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Inazu M, Nemoto T, Omata Y, Suzuki S, Ono S, Kanno Y, Seo M, Oikawa A, Masuda S. Complete Loss of RelA and SpoT Homologs in Arabidopsis Reveals the Importance of the Plastidial Stringent Response in the Interplay between Chloroplast Metabolism and Plant Defense Response. PLANT & CELL PHYSIOLOGY 2024; 65:631-643. [PMID: 37925598 DOI: 10.1093/pcp/pcad136] [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: 06/20/2022] [Revised: 10/23/2023] [Accepted: 10/30/2023] [Indexed: 11/06/2023]
Abstract
The highly phosphorylated nucleotide, guanosine tetraphosphate (ppGpp), functions as a secondary messenger in bacteria and chloroplasts. The accumulation of ppGpp alters plastidial gene expression and metabolism, which are required for proper photosynthetic regulation and robust plant growth. However, because four plastid-localized ppGpp synthases/hydrolases function redundantly, the impact of the loss of ppGpp-dependent stringent response on plant physiology remains unclear. We used CRISPR/Cas9 technology to generate an Arabidopsis thaliana mutant lacking all four ppGpp synthases/hydrolases and characterized its phenotype. The mutant showed over 20-fold less ppGpp levels than the wild type under normal growth conditions and exhibited leaf chlorosis and increased expression of defense-related genes as well as salicylic acid and jasmonate levels upon transition to nitrogen-starvation conditions. These results demonstrate that proper levels of ppGpp in plastids are required for controlling not only plastid metabolism but also phytohormone signaling, which is essential for plant defense.
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Affiliation(s)
- Masataka Inazu
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Takanari Nemoto
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Yuto Omata
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Sae Suzuki
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Sumire Ono
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Yuri Kanno
- RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045 Japan
| | - Mitsunori Seo
- RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045 Japan
| | - Akira Oikawa
- Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502 Japan
| | - Shinji Masuda
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
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2
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Turkan S, Kulasek M, Zienkiewicz A, Mierek-Adamska A, Skrzypek E, Warchoł M, Szydłowska-Czerniak A, Bartoli J, Field B, Dąbrowska GB. Guanosine tetraphosphate (ppGpp) is a new player in Brassica napus L. seed development. Food Chem 2024; 436:137648. [PMID: 37852071 DOI: 10.1016/j.foodchem.2023.137648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/23/2023] [Accepted: 09/30/2023] [Indexed: 10/20/2023]
Abstract
Rapeseed oil, constituting 12% of global vegetable oil production, is susceptible to quality degradation due to stress-induced incomplete seed degreening, fatty acid oxidation, or poor nutrient accumulation. We hypothesise that the hyperphosphorylated nucleotide alarmone ppGpp (guanosine tetraphosphate), acts as a pivotal regulator of these processes, given its established roles in nutrient management, degreening, and ROS regulation in leaves. Using qPCR, UHPLC-MS/MS, and biochemical methods, our study delves into the impact of ppGpp on seed nutritional value. We observed a positive correlation between ppGpp levels and desiccation, and a negative correlation with photosynthetic pigment levels. Trends in antioxidant activity suggest that ppGpp may negatively influence peroxidases, which are safeguarding against chlorophyll decomposition. Notably, despite increasing ppGpp levels, sugars, proteins and oils appear unaffected. This newfound role of ppGpp in seed development suggests it regulates the endogenous antioxidant system during degreening and desiccation, preserving nutritional quality. Further validation through mutant-based research is needed.
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Affiliation(s)
- Sena Turkan
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland.
| | - Milena Kulasek
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland.
| | - Agnieszka Zienkiewicz
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland.
| | - Agnieszka Mierek-Adamska
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland.
| | - Edyta Skrzypek
- Department of Biotechnology, The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239 Kraków, Poland.
| | - Marzena Warchoł
- Department of Biotechnology, The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239 Kraków, Poland.
| | - Aleksandra Szydłowska-Czerniak
- Department of Analytical Chemistry and Applied Spectroscopy, Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland.
| | - Julia Bartoli
- Aix Marseille Univ, CNRS, LISM, UMR7255, IMM FR 3479, 31 Chemin Joseph Aiguier, 13009 Marseille, France.
| | - Ben Field
- Aix-Marseille Univ, CEA, CNRS, BIAM, UMR7265, 13009 Marseille, France.
| | - Grażyna B Dąbrowska
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland.
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3
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Garstecka Z, Antoszewski M, Mierek-Adamska A, Krauklis D, Niedojadło K, Kaliska B, Hrynkiewicz K, Dąbrowska GB. Trichoderma viride Colonizes the Roots of Brassica napus L., Alters the Expression of Stress-Responsive Genes, and Increases the Yield of Canola under Field Conditions during Drought. Int J Mol Sci 2023; 24:15349. [PMID: 37895028 PMCID: PMC10607854 DOI: 10.3390/ijms242015349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 10/11/2023] [Accepted: 10/17/2023] [Indexed: 10/29/2023] Open
Abstract
In this work, we present the results of the inoculation of canola seeds (Brassica napus L.) with Trichoderma viride strains that promote the growth of plants. Seven morphologically different strains of T. viride (TvI-VII) were shown to be capable of synthesizing auxins and exhibited cellulolytic and pectinolytic activities. To gain a deeper insight into the molecular mechanisms underlying canola-T. viride interactions, we analyzed the canola stress genes metallothioneins (BnMT1-3) and stringent response genes (BnRSH1-3 and BnCRSH). We demonstrated the presence of cis-regulatory elements responsive to fungal elicitors in the promoter regions of B. napus MT and RSH genes and observed changes in the levels of the transcripts of the above-mentioned genes in response to root colonization by the tested fungal strains. Of the seven tested strains, under laboratory conditions, T. viride VII stimulated the formation of roots and the growth of canola seedlings to the greatest extent. An experiment conducted under field conditions during drought showed that the inoculation of canola seeds with a suspension of T. viride VII spores increased yield by 16.7%. There was also a positive effect of the fungus on the height and branching of the plants, the number of siliques, and the mass of a thousand seeds. We suggest that the T. viride strain TvVII can be used in modern sustainable agriculture as a bioinoculant and seed coating to protect B. napus from drought.
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Affiliation(s)
- Zuzanna Garstecka
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; (Z.G.); (M.A.); (A.M.-A.)
| | - Marcel Antoszewski
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; (Z.G.); (M.A.); (A.M.-A.)
| | - Agnieszka Mierek-Adamska
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; (Z.G.); (M.A.); (A.M.-A.)
| | - Daniel Krauklis
- Research Centre for Cultivar Testing in Słupia Wielka, Chrząstowo 8, 89-100 Nakło nad Notecią, Poland
| | - Katarzyna Niedojadło
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland;
| | - Beata Kaliska
- Research Centre for Cultivar Testing in Słupia Wielka, Chrząstowo 8, 89-100 Nakło nad Notecią, Poland
| | - Katarzyna Hrynkiewicz
- Department of Microbiology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland
| | - Grażyna B. Dąbrowska
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; (Z.G.); (M.A.); (A.M.-A.)
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Qiu D, Lange E, Haas TM, Prucker I, Masuda S, Wang YL, Felix G, Schaaf G, Jessen HJ. Bacterial Pathogen Infection Triggers Magic Spot Nucleotide Signaling in Arabidopsis thaliana Chloroplasts through Specific RelA/SpoT Homologues. J Am Chem Soc 2023. [PMID: 37437195 PMCID: PMC10375528 DOI: 10.1021/jacs.3c04445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Magic spot nucleotides (p)ppGpp are important signaling molecules in bacteria and plants. In the latter, RelA-SpoT homologue (RSH) enzymes are responsible for (p)ppGpp turnover. Profiling of (p)ppGpp is more difficult in plants than in bacteria due to lower concentrations and more severe matrix effects. Here, we report that capillary electrophoresis mass spectrometry (CE-MS) can be deployed to study (p)ppGpp abundance and identity in Arabidopsis thaliana. This goal is achieved by combining a titanium dioxide extraction protocol and pre-spiking with chemically synthesized stable isotope-labeled internal reference compounds. The high sensitivity and separation efficiency of CE-MS enables monitoring of changes in (p)ppGpp levels in A. thaliana upon infection with the pathogen Pseudomonas syringae pv. tomato (PstDC3000). We observed a significant increase of ppGpp post infection that is also stimulated by the flagellin peptide flg22 only. This increase depends on functional flg22 receptor FLS2 and its interacting kinase BAK1 indicating that pathogen-associated molecular pattern (PAMP) receptor-mediated signaling controls ppGpp levels. Transcript analyses showed an upregulation of RSH2 upon flg22 treatment and both RSH2 and RSH3 after PstDC3000 infection. Arabidopsis mutants deficient in RSH2 and RSH3 activity display no ppGpp accumulation upon infection and flg22 treatment, supporting the involvement of these synthases in PAMP-triggered innate immune responses to pathogens within the chloroplast.
