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Petutschnig E, Anders J, Stolze M, Meusel C, Hacke R, Much L, Schwier M, Gippert AL, Kroll S, Fasshauer P, Wiermer M, Lipka V. EXTRA LARGE G-PROTEIN2 mediates cell death and hyperimmunity in the chitin elicitor receptor kinase 1-4 mutant. Plant Physiol 2022; 189:2413-2431. [PMID: 35522044 PMCID: PMC9342992 DOI: 10.1093/plphys/kiac214] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 04/13/2022] [Indexed: 05/08/2023]
Abstract
Heterotrimeric G-proteins are signal transduction complexes that comprised three subunits, Gα, Gβ, and Gγ, and are involved in many aspects of plant life. The noncanonical Gα subunit EXTRA LARGE G-PROTEIN2 (XLG2) mediates pathogen-associated molecular pattern (PAMP)-induced reactive oxygen species (ROS) generation and immunity downstream of pattern recognition receptors. A mutant of the chitin receptor component CHITIN ELICITOR RECEPTOR KINASE1 (CERK1), cerk1-4, maintains normal chitin signaling capacity but shows excessive cell death upon infection with powdery mildew fungi. We identified XLG2 mutants as suppressors of the cerk1-4 phenotype. Mutations in XLG2 complex partners ARABIDOPSIS Gβ1 (AGB1) and Gγ1 (AGG1) have a partial cerk1-4 suppressor effect. Contrary to its role in PAMP-induced immunity, XLG2-mediated control of ROS production by RESPIRATORY BURST OXIDASE HOMOLOGUE D (RBOHD) is not critical for cerk1-4-associated cell death and hyperimmunity. The cerk1-4 phenotype is also independent of the co-receptor/adapter kinases BRI1-ASSOCIATED RECEPTOR KINASE 1 (BAK1) and SUPPRESSOR OF BIR1 1 (SOBIR1), but requires the E3 ubiquitin ligase PLANT U-BOX 2 (PUB2). XLG2 localizes to both the cell periphery and nucleus, and the cerk1-4 cell death phenotype is mediated by the cell periphery pool of XLG2. Integrity of the XLG2 N-terminal domain, but not its phosphorylation, is essential for correct XLG2 localization and formation of the cerk1-4 phenotype. Our results support a model in which XLG2 acts downstream of an unknown cell surface receptor that activates an NADPH oxidase-independent cell death pathway in Arabidopsis (Arabidopsis thaliana).
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Affiliation(s)
| | - Julia Anders
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Marnie Stolze
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Christopher Meusel
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Ronja Hacke
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Laura Much
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Melina Schwier
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Anna-Lena Gippert
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Samuel Kroll
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Patrick Fasshauer
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
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Waidmann S, Petutschnig E, Rozhon W, Molnár G, Popova O, Mechtler K, Jonak C. GSK3-mediated phosphorylation of DEK3 regulates chromatin accessibility and stress tolerance in Arabidopsis. FEBS J 2021; 289:473-493. [PMID: 34492159 DOI: 10.1111/febs.16186] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/19/2021] [Accepted: 09/06/2021] [Indexed: 12/18/2022]
Abstract
Chromatin dynamics enable the precise control of transcriptional programmes. The balance between restricting and opening of regulatory sequences on the DNA needs to be adjusted to prevailing conditions and is fine-tuned by chromatin remodelling proteins. DEK is an evolutionarily conserved chromatin architectural protein regulating important chromatin-related processes. However, the molecular link between DEK-induced chromatin reconfigurations and upstream signalling events remains unknown. Here, we show that ASKβ/AtSK31 is a salt stress-activated glycogen synthase kinase 3 (GSK3) from Arabidopsis thaliana that phosphorylates DEK3. This specific phosphorylation alters nuclear DEK3 protein complex composition and affects nucleosome occupancy and chromatin accessibility that is translated into changes in gene expression, contributing to salt stress tolerance. These findings reveal that DEK3 phosphorylation is critical for chromatin function and cellular stress response and provide a mechanistic example of how GSK3-based signalling is directly linked to chromatin, facilitating a transcriptional response.
