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Wu XX, Mu WH, Li F, Sun SY, Cui CJ, Kim C, Zhou F, Zhang Y. Cryo-EM structures of the plant plastid-encoded RNA polymerase. Cell 2024; 187:1127-1144.e21. [PMID: 38428393 DOI: 10.1016/j.cell.2024.01.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 12/12/2023] [Accepted: 01/16/2024] [Indexed: 03/03/2024]
Abstract
Chloroplasts are green plastids in the cytoplasm of eukaryotic algae and plants responsible for photosynthesis. The plastid-encoded RNA polymerase (PEP) plays an essential role during chloroplast biogenesis from proplastids and functions as the predominant RNA polymerase in mature chloroplasts. The PEP-centered transcription apparatus comprises a bacterial-origin PEP core and more than a dozen eukaryotic-origin PEP-associated proteins (PAPs) encoded in the nucleus. Here, we determined the cryo-EM structures of Nicotiana tabacum (tobacco) PEP-PAP apoenzyme and PEP-PAP transcription elongation complexes at near-atomic resolutions. Our data show the PEP core adopts a typical fold as bacterial RNAP. Fifteen PAPs bind at the periphery of the PEP core, facilitate assembling the PEP-PAP supercomplex, protect the complex from oxidation damage, and likely couple gene transcription with RNA processing. Our results report the high-resolution architecture of the chloroplast transcription apparatus and provide the structural basis for the mechanistic and functional study of transcription regulation in chloroplasts.
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Affiliation(s)
- Xiao-Xian Wu
- Key Laboratory of Synthetic Biology, Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Wen-Hui Mu
- Key Laboratory of Synthetic Biology, Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Fan Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Shu-Yi Sun
- Key Laboratory of Synthetic Biology, Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chao-Jun Cui
- University of Chinese Academy of Sciences, Beijing 100049, China; Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Chanhong Kim
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Fei Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.
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Garcia E, Koh J, Wu X, Sarkhosh A, Liu T. Tissue-specific proteome profile analysis reveals regulatory and stress responsive networks in passion fruit during storage. Sci Rep 2024; 14:3564. [PMID: 38346991 PMCID: PMC10861471 DOI: 10.1038/s41598-024-52557-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 01/20/2024] [Indexed: 02/15/2024] Open
Abstract
Passiflora edulis, commonly known as passion fruit, is a crop with a fragrant aroma and refreshingly tropical flavor that is a valuable source of antioxidants. It offers a unique opportunity for growers because of its adaptability to tropical and subtropical climates. Passion fruit can be sold in the fresh market or used in value-added products, but its postharvest shelf life has not been well-researched, nor have superior cultivars been well-developed. Understanding the proteins expressed at the tissue level during the postharvest stage can help improve fruit quality and extend shelf life. In this study, we carried out comparative proteomics analysis on four passion fruit tissues, the epicarp, mesocarp, endocarp, and pulp, using multiplexed isobaric tandem mass tag (TMT) labeling quantitation. A total of 3352 proteins were identified, including 295 differentially expressed proteins (DEPs). Of these DEPs, 213 showed a fold increase greater than 1.45 (50 proteins) or a fold decrease less than 0.45 (163 proteins) with different patterns among tissue types. Among the DEPs, there were proteins expressed with functions in oxygen scavenging, lipid peroxidation, response to heat stress, and pathogen resistance. Thirty-six proteins were designated as hypothetical proteins were characterized for potential functions in immunity, cell structure, homeostasis, stress response, protein metabolism and miraculin biosynthesis. This research provides insight into tissue-specific pathways that can be further studied within fruit physiology and postharvest shelf life to aid in implementing effective plant breeding programs. Knowing the tissue-specific function of fruit is essential for improving fruit quality, developing new varieties, identifying health benefits, and optimizing processing techniques.
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Affiliation(s)
- Ellen Garcia
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611, USA
| | - Jin Koh
- The Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL, 32611, USA
| | - Xingbo Wu
- Department of Environmental Horticulture, Tropical Research and Education Center, University of Florida, Homestead, FL, 33031, USA
| | - Ali Sarkhosh
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611, USA.
| | - Tie Liu
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611, USA.