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Affiliation(s)
- Danye Qiu
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Freiburg, 79104 Freiburg, Germany
- CIBSS─Centre for Integrative Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Esther Lange
- Institute of Crop Science and Resource Conservation, Department of Plant Nutrition, University of Bonn, 53115 Bonn, Germany
| | - Thomas M Haas
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Freiburg, 79104 Freiburg, Germany
| | - Isabel Prucker
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Freiburg, 79104 Freiburg, Germany
| | - Shinji Masuda
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Yan L Wang
- Institute of Plant Biochemistry, Center for Plant Molecular Biology (ZMBP), Department of Biology, University of Tübingen, 72076 Tübingen, Germany
| | - Georg Felix
- Institute of Plant Biochemistry, Center for Plant Molecular Biology (ZMBP), Department of Biology, University of Tübingen, 72076 Tübingen, Germany
| | - Gabriel Schaaf
- Institute of Crop Science and Resource Conservation, Department of Plant Nutrition, University of Bonn, 53115 Bonn, Germany
| | - Henning J Jessen
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Freiburg, 79104 Freiburg, Germany
- CIBSS─Centre for Integrative Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany
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5
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Iwai R, Uchida S, Yamaguchi S, Nagata D, Koga A, Hayashi S, Yamamoto S, Miyasaka H. Effects of LPS from Rhodobacter sphaeroides, a Purple Non-Sulfur Bacterium (PNSB), on the Gene Expression of Rice Root. Microorganisms 2023; 11:1676. [PMID: 37512850 PMCID: PMC10383378 DOI: 10.3390/microorganisms11071676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/18/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023] Open
Abstract
The effects of lipopolysaccharide (LPS) from Rhodobacter sphaeroides, a purple non-sulfur bacterium (PNSB), on the gene expression of the root of rice (Oryza sativa) were investigated by next generation sequencing (NGS) RNA-seq analysis. The rice seeds were germinated on agar plates containing 10 pg/mL of LPS from Rhodobacter sphaeroides NBRC 12203 (type culture). Three days after germination, RNA samples were extracted from the roots and analyzed by RNA-seq. The effects of dead (killed) PNSB cells of R. sphaeroides NBRC 12203T at the concentration of 101 cfu/mL (ca. 50 pg cell dry weight/mL) were also examined. Clean reads of NGS were mapped to rice genome (number of transcript ID: 44785), and differentially expressed genes were analyzed by DEGs. As a result of DEG analysis, 300 and 128 genes, and 86 and 8 genes were significantly up- and down-regulated by LPS and dead cells of PNSB, respectively. The plot of logFC (fold change) values of the up-regulated genes of LPS and PNSB dead cells showed a significant positive relationship (r2 = 0.6333, p < 0.0001), indicating that most of the effects of dead cell were attributed to those of LPS. Many genes related to tolerance against biotic (fungal and bacterial pathogens) and abiotic (cold, drought, and high salinity) stresses were up-regulated, and the most strikingly up-regulated genes were those involved in the jasmonate signaling pathway, and the genes of chalcone synthase isozymes, indicating that PNSB induced defense response against biotic and abiotic stresses via the jasmonate signaling pathway, despite the non-pathogenicity of PNSB.
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Affiliation(s)
- Ranko Iwai
- Department of Applied Life Science, Sojo University, 4-22-1 Ikeda, Nishiku, Kumamoto 860-0082, Japan
| | - Shunta Uchida
- Department of Applied Life Science, Sojo University, 4-22-1 Ikeda, Nishiku, Kumamoto 860-0082, Japan
| | - Sayaka Yamaguchi
- Department of Applied Life Science, Sojo University, 4-22-1 Ikeda, Nishiku, Kumamoto 860-0082, Japan
| | - Daiki Nagata
- Department of Applied Life Science, Sojo University, 4-22-1 Ikeda, Nishiku, Kumamoto 860-0082, Japan
| | - Aoi Koga
- Ciamo Co., Ltd., G-2F Sojo University, 4-22-1 Ikeda, Nishiku, Kumamoto 860-0082, Japan
| | - Shuhei Hayashi
- Department of Applied Life Science, Sojo University, 4-22-1 Ikeda, Nishiku, Kumamoto 860-0082, Japan
| | - Shinjiro Yamamoto
- Department of Applied Life Science, Sojo University, 4-22-1 Ikeda, Nishiku, Kumamoto 860-0082, Japan
| | - Hitoshi Miyasaka
- Department of Applied Life Science, Sojo University, 4-22-1 Ikeda, Nishiku, Kumamoto 860-0082, Japan
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6
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Mehrez M, Romand S, Field B. New perspectives on the molecular mechanisms of stress signalling by the nucleotide guanosine tetraphosphate (ppGpp), an emerging regulator of photosynthesis in plants and algae. THE NEW PHYTOLOGIST 2023; 237:1086-1099. [PMID: 36349398 PMCID: PMC10107265 DOI: 10.1111/nph.18604] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
The nucleotides guanosine tetraphosphate and guanosine pentaphosphate (together (p)ppGpp) are found in a wide range of prokaryotic and eukaryotic organisms where they are associated with stress signalling. In this review, we will discuss recent research highlighting the role of (p)ppGpp signalling as a conserved regulator of photosynthetic activity in the chloroplasts of plants and algae, and the latest discoveries that open up new perspectives on the emerging roles of (p)ppGpp in acclimation to environmental stress. We explore how rapid advances in the study of (p)ppGpp signalling in prokaryotes are now revealing large gaps in our understanding of the molecular mechanisms of signalling by (p)ppGpp and related nucleotides in plants and algae. Filling in these gaps is likely to lead to the discovery of conserved as well as new plant- and algal-specific (p)ppGpp signalling mechanisms that will offer new insights into the taming of the chloroplast and the regulation of stress tolerance.
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Affiliation(s)
- Marwa Mehrez
- Aix‐Marseille University, CEA, CNRS, BIAM, UMR726513009MarseilleFrance
- Faculty of Sciences of Tunis, Laboratory of Molecular Genetics, Immunology and BiotechnologyUniversity of Tunis El Manar2092TunisTunisia
| | - Shanna Romand
- Aix‐Marseille University, CEA, CNRS, BIAM, UMR726513009MarseilleFrance
| | - Ben Field
- Aix‐Marseille University, CEA, CNRS, BIAM, UMR726513009MarseilleFrance
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7
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Mu H, Han F, Wang Q, Wang Y, Dai X, Zhu M. Recent functional insights into the magic role of (p)ppGpp in growth control. Comput Struct Biotechnol J 2022; 21:168-175. [PMID: 36544478 PMCID: PMC9747358 DOI: 10.1016/j.csbj.2022.11.063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
Rapid growth and survival are two key traits that enable bacterial cells to thrive in their natural habitat. The guanosine tetraphosphate and pentaphosphate [(p)ppGpp], also known as "magic spot", is a key second messenger inside bacterial cells as well as chloroplasts of plants and green algae. (p)ppGpp not only controls various stages of central dogma processes (replication, transcription, ribosome maturation and translation) and central metabolism but also regulates various physiological processes such as pathogenesis, persistence, motility and competence. Under extreme conditions such as nutrient starvation, (p)ppGpp-mediated stringent response is crucial for the survival of bacterial cells. This mini-review highlights some of the very recent progress on the key role of (p)ppGpp in bacterial growth control in light of cellular resource allocation and cell size regulation. We also briefly discuss some recent functional insights into the role of (p)ppGpp in plants and green algae from the angle of growth and development and further discuss several important open directions for future studies.
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Cheung MY, Li X, Ku YS, Chen Z, Lam HM. Co-crystalization reveals the interaction between AtYchF1 and ppGpp. Front Mol Biosci 2022; 9:1061350. [PMID: 36533075 PMCID: PMC9748339 DOI: 10.3389/fmolb.2022.1061350] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 11/07/2022] [Indexed: 08/18/2023] Open
Abstract
AtYchF1 is an unconventional G-protein in Arabidopsis thaliana that exhibits relaxed nucleotide-binding specificity. The bindings between AtYchF1 and biomolecules including GTP, ATP, and 26S rRNA have been reported. In this study, we demonstrated the binding of AtYchF1 to ppGpp in addition to the above molecules. AtYchF1 is a cytosolic protein previously reported as a negative regulator of both biotic and abiotic stresses while the accumulation of ppGpp in the cytoplasm induces retarded plant growth and development. By co-crystallization, in vitro pull-down experiments, and hydrolytic biochemical assays, we demonstrated the binding and hydrolysis of ppGpp by AtYchF1. ppGpp inhibits the binding of AtYchF1 to ATP, GTP, and 26S rRNA. The ppGpp hydrolyzing activity of AtYchF1 failed to be activated by AtGAP1. The AtYchF1-ppGpp co-crystal structure suggests that ppGpp might prevent His136 from executing nucleotide hydrolysis. In addition, upon the binding of ppGpp, the conformation between the TGS and helical domains of AtYchF1 changes. Such structural changes probably influence the binding between AtYchF1 and other molecules such as 26S rRNA. Since YchF proteins are conserved among different kingdoms of life, the findings advance the knowledge on the role of AtYchF1 in regulating nucleotide signaling as well as hint at the possible involvement of YchF proteins in regulating ppGpp level in other species.
