1
|
Pätsi HT, Kilpeläinen TP, Jumppanen M, Uhari-Väänänen J, Wielendaele PV, De Lorenzo F, Cui H, Auno S, Saharinen J, Seppälä E, Sipari N, Savinainen J, De Meester I, Lambeir AM, Lahtela-Kakkonen M, Myöhänen TT, Wallén EAA. 5-Aminothiazoles Reveal a New Ligand-Binding Site on Prolyl Oligopeptidase Which is Important for Modulation of Its Protein-Protein Interaction-Derived Functions. J Med Chem 2024; 67:5421-5436. [PMID: 38546708 DOI: 10.1021/acs.jmedchem.3c01993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
A series of novel 5-aminothiazole-based ligands for prolyl oligopeptidase (PREP) comprise selective, potent modulators of the protein-protein interaction (PPI)-mediated functions of PREP, although they are only weak inhibitors of the proteolytic activity of PREP. The disconnected structure-activity relationships are significantly more pronounced for the 5-aminothiazole-based ligands than for the earlier published 5-aminooxazole-based ligands. Furthermore, the stability of the 5-aminothiazole scaffold allowed exploration of wider substitution patterns than that was possible with the 5-aminooxazole scaffold. The intriguing structure-activity relationships for the modulation of the proteolytic activity and PPI-derived functions of PREP were elaborated by presenting a new binding site for PPI modulating PREP ligands, which was initially discovered using molecular modeling and later confirmed through point mutation studies. Our results suggest that this new binding site on PREP is clearly more important than the active site of PREP for the modulation of its PPI-mediated functions.
Collapse
Affiliation(s)
- Henri T Pätsi
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Tommi P Kilpeläinen
- Drug Research Program, Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Mikael Jumppanen
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Johanna Uhari-Väänänen
- Drug Research Program, Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Pieter Van Wielendaele
- Laboratory of Medical Biochemistry, Department of Pharmaceutical Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, 2610 Wilrijk, Belgium
| | - Francesca De Lorenzo
- Drug Research Program, Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Hengjing Cui
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Yliopistonranta 1C, 70211 Kuopio, Finland
| | - Samuli Auno
- Drug Research Program, Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Janne Saharinen
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Erin Seppälä
- School of Medicine/Biomedicine, Faculty of Health Sciences, University of Eastern Finland, Yliopistonranta 8, Kuopio 70211, Finland
| | - Nina Sipari
- Viikki Metabolomics Unit, Faculty of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 5 E, 00014 Helsinki, Finland
| | - Juha Savinainen
- School of Medicine/Biomedicine, Faculty of Health Sciences, University of Eastern Finland, Yliopistonranta 8, Kuopio 70211, Finland
| | - Ingrid De Meester
- Laboratory of Medical Biochemistry, Department of Pharmaceutical Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, 2610 Wilrijk, Belgium
| | - Anne-Marie Lambeir
- Laboratory of Medical Biochemistry, Department of Pharmaceutical Sciences, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, 2610 Wilrijk, Belgium
| | - Maija Lahtela-Kakkonen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Yliopistonranta 1C, 70211 Kuopio, Finland
| | - Timo T Myöhänen
- Drug Research Program, Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Yliopistonranta 1C, 70211 Kuopio, Finland
- Division of Pharmacology, Faculty of Medicine, University of Helsinki, P.O.Box 63, 00014 Helsinki, Finland
| | - Erik A A Wallén
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| |
Collapse
|
2
|
Waszczak C, Yarmolinsky D, Leal Gavarrón M, Vahisalu T, Sierla M, Zamora O, Carter R, Puukko T, Sipari N, Lamminmäki A, Durner J, Ernst D, Winkler JB, Paulin L, Auvinen P, Fleming AJ, Andersson MX, Kollist H, Kangasjärvi J. Synthesis and import of GDP-l-fucose into the Golgi affect plant-water relations. New Phytol 2024; 241:747-763. [PMID: 37964509 DOI: 10.1111/nph.19378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 10/13/2023] [Indexed: 11/16/2023]
Abstract
Land plants evolved multiple adaptations to restrict transpiration. However, the underlying molecular mechanisms are not sufficiently understood. We used an ozone-sensitivity forward genetics approach to identify Arabidopsis thaliana mutants impaired in gas exchange regulation. High water loss from detached leaves and impaired decrease of leaf conductance in response to multiple stomata-closing stimuli were identified in a mutant of MURUS1 (MUR1), an enzyme required for GDP-l-fucose biosynthesis. High water loss observed in mur1 was independent from stomatal movements and instead could be linked to metabolic defects. Plants defective in import of GDP-l-Fuc into the Golgi apparatus phenocopied the high water loss of mur1 mutants, linking this phenotype to Golgi-localized fucosylation events. However, impaired fucosylation of xyloglucan, N-linked glycans, and arabinogalactan proteins did not explain the aberrant water loss of mur1 mutants. Partial reversion of mur1 water loss phenotype by borate supplementation and high water loss observed in boron uptake mutants link mur1 gas exchange phenotypes to pleiotropic consequences of l-fucose and boron deficiency, which in turn affect mechanical and morphological properties of stomatal complexes and whole-plant physiology. Our work emphasizes the impact of fucose metabolism and boron uptake on plant-water relations.
Collapse
Affiliation(s)
- Cezary Waszczak
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
| | | | - Marina Leal Gavarrón
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
| | - Triin Vahisalu
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
| | - Maija Sierla
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
| | - Olena Zamora
- Institute of Technology, University of Tartu, 50411, Tartu, Estonia
| | - Ross Carter
- Sainsbury Laboratory, University of Cambridge, CB2 1LR, Cambridge, UK
| | - Tuomas Puukko
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
| | - Nina Sipari
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
- Viikki Metabolomics Unit, Faculty of Biological and Environmental Sciences, University of Helsinki, FI-00014, Helsinki, Finland
| | - Airi Lamminmäki
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
| | - Jörg Durner
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Dieter Ernst
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - J Barbro Winkler
- Research Unit Environmental Simulation, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Lars Paulin
- Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland
| | - Petri Auvinen
- Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland
| | - Andrew J Fleming
- School of Biosciences, University of Sheffield, S10 2TN, Sheffield, UK
| | - Mats X Andersson
- Department of Biological and Environmental Sciences, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Hannes Kollist
- Institute of Technology, University of Tartu, 50411, Tartu, Estonia
| | - Jaakko Kangasjärvi
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
| |
Collapse
|
3
|
Vainio J, Mattila S, Abdou SM, Sipari N, Teeri TH. Petunia dihydroflavonol 4-reductase is only a few amino acids away from producing orange pelargonidin-based anthocyanins. Front Plant Sci 2023; 14:1227219. [PMID: 37645465 PMCID: PMC10461392 DOI: 10.3389/fpls.2023.1227219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 07/21/2023] [Indexed: 08/31/2023]
Abstract
Anthocyanins are responsible for the color spectrum of both ornamental and natural flowers. However, not all plant species produce all colors. For example, roses are not blue because they do not naturally possess a hydroxylase that opens the pathway for delphinidin and its derivatives. It is more intriguing why some plants do not carry orange or scarlet red flowers with anthocyanins based on pelargonidin, because the precursor for these anthocyanins should be available if anthocyanins are made at all. The key to this is the substrate specificity of dihydroflavonol 4-reductase (DFR), an enzyme located at the branch point between flavonols and anthocyanins. The most common example is petunia, which does not bear orange flowers unless the enzyme is complemented by biotechnology. We changed a few amino acids in the active site of the enzyme and showed that the mutated petunia DFR started to favor dihydrokaempferol, the precursor to orange pelargonidin, in vitro. When transferred to petunia, it produced an orange hue and dramatically more pelargonidin-based anthocyanins in the flowers.
Collapse
Affiliation(s)
- Jere Vainio
- Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
| | - Saku Mattila
- Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
| | - Sara M. Abdou
- Horticulture and Product Physiology Group, Wageningen University, Wageningen, Netherlands
| | - Nina Sipari
- Viikki Metabolomics Unit, University of Helsinki, Helsinki, Finland
| | - Teemu H. Teeri
- Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
- Viikki Metabolomics Unit, University of Helsinki, Helsinki, Finland
| |
Collapse
|
4
|
Sunden M, Upadhyay D, Banerjee R, Sipari N, Fellman V, Kallijärvi J, Purhonen J. Enzymatic assay for UDP-GlcNAc and its application in the parallel assessment of substrate availability and protein O-GlcNAcylation. Cell Rep Methods 2023; 3:100518. [PMID: 37533645 PMCID: PMC10391344 DOI: 10.1016/j.crmeth.2023.100518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 05/11/2023] [Accepted: 06/05/2023] [Indexed: 08/04/2023]
Abstract
O-linked N-acetylglucosaminylation (O-GlcNAcylation) is a ubiquitous and dynamic non-canonical glycosylation of intracellular proteins. Several branches of metabolism converge at the hexosamine biosynthetic pathway (HBP) to produce the substrate for protein O-GlcNAcylation, the uridine diphosphate N-acetylglucosamine (UDP-GlcNAc). Availability of UDP-GlcNAc is considered a key regulator of O-GlcNAcylation. Yet UDP-GlcNAc concentrations are rarely reported in studies exploring the HBP and O-GlcNAcylation, most likely because the methods to measure it are restricted to specialized chromatographic procedures. Here, we introduce an enzymatic method to quantify cellular and tissue UDP-GlcNAc. The method is based on O-GlcNAcylation of a substrate peptide by O-linked N-acetylglucosamine transferase (OGT) and subsequent immunodetection of the modification. The assay can be performed in dot-blot or microplate format. We apply it to quantify UDP-GlcNAc concentrations in several mouse tissues and cell lines. Furthermore, we show how changes in UDP-GlcNAc levels correlate with O-GlcNAcylation and the expression of OGT and O-GlcNAcase (OGA).
