Age and wounding 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 gradually decreases. How wounding 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 levels of three closely-related miR156-targeted Arabidopsis (Arabidopsis thaliana) SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) transcription factors, SPL2, SPL10, and SPL11, suppress root regeneration with age by inhibiting wound-induced auxin biosynthesis. Mechanistically, we find that a subset of APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) transcription factors including ABSCISIC ACID REPRESSOR1 and ERF109 is rapidly induced by wounding and serves as a proxy for wound signal to induce auxin biosynthesis. In older plants, SPL2/10/11 directly bind 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.

NAC (NAM/ATAF/CUC) transcription factors comprise a large plant-specific gene family that contains more than 149 members in rice. Extensive studies have revealed that NAC transcription factors not only play important roles in plant growth and development, but also have functions in regulation of responses to biotic and abiotic stresses. However, biological functions for most of the members in the NAC family remain unknown. In this study, microarray data analyses revealed that a total of 63 ONAC genes exhibited overlapping expression patterns in rice under various abiotic (salt, drought, and cold) and biotic (infection by fungal, bacterial, viral pathogens, and parasitic plants) stresses. Thirty-eight ONAC genes exhibited overlapping expression in response to any two abiotic stresses, among which 16 of 30 selected ONAC genes were upregulated in response to exogenous ABA. Sixty-five ONAC genes showed overlapping expression patterns in response to any two biotic stresses. Results from the present study suggested that members of the ONAC genes with overlapping expression pattern may have pleiotropic biological functions in regulation of defense response against different abiotic and biotic stresses, which provide clues for further functional analysis of the ONAC genes in stress tolerance and pathogen resistance.