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Krämer C, Boehm CR, Liu J, Ting MKY, Hertle AP, Forner J, Ruf S, Schöttler MA, Zoschke R, Bock R. Removal of the large inverted repeat from the plastid genome reveals gene dosage effects and leads to increased genome copy number. NATURE PLANTS 2024; 10:923-935. [PMID: 38802561 PMCID: PMC11208156 DOI: 10.1038/s41477-024-01709-9] [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: 11/22/2023] [Accepted: 04/24/2024] [Indexed: 05/29/2024]
Abstract
The chloroplast genomes of most plants and algae contain a large inverted repeat (IR) region that separates two single-copy regions and harbours the ribosomal RNA operon. We have addressed the functional importance of the IR region by removing an entire copy of the 25.3-kb IR from the tobacco plastid genome. Using plastid transformation and subsequent selectable marker gene elimination, we precisely excised the IR, thus generating plants with a substantially reduced plastid genome size. We show that the lack of the IR results in a mildly reduced plastid ribosome number, suggesting a gene dosage benefit from the duplicated presence of the ribosomal RNA operon. Moreover, the IR deletion plants contain an increased number of plastid genomes, suggesting that genome copy number is regulated by measuring total plastid DNA content rather than by counting genomes. Together, our findings (1) demonstrate that the IR can enhance the translation capacity of the plastid, (2) reveal the relationship between genome size and genome copy number, and (3) provide a simplified plastid genome structure that will facilitate future synthetic biology applications.
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Affiliation(s)
- Carolin Krämer
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Christian R Boehm
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Jinghan Liu
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | | | - Alexander P Hertle
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Joachim Forner
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Stephanie Ruf
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Mark A Schöttler
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Reimo Zoschke
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany.
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Li QQ, Zhang ZP, Aogan, Wen J. Comparative chloroplast genomes of Argentina species: genome evolution and phylogenomic implications. FRONTIERS IN PLANT SCIENCE 2024; 15:1349358. [PMID: 38766467 PMCID: PMC11099909 DOI: 10.3389/fpls.2024.1349358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 03/25/2024] [Indexed: 05/22/2024]
Abstract
The genus Argentina Hill belongs to the tribe Potentilleae Sweet and contains approximately 75 species predominantly distributed in the Sino-Himalayan region and the Malesian archipelago. So far we have less knowledge on the phylogenetic relationships within Argentina owing to limited sampling of Argentina taxa or gene fragments in previous studies. Moreover, to date there is no phylogenetic study on Argentina from the perspective of comparative chloroplast (cp) genomics. Here we performed comparative genomic analyses on the cp genomes of 39 accessions representing 18 taxa of Argentina. The Argentina cp genomes presented the typical quadripartite structure, with the sizes ranging from 155 096 bp to 157 166 bp. The 39 Argentina cp genomes contained a set of 112 unique genes, comprising four ribosomal RNA (rRNA) genes, 30 transfer RNA (tRNA) genes, as well as 78 protein-coding genes (PCGs). The cp genome organization, gene content and order in Argentina were highly conserved, but some visible divergences were present in IR/SC boundary regions. Ten regions (trnH-GUG-psbA, trnG-GCC-trnfM-CAU, trnD-GUC-trnY-GUA, rpl32-trnL-UAG, atpH-atpI, rps16-trnQ-UUG, trnS-GCU-trnG-UCC, ndhF-rpl32, trnR-UCU-atpA, and accD-psaI) were identified as excellent candidate DNA markers for future studies on species identification, population genetics and phylogeny of Argentina. Our results indicated that Argentina is monophyletic. In the current sampling, the A. smithiana - A. anserina clade was sister to the remainder of Argentina. Our results corroborated the previous taxonomic treatments to transfer A. phanerophlebia and A. micropetala from the genus Sibbaldia L. to Argentina. Our results showed close relationships among A. stenophylla, A. microphylla, A. taliensis, and A. tatsienluensis, congruent with previous studies based on the morphology of these species. Twenty-six genes (rps3, rps15, rps16, rps19, rpl16, rpl20, rpl22, rpoA, rpoB, rpoC1, rpoC2, atpA, atpF, psbB, psbF, ndhA, ndhB, ndhC, ndhD, ndhF, rbcL, accD, ccsA, matK, ycf1, ycf2) were with sites under positive selection, and adaptive evolution of these genes might have played crucial roles in Argentina species adaptation to the harsh mountain environment. This study will facilitate future work on taxonomy, phylogenetics, and adaptive evolution of Argentina.
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Affiliation(s)
- Qin-Qin Li
- College of Life Science and Technology, Inner Mongolia Normal University, Hohhot, China
- Key Laboratory of Biodiversity Conservation and Sustainable Utilization in Mongolian Plateau for College and University of Inner Mongolia Autonomous Region, Hohhot, China
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC, United States
| | - Zhi-Ping Zhang
- College of Computer Science and Technology, Inner Mongolia Normal University, Hohhot, China
| | - Aogan
- College of Life Science and Technology, Inner Mongolia Normal University, Hohhot, China
| | - Jun Wen
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC, United States
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3
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Li Q, Du J, Qiao Z, Pan C, He W, Zhang L, Li X, Nie Y, Li X, Pan G, Zhang Z, Li G, Ding H. White and green striate leaves 1, predicted to encode a 16S rRNA processing protein, plays a critical role in the processing of chloroplast ribosomes in maize ( Zea mays L.). MOLECULAR BREEDING : NEW STRATEGIES IN PLANT IMPROVEMENT 2023; 43:65. [PMID: 37538809 PMCID: PMC10393919 DOI: 10.1007/s11032-023-01407-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 07/11/2023] [Indexed: 08/05/2023]
Abstract
Ribosomes play a crucial role in protein biosynthesis and are linked to plant growth and development. The RimM protein has been shown to be involved in the maturation of 30S ribosomal subunits, but its exact function in plants is still unknown. In this study, we discovered a maize mutant with white and green striate leaves (wgsl1) and reduced chlorophyll content. Genetic analysis showed that the wgsl1 mutation was recessive and controlled by a single nuclear gene. Map-based cloning of ZmWGSL1 identified a base substitution (G to A) that generated a missense mutation within the Zm00001d039036 gene in the wgsl1 mutant. Zm00001d039036 encodes a 16S rRNA processing protein containing the RimM motif. Further analysis of transcriptomic data showed that the transcript levels of many ribosomal proteins involved in the small and big ribosomal subunits were dramatically up-regulated in the wgsl1 mutant. Moreover, the level of ribosomal multimers was decreased. This suggests that ZmWGSL1 plays a crucial role in the maturation of the ribosome, leading to abnormal plant growth and development. In addition, subcellular localization results indicate that WGSL1 is localized in chloroplasts. Therefore, we suggest that WGSL1 is a nuclear-encoded protein, is transported to the chloroplast to drive functions, and affects the processing of ribosomes in the chloroplast. Supplementary Information The online version contains supplementary material available at 10.1007/s11032-023-01407-y.
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Affiliation(s)
- Qigui Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, 271018 Shangdong Province China
| | - Jiyuan Du
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, 271018 Shangdong Province China
| | - Zhenghao Qiao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, 271018 Shangdong Province China
| | - Chao Pan
- Maize Research Institute, Sichuan Agricultural University, Chengdu, 611130 China
| | - Weiqiang He
- Maize Research Institute, Sichuan Agricultural University, Chengdu, 611130 China
| | - Li Zhang
- Maize Research Institute, Sichuan Agricultural University, Chengdu, 611130 China
| | - Xiaohu Li
- Maize Research Institute, Sichuan Agricultural University, Chengdu, 611130 China
| | - Yongxin Nie
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, 271018 Shangdong Province China
| | - Xinzheng Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, 271018 Shangdong Province China
| | - Guangtang Pan
- Maize Research Institute, Sichuan Agricultural University, Chengdu, 611130 China
| | - Zhiming Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, 271018 Shangdong Province China
| | - Gaoke Li
- Crops Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Provincial Key Laboratory of Crop Genetic Improvement, Guangzhou, 510640 Guangdong Province China
| | - Haiping Ding
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, 271018 Shangdong Province China
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Chabi M, Goulas E, Galinousky D, Blervacq AS, Lucau-Danila A, Neutelings G, Grec S, Day A, Chabbert B, Haag K, Müssig J, Arribat S, Planchon S, Renaut J, Hawkins S. Identification of new potential molecular actors related to fiber quality in flax through Omics. FRONTIERS IN PLANT SCIENCE 2023; 14:1204016. [PMID: 37528984 PMCID: PMC10390313 DOI: 10.3389/fpls.2023.1204016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 06/20/2023] [Indexed: 08/03/2023]
Abstract
One of the biggest challenges for a more widespread utilization of plant fibers is to better understand the different molecular factors underlying the variability in fineness and mechanical properties of both elementary and scutched fibers. Accordingly, we analyzed genome-wide transcription profiling from bast fiber bearing tissues of seven different flax varieties (4 spring, 2 winter fiber varieties and 1 winter linseed) and identified 1041 differentially expressed genes between varieties, of which 97 were related to cell wall metabolism. KEGG analysis highlighted a number of different enriched pathways. Subsequent statistical analysis using Partial Least-Squares Discriminant Analysis showed that 73% of the total variance was explained by the first 3 X-variates corresponding to 56 differentially expressed genes. Calculation of Pearson correlations identified 5 genes showing a strong correlation between expression and morphometric data. Two-dimensional gel proteomic analysis on the two varieties showing the most discriminant and significant differences in morphometrics revealed 1490 protein spots of which 108 showed significant differential abundance. Mass spectrometry analysis successfully identified 46 proteins representing 32 non-redundant proteins. Statistical clusterization based on the expression level of genes corresponding to the 32 proteins showed clear discrimination into three separate clusters, reflecting the variety type (spring-/winter-fiber/oil). Four of the 32 proteins were also highly correlated with morphometric features. Examination of predicted functions for the 9 (5 + 4) identified genes highlighted lipid metabolism and senescence process. Calculation of Pearson correlation coefficients between expression data and retted fiber mechanical measurements (strength and maximum force) identified 3 significantly correlated genes. The genes were predicted to be connected to cell wall dynamics, either directly (Expansin-like protein), or indirectly (NAD(P)-binding Rossmann-fold superfamily protein). Taken together, our results have allowed the identification of molecular actors potentially associated with the determination of both in-planta fiber morphometrics, as well as ex-planta fiber mechanical properties, both of which are key parameters for elementary fiber and scutched fiber quality in flax.
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Affiliation(s)
- Malika Chabi
- Université de Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Estelle Goulas
- Université de Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Dmitry Galinousky
- Université de Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Anne-Sophie Blervacq
- Université de Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Anca Lucau-Danila
- Université de Lille, UMRT 1158 BioEcoAgro, Institut Charles Viollette, Lille, France
| | - Godfrey Neutelings
- Université de Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Sébastien Grec
- Université de Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Arnaud Day
- Université de Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
- Fibres Recherche Développement, Technopole de l’Aube en Champagne – Hôtel de Bureaux 2, 2 rue Gustave Eiffel, CS 90601, Troyes, France
| | - Brigitte Chabbert
- Université de Reims Champagne-Ardenne, INRAE, FARE, UMR A 614, Reims, France
| | - Katharina Haag
- Fraunhofer-Institute for Manufacturing Technology and Advanced Materials IFAM, Bremen, Germany
| | - Jörg Müssig
- The Biological Materials Group, HSB – City University of Applied Sciences, Bremen, Germany
| | - Sandrine Arribat
- Université de Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Sébastien Planchon
- Department of Environmental Research and Innovation, Luxembourg Institute of Science and Technology, Esch-sur-Alzette, Luxembourg
| | - Jenny Renaut
- Department of Environmental Research and Innovation, Luxembourg Institute of Science and Technology, Esch-sur-Alzette, Luxembourg
| | - Simon Hawkins
- Université de Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
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5
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Postel Z, Mauri T, Lensink MF, Touzet P. What is the potential impact of genetic divergence of plastid ribosomal genes between Silene nutans lineages in hybrids? An in silico approach using the 3D structure of the plastid ribosome. FRONTIERS IN PLANT SCIENCE 2023; 14:1167478. [PMID: 37223795 PMCID: PMC10201985 DOI: 10.3389/fpls.2023.1167478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 03/31/2023] [Indexed: 05/25/2023]
Abstract
Introduction Following the integration of cyanobacteria into the eukaryotic cells, many genes were transferred from the plastid to the nucleus. As a result, plastid complexes are encoded both by plastid and nuclear genes. Tight co-adaptation is required between these genes as plastid and nuclear genomes differ in several characteristics, such as mutation rate and inheritance patterns. Among these are complexes from the plastid ribosome, composed of two main subunits: a large and a small one, both composed of nuclear and plastid gene products. This complex has been identified as a potential candidate for sheltering plastid-nuclear incompatibilities in a Caryophyllaceae species, Silene nutans. This species is composed of four genetically differentiated lineages, which exhibit hybrid breakdown when interlineage crosses are conducted. As this complex is composed of numerous interacting plastid-nuclear gene pairs, in the present study, the goal was to reduce the number of gene pairs that could induce such incompatibilities. Method We used the previously published 3D structure of the spinach ribosome to further elucidate which of the potential gene pairs might disrupt plastid-nuclear interactions within this complex. After modeling the impact of the identified mutations on the 3D structure, we further focused on one strongly mutated plastid-nuclear gene pair: rps11-rps21. We used the centrality measure of the mutated residues to further understand if the modified interactions and associated modified centralities might be correlated with hybrid breakdown. Results and discussion This study highlights that lineage-specific mutations in essential plastid and nuclear genes might disrupt plastid-nuclear protein interactions of the plastid ribosome and that reproductive isolation correlates with changes in residue centrality values. Because of this, the plastid ribosome might be involved in hybrid breakdown in this system.
