Luciferase complementation imaging (LCI)

Luciferase complementation imaging (LCI) for testing the interaction of PIF5 with COP1 and SPA1 in N. benthamiana was performed as previously described with few modifications (Chen, et al. 2008). A. tumefaciens strain GV3101 was used for the injection of different constructs into N. benthamiana leaves. 1mM Luciferin was sprayed into the N. benthamiana leaves and kept in the dark for 5 min. Low-light cooled CCD camera (NightOWL IILB 983 NC 100, BERTHOLD) was used to capture luciferase luminesence. An exposure time of 2 min with 2×2 binning was used. Relative luciferase was equivalent to luminescence intensity / 0.2mm² leaf area.