Cloning, Characterization, and Overexpression in Arabidopsis to Determine the Function of SPL Genes from Woodland Strawberry (Fragaria Vesca)

Abstract

SQUAMOSA promoter binding protein-like (SPL) proteins is a class of plant specific transcription factors that play important roles during plant development. However, the majority of SPL genes in strawberry are functionally uncharacterized. In this study, three SPL genes, i.e. FvSPL1, FvSPL2, and FvSPL11 (FvSPL1/2/11), from woodland strawberry were cloned and characterized. Phylogenetic analysis with SPL genes from Arabidopsis, tomato and chrysanthemum indicated that FvSPL1/2/11 were clustered into the same group with those of miR156 target site located at the 3’-untranslated region (UTR). Further biochemical analysis indicated that FvSPL1 was exclusively localized in the nucleus. Electrophoretic mobility shift assay demonstrated FvSPL1 could specifically recognized the GTAC motif. Transcriptional activity analysis showed FvSPL1 was a transcriptional activator that could activate the expression of FvAP1 gene. Finally, all of the transgenic Arabidopsis that overexpression the three FvSPL genes were exhibited significantly early flowering phenotype. Taken together, our study indicated that FvSPL1/2/11 similar to their orthologs in Arabidopsis mainly functions in regulating plant flowering. These results enriched our understanding to the functions of SPL genes in strawberry and might be utilized for strawberry flowering time manipulation in the future.