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Affiliation(s)
- Zoé Postel
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, Lille, France
| | - Théo Mauri
- Univ. Lille, CNRS, UMR 8576 – UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Marc F. Lensink
- Univ. Lille, CNRS, UMR 8576 – UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Pascal Touzet
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, Lille, France
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Liu K, Lee KP, Duan J, Kim EY, Singh RM, Di M, Meng Z, Kim C. Cooperative role of AtRsmD and AtRimM proteins in modification and maturation of 16S rRNA in plastids. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 114:310-324. [PMID: 36752655 DOI: 10.1111/tpj.16135] [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: 08/12/2022] [Accepted: 02/01/2023] [Indexed: 05/10/2023]
Abstract
Chloroplast pre-ribosomal RNA (rRNA) undergoes maturation, which is critical for ribosome assembly. While the central and auxiliary factors in rRNA maturation have been elucidated in bacteria, their mode of action remains largely unexplored in chloroplasts. We now reveal chloroplast-specific factors involved in 16S rRNA maturation, Arabidopsis thaliana orthologs of bacterial RsmD methyltransferase (AtRsmD) and ribosome maturation factor RimM (AtRimM). A forward genetic screen aimed to find suppressors of the Arabidopsis yellow variegated 2 (var2) mutant defective in photosystem II quality control found a causal nonsense mutation in AtRsmD. The substantially impaired 16S rRNA maturation and translation due to the mutation rescued the leaf variegation phenotype by lowering the levels of chloroplast-encoded proteins, including photosystem II core proteins, in var2. The subsequent co-immunoprecipitation coupled with mass spectrometry analyses and bimolecular fluorescence complementation assay found that AtRsmD interacts with AtRimM. Consistent with their interaction, loss of AtRimM also considerably impairs 16S rRNA maturation with decelerated m2 G915 modification in 16S rRNA catalyzed by AtRsmD. The atrimM mutation also rescued var2 mutant phenotypes, corroborating the functional interplay between AtRsmD and AtRimM towards modification and maturation of 16S rRNA and chloroplast proteostasis. The maturation and post-transcriptional modifications of rRNA are critical to assembling ribosomes responsible for protein translation. Here, we revealed that the cooperative regulation of 16S rRNA m2 G915 modifications by AtRsmD methyltransferase and ribosome assembly factor AtRimM contributes to 16S rRNA maturation, ribosome assembly, and proteostasis in chloroplasts.
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Affiliation(s)
- Kaiwei Liu
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Keun Pyo Lee
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Jianli Duan
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Eun Yu Kim
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Chinese Academy of Sciences, Shanghai, 200032, China
| | - Rahul Mohan Singh
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Minghui Di
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhuoling Meng
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Chanhong Kim
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
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7
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Chen H, Wang Q, Fan M, Zhang X, Feng P, Zhu L, Wu J, Cheng X, Wang J. A Single Nucleotide Variation of CRS2 Affected the Establishment of Photosynthetic System in Rice. Int J Mol Sci 2023; 24:ijms24065796. [PMID: 36982870 PMCID: PMC10054620 DOI: 10.3390/ijms24065796] [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: 02/21/2023] [Revised: 03/11/2023] [Accepted: 03/15/2023] [Indexed: 03/22/2023] Open
Abstract
Chloroplasts are essential sites for plant photosynthesis, and the biogenesis of the photosynthetic complexes involves the interaction of nuclear genes and chloroplast genes. In this study, we identified a rice pale green leaf mutant, crs2. The crs2 mutant showed different degrees of low chlorophyll phenotypes at different growth stages, especially at the seedling stage. Fine mapping and DNA sequencing of crs2 revealed a single nucleotide substitution (G4120A) in the eighth exons of CRS2, causing a G-to-R mutation of the 229th amino acid of CRS2 (G229R). The results of complementation experiments confirmed that this single-base mutation in crs2 is responsible for the phenotype of the crs2 mutant. CRS2 encodes a chloroplast RNA splicing 2 protein localized in the chloroplast. Western blot results revealed an abnormality in the abundance of the photosynthesis-related protein in crs2. However, the mutation of CRS2 leads to the enhancement of antioxidant enzyme activity, which could reduce ROS levels. Meanwhile, with the release of Rubisco activity, the photosynthetic performance of crs2 was improved. In summary, the G229R mutation in CRS2 causes chloroplast protein abnormalities and affects photosystem performance in rice; the above findings facilitate the elucidation of the physiological mechanism of chloroplast proteins affecting photosynthesis.
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Affiliation(s)
- Hongwei Chen
- Key Laboratory of Rice Biology & Genetic Breeding in Northeast China, Ministry of Agriculture and Rural Areas, Rice Research Institute, Shenyang Agricultural University, Shenyang 110866, China
| | - Qi Wang
- Key Laboratory of Rice Biology & Genetic Breeding in Northeast China, Ministry of Agriculture and Rural Areas, Rice Research Institute, Shenyang Agricultural University, Shenyang 110866, China
| | - Mingqian Fan
- Key Laboratory of Rice Biology & Genetic Breeding in Northeast China, Ministry of Agriculture and Rural Areas, Rice Research Institute, Shenyang Agricultural University, Shenyang 110866, China
| | - Xijuan Zhang
- Cultivation and Tillage Institute, Heilongjiang Academy of Agricultural Sciences, Heilongjiang Provincial Engineering Technology Research Center of Crop Cold Damage, Harbin 150086, China
| | - Pulin Feng
- Key Laboratory of Rice Biology & Genetic Breeding in Northeast China, Ministry of Agriculture and Rural Areas, Rice Research Institute, Shenyang Agricultural University, Shenyang 110866, China
| | - Lin Zhu
- Key Laboratory of Rice Biology & Genetic Breeding in Northeast China, Ministry of Agriculture and Rural Areas, Rice Research Institute, Shenyang Agricultural University, Shenyang 110866, China
| | - Jiayi Wu
- Key Laboratory of Rice Biology & Genetic Breeding in Northeast China, Ministry of Agriculture and Rural Areas, Rice Research Institute, Shenyang Agricultural University, Shenyang 110866, China
| | - Xiaoyi Cheng
- Key Laboratory of Rice Biology & Genetic Breeding in Northeast China, Ministry of Agriculture and Rural Areas, Rice Research Institute, Shenyang Agricultural University, Shenyang 110866, China
- Correspondence: (X.C.); or (J.W.)
| | - Jiayu Wang
- Key Laboratory of Rice Biology & Genetic Breeding in Northeast China, Ministry of Agriculture and Rural Areas, Rice Research Institute, Shenyang Agricultural University, Shenyang 110866, China
- Correspondence: (X.C.); or (J.W.)
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8
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Robles P, Quesada V. Unveiling the functions of plastid ribosomal proteins in plant development and abiotic stress tolerance. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 189:35-45. [PMID: 36041366 DOI: 10.1016/j.plaphy.2022.07.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 07/22/2022] [Accepted: 07/24/2022] [Indexed: 06/15/2023]
Abstract
Translation of mRNAs into proteins is a universal process and ribosomes are the molecular machinery that carries it out. In eukaryotic cells, ribosomes can be found in the cytoplasm, mitochondria, and also in the chloroplasts of photosynthetic organisms. A number of genetic studies have been performed to determine the function of plastid ribosomal proteins (PRPs). Tobacco has been frequently used as a system to study the ribosomal proteins encoded by the chloroplast genome. In contrast, Arabidopsis thaliana and rice are preferentially used models to study the function of nuclear-encoded PRPs by using direct or reverse genetics approaches. The results of these works have provided a relatively comprehensive catalogue of the roles of PRPs in different plant biology aspects, which highlight that some PRPs are essential, while others are not. The latter ones are involved in chloroplast biogenesis, lateral root formation, leaf morphogenesis, plant growth, photosynthesis or chlorophyll synthesis. Furthermore, small gene families encode some PRPs. In the last few years, an increasing number of findings have revealed a close association between PRPs and tolerance to adverse environmental conditions. Sometimes, the same PRP can be involved in both developmental processes and the response to abiotic stress. The aim of this review is to compile and update the findings hitherto published on the functional analysis of PRPs. The study of the phenotypic effects caused by the disruption of PRPs from different species reveals the involvement of PRPs in different biological processes and highlights the significant impact of plastid translation on plant biology.
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Affiliation(s)
- Pedro Robles
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202, Elche, Spain
| | - Víctor Quesada
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202, Elche, Spain.
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9
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Chen S, Zeng X, Li Y, Qiu S, Peng X, Xie X, Liu Y, Liao C, Tang X, Wu J. The nuclear-encoded plastid ribosomal protein L18s are essential for plant development. FRONTIERS IN PLANT SCIENCE 2022; 13:949897. [PMID: 36212366 PMCID: PMC9538462 DOI: 10.3389/fpls.2022.949897] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 08/29/2022] [Indexed: 06/16/2023]
Abstract
Plastid ribosomal proteins (PRPs) are necessary components for plastid ribosome biogenesis, playing essential roles in plastid development. The ribosomal protein L18 involved in the assemble of 5S rRNA and 23S rRNA, is vital for E. coli viability, but the functions of its homologs in plant plastid remain elusive. Here, we characterized the functions of the plant plastid ribosomal protein L18s (PRPL18s) in Arabidopsis and rice. AtPRPL18 was ubiquitously expressed in most of the plant tissues, but with higher expression levels in seedling shoots, leaves, and flowers. AtPRPL18 was localized in chloroplast. Genetic and cytological analyses revealed that a loss of function of AtPRPL18 resulted in embryo development arrest at globular stage. However, overexpression of AtPRPL18 did not show any visible phenotypical changes in Arabidopsis. The rice OsPRPL18 was localized in chloroplast. In contrast to AtPRPL18, knockout of OsPRPL18 did not affect embryo development, but led to an albino lethal phenotype at the seedling stage. Cytological analyses showed that chloroplast development was impaired in the osprpl18-1 mutant. Moreover, a loss-function of OsPRPL18 led to defects in plastid ribosome biogenesis and a serious reduction in the efficiency of plastid intron splicing. In all, these results suggested that PRPL18s play critical roles in plastid ribosome biogenesis, plastid intron splicing, and chloroplast development, and are essential for plant survival.
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Affiliation(s)
- Shujing Chen
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Xinhuang Zeng
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Yiqi Li
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Shijun Qiu
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Xiaoqun Peng
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Xinjue Xie
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Yujie Liu
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Chancan Liao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Xiaoyan Tang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong, China
- Shenzhen Institute of Molecular Crop Design, Shenzhen, China
| | - Jianxin Wu
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
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10
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Dupouy G, McDermott E, Cashell R, Scian A, McHale M, Ryder P, de Groot J, Lucca N, Brychkova G, McKeown PC, Spillane C. Plastid ribosome protein L5 is essential for post-globular embryo development in Arabidopsis thaliana. PLANT REPRODUCTION 2022; 35:189-204. [PMID: 35247095 PMCID: PMC9352626 DOI: 10.1007/s00497-022-00440-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 02/14/2022] [Indexed: 06/14/2023]
Abstract
Plastid ribosomal proteins (PRPs) can play essential roles in plastid ribosome functioning that affect plant function and development. However, the roles of many PRPs remain unknown, including elucidation of which PRPs are essential or display redundancy. Here, we report that the nuclear-encoded PLASTID RIBOSOMAL PROTEIN L5 (PRPL5) is essential for early embryo development in A. thaliana, as homozygous loss-of-function mutations in the PRPL5 gene impairs chloroplast development and leads to embryo failure to develop past the globular stage. We confirmed the prpl5 embryo-lethal phenotype by generating a mutant CRISPR/Cas9 line and by genetic complementation. As PRPL5 underwent transfer to the nuclear genome early in the evolution of Embryophyta, PRPL5 can be expected to have acquired a chloroplast transit peptide. We identify and validate the presence of an N-terminal chloroplast transit peptide, but unexpectedly also confirm the presence of a conserved and functional Nuclear Localization Signal on the protein C-terminal end. This study highlights the fundamental role of the plastid translation machinery during the early stages of embryo development in plants and raises the possibility of additional roles of plastid ribosomal proteins in the nucleus.
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Affiliation(s)
- Gilles Dupouy
- Genetics and Biotechnology Lab, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, Aras de Brun, National University of Ireland Galway, University Road, Galway, H91 REW4, Ireland
| | - Emma McDermott
- Genetics and Biotechnology Lab, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, Aras de Brun, National University of Ireland Galway, University Road, Galway, H91 REW4, Ireland
| | - Ronan Cashell
- Genetics and Biotechnology Lab, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, Aras de Brun, National University of Ireland Galway, University Road, Galway, H91 REW4, Ireland
| | - Anna Scian
- Genetics and Biotechnology Lab, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, Aras de Brun, National University of Ireland Galway, University Road, Galway, H91 REW4, Ireland
| | - Marcus McHale
- Genetics and Biotechnology Lab, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, Aras de Brun, National University of Ireland Galway, University Road, Galway, H91 REW4, Ireland
| | - Peter Ryder
- Genetics and Biotechnology Lab, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, Aras de Brun, National University of Ireland Galway, University Road, Galway, H91 REW4, Ireland
| | - Joelle de Groot
- Genetics and Biotechnology Lab, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, Aras de Brun, National University of Ireland Galway, University Road, Galway, H91 REW4, Ireland
| | - Noel Lucca
- Genetics and Biotechnology Lab, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, Aras de Brun, National University of Ireland Galway, University Road, Galway, H91 REW4, Ireland
| | - Galina Brychkova
- Genetics and Biotechnology Lab, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, Aras de Brun, National University of Ireland Galway, University Road, Galway, H91 REW4, Ireland
| | - Peter C McKeown
- Genetics and Biotechnology Lab, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, Aras de Brun, National University of Ireland Galway, University Road, Galway, H91 REW4, Ireland
| | - Charles Spillane
- Genetics and Biotechnology Lab, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, Aras de Brun, National University of Ireland Galway, University Road, Galway, H91 REW4, Ireland.
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11
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Chen W, Huang J, Chen S, Zhang L, Rochaix JD, Peng L, Xin Q. Stromal Protein Chloroplast Development and Biogenesis1 Is Essential for Chloroplast Development and Biogenesis in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2022; 13:815859. [PMID: 35222475 PMCID: PMC8866770 DOI: 10.3389/fpls.2022.815859] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 01/17/2022] [Indexed: 06/14/2023]
Abstract
Although numerous studies have been carried out on chloroplast development and biogenesis, the underlying regulatory mechanisms are still largely elusive. Here, we characterized a chloroplast stromal protein Chloroplast Development and Biogenesis1 (CDB1). The knockout cdb1 mutant exhibits a seedling-lethal and ivory leaf phenotype. Immunoblot and RNA blot analyses show that accumulation of chloroplast ribosomes is compromised in cdb1, resulting in an almost complete loss of plastid-encoded proteins including the core subunits of the plastid-encoded RNA polymerase (PEP) RpoB and RpoC2, and therefore in impaired PEP activity. Orthologs of CDB1 are found in green algae and land plants. Moreover, a protein shows high similarity with CDB1, designated as CDB1-Like (CDB1L), is present in angiosperms. Absence of CDB1L results in impaired embryo development. While CDB1 is specifically located in the chloroplast stroma, CDB1L is localized in both chloroplasts and mitochondria in Arabidopsis. Thus, our results demonstrate that CDB1 is indispensable for chloroplast development and biogenesis through its involvement in chloroplast ribosome assembly whereas CDB1L may fulfill a similar function in both mitochondria and chloroplasts.
