The JA-to-ABA signaling relay promotes lignin deposition for wound healing in Arabidopsis

Plants are frequently exposed to herbivory and mechanical damage that result in wounding. Two fundamental strategies, regeneration and healing, are employed by plants upon wounding. How plants make different decisions and how wound healing is sustained until the damaged tissues recover are not fully understood. In this study, we found that local auxin accumulation patterns, determined by wounding modes, may activate different recovery programs in wounded tissues. Wounding triggers transient jasmonic acid (JA) signaling that promotes lignin deposition in the first few hours after wounding occurs. This early response is subsequently relayed to ABA signaling via MYC2. The induced JA signaling promotes ABA biosynthesis to maintain the expression of RAP2.6, a key factor for sustained lignin biosynthesis and the later wound-healing process. Our findings provide mechanistic insights into how plants heal from wounding and clarify the molecular mechanisms that underlie the prolonged healing process following wounding. A regulatory module comprising MYCs and RAP2.6 plays a central role in upregulating lignin biosynthesis genes in response to plant wounding. Sustained lignin accumulation at the wound site is underpinned by the transition from JA signaling to ABA signaling, which maintains the persistent expression of RAP2.6. Our findings clarify the hormonal interplay that governs the healing process after plant wounding.