Probable transcription factor (By similarity). Involved in spikelet transition. Regulator of starch biosynthesis especially during seed development (e.g. endosperm starch granules); represses the expression of type I starch synthesis genes. Prevents lemma and palea elongation as well as grain growth (By similarity). May form homodimer (By similarity). Interacts with TPR2/ASP1 (By similarity). Belongs to the AP2/ERF transcription factor family. AP2 subfamily.