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Rübsam H, Krönauer C, Abel NB, Ji H, Lironi D, Hansen SB, Nadzieja M, Kolte MV, Abel D, de Jong N, Madsen LH, Liu H, Stougaard J, Radutoiu S, Andersen KR. Nanobody-driven signaling reveals the core receptor complex in root nodule symbiosis. Science 2023; 379:272-277. [PMID: 36656954 DOI: 10.1126/science.ade9204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Understanding the composition and activation of multicomponent receptor complexes is a challenge in biology. To address this, we developed a synthetic approach based on nanobodies to drive assembly and activation of cell surface receptors and apply the concept by manipulating receptors that govern plant symbiosis with nitrogen-fixing bacteria. We show that the Lotus japonicus Nod factor receptors NFR1 and NFR5 constitute the core receptor complex initiating the cortical root nodule organogenesis program as well as the epidermal program controlling infection. We find that organogenesis signaling is mediated by the intracellular kinase domains whereas infection requires functional ectodomains. Finally, we identify evolutionarily distant barley receptors that activate root nodule organogenesis, which could enable engineering of biological nitrogen-fixation into cereals.
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Affiliation(s)
- Henriette Rübsam
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Christina Krönauer
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Nikolaj B Abel
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Hongtao Ji
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark.,National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Damiano Lironi
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Simon B Hansen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Marcin Nadzieja
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Marie V Kolte
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Dörte Abel
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Noor de Jong
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Lene H Madsen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Huijun Liu
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Jens Stougaard
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Simona Radutoiu
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Kasper R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
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Krönauer C, Lahaye T. The flavin monooxygenase Bs3 triggers cell death in plants, impairs growth in yeast and produces H2O2 in vitro. PLoS One 2021; 16:e0256217. [PMID: 34411175 PMCID: PMC8375990 DOI: 10.1371/journal.pone.0256217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 04/23/2021] [Accepted: 08/02/2021] [Indexed: 11/18/2022] Open
Abstract
The pepper resistance gene Bs3 triggers a hypersensitive response (HR) upon transcriptional activation by the corresponding effector protein AvrBs3 from the bacterial pathogen Xanthomonas. Expression of Bs3 in yeast inhibited proliferation, demonstrating that Bs3 function is not restricted to the plant kingdom. The Bs3 sequence shows striking similarity to flavin monooxygenases (FMOs), an FAD- and NADPH-containing enzyme class that is known for the oxygenation of a wide range of substrates and their potential to produce H2O2. Since H2O2 is a hallmark metabolite in plant immunity, we analyzed the role of H2O2 during Bs3 HR. We purified recombinant Bs3 protein from E. coli and confirmed the FMO function of Bs3 with FAD binding and NADPH oxidase activity in vitro. Translational fusion of Bs3 to the redox reporter roGFP2 indicated that the Bs3-dependent HR induces an increase of the intracellular oxidation state in planta. To test if the NADPH oxidation and putative H2O2 production of Bs3 is sufficient to induce HR, we adapted previous studies which have uncovered mutations in the NADPH binding site of FMOs that result in higher NADPH oxidase activity. In vitro studies demonstrated that recombinant Bs3S211A protein has twofold higher NADPH oxidase activity than wildtype Bs3. Translational fusions to roGFP2 showed that Bs3S211A also increased the intracellular oxidation state in planta. Interestingly, while the mutant derivative Bs3S211A had an increase in NADPH oxidase capacity, it did not trigger HR in planta, ultimately revealing that H2O2 produced by Bs3 on its own is not sufficient to trigger HR.