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Affiliation(s)
- Sascha Waidmann
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Austria
| | - Elena Petutschnig
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Austria
| | - Wilfried Rozhon
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Austria
| | - Gergely Molnár
- AIT Austrian Institute of Technology, Center for Health & Bioresources, Tulln, Austria
| | - Olga Popova
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Austria
| | - Karl Mechtler
- Research Institute of Molecular Pathology, Vienna BioCenter, Austria
| | - Claudia Jonak
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Austria.,AIT Austrian Institute of Technology, Center for Health & Bioresources, Tulln, Austria
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Barghahn S, Arnal G, Jain N, Petutschnig E, Brumer H, Lipka V. Mixed Linkage β-1,3/1,4-Glucan Oligosaccharides Induce Defense Responses in Hordeum vulgare and Arabidopsis thaliana. Front Plant Sci 2021; 12:682439. [PMID: 34220903 PMCID: PMC8247929 DOI: 10.3389/fpls.2021.682439] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 05/25/2021] [Indexed: 05/06/2023]
Abstract
Plants detect conserved microbe-associated molecular patterns (MAMPs) and modified "self" molecules produced during pathogen infection [danger associated molecular patterns (DAMPs)] with plasma membrane-resident pattern recognition receptors (PRRs). PRR-mediated MAMP and/or DAMP perception activates signal transduction cascades, transcriptional reprogramming and plant immune responses collectively referred to as pattern-triggered immunity (PTI). Potential sources for MAMPs and DAMPs are microbial and plant cell walls, which are complex extracellular matrices composed of different carbohydrates and glycoproteins. Mixed linkage β-1,3/1,4-glucan (β-1,3/1,4-MLG) oligosaccharides are abundant components of monocot plant cell walls and are present in symbiotic, pathogenic and apathogenic fungi, oomycetes and bacteria, but have not been detected in the cell walls of dicot plant species so far. Here, we provide evidence that the monocot crop plant H. vulgare and the dicot A. thaliana can perceive β-1,3/1,4-MLG oligosaccharides and react with prototypical PTI responses. A collection of Arabidopsis innate immunity signaling mutants and >100 Arabidopsis ecotypes showed unaltered responses upon treatment with β-1,3/1,4-MLG oligosaccharides suggesting the employment of a so far unknown and highly conserved perception machinery. In conclusion, we postulate that β-1,3/1,4-MLG oligosaccharides have the dual capacity to act as immune-active DAMPs and/or MAMPs in monocot and dicot plant species.
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Affiliation(s)
- Sina Barghahn
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute of Plant Sciences, The University of Göttingen, Göttingen, Germany
| | - Gregory Arnal
- Michael Smith Laboratories, The University of British Columbia, Vancouver, BC, Canada
| | - Namrata Jain
- Michael Smith Laboratories, The University of British Columbia, Vancouver, BC, Canada
| | - Elena Petutschnig
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute of Plant Sciences, The University of Göttingen, Göttingen, Germany
| | - Harry Brumer
- Michael Smith Laboratories, The University of British Columbia, Vancouver, BC, Canada
- Department of Chemistry, The University of British Columbia, Vancouver, BC, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada
- Department of Botany, The University of British Columbia, Vancouver, BC, Canada
| | - Volker Lipka
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute of Plant Sciences, The University of Göttingen, Göttingen, Germany
- *Correspondence: Volker Lipka,
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Erwig J, Ghareeb H, Kopischke M, Hacke R, Matei A, Petutschnig E, Lipka V. Chitin-induced and CHITIN ELICITOR RECEPTOR KINASE1 (CERK1) phosphorylation-dependent endocytosis of Arabidopsis thaliana LYSIN MOTIF-CONTAINING RECEPTOR-LIKE KINASE5 (LYK5). New Phytol 2017; 215:382-396. [PMID: 28513921 DOI: 10.1111/nph.14592] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [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: 12/12/2016] [Accepted: 03/23/2017] [Indexed: 05/21/2023]
Abstract
