WUSCHEL modulates Jasmonate signaling to control the balance between growth and defense in the shoot apical meristem

Here, we show that wounding of rosette leaves systemically inhibits inflorescence stem growth, associated with reduced cell proliferation in the inner cell layers of the shoot apical meristem (SAM), but not in the stem cell domain. Mechanistically, this selective cell behavior upon systemic wounding is dependent on the interplay between Jasmonate (JA) signaling, which represses growth, and the stem cell regulator WUSCHEL (WUS), which promotes growth.

WUS mitigates wounding-induced growth inhibition by repressing JA-responsive gene expression via promoting accumulation of JASMONATE-ZIM DOMAIN 3 (JAZ3), which encodes a JA signaling repressor. WUS on the one hand induces JAZ3 gene expression and on the other hand directly competes with the JA receptor COI1 for JAZ3 binding, inhibiting JAZ3 protein degradation. Our findings identify a WUS–JAZ3–COI1 regulatory module that coordinates the growth-defense balance in the SAM upon systemic wounding, revealing a cell type specific mechanism for sustaining developmental robustness of the meristem during stress responses.