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Song C, Li Y, Yang M, Li T, Hou Y, Liu Y, Xu C, Liu J, Millar AH, Wang N, Li L. Protein aggregation in plant mitochondria lacking Lon1 inhibits translation and induces unfolded protein responses. PLANT, CELL & ENVIRONMENT 2024. [PMID: 38988259 DOI: 10.1111/pce.15035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 06/20/2024] [Accepted: 06/27/2024] [Indexed: 07/12/2024]
Abstract
Loss of Lon1 led to stunted plant growth and accumulation of nuclear-encoded mitochondrial proteins including Lon1 substrates. However, an in-depth label-free proteomics quantification of mitochondrial proteins in lon1 revealed that the majority of mitochondrial-encoded proteins decreased in abundance. Additionally, we found that lon1 mutants contained protein aggregates in the mitochondrial that were enriched in metabolic enzymes, ribosomal subunits and PPR-containing proteins of the translation apparatus. These mutants exhibited reduced general mitochondrial translation as well as deficiencies in RNA splicing and editing. These findings support the role of Lon1 in maintaining a functional translational apparatus for mitochondrial-encoded gene translation. Transcriptome analysis of lon1 revealed a mitochondrial unfolded protein response reminiscent of the mitochondrial retrograde signalling dependent on the transcription factor ANAC017. Notably, lon1 mutants exhibited transiently elevated ethylene production, and the shortened hypocotyl observed in lon1 mutants during skotomorphogenesis was partially alleviated by ethylene inhibitors. Furthermore, the short root phenotype was partially ameliorated by introducing a mutation in the ethylene receptor ETR1. Interestingly, the upregulation of only a select few target genes was linked to ETR1-mediated ethylene signalling. Together this provides multiple steps in the link between loss of Lon1 and signalling responses to restore mitochondrial protein homoeostasis in plants.
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Affiliation(s)
- Ce Song
- Frontiers Science Center for Cell Responses, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yuanyuan Li
- Frontiers Science Center for Cell Responses, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, China
| | - Mengmeng Yang
- Frontiers Science Center for Cell Responses, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, China
| | - Tiantian Li
- Frontiers Science Center for Cell Responses, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yuqi Hou
- Frontiers Science Center for Cell Responses, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yinyin Liu
- Frontiers Science Center for Cell Responses, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, China
| | - Chang Xu
- Frontiers Science Center for Cell Responses, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, China
| | - Jinjian Liu
- Key Laboratory of Radiopharmacokinetics for Innovative Drugs, Chinese Academy of Medical Sciences, and Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - A Harvey Millar
- ARC Centre of Excellence in Plant Energy Biology, School of Molecular Science, The University of Western Australia, Crawley, Western Australia, Australia
| | - Ningning Wang
- Frontiers Science Center for Cell Responses, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, China
| | - Lei Li
- Frontiers Science Center for Cell Responses, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, China
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2
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Sayyed A, Chen B, Wang Y, Cao SK, Tan BC. PPR596 Is Required for nad2 Intron Splicing and Complex I Biogenesis in Arabidopsis. Int J Mol Sci 2024; 25:3542. [PMID: 38542518 PMCID: PMC10971677 DOI: 10.3390/ijms25063542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 03/15/2024] [Accepted: 03/16/2024] [Indexed: 04/04/2024] Open
Abstract
Mitochondria are essential organelles that generate energy via oxidative phosphorylation. Plant mitochondrial genome encodes some of the respiratory complex subunits, and these transcripts require accurate processing, including C-to-U RNA editing and intron splicing. Pentatricopeptide repeats (PPR) proteins are involved in various organellar RNA processing events. PPR596, a P-type PPR protein, was previously identified to function in the C-to-U editing of mitochondrial rps3 transcripts in Arabidopsis. Here, we demonstrate that PPR596 functions in the cis-splicing of nad2 intron 3 in mitochondria. Loss of the PPR596 function affects the editing at rps3eU1344SS, impairs nad2 intron 3 splicing and reduces the mitochondrial complex I's assembly and activity, while inducing alternative oxidase (AOX) gene expression. This defect in nad2 intron splicing provides a plausible explanation for the slow growth of the ppr595 mutants. Although a few P-type PPR proteins are involved in RNA C-to-U editing, our results suggest that the primary function of PPR596 is intron splicing.
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Affiliation(s)
| | | | | | | | - Bao-Cai Tan
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China; (A.S.); (B.C.); (Y.W.); (S.-K.C.)