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Affiliation(s)
- Weijie Chen
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Jingang Huang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Shiwei Chen
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Lin Zhang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Jean-David Rochaix
- Departments of Molecular Biology and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Lianwei Peng
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Qiang Xin
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
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12
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Postel Z, Poux C, Gallina S, Varré JS, Godé C, Schmitt E, Meyer E, Van Rossum F, Touzet P. Reproductive isolation among lineages of Silene nutans (Caryophyllaceae): A potential involvement of plastid-nuclear incompatibilities. Mol Phylogenet Evol 2022; 169:107436. [DOI: 10.1016/j.ympev.2022.107436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 01/28/2022] [Accepted: 02/02/2022] [Indexed: 11/26/2022]
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13
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Tang X, Shi F, Wang Y, Huang S, Zhao Y, Feng H. Proteomic analysis of a plastid gene encoding RPS4 mutant in Chinese cabbage (Brassica campestris L. ssp. pekinensis). Funct Integr Genomics 2021; 22:113-130. [PMID: 34881421 DOI: 10.1007/s10142-021-00808-6] [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: 12/04/2020] [Revised: 02/20/2021] [Accepted: 09/18/2021] [Indexed: 10/19/2022]
Abstract
Plastids are important plant cell organelles containing a genome and bacterial-type 70S ribosomes-primarily composed of plastid ribosomal proteins and ribosomal RNAs. In this study, a chlorophyll-deficient mutant (cdm) obtained from double-haploid Chinese cabbage 'FT' was identified as a plastome mutant with an A-to-C base substitution in the plastid gene encoding the ribosomal protein RPS4. To further elucidate the function and regulatory mechanisms of RPS4, a comparative proteomic analysis was conducted between cdm and its wild-type 'FT' plants by isobaric tags and a relative and absolute quantitation (iTRAQ)-based strategy. A total of 6,245 proteins were identified, 540 of which were differentially abundant proteins (DAPs) in the leaves of cdm as compared to those of 'FT'-including 233 upregulated and 307 downregulated proteins. Upregulated DAPs were mainly involved in translation, organonitrogen compound biosynthetic process, ribosomes, and spliceosomes. Meanwhile, downregulated DAPs were mainly involved in photosynthesis, photosynthetic reaction centres, photosynthetic light harvesting, carbon fixation, and chlorophyll binding. These results indicated an important role of RPS4 in the regulation of growth and development of Chinese cabbage, possibly by regulating plastid translation activity by affecting the expression of specific photosynthesis- and cold stress-related proteins. Moreover, a multiple reaction monitoring (MRM) test and quantitative real-time polymerase chain reaction analysis confirmed our iTRAQ results. Quantitative proteomic analysis allowed us to confirm diverse changes in the metabolic pathways between cdm and 'FT' plants. This work provides new insights into the regulation of chlorophyll biosynthesis and photosynthesis in Chinese cabbage.
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Affiliation(s)
- Xiaoyan Tang
- Department of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenhe District, Shenyang, 110866, China.,Anhui Provincial Engineering Laboratory of Horticultural Crop Breeding College of Horticulture, Anhui Agricultural University, 130 Changjiang West Road, Shushan District, Hefei, China
| | - Fengyan Shi
- Department of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenhe District, Shenyang, 110866, China
| | - Yiheng Wang
- Biotechnology Research Institute, Xiqing District, Tianjin Academy of Agricultural Sciences, Jinjing Road 17 km, Tianjin, 300384, China
| | - Shengnan Huang
- Department of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenhe District, Shenyang, 110866, China
| | - Ying Zhao
- Department of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenhe District, Shenyang, 110866, China
| | - Hui Feng
- Department of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenhe District, Shenyang, 110866, China.
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14
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Li M, Ruwe H, Melzer M, Junker A, Hensel G, Tschiersch H, Schwenkert S, Chamas S, Schmitz-Linneweber C, Börner T, Stein N. The Arabidopsis AAC Proteins CIL and CIA2 Are Sub-functionalized Paralogs Involved in Chloroplast Development. FRONTIERS IN PLANT SCIENCE 2021; 12:681375. [PMID: 34163512 PMCID: PMC8215611 DOI: 10.3389/fpls.2021.681375] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 05/06/2021] [Indexed: 05/22/2023]
Abstract
The Arabidopsis gene Chloroplast Import Apparatus 2 (CIA2) encodes a transcription factor that positively affects the activity of nuclear genes for chloroplast ribosomal proteins and chloroplast protein import machineries. CIA2-like (CIL) is the paralogous gene of CIA2. We generated a cil mutant by site-directed mutagenesis and compared it with cia2 and cia2cil double mutant. Phenotype of the cil mutant did not differ from the wild type under our growth conditions, except faster growth and earlier time to flowering. Compared to cia2, the cia2cil mutant showed more impaired chloroplast functions and reduced amounts of plastid ribosomal RNAs. In silico analyses predict for CIA2 and CIL a C-terminal CCT domain and an N-terminal chloroplast transit peptide (cTP). Chloroplast (and potentially nuclear) localization was previously shown for HvCMF3 and HvCMF7, the homologs of CIA2 and CIL in barley. We observed nuclear localization of CIL after transient expression in Arabidopsis protoplasts. Surprisingly, transformation of cia2 with HvCMF3, HvCMF7, or with a truncated CIA2 lacking the predicted cTP could partially rescue the pale-green phenotype of cia2. These data are discussed with respect to potentially overlapping functions between CIA2, CIL, and their barley homologs and to the function of the putative cTPs of CIA2 and CIL.
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Affiliation(s)
- Mingjiu Li
- Genomics of Genetic Resources, Department of Genebank, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Hannes Ruwe
- Molecular Genetics, Institute of Biology, Humboldt University, Rhoda Erdmann Haus, Berlin, Germany
| | - Michael Melzer
- Structural Cell Biology, Department of Physiology and Cell Biology, IPK, Gatersleben, Germany
| | - Astrid Junker
- Acclimation Dynamics and Phenotyping, Department of Molecular Genetics, IPK, Gatersleben, Germany
| | - Goetz Hensel
- Plant Reproductive Biology, Department of Physiology and Cell Biology, IPK, Gatersleben, Germany
| | - Henning Tschiersch
- Acclimation Dynamics and Phenotyping, Department of Molecular Genetics, IPK, Gatersleben, Germany
| | - Serena Schwenkert
- Department of Biology I, Ludwig-Maximilians University of Munich, Munich, Germany
| | - Sindy Chamas
- Plant Reproductive Biology, Department of Physiology and Cell Biology, IPK, Gatersleben, Germany
| | | | - Thomas Börner
- Molecular Genetics, Institute of Biology, Humboldt University, Rhoda Erdmann Haus, Berlin, Germany
| | - Nils Stein
- Genomics of Genetic Resources, Department of Genebank, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
- Department of Crop Sciences, Center for Integrated Breeding Research (CiBreed), Georg-August-Universität Göttingen, Göttingen, Germany
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15
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Forsythe ES, Williams AM, Sloan DB. Genome-wide signatures of plastid-nuclear coevolution point to repeated perturbations of plastid proteostasis systems across angiosperms. THE PLANT CELL 2021; 33:980-997. [PMID: 33764472 PMCID: PMC8226287 DOI: 10.1093/plcell/koab021] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/16/2021] [Indexed: 05/05/2023]
Abstract
Nuclear and plastid (chloroplast) genomes experience different mutation rates, levels of selection, and transmission modes, yet key cellular functions depend on their coordinated interactions. Functionally related proteins often show correlated changes in rates of sequence evolution across a phylogeny [evolutionary rate covariation (ERC)], offering a means to detect previously unidentified suites of coevolving and cofunctional genes. We performed phylogenomic analyses across angiosperm diversity, scanning the nuclear genome for genes that exhibit ERC with plastid genes. As expected, the strongest hits were highly enriched for genes encoding plastid-targeted proteins, providing evidence that cytonuclear interactions affect rates of molecular evolution at genome-wide scales. Many identified nuclear genes functioned in post-transcriptional regulation and the maintenance of protein homeostasis (proteostasis), including protein translation (in both the plastid and cytosol), import, quality control, and turnover. We also identified nuclear genes that exhibit strong signatures of coevolution with the plastid genome, but their encoded proteins lack organellar-targeting annotations, making them candidates for having previously undescribed roles in plastids. In sum, our genome-wide analyses reveal that plastid-nuclear coevolution extends beyond the intimate molecular interactions within chloroplast enzyme complexes and may be driven by frequent rewiring of the machinery responsible for maintenance of plastid proteostasis in angiosperms.
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Affiliation(s)
- Evan S Forsythe
- Department of Biology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Alissa M Williams
- Department of Biology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, Colorado 80523, USA
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16
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Caroca R, Howell KA, Malinova I, Burgos A, Tiller N, Pellizzer T, Annunziata MG, Hasse C, Ruf S, Karcher D, Bock R. Knockdown of the plastid-encoded acetyl-CoA carboxylase gene uncovers functions in metabolism and development. PLANT PHYSIOLOGY 2021; 185:1091-1110. [PMID: 33793919 PMCID: PMC8133629 DOI: 10.1093/plphys/kiaa106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 12/11/2020] [Indexed: 06/12/2023]
Abstract
De novo fatty acid biosynthesis in plants relies on a prokaryotic-type acetyl-CoA carboxylase (ACCase) that resides in the plastid compartment. The enzyme is composed of four subunits, one of which is encoded in the plastid genome, whereas the other three subunits are encoded by nuclear genes. The plastid gene (accD) encodes the β-carboxyltransferase subunit of ACCase and is essential for cell viability. To facilitate the functional analysis of accD, we pursued a transplastomic knockdown strategy in tobacco (Nicotiana tabacum). By introducing point mutations into the translational start codon of accD, we obtained stable transplastomic lines with altered ACCase activity. Replacement of the standard initiator codon AUG with UUG strongly reduced AccD expression, whereas replacement with GUG had no detectable effects. AccD knockdown mutants displayed reduced ACCase activity, which resulted in changes in the levels of many but not all species of cellular lipids. Limiting fatty acid availability caused a wide range of macroscopic, microscopic, and biochemical phenotypes, including impaired chloroplast division, reduced seed set, and altered storage metabolism. Finally, while the mutants displayed reduced growth under photoautotrophic conditions, they showed exaggerated growth under heterotrophic conditions, thus uncovering an unexpected antagonistic role of AccD activity in autotrophic and heterotrophic growth.
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Affiliation(s)
- Rodrigo Caroca
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Katharine A Howell
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Irina Malinova
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Asdrúbal Burgos
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Nadine Tiller
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Tommaso Pellizzer
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | | | - Claudia Hasse
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Stephanie Ruf
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Daniel Karcher
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
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17
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Escobar-Tovar L, Sierra J, Hernández-Muñoz A, McQuinn RP, Mathioni S, Cordoba E, Colas des Francs-Small C, Meyers BC, Pogson B, León P. Deconvoluting apocarotenoid-mediated retrograde signaling networks regulating plastid translation and leaf development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 105:1582-1599. [PMID: 33340183 DOI: 10.1111/tpj.15134] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 11/30/2020] [Indexed: 06/12/2023]
Abstract
Signals originating within plastids modulate organelle differentiation by transcriptionally regulating nuclear-encoded genes. These retrograde signals are also integral regulators of plant development, including leaf morphology. The clb5 mutant displays severe leaf morphology defects due to Apocarotenoid Signal 1 (ACS1) accumulation in the developmentally arrested plastid. Transcriptomic analysis of clb5 validates that ACS1 accumulation deregulates hundreds of nuclear genes, including the suppression of most genes encoding plastid ribosomal proteins. Herein, we order the molecular events causing the leaf phenotype associated with the accumulation of ACS1, which includes two consecutive retrograde signaling cascades. Firstly, ACS1 originating in the plastid drives inhibition of plastid translation (IPT) via nuclear transcriptome remodeling of chlororibosomal proteins, requiring light as an essential component. Subsequently, IPT results in leaf morphological defects via a GUN1-dependent pathway shared with seedlings undergoing chemical IPT treatments and is restricted to an early window of the leaf development. Collectively, this work advances our understanding of the complexity within plastid retrograde signaling exemplified by sequential signal exchange and consequences that in a particular temporal and spatial context contribute to the modulation of leaf development.
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Affiliation(s)
- Lina Escobar-Tovar
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Morelos, 62210, Mexico
| | - Julio Sierra
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Morelos, 62210, Mexico
| | - Arihel Hernández-Muñoz
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Morelos, 62210, Mexico
| | - Ryan P McQuinn
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA
| | - Sandra Mathioni
- Division of Plant Sciences, University of Missouri-Columbia, Columbia, MO, 65211, USA
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, 0200, Australia
| | - Elizabeth Cordoba
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Morelos, 62210, Mexico
| | - Catherine Colas des Francs-Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Blake C Meyers
- Division of Plant Sciences, University of Missouri-Columbia, Columbia, MO, 65211, USA
- Australian Research Council Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, 0200, Australia
| | - Barry Pogson
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA
| | - Patricia León
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Morelos, 62210, Mexico
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18
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Arabidopsis Mitochondrial Transcription Termination Factor mTERF2 Promotes Splicing of Group IIB Introns. Cells 2021; 10:cells10020315. [PMID: 33546419 PMCID: PMC7913559 DOI: 10.3390/cells10020315] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/29/2021] [Accepted: 01/30/2021] [Indexed: 12/21/2022] Open
Abstract
Plastid gene expression (PGE) is essential for chloroplast biogenesis and function and, hence, for plant development. However, many aspects of PGE remain obscure due to the complexity of the process. A hallmark of nuclear-organellar coordination of gene expression is the emergence of nucleus-encoded protein families, including nucleic-acid binding proteins, during the evolution of the green plant lineage. One of these is the mitochondrial transcription termination factor (mTERF) family, the members of which regulate various steps in gene expression in chloroplasts and/or mitochondria. Here, we describe the molecular function of the chloroplast-localized mTERF2 in Arabidopsis thaliana. The complete loss of mTERF2 function results in embryo lethality, whereas directed, microRNA (amiR)-mediated knockdown of MTERF2 is associated with perturbed plant development and reduced chlorophyll content. Moreover, photosynthesis is impaired in amiR-mterf2 plants, as indicated by reduced levels of photosystem subunits, although the levels of the corresponding messenger RNAs are not affected. RNA immunoprecipitation followed by RNA sequencing (RIP-Seq) experiments, combined with whole-genome RNA-Seq, RNA gel-blot, and quantitative RT-PCR analyses, revealed that mTERF2 is required for the splicing of the group IIB introns of ycf3 (intron 1) and rps12.
