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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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2
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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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Suzuki K, Inoue H, Matsuoka S, Tero R, Hirano-Iwata A, Tozawa Y. Establishment of a cell-free translation system from rice callus extracts. Biosci Biotechnol Biochem 2020; 84:2028-2036. [PMID: 32543982 DOI: 10.1080/09168451.2020.1779024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Eukaryotic in vitro translation systems require large numbers of protein and RNA components and thereby rely on the use of cell extracts. Here we established a new in vitro translation system based on rice callus extract (RCE). We confirmed that RCE maintains its initial activity even after five freeze-thaw cycles and that the optimum temperature for translation is around 20°C. We demonstrated that the RCE system allows the synthesis of hERG, a large membrane protein, in the presence of liposomes. We also showed that the introduction of a bicistronic mRNA based on 2A peptide to RCE allowed the production of two distinct proteins from a single mRNA. Our new method thus facilitates laboratory-scale production of cell extracts, making it a useful tool for the in vitro synthesis of proteins for biochemical studies.
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Affiliation(s)
- Kakeru Suzuki
- Graduate School of Science and Engineering, Saitama University , Saitama, Japan
| | - Haruka Inoue
- Graduate School of Science and Engineering, Saitama University , Saitama, Japan
| | - Satoshi Matsuoka
- Graduate School of Science and Engineering, Saitama University , Saitama, Japan
| | - Ryugo Tero
- Department of Applied Chemistry and Life Science, Toyohashi University of Technology , Toyohashi, Japan
| | - Ayumi Hirano-Iwata
- Advanced Institute for Materials Research, Tohoku University , Sendai, Japan
| | - Yuzuru Tozawa
- Graduate School of Science and Engineering, Saitama University , Saitama, Japan
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4
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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: 31] [Impact Index Per Article: 7.8] [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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5
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Jin H, Lao YM, Zhou J, Zhang HJ, Cai ZH. A rapid UHPLC-HILIC method for algal guanosine 5'-diphosphate 3'-diphosphate (ppGpp) and the potential separation mechanism. J Chromatogr B Analyt Technol Biomed Life Sci 2018; 1096:143-153. [PMID: 30170292 DOI: 10.1016/j.jchromb.2018.08.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 06/20/2018] [Accepted: 08/16/2018] [Indexed: 10/28/2022]
Abstract
A fast and facile hydrophilic interaction liquid chromatography (HILIC) method was developed and applied to quantify physiologically important ppGpp and its analogues in a tough sample, the astaxanthin-accumulating alga Hameatococcus pluvialis. The method is able to analyze simultaneously seven nucleotides, including ppGpp at the order of pmol g-1 cells within 12 min. Mechanism on the elution order was investigated. It was found that 1) phosphate salt competed for the amide groups on the HILIC column with the phosphate groups of the nucleotides; 2) intramolecular hydrogen bonds might contribute to the elution order by offsetting and reducing the number of free hydrogen acceptor/donor of the nucleotide molecules interacting with the amide groups. This is the first HILIC method for ppGpp, which is feasible and applicable to a wide range of samples, especially tough samples, e.g., algae and plants.
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Affiliation(s)
- Hui Jin
- Shenzhen Public Platform of Screening & Application of Marine Microbial Resources, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China; Shenzhen Key Laboratory for Coastal Ocean Dynamic and Environment, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China
| | - Yong Min Lao
- Shenzhen Public Platform of Screening & Application of Marine Microbial Resources, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China; Shenzhen Key Laboratory for Coastal Ocean Dynamic and Environment, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China
| | - Jin Zhou
- Shenzhen Public Platform of Screening & Application of Marine Microbial Resources, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China; Shenzhen Key Laboratory for Coastal Ocean Dynamic and Environment, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China
| | - Huai Jin Zhang
- School of Life Sciences, Tsinghua University, Beijing 100084, PR China
| | - Zhong Hua Cai
- Shenzhen Public Platform of Screening & Application of Marine Microbial Resources, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China; Shenzhen Key Laboratory for Coastal Ocean Dynamic and Environment, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China.
