1
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Wada M, Higa T, Katoh K, Moritoki N, Nakai T, Nishino Y, Miyazawa A, Shibata S, Mineyuki Y. Chloroplast-actin filaments decide the direction of chloroplast avoidance movement under strong light in Arabidopsis thaliana. JOURNAL OF PLANT RESEARCH 2024:10.1007/s10265-024-01540-5. [PMID: 38598067 DOI: 10.1007/s10265-024-01540-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 03/14/2024] [Indexed: 04/11/2024]
Abstract
Chloroplast-actin (cp-actin) filaments are crucial for light-induced chloroplast movement, and appear in the front region of moving chloroplasts when visualized using GFP-mouse Talin. They are short and thick, exist between a chloroplast and the plasma membrane, and move actively and rapidly compared to cytoplasmic long actin filaments that run through a cell. The average period during which a cp-actin filament was observed at the same position was less than 0.5 s. The average lengths of the cp-actin filaments calculated from those at the front region of the moving chloroplast and those around the chloroplast periphery after stopping the movement were almost the same, approximately 0.8 µm. Each cp-actin filament is shown as a dotted line consisting of 4-5 dots. The vector sum of cp-actin filaments in a moving chloroplast is parallel to the moving direction of the chloroplast, suggesting that the direction of chloroplast movement is regulated by the vector sum of cp-actin filaments. However, once the chloroplasts stopped moving, the vector sum of the cp-actin filaments around the chloroplast periphery was close to zero, indicating that the direction of movement was undecided. To determine the precise structure of cp-actin filaments under electron microscopy, Arabidopsis leaves and fern Adiantum capillus-veneris gametophytes were frozen using a high-pressure freezer, and observed under electron microscopy. However, no bundled microfilaments were found, suggesting that the cp-actin filaments were unstable even under high-pressure freezing.
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Grants
- 16K14758 Ohsumi Frontier Science Foundation
- 20227001 the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT)/the Japan Society for the Promotion of Science (JSPS)
- 23120523 the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT)/the Japan Society for the Promotion of Science (JSPS)
- 25120721 the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT)/the Japan Society for the Promotion of Science (JSPS)
- 25251033 the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT)/the Japan Society for the Promotion of Science (JSPS)
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Affiliation(s)
- Masamitsu Wada
- Graduate School of Science, Tokyo Metropolitan University, Tokyo, 192-0397, Japan.
- , Kamikitazawa 3-25-7, Setagaya-Ku, Tokyo, 156-0057, Japan.
| | - Takeshi Higa
- Graduate School of Science, Tokyo Metropolitan University, Tokyo, 192-0397, Japan
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, 153-8902, Japan
| | - Kaoru Katoh
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki, 305-8562, Japan
| | - Nobuko Moritoki
- Electron Microscope Laboratory, Keio University School of Medicine, Tokyo, 160-8582, Japan
| | - Tomonori Nakai
- Graduate School of Science, University of Hyogo, Hyogo, 671-2280, Japan
| | - Yuri Nishino
- Graduate School of Science, University of Hyogo, Hyogo, 678-1297, Japan
| | - Atsuo Miyazawa
- Graduate School of Science, University of Hyogo, Hyogo, 678-1297, Japan
| | - Shinsuke Shibata
- Electron Microscope Laboratory, Keio University School of Medicine, Tokyo, 160-8582, Japan
- Division of Microscopic Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, 951-8510, Japan
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2
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Kakoulidou I, Piecyk RS, Meyer RC, Kuhlmann M, Gutjahr C, Altmann T, Johannes F. Mapping parental DMRs predictive of local and distal methylome remodeling in epigenetic F1 hybrids. Life Sci Alliance 2024; 7:e202402599. [PMID: 38290756 PMCID: PMC10828516 DOI: 10.26508/lsa.202402599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 01/21/2024] [Accepted: 01/22/2024] [Indexed: 02/01/2024] Open
Abstract
F1 hybrids derived from a cross between two inbred parental lines often display widespread changes in DNA methylation and gene expression patterns relative to their parents. An emerging challenge is to understand how parental epigenomic differences contribute to these events. Here, we generated a large mapping panel of F1 epigenetic hybrids, whose parents are isogenic but variable in their DNA methylation patterns. Using a combination of multi-omic profiling and epigenetic mapping strategies we show that differentially methylated regions in parental pericentromeres act as major reorganizers of hybrid methylomes and transcriptomes, even in the absence of genetic variation. These parental differentially methylated regions are associated with hybrid methylation remodeling events at thousands of target regions throughout the genome, both locally (in cis) and distally (in trans). Many of these distally-induced methylation changes lead to nonadditive expression of nearby genes and associate with phenotypic heterosis. Our study highlights the pleiotropic potential of parental pericentromeres in the functional remodeling of hybrid genomes and phenotypes.
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Affiliation(s)
- Ioanna Kakoulidou
- https://ror.org/02kkvpp62 Plant Epigenomics, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Munich, Germany
| | - Robert S Piecyk
- https://ror.org/02kkvpp62 Plant Epigenomics, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Munich, Germany
| | - Rhonda C Meyer
- https://ror.org/02skbsp27 Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Markus Kuhlmann
- https://ror.org/02skbsp27 Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Caroline Gutjahr
- Plant Genetics, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Thomas Altmann
- https://ror.org/02skbsp27 Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Frank Johannes
- https://ror.org/02kkvpp62 Plant Epigenomics, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Munich, Germany
- https://ror.org/02kkvpp62 Institute of Advanced Studies, Technical University of Munich, Munich, Germany
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3
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The SV, Santiago JP, Pappenberger C, Hammes UZ, Tegeder M. UMAMIT44 is a key player in glutamate export from Arabidopsis chloroplasts. THE PLANT CELL 2024; 36:1119-1139. [PMID: 38092462 PMCID: PMC10980354 DOI: 10.1093/plcell/koad310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 11/15/2023] [Indexed: 04/01/2024]
Abstract
Selective partitioning of amino acids among organelles, cells, tissues, and organs is essential for cellular metabolism and plant growth. Nitrogen assimilation into glutamine and glutamate and de novo biosynthesis of most protein amino acids occur in chloroplasts; therefore, various transport mechanisms must exist to accommodate their directional efflux from the stroma to the cytosol and feed the amino acids into the extraplastidial metabolic and long-distance transport pathways. Yet, Arabidopsis (Arabidopsis thaliana) transporters functioning in plastidial export of amino acids remained undiscovered. Here, USUALLY MULTIPLE ACIDS MOVE IN AND OUT TRANSPORTER 44 (UMAMIT44) was identified and shown to function in glutamate export from Arabidopsis chloroplasts. UMAMIT44 controls glutamate homeostasis within and outside of chloroplasts and influences nitrogen partitioning from leaves to sinks. Glutamate imbalances in chloroplasts and leaves of umamit44 mutants impact cellular redox state, nitrogen and carbon metabolism, and amino acid (AA) and sucrose supply of growing sinks, leading to negative effects on plant growth. Nonetheless, the mutant lines adjust to some extent by upregulating alternative pathways for glutamate synthesis outside the plastids and by mitigating oxidative stress through the production of other amino acids and antioxidants. Overall, this study establishes that the role of UMAMIT44 in glutamate export from chloroplasts is vital for controlling nitrogen availability within source leaf cells and for sink nutrition, with an impact on growth and seed yield.
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Affiliation(s)
- Samantha Vivia The
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - James P Santiago
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Clara Pappenberger
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
| | - Ulrich Z Hammes
- Plant Systems Biology, School of Life Sciences Weihenstephan, Technical University of Munich, 85354 Freising, Germany
| | - Mechthild Tegeder
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
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4
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Kong SG, Yamazaki Y, Shimada A, Kijima ST, Hirose K, Katoh K, Ahn J, Song HG, Han JW, Higa T, Takano A, Nakamura Y, Suetsugu N, Kohda D, Uyeda TQP, Wada M. CHLOROPLAST UNUSUAL POSITIONING 1 is a plant-specific actin polymerization factor regulating chloroplast movement. THE PLANT CELL 2024; 36:1159-1181. [PMID: 38134410 PMCID: PMC10980345 DOI: 10.1093/plcell/koad320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 11/09/2023] [Accepted: 12/18/2023] [Indexed: 12/24/2023]
Abstract
Plants have unique responses to fluctuating light conditions. One such response involves chloroplast photorelocation movement, which optimizes photosynthesis under weak light by the accumulation of chloroplasts along the periclinal side of the cell, which prevents photodamage under strong light by avoiding chloroplast positioning toward the anticlinal side of the cell. This light-responsive chloroplast movement relies on the reorganization of chloroplast actin (cp-actin) filaments. Previous studies have suggested that CHLOROPLAST UNUSUAL POSITIONING 1 (CHUP1) is essential for chloroplast photorelocation movement as a regulator of cp-actin filaments. In this study, we conducted comprehensive analyses to understand CHUP1 function. Functional, fluorescently tagged CHUP1 colocalized with and was coordinately reorganized with cp-actin filaments on the chloroplast outer envelope during chloroplast movement in Arabidopsis thaliana. CHUP1 distribution was reversibly regulated in a blue light- and phototropin-dependent manner. X-ray crystallography revealed that the CHUP1-C-terminal domain shares structural homology with the formin homology 2 (FH2) domain, despite lacking sequence similarity. Furthermore, the CHUP1-C-terminal domain promoted actin polymerization in the presence of profilin in vitro. Taken together, our findings indicate that CHUP1 is a plant-specific actin polymerization factor that has convergently evolved to assemble cp-actin filaments and enables chloroplast photorelocation movement.
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Affiliation(s)
- Sam-Geun Kong
- Department of Biological Sciences, College of Natural Sciences, Kongju National University, Chungnam 32588, Korea
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan
| | - Yosuke Yamazaki
- Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo 169-8555, Japan
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Atsushi Shimada
- Division of Structural Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Saku T Kijima
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8562, Japan
| | - Keiko Hirose
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8562, Japan
| | - Kaoru Katoh
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8562, Japan
| | - Jeongsu Ahn
- Department of Biological Sciences, College of Natural Sciences, Kongju National University, Chungnam 32588, Korea
| | - Hyun-Geun Song
- Department of Biological Sciences, College of Natural Sciences, Kongju National University, Chungnam 32588, Korea
| | - Jae-Woo Han
- Department of Biological Sciences, College of Natural Sciences, Kongju National University, Chungnam 32588, Korea
| | - Takeshi Higa
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Akira Takano
- Division of Structural Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Yuki Nakamura
- Division of Structural Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Noriyuki Suetsugu
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan
| | - Daisuke Kohda
- Division of Structural Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Taro Q P Uyeda
- Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo 169-8555, Japan
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8562, Japan
| | - Masamitsu Wada
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan
- Graduate School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan
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5
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Schwenkert S, Lo WT, Szulc B, Yip CK, Pratt AI, Cusack SA, Brandt B, Leister D, Kunz HH. Probing the physiological role of the plastid outer-envelope membrane using the oemiR plasmid collection. G3 (BETHESDA, MD.) 2023; 13:jkad187. [PMID: 37572358 PMCID: PMC10542568 DOI: 10.1093/g3journal/jkad187] [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: 07/20/2023] [Revised: 07/20/2023] [Accepted: 08/04/2023] [Indexed: 08/14/2023]
Abstract
Plastids are the site of complex biochemical pathways, most prominently photosynthesis. The organelle evolved through endosymbiosis with a cyanobacterium, which is exemplified by the outer envelope membrane that harbors more than 40 proteins in Arabidopsis. Their evolutionary conservation indicates high significance for plant cell function. While a few proteins are well-studied as part of the protein translocon complex the majority of outer envelope protein functions is unclear. Gaining a deeper functional understanding has been complicated by the lack of observable loss-of-function mutant phenotypes, which is often rooted in functional genetic redundancy. Therefore, we designed outer envelope-specific artificial micro RNAs (oemiRs) capable of downregulating transcripts from several loci simultaneously. We successfully tested oemiR function by performing a proof-of-concept screen for pale and cold-sensitive mutants. An in-depth analysis of pale mutant alleles deficient in the translocon component TOC75 using proteomics provided new insights into putative compensatory import pathways. The cold stress screen not only recapitulated 3 previously known phenotypes of cold-sensitive mutants but also identified 4 mutants of additional oemiR outer envelope loci. Altogether our study revealed a role of the outer envelope to tolerate cold conditions and showcasts the power of the oemiR collection to research the significance of outer envelope proteins.
