Required for exine pattern formation during pollen development, especially for primexine deposition. Mostly expressed in buds, and, to a lower extent, in leaves, roots and seedlings. Male sterile. Defective pollen wall pattern formation at early tetrad stage; delayed and reduced primexine deposition, as well as abnormal rippling of the plasma membrane and no production of spacers. Random sporopollenin deposition on the plasma membrane along the microspore wall.