Probable transcription factor required for the flowering response to vernalization in the shoot apical meristem (SAM) (PubMed:30679374). Defines the competence of shoot meristems to flower in response to vernalization in perennials (PubMed:30679374). Induced in the shoot apical meristem (SAM) during vernalization. The SBP-type zinc finger is required for the binding to DNA. Spl15 mutant plants fail to flower after vernalization.