Table III.

The induction of the CBF TFs is diurnally gated

Expression of the CBF TFs was measured using qRT-PCR. Plants were grown under warm diurnal conditions under normal or low light in long days (16 h) before transfer to 4°C (or simulated control transfer) either at 2 h (ZT2) or 14 h (ZT14) after dawn. At both points, samples were harvested after 3 h at 4°C (Cm and Ce) and at 0 h (ZT2 and ZT14) and 3 h (ZT5 and ZT17) in control conditions. The sampling scheme is illustrated in Figure 5. Data are mean log2 ratios (n = 5). In low light, CBF1 was not detected at ZT2 generating infinite ratios (±inf).

CBFCold InductionMorning Versus Evening
Low LightNormal LightLow LightNormal Light
Cm–ZT2Cm–ZT5Ce–ZT14Ce–ZT17Cm–ZT2Cm–ZT5Ce–ZT14Ce–ZT17Cm–CeZT2–ZT14Cm–CeZT2–ZT14
CBF1+inf8.310.59.78.58.45.75.2−2.5−inf1.7−1.1
CBF29.78.68.59.110.38.54.96.92.81.53.1−2.3
CBF313.08.15.37.410.27.52.95.83.3−4.44.0−3.3