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Affiliation(s)
- Serena Schwenkert
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität Munich, 82152 Planegg-Martinsried, Germany
| | - Wing Tung Lo
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität Munich, 82152 Planegg-Martinsried, Germany
| | - Beata Szulc
- Plant Biochemistry, Faculty of Biology, Ludwig-Maximilians-Universität Munich, 82152 Planegg-Martinsried, Germany
| | - Chun Kwan Yip
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität Munich, 82152 Planegg-Martinsried, Germany
| | - Anna I Pratt
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA 99164-4236, USA
| | | | - Benjamin Brandt
- Plant Biochemistry, Faculty of Biology, Ludwig-Maximilians-Universität Munich, 82152 Planegg-Martinsried, Germany
| | - Dario Leister
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität Munich, 82152 Planegg-Martinsried, Germany
| | - Hans-Henning Kunz
- Plant Biochemistry, Faculty of Biology, Ludwig-Maximilians-Universität Munich, 82152 Planegg-Martinsried, Germany
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA 99164-4236, USA
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6
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Won SY, Soundararajan P, Irulappan V, Kim JS. In-silico, evolutionary, and functional analysis of CHUP1 and its related proteins in Bienertia sinuspersici-a comparative study across C 3, C 4, CAM, and SCC 4 model plants. PeerJ 2023; 11:e15696. [PMID: 37456874 PMCID: PMC10348308 DOI: 10.7717/peerj.15696] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 06/14/2023] [Indexed: 07/18/2023] Open
Abstract
Single-cell C4 (SCC4) plants with bienertioid anatomy carry out photosynthesis in a single cell. Chloroplast movement is the underlying phenomenon, where chloroplast unusual positioning 1 (CHUP1) plays a key role. This study aimed to characterize CHUP1 and CHUP1-like proteins in an SCC4 photosynthetic plant, Bienertia sinuspersici. Also, a comparative analysis of SCC4 CHUP1 was made with C3, C4, and CAM model plants including an extant basal angiosperm, Amborella. The CHUP1 gene exists as a single copy from the basal angiosperms to SCC4 plants. Our analysis identified that Chenopodium quinoa, a recently duplicated allotetraploid, has two copies of CHUP1. In addition, the numbers of CHUP1-like and its associated proteins such as CHUP1-like_a, CHUP1-like_b, HPR, TPR, and ABP varied between the species. Hidden Markov Model analysis showed that the gene size of CHUP1-like_a and CHUP1-like_b of SCC4 species, Bienertia, and Suaeda were enlarged than other plants. Also, we identified that CHUP1-like_a and CHUP1-like_b are absent in Arabidopsis and Amborella, respectively. Motif analysis identified several conserved and variable motifs based on the orders (monocot and dicot) as well as photosynthetic pathways. For instance, CAM plants such as pineapple and cactus shared certain motifs of CHUP1-like_a irrespective of their distant phylogenetic relationship. The free ratio model showed that CHUP1 maintained purifying selection, whereas CHUP1-like_a and CHUP1-like_b have adaptive functions between SCC4 plants and quinoa. Similarly, rice and maize branches displayed functional diversification on CHUP1-like_b. Relative gene expression data showed that during the subcellular compartmentalization process of Bienertia, CHUP1 and actin-binding proteins (ABP) genes showed a similar pattern of expression. Altogether, the results of this study provide insight into the evolutionary and functional details of CHUP1 and its associated proteins in the development of the SCC4 system in comparison with other C3, C4, and CAM model plants.
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Affiliation(s)
- So Youn Won
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju-si, Jeollabuk-do, South Korea
| | - Prabhakaran Soundararajan
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju-si, Jeollabuk-do, South Korea
| | - Vadivelmurugan Irulappan
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju-si, Jeollabuk-do, South Korea
| | - Jung Sun Kim
- Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju-si, Jeollabuk-do, South Korea
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7
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Songster LD, Bhuyan D, Christensen JR, Reck-Peterson SL. Woronin body hitchhiking on early endosomes is dispensable for septal localization in Aspergillus nidulans. Mol Biol Cell 2023; 34:br9. [PMID: 37017489 PMCID: PMC10295486 DOI: 10.1091/mbc.e23-01-0025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/28/2023] [Accepted: 03/28/2023] [Indexed: 04/06/2023] Open
Abstract
The proper functioning of organelles depends on their intracellular localization, mediated by motor protein-dependent transport on cytoskeletal tracks. Rather than directly associating with a motor protein, peroxisomes move by hitchhiking on motile early endosomes in the filamentous fungus Aspergillus nidulans. However, the physiological role of peroxisome hitchhiking is unclear. Peroxisome hitchhiking requires the protein PxdA, which is conserved within the fungal subphylum Pezizomycotina but absent from other fungal clades. Woronin bodies are specialized peroxisomes that are also unique to the Pezizomycotina. In these fungi, multinucleate hyphal segments are separated by incomplete cell walls called septa that possess a central pore enabling cytoplasmic exchange. Upon damage to a hyphal segment, Woronin bodies plug septal pores to prevent widespread leakage. Here, we tested whether peroxisome hitchhiking is important for Woronin body motility, distribution, and function in A. nidulans. We show that Woronin body proteins are present within all motile peroxisomes and hitchhike on PxdA-labeled early endosomes during bidirectional, long-distance movements. Loss of peroxisome hitchhiking significantly affected Woronin body distribution and motility in the cytoplasm, but Woronin body hitchhiking is ultimately dispensable for septal localization and plugging.
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Affiliation(s)
- Livia D. Songster
- Department of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093
| | - Devahuti Bhuyan
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Jenna R. Christensen
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Samara L. Reck-Peterson
- Department of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
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8
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Yong LK, Kodama Y. Dark-induced chloroplast relocation depends on actin filaments in the liverwort Apopellia endiviifolia along with the light- and cold-induced relocations. PLANT, CELL & ENVIRONMENT 2023; 46:1822-1832. [PMID: 36782387 DOI: 10.1111/pce.14566] [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: 12/12/2022] [Revised: 02/03/2023] [Accepted: 02/12/2023] [Indexed: 05/04/2023]
Abstract
Chloroplasts move to the periclinal walls of cells under weak light to harness light energy for photosynthesis and to anticlinal walls to avoid strong light. These responses involve the cytoskeleton components microtubules and/or actin filaments. In the dark, chloroplasts move to the anticlinal cell walls bordering neighbouring cells (dark-positioning response), but this response in various plants normally requires a prolonged dark incubation period, which has hampered analysis. However, we recently demonstrated the dark-positioning response that can be induced after a short period of dark incubation in the liverwort Apopellia endiviifolia. Here, we investigated whether the cytoskeleton components function in the dark-positioning response of A. endiviifolia cells. Microtubules and actin filaments were fluorescently visualised in A. endiviifolia cells and were disrupted following treatment with the microtubule and actin filament polymerisation inhibitors. The dark-positioning response was unaffected in the cells with disrupted microtubules. By contrast, the dark-positioning response was inhibited by the disruption of actin filaments. The disruption of actin filaments also restricted chloroplast mobility during light- and cold-dependent chloroplast movements in A. endiviifolia. Therefore, the dark-positioning response of A. endiviifolia depends solely on an actin filament-associated motility mechanism, as do the light- and cold-dependent chloroplast responses.
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Affiliation(s)
- Lee-Kien Yong
- Center for Bioscience Research and Education, Utsunomiya University, Tochigi, Japan
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Yutaka Kodama
- Center for Bioscience Research and Education, Utsunomiya University, Tochigi, Japan
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
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Yuan N, Mendu L, Ghose K, Witte CS, Frugoli J, Mendu V. FKF1 Interacts with CHUP1 and Regulates Chloroplast Movement in Arabidopsis. PLANTS (BASEL, SWITZERLAND) 2023; 12:542. [PMID: 36771626 PMCID: PMC9920714 DOI: 10.3390/plants12030542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/22/2023] [Accepted: 01/23/2023] [Indexed: 06/18/2023]
Abstract
Plants have mechanisms to relocate chloroplasts based on light intensities in order to maximize photosynthesis and reduce photodamage. Under low light, chloroplasts move to the periclinal walls to increase photosynthesis (accumulation) and move to the anticlinal walls under high light to avoid photodamage, and even cell death (avoidance). Arabidopsis blue light receptors phot1 and phot2 (phototropins) have been reported to regulate chloroplast movement. This study discovered that another blue light receptor, FLAVIN-BINDING KELCH REPEAT F-BOX1 (FKF1), regulates chloroplast photorelocation by physically interacting with chloroplast unusual positioning protein 1 (CHUP1), a critical component of the chloroplast motility system. Leaf cross-sectioning and red-light transmittance results showed that overexpression of FKF1 compromised the avoidance response, while the absence of FKF1 enhanced chloroplast movements under high light. Western blot analysis showed that CHUP1 protein abundance is altered in FKF1 mutants and overexpression lines, indicating a potential regulation of CHUP1 by FKF1. qPCR results showed that two photorelocation pathway genes, JAC1 and THRUMIN1, were upregulated in FKF1-OE lines, and overexpression of FKF1 in the THRUMIN1 mutant weakened its accumulation and avoidance responses, indicating that JAC1 and THRUMIN1 may play a role in the FKF1-mediated chloroplast avoidance response. However, the precise functional roles of JAC1 and THRUMIN1 in this process are not known.
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Affiliation(s)
- Ning Yuan
- Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, USA
| | - Lavanya Mendu
- Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, USA
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717, USA
| | - Kaushik Ghose
- Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, USA
| | - Carlie Shea Witte
- Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, USA
| | - Julia Frugoli
- Department of Genetics & Biochemistry, Clemson University, Clemson, SC 29634, USA
| | - Venugopal Mendu
- Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, USA
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717, USA
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10
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Songster LD, Bhuyan D, Christensen JR, Reck-Peterson SL. Woronin bodies move dynamically and bidirectionally by hitchhiking on early endosomes in Aspergillus nidulans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.20.524968. [PMID: 36711994 PMCID: PMC9882315 DOI: 10.1101/2023.01.20.524968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The proper functioning of organelles depends on their intracellular localization, mediated by motor protein-dependent transport on cytoskeletal tracks. Rather than directly associating with a motor protein, peroxisomes move by hitchhiking on motile early endosomes in the filamentous fungus Aspergillus nidulans . However, the cellular function of peroxisome hitchhiking is unclear. Peroxisome hitchhiking requires the protein PxdA, which is conserved within the fungal subphylum Pezizomycotina, but absent from other fungal clades. Woronin bodies are specialized peroxisomes that are also unique to the Pezizomycotina. In these fungi, multinucleate hyphal segments are separated by incomplete cell walls called septa that possess a central pore enabling cytoplasmic exchange. Upon damage to a hyphal segment, Woronin bodies plug septal pores to prevent wide-spread leakage. Here, we tested if peroxisome hitchhiking is important for Woronin body motility, distribution, and function in A. nidulans . We show that Woronin body proteins are present within all motile peroxisomes and hitchhike on PxdA-labeled early endosomes during bidirectional, long-distance movements. Loss of peroxisome hitchhiking by knocking out pxdA significantly affected Woronin body distribution and motility in the cytoplasm, but Woronin body hitchhiking is ultimately dispensable for septal localization and plugging.
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Affiliation(s)
- Livia D. Songster
- Department of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA
| | - Devahuti Bhuyan
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Jenna R. Christensen
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA,Correspondence should be addressed to JRC () or SLR-P ()
| | - Samara L. Reck-Peterson
- Department of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA,Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA,Howard Hughes Medical Institute, Chevy Chase, MD, USA,Correspondence should be addressed to JRC () or SLR-P ()
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11
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Chloroplasts in plant cells show active glassy behavior under low-light conditions. Proc Natl Acad Sci U S A 2023; 120:e2216497120. [PMID: 36638210 PMCID: PMC9934296 DOI: 10.1073/pnas.2216497120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Plants have developed intricate mechanisms to adapt to changing light conditions. Besides phototropism and heliotropism (differential growth toward light and diurnal motion with respect to sunlight, respectively), chloroplast motion acts as a fast mechanism to change the intracellular structure of leaf cells. While chloroplasts move toward the sides of the plant cell to avoid strong light, they accumulate and spread out into a layer on the bottom of the cell at low light to increase the light absorption efficiency. Although the motion of chloroplasts has been studied for over a century, the collective organelle motion leading to light-adapting self-organized structures remains elusive. Here, we study the active motion of chloroplasts under dim-light conditions, leading to an accumulation in a densely packed quasi-2D layer. We observe burst-like rearrangements and show that these dynamics resemble systems close to the glass transition by tracking individual chloroplasts. Furthermore, we provide a minimal mathematical model to uncover relevant system parameters controlling the stability of the dense configuration of chloroplasts. Our study suggests that the meta-stable caging close to the glass transition in the chloroplast monolayer serves a physiological relevance: Chloroplasts remain in a spread-out configuration to increase the light uptake but can easily fluidize when the activity is increased to efficiently rearrange the structure toward an avoidance state. Our research opens questions about the role that dynamical phase transitions could play in self-organized intracellular responses of plant cells toward environmental cues.
