MYB-type transcription factor involved in trichome cell specification. Acts as a negative regulator of trichome patterning and formation by direct binding to the cis-acting regulatory elements of GL1, thus suppressing the expression of GL1. Expressed in inflorescences and trichomes of rosette and cauline leaves. Trichome formation on inflorescence stems and pedicels. Plants over-expressing TCL1 does not have any trichomes on rosette leaves, inflorescence stems, cauline leaves or floral organs.