems to the C3 chloroplast, enabling elevation of HCO3 - concentrations within the chloroplast stroma. Several CCM components have been identified in proteobacteria, cyanobacteria, and microalgae as likely candidates for this approach, yet their successful functional expression in C3 plant chloroplasts remains elusive. Here, we discuss the challenges in expressing and regulating functional HCO3 - transporter, and CO2-to-HCO3 - converter candidates in chloroplast membranes as an essential step in engineering a biophysical CCM within plant chloroplasts. We highlight the broad technical and physiological concerns which must be considered in proposed engineering strategies, and present our current status of both knowledge and knowledge-gaps which will affect successful engineering outcomes.
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Affiliation(s)
- Sarah Rottet
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, Canberra, ACT, Australia
| | - Britta Förster
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Wei Yih Hee
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, Canberra, ACT, Australia
| | - Loraine M. Rourke
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, Canberra, ACT, Australia
| | - G. Dean Price
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, Canberra, ACT, Australia
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Benedict M. Long
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, Canberra, ACT, Australia
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Canberra, ACT, Australia
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