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Affiliation(s)
- Ming-Yan Cheung
- Center for Soybean Research of the State Key Laboratory of Agrobiotechnology and School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Xiaorong Li
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Yee-Shan Ku
- Center for Soybean Research of the State Key Laboratory of Agrobiotechnology and School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Zhongzhou Chen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Hon-Ming Lam
- Center for Soybean Research of the State Key Laboratory of Agrobiotechnology and School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
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9
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Harchouni S, England S, Vieu J, Romand S, Aouane A, Citerne S, Legeret B, Alric J, Li-Beisson Y, Menand B, Field B. Guanosine tetraphosphate (ppGpp) accumulation inhibits chloroplast gene expression and promotes super grana formation in the moss Physcomitrium (Physcomitrella) patens. THE NEW PHYTOLOGIST 2022; 236:86-98. [PMID: 35715975 DOI: 10.1111/nph.18320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 06/08/2022] [Indexed: 06/15/2023]
Abstract
The nucleotides guanosine tetraphosphate and pentaphosphate (or (p)ppGpp) are implicated in the regulation of chloroplast function in plants. (p)ppGpp signalling is best understood in the model vascular plant Arabidopsis thaliana in which it acts to regulate plastid gene expression to influence photosynthesis, plant development and immunity. However, little information is known about the conservation or diversity of (p)ppGpp signalling in other land plants. We studied the function of ppGpp in the moss Physcomitrium (previously Physcomitrella) patens using an inducible system for triggering ppGpp accumulation. We used this approach to investigate the effects of ppGpp on chloroplast function, photosynthesis and growth. We demonstrate that ppGpp accumulation causes a dramatic drop in photosynthetic capacity by inhibiting chloroplast gene expression. This was accompanied by the unexpected reorganisation of the thylakoid system into super grana. Surprisingly, these changes did not affect gametophore growth, suggesting that bryophytes and vascular plants may have different tolerances to defects in photosynthesis. Our findings point to the existence of both highly conserved and more specific targets of (p)ppGpp signalling in the land plants that may reflect different growth strategies.
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Affiliation(s)
- Seddik Harchouni
- Aix-Marseille Université, CEA, CNRS, BIAM, UMR7265, 13009, Marseille, France
| | - Samantha England
- Aix-Marseille Université, CEA, CNRS, BIAM, UMR7265, 13009, Marseille, France
| | - Julien Vieu
- Aix-Marseille Université, CEA, CNRS, BIAM, UMR7265, 13009, Marseille, France
| | - Shanna Romand
- Aix-Marseille Université, CEA, CNRS, BIAM, UMR7265, 13009, Marseille, France
| | - Aicha Aouane
- Aix-Marseille Université, CNRS, Institut de Biologie du Developpement de Marseille (IBDM), 13009, Marseille, France
| | - Sylvie Citerne
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000, Versailles, France
| | - Bertrand Legeret
- Aix-Marseille Université, CEA, CNRS, BIAM, UMR7265, CEA Cadarache, Saint-Paul-lez Durance, 13108, France
| | - Jean Alric
- Aix-Marseille Université, CEA, CNRS, BIAM, UMR7265, CEA Cadarache, Saint-Paul-lez Durance, 13108, France
| | - Yonghua Li-Beisson
- Aix-Marseille Université, CEA, CNRS, BIAM, UMR7265, CEA Cadarache, Saint-Paul-lez Durance, 13108, France
| | - Benoît Menand
- Aix-Marseille Université, CEA, CNRS, BIAM, UMR7265, 13009, Marseille, France
| | - Benjamin Field
- Aix-Marseille Université, CEA, CNRS, BIAM, UMR7265, 13009, Marseille, France
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10
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Jan M, Liu Z, Rochaix JD, Sun X. Retrograde and anterograde signaling in the crosstalk between chloroplast and nucleus. FRONTIERS IN PLANT SCIENCE 2022; 13:980237. [PMID: 36119624 PMCID: PMC9478734 DOI: 10.3389/fpls.2022.980237] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 08/18/2022] [Indexed: 06/02/2023]
Abstract
The chloroplast is a complex cellular organelle that not only performs photosynthesis but also synthesizes amino acids, lipids, and phytohormones. Nuclear and chloroplast genetic activity are closely coordinated through signaling chains from the nucleus to chloroplast, referred to as anterograde signaling, and from chloroplast to the nucleus, named retrograde signaling. The chloroplast can act as an environmental sensor and communicates with other cell compartments during its biogenesis and in response to stress, notably with the nucleus through retrograde signaling to regulate nuclear gene expression in response to developmental cues and stresses that affect photosynthesis and growth. Although several components involved in the generation and transmission of plastid-derived retrograde signals and in the regulation of the responsive nuclear genes have been identified, the plastid retrograde signaling network is still poorly understood. Here, we review the current knowledge on multiple plastid retrograde signaling pathways, and on potential plastid signaling molecules. We also discuss the retrograde signaling-dependent regulation of nuclear gene expression within the frame of a multilayered network of transcription factors.
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Affiliation(s)
- Masood Jan
- State Key Laboratory of Cotton Biology and State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Zhixin Liu
- State Key Laboratory of Cotton Biology and State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Jean-David Rochaix
- Department of Molecular Biology and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Xuwu Sun
- State Key Laboratory of Cotton Biology and State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
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11
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Ito K, Ito D, Goto M, Suzuki S, Masuda S, Iba K, Kusumi K. Regulation of ppGpp Synthesis and Its Impact on Chloroplast Biogenesis during Early Leaf Development in Rice. PLANT & CELL PHYSIOLOGY 2022; 63:919-931. [PMID: 35428891 DOI: 10.1093/pcp/pcac053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 04/13/2022] [Accepted: 04/15/2022] [Indexed: 06/14/2023]
Abstract
Guanosine tetraphosphate (ppGpp) is known as an alarmone that mediates bacterial stress responses. In plants, ppGpp is synthesized in chloroplasts from GTP and ATP and functions as a regulator of chloroplast gene expression to affect photosynthesis and plant growth. This observation indicates that ppGpp metabolism is closely related to chloroplast function, but the regulation of ppGpp and its role in chloroplast differentiation are not well understood. In rice, ppGpp directly inhibits plastidial guanylate kinase (GKpm), a key enzyme in GTP biosynthesis. GKpm is highly expressed during early leaf development in rice, and the GKpm-deficient mutant, virescent-2 (v2), develops chloroplast-deficient chlorotic leaves under low-temperature conditions. To examine the relationship between GTP synthesis and ppGpp homeostasis, we generated transgenic rice plants over-expressing RSH3, a protein known to act as a ppGpp synthase. When RSH3 was overexpressed in v2, the leaf chlorosis was more severe. Although the RSH3 overexpression in the wild type caused no visible effects, pulse amplitude modulation fluorometer measurements indicated that photosynthetic rates were reduced in this line. This finding implies that the regulation of ppGpp synthesis in rice is involved in the maintenance of the GTP pool required to regulate plastid gene expression during early chloroplast biogenesis. We further investigated changes in the expressions of RelA/SpoT Homolog (RSH) genes encoding ppGpp synthases and hydrolases during the same period. Comparing the expression of these genes with the cellular ppGpp content suggests that the basal ppGpp level is determined by the antagonistic action of multiple RSH enzymatic activities during early leaf development in rice.
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Affiliation(s)
- Kazuhiro Ito
- Department of Biology, Faculty of Science, Kyushu University, Motooka 744, Fukuoka, 819-0395 Japan
| | - Doshun Ito
- Department of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501 Japan
| | - Mina Goto
- Department of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501 Japan
| | - Sae Suzuki
- Department of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501 Japan
| | - Shinji Masuda
- Department of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501 Japan
| | - Koh Iba
- Department of Biology, Faculty of Science, Kyushu University, Motooka 744, Fukuoka, 819-0395 Japan
| | - Kensuke Kusumi
- Department of Biology, Faculty of Science, Kyushu University, Motooka 744, Fukuoka, 819-0395 Japan
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12
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Coordination of Chloroplast Activity with Plant Growth: Clues Point to TOR. PLANTS 2022; 11:plants11060803. [PMID: 35336685 PMCID: PMC8953291 DOI: 10.3390/plants11060803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/14/2022] [Accepted: 03/16/2022] [Indexed: 11/17/2022]
Abstract
Photosynthesis is the defining function of most autotrophic organisms. In the plantae kingdom, chloroplasts host this function and ensure growth. However, these organelles are very sensitive to stressful conditions and the photosynthetic process can cause photooxidative damage if not perfectly regulated. In addition, their function is energivorous in terms of both chemical energy and nutrients. To coordinate chloroplast activity with the cell’s need, continuous signaling is required: from chloroplasts to cytoplasm and from nucleus to chloroplasts. In this opinion article, several mechanisms that ensure this communication are reported and the many clues that point to an important role of the Target of Rapamycin (TOR) kinase in the coordination between the eukaryotic and prokaryotic sides of plants are highlighted.