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19
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Gawroński P, Burdiak P, Scharff LB, Mielecki J, Górecka M, Zaborowska M, Leister D, Waszczak C, Karpiński S. CIA2 and CIA2-LIKE are required for optimal photosynthesis and stress responses in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 105:619-638. [PMID: 33119927 DOI: 10.1111/tpj.15058] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 10/05/2020] [Accepted: 10/12/2020] [Indexed: 05/22/2023]
Abstract
Chloroplast-to-nucleus retrograde signaling is essential for cell function, acclimation to fluctuating environmental conditions, plant growth and development. The vast majority of chloroplast proteins are nuclear-encoded, and must be imported into the organelle after synthesis in the cytoplasm. This import is essential for the development of fully functional chloroplasts. On the other hand, functional chloroplasts act as sensors of environmental changes and can trigger acclimatory responses that influence nuclear gene expression. Signaling via mobile transcription factors (TFs) has been recently recognized as a way of communication between organelles and the nucleus. In this study, we performed a targeted reverse genetic screen to identify dual-localized TFs involved in chloroplast retrograde signaling during stress responses. We found that CHLOROPLAST IMPORT APPARATUS 2 (CIA2) has a functional plastid transit peptide, and can be located both in chloroplasts and the nucleus. Further, we found that CIA2, along with its homolog CIA2-like (CIL) are involved in the regulation of Arabidopsis responses to UV-AB, high light and heat shock. Finally, our results suggest that both CIA2 and CIL are crucial for chloroplast translation. Our results contribute to a deeper understanding of signaling events in the chloroplast-nucleus cross-talk.
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Affiliation(s)
- Piotr Gawroński
- Department of Plant Genetics, Breeding, and Biotechnology, Warsaw University of Life Sciences, Warsaw, 02-776, Poland
| | - Paweł Burdiak
- Department of Plant Genetics, Breeding, and Biotechnology, Warsaw University of Life Sciences, Warsaw, 02-776, Poland
| | - Lars B Scharff
- Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, 1871, Denmark
| | - Jakub Mielecki
- Department of Plant Genetics, Breeding, and Biotechnology, Warsaw University of Life Sciences, Warsaw, 02-776, Poland
| | - Magdalena Górecka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, Warsaw, 02-106, Poland
| | - Magdalena Zaborowska
- Department of Plant Genetics, Breeding, and Biotechnology, Warsaw University of Life Sciences, Warsaw, 02-776, Poland
| | - Dario Leister
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhadernerstraße 2-4, Planegg-Martinsried, 82152, Germany
| | - Cezary Waszczak
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, Helsinki, 00014, Finland
| | - Stanisław Karpiński
- Department of Plant Genetics, Breeding, and Biotechnology, Warsaw University of Life Sciences, Warsaw, 02-776, Poland
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20
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Gajecka M, Marzec M, Chmielewska B, Jelonek J, Zbieszczyk J, Szarejko I. Changes in plastid biogenesis leading to the formation of albino regenerants in barley microspore culture. BMC PLANT BIOLOGY 2021; 21:22. [PMID: 33413097 PMCID: PMC7792217 DOI: 10.1186/s12870-020-02755-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 11/24/2020] [Indexed: 06/06/2023]
Abstract
BACKGROUND Microspore embryogenesis is potentially the most effective method of obtaining doubled haploids (DH) which are utilized in breeding programs to accelerate production of new cultivars. However, the regeneration of albino plants significantly limits the exploitation of androgenesis for DH production in cereals. Despite many efforts, the precise mechanisms leading to development of albino regenerants have not yet been elucidated. The objective of this study was to reveal the genotype-dependent molecular differences in chloroplast differentiation that lead to the formation of green and albino regenerants in microspore culture of barley. RESULTS We performed a detailed analysis of plastid differentiation at successive stages of androgenesis in two barley cultivars, 'Jersey' and 'Mercada' that differed in their ability to produce green regenerants. We demonstrated the lack of transition from the NEP-dependent to PEP-dependent transcription in plastids of cv. 'Mercada' that produced mostly albino regenerants in microspore culture. The failed NEP-to-PEP transition was associated with the lack of activity of Sig2 gene encoding a sigma factor necessary for transcription of plastid rRNA genes. A very low level of 16S and 23S rRNA transcripts and impaired plastid translation machinery resulted in the inhibition of photomorphogenesis in regenerating embryos and albino regenerants. Furthermore, the plastids present in differentiating 'Mercada' embryos contained a low number of plastome copies whose replication was not always completed. Contrary to 'Mercada', cv. 'Jersey' that produced 90% green regenerants, showed the high activity of PEP polymerase, the highly increased expression of Sig2, plastid rRNAs and tRNAGlu, which indicated the NEP inhibition. The increased expression of GLKs genes encoding transcription factors required for induction of photomorphogenesis was also observed in 'Jersey' regenerants. CONCLUSIONS Proplastids present in microspore-derived embryos of albino-producing genotypes did not pass the early checkpoints of their development that are required for induction of further light-dependent differentiation of chloroplasts. The failed activation of plastid-encoded RNA polymerase during differentiation of embryos was associated with the genotype-dependent inability to regenerate green plants in barley microspore culture. The better understanding of molecular mechanisms underlying formation of albino regenerants may be helpful in overcoming the problem of albinism in cereal androgenesis.
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Affiliation(s)
- Monika Gajecka
- Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia, Jagiellonska 28, Katowice, 40-032, Poland
| | - Marek Marzec
- Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia, Jagiellonska 28, Katowice, 40-032, Poland
| | - Beata Chmielewska
- Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia, Jagiellonska 28, Katowice, 40-032, Poland
| | - Janusz Jelonek
- Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia, Jagiellonska 28, Katowice, 40-032, Poland
| | - Justyna Zbieszczyk
- Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia, Jagiellonska 28, Katowice, 40-032, Poland
| | - Iwona Szarejko
- Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia, Jagiellonska 28, Katowice, 40-032, Poland.
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21
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Vaid N, Ishihara H, Plötner B, Sageman-Furnas K, Wiszniewski A, Laitinen RAE. Leaf chlorosis in Arabidopsis thaliana hybrids is associated with transgenerational decline and imbalanced ribosome number. THE NEW PHYTOLOGIST 2020; 228:989-1000. [PMID: 32557724 DOI: 10.1111/nph.16752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 06/05/2020] [Indexed: 05/09/2023]
Abstract
The interaction of two parental genomes can result in negative outcomes in offspring, also known as hybrid incompatibility. We have previously reported a case in which two recessively interacting alleles result in hybrid chlorosis in Arabidopsis thaliana. A DEAD-box RNA helicase 18 (AtRH18) was identified to be necessary for chlorosis. In this study, we use a sophisticated genetic approach to investigate genes underlying hybrid chlorosis. Sequence comparisons, DNA methylation inhibitor drug treatment and segregation analysis were used to investigate the epigenetic regulation of hybrid chlorosis. Relative rRNA numbers were quantified using real-time quantitative PCR. We confirmed the causality of AtRH18 and provided evidence for the involvement of the promoter region of AtRH18 in the hybrid chlorosis. Furthermore, AtMOM1 from the second parent was identified as the likely candidate gene on chromosome 1. Chlorotic hybrids displayed transgenerational decline in chlorosis, and DNA demethylation experiment restored chlorophyll levels in chlorotic hybrids. Quantification of rRNA indicated that hybrid chlorosis was associated with an imbalance in the ratio of cytosolic and plastid ribosomes. Our findings highlight that the epigenetic regulation of AtRH18 causes hybrid breakdown and provide novel information about the role of AtRH18 in plant development.
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Affiliation(s)
- Neha Vaid
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Hirofumi Ishihara
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Björn Plötner
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Katelyn Sageman-Furnas
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Andrew Wiszniewski
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Roosa A E Laitinen
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
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22
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Feiz L, Strickler SR, van Eck J, Mao L, Movahed N, Taylor C, Gourabathini P, Fei Z, Stern DB. Setaria viridis chlorotic and seedling-lethal mutants define critical functions for chloroplast gene expression. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:917-931. [PMID: 32812296 DOI: 10.1111/tpj.14968] [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: 10/01/2018] [Accepted: 06/24/2020] [Indexed: 06/11/2023]
Abstract
Deep insights into chloroplast biogenesis have been obtained by mutant analysis; however, in C4 plants a relevant mutant collection has only been developed and exploited for maize. Here, we report the initial characterization of an ethyl methyl sulfonate-induced mutant population for the C4 model Setaria viridis. Approximately 1000 M2 families were screened for the segregation of pale-green seedlings in the M3 generation, and a subset of these was identified to be deficient in post-transcriptional steps of chloroplast gene expression. Causative mutations were identified for three lines using deep sequencing-based bulked segregant analysis, and in one case confirmed by transgenic complementation. Using chloroplast RNA-sequencing and other molecular assays, we describe phenotypes of mutants deficient in PSRP7, a plastid-specific ribosomal protein, OTP86, an RNA editing factor, and cpPNP, the chloroplast isozyme of polynucleotide phosphorylase. The psrp mutant is globally defective in chloroplast translation, and has varying deficiencies in the accumulation of chloroplast-encoded proteins. The otp86 mutant, like its Arabidopsis counterpart, is specifically defective in editing of the rps14 mRNA; however, the conditional pale-green mutant phenotype contrasts with the normal growth of the Arabidopsis mutant. The pnp mutant exhibited multiple defects in 3' end maturation as well as other qualitative changes in the chloroplast RNA population. Overall, our collection opens the door to global analysis of photosynthesis and early seedling development in an emerging C4 model.
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Affiliation(s)
- Leila Feiz
- Boyce Thompson Institute, Ithaca, New York, 14853, USA
| | | | - Joyce van Eck
- Boyce Thompson Institute, Ithaca, New York, 14853, USA
| | - Linyong Mao
- Boyce Thompson Institute, Ithaca, New York, 14853, USA
- Department of Biochemistry and Molecular Biology, Howard University, Washington, DC, 20059, USA
| | - Navid Movahed
- Boyce Thompson Institute, Ithaca, New York, 14853, USA
- Q² Solutions, Ithaca, New York, 14850, USA
| | - Caroline Taylor
- Boyce Thompson Institute, Ithaca, New York, 14853, USA
- Lansing High School, Lansing, New York, 14882, USA
- Cornell University, Ithaca, New York, New York, 14850, USA
| | | | - Zhangjun Fei
- Boyce Thompson Institute, Ithaca, New York, 14853, USA
| | - David B Stern
- Boyce Thompson Institute, Ithaca, New York, 14853, USA
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23
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Silva LAS, Sampaio VF, Barbosa LCS, Machado M, Flores-Borges DNA, Sales JF, de Oliveira DC, Mayer JLS, Kuster VC, Rocha DI. Albinism in plants - far beyond the loss of chlorophyll: Structural and physiological aspects of wild-type and albino royal poinciana (Delonix regia) seedlings. PLANT BIOLOGY (STUTTGART, GERMANY) 2020; 22:761-768. [PMID: 32544284 DOI: 10.1111/plb.13146] [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: 02/21/2020] [Accepted: 05/26/2020] [Indexed: 06/11/2023]
Abstract
The partial or complete loss of chlorophylls, or albinism, is a rare phenomenon in plants. In the present study, we provide the first report of the occurrence in albino Delonix regia seedlings and describe the morpho-physiological changes associated with albinism. Wild-type (WT) and albino seedlings were characterized. Leaflets samples were processed following common procedures for analysis with light, scanning and transmission electron microscopy. The chlorophyll a fluorescence parameters and the carbohydrate, lipid and soluble protein content were also determined in leaf and cotyledon samples of both albino and WT seedlings. Albino seedlings showed reduced growth. They also had lower chlorophyll and protein content in foliar tissues than WT seedlings, in addition to lower concentrations of lipids and carbohydrates stored in cotyledons. The chloroplasts of albino seedlings were poorly developed, with an undefined internal membrane system and the presence of plastoglobules. Wild-type seedlings had a uniseriate and hypoestomatic epidermis. The mesophyll was dorsiventral, consisting of a layer of palisade parenchyma and two to four layers of spongy parenchyma. In albino seedlings, the spongy parenchyma was compact, with few intercellular spaces, and the thickness of the mesophyll was larger, resulting in increased thickness of the leaf blade. Albino seedlings had higher stomatal density and number of pavement cells, although the stomata had smaller dimensions. In addition to the partial loss of chlorophylls, albino D. regia showed changes at physiological and structural levels, demonstrating the crucial nature of photosynthetic pigments during the development and differentiation of plant leaf tissues/cells.
