Inhibition of Jasmonic Acid-Isoleucine Conjugating Enzyme JAR1 Shifts the Local and Systemic Leaf Metabolic Profiles in <em>Arabidopsis</em>

• Jasmonates (JAs)-mediated pathways are central signaling hubs in plant defense response. However, the identification of mobile and non-mobile signals involved in downstream systemic signaling is still less studied. • Here, we investigate the role of the jasmonic acid-isoleucine conjugating enzyme, JAR1, and the mobility of jasmonic acid-isoleucine (JA-Ile) in wound-induced local and systemic defense using LC-MS/MS for targeted jasmonate analysis and untargeted metabolomics in Arabidopsis thaliana leaves. • The use of jarin-1, a specific inhibitor of JA-Ile biosynthesis, suggested that JA-Ile is 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 demonstrates that the occurrence and spread of local and systemic downstream signals depend on JAR1 activity, and this enzyme exclusively regulates a series of metabolic pathways under both wounding and non-wounding conditions.