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6
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Boniecka J, Prusińska J, Dąbrowska GB, Goc A. Within and beyond the stringent response-RSH and (p)ppGpp in plants. PLANTA 2017; 246:817-842. [PMID: 28948393 PMCID: PMC5633626 DOI: 10.1007/s00425-017-2780-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 09/17/2017] [Indexed: 05/06/2023]
Abstract
Plant RSH proteins are able to synthetize and/or hydrolyze unusual nucleotides called (p)ppGpp or alarmones. These molecules regulate nuclear and chloroplast transcription, chloroplast translation and plant development and stress response. Homologs of bacterial RelA/SpoT proteins, designated RSH, and products of their activity, (p)ppGpp-guanosine tetra-and pentaphosphates, have been found in algae and higher plants. (p)ppGpp were first identified in bacteria as the effectors of the stringent response, a mechanism that orchestrates pleiotropic adaptations to nutritional deprivation and various stress conditions. (p)ppGpp accumulation in bacteria decreases transcription-with exception to genes that help to withstand or overcome current stressful situations, which are upregulated-and translation as well as DNA replication and eventually reduces metabolism and growth but promotes adaptive responses. In plants, RSH are nuclei-encoded and function in chloroplasts, where alarmones are produced and decrease transcription, translation, hormone, lipid and metabolites accumulation and affect photosynthetic efficiency and eventually plant growth and development. During senescence, alarmones coordinate nutrient remobilization and relocation from vegetative tissues into seeds. Despite the high conservancy of RSH protein domains among bacteria and plants as well as the bacterial origin of plant chloroplasts, in plants, unlike in bacteria, (p)ppGpp promote chloroplast DNA replication and division. Next, (p)ppGpp may also perform their functions in cytoplasm, where they would promote plant growth inhibition. Furthermore, (p)ppGpp accumulation also affects nuclear gene expression, i.a., decreases the level of Arabidopsis defense gene transcripts, and promotes plants susceptibility towards Turnip mosaic virus. In this review, we summarize recent findings that show the importance of RSH and (p)ppGpp in plant growth and development, and open an area of research aiming to understand the function of plant RSH in response to stress.
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Affiliation(s)
- Justyna Boniecka
- Department of Genetics, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100, Toruń, Poland
| | - Justyna Prusińska
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Grażyna B Dąbrowska
- Department of Genetics, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100, Toruń, Poland.
| | - Anna Goc
- Department of Genetics, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100, Toruń, Poland
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Ihara Y, Ohta H, Masuda S. A highly sensitive quantification method for the accumulation of alarmone ppGpp in Arabidopsis thaliana using UPLC-ESI-qMS/MS. JOURNAL OF PLANT RESEARCH 2015; 128:511-8. [PMID: 25752614 DOI: 10.1007/s10265-015-0711-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 01/04/2015] [Indexed: 05/09/2023]
Abstract
Recently, a bacterial second messenger, guanosine 5'-diphosphate 3'-diphosphate (ppGpp), has been detected in chloroplasts. However, because ppGpp concentration in plants is much lower than that in bacteria, detailed analysis of ppGpp in plants has not been performed. A highly sensitive quantification method is required for further characterization of ppGpp function in chloroplasts. Here, we report a new method that allows for the highly sensitive and selective high-throughput quantification of ppGpp by ultra-performance liquid chromatography (UPLC) coupled with a tandem quadrupole mass spectrometer (qMS/MS) equipped with an electrospray interface (ESI). This method requires only ~100 mg of plant tissue for ppGpp quantification. We used this method to measure ppGpp levels in Arabidopsis thaliana under different light conditions. A. thaliana accumulated ppGpp during dark periods. This method will be helpful to further characterize the stringent response in higher plants.
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Affiliation(s)
- Yuta Ihara
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan
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Sato M, Takahashi T, Ochi K, Matsuura H, Nabeta K, Takahashi K. Overexpression of RelA/SpoT homologs, PpRSH2a and PpRSH2b, induces the growth suppression of the moss Physcomitrella patens. Biosci Biotechnol Biochem 2014; 79:36-44. [PMID: 25228236 DOI: 10.1080/09168451.2014.952617] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Two genes encoding RelA/SpoT homologs, PpRSH2a and PpRSH2b, which are involved in the synthesis of bacterial alarmone guanosine 5'-diphosphate 3'-diphosphate (ppGpp) for the stringent response, were isolated from the moss, Physcomitrella patens. A complementary analysis of PpRSH2a and PpRSH2b in Escherichia coli showed that these genes had ppGpp biosynthetic activity. The recombinant PpRSH2a and PpRSH2b were also shown to synthesize ppGpp in vitro. Both proteins were localized to the chloroplasts of P. patens. Expression of the PpRSH genes was induced upon treatment with abscisic acid or abiotic stresses, such as dehydration and UV irradiation. Overexpression of PpRSH2a and PpRSH2b caused suppression of the growth in response to 1% (w/v) of glucose. The present study suggests the existence of a mechanism to regulate the growth of P. patens, which is governed by plant RSH in chloroplasts.