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13
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Romand S, Abdelkefi H, Lecampion C, Belaroussi M, Dussenne M, Ksas B, Citerne S, Caius J, D'Alessandro S, Fakhfakh H, Caffarri S, Havaux M, Field B. A guanosine tetraphosphate (ppGpp) mediated brake on photosynthesis is required for acclimation to nitrogen limitation in Arabidopsis. eLife 2022; 11:75041. [PMID: 35156611 PMCID: PMC8887892 DOI: 10.7554/elife.75041] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 02/14/2022] [Indexed: 11/13/2022] Open
Abstract
Guanosine pentaphosphate and tetraphosphate (together referred to as ppGpp) are hyperphosphorylated nucleotides found in bacteria and the chloroplasts of plants and algae. In plants and algae artificial ppGpp accumulation can inhibit chloroplast gene expression, and influence photosynthesis, nutrient remobilisation, growth, and immunity. However, it is so far unknown whether ppGpp is required for abiotic stress acclimation in plants. Here, we demonstrate that ppGpp biosynthesis is necessary for acclimation to nitrogen starvation in Arabidopsis. We show that ppGpp is required for remodeling the photosynthetic electron transport chain to downregulate photosynthetic activity and for protection against oxidative stress. Furthermore, we demonstrate that ppGpp is required for coupling chloroplastic and nuclear gene expression during nitrogen starvation. Altogether, our work indicates that ppGpp is a pivotal regulator of chloroplast activity for stress acclimation in plants.
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Affiliation(s)
- Shanna Romand
- LGBP Team, Aix-Marseille University, CEA, CNRS, BIAM, Marseille, France
| | - Hela Abdelkefi
- LGBP Team, Aix-Marseille University, CEA, CNRS, BIAM, Marseille, France
| | - Cécile Lecampion
- LGBP Team, Aix-Marseille University, CEA, CNRS, BIAM, Marseille, France
| | | | - Melanie Dussenne
- LGBP Team, Aix-Marseille University, CEA, CNRS, BIAM, Marseille, France
| | - Brigitte Ksas
- Faculty of Sciences, University of Carthage, Bizerte, Tunisia
| | - Sylvie Citerne
- Institut JeanPierre Bourgin, Université Paris-Saclay, UMR1318, INRAE, Versailles, France
| | - Jose Caius
- Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, CNRS, INRAE, Orsay, France
| | | | - Hatem Fakhfakh
- Laboratory of Molecular Genetics, Immunology and Biotechnology, University of Tunis El Manar, Tunis, Tunisia
| | - Stefano Caffarri
- LGBP Team, Aix-Marseille University, CEA, CNRS, BIAM, Marseille, France
| | - Michel Havaux
- SAVE Team, Aix-Marseille University, CEA, CNRS, BIAM, Saint-Paul-lez-Durance,, France
| | - Benjamin Field
- LGBP Team, Aix-Marseille University, CEA, CNRS, BIAM, Marseille, France
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14
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Li H, Nian J, Fang S, Guo M, Huang X, Zhang F, Wang Q, Zhang J, Bai J, Dong G, Xin P, Xie X, Chen F, Wang G, Wang Y, Qian Q, Zuo J, Chu J, Ma X. Regulation of nitrogen starvation responses by the alarmone (p)ppGpp in rice. J Genet Genomics 2022; 49:469-480. [DOI: 10.1016/j.jgg.2022.02.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 02/14/2022] [Accepted: 02/16/2022] [Indexed: 12/20/2022]
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15
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Goto M, Oikawa A, Masuda S. Metabolic changes contributing to large biomass production in the Arabidopsis ppGpp-accumulating mutant under nitrogen deficiency. PLANTA 2022; 255:48. [PMID: 35079894 DOI: 10.1007/s00425-022-03835-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
The Arabidopsis ppGpp-overproducing mutant indicates a larger biomass than wild type by modulated amino-acid metabolism under nitrogen-limiting conditions. The regulatory nucleotide, guanosine 3', 5'-bis(pyrophosphate; ppGpp)-originally identified in Escherichia coli-controls gene expression and enzyme activities in the bacteria and plastids of plant cells. We recently reported that the ppGpp over-producing mutant of Arabidopsis thaliana had a larger shoot weight than wild type (WT), especially under nutrient-deficient conditions. However, the mechanisms behind the influence of ppGpp on plant growth and biomass remain elusive. To understand the impact of the ppGpp accumulation on plant growth, we characterized metabolic changes in the ppGpp-overproducing mutant upon transition from nitrogen-rich to nitrogen-limiting concentrations. We found that the fresh weight of the mutant was significantly larger than WT when the total nitrogen source (KNO3 and NH4NO3) concentration was below 0.9 mM. When the nitrogen content in the medium decreased, aromatic and branched-chain amino acids increased in WT due to accelerated protein degradation and/or attenuated protein synthesis. These amino-acid levels in the ppGpp over-accumulating mutant decreased upon nitrogen deficiency. The results suggest that the ppGpp-overaccumulation affects amino-acid and protein homeostasis and facilitates growth under nitrogen-limiting conditions.
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Affiliation(s)
- Mina Goto
- Department of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan
| | - Akira Oikawa
- Faculty of Agriculture, Yamagata University, Tsuruoka, 997-8555, Japan
- Present Address: Graduate School of Agriculture, Kyoto University, Uji, 611-0011, Japan
| | - Shinji Masuda
- Department of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan.
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16
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In Silico Study of the RSH ( RelA/ SpoT Homologs) Gene Family and Expression Analysis in Response to PGPR Bacteria and Salinity in Brassica napus. Int J Mol Sci 2021; 22:ijms221910666. [PMID: 34639007 PMCID: PMC8509286 DOI: 10.3390/ijms221910666] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/21/2021] [Accepted: 09/28/2021] [Indexed: 12/21/2022] Open
Abstract
Among several mechanisms involved in the plant stress response, synthesis of guanosine tetra and pentaphosphates (alarmones), homologous to the bacterial stringent response, is of crucial importance. Plant alarmones affect, among others, photosynthetic activity, metabolite accumulation, and nutrient remobilization, and thus regulate plant growth and development. The plant RSH (RelA/SpoT homolog) genes, that encode synthetases and/or hydrolases of alarmones, have been characterized in a limited number of plant species, e.g., Arabidopsis thaliana, Oryza sativa, and Ipomoea nil. Here, we used dry-to-wet laboratory research approaches to characterize RSH family genes in the polyploid plant Brassica napus. There are 12 RSH genes in the genome of rapeseed that belong to four types of RSH genes: 6 RSH1, 2 RSH2, 3 RSH3, and 1 CRSH. BnRSH genes contain 13-24 introns in RSH1, 2-6 introns in RSH2, 1-6 introns in RSH3, and 2-3 introns in the CRSH genes. In the promoter regions of the RSH genes, we showed the presence of regulatory elements of the response to light, plant hormones, plant development, and abiotic and biotic stresses. The wet-lab analysis showed that expression of BnRSH genes is generally not significantly affected by salt stress, but that the presence of PGPR bacteria, mostly of Serratia sp., increased the expression of BnRSH significantly. The obtained results show that BnRSH genes are differently affected by biotic and abiotic factors, which indicates their different functions in plants.
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17
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Petrova O, Parfirova O, Gogolev Y, Gorshkov V. Stringent Response in Bacteria and Plants with Infection. PHYTOPATHOLOGY 2021; 111:1811-1817. [PMID: 34296953 DOI: 10.1094/phyto-11-20-0510-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Stringent response (SR), a primary stress reaction in bacteria and plant chloroplasts, is a molecular switch that provides operational stress-induced reprogramming of transcription under conditions of abiotic and biotic stress. Because the infection is a stressful situation for both partners (the host plant and the pathogen), we analyzed the expression of bacterial and plastid SR-related genes during plant-microbial interaction. In the phytopathogenic bacterium Pectobacterium atrosepticum, SpoT-dependent SR was induced after contact with potato or tobacco plants. In plants, two different scenarios of molecular events developed under bacterial infection. Plastid SR was not induced in the host plant potato Solanum tuberosum, which co-evolved with the pathogen for a long time. In this case, the salicylic acid defense pathway was activated and plants were more resistant to bacterial infection. SR was activated in the tobacco Nicotiana tabacum (experimental host) along with activation of jasmonic acid-related genes, resulting in plant death. These results are important to more fully understand the evolutionary interactions between plants and symbionts/pathogens.
