AP2/ERF Transcription Factors Integrate Age and Wound Signals for Root Regeneration

Age and wound are two major determinants for regeneration. In plants, the root regeneration is triggered by wound-induced auxin biosynthesis. As plants age, the root regenerative capacity is gradually decreased. How wound leads to the auxin burst and how age and wound signals collaboratively regulate root regenerative capacity are poorly understood. Here, we show that the increased level of three closely-related miR156-targeted SPL transcription factors, SPL2, SPL10 and SPL11, with age suppresses root regeneration by inhibiting wound-induced auxin biosynthesis. Mechanistically, we find that a subset of AP2/ERF transcription factors including ABR1 and ERF109 is rapidly induced by wound and serves as a proxy for wound signal to induce auxin biosynthesis. In older plants, SPL2/10/11 directly binds to the promoters of AP2/ERFs and attenuates their induction, thereby dampening auxin accumulation at the wound. Our results thus identify AP2/ERFs as a hub for integration of age and wound signal for root regeneration.