Transcription factor that is specifically required for the development of root hairs (PubMed:17556585). Acts with RHD6 to positively regulate root hair development (PubMed:17556585). Acts downstream of genes that regulate epidermal pattern formation, such as GL2 (PubMed:17556585). Acts with RHD6 as transcription factor that integrates a jasmonate (JA) signaling pathway that stimulates root hair growth (PubMed:31988260). Homodimer (Probable). Forms heterodimers with RHD6 (PubMed:31988260). Interacts with TIFY10B/JAZ2, TIFY6A/JAZ4, TIFY5A/JAZ8, TIFY7/JAZ9 and TIFY9/JAZ10 (PubMed:31988260). Induced by jasmonate (JA) treatment. No visible phenotype under normal growht conditions, but the double mutant seedlings rhd6-3 and rsl1-1 do not develop root hairs.