Involved in the control of epidermal cell morphogenesis in petals. Promotes unidirectional cell expansion once outgrowth has been initiated (PubMed:17376813). Coordinately with WIN1/SHN1, participates in the regulation of cuticle biosynthesis and wax accumulation in reproductive organs and trichomes. Functions in cuticle nanoridge formation in petals and stamens, and in morphogenesis of petal conical cells and trichomes (PubMed:23709630). Functions as a major regulator of cuticle formation in vegetative organs by regulating the cuticle biosynthesis genes CYP86A8/LCR and CER1 (PubMed:24169067). Expressed in trichomes, epidermis and mesophyll cells of young leaves, stems, petals, sepals, carpels and stamens.