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The chemical compound ‘Heatin’ stimulates hypocotyl elongation and interferes with the Arabidopsis NIT1-subfamily of nitrilases |
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| Authors: | Lennard van der Woude Markus Piotrowski Gruson Klaasse Judith K Paulus Daniel Krahn Sabrina Ninck Farnusch Kaschani Markus Kaiser Ond?ej Novák Karin Ljung Suzanne Bulder Marcel van Verk Basten L Snoek Martijn Fiers Nathaniel I Martin Renier A L van der Hoorn Stéphanie Robert Sjef Smeekens Martijn van Zanten |
| Institution: | 1. Molecular Plant Physiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, Utrecht, 3584 CH the Netherlands;2. Department of Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Universitätsstraße 150, Bochum, 44801 Germany;3. Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, University Utrecht, Universiteitsweg 99, Utrecht, 3584 CG the Netherlands;4. Plant Chemetics Laboratory, Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB UK;5. Chemische Biologie, Zentrum für Medizinische Biotechnologie, Fakultät für Biologie, Universität Duisburg-Essen, Universitätsstr. 2, Essen, 45117 Germany;6. Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umea, SE-901 83 Sweden
Laboratory of Growth Regulators, The Czech Academy of Sciences & Faculty of Science, Institute of Experimental Botany, Palacký University, ?lechtitel? 27, Olomouc, 78371 Czech Republic;7. Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umea, SE-901 83 Sweden;8. Bejo Zaden B.V., Trambaan 1, Warmenhuizen, 1749 CZ the Netherlands;9. Plant-Microbe Interactions, Institute of Environmental Biology, Utrecht University, Padualaan 8, Utrecht, 3584 CH the Netherlands Keygene, Agro Business Park 90, Wageningen, 6708 PW the Netherlands Theoretical Biology and Bioinformatics, Institute of Biodynamics and Biocomplexity, Utrecht University, Padualaan 8, Utrecht, 3584 CH the Netherlands;10. Theoretical Biology and Bioinformatics, Institute of Biodynamics and Biocomplexity, Utrecht University, Padualaan 8, Utrecht, 3584 CH the Netherlands;11. Bioscience, Wageningen University and Research, Droevendaalsesteeg 1, Wageningen, 6708 PB the Netherlands;12. Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, University Utrecht, Universiteitsweg 99, Utrecht, 3584 CG the Netherlands Biological Chemistry Group, Sylvius Laboratories, Institute of Biology Leiden, Leiden University, Sylviusweg 72, Leiden, 2333 BE the Netherlands |
| Abstract: | Temperature passively affects biological processes involved in plant growth. Therefore, it is challenging to study the dedicated temperature signalling pathways that orchestrate thermomorphogenesis, a suite of elongation growth-based adaptations that enhance leaf-cooling capacity. We screened a chemical library for compounds that restored hypocotyl elongation in the pif4-2–deficient mutant background at warm temperature conditions in Arabidopsis thaliana to identify modulators of thermomorphogenesis. The small aromatic compound ‘Heatin’, containing 1-iminomethyl-2-naphthol as a pharmacophore, was selected as an enhancer of elongation growth. We show that ARABIDOPSIS ALDEHYDE OXIDASES redundantly contribute to Heatin-mediated hypocotyl elongation. Following a chemical proteomics approach, the members of the NITRILASE1-subfamily of auxin biosynthesis enzymes were identified among the molecular targets of Heatin. Our data reveal that nitrilases are involved in promotion of hypocotyl elongation in response to high temperature and Heatin-mediated hypocotyl elongation requires the NITRILASE1-subfamily members, NIT1 and NIT2. Heatin inhibits NIT1-subfamily enzymatic activity in vitro and the application of Heatin accordingly results in the accumulation of NIT1-subfamily substrate indole-3-acetonitrile in vivo. However, levels of the NIT1-subfamily product, bioactive auxin (indole-3-acetic acid), were also significantly increased. It is likely that the stimulation of hypocotyl elongation by Heatin might be independent of its observed interaction with NITRILASE1-subfamily members. However, nitrilases may contribute to the Heatin response by stimulating indole-3-acetic acid biosynthesis in an indirect way. Heatin and its functional analogues present novel chemical entities for studying auxin biology. |
| Keywords: | chemical genetics thermomorphogenesis Arabidopsis nitrilases NIT1-subfamily Heatin aldehyde oxidase PIF4 1-iminomethyl-2-naphthol IAN indole-3-acetonitrile |