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12
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Xin GY, Li LP, Wang PT, Li XY, Han YJ, Zhao X. The action of enhancing weak light capture via phototropic growth and chloroplast movement in plants. STRESS BIOLOGY 2022; 2:50. [PMID: 37676522 PMCID: PMC10441985 DOI: 10.1007/s44154-022-00066-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 10/11/2022] [Indexed: 09/08/2023]
Abstract
To cope with fluctuating light conditions, terrestrial plants have evolved precise regulation mechanisms to help optimize light capture and increase photosynthetic efficiency. Upon blue light-triggered autophosphorylation, activated phototropin (PHOT1 and PHOT2) photoreceptors function solely or redundantly to regulate diverse responses, including phototropism, chloroplast movement, stomatal opening, and leaf positioning and flattening in plants. These responses enhance light capture under low-light conditions and avoid photodamage under high-light conditions. NON-PHOTOTROPIC HYPOCOTYL 3 (NPH3) and ROOT PHOTOTROPISM 2 (RPT2) are signal transducers that function in the PHOT1- and PHOT2-mediated response. NPH3 is required for phototropism, leaf expansion and positioning. RPT2 regulates chloroplast accumulation as well as NPH3-mediated responses. NRL PROTEIN FOR CHLOROPLAST MOVEMENT 1 (NCH1) was recently identified as a PHOT1-interacting protein that functions redundantly with RPT2 to mediate chloroplast accumulation. The PHYTOCHROME KINASE SUBSTRATE (PKS) proteins (PKS1, PKS2, and PKS4) interact with PHOT1 and NPH3 and mediate hypocotyl phototropic bending. This review summarizes advances in phototropic growth and chloroplast movement induced by light. We also focus on how crosstalk in signaling between phototropism and chloroplast movement enhances weak light capture, providing a basis for future studies aiming to delineate the mechanism of light-trapping plants to improve light-use efficiency.
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Affiliation(s)
- Guang-Yuan Xin
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Lu-Ping Li
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Peng-Tao Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Xin-Yue Li
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Yuan-Ji Han
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Xiang Zhao
- 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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Sun Y, Yao Z, Ye Y, Fang J, Chen H, Lyu Y, Broad W, Fournier M, Chen G, Hu Y, Mohammed S, Ling Q, Jarvis RP. Ubiquitin-based pathway acts inside chloroplasts to regulate photosynthesis. SCIENCE ADVANCES 2022; 8:eabq7352. [PMID: 36383657 PMCID: PMC9668298 DOI: 10.1126/sciadv.abq7352] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Photosynthesis is the energetic basis for most life on Earth, and in plants it operates inside double membrane-bound organelles called chloroplasts. The photosynthetic apparatus comprises numerous proteins encoded by the nuclear and organellar genomes. Maintenance of this apparatus requires the action of internal chloroplast proteases, but a role for the nucleocytosolic ubiquitin-proteasome system (UPS) was not expected, owing to the barrier presented by the double-membrane envelope. Here, we show that photosynthesis proteins (including those encoded internally by chloroplast genes) are ubiquitinated and processed via the CHLORAD pathway: They are degraded by the 26S proteasome following CDC48-dependent retrotranslocation to the cytosol. This demonstrates that the reach of the UPS extends to the interior of endosymbiotically derived chloroplasts, where it acts to regulate photosynthesis, arguably the most fundamental process of life.
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Affiliation(s)
- Yi Sun
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
| | - Zujie Yao
- National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yiting Ye
- National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jun Fang
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
| | - Honglin Chen
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Yuping Lyu
- National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
- Shanghai Chenshan Plant Science Research Center, Chinese Academy of Sciences, Shanghai, China
| | - William Broad
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
| | - Marjorie Fournier
- Advanced Proteomics Facility, University of Oxford, Oxford OX1 3QU, UK
| | - Genyun Chen
- National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yonghong Hu
- Shanghai Chenshan Plant Science Research Center, Chinese Academy of Sciences, Shanghai, China
| | - Shabaz Mohammed
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
- Rosalind Franklin Institute, Oxfordshire OX11 0FA, UK
| | - Qihua Ling
- National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- CAS-JIC Center of Excellence for Plant and Microbial Sciences (CEPAMS), Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- Corresponding author. (Q.L.); (R.P.J.)
| | - R. Paul Jarvis
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
- Corresponding author. (Q.L.); (R.P.J.)
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14
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Christensen JR, Reck-Peterson SL. Hitchhiking Across Kingdoms: Cotransport of Cargos in Fungal, Animal, and Plant Cells. Annu Rev Cell Dev Biol 2022; 38:155-178. [PMID: 35905769 PMCID: PMC10967659 DOI: 10.1146/annurev-cellbio-120420-104341] [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: 11/09/2022]
Abstract
Eukaryotic cells across the tree of life organize their subcellular components via intracellular transport mechanisms. In canonical transport, myosin, kinesin, and dynein motor proteins interact with cargos via adaptor proteins and move along filamentous actin or microtubule tracks. In contrast to this canonical mode, hitchhiking is a newly discovered mode of intracellular transport in which a cargo attaches itself to an already-motile cargo rather than directly associating with a motor protein itself. Many cargos including messenger RNAs, protein complexes, and organelles hitchhike on membrane-bound cargos. Hitchhiking-like behaviors have been shown to impact cellular processes including local protein translation, long-distance signaling, and organelle network reorganization. Here, we review instances of cargo hitchhiking in fungal, animal, and plant cells and discuss the potential cellular and evolutionary importance of hitchhiking in these different contexts.
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Affiliation(s)
- Jenna R Christensen
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA; ,
| | - Samara L Reck-Peterson
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA; ,
- Department of Biological Sciences, Cell and Developmental Biology Section, University of California, San Diego, La Jolla, California, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
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15
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Dwyer ME, Hangarter RP. Light-induced displacement of PLASTID MOVEMENT IMPAIRED1 precedes light-dependent chloroplast movements. PLANT PHYSIOLOGY 2022; 189:1866-1880. [PMID: 35477788 PMCID: PMC9237684 DOI: 10.1093/plphys/kiac193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
Light-dependent chloroplast movements are an actin-dependent cellular response to changes in the light environment that help plants maximize photosynthetic potential and reduce photodamage. Over a dozen proteins are known to be required for normal chloroplast movements, but the molecular mechanisms regulating the transformation of light perception into chloroplast motility are not fully understood. Here, we show that in Arabidopsis (Arabidopsis thaliana) the actin-bundling plasma membrane-associated proteins THRUMIN1, PLASTID MOVEMENT IMPAIRED1 (PMI1), and KINESIN-LIKE PROTEIN FOR ACTIN-BASED CHLOROPLAST MOVEMENT1 (KAC1) interact through the 14-3-3 proteins KAPPA and OMEGA. We also show that the interaction of PMI1 with 14-3-3 KAPPA and OMEGA is regulated by blue light activation of the Phototropin2 photoreceptor. Live-cell confocal microscopy revealed light-induced dynamic changes in the cellular localizations of PMI1 and KAC1. In particular, PMI1 was relocated away from irradiated areas of the plasma membrane in less than a minute after blue light exposure, consistent with PMI1 playing a critical role in initiating light-dependent chloroplast movements. We present a modified conceptual model for high light-dependent chloroplast movements in which PMI1 acts as the mobile signal that initiates a coordinated sequence of changes in protein-protein and protein-plasma membrane interactions that initiate the chloroplast movement response and determine where in the cell chloroplasts are able to anchor to the plasma membrane.
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Affiliation(s)
- Matthew E Dwyer
- Department of Biology, Indiana University, Bloomington, Indiana, 47405, USA
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16
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Emerging Roles of Motile Epidermal Chloroplasts in Plant Immunity. Int J Mol Sci 2022; 23:ijms23074043. [PMID: 35409402 PMCID: PMC8999904 DOI: 10.3390/ijms23074043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/02/2022] [Accepted: 04/05/2022] [Indexed: 11/21/2022] Open
Abstract
Plant epidermis contains atypical small chloroplasts. However, the physiological role of this organelle is unclear compared to that of large mesophyll chloroplasts, the well-known function of which is photosynthesis. Although knowledge of the involvement of chloroplasts in the plant immunity has been expanded to date, the differences between the epidermal and mesophyll chloroplasts are beyond the scope of this study. Given the role of the plant epidermis as a barrier to environmental stresses, including pathogen attacks, and the immune-related function of chloroplasts, plant defense research on epidermal chloroplasts is an emerging field. Recent studies have revealed the dynamic movements of epidermal chloroplasts in response to fungal and oomycete pathogens. Furthermore, epidermal chloroplast-associated proteins and cellular events that are tightly linked to epidermal resistance against pathogens have been reported. In this review, I have focused on the recent progress in epidermal chloroplast-mediated plant immunity.
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17
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Breeze E, Mullineaux PM. The Passage of H 2O 2 from Chloroplasts to Their Associated Nucleus during Retrograde Signalling: Reflections on the Role of the Nuclear Envelope. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11040552. [PMID: 35214888 PMCID: PMC8876790 DOI: 10.3390/plants11040552] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/11/2022] [Accepted: 02/15/2022] [Indexed: 05/05/2023]
Abstract
The response of chloroplasts to adverse environmental cues, principally increases in light intensity, stimulates chloroplast-to-nucleus retrograde signalling, which leads to the induction of immediate protective responses and longer-term acclimation. Hydrogen peroxide (H2O2), generated during photosynthesis, is proposed to both initiate and transduce a retrograde signal in response to photoinhibitory light intensities. Signalling specificity achieved by chloroplast-sourced H2O2 for signal transduction may be dependent upon the oft-observed close association of a proportion of these organelles with the nucleus. In this review, we consider more precisely the nature of the close association between a chloroplast appressed to the nucleus and the requirement for H2O2 to cross both the double membranes of the chloroplast and nuclear envelopes. Of particular relevance is that the endoplasmic reticulum (ER) has close physical contact with chloroplasts and is contiguous with the nuclear envelope. Therefore, the perinuclear space, which transducing H2O2 molecules would have to cross, may have an oxidising environment the same as the ER lumen. Based on studies in animal cells, the ER lumen may be a significant source of H2O2 in plant cells arising from the oxidative folding of proteins. If this is the case, then there is potential for the ER lumen/perinuclear space to be an important location to modify chloroplast-to-nucleus H2O2 signal transduction and thereby introduce modulation of it by additional different environmental cues. These would include for example, heat stress and pathogen infection, which induce the unfolded protein response characterised by an increased H2O2 level in the ER lumen.
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Affiliation(s)
- Emily Breeze
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK;
| | - Philip M. Mullineaux
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK
- Correspondence: ; Tel.: +44-1206-872118
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18
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Deniset-Besseau A, Coat R, Moutel B, Rebois R, Mathurin J, Grizeau D, Dazzi A, Gonçalves O. Revealing Lipid Body Formation and its Subcellular Reorganization in Oleaginous Microalgae Using Correlative Optical Microscopy and Infrared Nanospectroscopy. APPLIED SPECTROSCOPY 2021; 75:1538-1547. [PMID: 34608808 DOI: 10.1177/00037028211050659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The purpose of this work is to develop an integrated imaging approach to characterize without labeling at the sub-cellular level the formation of lipid body droplets (LBs) in microalgae undergoing nitrogen starvation. First conventional optical microscopy approaches, gas chromatography, and turbidimetry measurements allowed to monitor the biomass and the total lipid content in the oleaginous microalgae Parachlorella kesslerii during the starvation process. Then a local analysis of the LBs was proposed using an innovative infrared nanospectroscopy technique called atomic force microscopy-based infrared spectroscopy (AFM-IR). This label-free technique assessed the formation of LBs and allowed to look into the LB composition thanks to the acquisition of local infrared spectra. Last correlative measurements using fluorescence microscopy and AFM-IR were performed to investigate the subcellular reorganization of LB and the chloroplasts.