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Affiliation(s)
- Olga Petrova
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center, Kazan Scientific Center of Russian Academy of Sciences, Kazan 420111, Russian Federation
| | - Olga Parfirova
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center, Kazan Scientific Center of Russian Academy of Sciences, Kazan 420111, Russian Federation
| | - Yuri Gogolev
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center, Kazan Scientific Center of Russian Academy of Sciences, Kazan 420111, Russian Federation
| | - Vladimir Gorshkov
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center, Kazan Scientific Center of Russian Academy of Sciences, Kazan 420111, Russian Federation
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18
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Mojr V, Roghanian M, Tamman H, Do Pham DD, Petrová M, Pohl R, Takada H, Van Nerom K, Ainelo H, Caballero-Montes J, Jimmy S, Garcia-Pino A, Hauryliuk V, Rejman D. Nonhydrolysable Analogues of (p)ppGpp and (p)ppApp Alarmone Nucleotides as Novel Molecular Tools. ACS Chem Biol 2021; 16:1680-1691. [PMID: 34477366 DOI: 10.1021/acschembio.1c00398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
While alarmone nucleotides guanosine-3',5'-bisdiphosphate (ppGpp) and guanosine-5'-triphosphate-3'-diphosphate (pppGpp) are archetypical bacterial second messengers, their adenosine analogues ppApp (adenosine-3',5'-bisdiphosphate) and pppApp (adenosine-5'-triphosphate-3'-diphosphate) are toxic effectors that abrogate bacterial growth. The alarmones are both synthesized and degraded by the members of the RelA-SpoT Homologue (RSH) enzyme family. Because of the chemical and enzymatic liability of (p)ppGpp and (p)ppApp, these alarmones are prone to degradation during structural biology experiments. To overcome this limitation, we have established an efficient and straightforward procedure for synthesizing nonhydrolysable (p)ppNuNpp analogues starting from 3'-azido-3'-deoxyribonucleotides as key intermediates. To demonstrate the utility of (p)ppGNpp as a molecular tool, we show that (i) as an HD substrate mimic, ppGNpp competes with ppGpp to inhibit the enzymatic activity of human MESH1 Small Alarmone Hyrolase, SAH; and (ii) mimicking the allosteric effects of (p)ppGpp, (p)ppGNpp acts as a positive regulator of the synthetase activity of long ribosome-associated RSHs Rel and RelA. Finally, by solving the structure of the N-terminal domain region (NTD) of T. thermophilus Rel complexed with pppGNpp, we show that as an HD substrate mimic, the analogue serves as a bona fide orthosteric regulator that promotes the same intra-NTD structural rearrangements as the native substrate.
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Affiliation(s)
- Viktor Mojr
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
| | - Mohammad Roghanian
- Laboratory for Molecular Infection Medicine Sweden (MIMS) and Umea° Centre for Microbial Research (UCMR), Umeå University, 901 87 Umeå, Sweden
- Department of Clinical Microbiology, Rigshospitalet, 2200 Copenhagen, Denmark
| | - Hedvig Tamman
- Cellular and Molecular Microbiology, Faculté des Sciences, Université libre de Bruxelles, Campus La Plaine, Building BC, (1C4 203), Boulevard du Triomphe, 1050, Brussels, Belgium
- WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium
| | - Duy Dinh Do Pham
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
| | - Magdalena Petrová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
| | - Radek Pohl
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
| | - Hiraku Takada
- Laboratory for Molecular Infection Medicine Sweden (MIMS) and Umea° Centre for Microbial Research (UCMR), Umeå University, 901 87 Umeå, Sweden
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo, Motoyama, Kita-ku, Kyoto 603-8555, Japan
| | - Katleen Van Nerom
- Cellular and Molecular Microbiology, Faculté des Sciences, Université libre de Bruxelles, Campus La Plaine, Building BC, (1C4 203), Boulevard du Triomphe, 1050, Brussels, Belgium
- WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium
| | - Hanna Ainelo
- Cellular and Molecular Microbiology, Faculté des Sciences, Université libre de Bruxelles, Campus La Plaine, Building BC, (1C4 203), Boulevard du Triomphe, 1050, Brussels, Belgium
- WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium
| | - Julien Caballero-Montes
- Cellular and Molecular Microbiology, Faculté des Sciences, Université libre de Bruxelles, Campus La Plaine, Building BC, (1C4 203), Boulevard du Triomphe, 1050, Brussels, Belgium
- WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium
| | - Steffi Jimmy
- Laboratory for Molecular Infection Medicine Sweden (MIMS) and Umea° Centre for Microbial Research (UCMR), Umeå University, 901 87 Umeå, Sweden
- Deutsches Elektronen-Synchrotron DESY, Centre for Structural Systems Biology (CSSB), Notkestr. 85, 22607 Hamburg, Germany
| | - Abel Garcia-Pino
- Cellular and Molecular Microbiology, Faculté des Sciences, Université libre de Bruxelles, Campus La Plaine, Building BC, (1C4 203), Boulevard du Triomphe, 1050, Brussels, Belgium
- WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium
| | - Vasili Hauryliuk
- Laboratory for Molecular Infection Medicine Sweden (MIMS) and Umea° Centre for Microbial Research (UCMR), Umeå University, 901 87 Umeå, Sweden
- University of Tartu, Institute of Technology, 50411 Tartu, Estonia
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
| | - Dominik Rejman
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
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19
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Avilan L, Lebrun R, Puppo C, Citerne S, Cuiné S, Li‐Beisson Y, Menand B, Field B, Gontero B. ppGpp influences protein protection, growth and photosynthesis in Phaeodactylum tricornutum. THE NEW PHYTOLOGIST 2021; 230:1517-1532. [PMID: 33595847 PMCID: PMC8252717 DOI: 10.1111/nph.17286] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 02/08/2021] [Indexed: 05/08/2023]
Abstract
Chloroplasts retain elements of a bacterial stress response pathway that is mediated by the signalling nucleotides guanosine penta- and tetraphosphate ((p)ppGpp). In the model flowering plant Arabidopsis, ppGpp acts as a potent regulator of plastid gene expression and influences photosynthesis, plant growth and development. However, little is known about ppGpp metabolism or its evolution in other photosynthetic eukaryotes. Here, we studied the function of ppGpp in the diatom Phaeodactylum tricornutum using transgenic lines containing an inducible system for ppGpp accumulation. We used these lines to investigate the effects of ppGpp on growth, photosynthesis, lipid metabolism and protein expression. We demonstrate that ppGpp accumulation reduces photosynthetic capacity and promotes a quiescent-like state with reduced proliferation and ageing. Strikingly, using nontargeted proteomics, we discovered that ppGpp accumulation also leads to the coordinated upregulation of a protein protection response in multiple cellular compartments. Our findings highlight the importance of ppGpp as a fundamental regulator of chloroplast function across different domains of life, and lead to new questions about the molecular mechanisms and roles of (p)ppGpp signalling in photosynthetic eukaryotes.