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Affiliation(s)
- Michio Sato
- a Research Faculty of Agriculture, Division of Applied Bioscience , Hokkaido University , Sapporo , Japan
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9
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Nomura Y, Izumi A, Fukunaga Y, Kusumi K, Iba K, Watanabe S, Nakahira Y, Weber APM, Nozawa A, Tozawa Y. Diversity in guanosine 3',5'-bisdiphosphate (ppGpp) sensitivity among guanylate kinases of bacteria and plants. J Biol Chem 2014; 289:15631-41. [PMID: 24722991 PMCID: PMC4140918 DOI: 10.1074/jbc.m113.534768] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 03/20/2014] [Indexed: 11/06/2022] Open
Abstract
The guanosine 3',5'-bisdiphosphate (ppGpp) signaling system is shared by bacteria and plant chloroplasts, but its role in plants has remained unclear. Here we show that guanylate kinase (GK), a key enzyme in guanine nucleotide biosynthesis that catalyzes the conversion of GMP to GDP, is a target of regulation by ppGpp in chloroplasts of rice, pea, and Arabidopsis. Plants have two distinct types of GK that are localized to organelles (GKpm) or to the cytosol (GKc), with both enzymes being essential for growth and development. We found that the activity of rice GKpm in vitro was inhibited by ppGpp with a Ki of 2.8 μM relative to the substrate GMP, whereas the Km of this enzyme for GMP was 73 μM. The IC50 of ppGpp for GKpm was ∼10 μM. In contrast, the activity of rice GKc was insensitive to ppGpp, as was that of GK from bakers' yeast, which is also a cytosolic enzyme. These observations suggest that ppGpp plays a pivotal role in the regulation of GTP biosynthesis in chloroplasts through specific inhibition of GKpm activity, with the regulation of GTP biosynthesis in chloroplasts thus being independent of that in the cytosol. We also found that GKs of Escherichia coli and Synechococcus elongatus PCC 7942 are insensitive to ppGpp, in contrast to the ppGpp sensitivity of the Bacillus subtilis enzyme. Our biochemical characterization of GK enzymes has thus revealed a novel target of ppGpp in chloroplasts and has uncovered diversity among bacterial GKs with regard to regulation by ppGpp.
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Affiliation(s)
- Yuhta Nomura
- From the Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577, Japan, the Proteo-Science Center and the Venture Business Laboratory, Ehime University, Matsuyama 790-8577, Japan
| | - Atsushi Izumi
- the Proteo-Science Center and the Venture Business Laboratory, Ehime University, Matsuyama 790-8577, Japan
| | - Yoshinori Fukunaga
- From the Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577, Japan, the Proteo-Science Center and the Venture Business Laboratory, Ehime University, Matsuyama 790-8577, Japan
| | - Kensuke Kusumi
- the Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan
| | - Koh Iba
- the Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan
| | - Seiya Watanabe
- the Faculty of Agriculture, Ehime University, Matsuyama 790-8566, Japan
| | - Yoichi Nakahira
- the Proteo-Science Center and the Venture Business Laboratory, Ehime University, Matsuyama 790-8577, Japan
| | - Andreas P M Weber
- the Institute for Plant Biochemistry, Cluster of Excellence on Plant Sciences, Heinrich-Heine University, Düsseldorf D-40225, Germany
| | - Akira Nozawa
- the Proteo-Science Center and the Venture Business Laboratory, Ehime University, Matsuyama 790-8577, Japan
| | - Yuzuru Tozawa
- the Proteo-Science Center and the Venture Business Laboratory, Ehime University, Matsuyama 790-8577, Japan,
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Nomura Y, Nozawa A, Tozawa Y. Biochemical analyses of ppGpp effect on adenylosuccinate synthetases, key enzymes in purine biosynthesis in rice. Biosci Biotechnol Biochem 2014; 78:1022-5. [PMID: 25036129 DOI: 10.1080/09168451.2014.910103] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The ppGpp-signaling system functions in plant chloroplasts. In bacteria, a negative effect of ppGpp on adenylosuccinate synthetase (AdSS) has been suggested. Our biochemical analysis also revealed rice AdSS homologs are apparently sensitive to ppGpp. However, further investigation clarified that this phenomenon is cancelled by the high substrate affinity to the enzymes, leading to a limited effect of ppGpp on adenylosuccinate synthesis.