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Affiliation(s)
| | - Rémy Coat
- LUNAM Université, Université de Nantes, GEPEA, UMR CNRS-6144, Saint-Nazaire Cedex, France
| | - Benjamin Moutel
- LUNAM Université, Université de Nantes, GEPEA, UMR CNRS-6144, Saint-Nazaire Cedex, France
| | - Rolando Rebois
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR 8000, Orsay, France
| | - Jérémie Mathurin
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR 8000, Orsay, France
| | - Dominique Grizeau
- LUNAM Université, Université de Nantes, GEPEA, UMR CNRS-6144, Saint-Nazaire Cedex, France
| | - Alexandre Dazzi
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR 8000, Orsay, France
| | - Olivier Gonçalves
- LUNAM Université, Université de Nantes, GEPEA, UMR CNRS-6144, Saint-Nazaire Cedex, France
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19
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Dwyer ME, Hangarter RP. Light-dependent phosphorylation of THRUMIN1 regulates its association with actin filaments and 14-3-3 proteins. PLANT PHYSIOLOGY 2021; 187:1445-1461. [PMID: 34618069 PMCID: PMC8566215 DOI: 10.1093/plphys/kiab374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 07/12/2021] [Indexed: 06/13/2023]
Abstract
Light-dependent chloroplast movements in leaf cells contribute to the optimization of photosynthesis. Low-light conditions induce chloroplast accumulation along periclinal cell surfaces, providing greater access to available light, whereas high light induces movement of chloroplasts to anticlinal cell surfaces, providing photodamage protection and allowing more light to reach underlying cell layers. The THRUMIN1 protein is required for normal chloroplast movements in Arabidopsis (Arabidopsis thaliana) and has been shown to localize at the plasma membrane and to undergo rapid light-dependent interactions with actin filaments through the N-terminal intrinsically disordered region (IDR). A predicted WASP-Homology 2 domain was found in the IDR but mutations in this domain did not disrupt localization of THRUMIN1:YFP to actin filaments. A series of other protein truncations and site-directed mutations of known and putative phosphorylation sites indicated that a phosphomimetic mutation (serine to aspartic acid) at position 170 disrupted localization of THRUMIN1 to actin filaments. However, the phosphomimetic mutant rescued the thrumin1-2 mutant phenotype for chloroplast movement and raises questions about the role of THRUMIN1's interaction with actin. Mutation of serine 146 to aspartic acid also resulted in cytoplasmic localization of THRUMIN1:YFP in Nicotiana benthamiana. Mutations to a group of putative zinc-binding cysteine clusters implicate the C-terminus of THRUMIN1 in chloroplast movement. Phosphorylation-dependent association of THRUMIN1 with 14-3-3 KAPPA and OMEGA were also identified. Together, these studies provide insights into the mechanistic role of THRUMIN1 in light-dependent chloroplast movements.
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Affiliation(s)
- Matthew E Dwyer
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
| | - Roger P Hangarter
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
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20
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Wang J, Liang YP, Zhu JD, Wang YX, Yang MY, Yan HR, Lv QY, Cheng K, Zhao X, Zhang X. Phototropin 1 Mediates High-Intensity Blue Light-Induced Chloroplast Accumulation Response in a Root Phototropism 2-Dependent Manner in Arabidopsis phot2 Mutant Plants. FRONTIERS IN PLANT SCIENCE 2021; 12:704618. [PMID: 34646282 PMCID: PMC8502927 DOI: 10.3389/fpls.2021.704618] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 08/27/2021] [Indexed: 06/13/2023]
Abstract
Phototropins, namely, phototropin 1 (phot1) and phototropin 2 (phot2), mediate chloroplast movement to maximize photosynthetic efficiency and prevent photodamage in plants. Phot1 primarily functions in chloroplast accumulation process, whereas phot2 mediates both chloroplast avoidance and accumulation responses. The avoidance response of phot2-mediated chloroplasts under high-intensity blue light (HBL) limited the understanding of the function of phot1 in the chloroplast accumulation process at the HBL condition. In this study, we showed that the phot2 mutant exhibits a chloroplast accumulation response under HBL, which is defective when the root phototropism 2 (RPT2) gene is mutated in the phot2 background, mimicking the phenotype of the phot1 phot2 double mutant. A further analysis revealed that the expression of RPT2 was induced by HBL and the overexpression of RPT2 could partially enhance the chloroplast accumulation response under HBL. These results confirmed that RPT2 also participates in regulating the phot1-mediated chloroplast accumulation response under HBL. In contrast, RPT2 functions redundantly with neural retina leucine zipper (NRL) protein for chloroplast movement 1 (NCH1) under low-light irradiation. In addition, no chloroplast accumulation response was detected in the phot2 jac1 double mutant under HBL, which has been previously observed in phot2 rpt2 and phot1 phot2 double mutants. Taken together, our results indicated that phot1 mediates the HBL-induced chloroplast accumulation response in an RPT2-dependent manner and is also regulated by j-domain protein required for chloroplast accumulation response 1 (JAC1).
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21
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Jamsheer K M, Kumar M, Srivastava V. SNF1-related protein kinase 1: the many-faced signaling hub regulating developmental plasticity in plants. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:6042-6065. [PMID: 33693699 DOI: 10.1093/jxb/erab079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 02/17/2021] [Indexed: 05/03/2023]
Abstract
The Snf1-related protein kinase 1 (SnRK1) is the plant homolog of the heterotrimeric AMP-activated protein kinase/sucrose non-fermenting 1 (AMPK/Snf1), which works as a major regulator of growth under nutrient-limiting conditions in eukaryotes. Along with its conserved role as a master regulator of sugar starvation responses, SnRK1 is involved in controlling the developmental plasticity and resilience under diverse environmental conditions in plants. In this review, through mining and analyzing the interactome and phosphoproteome data of SnRK1, we are highlighting its role in fundamental cellular processes such as gene regulation, protein synthesis, primary metabolism, protein trafficking, nutrient homeostasis, and autophagy. Along with the well-characterized molecular interaction in SnRK1 signaling, our analysis highlights several unchartered regions of SnRK1 signaling in plants such as its possible communication with chromatin remodelers, histone modifiers, and inositol phosphate signaling. We also discuss potential reciprocal interactions of SnRK1 signaling with other signaling pathways and cellular processes, which could be involved in maintaining flexibility and homeostasis under different environmental conditions. Overall, this review provides a comprehensive overview of the SnRK1 signaling network in plants and suggests many novel directions for future research.
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Affiliation(s)
- Muhammed Jamsheer K
- Amity Food & Agriculture Foundation, Amity University Uttar Pradesh, Sector 125, Noida 201313, India
| | - Manoj Kumar
- Amity Food & Agriculture Foundation, Amity University Uttar Pradesh, Sector 125, Noida 201313, India
| | - Vibha Srivastava
- Department of Crop, Soil & Environmental Sciences, University of Arkansas, Fayetteville, AR, USA
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22
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Irieda H, Takano Y. Epidermal chloroplasts are defense-related motile organelles equipped with plant immune components. Nat Commun 2021; 12:2739. [PMID: 34016974 PMCID: PMC8137707 DOI: 10.1038/s41467-021-22977-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 04/06/2021] [Indexed: 12/24/2022] Open
Abstract
In addition to conspicuous large mesophyll chloroplasts, where most photosynthesis occurs, small epidermal chloroplasts have also been observed in plant leaves. However, the functional significance of this small organelle remains unclear. Here, we present evidence that Arabidopsis epidermal chloroplasts control the entry of fungal pathogens. In entry trials, specialized fungal cells called appressoria triggered dynamic movement of epidermal chloroplasts. This movement is controlled by common regulators of mesophyll chloroplast photorelocation movement, designated as the epidermal chloroplast response (ECR). The ECR occurs when the PEN2 myrosinase-related higher-layer antifungal system becomes ineffective, and blockage of the distinct steps of the ECR commonly decreases preinvasive nonhost resistance against fungi. Furthermore, immune components were preferentially localized to epidermal chloroplasts, contributing to antifungal nonhost resistance in the pen2 background. Our findings reveal that atypical small chloroplasts act as defense-related motile organelles by specifically positioning immune components in the plant epidermis, which is the first site of contact between the plant and pathogens. Thus, this work deepens our understanding of the functions of epidermal chloroplasts. Leaf epidermal cells contain small chloroplasts which likely contribute little to photosynthesis and whose function is unclear. Here the authors show that these chloroplasts move toward the leaf surface in response to invasion trials by non-adapted fungal pathogens and contribute to non-host resistance.
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Affiliation(s)
- Hiroki Irieda
- Academic Assembly, Institute of Agriculture, Shinshu University, Nagano, Japan.
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23
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Soler-Garzón A, Oladzad A, Beaver J, Beebe S, Lee R, Lobaton JD, Macea E, McClean P, Raatz B, Rosas JC, Song Q, Miklas PN. NAC Candidate Gene Marker for bgm-1 and Interaction With QTL for Resistance to Bean Golden Yellow Mosaic Virus in Common Bean. FRONTIERS IN PLANT SCIENCE 2021; 12:628443. [PMID: 33841459 PMCID: PMC8027503 DOI: 10.3389/fpls.2021.628443] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 03/03/2021] [Indexed: 05/16/2023]
Abstract
Genetic resistance is the primary means for control of Bean golden yellow mosaic virus (BGYMV) in common bean (Phaseolus vulgaris L.). Breeding for resistance is difficult because of sporadic and uneven infection across field nurseries. We sought to facilitate breeding for BGYMV resistance by improving marker-assisted selection (MAS) for the recessive bgm-1 gene and identifying and developing MAS for quantitative trait loci (QTL) conditioning resistance. Genetic linkage mapping in two recombinant inbred line populations and genome-wide association study (GWAS) in a large breeding population and two diversity panels revealed a candidate gene for bgm-1 and three QTL BGY4.1, BGY7.1, and BGY8.1 on independent chromosomes. A mutation (5 bp deletion) in a NAC (No Apical Meristem) domain transcriptional regulator superfamily protein gene Phvul.003G027100 on chromosome Pv03 corresponded with the recessive bgm-1 resistance allele. The five bp deletion in exon 2 starting at 20 bp (Pv03: 2,601,582) is expected to cause a stop codon at codon 23 (Pv03: 2,601,625), disrupting further translation of the gene. A T m -shift assay marker named PvNAC1 was developed to track bgm-1. PvNAC1 corresponded with bgm-1 across ∼1,000 lines which trace bgm-1 back to a single landrace "Garrapato" from Mexico. BGY8.1 has no effect on its own but exhibited a major effect when combined with bgm-1. BGY4.1 and BGY7.1 acted additively, and they enhanced the level of resistance when combined with bgm-1. T m -shift assay markers were generated for MAS of the QTL, but their effectiveness requires further validation.