To detect potential pathogens, plants perceive the fungal polysaccharide chitin through receptor complexes containing lysin motif receptor-like kinases (LysM-RLKs). To investigate the ligand-induced spatial dynamics of chitin receptor components, we studied the subcellular behaviour of two Arabidopsis thaliana LysM-RLKs involved in chitin signalling, CHITIN ELICITOR RECEPTOR KINASE1 (CERK1) and LYSIN MOTIF-CONTAINING RECEPTOR-LIKE KINASE5. We performed standard and quantitative confocal laser scanning microscopy on stably transformed A. thaliana plants expressing fluorescently tagged CERK1 and LYK5 from their native promoters. Microscopy approaches were complemented by biochemical analyses in plants and in vitro. Both CERK1 and LYK5 localized to the plasma membrane and showed constitutive endomembrane trafficking. After chitin treatment, however, CERK1 remained at the plasma membrane while LYK5 relocalized into mobile intracellular vesicles. Detailed analyses revealed that chitin perception transiently induced the internalization of LYK5 into late endocytic compartments. Plants that lacked CERK1 or expressed an enzymatically inactive CERK1 variant did not exhibit chitin-induced endocytosis of LYK5. CERK1 could phosphorylate LYK5 in vitro and chitin treatment induced CERK1-dependent phosphorylation of LYK5 in planta. Our results suggest that chitin-induced phosphorylation by CERK1 triggers LYK5 internalization. Thus, our work identifies phosphorylation as a key regulatory step in endocytosis of plant RLKs and also provides evidence for receptor complex dissociation after ligand perception.
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Affiliation(s)
- Jan Erwig
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
| | - Hassan Ghareeb
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
- Department of Plant Biotechnology, National Research Centre, El Buhouth St, Dokki, Cairo, Egypt
| | - Michaela Kopischke
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
| | - Ronja Hacke
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
| | - Alexandra Matei
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
| | - Elena Petutschnig
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
| | - Volker Lipka
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
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Rozhon W, Wang W, Berthiller F, Mayerhofer J, Chen T, Petutschnig E, Sieberer T, Poppenberger B, Jonak C. Bikinin-like inhibitors targeting GSK3/Shaggy-like kinases: characterisation of novel compounds and elucidation of their catabolism in planta. BMC Plant Biol 2014; 14:172. [PMID: 24947596 PMCID: PMC4078015 DOI: 10.1186/1471-2229-14-172] [Citation(s) in RCA: 9] [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: 01/15/2014] [Accepted: 06/17/2014] [Indexed: 05/08/2023]
Abstract
BACKGROUND Plant GSK-3/Shaggy-like kinases are key players in brassinosteroid (BR) signalling which impact on plant development and participate in response to wounding, pathogens and salt stress. Bikinin was previously identified in a chemical genetics screen as an inhibitor targeting these kinases. To dissect the structural elements crucial for inhibition of GSK-3/Shaggy-like kinases by bikinin and to isolate more potent compounds we synthesised a number of related substances and tested their inhibitory activity in vitro and in vivo using Arabidopsis thaliana. RESULTS A pyridine ring with an amido succinic acid residue in position 2 and a halogen in position 5 were crucial for inhibitory activity. The compound with an iodine substituent in position 5, denoted iodobikinin, was most active in inhibiting BIN2 activity in vitro and efficiently induced brassinosteroid-like responses in vivo. Its methyl ester, methyliodobikinin, showed improved cell permeability, making it highly potent in vivo although it had lower activity in vitro. HPLC analysis revealed that the methyl residue was rapidly cleaved off in planta liberating active iodobikinin. In addition, we provide evidence that iodobikinin and bikinin are inactivated in planta by conjugation with glutamic acid or malic acid and that the latter process is catalysed by the malate transferase SNG1. CONCLUSION Brassinosteroids participate in regulation of many aspects of plant development and in responses to environmental cues. Thus compounds modulating their action are valuable tools to study such processes and may be an interesting opportunity to modify plant growth and performance in horticulture and agronomy. Here we report the development of bikinin derivatives with increased potency that can activate BR signalling and mimic BR action. Methyliodobikinin was 3.4 times more active in vivo than bikinin. The main reason for the superior activity of methyliodobikinin, the most potent compound, is its enhanced plant tissue permeability. Inactivation of bikinin and its derivatives in planta involves SNG1, which constitutes a novel pathway for modification of xenobiotic compounds.
