Inhibition of jasmonic acid‐isoleucine conjugating enzyme JAR1 shifts the local and systemic leaf signals and metabolic profiles in Arabidopsis

Jasmonates (JAs)-mediated pathways are central signaling hubs in plant defense responses. However, the identification of mobile and nonmobile signals involved in downstream systemic signaling is still less studied. Here, we investigate the role of the jasmonic acid-isoleucine (JA-Ile) conjugating enzyme, JAR1, in shifting wound-induced local and systemic metabolic profiles using liquid chromatography mass spectrometry (LC-MS/MS) for untargeted metabolomics, and the mobility of JA-Ile in wound-induced local and systemic defense using LC-MS/MS for targeted JAs analysis in Arabidopsis thaliana leaves. The use of jarin-1, a specific inhibitor of JA-Ile biosynthesis, suggested that JA-Ile was synthesized de novo in the particular tissues, rather than being a mobile signal. In addition, inhibition of JAR1 enzyme activity affected an array of downstream metabolic pathways, locally and systemically, such as amino acids and carbohydrate metabolism. This study suggests that the occurrence and spread of local and systemic downstream signals very likely depend on JAR1 activity, and this enzyme exclusively regulates a series of metabolic pathways under both wounding and nonwounding conditions.