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3
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Li X, Jiang Y. Research Progress of Group II Intron Splicing Factors in Land Plant Mitochondria. Genes (Basel) 2024; 15:176. [PMID: 38397166 PMCID: PMC10887915 DOI: 10.3390/genes15020176] [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: 12/11/2023] [Revised: 01/16/2024] [Accepted: 01/25/2024] [Indexed: 02/25/2024] Open
Abstract
Mitochondria are important organelles that provide energy for the life of cells. Group II introns are usually found in the mitochondrial genes of land plants. Correct splicing of group II introns is critical to mitochondrial gene expression, mitochondrial biological function, and plant growth and development. Ancestral group II introns are self-splicing ribozymes that can catalyze their own removal from pre-RNAs, while group II introns in land plant mitochondria went through degenerations in RNA structures, and thus they lost the ability to self-splice. Instead, splicing of these introns in the mitochondria of land plants is promoted by nuclear- and mitochondrial-encoded proteins. Many proteins involved in mitochondrial group II intron splicing have been characterized in land plants to date. Here, we present a summary of research progress on mitochondrial group II intron splicing in land plants, with a major focus on protein splicing factors and their probable functions on the splicing of mitochondrial group II introns.
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Affiliation(s)
| | - Yueshui Jiang
- School of Life Sciences, Qufu Normal University, Qufu 273165, China;
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4
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Small I, Melonek J, Bohne AV, Nickelsen J, Schmitz-Linneweber C. Plant organellar RNA maturation. THE PLANT CELL 2023; 35:1727-1751. [PMID: 36807982 PMCID: PMC10226603 DOI: 10.1093/plcell/koad049] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 01/05/2023] [Accepted: 01/17/2023] [Indexed: 05/30/2023]
Abstract
Plant organellar RNA metabolism is run by a multitude of nucleus-encoded RNA-binding proteins (RBPs) that control RNA stability, processing, and degradation. In chloroplasts and mitochondria, these post-transcriptional processes are vital for the production of a small number of essential components of the photosynthetic and respiratory machinery-and consequently for organellar biogenesis and plant survival. Many organellar RBPs have been functionally assigned to individual steps in RNA maturation, often specific to selected transcripts. While the catalog of factors identified is ever-growing, our knowledge of how they achieve their functions mechanistically is far from complete. This review summarizes the current knowledge of plant organellar RNA metabolism taking an RBP-centric approach and focusing on mechanistic aspects of RBP functions and the kinetics of the processes they are involved in.
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Affiliation(s)
- Ian Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley 6009, Australia
| | - Joanna Melonek
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley 6009, Australia
| | | | - Jörg Nickelsen
- Department of Molecular Plant Sciences, LMU Munich, 82152 Martinsried, Germany
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5
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Lu K, Li C, Guan J, Liang WH, Chen T, Zhao QY, Zhu Z, Yao S, He L, Wei XD, Zhao L, Zhou LH, Zhao CF, Wang CL, Zhang YD. The PPR-Domain Protein SOAR1 Regulates Salt Tolerance in Rice. RICE (NEW YORK, N.Y.) 2022; 15:62. [PMID: 36463341 PMCID: PMC9719575 DOI: 10.1186/s12284-022-00608-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 11/27/2022] [Indexed: 06/17/2023]
Abstract
Previous studies in Arabidopsis reported that the PPR protein SOAR1 plays critical roles in plant response to salt stress. In this study, we reported that expression of the Arabidopsis SOAR1 (AtSOAR1) in rice significantly enhanced salt tolerance at seedling growth stage and promoted grain productivity under salt stress without affecting plant productivity under non-stressful conditions. The transgenic rice lines expressing AtSOAR1 exhibited increased ABA sensitivity in ABA-induced inhibition of seedling growth, and showed altered transcription and splicing of numerous genes associated with salt stress, which may explain salt tolerance of the transgenic plants. Further, we overexpressed the homologous gene of SOAR1 in rice, OsSOAR1, and showed that transgenic plants overexpressing OsSOAR1 enhanced salt tolerance at seedling growth stage. Five salt- and other abiotic stress-induced SOAR1-like PPRs were also identified. These data showed that the SOAR1-like PPR proteins are positively involved in plant response to salt stress and may be used for crop improvement in rice under salinity conditions through transgenic manipulation.