Collapse
Affiliation(s)
- Marc Sunden
- Folkhälsan Research Center, Helsinki, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Divya Upadhyay
- Folkhälsan Research Center, Helsinki, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Rishi Banerjee
- Folkhälsan Research Center, Helsinki, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Nina Sipari
- Viikki Metabolomics Unit, University of Helsinki, Helsinki, Finland
| | - Vineta Fellman
- Folkhälsan Research Center, Helsinki, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Children’s Hospital, Helsinki University Hospital, Helsinki, Finland
- Pediatrics, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Jukka Kallijärvi
- Folkhälsan Research Center, Helsinki, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Janne Purhonen
- Folkhälsan Research Center, Helsinki, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| |
Collapse
|
5
|
Kilpeläinen TP, Pätsi HT, Svarcbahs R, Julku UH, Eteläinen TS, Cui H, Auno S, Sipari N, Norrbacka S, Leino TO, Jäntti M, Myöhänen TT, Wallén EAA. Nonpeptidic Oxazole-Based Prolyl Oligopeptidase Ligands with Disease-Modifying Effects on α-Synuclein Mouse Models of Parkinson's Disease. J Med Chem 2023. [PMID: 37248563 DOI: 10.1021/acs.jmedchem.3c00235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Prolyl oligopeptidase (PREP) is a widely distributed serine protease in the human body cleaving proline-containing peptides; however, recent studies suggest that its effects on pathogenic processes underlying neurodegeneration are derived from direct protein-protein interactions (PPIs) and not from its regulation of certain neuropeptide levels. We discovered novel nonpeptidic oxazole-based PREP inhibitors, which deviate from the known structure-activity relationship for PREP inhibitors. These new compounds are effective modulators of the PPIs of PREP, reducing α-synuclein (αSyn) dimerization and enhancing protein phosphatase 2A activity in a concentration-response manner, as well as reducing reactive oxygen species production. From the best performing oxazoles, HUP-55 was selected for in vivo studies. Its brain penetration was evaluated, and it was tested in αSyn virus vector-based and αSyn transgenic mouse models of Parkinson's disease, where it restored motor impairment and reduced levels of oligomerized αSyn in the striatum and substantia nigra.
Collapse
Affiliation(s)
| | | | | | | | | | - Hengjing Cui
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Yliopistonranta 1C, 70211 Kuopio, Finland
| | | | - Nina Sipari
- Viikki Metabolomics Unit, Department of Biosciences, University of Helsinki, Viikinkaari 5 E, 00014 Helsinki, Finland
| | | | | | | | - Timo T Myöhänen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Yliopistonranta 1C, 70211 Kuopio, Finland
| | | |
Collapse
|
6
|
Purhonen J, Banerjee R, Wanne V, Sipari N, Mörgelin M, Fellman V, Kallijärvi J. Mitochondrial complex III deficiency drives c-MYC overexpression and illicit cell cycle entry leading to senescence and segmental progeria. Nat Commun 2023; 14:2356. [PMID: 37095097 PMCID: PMC10126100 DOI: 10.1038/s41467-023-38027-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 04/12/2023] [Indexed: 04/26/2023] Open
Abstract
Accumulating evidence suggests mitochondria as key modulators of normal and premature aging, yet whether primary oxidative phosphorylation (OXPHOS) deficiency can cause progeroid disease remains unclear. Here, we show that mice with severe isolated respiratory complex III (CIII) deficiency display nuclear DNA damage, cell cycle arrest, aberrant mitoses, and cellular senescence in the affected organs such as liver and kidney, and a systemic phenotype resembling juvenile-onset progeroid syndromes. Mechanistically, CIII deficiency triggers presymptomatic cancer-like c-MYC upregulation followed by excessive anabolic metabolism and illicit cell proliferation against lack of energy and biosynthetic precursors. Transgenic alternative oxidase dampens mitochondrial integrated stress response and the c-MYC induction, suppresses the illicit proliferation, and prevents juvenile lethality despite that canonical OXPHOS-linked functions remain uncorrected. Inhibition of c-MYC with the dominant-negative Omomyc protein relieves the DNA damage in CIII-deficient hepatocytes in vivo. Our results connect primary OXPHOS deficiency to genomic instability and progeroid pathogenesis and suggest that targeting c-MYC and aberrant cell proliferation may be therapeutic in mitochondrial diseases.
Collapse
Affiliation(s)
- Janne Purhonen
- Folkhälsan Research Center, Haartmaninkatu 8, 00290, Helsinki, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, P.O.Box 63, 00014, Helsinki, Finland
| | - Rishi Banerjee
- Folkhälsan Research Center, Haartmaninkatu 8, 00290, Helsinki, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, P.O.Box 63, 00014, Helsinki, Finland
| | - Vilma Wanne
- Folkhälsan Research Center, Haartmaninkatu 8, 00290, Helsinki, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, P.O.Box 63, 00014, Helsinki, Finland
| | - Nina Sipari
- Viikki Metabolomics Unit, University of Helsinki, P.O.Box 65, Helsinki, Finland
| | - Matthias Mörgelin
- Division of Infection Medicine, Department of Clinical Sciences, Lund University, P.O.Box 117, 221 00, Lund, Sweden
- Colzyx AB, Scheelevägen 2, 22381, Lund, Sweden
| | - Vineta Fellman
- Folkhälsan Research Center, Haartmaninkatu 8, 00290, Helsinki, Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, P.O.Box 63, 00014, Helsinki, Finland
- Department of Clinical Sciences, Lund, Pediatrics, Lund University, P.O.Box 117, 221 00, Lund, Sweden
- Children's Hospital, Clinicum, University of Helsinki, P.O. Box 22, 00014, Helsinki, Finland
| | - Jukka Kallijärvi
- Folkhälsan Research Center, Haartmaninkatu 8, 00290, Helsinki, Finland.
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, P.O.Box 63, 00014, Helsinki, Finland.
| |
Collapse
|
7
|
Pollari M, Sipari N, Poque S, Himanen K, Mäkinen K. Effects of Poty-Potexvirus Synergism on Growth, Photosynthesis and Metabolite Status of Nicotiana benthamiana. Viruses 2022; 15:121. [PMID: 36680161 PMCID: PMC9867248 DOI: 10.3390/v15010121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 01/03/2023] Open
Abstract
Mixed virus infections threaten crop production because interactions between the host and the pathogen mix may lead to viral synergism. While individual infections by potato virus A (PVA), a potyvirus, and potato virus X (PVX), a potexvirus, can be mild, co-infection leads to synergistic enhancement of PVX and severe symptoms. We combined image-based phenotyping with metabolite analysis of single and mixed PVA and PVX infections and compared their effects on growth, photosynthesis, and metabolites in Nicotiana benthamiana. Viral synergism was evident in symptom severity and impaired growth in the plants. Indicative of stress, the co-infection increased leaf temperature and decreased photosynthetic parameters. In contrast, singly infected plants sustained photosynthetic activity. The host's metabolic response differed significantly between single and mixed infections. Over 200 metabolites were differentially regulated in the mixed infection: especially defense-related metabolites and aromatic and branched-chain amino acids increased compared to the control. Changes in the levels of methionine cycle intermediates and a low S-adenosylmethionine/S-adenosylhomocysteine ratio suggested a decline in the methylation potential in co-infected plants. The decreased ratio between reduced glutathione, an important scavenger of reactive oxygen species, and its oxidized form, indicated that severe oxidative stress developed during co-infection. Based on the results, infection-associated oxidative stress is successfully controlled in the single infections but not in the synergistic infection, where activated defense pathways are not sufficient to counter the impact of the infections on plant growth.
Collapse
Affiliation(s)
- Maija Pollari
- Department of Microbiology, Viikki Plant Science Centre, University of Helsinki, 00014 Helsinki, Finland
| | - Nina Sipari
- Viikki Metabolomics Unit, Organismal and Evolutionary Biology Research Programme, Viikki Plant Science Centre, University of Helsinki, 00014 Helsinki, Finland
| | - Sylvain Poque
- Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, 00014 Helsinki, Finland
| | - Kristiina Himanen
- National Plant Phenotyping Infrastructure, HiLIFE, Biocenter Finland, Viikki Plant Science Centre, University of Helsinki, 00014 Helsinki, Finland
| | - Kristiina Mäkinen
- Department of Microbiology, Viikki Plant Science Centre, University of Helsinki, 00014 Helsinki, Finland
| |
Collapse
|
8
|
Sipari N, Lihavainen J, Keinänen M. Metabolite Profiling of Paraquat Tolerant Arabidopsis thaliana Radical-induced Cell Death1 ( rcd1)-A Mediator of Antioxidant Defence Mechanisms. Antioxidants (Basel) 2022; 11:antiox11102034. [PMID: 36290757 PMCID: PMC9598866 DOI: 10.3390/antiox11102034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/06/2022] [Accepted: 10/13/2022] [Indexed: 11/16/2022] Open
Abstract
RADICAL-INDUCED CELL DEATH1 (RCD1) is an Arabidopsis thaliana nuclear protein that is disrupted during oxidative stress. RCD1 is considered an important integrative node in development and stress responses, and the rcd1 plants have several phenotypes and altered resistance to a variety of abiotic and biotic stresses. One of the phenotypes of rcd1 is resistance to the herbicide paraquat, but the mechanisms behind it are unknown. Paraquat causes a rapid burst of reactive oxygen species (ROS) initially in the chloroplast. We performed multi-platform metabolomic analyses in wild type Col-0 and paraquat resistant rcd1 plants to identify pathways conveying resistance and the function of RCD1 in this respect. Wild type and rcd1 plants were clearly distinguished by their abundance of antioxidants and specialized metabolites and their responses to paraquat. The lack of response in rcd1 suggested constitutively active defense against ROS via elevated flavonoid, glutathione, β-carotene, and tocopherol levels, whereas its ascorbic acid levels were compromised under non-stressed control conditions when compared to Col-0. We propose that RCD1 acts as a hub that maintains basal antioxidant system, and its inactivation induces defense responses by enhancing the biosynthesis and redox cycling of low molecular weight antioxidants and specialized metabolites with profound antioxidant activities alleviating oxidative stress.