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Affiliation(s)
- Alvaro Soler-Garzón
- Irrigated Agriculture Research and Extension Center, Washington State University, Prosser, WA, United States
| | - Atena Oladzad
- Department of Plant Sciences, North Dakota State University, Fargo, ND, United States
| | - James Beaver
- Department of Agroenvironmental Sciences, University of Puerto Rico, Mayagüez, Puerto Rico
| | - Stephen Beebe
- Bean Program, Agrobiodiversity Area, International Center for Tropical Agriculture (CIAT), Cali, Colombia
| | - Rian Lee
- Department of Plant Sciences, North Dakota State University, Fargo, ND, United States
| | - Juan David Lobaton
- Bean Program, Agrobiodiversity Area, International Center for Tropical Agriculture (CIAT), Cali, Colombia
- School of Environmental and Rural Sciences, University of New England, Armidale, SA, Australia
| | - Eliana Macea
- Bean Program, Agrobiodiversity Area, International Center for Tropical Agriculture (CIAT), Cali, Colombia
| | - Phillip McClean
- Department of Plant Sciences, North Dakota State University, Fargo, ND, United States
| | - Bodo Raatz
- Bean Program, Agrobiodiversity Area, International Center for Tropical Agriculture (CIAT), Cali, Colombia
| | - Juan Carlos Rosas
- Department of Agricultural Engineering, Zamorano University, Zamorano, Honduras
| | - Qijian Song
- Soybean Genomics and Improvement Laboratory, United States Department of Agriculture – Agricultural Research Service (USDA-ARS), Beltsville, MD, United States
| | - Phillip N. Miklas
- Irrigated Agriculture Research and Extension Center, Washington State University, Prosser, WA, United States
- Grain Legume Genetics and Physiology Research Unit, United States Department of Agriculture – Agricultural Research Service (USDA-ARS), Prosser, WA, United States
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Roeber VM, Bajaj I, Rohde M, Schmülling T, Cortleven A. Light acts as a stressor and influences abiotic and biotic stress responses in plants. PLANT, CELL & ENVIRONMENT 2021; 44:645-664. [PMID: 33190307 DOI: 10.1111/pce.13948] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/19/2020] [Accepted: 11/09/2020] [Indexed: 05/18/2023]
Abstract
Light is important for plants as an energy source and a developmental signal, but it can also cause stress to plants and modulates responses to stress. Excess and fluctuating light result in photoinhibition and reactive oxygen species (ROS) accumulation around photosystems II and I, respectively. Ultraviolet light causes photodamage to DNA and a prolongation of the light period initiates the photoperiod stress syndrome. Changes in light quality and quantity, as well as in light duration are also key factors impacting the outcome of diverse abiotic and biotic stresses. Short day or shady environments enhance thermotolerance and increase cold acclimation. Similarly, shade conditions improve drought stress tolerance in plants. Additionally, the light environment affects the plants' responses to biotic intruders, such as pathogens or insect herbivores, often reducing growth-defence trade-offs. Understanding how plants use light information to modulate stress responses will support breeding strategies to enhance crop stress resilience. This review summarizes the effect of light as a stressor and the impact of the light environment on abiotic and biotic stress responses. There is a special focus on the role of the different light receptors and the crosstalk between light signalling and stress response pathways.
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Affiliation(s)
- Venja M Roeber
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Berlin, Germany
| | - Ishita Bajaj
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Berlin, Germany
| | - Mareike Rohde
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Berlin, Germany
| | - Thomas Schmülling
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Berlin, Germany
| | - Anne Cortleven
- Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Berlin, Germany
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25
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Kitashova A, Schneider K, Fürtauer L, Schröder L, Scheibenbogen T, Fürtauer S, Nägele T. Impaired chloroplast positioning affects photosynthetic capacity and regulation of the central carbohydrate metabolism during cold acclimation. PHOTOSYNTHESIS RESEARCH 2021; 147:49-60. [PMID: 33211260 PMCID: PMC7728637 DOI: 10.1007/s11120-020-00795-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 11/06/2020] [Indexed: 05/02/2023]
Abstract
Photosynthesis and carbohydrate metabolism of higher plants need to be tightly regulated to prevent tissue damage during environmental changes. The intracellular position of chloroplasts changes due to a changing light regime. Chloroplast avoidance and accumulation response under high and low light, respectively, are well known phenomena, and deficiency of chloroplast movement has been shown to result in photodamage and reduced biomass accumulation. Yet, effects of chloroplast positioning on underlying metabolic regulation are less well understood. Here, we analysed photosynthesis together with metabolites and enzyme activities of the central carbohydrate metabolism during cold acclimation of the chloroplast unusual positioning 1 (chup1) mutant of Arabidopsis thaliana. We compared cold acclimation under ambient and low light and found that maximum quantum yield of PSII was significantly lower in chup1 than in Col-0 under both conditions. Our findings indicated that net CO2 assimilation in chup1 is rather limited by biochemistry than by photochemistry. Further, cold-induced dynamics of sucrose phosphate synthase differed significantly between both genotypes. Together with a reduced rate of sucrose cycling derived from kinetic model simulations our study provides evidence for a central role of chloroplast positioning for photosynthetic and metabolic acclimation to low temperature.
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Affiliation(s)
- Anastasia Kitashova
- Department Biology I, Plant Evolutionary Cell Biology, LMU München, 82152, Planegg-Martinsried, Germany
| | - Katja Schneider
- Department Biology I, Plant Development, LMU München, 82152, Planegg-Martinsried, Germany
| | - Lisa Fürtauer
- Department Biology I, Plant Evolutionary Cell Biology, LMU München, 82152, Planegg-Martinsried, Germany
| | - Laura Schröder
- Department Biology I, Plant Evolutionary Cell Biology, LMU München, 82152, Planegg-Martinsried, Germany
| | - Tim Scheibenbogen
- Department Biology I, Plant Evolutionary Cell Biology, LMU München, 82152, Planegg-Martinsried, Germany
| | - Siegfried Fürtauer
- Department Biology I, Plant Evolutionary Cell Biology, LMU München, 82152, Planegg-Martinsried, Germany
- Fraunhofer Institute for Process Engineering and Packaging IVV, 85354, Freising, Germany
| | - Thomas Nägele
- Department Biology I, Plant Evolutionary Cell Biology, LMU München, 82152, Planegg-Martinsried, Germany.
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26
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Islam MS, Van Nguyen T, Sakamoto W, Takagi S. Phototropin- and photosynthesis-dependent mitochondrial positioning in Arabidopsis thaliana mesophyll cells. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2020; 62:1352-1371. [PMID: 31961050 DOI: 10.1111/jipb.12910] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 01/07/2020] [Indexed: 06/10/2023]
Abstract
Mitochondria are frequently observed in the vicinity of chloroplasts in photosynthesizing cells, and this association is considered necessary for their metabolic interactions. We previously reported that, in leaf palisade cells of Arabidopsis thaliana, mitochondria exhibit blue-light-dependent redistribution together with chloroplasts, which conduct accumulation and avoidance responses under the control of blue-light receptor phototropins. In this study, precise motility analyses by fluorescent microscopy revealed that the individual mitochondria in palisade cells, labeled with green fluorescent protein, exhibit typical stop-and-go movement. When exposed to blue light, the velocity of moving mitochondria increased in 30 min, whereas after 4 h, the frequency of stoppage of mitochondrial movement markedly increased. Using different mutant plants, we concluded that the presence of both phototropin1 and phototropin2 is necessary for the early acceleration of mitochondrial movement. On the contrary, the late enhancement of stoppage of mitochondrial movement occurs only in the presence of phototropin2 and only when intact photosynthesis takes place. A plasma-membrane ghost assay suggested that the stopped mitochondria are firmly adhered to chloroplasts. These results indicate that the physical interaction between mitochondria and chloroplasts is cooperatively mediated by phototropin2- and photosynthesis-dependent signals. The present study might add novel regulatory mechanism for light-dependent plant organelle interactions.
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Affiliation(s)
- Md Sayeedul Islam
- Department of Biological Sciences, Graduate School of Science, Osaka University, Machikaneyama-cho 1-1, Toyonaka, Osaka, 560-0043, Japan
| | - Toan Van Nguyen
- Department of Biological Sciences, Graduate School of Science, Osaka University, Machikaneyama-cho 1-1, Toyonaka, Osaka, 560-0043, Japan
- Agricultural Genetics Institute, National Key Laboratory for Plant Cell Biotechnology, Pham Van Dong road, Bac Tu Liem district, Ha Noi, Vietnam
| | - Wataru Sakamoto
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, Japan
| | - Shingo Takagi
- Department of Biological Sciences, Graduate School of Science, Osaka University, Machikaneyama-cho 1-1, Toyonaka, Osaka, 560-0043, Japan
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27
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Howard MM, Bae A, Pirani Z, Van N, Königer M. Impairment of chloroplast movement reduces growth and delays reproduction of Arabidopsis thaliana in natural and controlled conditions. AMERICAN JOURNAL OF BOTANY 2020; 107:1309-1318. [PMID: 32965027 DOI: 10.1002/ajb2.1537] [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: 03/16/2020] [Accepted: 06/11/2020] [Indexed: 06/11/2023]
Abstract
PREMISE The importance of chloroplast movement for plant growth in constant, controlled light and of nonphotochemical quenching (NPQ) in variable, natural light are known. Here we concurrently investigated growth and reproduction of several Arabidopsis thaliana mutants to assess the relative importance of photoprotection via chloroplast movement and NPQ. METHODS Plants were grown outdoors (natural conditions) or in a growth chamber with variable light and chilling temperatures (controlled conditions). Phenotypic growth and reproductive variables were determined at set times before maturity in wild-type (WT) and phot1, phot2, phot1phot2 (e.g., impaired chloroplast movement, stomatal conductance, leaf flattening), chup1 (impaired chloroplast movement), and npq1 (reduced NPQ) plants. RESULTS Mutants were most adversely affected in natural conditions, with phot1phot2 and chup1 most severely impacted. These mutants bolted later and produced fewer leaves and siliques, less leaf biomass, and fewer secondary inflorescences than WT. In controlled conditions, leaf traits of these mutants were unaffected, but phot1phot2 bolted later and produced fewer secondary inflorescences and siliques than WT. For most variables, there were significant interactions between growth conditions and plant genotype. Many variables were correlated, but those relationships changed with growth conditions and genotype. CONCLUSIONS Phenotypic variables at the time of the harvest were strongly affected by growth conditions and genotype. In natural conditions, phot1phot2 and chup1 mutants were most adversely affected, demonstrating the importance of chloroplast movement. In controlled conditions, only phot1phot2 was consistently affected, also emphasizing the important, pleiotropic effects of phototropins. In both conditions, NPQ was less important.
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Affiliation(s)
- Mia M Howard
- Department of Biological Sciences, Wellesley College, Wellesley, MA, 02481, USA
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Andrea Bae
- Department of Biological Sciences, Wellesley College, Wellesley, MA, 02481, USA
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Zahra Pirani
- Department of Biological Sciences, Wellesley College, Wellesley, MA, 02481, USA
- Drexel University College of Medicine, Philadelphia, PA, 19129, USA
| | - Nhi Van
- Department of Biological Sciences, Wellesley College, Wellesley, MA, 02481, USA
- Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721, USA
| | - Martina Königer
- Department of Biological Sciences, Wellesley College, Wellesley, MA, 02481, USA
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28
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Wilson S, Ruban AV. Rethinking the Influence of Chloroplast Movements on Non-photochemical Quenching and Photoprotection. PLANT PHYSIOLOGY 2020; 183:1213-1223. [PMID: 32404415 PMCID: PMC7333707 DOI: 10.1104/pp.20.00549] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 05/04/2020] [Indexed: 05/25/2023]
Abstract
Under blue light, plant chloroplasts relocate to different areas of the cell. The photoreceptor phototropin2 (phot2) mediates the chloroplast movement mechanism under excess blue light alongside the chloroplast unusual positioning1 (chup1) protein. Recently, it has been proposed that leaf transmittance changes associated with chloroplast relocation affect measurements of nonphotochemical quenching (NPQ), resulting in kinetic differences due to these movements (termed "qM"). We evaluated these claims using Arabidopsis (Arabidopsis thaliana) knock-out mutants lacking either phot2 or chup1 and analyzed the kinetics of both the onset and recovery of NPQ under equivalent intensities of both red and blue light. We also evaluated the photoprotective ability of chloroplast movements both during the early onset of photoinhibition and under sustained excess light. We monitored photoinhibition using the chlorophyll fluorescence parameter of photochemical quenching in the dark, which measures the redox state of QA within PSII without any of the complications of traditional F v /F m measurements. While there were noticeable differences between the responses under red and blue light, the chloroplast movement mechanism had no effect on the rate or amplitude of NPQ onset or recovery. Therefore, we were unable to replicate the "qM" component and its corresponding influence on the kinetics of NPQ in Arabidopsis grown under "shade" conditions. Furthermore, chloroplast relocation had no effect on the high-light tolerance of these plants. These data cast doubt upon the existence of a chloroplast movement-dependent component of NPQ Therefore, the influence of chloroplast movements on photoprotection should be thoroughly reevaluated.
