Characteristics of , a Key Gene of Vernalization Pathway, Affects Flowering Time.

The tree peony ( section DC.) is the candidate flower in China, with abundant germplasm resources and high ornamental value. However, the short and concentrated flowering period severely restricted the improvement of the economic value of tree peonies. Based on the full-length transcriptome database of tree peonies, the (GenBank ID: OP341879), involved in the flowering regulation of tree peonies were identified and cloned for the first time. The was also characterized by bioinformatics methods, quantitative real-time PCR (qRT-PCR), and the establishment of a transgenic system. The expression levels of in seven different petals developmental stages were the highest at the initial flowering stage of the variant cultivar of 'Fengdan,' the initial decay stage of the normal flowering 'Fengdan,' and the half opening stage of the late flowering 'Lianhe.' Tissue-specific expression analysis showed that the relative expression levels of were the highest in sepals of both normal flowering 'Fengdan' and the late flowering 'Lianhe,' and the highest expression was in stamens of early flowering mutant 'Fengdan.' In addition, the flowering time of pCAMBIA2300- transgenic plants was significantly earlier than that of the wild-type, indicating that PoVIN3 could promote plant flowering. The results provide a theoretical basis for exploring the role of in the regulation of flowering in tree peonies.