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Affiliation(s)
- Yuhta Nomura
- a Graduate School of Science and Engineering , Ehime University , Matsuyama , Japan
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Kusumi K, Iba K. Establishment of the chloroplast genetic system in rice during early leaf development and at low temperatures. FRONTIERS IN PLANT SCIENCE 2014; 5:386. [PMID: 25157260 PMCID: PMC4127815 DOI: 10.3389/fpls.2014.00386] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Accepted: 07/20/2014] [Indexed: 05/05/2023]
Abstract
Chloroplasts are the central nodes of the metabolic network in leaf cells of higher plants, and the conversion of proplastids into chloroplasts is tightly coupled to leaf development. During early leaf development, the structure and function of the chloroplasts differ greatly from those in a mature leaf, suggesting the existence of a stage-specific mechanism regulating chloroplast development during this period. Here, we discuss the identification of the genes affected in low temperature-conditional mutants of rice (Oryza sativa). These genes encode factors involved in chloroplast rRNA regulation (NUS1), and nucleotide metabolism in mitochondria, chloroplasts, and cytosol (V2 , V3, ST1). These genes are all preferentially expressed in the early leaf developmental stage P4, and depleting them causes altered chloroplast transcription and translation, and ultimately leaf chlorosis. Therefore, it is suggested that regulation of cellular nucleotide pools and nucleotide metabolism is indispensable for chloroplast development under low temperatures at this stage. This review summarizes the current understanding of these factors and discusses their roles in chloroplast biogenesis.
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Affiliation(s)
- Kensuke Kusumi
- *Correspondence: Kensuke Kusumi, Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan e-mail:
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12
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Sugisaki K, Hanawa T, Yonezawa H, Osaki T, Fukutomi T, Kawakami H, Yamamoto T, Kamiya S. Role of (p)ppGpp in biofilm formation and expression of filamentous structures in Bordetella pertussis. MICROBIOLOGY-SGM 2013; 159:1379-1389. [PMID: 23676431 DOI: 10.1099/mic.0.066597-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Bordetella pertussis, the causative agent of whooping cough, is highly adapted to cause human infection. The production of virulence factors, such as adhesins and toxins, is just part of an array of mechanisms by which B. pertussis causes infection. The stringent response is a global bacterial response to nutritional limitation that is mediated by the accumulation of cellular ppGpp and pppGpp [termed together as (p)ppGpp]. Here, we demonstrate that production of (p)ppGpp was controlled by RelA and SpoT proteins in B. pertussis, and that mutation-induced loss of both proteins together caused deficiencies in (p)ppGpp production. The (p)ppGpp-deficient mutants also exhibited defects in growth regulation, decreases in viability under nutritionally limited conditions, increases in susceptibility to oxidative stress and defects in biofilm formation. Analysis of the secreted proteins and the respective transcripts showed that lack of (p)ppGpp led to decreased expression of fim3 and bsp22, which encode a fimbrial subunit and the self-polymerizing type III secretion system tip protein, respectively. Moreover, electron microscopic analysis also indicated that (p)ppGpp regulated the formation of filamentous structures. Most virulence genes - including fim3 and bsp22 - were expressed in the Bvg(+) phase during which the BvgAS two-component system was activated. Although fim3 and bsp22 were downregulated in a (p)ppGpp-deficient mutant, normal expression of fhaB, cyaA and ptxA persisted. Lack of coherence between virulence gene expression and (p)ppGpp production indicated that (p)ppGpp did not modulate the Bvg phase. Taken together, our data indicate that (p)ppGpp may govern an as-yet-unrecognized system that influences B. pertussis pathogenicity.