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Affiliation(s)
- Luisana Avilan
- CNRSBIPUMR 7281IMM FR 3479Aix Marseille Univ31 Chemin Joseph AiguierMarseille13009France
- Centre for Enzyme InnovationSchool of Biological SciencesInstitute of Biological and Biomedical SciencesUniversity of PortsmouthPortsmouthPO1 2DYUK
| | - Regine Lebrun
- Plate‐forme ProtéomiqueMarseille Protéomique (MaP)IMM FR 3479, 31 Chemin Joseph AiguierMarseille13009France
| | - Carine Puppo
- CNRSBIPUMR 7281IMM FR 3479Aix Marseille Univ31 Chemin Joseph AiguierMarseille13009France
| | - Sylvie Citerne
- Institut Jean‐Pierre BourginINRAEAgroParisTechUniversité Paris‐SaclayVersailles78000France
| | - Stephane Cuiné
- CEA, CNRS, UMR7265 BIAMCEA CadaracheAix‐Marseille UnivSaint‐Paul‐lez Durance13108France
| | - Yonghua Li‐Beisson
- CEA, CNRS, UMR7265 BIAMCEA CadaracheAix‐Marseille UnivSaint‐Paul‐lez Durance13108France
| | - Benoît Menand
- CEA, CNRS, UMR7265 BIAMAix‐Marseille UnivMarseille13009France
| | - Ben Field
- CEA, CNRS, UMR7265 BIAMAix‐Marseille UnivMarseille13009France
| | - Brigitte Gontero
- CNRSBIPUMR 7281IMM FR 3479Aix Marseille Univ31 Chemin Joseph AiguierMarseille13009France
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20
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Freudenberg RA, Baier T, Einhaus A, Wobbe L, Kruse O. High cell density cultivation enables efficient and sustainable recombinant polyamine production in the microalga Chlamydomonas reinhardtii. BIORESOURCE TECHNOLOGY 2021; 323:124542. [PMID: 33385626 DOI: 10.1016/j.biortech.2020.124542] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 05/27/2023]
Abstract
Modern chemical industry calls for new resource-efficient and sustainable value chains for production of key base chemicals such as polyamines. The green microalga Chlamydomonas reinhardtii offers great potential as an innovative green-cell factory by combining fast and inexpensive, phototrophic growth with mature genetic engineering. Here, overexpression of recombinant lysine decarboxylases in C. reinhardtii enabled the robust accumulation of the non-native polyamine cadaverine, which serves as building block for bio-polyamides. The issue of low cell densities, limiting most microalgal cultivation processes was resolved by systematically optimizing cultivation parameters. A new, easy-to-apply and fully phototrophic medium enables high cell density cultivations of C. reinhardtii with a 6-fold increase in biomass and cell count (20 g/L biomass dry weight, ~2·108 cells/mL). Application of high cell density cultivations in established photobioreactors resulted in a 10-fold increase of cadaverine yields, with up to 0.24 g/L after 9 days and maximal productivity of 0.1 g/L/d.
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Affiliation(s)
- Robert A Freudenberg
- Bielefeld University, Faculty of Biology, Center for Biotechnology (CeBiTec), Universitätsstrasse 27, 33615 Bielefeld, Germany
| | - Thomas Baier
- Bielefeld University, Faculty of Biology, Center for Biotechnology (CeBiTec), Universitätsstrasse 27, 33615 Bielefeld, Germany
| | - Alexander Einhaus
- Bielefeld University, Faculty of Biology, Center for Biotechnology (CeBiTec), Universitätsstrasse 27, 33615 Bielefeld, Germany
| | - Lutz Wobbe
- Bielefeld University, Faculty of Biology, Center for Biotechnology (CeBiTec), Universitätsstrasse 27, 33615 Bielefeld, Germany
| | - Olaf Kruse
- Bielefeld University, Faculty of Biology, Center for Biotechnology (CeBiTec), Universitätsstrasse 27, 33615 Bielefeld, Germany.
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21
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Ono S, Suzuki S, Ito D, Tagawa S, Shiina T, Masuda S. Plastidial (p)ppGpp Synthesis by the Ca2+-Dependent RelA-SpoT Homolog Regulates the Adaptation of Chloroplast Gene Expression to Darkness in Arabidopsis. PLANT & CELL PHYSIOLOGY 2021; 61:2077-2086. [PMID: 33089303 DOI: 10.1093/pcp/pcaa124] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 09/15/2020] [Indexed: 06/11/2023]
Abstract
In bacteria, the hyper-phosphorylated nucleotide, guanosine 3',5'-bis(pyrophosphate) (ppGpp), functions as a secondary messenger under stringent conditions. ppGpp levels are controlled by two distinct enzymes, namely RelA and SpoT, in Escherichia coli. RelA-SpoT homologs (RSHs) are also conserved in plants where they function in the plastids. The model plant Arabidopsis thaliana contains four RSHs: RSH1, RSH2, RSH3 and Ca2+-dependent RSH (CRSH). Genetic characterizations of RSH1, RSH2 and RSH3 were undertaken, which showed that the ppGpp-dependent plastidial stringent response significantly influences plant growth and stress acclimation. However, the physiological significance of CRSH-dependent ppGpp synthesis remains unclear, as no crsh-null mutant has been available. Here, to investigate the function of CRSH, a crsh-knockout mutant of Arabidopsis was constructed using a site-specific gene-editing technique, and its phenotype was characterized. A transient increase in ppGpp was observed for 30 min in the wild type (WT) after the light-to-dark transition, but this increase was not observed in the crsh mutant. Similar analyses were performed with the rsh2-rsh3 double and rsh1-rsh2-rsh3 triple mutants and showed that the transient increments of ppGpp in the mutants were higher than those in the WT. The increase in ppGpp in the WT and rsh2 rsh3 accompanied decrements in the mRNA levels of some plastidial genes transcribed by the plastid-encoded plastid RNA polymerase. These results indicate that the transient increase in ppGpp at night is due to CRSH-dependent ppGpp synthesis and that the ppGpp level is maintained by the hydrolytic activities of RSH1, RSH2 and RSH3 to accustom plastidial gene expression to darkness.
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Affiliation(s)
- Sumire Ono
- Graduate School of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Sae Suzuki
- Graduate School of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Doshun Ito
- Graduate School of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Shota Tagawa
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Sakyo-ku, Kyoto, 606-8522 Japan
| | - Takashi Shiina
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Sakyo-ku, Kyoto, 606-8522 Japan
| | - Shinji Masuda
- Graduate School of Life Science & Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
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Kurkela J, Fredman J, Salminen TA, Tyystjärvi T. Revealing secrets of the enigmatic omega subunit of bacterial RNA polymerase. Mol Microbiol 2021; 115:1-11. [PMID: 32920946 DOI: 10.1111/mmi.14603] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/03/2020] [Accepted: 09/04/2020] [Indexed: 12/14/2022]
Abstract
The conserved omega (ω) subunit of RNA polymerase (RNAP) is the only nonessential subunit of bacterial RNAP core. The small ω subunit (7 kDa-11.5 kDa) contains three conserved α helices, and helices α2 and α3 contain five fully conserved amino acids of ω. Four conserved amino acids stabilize the correct folding of the ω subunit and one is located in the vicinity of the β' subunit of RNAP. Otherwise ω shows high variation between bacterial taxa, and although the main interaction partner of ω is always β', many interactions are taxon-specific. ω-less strains show pleiotropic phenotypes, and based on in vivo and in vitro results, a few roles for the ω subunits have been described. Interactions of the ω subunit with the β' subunit are important for the RNAP core assembly and integrity. In addition, the ω subunit plays a role in promoter selection, as ω-less RNAP cores recruit fewer primary σ factors and more alternative σ factors than intact RNAP cores in many species. Furthermore, the promoter selection of an ω-less RNAP holoenzyme bearing the primary σ factor seems to differ from that of an intact RNAP holoenzyme.
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Affiliation(s)
- Juha Kurkela
- Department of Biochemistry/Molecular Plant Biology, University of Turku, Turku, Finland
| | - Julia Fredman
- Faculty of Science and Engineering/Biochemistry/Structural Bioinformatics Laboratory, Åbo Akademi University, Turku, Finland
| | - Tiina A Salminen
- Faculty of Science and Engineering/Biochemistry/Structural Bioinformatics Laboratory, Åbo Akademi University, Turku, Finland
| | - Taina Tyystjärvi
- Department of Biochemistry/Molecular Plant Biology, University of Turku, Turku, Finland
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23
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Quantification of guanosine triphosphate and tetraphosphate in plants and algae using stable isotope-labelled internal standards. Talanta 2020; 219:121261. [PMID: 32887152 DOI: 10.1016/j.talanta.2020.121261] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 06/03/2020] [Indexed: 12/20/2022]
Abstract
Guanosine tetraphosphate (G4P) and guanosine pentaphosphate (G5P) are signalling nucleotides found in bacteria and photosynthetic eukaryotes that are implicated in a wide-range of processes including stress acclimation, developmental transitions and growth control. Measurements of G4P/G5P levels are essential for studying the diverse roles of these nucleotides. However, G4P/G5P quantification is particularly challenging in plants and algae due to lower cellular concentrations, compartmentalization and high metabolic complexity. Despite recent advances the speed and accuracy of G4P quantification in plants and algae can still be improved. Here, we report a new approach for rapid and accurate G4P quantification which relies on the use of synthesized stable isotope-labelled as internal standards. We anticipate that this approach will accelerate research into the function of G4P signaling in plants, algae and other organisms.