Collapse
Affiliation(s)
- Nina Sipari
- Viikki Metabolomics Unit, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65, FI-00014 Helsinki, Finland
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
- Correspondence: (N.S.); (M.K.)
| | - Jenna Lihavainen
- Umeå Plant Science Center, Department of Plant Physiology, Umeå Universitet, 90 187 Umeå, Sweden
| | - Markku Keinänen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
- Institute of Photonics, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
- Correspondence: (N.S.); (M.K.)
| |
Collapse
|
9
|
Hadizadeh I, Peivastegan B, Wang J, Sipari N, Nielsen KL, Pirhonen M. Gene expression and phytohormone levels in the asymptomatic and symptomatic phases of infection in potato tubers inoculated with Dickeya solani. PLoS One 2022; 17:e0273481. [PMID: 36037153 PMCID: PMC9423618 DOI: 10.1371/journal.pone.0273481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 08/10/2022] [Indexed: 11/28/2022] Open
Abstract
Dickeya solani is a soft rot bacterium with high virulence. In potato, D. solani, like the other potato-infecting soft rot bacteria, causes rotting and wilting of the stems and rotting of tubers in the field and in storage. Latent, asymptomatic infections of potato tubers are common in harvested tubers, and if the storage conditions are not optimal, the latent infection turns into active rotting. We characterized potato gene expression in artificially inoculated tubers in nonsymptomatic, early infections 1 and 24 hours post-inoculation (hpi) and compared the results to the response in symptomatic tuber tissue 1 week (168 hpi) later with RNA-Seq. In the beginning of the infection, potato tubers expressed genes involved in the detection of the bacterium through pathogen-associated molecular patterns (PAMPs), which induced genes involved in PAMPs-triggered immunity, resistance, production of pathogenesis-related proteins, ROS, secondary metabolites and salicylic acid (SA) and jasmonic acid (JA) biosynthesis and signaling genes. In the symptomatic tuber tissue one week later, the PAMPs-triggered gene expression was downregulated, whereas primary metabolism was affected, most likely leading to free sugars fueling plant defense but possibly also aiding the growth of the pathogen. In the symptomatic tubers, pectic enzymes and cell wall-based defenses were activated. Measurement of hormone production revealed increased SA concentration and almost no JA in the asymptomatic tubers at the beginning of the infection and high level of JA and reduced SA in the symptomatic tubers one week later. These findings suggest that potato tubers rely on different defense strategies in the different phases of D. solani infection even when the infection takes place in fully susceptible plants incubated in conditions leading to rotting. These results support the idea that D. solani is a biotroph rather than a true necrotroph.
Collapse
Affiliation(s)
- Iman Hadizadeh
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland
| | - Bahram Peivastegan
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland
| | - Jinhui Wang
- College of Plant Protection, Hebei Agricultural University, Hebei, China
| | - Nina Sipari
- Viikki Metabolomics Unit, Faculty of Biological and Environmental sciences, University of Helsinki, Helsinki, Finland
| | | | - Minna Pirhonen
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland
- * E-mail:
| |
Collapse
|
10
|
Hieta JP, Sipari N, Räikkönen H, Keinänen M, Kostiainen R. Mass Spectrometry Imaging of Arabidopsis thaliana Leaves at the Single-Cell Level by Infrared Laser Ablation Atmospheric Pressure Photoionization (LAAPPI). J Am Soc Mass Spectrom 2021; 32:2895-2903. [PMID: 34738804 PMCID: PMC8640987 DOI: 10.1021/jasms.1c00295] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In this study, we show that infrared laser ablation atmospheric pressure photoionization mass spectrometry (LAAPPI-MS) imaging with 70 μm lateral resolution allows for the analysis of Arabidopsis thaliana (A. thaliana) leaf substructures ranging from single-cell trichomes and the interveinal leaf lamina to primary, secondary, and tertiary veins. The method also showed its potential for depth profiling analysis for the first time by mapping analytes at the different depths of the leaf and spatially resolving the topmost trichomes and cuticular wax layer from the underlying tissues. Negative ion LAAPPI-MS detected many different flavonol glycosides, fatty acids, fatty acid esters, galactolipids, and glycosphingolipids, whose distributions varied significantly between the different substructures of A. thaliana leaves. The results show that LAAPPI-MS provides a highly promising new tool to study the role of metabolites in plants.
Collapse
Affiliation(s)
- Juha-Pekka Hieta
- Drug
Research Program and Division of Pharmaceutical Chemistry and Technology,
Faculty of Pharmacy, University of Helsinki, P.O. Box 56, Helsinki 00014, Finland
| | - Nina Sipari
- Viikki
Metabolomics Unit, Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 56, Helsinki 00014, Finland
| | - Heikki Räikkönen
- Drug
Research Program and Division of Pharmaceutical Chemistry and Technology,
Faculty of Pharmacy, University of Helsinki, P.O. Box 56, Helsinki 00014, Finland
| | - Markku Keinänen
- Department
of Environmental and Biological Sciences, Institute of Photonics,
Faculty of Science and Forestry, University
of Eastern Finland, P.O. Box 111, Joensuu 80101, Finland
| | - Risto Kostiainen
- Drug
Research Program and Division of Pharmaceutical Chemistry and Technology,
Faculty of Pharmacy, University of Helsinki, P.O. Box 56, Helsinki 00014, Finland
| |
Collapse
|
11
|
Samkumar A, Jones D, Karppinen K, Dare AP, Sipari N, Espley RV, Martinussen I, Jaakola L. Red and blue light treatments of ripening bilberry fruits reveal differences in signalling through abscisic acid-regulated anthocyanin biosynthesis. Plant Cell Environ 2021; 44:3227-3245. [PMID: 34337774 DOI: 10.1111/pce.14158] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/19/2021] [Accepted: 07/19/2021] [Indexed: 05/28/2023]
Abstract
The biosynthesis of anthocyanins has been shown to be influenced by light quality. However, the molecular mechanisms underlying the light-mediated regulation of fruit anthocyanin biosynthesis are not well understood. In this study, we analysed the effects of supplemental red and blue light on the anthocyanin biosynthesis in non-climacteric bilberry (Vaccinium myrtillus L.). After 6 days of continuous irradiation during ripening, both red and blue light elevated concentration of anthocyanins, up to 12- and 4-folds, respectively, compared to the control. Transcriptomic analysis of ripening berries showed that both light treatments up-regulated all the major anthocyanin structural genes, the key regulatory MYB transcription factors and abscisic acid (ABA) biosynthetic genes. However, higher induction of specific genes of anthocyanin and delphinidin biosynthesis alongside ABA signal perception and metabolism were found in red light. The difference in red and blue light signalling was found in 9-cis-epoxycarotenoid dioxygenase (NCED), ABA receptor pyrabactin resistance-like (PYL) and catabolic ABA-8'hydroxylase gene expression. Red light also up-regulated expression of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) domain transporters, which may indicate involvement of these proteins in vesicular trafficking of anthocyanins during fruit ripening. Our results suggest differential signal transduction and transport mechanisms between red and blue light in ABA-regulated anthocyanin and delphinidin biosynthesis during bilberry fruit ripening.
Collapse
Affiliation(s)
- Amos Samkumar
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Dan Jones
- The New Zealand Institute for Plant and Food Research Ltd., Auckland, New Zealand
| | - Katja Karppinen
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Andrew P Dare
- The New Zealand Institute for Plant and Food Research Ltd., Auckland, New Zealand
| | - Nina Sipari
- Viikki Metabolomics Unit, Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland
| | - Richard V Espley
- The New Zealand Institute for Plant and Food Research Ltd., Auckland, New Zealand
| | | | - Laura Jaakola
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
- Norwegian Institute of Bioeconomy Research, Ås, Norway
| |
Collapse
|
12
|
Jaiswal A, Gautam P, Pietilä EA, Timonen S, Nordström N, Akimov Y, Sipari N, Tanoli Z, Fleischer T, Lehti K, Wennerberg K, Aittokallio T. Multi-modal meta-analysis of cancer cell line omics profiles identifies ECHDC1 as a novel breast tumor suppressor. Mol Syst Biol 2021; 17:e9526. [PMID: 33750001 PMCID: PMC7983037 DOI: 10.15252/msb.20209526] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 02/17/2021] [Accepted: 02/19/2021] [Indexed: 12/12/2022] Open
Abstract
Molecular and functional profiling of cancer cell lines is subject to laboratory-specific experimental practices and data analysis protocols. The current challenge therefore is how to make an integrated use of the omics profiles of cancer cell lines for reliable biological discoveries. Here, we carried out a systematic analysis of nine types of data modalities using meta-analysis of 53 omics studies across 12 research laboratories for 2,018 cell lines. To account for a relatively low consistency observed for certain data modalities, we developed a robust data integration approach that identifies reproducible signals shared among multiple data modalities and studies. We demonstrated the power of the integrative analyses by identifying a novel driver gene, ECHDC1, with tumor suppressive role validated both in breast cancer cells and patient tumors. The multi-modal meta-analysis approach also identified synthetic lethal partners of cancer drivers, including a co-dependency of PTEN deficient endometrial cancer cells on RNA helicases.
