Figure 1.

Coordination between the endoreplication programme and cell growth during trichome development. Trichome development starts with cell fate specification of some protodermal cells in the epidermis by expression of the homeobox gene GL2. These cells arrest cell division and switch to the endoreplication programme, which is modulated by various regulatory pathways and associated to the branching stage, genetically controlled by different genes. Late during trichome development, GTL1 accumulates leading to termination of the endocycle programme and to arrest of the endoreplication-independent trichome growth. Note that some of the endocycle control pathways have not been specifically demonstrated to operate in trichomes. Red and green fonts indicate activators and repressors of the pathway, respectively.