2-oxoglutarate-dependent dioxygenase involved in the oxidation of jasmonate (JA), a stress-induced phytohormone synthesized in response to attack by pathogens and herbivores, which triggers the activation of defense responses via the JA-mediated signaling pathway (PubMed:28559313). Converts JA to 12-hydroxyjasmonate (12OH-JA), an inactive form of JA (PubMed:28559313). Prevents over-accumulation of JA and indirectly its bioactive form JA-Ile under stress response (PubMed:28559313). Acts as negative regulator of JA-mediated defense signaling, by contributing to 12OH-JA accumulation, which represses JA defense responses upon infection by the fungal pathogen Botrytis cinerea and the herbivorous caterpillar Mamestra brassicae (PubMed:28559313). 2-oxoglutarate + jasmonate + O2 = (1R,2R)-12-hydroxyjasmonate + CO2 + succinate Binds 1 Fe(2+) ion per subunit. A number of isoforms are produced. According to EST sequences. Expressed during pollen germination and pollen tube growth. Induced at low levels by wounding (PubMed:28760569). Induced by methyl jasmonate (MeJA), infection by the fungal pathogen Botrytis cinerea and infestation with the caterpillar Mamestra brassicae (PubMed:28559313). The quadruple mutant jox1, jox2, jox3 and jox4 exhibit reduced root and shoot growth, delayed flowering, reduced seed production, constitutively elevated jasmonate and jasmonoyl-L-isoleucine levels, and enhanced resistance to the necrotrophic fungal pathogen Botrytis cinerea and the herbivorous caterpillar Mamestra brassicae. Belongs to the iron/ascorbate-dependent oxidoreductase family.