Collapse
Affiliation(s)
- Alok Jaiswal
- Institute for Molecular Medicine Finland (FIMM)Helsinki Institute of Life Science (HiLIFE)University of HelsinkiHelsinkiFinland
- Present address:
The Broad Institute of MIT and HarvardCambridgeMAUSA
| | - Prson Gautam
- Institute for Molecular Medicine Finland (FIMM)Helsinki Institute of Life Science (HiLIFE)University of HelsinkiHelsinkiFinland
| | - Elina A Pietilä
- Individualized Drug Therapy, Research Programs UnitUniversity of HelsinkiHelsinkiFinland
| | - Sanna Timonen
- Institute for Molecular Medicine Finland (FIMM)Helsinki Institute of Life Science (HiLIFE)University of HelsinkiHelsinkiFinland
- Hematology Research Unit HelsinkiUniversity of Helsinki and Helsinki University Hospital Comprehensive Cancer CenterHelsinkiFinland
- Translational Immunology Research Program and Department of Clinical Chemistry and HematologyUniversity of HelsinkiHelsinkiFinland
| | - Nora Nordström
- Institute for Molecular Medicine Finland (FIMM)Helsinki Institute of Life Science (HiLIFE)University of HelsinkiHelsinkiFinland
| | - Yevhen Akimov
- Institute for Molecular Medicine Finland (FIMM)Helsinki Institute of Life Science (HiLIFE)University of HelsinkiHelsinkiFinland
| | - Nina Sipari
- Viikki Metabolomics UnitHelsinki Institute of Life Science (HiLIFE)University of HelsinkiHelsinkiFinland
| | - Ziaurrehman Tanoli
- Institute for Molecular Medicine Finland (FIMM)Helsinki Institute of Life Science (HiLIFE)University of HelsinkiHelsinkiFinland
| | - Thomas Fleischer
- Department of Cancer GeneticsInstitute for Cancer ResearchOslo University HospitalOsloNorway
| | - Kaisa Lehti
- Individualized Drug Therapy, Research Programs UnitUniversity of HelsinkiHelsinkiFinland
- Department of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
- Department of Biomedical Laboratory ScienceNorwegian University of Science and TechnologyTrondheimNorway
| | - Krister Wennerberg
- Institute for Molecular Medicine Finland (FIMM)Helsinki Institute of Life Science (HiLIFE)University of HelsinkiHelsinkiFinland
- Biotech Research & Innovation Centre (BRIC) and Novo Nordisk Foundation Center for Stem Cell Biology (DanStem)University of CopenhagenCopenhagenDenmark
| | - Tero Aittokallio
- Institute for Molecular Medicine Finland (FIMM)Helsinki Institute of Life Science (HiLIFE)University of HelsinkiHelsinkiFinland
- Department of Cancer GeneticsInstitute for Cancer ResearchOslo University HospitalOsloNorway
- Department of Mathematics and StatisticsUniversity of TurkuTurkuFinland
- Oslo Centre for Biostatistics and Epidemiology (OCBE)University of OsloOsloNorway
| |
Collapse
|
13
|
Levanova AA, Kalke KM, Lund LM, Sipari N, Sadeghi M, Nyman MC, Paavilainen H, Hukkanen V, Poranen MM. Enzymatically synthesized 2'-fluoro-modified Dicer-substrate siRNA swarms against herpes simplex virus demonstrate enhanced antiviral efficacy and low cytotoxicity. Antiviral Res 2020; 182:104916. [PMID: 32798603 PMCID: PMC7424292 DOI: 10.1016/j.antiviral.2020.104916] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 08/03/2020] [Accepted: 08/07/2020] [Indexed: 12/23/2022]
Abstract
Chemical modifications of small interfering (si)RNAs are used to enhance their stability and potency, and to reduce possible off-target effects, including immunogenicity. We have earlier introduced highly effective antiviral siRNA swarms against herpes simplex virus (HSV), targeting 653 bp of the essential UL29 viral gene. Here, we report a method for enzymatic production and antiviral use of 2′-fluoro-modified siRNA swarms. Utilizing the RNA-dependent RNA polymerase from bacteriophage phi6, we produced 2′-F-siRNA swarms containing either all or a fraction of modified adenosine, cytidine or uridine residues in the antisense strand of the UL29 target. The siRNA containing modified pyrimidines demonstrated high resistance to RNase A and the antiviral potency of all the UL29-specific 2′-F-siRNA swarms was 100-fold in comparison with the unmodified counterpart, without additional cytotoxicity. Modest stimulation of innate immunity signaling, including induced expression of both type I and type III interferons, as well as interferon-stimulated gene 54, by 2′-F-cytidine and 2′-F-uridine modified siRNA swarms occurred at early time points after transfection while the 2′-F-adenosine-containing siRNA was similar to the unmodified antiviral siRNA swarm in this respect. The antiviral efficacy of the 2′-F-siRNA swarms and the elicited cellular innate responses did not correlate suggesting that innate immunity pathways do not significantly contribute to the observed enhanced antiviral activity of the modified siRNAs. The results support further applications of enzymatically produced siRNA molecules with incorporated adenosine nucleotides, carrying fluoro-modification on ribose C2′ position, for further antiviral studies in vitro and in vivo. Phage phi6 polymerase can use 2′-F-dNTP substrates to produce 2′-F-modified dsRNA. SiRNAs containing 2′-F-modified pyrimidine nucleotides demonstrate resistance to RNase A. Enzymatically produced 2′-F-siRNA swarms display low cytotoxicity. Antiviral activity of 2′-F-siRNAs against HSV exceeds that of the unmodified siRNAs. Innate immunity induction by 2′-F-siRNAs is similar to that of unmodified siRNAs.
Collapse
Affiliation(s)
- Alesia A Levanova
- Molecular and Integrative Biosciences Research Programme, Biological and Environmental Sciences, University of Helsinki, Viikinkaari 9, FI-00014, Helsinki, Finland
| | - Kiira M Kalke
- Institute of Biomedicine, University of Turku, Turku, Finland
| | - Liisa M Lund
- Institute of Biomedicine, University of Turku, Turku, Finland
| | - Nina Sipari
- Viikki Metabolomics Unit, Organismal and Evolutionary Biology Research Programme, Biological and Environmental Sciences, University of Helsinki, Viikinkaari 5, FI-00014, Helsinki, Finland
| | | | - Marie C Nyman
- Institute of Biomedicine, University of Turku, Turku, Finland
| | | | - Veijo Hukkanen
- Institute of Biomedicine, University of Turku, Turku, Finland.
| | - Minna M Poranen
- Molecular and Integrative Biosciences Research Programme, Biological and Environmental Sciences, University of Helsinki, Viikinkaari 9, FI-00014, Helsinki, Finland.
| |
Collapse
|
14
|
Sipari N, Lihavainen J, Shapiguzov A, Kangasjärvi J, Keinänen M. Primary Metabolite Responses to Oxidative Stress in Early-Senescing and Paraquat Resistant Arabidopsis thaliana rcd1 (Radical-Induced Cell Death1). Front Plant Sci 2020; 11:194. [PMID: 32180786 PMCID: PMC7059619 DOI: 10.3389/fpls.2020.00194] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 02/10/2020] [Indexed: 05/04/2023]
Abstract
Rcd1 (radical-induced cell death1) is an Arabidopsis thaliana mutant, which exhibits high tolerance to paraquat [methyl viologen (MV)], herbicide that interrupts photosynthetic electron transport chain causing the formation of superoxide and inhibiting NADPH production in the chloroplast. To understand the biochemical mechanisms of MV-resistance and the role of RCD1 in oxidative stress responses, we performed metabolite profiling of wild type (Col-0) and rcd1 plants in light, after MV exposure and after prolonged darkness. The function of RCD1 has been extensively studied at transcriptomic and biochemical level, but comprehensive metabolite profiling of rcd1 mutant has not been conducted until now. The mutant plants exhibited very different metabolic features from the wild type under light conditions implying enhanced glycolytic activity, altered nitrogen and nucleotide metabolism. In light conditions, superoxide production was elevated in rcd1, but no metabolic markers of oxidative stress were detected. Elevated senescence-associated metabolite marker levels in rcd1 at early developmental stage were in line with its early-senescing phenotype and possible mitochondrial dysfunction. After MV exposure, a marked decline in the levels of glycolytic and TCA cycle intermediates in Col-0 suggested severe plastidic oxidative stress and inhibition of photosynthesis and respiration, whereas in rcd1 the results indicated sustained photosynthesis and respiration and induction of energy salvaging pathways. The accumulation of oxidative stress markers in both plant lines indicated that MV-resistance in rcd1 derived from the altered regulation of cellular metabolism and not from the restricted delivery of MV into the cells or chloroplasts. Considering the evidence from metabolomic, transcriptomic and biochemical studies, we propose that RCD1 has a negative effect on reductive metabolism and rerouting of the energy production pathways. Thus, the altered, highly active reductive metabolism, energy salvaging pathways and redox transfer between cellular compartments in rcd1 could be sufficient to avoid the negative effects of MV-induced toxicity.
Collapse
Affiliation(s)
- Nina Sipari
- Viikki Metabolomics Unit, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
- *Correspondence: Nina Sipari,
| | - Jenna Lihavainen
- Viikki Metabolomics Unit, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Alexey Shapiguzov
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia
| | - Jaakko Kangasjärvi
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Markku Keinänen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
| |
Collapse
|
15
|
Peivastegan B, Hadizadeh I, Nykyri J, Nielsen KL, Somervuo P, Sipari N, Tran C, Pirhonen M. Effect of wet storage conditions on potato tuber transcriptome, phytohormones and growth. BMC Plant Biol 2019; 19:262. [PMID: 31208336 PMCID: PMC6580497 DOI: 10.1186/s12870-019-1875-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 06/06/2019] [Indexed: 05/15/2023]
Abstract
BACKGROUND Stored potato (Solanum tuberosum L.) tubers are sensitive to wet conditions that can cause rotting in long-term storage. To study the effect of water on the tuber surface during storage, microarray analysis, RNA-Seq profiling, qRT-PCR and phytohormone measurements were performed to study gene expression and hormone content in wet tubers incubated at two temperatures: 4 °C and 15 °C. The growth of the plants was also observed in a greenhouse after the incubation of tubers in wet conditions. RESULTS Wet conditions induced a low-oxygen response, suggesting reduced oxygen availability in wet tubers at both temperatures when compared to that in the corresponding dry samples. Wet conditions induced genes coding for heat shock proteins, as well as proteins involved in fermentative energy production and defense against reactive oxygen species (ROS), which are transcripts that have been previously associated with low-oxygen stress in hypoxic or anoxic conditions. Wet treatment also induced senescence-related gene expression and genes involved in cell wall loosening, but downregulated genes encoding protease inhibitors and proteins involved in chloroplast functions and in the biosynthesis of secondary metabolites. Many genes involved in the production of phytohormones and signaling were also affected by wet conditions, suggesting altered regulation of growth by wet conditions. Hormone measurements after incubation showed increased salicylic acid (SA), abscisic acid (ABA) and auxin (IAA) concentrations as well as reduced production of jasmonate 12-oxo-phytodienoic acid (OPDA) in wet tubers. After incubation in wet conditions, the tubers produced fewer stems and more roots compared to controls incubated in dry conditions. CONCLUSIONS In wet conditions, tubers invest in ROS protection and defense against the abiotic stress caused by reduced oxygen due to excessive water. Changes in ABA, SA and IAA that are antagonistic to jasmonates affect growth and defenses, causing induction of root growth and rendering tubers susceptible to necrotrophic pathogens. Water on the tuber surface may function as a signal for growth, similar to germination of seeds.