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Affiliation(s)
- Wilfried Rozhon
- GMI-Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna Biocenter, Dr. Bohr-Gasse 3, Vienna 1030, Austria
- Biotechnology of Horticultural Crops, Technische Universität München, Liesel-Beckmann-Straße 1, Freising 85354, Germany
- Max F. Perutz Laboratories, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna 1030, Austria
| | - Wuyan Wang
- Biotechnology of Horticultural Crops, Technische Universität München, Liesel-Beckmann-Straße 1, Freising 85354, Germany
- Present address: Plant Biochemistry, ETH Zürich, Universitätsstr. 2, Zürich 8092, Switzerland
| | - Franz Berthiller
- Center for Analytical Chemistry, Department of Agrobiotechnology, University of Natural Resources and Life Sciences, Konrad Lorenz Straße 20, Tulln 3430, Austria
| | - Juliane Mayerhofer
- GMI-Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna Biocenter, Dr. Bohr-Gasse 3, Vienna 1030, Austria
| | - Tingting Chen
- Biotechnology of Horticultural Crops, Technische Universität München, Liesel-Beckmann-Straße 1, Freising 85354, Germany
| | - Elena Petutschnig
- GMI-Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna Biocenter, Dr. Bohr-Gasse 3, Vienna 1030, Austria
- Present address: Albrecht-von-Haller-Institute of Plant Sciences, Department of Plant Cell Biology, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, Göttingen 37077, Germany
| | - Tobias Sieberer
- Max F. Perutz Laboratories, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna 1030, Austria
- Department of Plant Sciences, Research Unit Plant Growth Regulation, Technische Universität München, Liesel-Beckmann-Straße 1, Freising-Weihenstephan 85354, Germany
| | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, Technische Universität München, Liesel-Beckmann-Straße 1, Freising 85354, Germany
- Max F. Perutz Laboratories, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna 1030, Austria
| | - Claudia Jonak
- GMI-Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna Biocenter, Dr. Bohr-Gasse 3, Vienna 1030, Austria
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Dal Santo S, Stampfl H, Krasensky J, Kempa S, Gibon Y, Petutschnig E, Rozhon W, Heuck A, Clausen T, Jonak C. Stress-induced GSK3 regulates the redox stress response by phosphorylating glucose-6-phosphate dehydrogenase in Arabidopsis. Plant Cell 2012; 24:3380-92. [PMID: 22885737 PMCID: PMC3462638 DOI: 10.1105/tpc.112.101279] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 07/06/2012] [Accepted: 07/12/2012] [Indexed: 05/19/2023]
Abstract
Diverse stresses such as high salt conditions cause an increase in reactive oxygen species (ROS), necessitating a redox stress response. However, little is known about the signaling pathways that regulate the antioxidant system to counteract oxidative stress. Here, we show that a Glycogen Synthase Kinase3 from Arabidopsis thaliana (ASKα) regulates stress tolerance by activating Glc-6-phosphate dehydrogenase (G6PD), which is essential for maintaining the cellular redox balance. Loss of stress-activated ASKα leads to reduced G6PD activity, elevated levels of ROS, and enhanced sensitivity to salt stress. Conversely, plants overexpressing ASKα have increased G6PD activity and low levels of ROS in response to stress and are more tolerant to salt stress. ASKα stimulates the activity of a specific cytosolic G6PD isoform by phosphorylating the evolutionarily conserved Thr-467, which is implicated in cosubstrate binding. Our results reveal a novel mechanism of G6PD adaptive regulation that is critical for the cellular stress response.