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Affiliation(s)
- Kai Lu
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, National Center of Technology Innovation for Saline-Alkali Tolerant Rice, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, 210014, Nanjing, China
| | - Cheng Li
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, National Center of Technology Innovation for Saline-Alkali Tolerant Rice, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, 210014, Nanjing, China
| | - Ju Guan
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, National Center of Technology Innovation for Saline-Alkali Tolerant Rice, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, 210014, Nanjing, China
| | - Wen-Hua Liang
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, National Center of Technology Innovation for Saline-Alkali Tolerant Rice, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, 210014, Nanjing, China
| | - Tao Chen
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, National Center of Technology Innovation for Saline-Alkali Tolerant Rice, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, 210014, Nanjing, China
| | - Qing-Yong Zhao
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, National Center of Technology Innovation for Saline-Alkali Tolerant Rice, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, 210014, Nanjing, China
| | - Zhen Zhu
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, National Center of Technology Innovation for Saline-Alkali Tolerant Rice, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, 210014, Nanjing, China
| | - Shu Yao
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, National Center of Technology Innovation for Saline-Alkali Tolerant Rice, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, 210014, Nanjing, China
| | - Lei He
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, National Center of Technology Innovation for Saline-Alkali Tolerant Rice, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, 210014, Nanjing, China
| | - Xiao-Dong Wei
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, National Center of Technology Innovation for Saline-Alkali Tolerant Rice, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, 210014, Nanjing, China
| | - Ling Zhao
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, National Center of Technology Innovation for Saline-Alkali Tolerant Rice, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, 210014, Nanjing, China
| | - Li-Hui Zhou
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, National Center of Technology Innovation for Saline-Alkali Tolerant Rice, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, 210014, Nanjing, China
| | - Chun-Fang Zhao
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, National Center of Technology Innovation for Saline-Alkali Tolerant Rice, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, 210014, Nanjing, China
| | - Cai-Lin Wang
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, National Center of Technology Innovation for Saline-Alkali Tolerant Rice, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, 210014, Nanjing, China
| | - Ya-Dong Zhang
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, National Center of Technology Innovation for Saline-Alkali Tolerant Rice, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, 210014, Nanjing, China.
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6
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MISF2 Encodes an Essential Mitochondrial Splicing Cofactor Required for nad2 mRNA Processing and Embryo Development in Arabidopsis thaliana. Int J Mol Sci 2022; 23:ijms23052670. [PMID: 35269810 PMCID: PMC8910670 DOI: 10.3390/ijms23052670] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 12/20/2022] Open
Abstract
Mitochondria play key roles in cellular energy metabolism in eukaryotes. Mitochondria of most organisms contain their own genome and specific transcription and translation machineries. The expression of angiosperm mtDNA involves extensive RNA-processing steps, such as RNA trimming, editing, and the splicing of numerous group II-type introns. Pentatricopeptide repeat (PPR) proteins are key players in plant organelle gene expression and RNA metabolism. In the present analysis, we reveal the function of the MITOCHONDRIAL SPLICING FACTOR 2 gene (MISF2, AT3G22670) and show that it encodes a mitochondria-localized PPR protein that is crucial for early embryo development in Arabidopsis. Molecular characterization of embryo-rescued misf2 plantlets indicates that the splicing of nad2 intron 1, and thus respiratory complex I biogenesis, are strongly compromised. Moreover, the molecular function seems conserved between MISF2 protein in Arabidopsis and its orthologous gene (EMP10) in maize, suggesting that the ancestor of MISF2/EMP10 was recruited to function in nad2 processing before the monocot-dicot divergence ~200 million years ago. These data provide new insights into the function of nuclear-encoded factors in mitochondrial gene expression and respiratory chain biogenesis during plant embryo development.