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Affiliation(s)
- Christina Krönauer
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - Thomas Lahaye
- University of Tübingen, ZMBP–General Genetics, Tuebingen, Germany
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Krönauer C, Radutoiu S. Understanding Nod factor signalling paves the way for targeted engineering in legumes and non-legumes. Curr Opin Plant Biol 2021; 62:102026. [PMID: 33684882 DOI: 10.1016/j.pbi.2021.102026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/31/2021] [Accepted: 02/05/2021] [Indexed: 05/06/2023]
Abstract
Legumes evolved LysM receptors for recognition of rhizobial Nod factors and initiation of signalling pathways for nodule organogenesis and infection. Intracellularly hosted bacteria are supplied with carbon resources in exchange for fixed nitrogen. Nod factor recognition is crucial for initial signalling, but is reiterated in growing roots initiating novel symbiotic events, and in developing primordia until symbiosis is well-established. Understanding how this signalling coordinates the entire process from cellular to plant level is key for de novo engineering in non-legumes and for improved efficiency in legumes. Here we discuss how recent studies bring new insights into molecular determinants of specificity and sensitivity in Nod factor signalling in legumes, and present some of the unknowns and challenges for engineering.
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Affiliation(s)
- Christina Krönauer
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds vej 10, 8000C, Aarhus, Denmark
| | - Simona Radutoiu
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds vej 10, 8000C, Aarhus, Denmark.
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Bozsoki Z, Gysel K, Hansen SB, Lironi D, Krönauer C, Feng F, de Jong N, Vinther M, Kamble M, Thygesen MB, Engholm E, Kofoed C, Fort S, Sullivan JT, Ronson CW, Jensen KJ, Blaise M, Oldroyd G, Stougaard J, Andersen KR, Radutoiu S. Ligand-recognizing motifs in plant LysM
receptors are major determinants of
specificity. Science 2020; 369:663-670. [DOI: 10.1126/science.abb3377] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 06/12/2020] [Indexed: 01/02/2023]
Abstract
Plants evolved lysine motif (LysM)
receptors to recognize and parse microbial
elicitors and drive intracellular signaling to
limit or facilitate microbial colonization. We
investigated how chitin and nodulation (Nod)
factor receptors of Lotus
japonicus initiate differential
signaling of immunity or root nodule symbiosis.
Two motifs in the LysM1 domains of these receptors
determine specific recognition of ligands and
discriminate between their in planta functions.
These motifs define the ligand-binding site and
make up the most structurally divergent regions in
cognate Nod factor receptors. An adjacent motif
modulates the specificity for Nod factor
recognition and determines the selection of
compatible rhizobial symbionts in legumes. We also
identified how binding specificities in LysM
receptors can be altered to facilitate Nod factor
recognition and signaling from a chitin receptor,
advancing the prospects of engineering rhizobial
symbiosis into nonlegumes.
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Affiliation(s)
- Zoltan Bozsoki
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Kira Gysel
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Simon B. Hansen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Damiano Lironi
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Christina Krönauer
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Feng Feng
- Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, UK
| | - Noor de Jong
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Maria Vinther
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Manoj Kamble
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Mikkel B. Thygesen
- Department of Chemistry, University of Copenhagen, 1871 Frederiksberg, Denmark
| | - Ebbe Engholm
- Department of Chemistry, University of Copenhagen, 1871 Frederiksberg, Denmark
| | - Christian Kofoed
- Department of Chemistry, University of Copenhagen, 1871 Frederiksberg, Denmark
| | - Sébastien Fort
- Université Grenoble Alpes, CNRS, CERMAV, 38000 Grenoble, France
| | - John T. Sullivan
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Clive W. Ronson
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Knud J. Jensen
- Department of Chemistry, University of Copenhagen, 1871 Frederiksberg, Denmark
| | - Mickaël Blaise
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Giles Oldroyd
- Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, UK
| | - Jens Stougaard
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Kasper R. Andersen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Simona Radutoiu
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