Collapse
Affiliation(s)
- Bahram Peivastegan
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland
| | - Iman Hadizadeh
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland
| | - Johanna Nykyri
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland
| | | | - Panu Somervuo
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Nina Sipari
- Viikki Metabolomics Unit, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Cuong Tran
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland
- Present address: Department of Biology, Lund University, Lund, Sweden
| | - Minna Pirhonen
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland
| |
Collapse
|
16
|
Shapiguzov A, Vainonen JP, Hunter K, Tossavainen H, Tiwari A, Järvi S, Hellman M, Aarabi F, Alseekh S, Wybouw B, Van Der Kelen K, Nikkanen L, Krasensky-Wrzaczek J, Sipari N, Keinänen M, Tyystjärvi E, Rintamäki E, De Rybel B, Salojärvi J, Van Breusegem F, Fernie AR, Brosché M, Permi P, Aro EM, Wrzaczek M, Kangasjärvi J. Arabidopsis RCD1 coordinates chloroplast and mitochondrial functions through interaction with ANAC transcription factors. eLife 2019; 8:43284. [PMID: 30767893 PMCID: PMC6414205 DOI: 10.7554/elife.43284] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 02/14/2019] [Indexed: 01/17/2023] Open
Abstract
Reactive oxygen species (ROS)-dependent signaling pathways from chloroplasts and mitochondria merge at the nuclear protein RADICAL-INDUCED CELL DEATH1 (RCD1). RCD1 interacts in vivo and suppresses the activity of the transcription factors ANAC013 and ANAC017, which mediate a ROS-related retrograde signal originating from mitochondrial complex III. Inactivation of RCD1 leads to increased expression of mitochondrial dysfunction stimulon (MDS) genes regulated by ANAC013 and ANAC017. Accumulating MDS gene products, including alternative oxidases (AOXs), affect redox status of the chloroplasts, leading to changes in chloroplast ROS processing and increased protection of photosynthetic apparatus. ROS alter the abundance, thiol redox state and oligomerization of the RCD1 protein in vivo, providing feedback control on its function. RCD1-dependent regulation is linked to chloroplast signaling by 3'-phosphoadenosine 5'-phosphate (PAP). Thus, RCD1 integrates organellar signaling from chloroplasts and mitochondria to establish transcriptional control over the metabolic processes in both organelles. Most plant cells contain two types of compartments, the mitochondria and the chloroplasts, which work together to supply the chemical energy required by life processes. Genes located in another part of the cell, the nucleus, encode for the majority of the proteins found in these compartments. At any given time, the mitochondria and the chloroplasts send specific, ‘retrograde’ signals to the nucleus to turn on or off the genes they need. For example, mitochondria produce molecules known as reactive oxygen species (ROS) if they are having problems generating energy. These molecules activate several regulatory proteins that move into the nucleus and switch on MDS genes, a set of genes which helps to repair the mitochondria. Chloroplasts also produce ROS that can act as retrograde signals. It is still unclear how the nucleus integrates signals from both chloroplasts and mitochondria to ‘decide’ which genes to switch on, but a protein called RCD1 may play a role in this process. Indeed, previous studies have found that Arabidopsis plants that lack RCD1 have defects in both their mitochondria and chloroplasts. In these mutant plants, the MDS genes are constantly active and the chloroplasts have problems making ROS. To investigate this further, Shapiguzov, Vainonen et al. use biochemical and genetic approaches to study RCD1 in Arabidopsis. The experiments confirm that this protein allows a dialog to take place between the retrograde signals of both mitochondria and chloroplasts. On one hand, RCD1 binds to and inhibits the regulatory proteins that usually activate the MDS genes under the control of mitochondria. This explains why, in the absence of RCD1, the MDS genes are always active, which is ultimately disturbing how these compartments work. On the other hand, RCD1 is also found to be sensitive to the ROS that chloroplasts produce. This means that chloroplasts may be able to affect when mitochondria generate energy by regulating the protein. Finally, further experiments show that MDS genes can affect both mitochondria and chloroplasts: by influencing how these genes are regulated, RCD1 therefore acts on the two types of compartments. Overall, the work by Shapiguzov, Vainonen et al. describes a new way Arabidopsis coordinates its mitochondria and chloroplasts. Further studies will improve our understanding of how plants regulate these compartments in different environments to produce the energy they need. In practice, this may also help plant breeders create new varieties of crops that produce energy more efficiently and which better resist to stress.
Collapse
Affiliation(s)
- Alexey Shapiguzov
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Viikki Plant Science Center, University of Helsinki, Helsinki, Finland.,Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia
| | - Julia P Vainonen
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Viikki Plant Science Center, University of Helsinki, Helsinki, Finland
| | - Kerri Hunter
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Viikki Plant Science Center, University of Helsinki, Helsinki, Finland
| | - Helena Tossavainen
- Program in Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki, Helsinki, Finland.,Department of Chemistry, Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Arjun Tiwari
- Department of Biochemistry / Molecular Plant Biology, University of Turku, Turku, Finland
| | - Sari Järvi
- Department of Biochemistry / Molecular Plant Biology, University of Turku, Turku, Finland
| | - Maarit Hellman
- Department of Chemistry, Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Fayezeh Aarabi
- Max-Planck Institute for Molecular Plant Physiology, Potsdam, Germany
| | - Saleh Alseekh
- Max-Planck Institute for Molecular Plant Physiology, Potsdam, Germany.,Center of Plant System Biology and Biotechnology, Plovdiv, Bulgaria
| | - Brecht Wybouw
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Katrien Van Der Kelen
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Lauri Nikkanen
- Department of Biochemistry / Molecular Plant Biology, University of Turku, Turku, Finland
| | - Julia Krasensky-Wrzaczek
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Viikki Plant Science Center, University of Helsinki, Helsinki, Finland
| | - Nina Sipari
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Viikki Metabolomics Unit, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Markku Keinänen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
| | - Esa Tyystjärvi
- Department of Biochemistry / Molecular Plant Biology, University of Turku, Turku, Finland
| | - Eevi Rintamäki
- Department of Biochemistry / Molecular Plant Biology, University of Turku, Turku, Finland
| | - Bert De Rybel
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Jarkko Salojärvi
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Viikki Plant Science Center, University of Helsinki, Helsinki, Finland
| | - Frank Van Breusegem
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Alisdair R Fernie
- Max-Planck Institute for Molecular Plant Physiology, Potsdam, Germany.,Center of Plant System Biology and Biotechnology, Plovdiv, Bulgaria
| | - Mikael Brosché
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Viikki Plant Science Center, University of Helsinki, Helsinki, Finland.,Institute of Technology, University of Tartu, Tartu, Estonia
| | - Perttu Permi
- Program in Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki, Helsinki, Finland.,Department of Chemistry, Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland.,Department of Biological and Environmental Science, Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Eva-Mari Aro
- Department of Biochemistry / Molecular Plant Biology, University of Turku, Turku, Finland
| | - Michael Wrzaczek
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Viikki Plant Science Center, University of Helsinki, Helsinki, Finland
| | - Jaakko Kangasjärvi
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Viikki Plant Science Center, University of Helsinki, Helsinki, Finland
| |
Collapse
|
17
|
Dermadi D, Valo S, Ollila S, Soliymani R, Sipari N, Pussila M, Sarantaus L, Linden J, Baumann M, Nyström M. Western Diet Deregulates Bile Acid Homeostasis, Cell Proliferation, and Tumorigenesis in Colon. Cancer Res 2017; 77:3352-3363. [PMID: 28416481 DOI: 10.1158/0008-5472.can-16-2860] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 03/08/2017] [Accepted: 04/10/2017] [Indexed: 01/12/2023]
Abstract
Western-style diets (WD) high in fat and scarce in fiber and vitamin D increase risks of colorectal cancer. Here, we performed a long-term diet study in mice to follow tumorigenesis and characterize structural and metabolic changes in colon mucosa associated with WD and predisposition to colorectal cancer. WD increased colon tumor numbers, and mucosa proteomic analysis indicated severe deregulation of intracellular bile acid (BA) homeostasis and activation of cell proliferation. WD also increased crypt depth and colon cell proliferation. Despite increased luminal BA, colonocytes from WD-fed mice exhibited decreased expression of the BA transporters FABP6, OSTβ, and ASBT and decreased concentrations of secondary BA deoxycholic acid and lithocholic acid, indicating reduced activity of the nuclear BA receptor FXR. Overall, our results suggest that WD increases cancer risk by FXR inactivation, leading to BA deregulation and increased colon cell proliferation. Cancer Res; 77(12); 3352-63. ©2017 AACR.
Collapse
Affiliation(s)
- Denis Dermadi
- Department of Biosciences, Genetics, University of Helsinki, Helsinki, Finland. .,Laboratory of Immunology and Vascular Biology, Department of Pathology, Stanford University School of Medicine, Stanford, California.,The Center for Molecular Biology and Medicine, Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - Satu Valo
- Department of Biosciences, Genetics, University of Helsinki, Helsinki, Finland.,Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland
| | - Saara Ollila
- Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Rabah Soliymani
- Meilahti Clinical Proteomics Core Facility, Department of Biochemistry and Developmental Biology, Medicum, University of Helsinki, Helsinki, Finland
| | - Nina Sipari
- Viikki Metabolomics Unit, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Marjaana Pussila
- Department of Biosciences, Genetics, University of Helsinki, Helsinki, Finland
| | - Laura Sarantaus
- Department of Biosciences, Genetics, University of Helsinki, Helsinki, Finland
| | - Jere Linden
- Department of Basic Veterinary Sciences, University of Helsinki, Helsinki, Finland
| | - Marc Baumann
- Meilahti Clinical Proteomics Core Facility, Department of Biochemistry and Developmental Biology, Medicum, University of Helsinki, Helsinki, Finland
| | - Minna Nyström
- Department of Biosciences, Genetics, University of Helsinki, Helsinki, Finland.
| |
Collapse
|
18
|
Davidsson P, Broberg M, Kariola T, Sipari N, Pirhonen M, Palva ET. Short oligogalacturonides induce pathogen resistance-associated gene expression in Arabidopsis thaliana. BMC Plant Biol 2017; 17:19. [PMID: 28103793 PMCID: PMC5248502 DOI: 10.1186/s12870-016-0959-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 12/20/2016] [Indexed: 05/18/2023]
Abstract
BACKGROUND Oligogalacturonides (OGs) are important components of damage-associated molecular pattern (DAMP) signaling and influence growth regulation in plants. Recent studies have focused on the impact of long OGs (degree of polymerization (DP) from 10-15), demonstrating the induction of plant defense signaling resulting in enhanced defenses to necrotrophic pathogens. To clarify the role of trimers (trimeric OGs, DP3) in DAMP signaling and their impact on plant growth regulation, we performed a transcriptomic analysis through the RNA sequencing of Arabidopsis thaliana exposed to trimers. RESULTS The transcriptomic data from trimer-treated Arabidopsis seedlings indicate a clear activation of genes involved in defense signaling, phytohormone signaling and a down-regulation of genes involved in processes related to growth regulation and development. This is further accompanied with improved defenses against necrotrophic pathogens triggered by the trimer treatment, indicating that short OGs have a clear impact on plant responses, similar to those described for long OGs. CONCLUSIONS Our results demonstrate that trimers are indeed active elicitors of plant defenses. This is clearly indicated by the up-regulation of genes associated with plant defense signaling, accompanied with improved defenses against necrotrophic pathogens. Moreover, trimers simultaneously trigger a clear down-regulation of genes and gene sets associated with growth and development, leading to stunted seedling growth in Arabidopsis.