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Affiliation(s)
- Silvia Dal Santo
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Hansjörg Stampfl
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Julia Krasensky
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Stefan Kempa
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Yves Gibon
- Institut National de la Recherche Agronomique-Bordeaux, La Grande Ferrade, 33883 Villenave d’Ornon, France
| | - Elena Petutschnig
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Wilfried Rozhon
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Alexander Heuck
- Research Institute of Molecular Pathology, 1030 Vienna, Austria
| | - Tim Clausen
- Research Institute of Molecular Pathology, 1030 Vienna, Austria
| | - Claudia Jonak
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Vienna, Austria
- Address correspondence to
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Jacobs S, Zechmann B, Molitor A, Trujillo M, Petutschnig E, Lipka V, Kogel KH, Schäfer P. Broad-spectrum suppression of innate immunity is required for colonization of Arabidopsis roots by the fungus Piriformospora indica. Plant Physiol 2011; 157. [PMID: 21474434 PMCID: PMC3165898 DOI: 10.1104/pp.111.900420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Piriformospora indica is a root-colonizing basidiomycete that confers a wide range of beneficial traits to its host. The fungus shows a biotrophic growth phase in Arabidopsis (Arabidopsis thaliana) roots followed by a cell death-associated colonization phase, a colonization strategy that, to our knowledge, has not yet been reported for this plant. P. indica has evolved an extraordinary capacity for plant root colonization. Its broad host spectrum encompasses gymnosperms and monocotyledonous as well as dicotyledonous angiosperms, which suggests that it has an effective mechanism(s) for bypassing or suppressing host immunity. The results of our work argue that P. indica is confronted with a functional root immune system. Moreover, the fungus does not evade detection but rather suppresses immunity triggered by various microbe-associated molecular patterns. This ability to suppress host immunity is compromised in the jasmonate mutants jasmonate insensitive1-1 and jasmonate resistant1-1. A quintuple-DELLA mutant displaying constitutive gibberellin (GA) responses and the GA biosynthesis mutant ga1-6 (for GA requiring 1) showed higher and lower degrees of colonization, respectively, in the cell death-associated stage, suggesting that P. indica recruits GA signaling to help establish proapoptotic root cell colonization. Our study demonstrates that mutualists, like pathogens, are confronted with an effective innate immune system in roots and that colonization success essentially depends on the evolution of strategies for immunosuppression.
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Affiliation(s)
- Sophie Jacobs
- Research Centre for Biosystems, Land Use, and Nutrition, Justus Liebig University, D-35392 Giessen, Germany
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8
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Jacobs S, Zechmann B, Molitor A, Trujillo M, Petutschnig E, Lipka V, Kogel KH, Schäfer P. Broad-spectrum suppression of innate immunity is required for colonization of Arabidopsis roots by the fungus Piriformospora indica. Plant Physiol 2011; 156:726-40. [PMID: 21474434 PMCID: PMC3177271 DOI: 10.1104/pp.111.176446] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 04/04/2011] [Indexed: 05/18/2023]
Abstract
Piriformospora indica is a root-colonizing basidiomycete that confers a wide range of beneficial traits to its host. The fungus shows a biotrophic growth phase in Arabidopsis (Arabidopsis thaliana) roots followed by a cell death-associated colonization phase, a colonization strategy that, to our knowledge, has not yet been reported for this plant. P. indica has evolved an extraordinary capacity for plant root colonization. Its broad host spectrum encompasses gymnosperms and monocotyledonous as well as dicotyledonous angiosperms, which suggests that it has an effective mechanism(s) for bypassing or suppressing host immunity. The results of our work argue that P. indica is confronted with a functional root immune system. Moreover, the fungus does not evade detection but rather suppresses immunity triggered by various microbe-associated molecular patterns. This ability to suppress host immunity is compromised in the jasmonate mutants jasmonate insensitive1-1 and jasmonate resistant1-1. A quintuple-DELLA mutant displaying constitutive gibberellin (GA) responses and the GA biosynthesis mutant ga1-6 (for GA requiring 1) showed higher and lower degrees of colonization, respectively, in the cell death-associated stage, suggesting that P. indica recruits GA signaling to help establish proapoptotic root cell colonization. Our study demonstrates that mutualists, like pathogens, are confronted with an effective innate immune system in roots and that colonization success essentially depends on the evolution of strategies for immunosuppression.
