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).
| CBF | Cold Induction | Morning Versus Evening | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low Light | Normal Light | Low Light | Normal Light | |||||||||||||||||||
| Cm–ZT2 | Cm–ZT5 | Ce–ZT14 | Ce–ZT17 | Cm–ZT2 | Cm–ZT5 | Ce–ZT14 | Ce–ZT17 | Cm–Ce | ZT2–ZT14 | Cm–Ce | ZT2–ZT14 | |||||||||||
| CBF1 | +inf | 8.3 | 10.5 | 9.7 | 8.5 | 8.4 | 5.7 | 5.2 | −2.5 | −inf | 1.7 | −1.1 | ||||||||||
| CBF2 | 9.7 | 8.6 | 8.5 | 9.1 | 10.3 | 8.5 | 4.9 | 6.9 | 2.8 | 1.5 | 3.1 | −2.3 | ||||||||||
| CBF3 | 13.0 | 8.1 | 5.3 | 7.4 | 10.2 | 7.5 | 2.9 | 5.8 | 3.3 | −4.4 | 4.0 | −3.3 | ||||||||||