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Affiliation(s)
- Sam Wilson
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, United Kingdom
| | - Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, United Kingdom
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29
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Mullineaux PM, Exposito-Rodriguez M, Laissue PP, Smirnoff N, Park E. Spatial chloroplast-to-nucleus signalling involving plastid-nuclear complexes and stromules. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190405. [PMID: 32362250 PMCID: PMC7209948 DOI: 10.1098/rstb.2019.0405] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Communication between chloroplasts and the nucleus in response to various environmental cues may be mediated by various small molecules. Signalling specificity could be enhanced if the physical contact between these organelles facilitates direct transfer and prevents interference from other subcellular sources of the same molecules. Plant cells have plastid-nuclear complexes, which provide close physical contact between these organelles. Plastid-nuclear complexes have been proposed to facilitate transfer of photosynthesis-derived H2O2 to the nucleus in high light. Stromules (stroma filled tubular plastid extensions) may provide an additional conduit for transfer of a wider range of signalling molecules, including proteins. However, plastid-nuclear complexes and stromules have been hitherto treated as distinct phenomena. We suggest that plastid-nuclear complexes and stromules work in a coordinated manner so that, according to environmental conditions or developmental state, the two modes of connection contribute to varying extents. We hypothesize that this association is dynamic and that there may be a link between plastid-nuclear complexes and the development of stromules. Furthermore, the changes in contact could alter signalling specificity by allowing an extended or different range of signalling molecules to be delivered to the nucleus. This article is part of the theme issue 'Retrograde signalling from endosymbiotic organelles'.
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Affiliation(s)
- Philip M Mullineaux
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
| | | | | | - Nicholas Smirnoff
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Eunsook Park
- Plant Immunity Research Center, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea.,Department of Molecular Biology, College of Agriculture and Natural Resources, University of Wyoming, Laramie WY 82071, USA
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30
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Ishishita K, Higa T, Tanaka H, Inoue SI, Chung A, Ushijima T, Matsushita T, Kinoshita T, Nakai M, Wada M, Suetsugu N, Gotoh E. Phototropin2 Contributes to the Chloroplast Avoidance Response at the Chloroplast-Plasma Membrane Interface. PLANT PHYSIOLOGY 2020; 183:304-316. [PMID: 32193212 PMCID: PMC7210631 DOI: 10.1104/pp.20.00059] [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: 01/21/2020] [Accepted: 03/09/2020] [Indexed: 05/31/2023]
Abstract
Blue-light-induced chloroplast movements play an important role in maximizing light utilization for photosynthesis in plants. Under a weak light condition, chloroplasts accumulate to the cell surface to capture light efficiently (chloroplast accumulation response). Conversely, chloroplasts escape from strong light and move to the side wall to reduce photodamage (chloroplast avoidance response). The blue light receptor phototropin (phot) regulates these chloroplast movements and optimizes leaf photosynthesis by controlling other responses in addition to chloroplast movements. Seed plants such as Arabidopsis (Arabidopsis thaliana) have phot1 and phot2. They redundantly mediate phototropism, stomatal opening, leaf flattening, and the chloroplast accumulation response. However, the chloroplast avoidance response is induced by strong blue light and regulated primarily by phot2. Phots are localized mainly on the plasma membrane. However, a substantial amount of phot2 resides on the chloroplast outer envelope. Therefore, differentially localized phot2 might have different functions. To determine the functions of plasma membrane- and chloroplast envelope-localized phot2, we tethered it to these structures with their respective targeting signals. Plasma membrane-localized phot2 regulated phototropism, leaf flattening, stomatal opening, and chloroplast movements. Chloroplast envelope-localized phot2 failed to mediate phototropism, leaf flattening, and the chloroplast accumulation response but partially regulated the chloroplast avoidance response and stomatal opening. Based on the present and previous findings, we propose that phot2 localized at the interface between the plasma membrane and the chloroplasts is required for the chloroplast avoidance response and possibly for stomatal opening as well.
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Affiliation(s)
- Kazuhiro Ishishita
- Graduate School of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
| | - Takeshi Higa
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Hidekazu Tanaka
- Graduate School of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
| | - Shin-Ichiro Inoue
- Graduate School of Sciences, Nagoya University, Aichi 464-8602, Japan
| | - Aeri Chung
- Graduate School of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
| | | | | | | | - Masato Nakai
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Masamitsu Wada
- Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Noriyuki Suetsugu
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Eiji Gotoh
- Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
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31
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Sheahan MB, Collings DA, Rose RJ, McCurdy DW. ACTIN7 Is Required for Perinuclear Clustering of Chloroplasts during Arabidopsis Protoplast Culture. PLANTS 2020; 9:plants9020225. [PMID: 32050601 PMCID: PMC7076399 DOI: 10.3390/plants9020225] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 01/28/2020] [Accepted: 02/07/2020] [Indexed: 11/16/2022]
Abstract
In Arabidopsis, the actin gene family comprises eight expressed and two non-expressed ACTIN (ACT) genes. Of the eight expressed isoforms, ACT2, ACT7, and ACT8 are differentially expressed in vegetative tissues and may perform specific roles in development. Using tobacco mesophyll protoplasts, we previously demonstrated that actin-dependent clustering of chloroplasts around the nucleus prior to cell division ensures unbiased chloroplast inheritance. Here, we report that actin-dependent chloroplast clustering in Arabidopsis mesophyll protoplasts is defective in act7 mutants, but not act2-1 or act8-2. ACT7 expression was upregulated during protoplast culture whereas ACT2 and ACT8 expression did not substantially change. In act2-1, ACT7 expression increased in response to loss of ACT2, whereas in act7-1, neither ACT2 nor ACT8 expression changed appreciably in response to the absence of ACT7. Semi-quantitative immunoblotting revealed increased actin concentrations during culture, although total actin in act7-1 was only two-thirds that of wild-type or act2-1 after 96 h culture. Over-expression of ACT2 and ACT8 under control of ACT7 regulatory sequences restored normal levels of chloroplast clustering. These results are consistent with a requirement for ACT7 in actin-dependent chloroplast clustering due to reduced levels of actin protein and gene induction in act7 mutants, rather than strong functional specialization of the ACT7 isoform.
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Najeeb S, Ali J, Mahender A, Pang Y, Zilhas J, Murugaiyan V, Vemireddy LR, Li Z. Identification of main-effect quantitative trait loci (QTLs) for low-temperature stress tolerance germination- and early seedling vigor-related traits in rice ( Oryza sativa L.). MOLECULAR BREEDING : NEW STRATEGIES IN PLANT IMPROVEMENT 2020; 40:10. [PMID: 31975784 PMCID: PMC6944268 DOI: 10.1007/s11032-019-1090-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 12/12/2019] [Indexed: 05/09/2023]
Abstract
An attempt was made in the current study to identify the main-effect and co-localized quantitative trait loci (QTLs) for germination and early seedling growth traits under low-temperature stress (LTS) conditions in rice. The plant material used in this study was an early backcross population of 230 introgression lines (ILs) in BCIF7 generation derived from the Weed Tolerant Rice-1 (WTR-1) (as the recipient) and Haoannong (HNG) (as the donor). Genetic analyses of LTS tolerance revealed a total of 27 main-effect quantitative trait loci (M-QTLs) mapped on 12 chromosomes. These QTLs explained more than 10% of phenotypic variance (PV), and average PV of 12.71% while employing 704 high-quality SNP markers. Of these 27 QTLs distributed on 12 chromosomes, 11 were associated with low-temperature germination (LTG), nine with low-temperature germination stress index (LTGS), five with root length stress index (RLSI), and two with biomass stress index (BMSI) QTLs, shoot length stress index (SLSI) and root length stress index (RLSI), seven with seed vigor index (SVI), and single QTL with root length (RL). Among them, five significant major QTLs (qLTG(I) 1 , qLTGS(I) 1-2 , qLTG(I) 5 , qLTGS(I) 5 , and qLTG(I) 7 ) mapped on chromosomes 1, 5, and 7 were associated with LTG and LTGS traits and the PV explained ranged from 16 to 23.3%. The genomic regions of these QTLs were co-localized with two to six QTLs. Most of the QTLs were growth stage-specific and found to harbor QTLs governing multiple traits. Eight chromosomes had more than four QTLs and were clustered together and designated as promising LTS tolerance QTLs (qLTTs), as qLTT 1 , qLTT 2 , qLTT 3 , qLTT 5 , qLTT 6 , qLTT 8 , qLTT 9 , and qLTT 11 . A total of 16 putative candidate genes were identified in the major M-QTLs and co-localized QTL regions distributed on different chromosomes. Overall, these significant genomic regions of M-QTLs are responsible for multiple traits and this suggested that these could serve as the best predictors of LTS tolerance at germination and early seedling growth stages. Furthermore, it is necessary to fine-map these regions and to find functional markers for marker-assisted selection in rice breeding programs for cold tolerance.
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Affiliation(s)
- S. Najeeb
- Rice Breeding Platform, International Rice Research Institute (IRRI), 4031 Los Baños, Laguna Philippines
- Mountain Research Centre for Field Crops, Sher-e-Kashmir University of Agricultural Science & Technology (SKAUST), Khudwani, Kashmir 190025 India
| | - J. Ali
- Rice Breeding Platform, International Rice Research Institute (IRRI), 4031 Los Baños, Laguna Philippines
| | - A. Mahender
- Rice Breeding Platform, International Rice Research Institute (IRRI), 4031 Los Baños, Laguna Philippines
| | - Y.L. Pang
- State Key Laboratory of Crop Biology, College of Agronomy, Shandong Agricultural University, Taian, 271018 People’s Republic of China
| | - J. Zilhas
- Rice Breeding Platform, International Rice Research Institute (IRRI), 4031 Los Baños, Laguna Philippines
| | - V. Murugaiyan
- Rice Breeding Platform, International Rice Research Institute (IRRI), 4031 Los Baños, Laguna Philippines
- Plant Nutrition, Institute of Crop Sciences and Resource Conservation (INRES), University of Bonn, 53012 Bonn, Germany
| | - Lakshminarayana R. Vemireddy
- Department of Genetics and Plant Breeding, Sri Venkateswara Agricultural College, Acharya NG Ranga Agricultural University, Tirupati, Andhra Pradesh 517502 India
| | - Z. Li
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100081 People’s Republic of China
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Howard MM, Bae A, Königer M. The importance of chloroplast movement, nonphotochemical quenching, and electron transport rates in light acclimation and tolerance to high light in Arabidopsis thaliana. AMERICAN JOURNAL OF BOTANY 2019; 106:1444-1453. [PMID: 31647579 DOI: 10.1002/ajb2.1378] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 09/10/2019] [Indexed: 06/10/2023]
Abstract
PREMISE While essential for photosynthesis, excess light can damage plants. We investigated how growth light conditions affect two photoprotective strategies, chloroplast movement and nonphotochemical quenching (NPQ), as well as electron transport rates (ETR), and the relative importance of these processes in the short-term stress tolerance of Arabidopsis thaliana. METHODS We grew wild-type (WT) and mutant plants with impaired chloroplast movement (phot1, phot2, phot1 phot2, chup1) or NPQ (npq1) at low (160 μmol photons m-2 s-1 ) or intermediate light (400 μmol photons m-2 s-1 ) before quantifying transmission changes due to chloroplast movement, NPQ, ETR, and the ability to recover from a short-term high-light treatment. RESULTS Plants with impaired chloroplast avoidance movement (phot2, phot1 phot2, chup1) did not recover as well from a short-term high light treatment as the WT or npq1 and phot1 mutants. Plants grown at intermediate light recovered more completely from the same stress treatment regardless of their genotype and despite reduced degrees of transmission changes due to chloroplast movement. This result was due in part to all genotypes having up to a 2-fold increase in ETRmax and a slight increase in NPQmax . CONCLUSIONS Growth light conditions affect which mechanisms are important in dealing with short-term high-light stress. The chloroplast avoidance response is important for low-light-grown plants, while increases in ETRmax and NPQmax allow plants grown at intermediate light intensities to avoid being damaged.