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Rozhon W, Khan M, Petutschnig E, Poppenberger B. Identification of cis- and trans-acting elements in pHW126, a representative of a novel group of rolling circle plasmids. Plasmid 2010; 65:70-6. [PMID: 20854841 DOI: 10.1016/j.plasmid.2010.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 09/13/2010] [Accepted: 09/14/2010] [Indexed: 10/19/2022]
Abstract
pHW126, pIGRK, pIGMS31 and pRAO1 are the only known members of a novel and as yet uncharacterised family of rolling circle plasmids. pHW126 contains only two open reading frames, of which one shows homology to pMV158-family mobilisation proteins. Here we provide evidence that the second open reading frame encodes a replication protein (Rep). Mutation or deletion of this gene resulted in replication deficient constructs, but providing functional Rep from a compatible vector rescued these constructs, indicating that Rep acts in trans. An approximately 300 bp cis-acting region representing the origin of replication was identified upstream of the rep gene. The origin was identified to be composed of three parts: an accessory region, a conserved stretch and four perfect tandem repeats. The two latter elements were essential for replication. Constructs with a deletion of the accessory region could still replicate, but their loss rate was high, indicating that the accessory region is necessary for plasmid maintenance under non-selective conditions. Interestingly, pHW126 could replicate in all Enterobacteriaceae tested while Agrobacterium tumefaciens and Pseudomonas syringae were inappropriate hosts. Thus, pHW126 seems to have a rather limited host range.
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Affiliation(s)
- Wilfried Rozhon
- Max F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9, 1030 Vienna, Austria.
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Rozhon W, Mayerhofer J, Petutschnig E, Fujioka S, Jonak C. ASKtheta, a group-III Arabidopsis GSK3, functions in the brassinosteroid signalling pathway. Plant J 2010; 62:215-23. [PMID: 20128883 PMCID: PMC2881309 DOI: 10.1111/j.1365-313x.2010.04145.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [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: 07/16/2009] [Revised: 12/11/2009] [Accepted: 12/23/2009] [Indexed: 05/18/2023]
Abstract
Brassinosteroids (BRs) are plant hormones that regulate many processes including cell elongation, leaf development, pollen tube growth and xylem differentiation. GSK3/shaggy-like kinases (GSK) are critical regulators of intracellular signalling initiated by the binding of BR to the BRI1 receptor complex. Three GSKs have already been shown to relay BR responses, including phosphorylation of the transcriptional regulator BES1. However, recent studies indicate that one or more yet unidentified protein kinases are involved in BR signalling. Here, we show that the in vivo protein kinase activity of the group-III GSK, ASKtheta, was negatively regulated by BRI1. Arabidopsis thaliana plants with enhanced ASKtheta activity displayed a bri1-like phenotype. ASKtheta overexpressors accumulated high levels of brassinolide, castasterone and typhasterol, and were insensitive to BR. ASKtheta localized to the nucleus and directly phosphorylated BES1 and BZR1. Moreover, the BES1/BZR1-like transcription factor BEH2 was isolated as an ASKtheta interaction partner in a yeast two-hybrid screen. ASKtheta phosphorylated BEH2 both in vitro and in vivo. Overall, these data provide strong evidence that ASKtheta is a novel component of the BR signalling cascade, targeting the transcription factors BES1, BZR1 and BEH2.