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Affiliation(s)
- L A S Silva
- Instituto de Ciências Biológicas, Universidade Federal de Jataí, Jataí, Brazil
| | - V F Sampaio
- Instituto de Ciências Biológicas, Universidade Federal de Jataí, Jataí, Brazil
| | - L C S Barbosa
- Instituto de Ciências Biológicas, Universidade Federal de Jataí, Jataí, Brazil
| | - M Machado
- Instituto de Ciências Biológicas, Universidade Federal de Jataí, Jataí, Brazil
| | - D N A Flores-Borges
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, Brazil
| | - J F Sales
- Instituto Federal Goiano de Educação, Ciência e Tecnologia, Rio Verde, Brazil
| | - D C de Oliveira
- Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Brazil
| | - J L S Mayer
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, Brazil
| | - V C Kuster
- Instituto de Ciências Biológicas, Universidade Federal de Jataí, Jataí, Brazil
| | - D I Rocha
- Instituto de Ciências Biológicas, Universidade Federal de Jataí, Jataí, Brazil
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24
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Dong X, Duan S, Wang H, Jin H. Plastid ribosomal protein LPE2 is involved in photosynthesis and the response to C/N balance in Arabidopsis thaliana. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2020; 62:1418-1432. [PMID: 31944575 PMCID: PMC7540278 DOI: 10.1111/jipb.12907] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 01/09/2020] [Indexed: 05/31/2023]
Abstract
The balance between cellular carbon (C) and nitrogen (N) must be tightly coordinated to sustain optimal growth and development in plants. In chloroplasts, photosynthesis converts inorganic C to organic C, which is important for maintenance of C content in plant cells. However, little is known about the role of chloroplasts in C/N balance. Here, we identified a nuclear-encoded protein LOW PHOTOSYNTHETIC EFFICIENCY2 (LPE2) that it is required for photosynthesis and C/N balance in Arabidopsis. LPE2 is specifically localized in the chloroplast. Both loss-of-function mutants, lpe2-1 and lpe2-2, showed lower photosynthetic activity, characterized by slower electron transport and lower PSII quantum yield than the wild type. Notably, LPE2 is predicted to encode the plastid ribosomal protein S21 (RPS21). Deficiency of LPE2 significantly perturbed the thylakoid membrane composition and plastid protein accumulation, although the transcription of plastid genes is not affected obviously. More interestingly, transcriptome analysis indicated that the loss of LPE2 altered the expression of C and N response related genes in nucleus, which is confirmed by quantitative real-time-polymerase chain reaction. Moreover, deficiency of LPE2 suppressed the response of C/N balance in physiological level. Taken together, our findings suggest that LPE2 plays dual roles in photosynthesis and the response to C/N balance.
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Affiliation(s)
- Xiaoxiao Dong
- School of Life SciencesSun Yat‐sen UniversityGuangzhou510275China
| | - Sujuan Duan
- School of Life SciencesSun Yat‐sen UniversityGuangzhou510275China
- School of Pharmaceutical SciencesGuangzhou University of Chinese MedicineGuangzhou510006China
| | - Hong‐Bin Wang
- School of Life SciencesSun Yat‐sen UniversityGuangzhou510275China
| | - Hong‐Lei Jin
- School of Pharmaceutical SciencesGuangzhou University of Chinese MedicineGuangzhou510006China
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25
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Firmino AAP, Gorka M, Graf A, Skirycz A, Martinez-Seidel F, Zander K, Kopka J, Beine-Golovchuk O. Separation and Paired Proteome Profiling of Plant Chloroplast and Cytoplasmic Ribosomes. PLANTS (BASEL, SWITZERLAND) 2020; 9:E892. [PMID: 32674508 PMCID: PMC7411607 DOI: 10.3390/plants9070892] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/24/2020] [Accepted: 07/09/2020] [Indexed: 12/14/2022]
Abstract
Conventional preparation methods of plant ribosomes fail to resolve non-translating chloroplast or cytoplasmic ribosome subunits from translating fractions. We established preparation of these ribosome complexes from Arabidopsis thaliana leaf, root, and seed tissues by optimized sucrose density gradient centrifugation of protease protected plant extracts. The method co-purified non-translating 30S and 40S ribosome subunits separated non-translating 50S from 60S subunits, and resolved assembled monosomes from low oligomeric polysomes. Combining ribosome fractionation with microfluidic rRNA analysis and proteomics, we characterized the rRNA and ribosomal protein (RP) composition. The identity of cytoplasmic and chloroplast ribosome complexes and the presence of ribosome biogenesis factors in the 60S-80S sedimentation interval were verified. In vivo cross-linking of leaf tissue stabilized ribosome biogenesis complexes, but induced polysome run-off. Omitting cross-linking, the established paired fractionation and proteome analysis monitored relative abundances of plant chloroplast and cytoplasmic ribosome fractions and enabled analysis of RP composition and ribosome associated proteins including transiently associated biogenesis factors.
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Affiliation(s)
- Alexandre Augusto Pereira Firmino
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (M.G.); (A.G.); (A.S.); (F.M.-S.); (K.Z.); (J.K.); (O.B.-G.)
| | - Michal Gorka
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (M.G.); (A.G.); (A.S.); (F.M.-S.); (K.Z.); (J.K.); (O.B.-G.)
| | - Alexander Graf
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (M.G.); (A.G.); (A.S.); (F.M.-S.); (K.Z.); (J.K.); (O.B.-G.)
| | - Aleksandra Skirycz
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (M.G.); (A.G.); (A.S.); (F.M.-S.); (K.Z.); (J.K.); (O.B.-G.)
| | - Federico Martinez-Seidel
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (M.G.); (A.G.); (A.S.); (F.M.-S.); (K.Z.); (J.K.); (O.B.-G.)
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Kerstin Zander
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (M.G.); (A.G.); (A.S.); (F.M.-S.); (K.Z.); (J.K.); (O.B.-G.)
| | - Joachim Kopka
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (M.G.); (A.G.); (A.S.); (F.M.-S.); (K.Z.); (J.K.); (O.B.-G.)
| | - Olga Beine-Golovchuk
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (M.G.); (A.G.); (A.S.); (F.M.-S.); (K.Z.); (J.K.); (O.B.-G.)
- Heidelberg University, Biochemie-Zentrum, Nuclear Pore Complex and Ribosome Assembly, 69120 Heidelberg, Germany
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26
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Martinez-Seidel F, Beine-Golovchuk O, Hsieh YC, Kopka J. Systematic Review of Plant Ribosome Heterogeneity and Specialization. FRONTIERS IN PLANT SCIENCE 2020; 11:948. [PMID: 32670337 PMCID: PMC7332886 DOI: 10.3389/fpls.2020.00948] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 06/10/2020] [Indexed: 05/25/2023]
Abstract
Plants dedicate a high amount of energy and resources to the production of ribosomes. Historically, these multi-protein ribosome complexes have been considered static protein synthesis machines that are not subject to extensive regulation but only read mRNA and produce polypeptides accordingly. New and increasing evidence across various model organisms demonstrated the heterogeneous nature of ribosomes. This heterogeneity can constitute specialized ribosomes that regulate mRNA translation and control protein synthesis. A prominent example of ribosome heterogeneity is seen in the model plant, Arabidopsis thaliana, which, due to genome duplications, has multiple paralogs of each ribosomal protein (RP) gene. We support the notion of plant evolution directing high RP paralog divergence toward functional heterogeneity, underpinned in part by a vast resource of ribosome mutants that suggest specialization extends beyond the pleiotropic effects of single structural RPs or RP paralogs. Thus, Arabidopsis is a highly suitable model to study this phenomenon. Arabidopsis enables reverse genetics approaches that could provide evidence of ribosome specialization. In this review, we critically assess evidence of plant ribosome specialization and highlight steps along ribosome biogenesis in which heterogeneity may arise, filling the knowledge gaps in plant science by providing advanced insights from the human or yeast fields. We propose a data analysis pipeline that infers the heterogeneity of ribosome complexes and deviations from canonical structural compositions linked to stress events. This analysis pipeline can be extrapolated and enhanced by combination with other high-throughput methodologies, such as proteomics. Technologies, such as kinetic mass spectrometry and ribosome profiling, will be necessary to resolve the temporal and spatial aspects of translational regulation while the functional features of ribosomal subpopulations will become clear with the combination of reverse genetics and systems biology approaches.
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Affiliation(s)
- Federico Martinez-Seidel
- Willmitzer Department, Max Planck-Institute of Molecular Plant Physiology, Potsdam, Germany
- School of BioSciences, University of Melbourne, Parkville, VIC, Australia
| | | | - Yin-Chen Hsieh
- Bioinformatics Subdivision, Wageningen University, Wageningen, Netherlands
| | - Joachim Kopka
- Willmitzer Department, Max Planck-Institute of Molecular Plant Physiology, Potsdam, Germany
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27
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Zou M, Mu Y, Chai X, Ouyang M, Yu LJ, Zhang L, Meurer J, Chi W. The critical function of the plastid rRNA methyltransferase, CMAL, in ribosome biogenesis and plant development. Nucleic Acids Res 2020; 48:3195-3210. [PMID: 32095829 PMCID: PMC7102989 DOI: 10.1093/nar/gkaa129] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 02/12/2020] [Accepted: 02/18/2020] [Indexed: 12/12/2022] Open
Abstract
Methylation of nucleotides in ribosomal RNAs (rRNAs) is a ubiquitous feature that occurs in all living organisms. The formation of methylated nucleotides is performed by a variety of RNA-methyltransferases. Chloroplasts of plant cells result from an endosymbiotic event and possess their own genome and ribosomes. However, enzymes responsible for rRNA methylation and the function of modified nucleotides in chloroplasts remain to be determined. Here, we identified an rRNA methyltransferase, CMAL (Chloroplast MraW-Like), in the Arabidopsis chloroplast and investigated its function. CMAL is the Arabidopsis ortholog of bacterial MraW/ RsmH proteins and accounts to the N4-methylation of C1352 in chloroplast 16S rRNA, indicating that CMAL orthologs and this methyl-modification nucleotide is conserved between bacteria and the endosymbiont-derived eukaryotic organelle. The knockout of CMAL in Arabidopsis impairs the chloroplast ribosome accumulation and accordingly reduced the efficiency of mRNA translation. Interestingly, the loss of CMAL leads not only to defects in chloroplast function, but also to abnormal leaf and root development and overall plant morphology. Further investigation showed that CMAL is involved in the plant development probably by modulating auxin derived signaling pathways. This study uncovered the important role of 16S rRNA methylation mediated by CMAL in chloroplast ribosome biogenesis and plant development.
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Affiliation(s)
- Meijuan Zou
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Ying Mu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xin Chai
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Ouyang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Long-Jiang Yu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Lixin Zhang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Jörg Meurer
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University, Munich, D-82152 Planegg-Martinsried, Germany
| | - Wei Chi
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,University of Chinese Academy of Sciences, Beijing 100049, China
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28
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Núñez-Delegido E, Robles P, Ferrández-Ayela A, Quesada V. Functional analysis of mTERF5 and mTERF9 contribution to salt tolerance, plastid gene expression and retrograde signalling in Arabidopsis thaliana. PLANT BIOLOGY (STUTTGART, GERMANY) 2020; 22:459-471. [PMID: 31850621 DOI: 10.1111/plb.13084] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 12/06/2019] [Indexed: 05/16/2023]
Abstract
We previously showed that Arabidopsis mda1 and mterf9 mutants, defective in the chloroplast-targeted mitochondrial transcription termination factors mTERF5 and mTERF9, respectively, display altered responses to abiotic stresses and abscisic acid (ABA), as well as perturbed development, likely through abnormal chloroplast biogenesis. To advance the functional analysis of mTERF5 and mTERF9, we obtained and characterized overexpression (OE) lines. Additionally, we studied genetic interactions between sca3-2, affected in the plastid-RNA polymerase RpoTp, and the mda1-1 and mterf9 mutations. We also investigated the role of mTERF5 and mTERF9 in plastid translation and plastid-to-nucleus signalling. We found that mTERF9 OE reduces salt and ABA tolerance, while mTERF5 or mTERF9 OE alter expression of nuclear and plastid genes. We determined that mda1-1 and mterf9 mutations genetically interact with sca3-2. Further, plastid 16S rRNA levels were reduced in mda1-1 and mterf9 mutants, and mterf9 was more sensitive to chemical inhibitors of chloroplast translation. Expression of the photosynthesis gene LHCB1, a retrograde signalling marker, was differentially affected in mda1-1 and/or mterf9 compared to wild-type Col-0, after treatments with inhibitors of carotenoid biosynthesis (norflurazon) or chloroplast translation (lincomycin). Moreover, mterf9, but not mda1-1, synergistically interacts with gun1-1, defective in GUN1, a central integrator of plastid retrograde signals. Our results show that mTERF9, and to a lesser extent mTERF5, are negative regulators of salt tolerance and that both genes are functionally related to RpoTp, and that mTERF9 is likely required for plastid ribosomal stability and/or assembly. Furthermore, our findings support a role for mTERF9 in retrograde signalling.
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Affiliation(s)
- E Núñez-Delegido
- Instituto de Bioingeniería, Universidad Miguel Hernández, Elche, Spain
| | - P Robles
- Instituto de Bioingeniería, Universidad Miguel Hernández, Elche, Spain
| | - A Ferrández-Ayela
- Instituto de Bioingeniería, Universidad Miguel Hernández, Elche, Spain
| | - V Quesada
- Instituto de Bioingeniería, Universidad Miguel Hernández, Elche, Spain
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29
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Hu S, Ding Y, Zhu C. Sensitivity and Responses of Chloroplasts to Heat Stress in Plants. FRONTIERS IN PLANT SCIENCE 2020; 11:375. [PMID: 32300353 PMCID: PMC7142257 DOI: 10.3389/fpls.2020.00375] [Citation(s) in RCA: 131] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Accepted: 03/16/2020] [Indexed: 05/21/2023]
Abstract
Increased temperatures caused by global warming threaten agricultural production, as warmer conditions can inhibit plant growth and development or even destroy crops in extreme circumstances. Extensive research over the past several decades has revealed that chloroplasts, the photosynthetic organelles of plants, are highly sensitive to heat stress, which affects a variety of photosynthetic processes including chlorophyll biosynthesis, photochemical reactions, electron transport, and CO2 assimilation. Important mechanisms by which plant cells respond to heat stress to protect these photosynthetic organelles have been identified and analyzed. More recent studies have made it clear that chloroplasts play an important role in inducing the expression of nuclear heat-response genes during the heat stress response. In this review, we summarize these important advances in plant-based research and discuss how the sensitivity, responses, and signaling roles of chloroplasts contribute to plant heat sensitivity and tolerance.