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24
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Tadini L, Jeran N, Peracchio C, Masiero S, Colombo M, Pesaresi P. The plastid transcription machinery and its coordination with the expression of nuclear genome: Plastid-Encoded Polymerase, Nuclear-Encoded Polymerase and the Genomes Uncoupled 1-mediated retrograde communication. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190399. [PMID: 32362266 DOI: 10.1098/rstb.2019.0399] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Plastid genes in higher plants are transcribed by at least two different RNA polymerases, the plastid-encoded RNA polymerase (PEP), a bacteria-like core enzyme whose subunits are encoded by plastid genes (rpoA, rpoB, rpoC1 and rpoC2), and the nuclear-encoded plastid RNA polymerase (NEP), a monomeric bacteriophage-type RNA polymerase. Both PEP and NEP enzymes are active in non-green plastids and in chloroplasts at all developmental stages. Their transcriptional activity is affected by endogenous and exogenous factors and requires a strict coordination within the plastid and with the nuclear gene expression machinery. This review focuses on the different molecular mechanisms underlying chloroplast transcription regulation and its coordination with the photosynthesis-associated nuclear genes (PhANGs) expression. Particular attention is given to the link between NEP and PEP activity and the GUN1- (Genomes Uncoupled 1) mediated chloroplast-to-nucleus retrograde communication with respect to the Δrpo adaptive response, i.e. the increased accumulation of NEP-dependent transcripts upon depletion of PEP activity, and the editing-level changes observed in NEP-dependent transcripts, including rpoB and rpoC1, in gun1 cotyledons after norflurazon or lincomycin treatment. The role of cytosolic preproteins and HSP90 chaperone as components of the GUN1-retrograde signalling pathway, when chloroplast biogenesis is inhibited in Arabidopsis cotyledons, is also discussed. This article is part of the theme issue 'Retrograde signalling from endosymbiotic organelles'.
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Affiliation(s)
- Luca Tadini
- Dipartimento di Bioscienze, Università degli studi di Milano, 20133 Milano, Italy
| | - Nicolaj Jeran
- Dipartimento di Bioscienze, Università degli studi di Milano, 20133 Milano, Italy
| | - Carlotta Peracchio
- Dipartimento di Bioscienze, Università degli studi di Milano, 20133 Milano, Italy
| | - Simona Masiero
- Dipartimento di Bioscienze, Università degli studi di Milano, 20133 Milano, Italy
| | - Monica Colombo
- Centro Ricerca e Innovazione, Fondazione Edmund Mach, 38010 San Michele all'Adige, Italy
| | - Paolo Pesaresi
- Dipartimento di Bioscienze, Università degli studi di Milano, 20133 Milano, Italy
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25
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Trösch R, Willmund F. The conserved theme of ribosome hibernation: from bacteria to chloroplasts of plants. Biol Chem 2020; 400:879-893. [PMID: 30653464 DOI: 10.1515/hsz-2018-0436] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 01/03/2019] [Indexed: 12/21/2022]
Abstract
Cells are highly adaptive systems that respond and adapt to changing environmental conditions such as temperature fluctuations or altered nutrient availability. Such acclimation processes involve reprogramming of the cellular gene expression profile, tuning of protein synthesis, remodeling of metabolic pathways and morphological changes of the cell shape. Nutrient starvation can lead to limited energy supply and consequently, remodeling of protein synthesis is one of the key steps of regulation since the translation of the genetic code into functional polypeptides may consume up to 40% of a cell's energy during proliferation. In eukaryotic cells, downregulation of protein synthesis during stress is mainly mediated by modification of the translation initiation factors. Prokaryotic cells suppress protein synthesis by the active formation of dimeric so-called 'hibernating' 100S ribosome complexes. Such a transition involves a number of proteins which are found in various forms in prokaryotes but also in chloroplasts of plants. Here, we review the current understanding of these hibernation factors and elaborate conserved principles which are shared between species.
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Affiliation(s)
- Raphael Trösch
- Department of Biology, Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Straße 23, D-67663 Kaiserslautern, Germany
| | - Felix Willmund
- Department of Biology, Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Straße 23, D-67663 Kaiserslautern, Germany
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26
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RSH enzyme diversity for (p)ppGpp metabolism in Phaeodactylum tricornutum and other diatoms. Sci Rep 2019; 9:17682. [PMID: 31776430 PMCID: PMC6881373 DOI: 10.1038/s41598-019-54207-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 11/05/2019] [Indexed: 12/28/2022] Open
Abstract
The nucleotides guanosine tetraphosphate and pentaphosphate (together known as (p)ppGpp or magic spot) are produced in plant plastids from GDP/GTP and ATP by RelA-SpoT homologue (RSH) enzymes. In the model plant Arabidopsis (p)ppGpp regulates chloroplast transcription and translation to affect growth, and is also implicated in acclimation to stress. However, little is known about (p)ppGpp metabolism or its evolution in other photosynthetic eukaryotes. Here we studied (p)ppGpp metabolism in the marine diatom Phaeodactylum tricornutum. We identified three expressed RSH genes in the P. tricornutum genome, and determined the enzymatic activity of the corresponding enzymes by heterologous expression in bacteria. We showed that two P. tricornutum RSH are (p)ppGpp synthetases, despite substitution of a residue within the active site believed critical for activity, and that the third RSH is a bifunctional (p)ppGpp synthetase and hydrolase, the first of its kind demonstrated in a photosynthetic eukaryote. A broad phylogenetic analysis then showed that diatom RSH belong to novel algal RSH clades. Together our work significantly expands the horizons of (p)ppGpp signalling in the photosynthetic eukaryotes by demonstrating an unexpected functional, structural and evolutionary diversity in RSH enzymes from organisms with plastids derived from red algae.
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27
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Prusińska JM, Boniecka J, Dąbrowska GB, Goc A. Identification and characterization of the Ipomoea nil RelA/SpoT Homologs (InRSHs) and potential directions of their transcriptional regulation. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 284:161-176. [PMID: 31084869 DOI: 10.1016/j.plantsci.2019.01.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 01/13/2019] [Accepted: 01/30/2019] [Indexed: 06/09/2023]
Abstract
Although the stringent response has been known for more than half a century and has been well studied in bacteria, only the research of the past 19 years revealed that the homologous mechanism is conserved in plants. The plant RelA/SpoT Homolog (RSH) genes have been identified and characterized in a limited number of plant species, whereas products of their catalytic activities, (p)ppGpp (alarmones), have been shown to accumulate mainly in chloroplasts. Here, we identified full-length sequences of the Ipomoea nil RSH genes (InRSH1, InRSH2 and InCRSH), determined their copy number in the I. nil genome as well as the structural conservancy between InRSHs and their Arabidopsis and rice orthologs. We showed that InRSHs are differentially expressed in I. nil organ tissues and that only InRSH2 is upregulated in response to salt, osmotic and drought stress. Our results of the E. coli relA/spoT mutant complementation test suggest that InRSH1 is likely a (p)ppGpp hydrolase, InCRSH - synthetase and InRSH2 shows both activities. Finally, we referred our results to the recently published I. nil genomic and proteomic data and uncovered the complexity of the I. nil RSH family as well as potential ways of the InRSH transcriptional regulation.
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Affiliation(s)
- Justyna M Prusińska
- Nicolaus Copernicus University in Toruń, Department of Genetics, Lwowska 1, 87-100, Toruń, Poland.
| | - Justyna Boniecka
- Nicolaus Copernicus University in Toruń, Department of Genetics, Lwowska 1, 87-100, Toruń, Poland
| | - Grażyna B Dąbrowska
- Nicolaus Copernicus University in Toruń, Department of Genetics, Lwowska 1, 87-100, Toruń, Poland
| | - Anna Goc
- Nicolaus Copernicus University in Toruń, Department of Genetics, Lwowska 1, 87-100, Toruń, Poland
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28
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Sobala M, Bruhn-Olszewska B, Cashel M, Potrykus K. Methylobacterium extorquens RSH Enzyme Synthesizes (p)ppGpp and pppApp in vitro and in vivo, and Leads to Discovery of pppApp Synthesis in Escherichia coli. Front Microbiol 2019; 10:859. [PMID: 31068922 PMCID: PMC6491832 DOI: 10.3389/fmicb.2019.00859] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 04/03/2019] [Indexed: 01/12/2023] Open
Abstract
In bacteria, the so-called stringent response is responsible for adaptation to changing environmental conditions. This response is mediated by guanosine derivatives [(p)ppGpp], synthesized by either large mono-functional RelA or bi-functional SpoT (synthesis and hydrolysis) enzymes in β- and γ-proteobacteria, such as Escherichia coli. In Firmicutes and α-, δ-, and 𝜀-proteobacteria, large bifunctional Rel-SpoT-homologs (RSH), often accompanied by small (p)ppGpp synthetases and/or hydrolases devoid of regulatory domains, are responsible for (p)ppGpp turnover. Here, we report on surprising in vitro and in vivo properties of an RSH enzyme from Methylobacterium extorquens (RSHMex). We find that this enzyme possesses some unique features, e.g., it requires cobalt cations for the most efficient (p)ppGpp synthesis, in contrast to all other known specific (p)ppGpp synthetases that require Mg2+. In addition, it can synthesize pppApp, which has not been demonstrated in vitro for any Rel/SpoT/RSH enzyme so far. In vivo, our studies also show that RSHMex is active in Escherichia coli cells, as it can complement E. coli ppGpp0 growth defects and affects rrnB P1-lacZ fusion activity in a way expected for an RSH enzyme. These studies also led us to discover pppApp synthesis in wild type E. coli cells (not carrying the RSHMex enzyme), which to our knowledge has not been demonstrated ever before. In the light of our recent discovery that pppApp directly regulates E. coli RNAP transcription in vitro in a manner opposite to (p)ppGpp, this leads to a possibility that pppApp is a new member of the nucleotide second-messenger family that is widely present in bacterial species.