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Affiliation(s)
- Mia M Howard
- Department of Biological Sciences, Wellesley College, Wellesley, MA, 02481, USA
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Andrea Bae
- Department of Biological Sciences, Wellesley College, Wellesley, MA, 02481, USA
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Martina Königer
- Department of Biological Sciences, Wellesley College, Wellesley, MA, 02481, USA
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Yang Y, Chen B, Dang X, Zhu L, Rao J, Ren H, Lin C, Qin Y, Lin D. Arabidopsis IPGA1 is a microtubule-associated protein essential for cell expansion during petal morphogenesis. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:5231-5243. [PMID: 31198941 PMCID: PMC6793458 DOI: 10.1093/jxb/erz284] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 06/05/2019] [Indexed: 05/23/2023]
Abstract
Unlike animal cells, plant cells do not possess centrosomes that serve as microtubule organizing centers; how microtubule arrays are organized throughout plant morphogenesis remains poorly understood. We report here that Arabidopsis INCREASED PETAL GROWTH ANISOTROPY 1 (IPGA1), a previously uncharacterized microtubule-associated protein, regulates petal growth and shape by affecting cortical microtubule organization. Through a genetic screen, we showed that IPGA1 loss-of-function mutants displayed a phenotype of longer and narrower petals, as well as increased anisotropic cell expansion of the petal epidermis in the late phases of flower development. Map-based cloning studies revealed that IPGA1 encodes a previously uncharacterized protein that colocalizes with and directly binds to microtubules. IPGA1 plays a negative role in the organization of cortical microtubules into parallel arrays oriented perpendicular to the axis of cell elongation, with the ipga1-1 mutant displaying increased microtubule ordering in petal abaxial epidermal cells. The IPGA1 family is conserved among land plants and its homologs may have evolved to regulate microtubule organization. Taken together, our findings identify IPGA1 as a novel microtubule-associated protein and provide significant insights into IPGA1-mediated microtubule organization and petal growth anisotropy.
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Affiliation(s)
- Yanqiu Yang
- College of Life Science, Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Binqinq Chen
- College of Life Science, Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xie Dang
- College of Life Science, Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Lab of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning, China
| | - Lilan Zhu
- College of Life Science, Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jinqiu Rao
- College of Life Science, Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Huibo Ren
- College of Life Science, Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Chentao Lin
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Yuan Qin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Lab of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Center for Genomics and Biotechnology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Deshu Lin
- College of Life Science, Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Lab of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning, China
- Correspondence:
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Sakata M, Kimura S, Fujii Y, Sakai T, Kodama Y. Relationship between relocation of phototropin to the chloroplast periphery and the initiation of chloroplast movement in Marchantia polymorpha. PLANT DIRECT 2019; 3:e00160. [PMID: 31468027 PMCID: PMC6710648 DOI: 10.1002/pld3.160] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 07/23/2019] [Accepted: 07/31/2019] [Indexed: 05/02/2023]
Abstract
The blue-light photoreceptor kinase phototropin (phot) mediates chloroplast movement in response to light and temperature. Phot predominantly localizes at the plasma membrane, but also resides in the cytosol and the chloroplast periphery. Although the phot localized to the chloroplast periphery is thought to mediate chloroplast movement, the localization mechanism is unknown. In this study, we found that chloroplast movement does not occur in 0-day-old gemma cells of the liverwort Marchantia polymorpha but that the movement is induced in 1-day-old gemmaling cells. Along with this physiological change, the subcellular localization of phot also changed: In 0-day-old gemma cells, phot localized at the plasma membrane and the cytosol, but in 1-day-old gemmaling cells, the phot disappeared from the cytosol and appeared at the chloroplast periphery. When the relocalization was tracked using a photoconvertible fluorescent protein, the cytosolic phot relocated to the plasma membrane, and the plasma membrane-resident phot relocated to the chloroplast periphery. The blue-light-dependent activation of phot kinase activity enhanced this relocalization. Mutated phot deficient in blue-light reception or kinase activity had a severely reduced ability to localize at the chloroplast periphery. These findings suggest that photoactivated phot localizes at the chloroplast periphery to initiate chloroplast movement.
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Affiliation(s)
- Momoko Sakata
- Center for Bioscience Research and EducationUtsunomiya UniversityTochigiJapan
- Graduate School of Agricultural ScienceUtsunomiya UniversityTochigiJapan
| | - Shun Kimura
- Center for Bioscience Research and EducationUtsunomiya UniversityTochigiJapan
- Graduate School of Agricultural ScienceUtsunomiya UniversityTochigiJapan
| | - Yuta Fujii
- Center for Bioscience Research and EducationUtsunomiya UniversityTochigiJapan
- United Graduate School of Agricultural ScienceTokyo University of Agriculture and TechnologyTokyoJapan
| | - Takamasa Sakai
- Department of Bioengineering, School of EngineeringThe University of TokyoTokyoJapan
| | - Yutaka Kodama
- Center for Bioscience Research and EducationUtsunomiya UniversityTochigiJapan
- Graduate School of Agricultural ScienceUtsunomiya UniversityTochigiJapan
- United Graduate School of Agricultural ScienceTokyo University of Agriculture and TechnologyTokyoJapan
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36
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Wada M. Light-dependent spatiotemporal control of plant cell development and organelle movement in fern gametophytes. Microscopy (Oxf) 2019; 68:13-36. [PMID: 30576547 DOI: 10.1093/jmicro/dfy143] [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: 09/18/2018] [Revised: 10/30/2018] [Accepted: 11/24/2018] [Indexed: 11/12/2022] Open
Abstract
The haploid gametophyte generation of ferns is an excellent experimental material for cell biology studies because of its simple structure and high sensitivity to light. Each step of the developmental process, such as cell growth, cell cycle and the direction of cell division, is controlled, step by step, by light, unlike what happens in complex seed plant tissues. To perform analyses at the cell or organelle level, we have developed special tools, instruments and techniques, such as a cuvette suitable for repeated centrifugation in particular directions, microbeam irradiators for partial cell irradiation and single-cell ligation technique to create enucleated cells. Some of our main discoveries are as follows: (1) changes in the intracellular position of the nucleus in long protonemal cells by centrifugation revealed that the nuclear position or a factor(s) that is/are co-centrifuged with the nucleus is important for the decision regarding the place of the formation of preprophase bands and the timing of their disappearance, which determines the position where the new cell wall attaches to the mother cell wall; (2) even within a single cell, various phenomena could be induced by blue or red light, with the localization of the blue or red light receptors being different depending on the phenomenon; (3) de novo mRNA synthesis is not involved in the signal transduction pathways underlying light-induced chloroplast movements. In this review article, various microscopic techniques, in addition to the results of physiology studies in fern gametophytes, are described.
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Affiliation(s)
- Masamitsu Wada
- Department of Biological science, Graduate School of Science, Tokyo Metropolitan University, Tokyo, Japan
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Sparkes I. Lessons from optical tweezers: quantifying organelle interactions, dynamics and modelling subcellular events. CURRENT OPINION IN PLANT BIOLOGY 2018; 46:55-61. [PMID: 30081386 DOI: 10.1016/j.pbi.2018.07.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 07/06/2018] [Accepted: 07/13/2018] [Indexed: 05/24/2023]
Abstract
Optical tweezers enable users to physically trap organelles and move them laterally within the plant cell. Recent advances have highlighted physical interactions between functionally related organelle pairs, such as ER-Golgi and peroxisome-chloroplast, and have shown how organelle positioning affects plant growth. Quantification of these processes has provided insight into the force components which ultimately drive organelle movement and positioning in plant cells. Application of optical tweezers has therefore revolutionised our understanding of plant organelle dynamics.
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Affiliation(s)
- Imogen Sparkes
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK.
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38
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Gotoh E, Suetsugu N, Yamori W, Ishishita K, Kiyabu R, Fukuda M, Higa T, Shirouchi B, Wada M. Chloroplast Accumulation Response Enhances Leaf Photosynthesis and Plant Biomass Production. PLANT PHYSIOLOGY 2018; 178:1358-1369. [PMID: 30266749 PMCID: PMC6236601 DOI: 10.1104/pp.18.00484] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 09/23/2018] [Indexed: 05/16/2023]
Abstract
Under high light intensity, chloroplasts avoid absorbing excess light by moving to anticlinal cell walls (avoidance response), but under low light intensity, chloroplasts accumulate along periclinal cell walls (accumulation response). In most plant species, these responses are induced by blue light and are mediated by the blue light photoreceptor, phototropin, which also regulates phototropism, leaf flattening, and stomatal opening. These phototropin-mediated responses could enhance photosynthesis and biomass production. Here, using various Arabidopsis (Arabidopsis thaliana) mutants deficient in chloroplast movement, we demonstrated that the accumulation response enhances leaf photosynthesis and plant biomass production. Conspicuously, phototropin2 mutant plants specifically defective in the avoidance response but not in other phototropin-mediated responses displayed a constitutive accumulation response irrespective of light intensities, enhanced leaf photosynthesis, and increased plant biomass production. Therefore, our findings provide clear experimental evidence of the importance of the chloroplast accumulation response in leaf photosynthesis and biomass production.
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Affiliation(s)
- Eiji Gotoh
- Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan
| | - Noriyuki Suetsugu
- Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Wataru Yamori
- Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan
| | | | - Ryota Kiyabu
- Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan
| | - Masako Fukuda
- Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan
| | - Takeshi Higa
- Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Bungo Shirouchi
- Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan
| | - Masamitsu Wada
- Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan
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39
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DeBlasio SL, Xu Y, Johnson RS, Rebelo AR, MacCoss MJ, Gray SM, Heck M. The Interaction Dynamics of Two Potato Leafroll Virus Movement Proteins Affects Their Localization to the Outer Membranes of Mitochondria and Plastids. Viruses 2018; 10:E585. [PMID: 30373157 PMCID: PMC6265731 DOI: 10.3390/v10110585] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 10/19/2018] [Accepted: 10/19/2018] [Indexed: 12/15/2022] Open
Abstract
The Luteoviridae is an agriculturally important family of viruses whose replication and transport are restricted to plant phloem. Their genomes encode for four proteins that regulate viral movement. These include two structural proteins that make up the capsid and two non-structural proteins known as P3a and P17. Little is known about how these proteins interact with each other and the host to coordinate virus movement within and between cells. We used quantitative, affinity purification-mass spectrometry to show that the P3a protein of Potato leafroll virus complexes with virus and that this interaction is partially dependent on P17. Bimolecular complementation assays (BiFC) were used to validate that P3a and P17 self-interact as well as directly interact with each other. Co-localization with fluorescent-based organelle markers demonstrates that P3a directs P17 to the mitochondrial outer membrane while P17 regulates the localization of the P3a-P17 heterodimer to plastids. Residues in the C-terminus of P3a were shown to regulate P3a association with host mitochondria by using mutational analysis and also varying BiFC tag orientation. Collectively, our work reveals that the PLRV movement proteins play a game of intracellular hopscotch along host organelles to transport the virus to the cell periphery.
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Affiliation(s)
- Stacy L DeBlasio
- United States Department of Agriculture, Biological Integrated Pest Management Research Unit, Robert W. Holley Center for Agriculture and Health, 538 Tower Road, Ithaca, NY 14853, USA.
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA.
| | - Yi Xu
- Section of Plant Pathology and Plant-Microbe Biology, School of Integrated Plant Science, Cornell University, Ithaca, NY 14853, USA.
| | - Richard S Johnson
- Department of Genome Sciences, University of Washington, Seattle WA 98109, USA.
| | - Ana Rita Rebelo
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA.
| | - Michael J MacCoss
- Department of Genome Sciences, University of Washington, Seattle WA 98109, USA.
| | - Stewart M Gray
- United States Department of Agriculture, Biological Integrated Pest Management Research Unit, Robert W. Holley Center for Agriculture and Health, 538 Tower Road, Ithaca, NY 14853, USA.
- Section of Plant Pathology and Plant-Microbe Biology, School of Integrated Plant Science, Cornell University, Ithaca, NY 14853, USA.
| | - Michelle Heck
- United States Department of Agriculture, Biological Integrated Pest Management Research Unit, Robert W. Holley Center for Agriculture and Health, 538 Tower Road, Ithaca, NY 14853, USA.
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA.
- Section of Plant Pathology and Plant-Microbe Biology, School of Integrated Plant Science, Cornell University, Ithaca, NY 14853, USA.
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40
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Perico C, Sparkes I. Plant organelle dynamics: cytoskeletal control and membrane contact sites. THE NEW PHYTOLOGIST 2018; 220:381-394. [PMID: 30078196 DOI: 10.1111/nph.15365] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 06/10/2018] [Indexed: 05/22/2023]
Abstract
Contents Summary 381 I. Introduction 381 II. Basic movement characteristics 382 III. Actin and associated motors, myosins, play a primary role in plant organelle movement and positioning 382 IV. Mechanisms of myosin recruitment: a tightly regulated system? 384 V. Microtubules, associated motors and interplay with actin 386 VI. Role of organelle interactions: tales of tethers 387 VII. Summary model to describe organelle movement in higher plants 390 VIII. Why is organelle movement important? 390 IX. Conclusions and future perspectives 391 Acknowledgements 391 References 391 SUMMARY: Organelle movement and positioning are correlated with plant growth and development. Movement characteristics are seemingly erratic yet respond to external stimuli including pathogens and light. Given these clear correlations, we still do not understand the specific roles that movement plays in these processes. There are few exceptions including organelle inheritance during cell division and photorelocation of chloroplasts to prevent photodamage. The molecular and biophysical components that drive movement can be broken down into cytoskeletal components, motor proteins and tethers, which allow organelles to physically interact with one another. Our understanding of these components and concepts has exploded over the past decade, with recent technological advances allowing an even more in-depth profiling. Here, we provide an overview of the cytoskeletal and tethering components and discuss the mechanisms behind organelle movement in higher plants.