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Bychkov IA, Andreeva AA, Vankova R, Lacek J, Kudryakova NV, Kusnetsov VV. Modified Crosstalk between Phytohormones in Arabidopsis Mutants for PEP-Associated Proteins. Int J Mol Sci 2024; 25:1586. [PMID: 38338865 PMCID: PMC10855609 DOI: 10.3390/ijms25031586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/19/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
Plastid-encoded RNA polymerase (PEP) forms a multisubunit complex in operating chloroplasts, where PEP subunits and a sigma factor are tightly associated with 12 additional nuclear-encoded proteins. Mutants with disrupted genes encoding PEP-associated proteins (PAPs) provide unique tools for deciphering mutual relationships among phytohormones. A block of chloroplast biogenesis in Arabidopsis pap mutants specifying highly altered metabolism in white tissues induced dramatic fluctuations in the content of major phytohormones and their metabolic genes, whereas hormone signaling circuits mostly remained functional. Reprogramming of the expression of biosynthetic and metabolic genes contributed to a greatly increased content of salicylic acid (SA) and a concomitant decrease in 1-aminocyclopropane-1-carboxylic acid (ACC) and oxophytodienoic acid (OPDA), precursors of ethylene and jasmonic acid, respectively, in parallel to reduced levels of abscisic acid (ABA). The lack of differences in the free levels of indole-3-acetic acid (IAA) between the pap mutants and wild-type plants was accompanied by fluctuations in the contents of IAA precursors and conjugated forms as well as multilayered changes in the expression of IAA metabolic genes. Along with cytokinin (CK) overproduction, all of these compensatory changes aim to balance plant growth and defense systems to ensure viability under highly modulated conditions.
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Affiliation(s)
- Ivan A. Bychkov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, Moscow 127276, Russia; (I.A.B.); (A.A.A.); (V.V.K.)
| | - Aleksandra A. Andreeva
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, Moscow 127276, Russia; (I.A.B.); (A.A.A.); (V.V.K.)
| | - Radomira Vankova
- Institute of Experimental Botany, Academy of Sciences CR, Rozvojova 263, 165 02 Prague, Czech Republic; (R.V.); (J.L.)
| | - Jozef Lacek
- Institute of Experimental Botany, Academy of Sciences CR, Rozvojova 263, 165 02 Prague, Czech Republic; (R.V.); (J.L.)
| | - Natalia V. Kudryakova
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, Moscow 127276, Russia; (I.A.B.); (A.A.A.); (V.V.K.)
| | - Victor V. Kusnetsov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, Moscow 127276, Russia; (I.A.B.); (A.A.A.); (V.V.K.)
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Lasorella C, Fortunato S, Dipierro N, Jeran N, Tadini L, Vita F, Pesaresi P, de Pinto MC. Chloroplast-localized GUN1 contributes to the acquisition of basal thermotolerance in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2022; 13:1058831. [PMID: 36618674 PMCID: PMC9813751 DOI: 10.3389/fpls.2022.1058831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
Heat stress (HS) severely affects different cellular compartments operating in metabolic processes and represents a critical threat to plant growth and yield. Chloroplasts are crucial for heat stress response (HSR), signaling to the nucleus the environmental challenge and adjusting metabolic and biosynthetic functions accordingly. GENOMES UNCOUPLED 1 (GUN1), a chloroplast-localized protein, has been recognized as one of the main players of chloroplast retrograde signaling. Here, we investigate HSR in Arabidopsis wild-type and gun1 plantlets subjected to 2 hours of HS at 45°C. In wild-type plants, Reactive Oxygen Species (ROS) accumulate promptly after HS, contributing to transiently oxidize the cellular environment and acting as signaling molecules. After 3 hours of physiological recovery at growth temperature (22°C), the induction of enzymatic and non-enzymatic antioxidants prevents oxidative damage. On the other hand, gun1 mutants fail to induce the oxidative burst immediately after HS and accumulate ROS and oxidative damage after 3 hours of recovery at 22°C, thus resulting in enhanced sensitivity to HS. These data suggest that GUN1 is required to oxidize the cellular environment, participating in the acquisition of basal thermotolerance through the redox-dependent plastid-to-nucleus communication.
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Affiliation(s)
- Cecilia Lasorella
- Department of Bioscience, Biotechnology and Environment University of Bari Aldo Moro, Bari, Italy
| | - Stefania Fortunato
- Department of Bioscience, Biotechnology and Environment University of Bari Aldo Moro, Bari, Italy
| | - Nunzio Dipierro
- Department of Bioscience, Biotechnology and Environment University of Bari Aldo Moro, Bari, Italy
| | - Nicolaj Jeran
- Department of Biosciences, University of Milano, Milano, Italy
| | - Luca Tadini
- Department of Biosciences, University of Milano, Milano, Italy
| | - Federico Vita
- Department of Bioscience, Biotechnology and Environment University of Bari Aldo Moro, Bari, Italy
| | - Paolo Pesaresi
- Department of Biosciences, University of Milano, Milano, Italy
| | - Maria Concetta de Pinto
- Department of Bioscience, Biotechnology and Environment University of Bari Aldo Moro, Bari, Italy
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