Genome-Wide Identification of the SQUAMOSA Promoter-Binding Protein-like (SPL) Transcription Factor Family in Sweet Cherry Fruit.

Plant-specific SQUAMOSA promoter-binding protein-like (SPL) transcription factors play important regulatory roles during plant growth and development, fruit ripening, inflorescence branching, and biotic and abiotic stresses. However, there have been no identification or systematic studies of the SPL gene family in the sweet cherry. In this study, 12 genes were identified in the sweet cherry reference genome, which were distributed over 6 chromosomes and classified into six groups according to phylogenetic relationships with other SPL gene families. Nine were highly expressed at green fruit stages and dramatically decreased at the onset of fruit ripening, which implied that they were important regulators during fruit development and ripening. The expression patterns of genes under ABA, GA, and MeJA treatments showed that the were involved in the process of fruit ripening. A subcellular localization experiment proved that PavSPL4 and PavSPL7 proteins were localized in the nucleus. The genome-wide identification of the gene family provided new insights while establishing an important foundation for sweet cherry studies.