Collapse
Affiliation(s)
- Pär Davidsson
- Department of Biosciences, Division of Genetics, University of Helsinki, Helsinki, Finland
| | - Martin Broberg
- School of Biological Sciences, Bangor University, Bangor, Wales, UK
| | - Tarja Kariola
- Department of Biosciences, Division of Genetics, University of Helsinki, Helsinki, Finland
| | - Nina Sipari
- Department of Biosciences, Division of Genetics, University of Helsinki, Helsinki, Finland
| | - Minna Pirhonen
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland
| | - E Tapio Palva
- Department of Biosciences, Division of Genetics, University of Helsinki, Helsinki, Finland.
| |
Collapse
|
19
|
Survila M, Davidsson PR, Pennanen V, Kariola T, Broberg M, Sipari N, Heino P, Palva ET. Peroxidase-Generated Apoplastic ROS Impair Cuticle Integrity and Contribute to DAMP-Elicited Defenses. Front Plant Sci 2016; 7:1945. [PMID: 28066496 PMCID: PMC5179520 DOI: 10.3389/fpls.2016.01945] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 12/07/2016] [Indexed: 05/20/2023]
Abstract
Cuticular defects trigger a battery of reactions including enhanced reactive oxygen species (ROS) production and resistance to necrotrophic pathogens. However, the source of ROS generated by such impaired cuticles has remained elusive. Here, we report the characterization of Arabidopsis thaliana ohy1 mutant, a Peroxidase 57 (PER57) - overexpressing line that demonstrates enhanced defense responses that result both from increased accumulation of ROS and permeability of the leaf cuticle. The ohy1 mutant was identified in a screen of A. thaliana seedlings for oligogalacturonides (OGs) insensitive/hypersensitive mutants that exhibit altered growth retardation in response to exogenous OGs. Mutants impaired in OG sensitivity were analyzed for disease resistance/susceptibility to the necrotrophic phytopathogens Botrytis cinerea and Pectobacterium carotovorum. In the ohy1 line, the hypersensitivity to OGs was associated with resistance to the tested pathogens. This PER57 overexpressing line exhibited a significantly more permeable leaf cuticle than wild-type plants and this phenotype could be recapitulated by overexpressing other class III peroxidases. Such peroxidase overexpression was accompanied by the suppressed expression of cutin biosynthesis genes and the enhanced expression of genes associated with OG-signaling. Application of ABA completely removed ROS, restored the expression of genes associated with cuticle biosynthesis and led to decreased permeability of the leaf cuticle, and finally, abolished immunity to B. cinerea. Our work demonstrates that increased peroxidase activity increases permeability of the leaf cuticle. The loss of cuticle integrity primes plant defenses to necrotrophic pathogens via the activation of DAMP-responses.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Erkki T. Palva
- Division of Genetics, Viikki Plant Science Centre, Department of Biosciences, Faculty of Biological and Environmental Sciences, University of HelsinkiHelsinki, Finland
| |
Collapse
|
20
|
Leino TO, Johansson NG, Devisscher L, Sipari N, Yli-Kauhaluoma J, Wallén EAA. Synthesis of 1,3,6-Trisubstituted Azulenes Based on the 1-Acyloxyazulene Scaffold. European J Org Chem 2016. [DOI: 10.1002/ejoc.201600962] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Teppo O. Leino
- Division of Pharmaceutical Chemistry and Technology; Faculty of Pharmacy; University of Helsinki; Viikinkaari 5 E 00014 Helsinki Finland
| | - Niklas G. Johansson
- Division of Pharmaceutical Chemistry and Technology; Faculty of Pharmacy; University of Helsinki; Viikinkaari 5 E 00014 Helsinki Finland
| | - Lars Devisscher
- Division of Pharmaceutical Chemistry and Technology; Faculty of Pharmacy; University of Helsinki; Viikinkaari 5 E 00014 Helsinki Finland
| | - Nina Sipari
- Viikki Metabolomics Unit; Department of Biosciences; University of Helsinki; Viikinkaari 5 E 00014 Helsinki Finland
| | - Jari Yli-Kauhaluoma
- Division of Pharmaceutical Chemistry and Technology; Faculty of Pharmacy; University of Helsinki; Viikinkaari 5 E 00014 Helsinki Finland
| | - Erik A. A. Wallén
- Division of Pharmaceutical Chemistry and Technology; Faculty of Pharmacy; University of Helsinki; Viikinkaari 5 E 00014 Helsinki Finland
| |
Collapse
|
21
|
Siipola SM, Kotilainen T, Sipari N, Morales LO, Lindfors AV, Robson TM, Aphalo PJ. Epidermal UV-A absorbance and whole-leaf flavonoid composition in pea respond more to solar blue light than to solar UV radiation. Plant Cell Environ 2015; 38:941-52. [PMID: 25040832 DOI: 10.1111/pce.12403] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 06/26/2014] [Accepted: 06/29/2014] [Indexed: 05/20/2023]
Abstract
Plants synthesize phenolic compounds in response to certain environmental signals or stresses. One large group of phenolics, flavonoids, is considered particularly responsive to ultraviolet (UV) radiation. However, here we demonstrate that solar blue light stimulates flavonoid biosynthesis in the absence of UV-A and UV-B radiation. We grew pea plants (Pisum sativum cv. Meteor) outdoors, in Finland during the summer, under five types of filters differing in their spectral transmittance. These filters were used to (1) attenuate UV-B; (2) attenuate UV-B and UV-A < 370 nm; (3) attenuate UV-B and UV-A; (4) attenuate UV-B, UV-A and blue light; and (5) as a control not attenuating these wavebands. Attenuation of blue light significantly reduced the flavonoid content in leaf adaxial epidermis and reduced the whole-leaf concentrations of quercetin derivatives relative to kaempferol derivatives. In contrast, UV-B responses were not significant. These results show that pea plants regulate epidermal UV-A absorbance and accumulation of individual flavonoids by perceiving complex radiation signals that extend into the visible region of the solar spectrum. Furthermore, solar blue light instead of solar UV-B radiation can be the main regulator of phenolic compound accumulation in plants that germinate and develop outdoors.
Collapse
Affiliation(s)
- Sari M Siipola
- Plant Biology Division, Department of Biosciences, University of Helsinki, PO Box 56, Helsinki, 00014, Finland
| | | | | | | | | | | | | |
Collapse
|
22
|
Morales LO, Brosché M, Vainonen JP, Sipari N, Lindfors AV, Strid Å, Aphalo PJ. Are solar UV-B- and UV-A-dependent gene expression and metabolite accumulation in Arabidopsis mediated by the stress response regulator RADICAL-INDUCED CELL DEATH1? Plant Cell Environ 2015; 38:878-891. [PMID: 24689869 DOI: 10.1111/pce.12341] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 02/04/2014] [Accepted: 03/26/2014] [Indexed: 06/03/2023]
Abstract
Wavelengths in the ultraviolet (UV) region of the solar spectrum, UV-B (280-315 nm) and UV-A (315-400 nm), are key environmental signals modifying several aspects of plant physiology. Despite significant advances in the understanding of plant responses to UV-B and the identification of signalling components involved, there is limited information on the molecular mechanisms that control UV-B signalling in plants under natural sunlight. Here, we aimed to corroborate the previous suggested role for RADICAL-INDUCED CELL DEATH1 (RCD1) in UV-B signalling under full spectrum sunlight. Wild-type Arabidopsis thaliana and the rcd1-1 mutant were used in an experimental design outdoors where UV-B and UV-A irradiances were manipulated using plastic films, and gene expression, PYRIDOXINE BIOSYNTHESIS1 (PDX1) accumulation and metabolite profiles were analysed in the leaves. At the level of transcription, RCD1 was not directly involved in the solar UV-B regulation of genes with functions in UV acclimation, hormone signalling and stress-related markers. Furthermore, RCD1 had no role on PDX1 accumulation but modulated the UV-B induction of flavonoid accumulation in leaves of Arabidopsis exposed to solar UV. We conclude that RCD1 does not play an active role in UV-B signalling but rather modulates UV-B responses under full spectrum sunlight.
Collapse
Affiliation(s)
- Luis O Morales
- Division of Plant Biology, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland; School of Chemical Technology, Department of Forest Products Technology, Aalto University, FI-00076, Aalto, Finland
| | | | | | | | | | | | | |
Collapse
|
23
|
Piisilä M, Keceli MA, Brader G, Jakobson L, Jõesaar I, Sipari N, Kollist H, Palva ET, Kariola T. The F-box protein MAX2 contributes to resistance to bacterial phytopathogens in Arabidopsis thaliana. BMC Plant Biol 2015; 15:53. [PMID: 25849639 PMCID: PMC4340836 DOI: 10.1186/s12870-015-0434-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 01/21/2015] [Indexed: 05/18/2023]
Abstract
BACKGROUND The Arabidopsis thaliana F-box protein MORE AXILLARY GROWTH2 (MAX2) has previously been characterized for its role in plant development. MAX2 appears essential for the perception of the newly characterized phytohormone strigolactone, a negative regulator of polar auxin transport in Arabidopsis. RESULTS A reverse genetic screen for F-box protein mutants altered in their stress responses identified MAX2 as a component of plant defense. Here we show that MAX2 contributes to plant resistance against pathogenic bacteria. Interestingly, max2 mutant plants showed increased susceptibility to the bacterial necrotroph Pectobacterium carotovorum as well as to the hemi-biotroph Pseudomonas syringae but not to the fungal necrotroph Botrytis cinerea. max2 mutant phenotype was associated with constitutively increased stomatal conductance and decreased tolerance to apoplastic ROS but also with alterations in hormonal balance. CONCLUSIONS Our results suggest that MAX2 previously characterized for its role in regulation of polar auxin transport in Arabidopsis, and thus plant development also significantly influences plant disease resistance. We conclude that the increased susceptibility to P. syringae and P. carotovorum is due to increased stomatal conductance in max2 mutants promoting pathogen entry into the plant apoplast. Additional factors contributing to pathogen susceptibility in max2 plants include decreased tolerance to pathogen-triggered apoplastic ROS and alterations in hormonal signaling.
