The loss-of-function GLABROUS 3 mutation in cucumber is due to LTR-retrotransposon insertion in a class IV HD-ZIP transcription factor gene CsGL3 that is epistatic over CsGL1

Trichomes, developed from the protodermal cells (the outermost cell layer of the embryo), are hairlike structures covering the aerial parts of plants. The genetic network regulating trichome development has been extensively studied and well understood in the model species Arabidopsis thaliana, which bears unicellular, nonglandular and branched trichomes.