SBP transcriptional regulator probably involved in the domestication of maize. Acts as a transcriptional repressor binding to a 5'-GTAC-3' motif. May repress the growth of lateral branches in length and numbers. Monomer and homodimer. Strongly expressed in immature ears and weakly in husks. Found in the inflorescence meristem of the developing ear, in the spikelet pair primordia, the glume primordia, the cupule forming region and other floral organs. Not detected in other tissues. The N-terminal domain is necessary for dimerization. A single Lys to Asn substitution at position 6 is the probable cause of the transition from the hardened fruitcase surrounding the kernels in teosinte to the cob that bears naked grains in maize. This substitution is not affecting the DNA binding site specificity, but increases the stability of the homodimers.