May contribute to cell wall structure in root hairs. Exclusively expressed in roots, particularly in root hairs-containing regions, and especially in root hairs. After germination, present in root epidermis and root hairs localized around the transition zone marking the root/shoot junction. Later expressed in root epidermis and root hairs, mostly in the root zone forming new hairs. Absent from the root tip. In adult plants restricted to root hair development regions of the main root and lateral roots. By 1-aminocyclo-propane-1-carboxylic acid (ACC) and a-naphthaleneacetic acid (alpha-NAA), ethylene and auxin precursors. Repressed by the ethylene inhibitor 1-a-(2-aminoethoxyvinyl)glycine (AVG). Lower levels in calcium-depleted conditions. Belongs to the plant proline-rich protein superfamily. ENOD12 family.