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:28760569, PubMed:28559313). Converts JA to 12-hydroxyjasmonate (12OH-JA), an inactive form of JA (PubMed:28760569, PubMed:28559313). Is specific to free JA, and cannot oxidize the bioactive form jasmonoyl-L-isoleucine (JA-Ile) or other JA-amino acid conjugates (PubMed:28760569). Prevents over-accumulation of JA and indirectly its bioactive form JA-Ile under stress response (PubMed:28760569, 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 (PubMed:28760569, PubMed:28559313). Acts as negative regulator of JA-mediated defense responses upon infestation by the herbivorous caterpillar Mamestra brassicae (PubMed:28559313). 2-oxoglutarate + jasmonate + O2 = (1R,2R)-12-hydroxyjasmonate + CO2 + succinate Binds 1 Fe(2+) ion per subunit. Induced by methyl jasmonate (MeJA) (PubMed:20565618, PubMed:28559313). Induced by infection with the bacterial pathogen Pseudomonas syringae pv. maculicola (PubMed:20565618, PubMed:15098125). Induced by wounding (PubMed:17544464, PubMed:28760569). Induced by infection with the fungal pathogen Botrytis cinerea (PubMed:28760569, PubMed:28559313). Induced by 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.