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Affiliation(s)
- Chiara Perico
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Imogen Sparkes
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
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41
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Nuclear movement and positioning in plant cells. Semin Cell Dev Biol 2018; 82:17-24. [DOI: 10.1016/j.semcdb.2017.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 10/03/2017] [Accepted: 10/03/2017] [Indexed: 12/15/2022]
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Mullineaux PM, Exposito-Rodriguez M, Laissue PP, Smirnoff N. ROS-dependent signalling pathways in plants and algae exposed to high light: Comparisons with other eukaryotes. Free Radic Biol Med 2018; 122:52-64. [PMID: 29410363 DOI: 10.1016/j.freeradbiomed.2018.01.033] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 01/27/2018] [Accepted: 01/31/2018] [Indexed: 01/09/2023]
Abstract
Like all aerobic organisms, plants and algae co-opt reactive oxygen species (ROS) as signalling molecules to drive cellular responses to changes in their environment. In this respect, there is considerable commonality between all eukaryotes imposed by the constraints of ROS chemistry, similar metabolism in many subcellular compartments, the requirement for a high degree of signal specificity and the deployment of thiol peroxidases as transducers of oxidising equivalents to regulatory proteins. Nevertheless, plants and algae carry out specialised signalling arising from oxygenic photosynthesis in chloroplasts and photoautotropism, which often induce an imbalance between absorption of light energy and the capacity to use it productively. A key means of responding to this imbalance is through communication of chloroplasts with the nucleus to adjust cellular metabolism. Two ROS, singlet oxygen (1O2) and hydrogen peroxide (H2O2), initiate distinct signalling pathways when photosynthesis is perturbed. 1O2, because of its potent reactivity means that it initiates but does not transduce signalling. In contrast, the lower reactivity of H2O2 means that it can also be a mobile messenger in a spatially-defined signalling pathway. How plants translate a H2O2 message to bring about changes in gene expression is unknown and therefore, we draw on information from other eukaryotes to propose a working hypothesis. The role of these ROS generated in other subcellular compartments of plant cells in response to HL is critically considered alongside other eukaryotes. Finally, the responses of animal cells to oxidative stress upon high irradiance exposure is considered for new comparisons between plant and animal cells.
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Affiliation(s)
- Philip M Mullineaux
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK.
| | | | | | - Nicholas Smirnoff
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
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43
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Arabidopsis vegetative actin isoforms, AtACT2 and AtACT7, generate distinct filament arrays in living plant cells. Sci Rep 2018. [PMID: 29531328 PMCID: PMC5847576 DOI: 10.1038/s41598-018-22707-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Flowering plants express multiple actin isoforms. Previous studies suggest that individual actin isoforms have specific functions; however, the subcellular localization of actin isoforms in plant cells remains obscure. Here, we transiently expressed and observed major Arabidopsis vegetative actin isoforms, AtACT2 and AtACT7, as fluorescent-fusion proteins. By optimizing the linker sequence between fluorescent protein and actin, we succeeded in observing filaments that contained these expressed actin isoforms fused with green fluorescent protein (GFP) in Arabidopsis protoplasts. Different colored fluorescent proteins fused with AtACT2 and AtACT7 and co-expressed in Nicotiana benthamiana mesophyll cells co-polymerized in a segregated manner along filaments. In epidermal cells, surprisingly, AtACT2 and AtACT7 tended to polymerize into different types of filaments. AtACT2 was incorporated into thinner filaments, whereas AtACT7 was incorporated into thick bundles. We conclude that different actin isoforms are capable of constructing unique filament arrays, depending on the cell type or tissue. Interestingly, staining patterns induced by two indirect actin filament probes, Lifeact and mTalin1, were different between filaments containing AtACT2 and those containing AtACT7. We suggest that filaments containing different actin isoforms bind specific actin-binding proteins in vivo, since the two probes comprise actin-binding domains from different actin-binding proteins.
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44
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Christie JM, Suetsugu N, Sullivan S, Wada M. Shining Light on the Function of NPH3/RPT2-Like Proteins in Phototropin Signaling. PLANT PHYSIOLOGY 2018; 176:1015-1024. [PMID: 28720608 PMCID: PMC5813532 DOI: 10.1104/pp.17.00835] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 07/12/2017] [Indexed: 05/05/2023]
Abstract
NRL proteins coordinate different aspects of phototropin signaling through signaling processes that are conserved in land plants and algae.
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Affiliation(s)
- John M Christie
- Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Noriyuki Suetsugu
- Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Stuart Sullivan
- Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Masamitsu Wada
- Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan
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Abstract
ABSTRACT
Plants are sessile and require diverse strategies to adapt to fluctuations in the surrounding light conditions. Consequently, the photorelocation movement of chloroplasts is essential to prevent damages that are induced by intense light (avoidance response) and to ensure efficient photosynthetic activities under weak light conditions (accumulation response). The mechanisms that underlie chloroplast movements have been revealed through analysis of the behavior of individual chloroplasts and it has been found that these organelles can move in any direction without turning. This implies that any part of the chloroplast periphery can function as the leading or trailing edge during movement. This ability is mediated by a special structure, which consists of short actin filaments that are polymerized at the leading edge of moving chloroplasts and are specifically localized in the space between the chloroplast and the plasma membrane, and is called chloroplast-actin. In addition, several of the genes that encode proteins that are involved in chloroplast-actin polymerization or maintenance have been identified. In this Review, we discuss the mechanisms that regulate chloroplast movements through polymerization of the chloroplast-actin and propose a model for actin-driven chloroplast photorelocation movement.
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Affiliation(s)
- Masamitsu Wada
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Sam-Geun Kong
- Department of Biological Sciences, College of Natural Sciences, Kongju National University, 56 Gongjudaehak-ro Gongju-si, Chungcheongnam-do 32588, Republic of Korea
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46
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Flexas J, Cano FJ, Carriquí M, Coopman RE, Mizokami Y, Tholen D, Xiong D. CO2 Diffusion Inside Photosynthetic Organs. THE LEAF: A PLATFORM FOR PERFORMING PHOTOSYNTHESIS 2018. [DOI: 10.1007/978-3-319-93594-2_7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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47
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Paez-Garcia A, Sparks JA, de Bang L, Blancaflor EB. Plant Actin Cytoskeleton: New Functions from Old Scaffold. PLANT CELL MONOGRAPHS 2018. [DOI: 10.1007/978-3-319-69944-8_6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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48
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Tanaka H, Sato M, Ogasawara Y, Hamashima N, Buchner O, Holzinger A, Toyooka K, Kodama Y. Chloroplast aggregation during the cold-positioning response in the liverwort Marchantia polymorpha. JOURNAL OF PLANT RESEARCH 2017. [PMID: 28634853 DOI: 10.1007/s10265-017-0958-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Under low-light conditions, chloroplasts localize along periclinal cell walls at temperatures near 20 °C, but they localize along anticlinal cell walls near 5 °C. This phenomenon is known as the cold-positioning response. We previously showed that chloroplasts move as aggregates rather than individually during the cold-positioning response in the fern Adiantum capillus-veneris. This observation suggested that chloroplasts physically interact with each other during the cold-positioning response. However, the physiological processes underlying chloroplast aggregation are unclear. In this report, we characterized chloroplast aggregation during the cold-positioning response in the liverwort Marchantia polymorpha. Confocal laser microscopy observations of transgenic liverwort plants expressing a fluorescent fusion protein that localizes to the chloroplast outer envelope membrane (OEP7-Citrine) showed that neighboring chloroplast membranes did not fuse during the cold-positioning response. Transmission electron microscopy analysis revealed that a distance of at least 10 nm was maintained between neighboring chloroplasts during aggregation. These results indicate that aggregated chloroplasts do not fuse, but maintain a distance of at least 10 nm from each other during the cold-positioning response.
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Affiliation(s)
- Hiroyuki Tanaka
- Center for Bioscience Research and Education, Utsunomiya University, Tochigi, 321-8505, Japan
- Collaboration Center for Research and Development, Utsunomiya University, Tochigi, 321-8585, Japan
| | - Mayuko Sato
- Center for Sustainable Resource Science, RIKEN, Kanagawa, 230-0045, Japan
| | - Yuka Ogasawara
- Center for Bioscience Research and Education, Utsunomiya University, Tochigi, 321-8505, Japan
| | - Noriko Hamashima
- Center for Bioscience Research and Education, Utsunomiya University, Tochigi, 321-8505, Japan
| | - Othmar Buchner
- Institute of Botany, University of Innsbruck, 6020, Innsbruck, Austria
| | - Andreas Holzinger
- Institute of Botany, University of Innsbruck, 6020, Innsbruck, Austria
| | - Kiminori Toyooka
- Center for Sustainable Resource Science, RIKEN, Kanagawa, 230-0045, Japan
| | - Yutaka Kodama
- Center for Bioscience Research and Education, Utsunomiya University, Tochigi, 321-8505, Japan.
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49
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Suetsugu N, Higa T, Wada M. Ferns, mosses and liverworts as model systems for light-mediated chloroplast movements. PLANT, CELL & ENVIRONMENT 2017; 40:2447-2456. [PMID: 27859339 DOI: 10.1111/pce.12867] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/03/2016] [Accepted: 11/07/2016] [Indexed: 05/05/2023]
Abstract
Light-induced chloroplast movement is found in most plant species, including algae and land plants. In land plants with multiple small chloroplasts, under weak light conditions, the chloroplasts move towards the light and accumulate on the periclinal cell walls to efficiently perceive light for photosynthesis (the accumulation response). Under strong light conditions, chloroplasts escape from light to avoid photodamage (the avoidance response). In most plant species, blue light induces chloroplast movement, and phototropin receptor kinases are the blue light receptors. Molecular mechanisms for photoreceptors, signal transduction and chloroplast motility systems are being studied using the model plant Arabidopsis thaliana. However, to further understand the molecular mechanisms and evolutionary history of chloroplast movement in green plants, analyses using other plant systems are required. Here, we review recent works on chloroplast movement in green algae, liverwort, mosses and ferns that provide new insights on chloroplast movement.
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Affiliation(s)
- Noriyuki Suetsugu
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan
| | - Takeshi Higa
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo, 192-0397, Japan
| | - Masamitsu Wada
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo, 192-0397, Japan
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Sakai Y, Takagi S. Roles of actin cytoskeleton for regulation of chloroplast anchoring. PLANT SIGNALING & BEHAVIOR 2017; 12:e1370163. [PMID: 28829686 PMCID: PMC5647951 DOI: 10.1080/15592324.2017.1370163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 08/16/2017] [Indexed: 06/07/2023]
Abstract
Chloroplasts are known to maintain specific intracellular distribution patterns under specific environmental conditions, enabling the optimal performance of photosynthesis. To this end, chloroplasts are anchored in the cortical cytoplasm. In leaf epidermal cells of aquatic monocot Vallisneria, we recently demonstrated that the anchored chloroplasts are rapidly de-anchored upon irradiation with high-intensity blue light and that the process is probably mediated by the blue-light receptor phototropins. Chloroplast de-anchoring is a necessary step rendering the previously anchored chloroplasts mobile to allow their migration. In this article, based on the results obtained in Vallisneria together with those in other plant species, we briefly discussed possible modes of regulation of chloroplast anchoring and de-anchoring by actin cytoskeleton. The topics include roles of photoreceptor systems, actin-filament-dependent and -independent chloroplast anchoring, and independence of chloroplast de-anchoring from actomyosin and microtubule systems.
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Affiliation(s)
- Yuuki Sakai
- Department of Biological Sciences, Graduate School of Science, Osaka University, Osaka, Japan
| | - Shingo Takagi
- Department of Biological Sciences, Graduate School of Science, Osaka University, Osaka, Japan
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