AaZFP3, a Novel CCCH-Type Zinc Finger Protein from Adonis amurensis , Promotes Early Flowering in Arabidopsis by Regulating the Expression of Flowering-Related Genes.

CCCH-type zinc finger proteins (ZFP) are a large family of proteins that play various important roles in plant growth and development; however, the functions of most proteins in this family are uncharacterized. In this study, a CCCH-type ZFP, AaZFP3, was identified in the floral organ of Adonis amurensis . Quantitative real-time PCR (qPCR) analysis revealed that AaZFP3 was widely expressed in the flowers of A. amurensis . Subcellular localization analysis showed that the AaZFP3 protein was mainly localized to the cytoplasm in tobacco and Arabidopsis . Furthermore, the overexpression of AaZFP3 promoted early flowering in Arabidopsis  under both normal and relatively low-temperature conditions. RNA-sequencing and qPCR analyses revealed that the expression of multiple key flowering-time genes was altered in transgenic Arabidopsis overexpressing AaZFP3 compared to wild-type. Of these genes, FLOWERING LOCUS T ( AtFT ) expression was most significantly up-regulated, whereas FLOWERING LOCUS C ( AtFLC ) was significantly down-regulated. These results suggest that the overexpression of AaZFP3 promotes early flowering in Arabidopsis by affecting the expression of flowering-time genes. Overall, our study indicates that AaZFP3 may be involved in flowering regulation in A. amurensis and may represent an important genetic resource for improving flowering-time control in other ornamental plants or crops.