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Affiliation(s)
| | | | - Cheng Zhu
- Key Laboratory of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University, Hangzhou, China
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Nagashima Y, Ohshiro K, Iwase A, Nakata MT, Maekawa S, Horiguchi G. The bRPS6-Family Protein RFC3 Prevents Interference by the Splicing Factor CFM3b during Plastid rRNA Biogenesis in Arabidopsis thaliana. PLANTS 2020; 9:plants9030328. [PMID: 32143506 PMCID: PMC7154815 DOI: 10.3390/plants9030328] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 02/24/2020] [Accepted: 03/03/2020] [Indexed: 01/03/2023]
Abstract
Plastid ribosome biogenesis is important for plant growth and development. REGULATOR OF FATTY ACID COMPOSITION3 (RFC3) is a member of the bacterial ribosomal protein S6 family and is important for lateral root development. rfc3-2 dramatically reduces the plastid rRNA level and produces lateral roots that lack stem cells. In this study, we isolated a suppressor of rfc three2 (sprt2) mutant that enabled recovery of most rfc3 mutant phenotypes, including abnormal primary and lateral root development and reduced plastid rRNA level. Northern blotting showed that immature and mature plastid rRNA levels were reduced, with the exception of an early 23S rRNA intermediate, in rfc3-2 mutants. These changes were recovered in rfc3-2 sprt2-1 mutants, but a second defect in the processing of 16S rRNA appeared in this line. The results suggest that rfc3 mutants may be defective in at least two steps of plastid rRNA processing, one of which is specifically affected by the sprt2-1 mutation. sprt2-1 mutants had a mutation in CRM FAMILY MEMBER 3b (CFM3b), which encodes a plastid-localized splicing factor. A bimolecular fluorescence complementation (BiFC) assay suggested that RFC3 and SPRT2/CFM3b interact with each other in plastids. These results suggest that RFC3 suppresses the nonspecific action of SPRT2/CFM3b and improves the accuracy of plastid rRNA processing.
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Affiliation(s)
- Yumi Nagashima
- Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
| | - Katsutomo Ohshiro
- Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
| | - Akiyasu Iwase
- Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
| | - Miyuki T Nakata
- Research Center for Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
- Current address: Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Shugo Maekawa
- Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
- Research Center for Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
| | - Gorou Horiguchi
- Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
- Research Center for Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
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31
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Pilla SP, Bahadur RP. Residue conservation elucidates the evolution of r-proteins in ribosomal assembly and function. Int J Biol Macromol 2019; 140:323-329. [PMID: 31421176 DOI: 10.1016/j.ijbiomac.2019.08.127] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 08/14/2019] [Accepted: 08/14/2019] [Indexed: 02/08/2023]
Abstract
Ribosomes are the translational machineries having two unequal subunits, small subunit (SSU) and large subunit (LSU) across all the domains of life. Origin and evolution of ribosome are encoded in its structure, and the core of the ribosome is highly conserved. Here, we have used Shannon entropy to analyze the evolution of ribosomal proteins (r-proteins) across the three domains of life. Moreover, we have analyzed the residue conservation at protein-protein (PP) and protein-RNA (PR) interfaces in SSU and LSU. Furthermore, we have studied the evolution of early, intermediate and late binding r-proteins. We show that the r-proteins of Thermus thermophilus are better conserved during the evolution. Furthermore, we find the late binders are better conserved than the early and the intermediate binders. The residues at the interior of the r-proteins are the most conserved followed by those at the interface and the solvent accessible surface. Additionally, we show that the residues at the PP interfaces are better conserved than those at the PR interfaces. However, between PR and PP interfaces, the multi-interface residues at the former are better conserved than those at the latter ones. Our findings may provide insights into the evolution of r-proteins in ribosomal assembly and function.
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Affiliation(s)
- Smita P Pilla
- Computational Structural Biology Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Ranjit Prasad Bahadur
- Computational Structural Biology Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India.
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32
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Forsythe ES, Sharbrough J, Havird JC, Warren JM, Sloan DB. CyMIRA: The Cytonuclear Molecular Interactions Reference for Arabidopsis. Genome Biol Evol 2019; 11:2194-2202. [PMID: 31282937 PMCID: PMC6685490 DOI: 10.1093/gbe/evz144] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2019] [Indexed: 12/11/2022] Open
Abstract
The function and evolution of eukaryotic cells depend upon direct molecular interactions between gene products encoded in nuclear and cytoplasmic genomes. Understanding how these cytonuclear interactions drive molecular evolution and generate genetic incompatibilities between isolated populations and species is of central importance to eukaryotic biology. Plants are an outstanding system to investigate such effects because of their two different genomic compartments present in the cytoplasm (mitochondria and plastids) and the extensive resources detailing subcellular targeting of nuclear-encoded proteins. However, the field lacks a consistent classification scheme for mitochondrial- and plastid-targeted proteins based on their molecular interactions with cytoplasmic genomes and gene products, which hinders efforts to standardize and compare results across studies. Here, we take advantage of detailed knowledge about the model angiosperm Arabidopsis thaliana to provide a curated database of plant cytonuclear interactions at the molecular level. CyMIRA (Cytonuclear Molecular Interactions Reference for Arabidopsis) is available at http://cymira.colostate.edu/ and https://github.com/dbsloan/cymira and will serve as a resource to aid researchers in partitioning evolutionary genomic data into functional gene classes based on organelle targeting and direct molecular interaction with cytoplasmic genomes and gene products. It includes 11 categories (and 27 subcategories) of different cytonuclear complexes and types of molecular interactions, and it reports residue-level information for cytonuclear contact sites. We hope that this framework will make it easier to standardize, interpret, and compare studies testing the functional and evolutionary consequences of cytonuclear interactions.
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Affiliation(s)
| | | | - Justin C Havird
- Department of Integrative Biology, University of Texas, Austin
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33
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Arias-Agudelo LM, González F, Isaza JP, Alzate JF, Pabón-Mora N. Plastome reduction and gene content in New World Pilostyles (Apodanthaceae) unveils high similarities to African and Australian congeners. Mol Phylogenet Evol 2019; 135:193-202. [DOI: 10.1016/j.ympev.2019.03.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/22/2019] [Accepted: 03/22/2019] [Indexed: 02/06/2023]
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34
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Bobik K, Fernandez JC, Hardin SR, Ernest B, Ganusova EE, Staton ME, Burch-Smith TM. The essential chloroplast ribosomal protein uL15c interacts with the chloroplast RNA helicase ISE2 and affects intercellular trafficking through plasmodesmata. THE NEW PHYTOLOGIST 2019; 221:850-865. [PMID: 30192000 DOI: 10.1111/nph.15427] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 07/24/2018] [Indexed: 05/07/2023]
Abstract
Chloroplasts retain part of their ancestral genomes and the machinery for expression of those genomes. The nucleus-encoded chloroplast RNA helicase INCREASED SIZE EXCLUSION LIMIT2 (ISE2) is required for chloroplast ribosomal RNA processing and chloro-ribosome assembly. To further elucidate ISE2's role in chloroplast translation, two independent approaches were used to identify its potential protein partners. Both a yeast two-hybrid screen and a pull-down assay identified plastid ribosomal protein L15, uL15c (formerly RPL15), as interacting with ISE2. The interaction was confirmed in vivo by co-immunoprecipitation. Interestingly, we found that rpl15 null mutants do not complete embryogenesis, indicating that RPL15 is an essential gene for autotrophic growth of Arabidopsis thaliana. Arabidopsis and Nicotiana benthamiana plants with reduced expression of RPL15 developed chlorotic leaves, had reduced photosynthetic capacity and exhibited defective chloroplast development. Processing of chloroplast ribosomal RNAs and assembly of ribosomal subunits were disrupted by reduced expression of RPL15. Chloroplast translation was also decreased, reducing accumulation of chloroplast-encoded proteins, in such plants compared to wild-type plants. Notably, knockdown of RPL15 expression increased intercellular trafficking, a phenotype also observed in plants with reduced ISE2 expression. This finding provides further evidence for chloroplast function in modulating intercellular trafficking via plasmodesmata.
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Affiliation(s)
- Krzysztof Bobik
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Jessica C Fernandez
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Sara R Hardin
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Ben Ernest
- School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Elena E Ganusova
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Margaret E Staton
- Department of Entomology and Plant Pathology, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA
| | - Tessa M Burch-Smith
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
- School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37996, USA
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Liu S, Zheng L, Jia J, Guo J, Zheng M, Zhao J, Shao J, Liu X, An L, Yu F, Qi Y. Chloroplast Translation Elongation Factor EF-Tu/SVR11 Is Involved in var2-Mediated Leaf Variegation and Leaf Development in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2019; 10:295. [PMID: 30915096 PMCID: PMC6423176 DOI: 10.3389/fpls.2019.00295] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 02/22/2019] [Indexed: 05/02/2023]
Abstract
Chloroplasts are semiautonomous organelles, retaining their own genomes and gene expression apparatuses but controlled by nucleus genome encoded protein factors during evolution. To analyze the genetic regulatory network of FtsH-mediated chloroplast development in Arabidopsis, a set of suppressor mutants of yellow variegated (var2) have been identified. In this research, we reported the identification of another new var2 suppressor locus, SUPPRESSOR OF VARIEGATION11 (SVR11), which encodes a putative chloroplast-localized prokaryotic type translation elongation factor EF-Tu. SVR11 is likely essential to chloroplast development and plant survival. GUS activity reveals that SVR11 is abundant in the juvenile leaf tissue, lateral roots, and root tips. Interestingly, we found that SVR11 and SVR9 together regulate leaf development, including leaf margin development and cotyledon venation patterns. These findings reinforce the notion that chloroplast translation state triggers retrograde signals regulate not only chloroplast development but also leaf development.
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Janowski M, Zoschke R, Scharff LB, Martinez Jaime S, Ferrari C, Proost S, Ng Wei Xiong J, Omranian N, Musialak-Lange M, Nikoloski Z, Graf A, Schöttler MA, Sampathkumar A, Vaid N, Mutwil M. AtRsgA from Arabidopsis thaliana is important for maturation of the small subunit of the chloroplast ribosome. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 96:404-420. [PMID: 30044525 DOI: 10.1111/tpj.14040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 07/12/2018] [Accepted: 07/17/2018] [Indexed: 05/24/2023]
Abstract
Plastid ribosomes are very similar in structure and function to the ribosomes of their bacterial ancestors. Since ribosome biogenesis is not thermodynamically favorable under biological conditions it requires the activity of many assembly factors. Here we have characterized a homolog of bacterial RsgA in Arabidopsis thaliana and show that it can complement the bacterial homolog. Functional characterization of a strong mutant in Arabidopsis revealed that the protein is essential for plant viability, while a weak mutant produced dwarf, chlorotic plants that incorporated immature pre-16S ribosomal RNA into translating ribosomes. Physiological analysis of the mutant plants revealed smaller, but more numerous, chloroplasts in the mesophyll cells, reduction of chlorophyll a and b, depletion of proplastids from the rib meristem and decreased photosynthetic electron transport rate and efficiency. Comparative RNA sequencing and proteomic analysis of the weak mutant and wild-type plants revealed that various biotic stress-related, transcriptional regulation and post-transcriptional modification pathways were repressed in the mutant. Intriguingly, while nuclear- and chloroplast-encoded photosynthesis-related proteins were less abundant in the mutant, the corresponding transcripts were increased, suggesting an elaborate compensatory mechanism, potentially via differentially active retrograde signaling pathways. To conclude, this study reveals a chloroplast ribosome assembly factor and outlines the transcriptomic and proteomic responses of the compensatory mechanism activated during decreased chloroplast function.
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Affiliation(s)
- Marcin Janowski
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany
| | - Reimo Zoschke
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany
| | - Lars B Scharff
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Silvia Martinez Jaime
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany
| | - Camilla Ferrari
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany
| | - Sebastian Proost
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany
| | - Jonathan Ng Wei Xiong
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
| | - Nooshin Omranian
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany
| | | | - Zoran Nikoloski
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany
- Bioinformatics Group, Institute of Biochemistry and Biology, University of Potsdam, Karl- Liebknecht-Strasse 24-25, 14476, Potsdam-Golm, Germany
| | - Alexander Graf
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany
| | - Mark A Schöttler
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany
| | - Arun Sampathkumar
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany
| | - Neha Vaid
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany
| | - Marek Mutwil
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
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37
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Tang X, Wang Y, Zhang Y, Huang S, Liu Z, Fei D, Feng H. A missense mutation of plastid RPS4 is associated with chlorophyll deficiency in Chinese cabbage (Brassica campestris ssp. pekinensis). BMC PLANT BIOLOGY 2018; 18:130. [PMID: 29940850 PMCID: PMC6019835 DOI: 10.1186/s12870-018-1353-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 06/17/2018] [Indexed: 05/19/2023]
Abstract
BACKGROUND Plastome mutants are ideal resources for elucidating the functions of plastid genes. Numerous studies have been conducted for the function of plastid genes in barley and tobacco; however, related information is limited in Chinese cabbage. RESULTS A chlorophyll-deficient mutant of Chinese cabbage that was derived by ethyl methanesulfonate treatment on isolated microspores showed uniformly pale green inner leaves and slow growth compared with that shown by the wild type "Fukuda 50' ('FT'). Genetic analysis revealed that cdm was cytoplasmically inherited. Physiological and ultrastructural analyses of cdm showed impaired photosynthesis and abnormal chloroplast development. Utilizing next generation sequencing, the complete plastomes of cdm and 'FT' were respectively re-mapped to the reference genome of Chinese cabbage, and an A-to-C base substitution with a mutation ratio higher than 99% was detected. The missense mutation of plastid ribosomal protein S4 led to valine substitution for glycine at residue 193. The expression level of rps4 was analyzed using quantitative real-time PCR and found lower in than in 'FT'. RNA gel-blot assays showed that the abundance of mature 23S rRNA, 16S rRNA, 5S rRNA, and 4.5S rRNA significantly decreased and that the processing of 23S, 16S rRNA, and 4.5S rRNA was seriously impaired, affecting the ribosomal function in cdm. CONCLUSIONS These findings indicated that cdm was a plastome mutant and that chlorophyll deficiency might be due to an A-to-C base substitution of the plastome-encoded rps4 that impaired the rRNA processing and affected the ribosomal function.