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Affiliation(s)
- Michał Sobala
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Bożena Bruhn-Olszewska
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Michael Cashel
- Intramural Program, Eunice Kennedy Shriver Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Katarzyna Potrykus
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
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29
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The Significance of Calcium in Photosynthesis. Int J Mol Sci 2019; 20:ijms20061353. [PMID: 30889814 PMCID: PMC6471148 DOI: 10.3390/ijms20061353] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 02/23/2019] [Accepted: 03/01/2019] [Indexed: 01/12/2023] Open
Abstract
As a secondary messenger, calcium participates in various physiological and biochemical reactions in plants. Photosynthesis is the most extensive biosynthesis process on Earth. To date, researchers have found that some chloroplast proteins have Ca2+-binding sites, and the structure and function of some of these proteins have been discussed in detail. Although the roles of Ca2+ signal transduction related to photosynthesis have been discussed, the relationship between calcium and photosynthesis is seldom systematically summarized. In this review, we provide an overview of current knowledge of calcium’s role in photosynthesis.
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30
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Lu Y, Yao J. Chloroplasts at the Crossroad of Photosynthesis, Pathogen Infection and Plant Defense. Int J Mol Sci 2018; 19:E3900. [PMID: 30563149 PMCID: PMC6321325 DOI: 10.3390/ijms19123900] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 11/30/2018] [Accepted: 12/03/2018] [Indexed: 12/31/2022] Open
Abstract
Photosynthesis, pathogen infection, and plant defense are three important biological processes that have been investigated separately for decades. Photosynthesis generates ATP, NADPH, and carbohydrates. These resources are utilized for the synthesis of many important compounds, such as primary metabolites, defense-related hormones abscisic acid, ethylene, jasmonic acid, and salicylic acid, and antimicrobial compounds. In plants and algae, photosynthesis and key steps in the synthesis of defense-related hormones occur in chloroplasts. In addition, chloroplasts are major generators of reactive oxygen species and nitric oxide, and a site for calcium signaling. These signaling molecules are essential to plant defense as well. All plants grown naturally are attacked by pathogens. Bacterial pathogens enter host tissues through natural openings or wounds. Upon invasion, bacterial pathogens utilize a combination of different virulence factors to suppress host defense and promote pathogenicity. On the other hand, plants have developed elaborate defense mechanisms to protect themselves from pathogen infections. This review summarizes recent discoveries on defensive roles of signaling molecules made by plants (primarily in their chloroplasts), counteracting roles of chloroplast-targeted effectors and phytotoxins elicited by bacterial pathogens, and how all these molecules crosstalk and regulate photosynthesis, pathogen infection, and plant defense, using chloroplasts as a major battlefield.
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Affiliation(s)
- Yan Lu
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI 49008, USA.
| | - Jian Yao
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI 49008, USA.
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31
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Patacq C, Chaudet N, Létisse F. Absolute Quantification of ppGpp and pppGpp by Double-Spike Isotope Dilution Ion Chromatography-High-Resolution Mass Spectrometry. Anal Chem 2018; 90:10715-10723. [PMID: 30110552 DOI: 10.1021/acs.analchem.8b00829] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Guanosine 5'-diphosphate 3'-diphosphate (ppGpp) and guanosine 5'-triphosphate 3'-diphosphate (pppGpp) play a central role in the adaptation of bacterial and plant cells to nutritional and environmental stresses and in bacterial resistance to antibiotics. These compounds have historically been detected and quantified by two-dimensional thin-layer chromatography of 32P-radiolabeled nucleotides. We report a new method to quantify ppGpp and pppGpp in complex biochemical matrix using ion chromatography coupled to high-resolution mass spectrometry. The method is based on isotopic dilution mass spectrometry (IDMS) using 13C to accurately quantify the nucleotides. However, the loss of a phosphate group from pppGpp during the sample preparation process results in the erroneous quantification of ppGpp. This bias was corrected by adding an extra 15N isotope dilution dimension. This double-spike IDMS method was applied to quantify the ppGpp and pppGpp in Escherichia coli and in a mutant strain deleted for gppA (encoding the ppGpp phosphohydrolase) before and after exposure of both strains to serine hydroxamate, known to trigger the accumulation of these nucleotides.
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Affiliation(s)
- Clément Patacq
- Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés, Université de Toulouse , CNRS, INRA, INSA, 31077 Toulouse , France.,Département de Bioprocédés R&D , Sanofi Pasteur , 69280 Marcy-L'Etoile , France
| | - Nicolas Chaudet
- Département de Bioprocédés R&D , Sanofi Pasteur , 69280 Marcy-L'Etoile , France
| | - Fabien Létisse
- Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés, Université de Toulouse , CNRS, INRA, INSA, 31077 Toulouse , France.,Université Paul Sabatier, Université de Toulouse , 31330 Toulouse , France
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32
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Hsieh PH, Kan CC, Wu HY, Yang HC, Hsieh MH. Early molecular events associated with nitrogen deficiency in rice seedling roots. Sci Rep 2018; 8:12207. [PMID: 30111825 PMCID: PMC6093901 DOI: 10.1038/s41598-018-30632-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 07/31/2018] [Indexed: 11/16/2022] Open
Abstract
Nitrogen (N) deficiency is one of the most common problems in rice. The symptoms of N deficiency are well documented, but the underlying molecular mechanisms are largely unknown in rice. Here, we studied the early molecular events associated with N starvation (−N, 1 h), focusing on amino acid analysis and identification of −N-regulated genes in rice roots. Interestingly, levels of glutamine rapidly decreased within 15 min of −N treatment, indicating that part of the N-deficient signals could be mediated by glutamine. Transcriptome analysis revealed that genes involved in metabolism, plant hormone signal transduction (e.g. abscisic acid, auxin, and jasmonate), transporter activity, and oxidative stress responses were rapidly regulated by −N. Some of the −N-regulated genes encode transcription factors, protein kinases and protein phosphatases, which may be involved in the regulation of early −N responses in rice roots. Previously, we used similar approaches to identify glutamine-, glutamate-, and ammonium nitrate-responsive genes. Comparisons of the genes induced by different forms of N with the −N-regulated genes identified here have provided a catalog of potential N regulatory genes for further dissection of the N signaling pathwys in rice.
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Affiliation(s)
- Ping-Han Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Chia-Cheng Kan
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Hsin-Yu Wu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Hsiu-Chun Yang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Ming-Hsiun Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan.
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33
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Bechtold U, Field B. Molecular mechanisms controlling plant growth during abiotic stress. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:2753-2758. [PMID: 29788471 PMCID: PMC5961130 DOI: 10.1093/jxb/ery157] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Affiliation(s)
- Ulrike Bechtold
- School of Biological Sciences, University of Essex, Colchester UK
- Correspondence: or
| | - Benjamin Field
- Aix Marseille Univ, CEA, CNRS, UMR7265 BVME, Marseille, France
- Correspondence: or
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34
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Zoschke R, Bock R. Chloroplast Translation: Structural and Functional Organization, Operational Control, and Regulation. THE PLANT CELL 2018; 30:745-770. [PMID: 29610211 PMCID: PMC5969280 DOI: 10.1105/tpc.18.00016] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 03/26/2018] [Accepted: 04/01/2018] [Indexed: 05/20/2023]
Abstract
Chloroplast translation is essential for cellular viability and plant development. Its positioning at the intersection of organellar RNA and protein metabolism makes it a unique point for the regulation of gene expression in response to internal and external cues. Recently obtained high-resolution structures of plastid ribosomes, the development of approaches allowing genome-wide analyses of chloroplast translation (i.e., ribosome profiling), and the discovery of RNA binding proteins involved in the control of translational activity have greatly increased our understanding of the chloroplast translation process and its regulation. In this review, we provide an overview of the current knowledge of the chloroplast translation machinery, its structure, organization, and function. In addition, we summarize the techniques that are currently available to study chloroplast translation and describe how translational activity is controlled and which cis-elements and trans-factors are involved. Finally, we discuss how translational control contributes to the regulation of chloroplast gene expression in response to developmental, environmental, and physiological cues. We also illustrate the commonalities and the differences between the chloroplast and bacterial translation machineries and the mechanisms of protein biosynthesis in these two prokaryotic systems.
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Affiliation(s)
- Reimo Zoschke
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Ralph Bock
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
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