Cryptochrome 2 from Lilium × formolongi Regulates Photoperiodic Flowering in Transgenic Arabidopsis thaliana

The photoperiodic flowering pathway is essential for plant reproduction. As blue and ultraviolet-A light receptors, cryptochromes play an important role in the photoperiodic regulation of flowering. is an important cut flower that flowers within a year after seed propagation. Floral induction is highly sensitive to photoperiod. In this study, we isolated the gene ( ) from . The predicted LfCRY2 protein was highly homologous to other CRY2 proteins. The transcription of was induced by blue light. exhibits its highest diurnal expression during the floral induction stage under both long-day and short-day photoperiods. Overexpression of in promoted flowering under long days but not short days, and inhibited hypocotyl elongation under blue light. Furthermore, LfCRY2 was located in the nucleus and could interact with CONSTANS-like 9 (LfCOL9) and CRY-interacting basic-helix-loop-helix 1 (AtCIB1) in both yeast and onion cells, which supports the hypothesis that hastens the floral transition via the CIB1-CO pathway in a manner similar to . These results provide evidence that plays a vital role in promoting flowering under long days in .