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Affiliation(s)
- Kentaro Sugisaki
- Department of Infectious Diseases, Kyorin University School of Medicine, 6-20-2, Shinkawa, Mitaka, Tokyo 181-8611, Japan
| | - Tomoko Hanawa
- Department of Infectious Diseases, Kyorin University School of Medicine, 6-20-2, Shinkawa, Mitaka, Tokyo 181-8611, Japan
| | - Hideo Yonezawa
- Department of Infectious Diseases, Kyorin University School of Medicine, 6-20-2, Shinkawa, Mitaka, Tokyo 181-8611, Japan
| | - Takako Osaki
- Department of Infectious Diseases, Kyorin University School of Medicine, 6-20-2, Shinkawa, Mitaka, Tokyo 181-8611, Japan
| | - Toshiyuki Fukutomi
- Department of Pharmacology, Kyorin University School of Medicine, 6-20-2, Shinkawa, Mitaka, Tokyo 181-8611, Japan
| | - Hayato Kawakami
- Department of Anatomy, Kyorin University School of Medicine, 6-20-2, Shinkawa, Mitaka, Tokyo 181-8611, Japan
| | - Tomoko Yamamoto
- Department of Microbiology and Molecular Genetics, Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba-shi, Chiba 260-8675, Japan
| | - Shigeru Kamiya
- Department of Infectious Diseases, Kyorin University School of Medicine, 6-20-2, Shinkawa, Mitaka, Tokyo 181-8611, Japan
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Enzymatic and molecular characterization of Arabidopsis ppGpp pyrophosphohydrolase, AtNUDX26. Biosci Biotechnol Biochem 2012; 76:2236-41. [PMID: 23221701 DOI: 10.1271/bbb.120523] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Not only in bacteria but also in plant cells, guanosine-3',5'-tetraphosphate (ppGpp) is an important signaling molecule, that affects various cellular processes. In this study, we identified nucleoside diphosphates linked to some moiety X (Nudix) hydrolases, AtNUDX11, 15, 25, and 26, having ppGpp pyrophosphohydrolase activity from Arabidopsis plants. Among these, AtNUDX26 localized in chloroplasts had the highest Vmax and kcat values, leading to high catalytic efficiency, kcat/Km. The activity of AtNUDX26 required Mg2+ or Mn2+ ions as cofactor and was optimal at pH 9.0 and 50 °C. The expression of AtNUDX26 and of ppGpp metabolism-associated genes was regulated by various types of stress, suggesting that AtNUDX26 regulates cellular ppGpp levels in response to stress and impacts gene expression in chloroplasts. This is the first report on the molecular properties of ppGpp pyrophosphohydrolases in plants.
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Martucci NM, Lamberti A, Vitagliano L, Cantiello P, Ruggiero I, Arcari P, Masullo M. The magic spot ppGpp influences in vitro the molecular and functional properties of the elongation factor 1α from the archaeon Sulfolobus solfataricus. Extremophiles 2012; 16:743-9. [PMID: 22772751 DOI: 10.1007/s00792-012-0470-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 06/21/2012] [Indexed: 12/01/2022]
Abstract
Guanosine tetra-phosphate (ppGpp), also known as "magic spot I", is a key molecule in the stringent control of most eubacteria and some eukarya. Here, we show that ppGpp affects the functional and molecular properties of the archaeal elongation factor 1α from Sulfolobus solfataricus (SsEF-1α). Indeed, ppGpp inhibited archaeal protein synthesis in vitro, even though the concentration required to get inhibition was higher than that required for the eubacterial and eukaryal systems. Regarding the partial reactions catalysed by SsEF-1α the effect produced by ppGpp on the affinity for aa-tRNA was lower than that measured in the presence of GTP but higher than that for GDP. Magic spot I was also able to bind SsEF-1α with an intermediate affinity in comparison to that displayed by GDP and GTP. Furthermore, ppGpp inhibited the intrinsic GTPase of SsEF-1α with a competitive behaviour. Finally, the binding of ppGpp to SsEF-1α rendered the elongation factor more resistant to heat treatment and the analysis of the molecular model of the complex between SsEF-1α and ppGpp suggests that this stabilisation arises from the charge optimisation on the surface of the protein.
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Affiliation(s)
- Nicola M Martucci
- Dipartimento di Studi delle Istituzioni e dei Sistemi Territoriali, Università degli Studi di Napoli Parthenope, Via Medina 40, 80133 Naples, Italy
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