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Krönauer C, Kilian J, Strauß T, Stahl M, Lahaye T. Cell Death Triggered by the YUCCA-like Bs3 Protein Coincides with Accumulation of Salicylic Acid and Pipecolic Acid But Not of Indole-3-Acetic Acid. Plant Physiol 2019; 180:1647-1659. [PMID: 31068387 PMCID: PMC6752908 DOI: 10.1104/pp.18.01576] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/29/2019] [Indexed: 06/09/2023]
Abstract
The pepper (Capsicum annuum) resistance gene bacterial spot3 (Bs3) is transcriptionally activated by the matching Xanthomonas euvesicatoria transcription-activator-like effector (TALE) AvrBs3. AvrBs3-induced Bs3 expression triggers a rapid and local cell death reaction, the hypersensitive response (HR). Bs3 is most closely related to plant flavin monooxygenases of the YUCCA (YUC) family, which catalyze the final step in auxin biosynthesis. Targeted mutagenesis of predicted NADPH- and FAD-cofactor sites resulted in Bs3 derivatives that no longer trigger HR, thereby suggesting that the enzymatic activity of Bs3 is crucial to Bs3-triggered HR. Domain swap experiments between pepper Bs3 and Arabidopsis (Arabidopsis thaliana) YUC8 uncovered functionally exchangeable and functionally distinct regions in both proteins, which is in agreement with a model whereby Bs3 evolved from an ancestral YUC gene. Mass spectrometric measurements revealed that expression of YUCs, but not expression of Bs3, coincides with an increase in auxin levels, suggesting that Bs3 and YUCs, despite their sequence similarity, catalyze distinct enzymatic reactions. Finally, we found that expression of Bs3 coincides with increased levels of the salicylic acid and pipecolic acid, two compounds that are involved in systemic acquired resistance.
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Affiliation(s)
- Christina Krönauer
- Center for Plant Molecular Biology, Eberhard-Karls-University Tuebingen, Tuebingen 72076, Germany
| | - Joachim Kilian
- Center for Plant Molecular Biology, Eberhard-Karls-University Tuebingen, Tuebingen 72076, Germany
| | - Tina Strauß
- Integrated Plant Genetics, Inc., Gainesville, Florida 32653
- Genetics, Faculty of Biology, Ludwig-Maximilians-University, D-82152 Munich Martinsried, Germany
| | - Mark Stahl
- Center for Plant Molecular Biology, Eberhard-Karls-University Tuebingen, Tuebingen 72076, Germany
| | - Thomas Lahaye
- Center for Plant Molecular Biology, Eberhard-Karls-University Tuebingen, Tuebingen 72076, Germany
- Genetics, Faculty of Biology, Ludwig-Maximilians-University, D-82152 Munich Martinsried, Germany
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Shantharaj D, Römer P, Figueiredo JFL, Minsavage GV, Krönauer C, Stall RE, Moore GA, Fisher LC, Hu Y, Horvath DM, Lahaye T, Jones JB. An engineered promoter driving expression of a microbial avirulence gene confers recognition of TAL effectors and reduces growth of diverse Xanthomonas strains in citrus. Mol Plant Pathol 2017; 18:976-989. [PMID: 27362693 PMCID: PMC6638256 DOI: 10.1111/mpp.12454] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [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: 01/19/2016] [Revised: 04/13/2016] [Accepted: 06/27/2016] [Indexed: 05/19/2023]
Abstract
Xanthomonas citri ssp. citri (X. citri), causal agent of citrus canker, uses transcription activator-like effectors (TALEs) as major pathogenicity factors. TALEs, which are delivered into plant cells through the type III secretion system (T3SS), interact with effector binding elements (EBEs) in host genomes to activate the expression of downstream susceptibility genes to promote disease. Predictably, TALEs bind EBEs in host promoters via known combinations of TALE amino acids to DNA bases, known as the TALE code. We introduced 14 EBEs, matching distinct X. citri TALEs, into the promoter of the pepper Bs3 gene (ProBs31EBE ), and fused this engineered promoter with multiple EBEs (ProBs314EBE ) to either the β-glucuronidase (GUS) reporter gene or the coding sequence (cds) of the pepper gene, Bs3. TALE-induced expression of the Bs3 cds in citrus leaves resulted in no visible hypersensitive response (HR). Therefore, we utilized a different approach in which ProBs31EBE and ProBs314EBE were fused to the Xanthomonas gene, avrGf1, which encodes a bacterial effector that elicits an HR in grapefruit and sweet orange. We demonstrated, in transient assays, that activation of ProBs314EBE by X. citri TALEs is T3SS dependent, and that the expression of AvrGf1 triggers HR and correlates with reduced bacterial growth. We further demonstrated that all tested virulent X. citri strains from diverse geographical locations activate ProBs314EBE . TALEs are essential for the virulence of X. citri strains and, because the engineered promoter traps are activated by multiple TALEs, this concept has the potential to confer broad-spectrum, durable resistance to citrus canker in stably transformed plants.