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7
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Fan K, Ren Z, Zhang X, Liu Y, Fu J, Qi C, Tatar W, Rasmusson AG, Wang G, Liu Y. The pentatricopeptide repeat protein EMP603 is required for the splicing of mitochondrial Nad1 intron 2 and seed development in maize. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:6933-6948. [PMID: 34279607 DOI: 10.1093/jxb/erab339] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 07/16/2021] [Indexed: 06/13/2023]
Abstract
Intron splicing is an essential event in post-transcriptional RNA processing in plant mitochondria, which requires the participation of diverse nuclear-encoded splicing factors. However, it is presently unclear how these proteins cooperatively take part in the splicing of specific introns. In this study, we characterized a nuclear-encoded mitochondrial P-type pentatricopeptide repeat (PPR) protein named EMP603. This protein is essential for splicing of intron 2 in the Nad1 gene and interacts with the mitochondria-localized DEAD-box RNA helicase PMH2-5140, the RAD52-like proteins ODB1-0814 and ODB1-5061, and the CRM domain-containing protein Zm-mCSF1. Further study revealed that the N-terminal region of EMP603 interacts with the DEAD-box of PMH2-5140, the CRM domain of Zm-mCSF1, and OBD1-5061, but not with OBD1-0814, whereas the PPR domain of EMP603 can interact with ODB1-0814, ODB1-5061, and PMH2-5140, but not with Zm-mCSF1. Defects in EMP603 severely disrupt the assembly and activity of mitochondrial complex I, leading to impaired mitochondrial function, and delayed seed development. The interactions revealed between EMP603 and PMH2-5140, ODB1-0814, ODB1-5061, and Zm-mCSF1 indicate a possible involvement of a dynamic 'spliceosome-like' complex in intron splicing, and may accelerate the elucidation of the intron splicing mechanism in plant mitochondria.
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Affiliation(s)
- Kaijian Fan
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zhenjing Ren
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaofeng Zhang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yan Liu
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Junjie Fu
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Chunlai Qi
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wurinile Tatar
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | | | - Guoying Wang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yunjun Liu
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
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8
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Li X, Sun M, Liu S, Teng Q, Li S, Jiang Y. Functions of PPR Proteins in Plant Growth and Development. Int J Mol Sci 2021; 22:11274. [PMID: 34681932 PMCID: PMC8537650 DOI: 10.3390/ijms222011274] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/14/2021] [Accepted: 10/16/2021] [Indexed: 01/04/2023] Open
Abstract
Pentatricopeptide repeat (PPR) proteins form a large protein family in land plants, with hundreds of different members in angiosperms. In the last decade, a number of studies have shown that PPR proteins are sequence-specific RNA-binding proteins involved in multiple aspects of plant organellar RNA processing, and perform numerous functions in plants throughout their life cycle. Recently, computational and structural studies have provided new insights into the working mechanisms of PPR proteins in RNA recognition and cytidine deamination. In this review, we summarized the research progress on the functions of PPR proteins in plant growth and development, with a particular focus on their effects on cytoplasmic male sterility, stress responses, and seed development. We also documented the molecular mechanisms of PPR proteins in mediating RNA processing in plant mitochondria and chloroplasts.
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Affiliation(s)
- Xiulan Li
- School of Life Sciences, Qufu Normal University, Qufu 273165, China; (M.S.); (S.L.); (Q.T.); (S.L.)
| | | | | | | | | | - Yueshui Jiang
- School of Life Sciences, Qufu Normal University, Qufu 273165, China; (M.S.); (S.L.); (Q.T.); (S.L.)
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9
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Transcriptional Landscape and Splicing Efficiency in Arabidopsis Mitochondria. Cells 2021; 10:cells10082054. [PMID: 34440822 PMCID: PMC8392254 DOI: 10.3390/cells10082054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/23/2021] [Accepted: 07/30/2021] [Indexed: 12/18/2022] Open
Abstract
Plant mitochondrial transcription is initiated from multiple promoters without an apparent motif, which precludes their identification in other species based on sequence comparisons. Even though coding regions take up only a small fraction of plant mitochondrial genomes, deep RNAseq studies uncovered that these genomes are fully or nearly fully transcribed with significantly different RNA read depth across the genome. Transcriptomic analysis can be a powerful tool to understand the transcription process in diverse angiosperms, including the identification of potential promoters and co-transcribed genes or to study the efficiency of intron splicing. In this work, we analyzed the transcriptional landscape of the Arabidopsis mitochondrial genome (mtDNA) based on large-scale RNA sequencing data to evaluate the use of RNAseq to study those aspects of the transcription process. We found that about 98% of the Arabidopsis mtDNA is transcribed with highly different RNA read depth, which was elevated in known genes. The location of a sharp increase in RNA read depth upstream of genes matched the experimentally identified promoters. The continuously high RNA read depth across two adjacent genes agreed with the known co-transcribed units in Arabidopsis mitochondria. Most intron-containing genes showed a high splicing efficiency with no differences between cis and trans-spliced introns or between genes with distinct splicing mechanisms. Deep RNAseq analyses of diverse plant species will be valuable to recognize general and lineage-specific characteristics related to the mitochondrial transcription process.