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Affiliation(s)
- Xiaoyan Tang
- College of Horticulture, Liaoning Key Lab of Genetics and Breeding for Cruciferous Vegetable Crops, Shenyang Agricultural University, Shenyang, Liaoning 110866 People’s Republic of China
| | - Yiheng Wang
- College of Horticulture, Liaoning Key Lab of Genetics and Breeding for Cruciferous Vegetable Crops, Shenyang Agricultural University, Shenyang, Liaoning 110866 People’s Republic of China
| | - Yun Zhang
- College of Horticulture, Liaoning Key Lab of Genetics and Breeding for Cruciferous Vegetable Crops, Shenyang Agricultural University, Shenyang, Liaoning 110866 People’s Republic of China
| | - Shengnan Huang
- College of Horticulture, Liaoning Key Lab of Genetics and Breeding for Cruciferous Vegetable Crops, Shenyang Agricultural University, Shenyang, Liaoning 110866 People’s Republic of China
| | - Zhiyong Liu
- College of Horticulture, Liaoning Key Lab of Genetics and Breeding for Cruciferous Vegetable Crops, Shenyang Agricultural University, Shenyang, Liaoning 110866 People’s Republic of China
| | - Danli Fei
- College of Horticulture, Liaoning Key Lab of Genetics and Breeding for Cruciferous Vegetable Crops, Shenyang Agricultural University, Shenyang, Liaoning 110866 People’s Republic of China
| | - Hui Feng
- College of Horticulture, Liaoning Key Lab of Genetics and Breeding for Cruciferous Vegetable Crops, Shenyang Agricultural University, Shenyang, Liaoning 110866 People’s Republic of China
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Robles P, Núñez-Delegido E, Ferrández-Ayela A, Sarmiento-Mañús R, Micol JL, Quesada V. Arabidopsis mTERF6 is required for leaf patterning. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 266:117-129. [PMID: 29241561 DOI: 10.1016/j.plantsci.2017.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 10/31/2017] [Accepted: 11/05/2017] [Indexed: 05/21/2023]
Abstract
To enhance our understanding of the roles of mitochondrial transcription termination factors (mTERFs) in plants, we have taken a reverse genetic approach in Arabidopsis thaliana. One of the mutants isolated carried a novel allele of the mTERF6 gene, which we named mterf6-5. mTERF6 is a chloroplast and mitochondrial localised protein required for the maturation of chloroplast isoleucine tRNA. The mterf6-5 plants are pale and exhibit markedly reduced growth, and altered leaf and chloroplast development. Our qRT-PCR analyses revealed mis-expression of several plastid, mitochondrial and nuclear genes in mterf6-5 plants. Synergistic phenotypes were observed in double mutant combinations of mterf6-5 with alleles of other mTERF genes as well as with scabra3-2, affected in the plastid RpoTp RNA polymerase; these observations suggest a functional relationship between mTERF6, other mTERFs and SCA3. The mterf6-5 mutation also enhanced the leaf dorsoventral polarity defects of the asymmetric leaves1-1 (as1-1) mutant, which resulted in radial leaves. This interaction seemed specific of the impaired mTERF6 function because mutations in the mTERF genes MDA1 or TWR-1/mTERF9 did not result in radialised leaves. Furthermore, the mterf6-5 mutation dramatically increased the leaf phenotype of as2-1 and caused lethality early in vegetative development. Our results uncover a new role for mTERF6 in leaf patterning and highlight the importance of mTERFs in plant development.
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Affiliation(s)
- Pedro Robles
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202 Elche, Spain
| | - Eva Núñez-Delegido
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202 Elche, Spain
| | | | - Raquel Sarmiento-Mañús
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202 Elche, Spain
| | - José Luis Micol
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202 Elche, Spain
| | - Víctor Quesada
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202 Elche, Spain.
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Meurer J, Schmid LM, Stoppel R, Leister D, Brachmann A, Manavski N. PALE CRESS binds to plastid RNAs and facilitates the biogenesis of the 50S ribosomal subunit. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 92:400-413. [PMID: 28805278 DOI: 10.1111/tpj.13662] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/04/2017] [Accepted: 08/08/2017] [Indexed: 05/11/2023]
Abstract
The plant-specific PALE CRESS (PAC) protein has previously been shown to be essential for photoautotrophic growth. Here we further investigated the molecular function of the PAC protein. PAC localizes to plastid nucleoids and forms large proteinaceous and RNA-containing megadalton complexes. It co-immunoprecipitates with a specific subset of chloroplast RNAs including psbK-psbI, ndhF, ndhD, and 23S ribosomal RNA (rRNA), as demonstrated by RNA immunoprecipitation in combination with high throughput RNA sequencing (RIP-seq) analyses. Furthermore, it co-migrates with premature 50S ribosomal particles and specifically binds to 23S rRNA in vitro. This coincides with severely reduced levels of 23S rRNA in pac leading to translational deficiencies and related alterations of plastid transcript patterns and abundance similar to plants treated with the translation inhibitor lincomycin. Thus, we conclude that deficiency in plastid ribosomes accounts for the pac phenotype. Moreover, the absence or reduction of PAC levels in the corresponding mutants induces structural changes of the 23S rRNA, as demonstrated by in vivo RNA structure probing. Our results indicate that PAC binds to the 23S rRNA to promote the biogenesis of the 50S subunit.
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Affiliation(s)
- Jörg Meurer
- Plant Sciences, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Lisa-Marie Schmid
- Plant Sciences, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Rhea Stoppel
- Plant Sciences, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Dario Leister
- Plant Sciences, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Andreas Brachmann
- Genetics, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Nikolay Manavski
- Plant Sciences, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
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Ahmed T, Shi J, Bhushan S. Unique localization of the plastid-specific ribosomal proteins in the chloroplast ribosome small subunit provides mechanistic insights into the chloroplastic translation. Nucleic Acids Res 2017; 45:8581-8595. [PMID: 28582576 PMCID: PMC5737520 DOI: 10.1093/nar/gkx499] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 05/26/2017] [Indexed: 12/30/2022] Open
Abstract
Chloroplastic translation is mediated by a bacterial-type 70S chloroplast ribosome. During the evolution, chloroplast ribosomes have acquired five plastid-specific ribosomal proteins or PSRPs (cS22, cS23, bTHXc, cL37 and cL38) which have been suggested to play important regulatory roles in translation. However, their exact locations on the chloroplast ribosome remain elusive due to lack of a high-resolution structure, hindering our progress to understand their possible roles. Here we present a cryo-EM structure of the 70S chloroplast ribosome from spinach resolved to 3.4 Å and focus our discussion mainly on the architecture of the 30S small subunit (SSU) which is resolved to 3.7 Å. cS22 localizes at the SSU foot where it seems to compensate for the deletions in 16S rRNA. The mRNA exit site is highly remodeled due to the presence of cS23 suggesting an alternative mode of translation initiation. bTHXc is positioned at the SSU head and appears to stabilize the intersubunit bridge B1b during thermal fluctuations. The translation factor plastid pY binds to the SSU on the intersubunit side and interacts with the conserved nucleotide bases involved in decoding. Most of the intersubunit bridges are conserved compared to the bacteria, except for a new bridge involving uL2c and bS6c.
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Affiliation(s)
- Tofayel Ahmed
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Jian Shi
- Center for BioImaging Sciences, National University of Singapore, 117546, Singapore
| | - Shashi Bhushan
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore.,NTU Institute of Structural Biology, Nanyang Technological University, 639798, Singapore
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41
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Wang Z, Liu W, Fan G, Zhai X, Zhao Z, Dong Y, Deng M, Cao Y. Quantitative proteome-level analysis of paulownia witches' broom disease with methyl methane sulfonate assistance reveals diverse metabolic changes during the infection and recovery processes. PeerJ 2017; 5:e3495. [PMID: 28690927 PMCID: PMC5497676 DOI: 10.7717/peerj.3495] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 06/02/2017] [Indexed: 12/17/2022] Open
Abstract
Paulownia witches' broom (PaWB) disease caused by phytoplasma is a fatal disease that leads to considerable economic losses. Although there are a few reports describing studies of PaWB pathogenesis, the molecular mechanisms underlying phytoplasma pathogenicity in Paulownia trees remain uncharacterized. In this study, after building a transcriptome database containing 67,177 sequences, we used isobaric tags for relative and absolute quantification (iTRAQ) to quantify and analyze the proteome-level changes among healthy P. fortunei (PF), PaWB-infected P. fortunei (PFI), and PaWB-infected P. fortunei treated with 20 mg L-1 or 60 mg L-1 methyl methane sulfonate (MMS) (PFI-20 and PFI-60, respectively). A total of 2,358 proteins were identified. We investigated the proteins profiles in PF vs. PFI (infected process) and PFI-20 vs. PFI-60 (recovered process), and further found that many of the MMS-response proteins mapped to "photosynthesis" and "ribosome" pathways. Based on our comparison scheme, 36 PaWB-related proteins were revealed. Among them, 32 proteins were classified into three functional groups: (1) carbohydrate and energy metabolism, (2) protein synthesis and degradation, and (3) stress resistance. We then investigated the PaWB-related proteins involved in the infected and recovered processes, and discovered that carbohydrate and energy metabolism was inhibited, and protein synthesis and degradation decreased, as the plant responded to PaWB. Our observations may be useful for characterizing the proteome-level changes that occur at different stages of PaWB disease. The data generated in this study may serve as a valuable resource for elucidating the pathogenesis of PaWB disease during phytoplasma infection and recovery stages.
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Affiliation(s)
- Zhe Wang
- Institute of Paulownia, Henan Agricultural University, Zhengzhou, China
| | - Wenshan Liu
- Institute of Paulownia, Henan Agricultural University, Zhengzhou, China.,College of Forestry, Henan Agricultural University, Zhengzhou, China
| | - Guoqiang Fan
- Institute of Paulownia, Henan Agricultural University, Zhengzhou, China.,College of Forestry, Henan Agricultural University, Zhengzhou, China
| | | | - Zhenli Zhao
- Institute of Paulownia, Henan Agricultural University, Zhengzhou, China.,College of Forestry, Henan Agricultural University, Zhengzhou, China
| | - Yanpeng Dong
- Institute of Paulownia, Henan Agricultural University, Zhengzhou, China.,College of Forestry, Henan Agricultural University, Zhengzhou, China
| | - Minjie Deng
- Institute of Paulownia, Henan Agricultural University, Zhengzhou, China.,College of Forestry, Henan Agricultural University, Zhengzhou, China
| | - Yabing Cao
- Institute of Paulownia, Henan Agricultural University, Zhengzhou, China
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42
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Bobik K, McCray TN, Ernest B, Fernandez JC, Howell KA, Lane T, Staton M, Burch-Smith TM. The chloroplast RNA helicase ISE2 is required for multiple chloroplast RNA processing steps in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 91:114-131. [PMID: 28346704 DOI: 10.1111/tpj.13550] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Revised: 03/14/2017] [Accepted: 03/21/2017] [Indexed: 05/06/2023]
Abstract
INCREASED SIZE EXCLUSION LIMIT2 (ISE2) is a chloroplast-localized RNA helicase that is indispensable for proper plant development. Chloroplasts in leaves with reduced ISE2 expression have previously been shown to exhibit reduced thylakoid contents and increased stromal volume, indicative of defective development. It has recently been reported that ISE2 is required for the splicing of group II introns from chloroplast transcripts. The current study extends these findings, and presents evidence for ISE2's role in multiple aspects of chloroplast RNA processing beyond group II intron splicing. Loss of ISE2 from Arabidopsis thaliana leaves resulted in defects in C-to-U RNA editing, altered accumulation of chloroplast transcripts and chloroplast-encoded proteins, and defective processing of chloroplast ribosomal RNAs. Potential ISE2 substrates were identified by RNA immunoprecipitation followed by next-generation sequencing (RIP-seq), and the diversity of RNA species identified supports ISE2's involvement in multiple aspects of chloroplast RNA metabolism. Comprehensive phylogenetic analyses revealed that ISE2 is a non-canonical Ski2-like RNA helicase that represents a separate sub-clade unique to green photosynthetic organisms, consistent with its function as an essential protein. Thus ISE2's evolutionary conservation may be explained by its numerous roles in regulating chloroplast gene expression.
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Affiliation(s)
- Krzysztof Bobik
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Tyra N McCray
- School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Ben Ernest
- School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Jessica C Fernandez
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Katharine A Howell
- Plant Energy Biology, ARC Center of Excellence, University of Western Australia, Perth, Australia
| | - Thomas Lane
- Department of Entomology and Plant Pathology, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA
| | - Margaret Staton
- School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37996, USA
- Department of Entomology and Plant Pathology, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA
| | - Tessa M Burch-Smith
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
- School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37996, USA
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43
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Yamagishi T, Horie Y, Tatarazako N. Synergism between macrolide antibiotics and the azole fungicide ketoconazole in growth inhibition testing of the green alga Pseudokirchneriella subcapitata. CHEMOSPHERE 2017; 174:1-7. [PMID: 28152378 DOI: 10.1016/j.chemosphere.2017.01.071] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 01/11/2017] [Accepted: 01/12/2017] [Indexed: 06/06/2023]
Abstract
Macrolide antibiotics and azole fungicides are detected widely in the aquatic environment as a result of their increased use in humans and animal livestock disease and their incomplete removal by wastewater treatment plants. In most cases, ecotoxicological tests are performed by using individual chemical substances, but because of the coexistence of a number of chemicals in the environment, organisms are exposed to many chemicals simultaneously. Therefore, it is important to evaluate effects of chemical interactions, adding to potential hazards of individual chemical. Here, we investigated the synergetic effects of combined chemicals (the azole fungicide ketoconazole and either of two macrolide antibiotics, erythromycin and clarithromycin) in growth inhibition testing using Pseudokirchneriella subcapitata according to OECD Test guideline 201. Combination index plots, isobolograms, and curve-shift analyses revealed that the combination of macrolide antibiotic and ketoconazole at various ratios resulted in strong synergism that enhanced growth inhibition of P. subcapitata, suggesting the necessity of investigating potential hazard of combined chemicals for regulatory purposes.
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Affiliation(s)
- Takahiro Yamagishi
- Ecotoxicity Reference Laboratory, Risk Assessment Science Collaboration Office, Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Yoshifumi Horie
- Ecotoxicity Reference Laboratory, Risk Assessment Science Collaboration Office, Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Norihisa Tatarazako
- Ecotoxicity Reference Laboratory, Risk Assessment Science Collaboration Office, Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan.