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Affiliation(s)
- Deepak Shantharaj
- Plant Pathology DepartmentUniversity of FloridaGainesvilleFL 32611USA
| | - Patrick Römer
- Genetics, Department of Biology, Ludwig‐Maximilians‐University MunichMartinsriedD‐82152Germany
- Present address:
Nomad Bioscience GmbH, Biozentrum Halle Weinbergweg 22 D‐06120 Halle (Saale)
| | | | | | - Christina Krönauer
- Zentrum für Molekularbiologie der Pflanzen (ZMBP)Eberhard‐Karls‐Universität TübingenAuf der Morgenstelle 32TübingenD‐72076Germany
| | - Robert E. Stall
- Plant Pathology DepartmentUniversity of FloridaGainesvilleFL 32611USA
| | - Gloria A. Moore
- Department of Horticultural SciencesUniversity of FloridaGainesvilleFL 32611USA
| | - Latanya C. Fisher
- Department of Horticultural SciencesUniversity of FloridaGainesvilleFL 32611USA
| | - Yang Hu
- Plant Pathology DepartmentUniversity of FloridaGainesvilleFL 32611USA
| | - Diana M. Horvath
- 2Blades Foundation, Suite 19011630 Chicago AvenueEvanstonIL60201USA
| | - Thomas Lahaye
- Genetics, Department of Biology, Ludwig‐Maximilians‐University MunichMartinsriedD‐82152Germany
- Zentrum für Molekularbiologie der Pflanzen (ZMBP)Eberhard‐Karls‐Universität TübingenAuf der Morgenstelle 32TübingenD‐72076Germany
| | - Jeffrey B. Jones
- Plant Pathology DepartmentUniversity of FloridaGainesvilleFL 32611USA
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Abstract
The objective of this study was to determine the transonychial water loss (TOWL) in both healthy and affected nails in different diseases and to compare it with the transepidermal water loss (TEWL). TOWL was measured by a new evaporimetric method: Plasticine was used to fix the protection cover of the evaporimeter probe to the nails. The TOWL behaved contrary to the TEWL. Affected nails in patients with atopic eczema (p <0.01), psoriasis (p<0.05) and onychomycosis (p<0.001) showed a significantly lower TOWL than did nails of healthy test subjects. The decrease in TOWL in diseased nails in comparison to healthy nails could be due to the formation of a stratum granulosum in atopic, psoriatic or fungus-affected nails, as this layer is normally absent in healthy nails.
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Affiliation(s)
- C Krönauer
- Department of Dermatology and Allergy, Biederstein, Technical University Munich, Germany.
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Krönauer C, Eberlein-König B, Ring J, Behrendt H. Inhibition of histamine release of human basophils and mast cells in vitro by ultraviolet A (UVA) irradiation. Inflamm Res 2001; 50 Suppl 2:S44-6. [PMID: 11411597 DOI: 10.1007/pl00022401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
- C Krönauer
- Department of Dermatology and Allergology, Biederstein, Technical University Munich, Germany.
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