Epidermal cell-patterning genes of the stem parasitic plant are involved in the development of holdfasts.

, a stem parasitic plant, commences its parasitic behavior by forming a specialized disk-like adhesive structure called a holdfast, which facilitates tight adhesion to the stem surface of the host plant. The morphology of epidermal cells in the holdfast is similar to that of the leaf trichome and root hairs of dicotyledonous plants. However, the regulatory network underlying the development of the holdfast has not been elucidated to date. In this study, we assessed the roles of epidermal cell-patterning genes in the development of a holdfast. Epidermal cell-patterning genes of , including , , , , and , were expressed slightly before the initiation of the outgrowth of stem epidermal cells. silencing repressed , , , , ; therefore, is an upstream regulator of other epidermal cell-patterning genes. Unlike other genes, was not upregulated after attachment to the host, and was not repressed by -silencing. Protein interaction assays demonstrated that CcJKD interacted with CcTTG1 and CcCPC. Furthermore, -silencing repressed the outgrowth of holdfast epidermal cells. Therefore, invokes epidermal cell-patterning genes for the outgrowth of holdfast epidermal cells, and their regulatory mechanism is different from those for leaf trichome or root hairs.