Jasmonates are a family of oxylipin phytohormones regulating plant development and growth and mediating "defense versus growth" responses. The upstream JA biosynthetic precursor cis-(+)-12-oxo-phytodienoic acid (cis-OPDA) acts independently of CORONATIVE INSENSITIVE 1-mediated JA signaling in several stress-induced and developmental processes. However, its perception and metabolism are only partially understood. An isoleucine analog of the biologically active JA-Ile, OPDA-Ile, was detected years ago in wounded leaves of flowering plants, opening up the possibility that conjugation of cis-OPDA to amino acids might be a relevant mechanism for cis-OPDA regulation. Here, we extended the analysis of amino acid conjugates of cis-OPDA and identified naturally occurring OPDA-Val, OPDA-Phe, OPDA-Ala, OPDA-Glu, and OPDA-Asp accumulating in response to biotic and abiotic stress in Arabidopsis (Arabidopsis thaliana). The OPDA amino acid conjugates displayed cis-OPDA-related plant responses in a JA-Ile-dependent manner. We also showed that the synthesis and hydrolysis of cis-OPDA amino acid conjugates are mediated by members of the amidosynthetase GRETCHEN HAGEN 3 and the amidohydrolase INDOLE-3-ACETYL-LEUCINE RESISTANT 1/ILR1-like families. Thus, OPDA amino acid conjugates function in the catabolism or temporary storage of cis-OPDA in stress responses instead of acting as chemical signals per se.

Department of Chemical Biology Faculty of Science Palacký University Šlechtitelů 27 CZ 77900 Olomouc Czech Republic

Department of Development and Environmental Studies Faculty of Science Palacký University tř 17 listopadu 12 CZ 77146 Olomouc Czech Republic

Department of Experimental Biology Faculty of Science Palacký University Šlechtitelů 27 Olomouc CZ 77900 Czech Republic

Department of Molecular Signal Processing Leibniz Institute of Plant Biochemistry Weinberg 3 Halle D 06120 Germany

Graduate School of Science Tohoku University Aoba ku Sendai JP 980 8578 Japan

Laboratory of Functional Genomics and Proteomics National Centre for Biomolecular Research Faculty of Science and Plant Sciences Core Facility Mendel Centre for Plant Genomics and Proteomics CEITEC Masaryk University Kamenice 5 CZ 62500 Brno Czech Republic

Laboratory of Growth Regulators Faculty of Science Palacký University Šlechtitelů 27 Olomouc CZ 77900 Czech Republic

Laboratory of Growth Regulators Institute of Experimental Botany The Czech Academy of Sciences Šlechtitelů 27 Olomouc CZ 77900 Czech Republic

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