The 11-hydroxy-jasmonic acid pathway expands jasmonate catabolic repertoire for stress-specific hormone attenuation in Arabidopsis

Several jasmonates result from catabolism of the master regulator jasmonoyl-isoleucine (JA-Ile) that controls most jasmonate responses upon developmental or environmental cues. Hydroxylation of the precursor jasmonic acid by Jasmonic Acid Oxidases (JAO) holds a peculiar regulatory function, by attenuating basal JA-Ile formation and action, and promoting growth.

Here we re-investigated the nature and origins of hydroxy-JAs and their derivatives in Arabidopsis. Using advanced analytical methods and pathway-impaired mutants, we show that JAO enzymes produce exclusively 11OH-JA and are preferentially recruited in response to fungal infection where 11-O-Glc-JA accumulates as its main glucosylated derivative. Conversly, mechanical wounding triggers the dominant formation of 12-OH-JA (and its derivatives 12-O-Glc-JA and 12-HSO4-JA) as a cleavage product of the JA-Ile catabolite 12OH-JA-Ile by amidohydrolase activity.