In Arabidopsis thaliana

the red and farred light photoreceptors phytochromes (PHYs) act to involve in regulating flowering. Phytochromobilin synthase (HY2) synthesizes the open chain tetrapyrrole chromophore which is essential to the lightsensing function of phytochromes

and it is a member of the ferredoxindependent bilin reductases (FDBRs). Here

we found a DsTDNA insertion line of  Arabidopsis thaliana for the gene encoding the most major ferredoxin (Fd2

At1g60950)

which can promote flowering in the process of growth both under longday and shortday conditions. In this report we show that loss of AtFd2 can promote flowering

AtFd2 interacts with AtHY2 in the chloroplast

and Fd2KO mutants are impaired in the responses mediated by phytochromes. Together

these results implicate that loss of AtFd2 may promote flowering by impairing the physiology function of phytochromes.