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10
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Wang X, An Y, Xu P, Xiao J. Functioning of PPR Proteins in Organelle RNA Metabolism and Chloroplast Biogenesis. FRONTIERS IN PLANT SCIENCE 2021; 12:627501. [PMID: 33633768 PMCID: PMC7900629 DOI: 10.3389/fpls.2021.627501] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 01/04/2021] [Indexed: 05/05/2023]
Abstract
The pentatricopeptide repeat (PPR) proteins constitute one of the largest nuclear-encoded protein families in higher plants, with over 400 members in most sequenced plant species. The molecular functions of these proteins and their physiological roles during plant growth and development have been widely studied. Generally, there is mounting evidence that PPR proteins are involved in the post-transcriptional regulation of chloroplast and/or mitochondrial genes, including RNA maturation, editing, intron splicing, transcripts' stabilization, and translation initiation. The cooperative action of RNA metabolism has profound effects on the biogenesis and functioning of both chloroplasts and mitochondria and, consequently, on the photosynthesis, respiration, and development of plants and their environmental responses. In this review, we summarize the latest research on PPR proteins, specifically how they might function in the chloroplast, by documenting their mechanism of molecular function, their corresponding RNA targets, and their specific effects upon chloroplast biogenesis and host organisms.
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Affiliation(s)
- Xinwei Wang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Yaqi An
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Pan Xu
- State Key Laboratory of Grassland Agro-Ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Jianwei Xiao
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
- *Correspondence: Jianwei Xiao,
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11
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Sun Y, Xie M, Xu Z, Chan KC, Zhong JY, Fan K, Wong-Bajracharya J, Lam HM, Lim BL. Differential RNA Editing and Intron Splicing in Soybean Mitochondria during Nodulation. Int J Mol Sci 2020; 21:E9378. [PMID: 33317061 PMCID: PMC7764374 DOI: 10.3390/ijms21249378] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/12/2022] Open
Abstract
Nitrogen fixation in soybean consumes a tremendous amount of energy, leading to substantial differences in energy metabolism and mitochondrial activities between nodules and uninoculated roots. While C-to-U RNA editing and intron splicing of mitochondrial transcripts are common in plant species, their roles in relation to nodule functions are still elusive. In this study, we performed RNA-seq to compare transcript profiles and RNA editing of mitochondrial genes in soybean nodules and roots. A total of 631 RNA editing sites were identified on mitochondrial transcripts, with 12% or 74 sites differentially edited among the transcripts isolated from nodules, stripped roots, and uninoculated roots. Eight out of these 74 differentially edited sites are located on the matR transcript, of which the degrees of RNA editing were the highest in the nodule sample. The degree of mitochondrial intron splicing was also examined. The splicing efficiencies of several introns in nodules and stripped roots were higher than in uninoculated roots. These include nad1 introns 2/3/4, nad4 intron 3, nad5 introns 2/3, cox2 intron 1, and ccmFc intron 1. A greater splicing efficiency of nad4 intron 1, a higher NAD4 protein abundance, and a reduction in supercomplex I + III2 were also observed in nodules, although the causal relationship between these observations requires further investigation.
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Affiliation(s)
- Yuzhe Sun
- School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China; (Y.S.); (Z.X.); (K.C.C.); (J.Y.Z.)
| | - Min Xie
- Center for Soybean Research of the State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, China; (M.X.); (K.F.); (J.W.-B.)
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Zhou Xu
- School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China; (Y.S.); (Z.X.); (K.C.C.); (J.Y.Z.)
| | - Koon Chuen Chan
- School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China; (Y.S.); (Z.X.); (K.C.C.); (J.Y.Z.)
| | - Jia Yi Zhong
- School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China; (Y.S.); (Z.X.); (K.C.C.); (J.Y.Z.)
| | - Kejing Fan
- Center for Soybean Research of the State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, China; (M.X.); (K.F.); (J.W.-B.)
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Johanna Wong-Bajracharya
- Center for Soybean Research of the State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, China; (M.X.); (K.F.); (J.W.-B.)
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Hon-Ming Lam
- Center for Soybean Research of the State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, China; (M.X.); (K.F.); (J.W.-B.)
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Boon Leong Lim
- School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China; (Y.S.); (Z.X.); (K.C.C.); (J.Y.Z.)
- Center for Soybean Research of the State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, China; (M.X.); (K.F.); (J.W.-B.)
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