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44
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Shi X, Hanson MR, Bentolila S. Functional diversity of Arabidopsis organelle-localized RNA-recognition motif-containing proteins. WILEY INTERDISCIPLINARY REVIEWS-RNA 2017; 8. [PMID: 28371504 DOI: 10.1002/wrna.1420] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 02/23/2017] [Accepted: 02/24/2017] [Indexed: 12/20/2022]
Abstract
RNA-Binding Proteins (RBPs) play key roles in plant gene expression and regulation. RBPs contain a variety of RNA-binding motifs, the most abundant and most widespread one in eukaryotes is the RNA recognition motif (RRM). Many nucleus-encoded RRM-containing proteins are transported into chloroplasts and/or mitochondria, and participate in various RNA-related processes in plant organelles. Loss of these proteins can have a detrimental effect on some critical processes such as photosynthesis and respiration, sometimes leading to lethality. Progress has been made in the last few years in understanding the function of particular organelle-localized RRM-containing proteins. Members of the Organelle RRM protein (ORRM, some also characterized as Glycine-Rich RNA-Binding Proteins) family and the Chloroplast RiboNucleoProtein (cpRNP) family, are involved in various types of RNA metabolism, including RNA editing, RNA stability and RNA processing. Organelle-localized RRM proteins also function in plant development and stress responses, in some conditions acting as protein or RNA chaperones. There has been recent progress in characterizing the function of organelle-localized RRM proteins in RNA-related processes and how RRM proteins contribute to the normal growth and development of plants. WIREs RNA 2017, 8:e1420. doi: 10.1002/wrna.1420 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Xiaowen Shi
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Maureen R Hanson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Stephane Bentolila
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
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45
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Cao X, Fan G, Dong Y, Zhao Z, Deng M, Wang Z, Liu W. Proteome Profiling of Paulownia Seedlings Infected with Phytoplasma. FRONTIERS IN PLANT SCIENCE 2017; 8:342. [PMID: 28344590 PMCID: PMC5344924 DOI: 10.3389/fpls.2017.00342] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 02/27/2017] [Indexed: 05/29/2023]
Abstract
Phytoplasma is an insect-transmitted pathogen that causes witches' broom disease in many plants. Paulownia witches' broom is one of the most destructive diseases threatening Paulownia production. The molecular mechanisms associated with this disease have been investigated by transcriptome sequencing, but changes in protein abundance have not been investigated with isobaric tags for relative and absolute quantitation. Previous results have shown that methyl methane sulfonate (MMS) can help Paulownia seedlings recover from the symptoms of witches' broom and reinstate a healthy morphology. In this study, a transcriptomic-assisted proteomic technique was used to analyze the protein changes in phytoplasma-infected Paulownia tomentosa seedlings, phytoplasma-infected seedlings treated with 20 and 60 mg·L-1 MMS, and healthy seedlings. A total of 2,051 proteins were obtained, 879 of which were found to be differentially abundant in pairwise comparisons between the sample groups. Among the differentially abundant proteins, 43 were related to Paulownia witches' broom disease and many of them were annotated to be involved in photosynthesis, expression of dwarf symptom, energy production, and cell signal pathways.
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Affiliation(s)
- Xibing Cao
- Institute of Paulownia, Henan Agricultural UniversityZhengzhou, China
- College of Forestry, Henan Agricultural UniversityZhengzhou, China
| | - Guoqiang Fan
- Institute of Paulownia, Henan Agricultural UniversityZhengzhou, China
- College of Forestry, Henan Agricultural UniversityZhengzhou, China
| | - Yanpeng Dong
- Institute of Paulownia, Henan Agricultural UniversityZhengzhou, China
- College of Forestry, Henan Agricultural UniversityZhengzhou, China
| | - Zhenli Zhao
- Institute of Paulownia, Henan Agricultural UniversityZhengzhou, China
- College of Forestry, Henan Agricultural UniversityZhengzhou, China
| | - Minjie Deng
- Institute of Paulownia, Henan Agricultural UniversityZhengzhou, China
- College of Forestry, Henan Agricultural UniversityZhengzhou, China
| | - Zhe Wang
- Institute of Paulownia, Henan Agricultural UniversityZhengzhou, China
| | - Wenshan Liu
- Institute of Paulownia, Henan Agricultural UniversityZhengzhou, China
- College of Forestry, Henan Agricultural UniversityZhengzhou, China
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46
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Rodrigues NF, Fonseca GCD, Kulcheski FR, Margis R. Salt stress affects mRNA editing in soybean chloroplasts. Genet Mol Biol 2017; 40:200-208. [PMID: 28257523 PMCID: PMC5452132 DOI: 10.1590/1678-4685-gmb-2016-0055] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/20/2016] [Indexed: 11/24/2022] Open
Abstract
Soybean, a crop known by its economic and nutritional importance, has been the
subject of several studies that assess the impact and the effective plant responses
to abiotic stresses. Salt stress is one of the main environmental stresses and
negatively impacts crop growth and yield. In this work, the RNA editing process in
the chloroplast of soybean plants was evaluated in response to a salt stress.
Bioinformatics approach using sRNA and mRNA libraries were employed to detect
specific sites showing differences in editing efficiency. RT-qPCR was used to measure
editing efficiency at selected sites. We observed that transcripts of
NDHA, NDHB, RPS14 and
RPS16 genes presented differences in coverage and editing rates
between control and salt-treated libraries. RT-qPCR assays demonstrated an increase
in editing efficiency of selected genes. The salt stress enhanced the RNA editing
process in transcripts, indicating responses to components of the electron transfer
chain, photosystem and translation complexes. These increases can be a response to
keep the homeostasis of chloroplast protein functions in response to salt stress.
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Affiliation(s)
- Nureyev F Rodrigues
- Departamento de Genética, PPGBM, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Guilherme C da Fonseca
- Centro de Biotecnologia, PPGBCM, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Franceli R Kulcheski
- Centro de Biotecnologia, PPGBCM, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Rogério Margis
- Departamento de Genética, PPGBM, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.,Centro de Biotecnologia, PPGBCM, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.,Departamento de Biofísica, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
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47
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Ferrari R, Tadini L, Moratti F, Lehniger MK, Costa A, Rossi F, Colombo M, Masiero S, Schmitz-Linneweber C, Pesaresi P. CRP1 Protein: (dis)similarities between Arabidopsis thaliana and Zea mays. FRONTIERS IN PLANT SCIENCE 2017; 8:163. [PMID: 28261232 PMCID: PMC5309229 DOI: 10.3389/fpls.2017.00163] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 01/26/2017] [Indexed: 05/25/2023]
Abstract
Biogenesis of chloroplasts in higher plants is initiated from proplastids, and involves a series of processes by which a plastid able to perform photosynthesis, to synthesize amino acids, lipids, and phytohormones is formed. All plastid protein complexes are composed of subunits encoded by the nucleus and chloroplast genomes, which require a coordinated gene expression to produce the correct concentrations of organellar proteins and to maintain organelle function. To achieve this, hundreds of nucleus-encoded factors are imported into the chloroplast to control plastid gene expression. Among these factors, members of the Pentatricopeptide Repeat (PPR) containing protein family have emerged as key regulators of the organellar post-transcriptional processing. PPR proteins represent a large family in plants, and the extent to which PPR functions are conserved between dicots and monocots deserves evaluation, in light of differences in photosynthetic metabolism (C3 vs. C4) and localization of chloroplast biogenesis (mesophyll vs. bundle sheath cells). In this work we investigated the role played in the process of chloroplast biogenesis by At5g42310, a member of the Arabidopsis PPR family which we here refer to as AtCRP1 (Chloroplast RNA Processing 1), providing a comparison with the orthologous ZmCRP1 protein from Zea mays. Loss-of-function atcrp1 mutants are characterized by yellow-albinotic cotyledons and leaves owing to defects in the accumulation of subunits of the thylakoid protein complexes. As in the case of ZmCRP1, AtCRP1 associates with the 5' UTRs of both psaC and, albeit very weakly, petA transcripts, indicating that the role of CRP1 as regulator of chloroplast protein synthesis has been conserved between maize and Arabidopsis. AtCRP1 also interacts with the petB-petD intergenic region and is required for the generation of petB and petD monocistronic RNAs. A similar role has been also attributed to ZmCRP1, although the direct interaction of ZmCRP1 with the petB-petD intergenic region has never been reported, which could indicate that AtCRP1 and ZmCRP1 differ, in part, in their plastid RNA targets.
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Affiliation(s)
- Roberto Ferrari
- Dipartimento di Bioscienze, Università degli studi di MilanoMilano, Italy
| | - Luca Tadini
- Dipartimento di Bioscienze, Università degli studi di MilanoMilano, Italy
| | - Fabio Moratti
- Max-Planck-Institut für Molekulare PflanzenphysiologiePotsdam-Golm, Germany
| | | | - Alex Costa
- Dipartimento di Bioscienze, Università degli studi di MilanoMilano, Italy
| | - Fabio Rossi
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli studi di MilanoMilano, Italy
| | - Monica Colombo
- Centro Ricerca e Innovazione, Fondazione Edmund MachSan Michele all’Adige, Italy
| | - Simona Masiero
- Dipartimento di Bioscienze, Università degli studi di MilanoMilano, Italy
| | | | - Paolo Pesaresi
- Dipartimento di Scienze Agrarie e Ambientali - Produzione, Territorio, Agroenergia, Università degli studi di MilanoMilano, Italy
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48
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Teubner M, Fuß J, Kühn K, Krause K, Schmitz-Linneweber C. The RNA recognition motif protein CP33A is a global ligand of chloroplast mRNAs and is essential for plastid biogenesis and plant development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 89:472-485. [PMID: 27743418 DOI: 10.1111/tpj.13396] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 09/29/2016] [Accepted: 10/07/2016] [Indexed: 06/06/2023]
Abstract
Chloroplast RNA metabolism depends on a multitude of nuclear-encoded RNA-binding proteins (RBPs). Most known chloroplast RBPs address specific RNA targets and RNA-processing functions. However, members of the small chloroplast ribonucleoprotein family (cpRNPs) play a global role in processing and stabilizing chloroplast RNAs. Here, we show that the cpRNP CP33A localizes to a distinct sub-chloroplastic domain and is essential for chloroplast development. The loss of CP33A yields albino seedlings that exhibit aberrant leaf development and can only survive in the presence of an external carbon source. Genome-wide RNA association studies demonstrate that CP33A associates with all chloroplast mRNAs. For a given transcript, quantification of CP33A-bound versus free RNAs demonstrates that CP33A associates with the majority of most mRNAs analyzed. Our results further show that CP33A is required for the accumulation of a number of tested mRNAs, and is particularly relevant for unspliced and unprocessed precursor mRNAs. Finally, CP33A fails to associate with polysomes or to strongly co-precipitate with ribosomal RNA, suggesting that it defines a ribodomain that is separate from the chloroplast translation machinery. Collectively, these findings suggest that CP33A contributes to globally essential RNA processes in the chloroplasts of higher plants.
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Affiliation(s)
- Marlene Teubner
- Humboldt-Universität Berlin, Institut für Biologie, Chausseestrasse 117, 10115, Berlin, Germany
| | - Janina Fuß
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Dramsvegen 201, 9037, Tromsø, Norway
| | - Kristina Kühn
- Humboldt-Universität Berlin, Institut für Biologie, Chausseestrasse 117, 10115, Berlin, Germany
| | - Kirsten Krause
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Dramsvegen 201, 9037, Tromsø, Norway
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49
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Bieri P, Leibundgut M, Saurer M, Boehringer D, Ban N. The complete structure of the chloroplast 70S ribosome in complex with translation factor pY. EMBO J 2016; 36:475-486. [PMID: 28007896 PMCID: PMC5694952 DOI: 10.15252/embj.201695959] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 11/24/2016] [Accepted: 11/28/2016] [Indexed: 01/21/2023] Open
Abstract
Chloroplasts are cellular organelles of plants and algae that are responsible for energy conversion and carbon fixation by the photosynthetic reaction. As a consequence of their endosymbiotic origin, they still contain their own genome and the machinery for protein biosynthesis. Here, we present the atomic structure of the chloroplast 70S ribosome prepared from spinach leaves and resolved by cryo‐EM at 3.4 Å resolution. The complete structure reveals the features of the 4.5S rRNA, which probably evolved by the fragmentation of the 23S rRNA, and all five plastid‐specific ribosomal proteins. These proteins, required for proper assembly and function of the chloroplast translation machinery, bind and stabilize rRNA including regions that only exist in the chloroplast ribosome. Furthermore, the structure reveals plastid‐specific extensions of ribosomal proteins that extensively remodel the mRNA entry and exit site on the small subunit as well as the polypeptide tunnel exit and the putative binding site of the signal recognition particle on the large subunit. The translation factor pY, involved in light‐ and temperature‐dependent control of protein synthesis, is bound to the mRNA channel of the small subunit and interacts with 16S rRNA nucleotides at the A‐site and P‐site, where it protects the decoding centre and inhibits translation by preventing tRNA binding. The small subunit is locked by pY in a non‐rotated state, in which the intersubunit bridges to the large subunit are stabilized.
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Affiliation(s)
- Philipp Bieri
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Marc Leibundgut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Martin Saurer
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Daniel Boehringer
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
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50
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Cryo-EM structure of the large subunit of the spinach chloroplast ribosome. Sci Rep 2016; 6:35793. [PMID: 27762343 PMCID: PMC5071890 DOI: 10.1038/srep35793] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/04/2016] [Indexed: 12/16/2022] Open
Abstract
Protein synthesis in the chloroplast is mediated by the chloroplast ribosome (chloro-ribosome). Overall architecture of the chloro-ribosome is considerably similar to the Escherichia coli (E. coli) ribosome but certain differences are evident. The chloro-ribosome proteins are generally larger because of the presence of chloroplast-specific extensions in their N- and C-termini. The chloro-ribosome harbours six plastid-specific ribosomal proteins (PSRPs); four in the small subunit and two in the large subunit. Deletions and insertions occur throughout the rRNA sequence of the chloro-ribosome (except for the conserved peptidyl transferase center region) but the overall length of the rRNAs do not change significantly, compared to the E. coli. Although, recent advancements in cryo-electron microscopy (cryo-EM) have provided detailed high-resolution structures of ribosomes from many different sources, a high-resolution structure of the chloro-ribosome is still lacking. Here, we present a cryo-EM structure of the large subunit of the chloro-ribosome from spinach (Spinacia oleracea) at an average resolution of 3.5 Å. High-resolution map enabled us to localize and model chloro-ribosome proteins, chloroplast-specific protein extensions, two PSRPs (PSRP5 and 6) and three rRNA molecules present in the chloro-ribosome. Although comparable to E. coli, the polypeptide tunnel and the tunnel exit site show chloroplast-specific features.
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