ABA inhibits in vitro shoot regeneration by affecting H3K9ac modification of WUS in Arabidopsis.

The phytohormone abscisic acid (ABA) is an important regulator of plant growth, but its potential participation in the process of in vitro shoot regeneration has not to date been reported. Here, we found that ABA appeared to inhibit in vitro shoot regeneration. ABA represses the formation of stem cell niches, thereby reducing the shoot regeneration by localizing the expression of WUSCHEL (WUS). During in vitro shoot regeneration, enrichment of H3K9ac in the specific region of WUS is a necessary event for its activation which could be inhibited by exogenous ABA. These findings reveal the potential function, as well as the possible way of ABA in regulating de novo shoot regeneration in Arabidopsis.