How do plants transduce wound signals to induce tissue repair and organ regeneration?

Wounding is a primary trigger for tissue repair and organ regeneration, yet the exact regulatory role of local wound signals remained elusive for many years. Recent studies demonstrated that a key signaling molecule of wound response, jasmonic acid (JA), plays pivotal roles in root regeneration. JA signaling induces cell proliferation and restores root meristem by ectopically inducing an AP2/ERF transcription factor ETHYLENE RESPONSE FACTOR 115 (ERF115) which in normal development, replenishes quiescent center cells. During shoot regeneration, another wound inducible AP2/ERF transcription factor WOUND INDUCED DEDIFFERENTIATION 1 (WIND1) promotes callus formation and shoot regeneration via direct induction of a shoot meristem regulator. Discovery of these regulatory mechanisms highlights the direct link between stress signaling and ectopic activation of developmental programs. Given that genes encoding key developmental regulators are often under epigenetic regulation, transcriptional activation of these genes likely entails changes in their chromatin status. Recent efforts indeed began to reveal massive changes in histone modification status during cellular reprogramming after wounding.