Acts as positive regulator of adventitious (crown) root formation by promoting its initiation. Promotes adventitious root initiation through repression of cytokinin signaling by positively regulating the two-component response regulator RR1. Regulated by the auxin response factor and transcriptional activator ARF23/ARF1. Highly expressed at the base of the stem. Expressed in stems. Expressed a low levels in crown roots and seeds (PubMed:21807632). Expressed in the stem region where adventitious (crown) root initiation occurs (PubMed:21481033). Induced by auxin. Strong reduction of adventitious (crown) root formation. Belongs to the AP2/ERF transcription factor family. AP2 subfamily.