ABSTRACT
Arabidopsis cryptochrome 2 (CRY2) and FLAVIN-BINDING, KELCH REPEAT, F-BOX 1 (FKF1) are blue light receptors mediating light regulation of growth and development, such as photoperiodic flowering. CRY2 interacts with a basic helix-loop-helix (bHLH) transcription factor CIB1 in response to blue light to activate the transcription of the flowering integrator gene FLOWERING LOCUS T (FT). CIB1, CIB2, CIB4 and CIB5 function redundantly to promote flowering in a CRY2-dependent way and form various heterodimers to bind to the non-canonical E-box sequence in the FT promoter. However, the function of CIB3 has not been described. We discovered that CIB3 promotes photoperiodic flowering independently of CRY2. Moreover, CIB3 does not interact with CRY2 but interacts with CIB1 and functions synergistically with CIB1 to promote transcription of the GI gene. FKF1 is required for CIB3 to promote flowering and enhances the CIB1-CIB3 interaction in response to blue light.
Manipulation of the Blue Light Photoreceptor Cryptochrome 2 in Tomato Affects Vegetative Development, Flowering Time, and Fruit Antioxidant Content