Collapse
Affiliation(s)
- Maria Piisilä
- />Division of Genetics, Department of Biosciences, Faculty of Biological & Environmental Sciences, University of Helsinki, Helsinki, FIN-00014 Finland
| | - Mehmet A Keceli
- />Division of Genetics, Department of Biosciences, Faculty of Biological & Environmental Sciences, University of Helsinki, Helsinki, FIN-00014 Finland
| | - Günter Brader
- />Austrian Institute of Technology GmbH, Bioresources, Health and Environment Department, Tulln an der Donau, 3430 Austria
| | - Liina Jakobson
- />Institute of Technology, University of Tartu, Nooruse 1, Tartu, 50411 Estonia
| | - Indrek Jõesaar
- />Institute of Technology, University of Tartu, Nooruse 1, Tartu, 50411 Estonia
| | - Nina Sipari
- />Division of Genetics, Department of Biosciences, Faculty of Biological & Environmental Sciences, University of Helsinki, Helsinki, FIN-00014 Finland
- />Viikki Metabolomics Unit, Department of Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, FIN-00014 Finland
| | - Hannes Kollist
- />Institute of Technology, University of Tartu, Nooruse 1, Tartu, 50411 Estonia
| | - E Tapio Palva
- />Division of Genetics, Department of Biosciences, Faculty of Biological & Environmental Sciences, University of Helsinki, Helsinki, FIN-00014 Finland
| | - Tarja Kariola
- />Division of Genetics, Department of Biosciences, Faculty of Biological & Environmental Sciences, University of Helsinki, Helsinki, FIN-00014 Finland
| |
Collapse
|
24
|
Brosché M, Blomster T, Salojärvi J, Cui F, Sipari N, Leppälä J, Lamminmäki A, Tomai G, Narayanasamy S, Reddy RA, Keinänen M, Overmyer K, Kangasjärvi J. Transcriptomics and functional genomics of ROS-induced cell death regulation by RADICAL-INDUCED CELL DEATH1. PLoS Genet 2014; 10:e1004112. [PMID: 24550736 PMCID: PMC3923667 DOI: 10.1371/journal.pgen.1004112] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 12/02/2013] [Indexed: 11/18/2022] Open
Abstract
Plant responses to changes in environmental conditions are mediated by a network of signaling events leading to downstream responses, including changes in gene expression and activation of cell death programs. Arabidopsis thaliana RADICAL-INDUCED CELL DEATH1 (RCD1) has been proposed to regulate plant stress responses by protein-protein interactions with transcription factors. Furthermore, the rcd1 mutant has defective control of cell death in response to apoplastic reactive oxygen species (ROS). Combining transcriptomic and functional genomics approaches we first used microarray analysis in a time series to study changes in gene expression after apoplastic ROS treatment in rcd1. To identify a core set of cell death regulated genes, RCD1-regulated genes were clustered together with other array experiments from plants undergoing cell death or treated with various pathogens, plant hormones or other chemicals. Subsequently, selected rcd1 double mutants were constructed to further define the genetic requirements for the execution of apoplastic ROS induced cell death. Through the genetic analysis we identified WRKY70 and SGT1b as cell death regulators functioning downstream of RCD1 and show that quantitative rather than qualitative differences in gene expression related to cell death appeared to better explain the outcome. Allocation of plant energy to defenses diverts resources from growth. Recently, a plant response termed stress-induced morphogenic response (SIMR) was proposed to regulate the balance between defense and growth. Using a rcd1 double mutant collection we show that SIMR is mostly independent of the classical plant defense signaling pathways and that the redox balance is involved in development of SIMR. Reactive oxygen species (ROS) are utilized in plants as signaling molecules to regulate development, stress responses and cell death. One extreme form of defense uses programmed cell death (PCD) in a scorched earth strategy to deliberately kill off cells invaded by a pathogen. Compared to animals, the regulation of plant PCD remains largely uncharacterized, particularly with regard to how ROS regulate changes in gene expression leading to PCD. Using comparative transcriptome analysis of mutants deficient in PCD regulation and publicly available cell death microarray data, we show that quantitative rather than qualitative differences in cell death gene expression appear to better explain the cell death response. In a genetic analysis with double mutants we also found the transcription factor WRKY70 and a component of ubiquitin mediated protein degradation, SGT1b, to be involved in regulation of ROS induced PCD.
Collapse
Affiliation(s)
- Mikael Brosché
- Division of Plant Biology, Department of Biosciences, University of Helsinki, Helsinki, Finland
- Institute of Technology, University of Tartu, Tartu, Estonia
- * E-mail:
| | - Tiina Blomster
- Division of Plant Biology, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Jarkko Salojärvi
- Division of Plant Biology, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Fuqiang Cui
- Division of Plant Biology, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Nina Sipari
- Department of Biology, University of Eastern Finland, Joensuu, Finland
| | - Johanna Leppälä
- Division of Plant Biology, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Airi Lamminmäki
- Division of Plant Biology, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Gloria Tomai
- Division of Plant Biology, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Shaman Narayanasamy
- Division of Plant Biology, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Ramesha A. Reddy
- Division of Plant Biology, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Markku Keinänen
- Department of Biology, University of Eastern Finland, Joensuu, Finland
| | - Kirk Overmyer
- Division of Plant Biology, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Jaakko Kangasjärvi
- Division of Plant Biology, Department of Biosciences, University of Helsinki, Helsinki, Finland
| |
Collapse
|
25
|
Cui F, Brosché M, Sipari N, Tang S, Overmyer K. Regulation of ABA dependent wound induced spreading cell death by MYB108. New Phytol 2013; 200:634-640. [PMID: 23952703 DOI: 10.1111/nph.12456] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Accepted: 07/18/2013] [Indexed: 05/20/2023]
Abstract
Wounding results in the controlled cell death of a few rows of cells adjacent to disrupted cells resulting in physical wound closure, which combined with phenolic compound deposition, prevents water loss and pathogen entry. The control of these processes remains uncharacterized. Cell death in a mutant of Arabidopsis thaliana lacking BOTRYTIS SENSITIVE1/MYB108 (BOS1/MYB108) function was characterized utilizing physiological, cell biological and genetic methods. The bos1 mutant has a wound induced runaway cell death that includes enhanced reactive oxygen species (ROS) production that followed the extent of enhanced cell death. Exogenous abscisic acid (ABA) enhanced wound induced cell death in Col-0 plants and was sufficient to trigger cell death in bos1. Uncontrolled cell death was dependent of the production and perception of ABA. Furthermore, bos1 had altered sensitivity to and accumulation of ABA. Arabidopsis possesses a genetic program controlling the extent of wound inducible cell death. BOS1 acts as a negative regulator of ABA induced cell death, which functions in the control of this wound sealing program. This program is distinct from other known cell death programs in that it is ABA dependent, but independent of salicylate biosynthesis, ethylene, jasmonate, metacaspases and ROS derived from RBOHD and RBOHF.
Collapse
Affiliation(s)
- Fuqiang Cui
- College of Biological Sciences, China Agricultural University, Beijing, 100193, China
- Division of Plant Biology, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
| | - Mikael Brosché
- Division of Plant Biology, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
- Institute of Technology, University of Tartu, Nooruse 1, Tartu, 50411, Estonia
| | - Nina Sipari
- Division of Plant Biology, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
| | - Saijun Tang
- College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Kirk Overmyer
- Division of Plant Biology, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
| |
Collapse
|
26
|
Karppinen K, Hirvelä E, Nevala T, Sipari N, Suokas M, Jaakola L. Changes in the abscisic acid levels and related gene expression during fruit development and ripening in bilberry (Vaccinium myrtillus L.). Phytochemistry 2013; 95:127-34. [PMID: 23850079 DOI: 10.1016/j.phytochem.2013.06.023] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 06/14/2013] [Accepted: 06/17/2013] [Indexed: 05/06/2023]
Abstract
Abscisic acid (ABA) is a natural plant hormone playing an important role in many physiological processes including fruit ripening and is also recently found to be potential for biomedical applications. This study was aimed to measure ABA levels and its biosynthesis in bilberry (Vaccinium myrtillus L.), which is one of the best sources of anthocyanins. Five ABA biosynthetic genes were isolated from bilberry and their expression profiles were studied in bilberry tissues, particularly during berry development. The level of ABA highly increased at the onset of bilberry fruit ripening, at the stage when expression of anthocyanin biosynthetic genes, chalcone synthase (VmCHS) and anthocyanidin synthase (VmANS), also increased. In fully ripe berries and leaves, ABA levels were lower but none was detected in bilberry stem or rhizome. The expression of 9-cis-epoxycarotenoid dioxygenase (VmNCED1) and putative neoxanthin synthase (VmNSY) was high in berry tissues and their expression increased markedly at the onset of berry ripening along with the accumulation of ABA. In contrast, the expression of zeaxanthin epoxidase (VmZEP), short-chain dehydrogenase/reductase (VmSDR/ABA2) and aldehyde oxidase (VmAO) were most highly associated with leaf tissues with no obvious relation to ABA content during berry development. The obtained results indicate that the ABA biosynthesis may play an important role in the regulation of ripening of non-climacteric bilberry fruits through transcriptional regulation of key ABA biosynthetic genes.
