Transcription factor that functions as regulator of genes affecting cell wall organization and remodeling. Activates genes related to the primary cell wall and represses genes related to the secondary cell wall and expansins. Required for the regulation of longitudinal cell growth in stems, leaves, petioles, roots, flowers and siliques. Expressed in roots, leaves, internodes, shoot tips and flowers. Extended C-terminus. Truncated N-terminus. Truncated N-terminus.