Jasmonate-mediated wound signalling promotes plant regeneration

Wounding is the first event triggering regeneration 1 – 4 . However, the molecular basis of wound signalling pathways in plant regeneration is largely unclear. We previously established a method to study de novo root regeneration (DNRR) in Arabidopsis thaliana 5 , 6 , which provides a platform for analysing wounding. During DNRR, auxin is biosynthesized after leaf detachment and promotes cell fate transition to form the root primordium 5 – 7 . Here, we show that jasmonates (JAs) serve as a wound signal during DNRR. Within 2 h of leaf detachment, JA is produced in leaf explants and activates ETHYLENE RESPONSE FACTOR109 ( ERF109 ). ERF109 upregulates ANTHRANILATE SYNTHASE α1 ( ASA1 )—a tryptophan biosynthesis gene in the auxin production pathway 8 – 10 —dependent on the pre-deposition of SET DOMAIN GROUP8 ( SDG8 )-mediated histone H3 lysine 36 trimethylation (H3K36me3) 11 on the ASA1 locus. After 2 h, ERF109 activity is inhibited by direct interaction with JASMONATE-ZIM-DOMAIN (JAZ) proteins to prevent hypersensitivity to wounding. Our results suggest that a dynamic JA wave cooperates with histone methylation to upregulate a pulse of auxin production and promote DNRR in response to wounding. Using de novo root regeneration from a detached Arabidopsis leaf as a model system, the authors show that jasmonates are a crucial signalling step from wounding to a local auxin response.