Schematic representation of the Pleiades’ mechanism of action

The pleiades gene cluster in the Ustilago maydis (corn smut) genome encodes a family of proteins, the Pleiades, that target maize immunity. The two Pleiades Taygeta1 (Tay1) and Merope1 (Mer1) inhibit Reactive Oxygen Species (ROS) production, albeit in different cell compartments. Additionally, Mer1 acts in the nucleus to modify the activity of RFI2 homologues (Red and Far-Red Insensitive 2), a family of enzymes involved in early immune responses and that govern flowering time in plants.