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Affiliation(s)
- Wilfried Rozhon
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of SciencesDr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Juliane Mayerhofer
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of SciencesDr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Elena Petutschnig
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of SciencesDr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Shozo Fujioka
- RIKEN Advanced Science Institute, Wako-shiSaitama 351–0198, Japan
| | - Claudia Jonak
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of SciencesDr. Bohr-Gasse 3, 1030 Vienna, Austria
- *For correspondence (fax +43 1 79044 23 9850; e-mail )
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Rozhon W, Petutschnig E, Khan M, Summers DK, Poppenberger B. Frequency and diversity of small cryptic plasmids in the genus Rahnella. BMC Microbiol 2010; 10:56. [PMID: 20170524 PMCID: PMC2831885 DOI: 10.1186/1471-2180-10-56] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Accepted: 02/19/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rahnella is a widely distributed genus belonging to the Enterobacteriaceae and frequently present on vegetables. Although Rahnella has interesting agro-economical and industrial properties and several strains possess antibiotic resistances and toxin genes which might spread within microbial communities, little is known about plasmids of this genus. Thus, we isolated a number of Rahnella strains and investigated their complements of small plasmids. RESULTS In total 53 strains were investigated and 11 plasmids observed. Seven belonged to the ColE1 family; one was ColE2-like and three shared homology to rolling circle plasmids. One of them belonged to the pC194/pUB110 family and two showed similarity to poorly characterised plasmid groups. The G+C content of two rolling circle plasmids deviated considerably from that of Rahnella, indicating that their usual hosts might belong to other genera. Most ColE1-like plasmids formed a subgroup within the ColE1 family that seems to be fairly specific for Rahnella. Intriguingly, the multimer resolution sites of all ColE1-like plasmids had the same orientation with respect to the origin of replication. This arrangement might be necessary to prevent inappropriate synthesis of a small regulatory RNA that regulates cell division. Although the ColE1-like plasmids did not possess any mobilisation system, they shared large parts with high sequence identity in coding and non-coding regions. In addition, highly homologous regions of plasmids isolated from Rahnella and the chromosomes of Erwinia tasmaniensis and Photorhabdus luminescens could be identified. CONCLUSIONS For the genus Rahnella we observed plasmid-containing isolates at a frequency of 19%, which is in the average range for Enterobacteriaceae. These plasmids belonged to different groups with members of the ColE1-family most frequently found. Regions of striking sequence homology of plasmids and bacterial chromosomes highlight the importance of plasmids for lateral gene transfer (including chromosomal sequences) to distinct genera.
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Affiliation(s)
- Wilfried Rozhon
- Max F Perutz Laboratories, University of Vienna, Dr Bohrgasse 9, Vienna, Austria.
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Lipka U, Fuchs R, Kuhns C, Petutschnig E, Lipka V. Live and let die – Arabidopsis nonhost resistance to powdery mildews. Eur J Cell Biol 2010; 89:194-9. [DOI: 10.1016/j.ejcb.2009.11.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Gimenez-Ibanez S, Hann DR, Ntoukakis V, Petutschnig E, Lipka V, Rathjen JP. AvrPtoB Targets the LysM Receptor Kinase CERK1 to Promote Bacterial Virulence on Plants. Curr Biol 2009; 19:423-9. [DOI: 10.1016/j.cub.2009.01.054] [Citation(s) in RCA: 269] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Revised: 01/14/2009] [Accepted: 01/19/2009] [Indexed: 12/26/2022]
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Rozhon W, Petutschnig E, Wrzaczek M, Jonak C. Quantification of free and total salicylic acid in plants by solid-phase extraction and isocratic high-performance anion-exchange chromatography. Anal Bioanal Chem 2005; 382:1620-7. [PMID: 15997378 DOI: 10.1007/s00216-005-3326-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2005] [Revised: 04/29/2005] [Accepted: 05/08/2005] [Indexed: 10/25/2022]
Abstract
Salicylic acid (SA) is an important signaling compound in plants and is involved in various defense responses. Here we report a new method for quantification of free and total soluble SA in Arabidopsis thaliana with 5-fluorosalicylic acid (5-FSA) as internal standard. The SA was isolated from leaf extracts by solid-phase extraction with phenyl-phase cartridges and selectively eluted as the cationic iron(III)-complex. Recoveries of SA and 5-FSA were equal and exceeded 90%. Free SA was subsequently released from the iron(III)-complex by addition of 2,2'-bipyridyl and high-performance anion-exchange chromatography was performed on an NH2 column. The SA appeared as last peak with a retention time of 15 min, baseline-separated from other substances. On-line detection was performed fluorimetrically for both SA and 5-FSA at an excitation wavelength of 300 nm and an emission wavelength of 410 nm, because both substances give similar fluorescence spectra. The detection limit for SA was 5 ng g(-1) FW for a sample size of 100 mg. Thus the main advantages of the method are highly selective sample preparation, increased sensitivity, reduced analysis time compared with reversed-phase HPLC, and use of a novel internal standard detectable under the same conditions as SA. The techniques described are applicable to other plant materials.
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Affiliation(s)
- Wilfried Rozhon
- Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Dr. Bohrgasse 9, 1030, Vienna, Austria.
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