Collapse
Affiliation(s)
- Katja Karppinen
- Department of Biology, University of Oulu, P.O. Box 3000, FIN-90014 Oulu, Finland.
| | | | | | | | | | | |
Collapse
|
27
|
Li J, Besseau S, Törönen P, Sipari N, Kollist H, Holm L, Palva ET. Defense-related transcription factors WRKY70 and WRKY54 modulate osmotic stress tolerance by regulating stomatal aperture in Arabidopsis. New Phytol 2013; 200:457-472. [PMID: 23815736 PMCID: PMC4284015 DOI: 10.1111/nph.12378] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 05/21/2013] [Indexed: 05/20/2023]
Abstract
WRKY transcription factors (TFs) have been mainly associated with plant defense, but recent studies have suggested additional roles in the regulation of other physiological processes. Here, we explored the possible contribution of two related group III WRKY TFs, WRKY70 and WRKY54, to osmotic stress tolerance. These TFs are positive regulators of plant defense, and co-operate as negative regulators of salicylic acid (SA) biosynthesis and senescence. We employed single and double mutants of wrky54 and wrky70, as well as a WRKY70 overexpressor line, to explore the role of these TFs in osmotic stress (polyethylene glycol) responses. Their effect on gene expression was characterized by microarrays and verified by quantitative PCR. Stomatal phenotypes were assessed by water retention and stomatal conductance measurements. The wrky54wrky70 double mutants exhibited clearly enhanced tolerance to osmotic stress. However, gene expression analysis showed reduced induction of osmotic stress-responsive genes in addition to reduced accumulation of the osmoprotectant proline. By contrast, the enhanced tolerance was correlated with improved water retention and enhanced stomatal closure. These findings demonstrate that WRKY70 and WRKY54 co-operate as negative regulators of stomatal closure and, consequently, osmotic stress tolerance in Arabidopsis, suggesting that they have an important role, not only in plant defense, but also in abiotic stress signaling.
Collapse
Affiliation(s)
- Jing Li
- Viikki Biocenter, Division of Genetics, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
| | - Sebastien Besseau
- Université François Rabelais de Tours, EA2106 Biomolécules et Biotechnologies Végétales, 37200, Tours, France
| | - Petri Törönen
- Viikki Biocenter, Division of Genetics, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland
| | - Nina Sipari
- Viikki Biocenter, Division of Genetics, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
| | - Hannes Kollist
- Institute of Technology, University of Tartu, Nooruse 1, Tartu, 50411, Estonia
| | - Liisa Holm
- Viikki Biocenter, Division of Genetics, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland
| | - E Tapio Palva
- Viikki Biocenter, Division of Genetics, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
| |
Collapse
|
28
|
Morales LO, Brosché M, Vainonen J, Jenkins GI, Wargent JJ, Sipari N, Strid Å, Lindfors AV, Tegelberg R, Aphalo PJ. Multiple roles for UV RESISTANCE LOCUS8 in regulating gene expression and metabolite accumulation in Arabidopsis under solar ultraviolet radiation. Plant Physiol 2013; 161:744-59. [PMID: 23250626 PMCID: PMC3561016 DOI: 10.1104/pp.112.211375] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 12/17/2012] [Indexed: 05/18/2023]
Abstract
Photomorphogenic responses triggered by low fluence rates of ultraviolet B radiation (UV-B; 280-315 nm) are mediated by the UV-B photoreceptor UV RESISTANCE LOCUS8 (UVR8). Beyond our understanding of the molecular mechanisms of UV-B perception by UVR8, there is still limited information on how the UVR8 pathway functions under natural sunlight. Here, wild-type Arabidopsis (Arabidopsis thaliana) and the uvr8-2 mutant were used in an experiment outdoors where UV-A (315-400 nm) and UV-B irradiances were attenuated using plastic films. Gene expression, PYRIDOXINE BIOSYNTHESIS1 (PDX1) accumulation, and leaf metabolite signatures were analyzed. The results show that UVR8 is required for transcript accumulation of genes involved in UV protection, oxidative stress, hormone signal transduction, and defense against herbivores under solar UV. Under natural UV-A irradiance, UVR8 is likely to interact with UV-A/blue light signaling pathways to moderate UV-B-driven transcript and PDX1 accumulation. UVR8 both positively and negatively affects UV-A-regulated gene expression and metabolite accumulation but is required for the UV-B induction of phenolics. Moreover, UVR8-dependent UV-B acclimation during the early stages of plant development may enhance normal growth under long-term exposure to solar UV.
Collapse
Affiliation(s)
- Luis O Morales
- Division of Plant Biology, Department of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Blomster T, Salojärvi J, Sipari N, Brosché M, Ahlfors R, Keinänen M, Overmyer K, Kangasjärvi J. Apoplastic reactive oxygen species transiently decrease auxin signaling and cause stress-induced morphogenic response in Arabidopsis. Plant Physiol 2011; 157:1866-83. [PMID: 22007024 PMCID: PMC3327221 DOI: 10.1104/pp.111.181883] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 10/15/2011] [Indexed: 05/18/2023]
Abstract
Reactive oxygen species (ROS) are ubiquitous signaling molecules in plant stress and development. To gain further insight into the plant transcriptional response to apoplastic ROS, the phytotoxic atmospheric pollutant ozone was used as a model ROS inducer in Arabidopsis (Arabidopsis thaliana) and gene expression was analyzed with microarrays. In contrast to the increase in signaling via the stress hormones salicylic acid, abscisic acid, jasmonic acid (JA), and ethylene, ROS treatment caused auxin signaling to be transiently suppressed, which was confirmed with a DR5-uidA auxin reporter construct. Transcriptomic data revealed that various aspects of auxin homeostasis and signaling were modified by apoplastic ROS. Furthermore, a detailed analysis of auxin signaling showed that transcripts of several auxin receptors and Auxin/Indole-3-Acetic Acid (Aux/IAA) transcriptional repressors were reduced in response to apoplastic ROS. The ROS-derived changes in the expression of auxin signaling genes partially overlapped with abiotic stress, pathogen responses, and salicylic acid signaling. Several mechanisms known to suppress auxin signaling during biotic stress were excluded, indicating that ROS regulated auxin responses via a novel mechanism. Using mutants defective in various auxin (axr1, nit1, aux1, tir1 afb2, iaa28-1, iaa28-2) and JA (axr1, coi1-16) responses, ROS-induced cell death was found to be regulated by JA but not by auxin. Chronic ROS treatment resulted in altered leaf morphology, a stress response known as "stress-induced morphogenic response." Altered leaf shape of tir1 afb2 suggests that auxin was a negative regulator of stress-induced morphogenic response in the rosette.
Collapse
|
30
|
Trotta A, Wrzaczek M, Scharte J, Tikkanen M, Konert G, Rahikainen M, Holmström M, Hiltunen HM, Rips S, Sipari N, Mulo P, Weis E, von Schaewen A, Aro EM, Kangasjärvi S. Regulatory subunit B'gamma of protein phosphatase 2A prevents unnecessary defense reactions under low light in Arabidopsis. Plant Physiol 2011; 156:1464-80. [PMID: 21571669 PMCID: PMC3135915 DOI: 10.1104/pp.111.178442] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 05/11/2011] [Indexed: 05/19/2023]
Abstract
Light is an important environmental factor that modulates acclimation strategies and defense responses in plants. We explored the functional role of the regulatory subunit B'γ (B'γ) of protein phosphatase 2A (PP2A) in light-dependent stress responses of Arabidopsis (Arabidopsis thaliana). The predominant form of PP2A consists of catalytic subunit C, scaffold subunit A, and highly variable regulatory subunit B, which determines the substrate specificity of PP2A holoenzymes. Mutant leaves of knockdown pp2a-b'γ plants show disintegration of chloroplasts and premature yellowing conditionally under moderate light intensity. The cell-death phenotype is accompanied by the accumulation of hydrogen peroxide through a pathway that requires CONSTITUTIVE EXPRESSION OF PR GENES5 (CPR5). Moreover, the pp2a-b'γ cpr5 double mutant additionally displays growth suppression and malformed trichomes. Similar to cpr5, the pp2a-b'γ mutant shows constitutive activation of both salicylic acid- and jasmonic acid-dependent defense pathways. In contrast to cpr5, however, pp2a-b'γ leaves do not contain increased levels of salicylic acid or jasmonic acid. Rather, the constitutive defense response associates with hypomethylation of DNA and increased levels of methionine-salvage pathway components in pp2a-b'γ leaves. We suggest that the specific B'γ subunit of PP2A is functionally connected to CPR5 and operates in the basal repression of defense responses under low irradiance.
Collapse
|
31
|
Lepistö A, Kangasjärvi S, Luomala EM, Brader G, Sipari N, Keränen M, Keinänen M, Rintamäki E. Chloroplast NADPH-thioredoxin reductase interacts with photoperiodic development in Arabidopsis. Plant Physiol 2009; 149:1261-76. [PMID: 19151130 PMCID: PMC2649390 DOI: 10.1104/pp.108.133777] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 01/13/2009] [Indexed: 05/18/2023]
Abstract
Chloroplast NADPH-thioredoxin reductase (NTRC) belongs to the thioredoxin systems that control crucial metabolic and regulatory pathways in plants. Here, by characterization of T-DNA insertion lines of NTRC gene, we uncover a novel connection between chloroplast thiol redox regulation and the control of photoperiodic growth in Arabidopsis (Arabidopsis thaliana). Transcript and metabolite profiling revealed severe developmental and metabolic defects in ntrc plants grown under a short 8-h light period. Besides reduced chlorophyll and anthocyanin contents, ntrc plants showed alterations in the levels of amino acids and auxin. Furthermore, a low carbon assimilation rate of ntrc leaves was associated with enhanced transpiration and photorespiration. All of these characteristics of ntrc were less severe when plants were grown under a long 16-h photoperiod. Transcript profiling revealed that the mutant phenotypes of ntrc were accompanied by differential expression of genes involved in stomatal development, chlorophyll biosynthesis, chloroplast biogenesis, and circadian clock-linked light perception systems in ntrc plants. We propose that NTRC regulates several key processes, including chlorophyll biosynthesis and the shikimate pathway, in chloroplasts. In the absence of NTRC, imbalanced metabolic activities presumably modulate the chloroplast retrograde signals, leading to altered expression of nuclear genes and, ultimately, to the formation of the pleiotrophic phenotypes in ntrc mutant plants.
Collapse
Affiliation(s)
- Anna Lepistö
- Department of Biology, University of Turku, FI-20014 Turku, Finland
| | | | | | | | | | | | | | | |
Collapse
|