Transcriptional regulator involved in the specification of floral identity. Acts as A class cadastral protein by repressing the C class floral homeotic gene AGAMOUS in the external flower organs in association with APETALA2 and other repressors. Is required to maintain floral meristem identity in concert with AGAMOUS. Interacts also with APETALA2 to ensure the normal development of ovule. Expressed in inflorescence and floral meristems, young floral organ primordia, and later in ovule primordia. Mutations in the SAP gene result in the ectopic expression of AGAMOUS, leading to partial homeotic transformation of the external floral organs. Mutations affect equally ovule development and cause floral sterility.