| Property | Value |
|---|---|
| BioDare ID | 13790763084422 |
| Author | Sawa, M. |
| Institution | Scripps Research Institute |
| License | CC_BY |
Precise timing of CONSTANS (CO) gene expression is necessary for day-length discrimination for photoperiodic flowering. The FLAVIN-BINDING, KELCH REPEAT, F-BOX 1 (FKF1), and GIGANTEA (GI) proteins regulate CO transcription in Arabidopsis. We demonstrate that FKF1 and GI proteins form a complex in a blue-light–dependentmanner. The timing of this interaction regulates the timing of daytime CO expression. FKF1 function is dependent on GI, which interacts with a CO repressor, CYCLING DOF FACTOR 1 (CDF1), and controls CDF1 stability. GI, FKF1, and CDF1 proteins associate with CO chromatin. Thus, the FKF1-GI complex forms on the CO promoter in late afternoon to regulate CO expression, providing a mechanistic view of how the coincidence of light with circadian timing regulates photoperiodic flowering.
To quantify mRNA of genes involved in flowering regulation, total RNA was isolated from 10-day-old seedlings using RNeasy plant mini kit (Qiagen). For synthesis of cDNA, 2.5 μg of total RNA was reverse-transcribed with the iScript cDNA synthesis kit (Bio-Rad). The synthesized cDNAs were amplified by using a Bio-Rad real-time detection system. The primers used for amplification of CO, FKF1 and GI were described previously (Nakamichi et al., 2007). The forward and the reverse primers for FT were 5’-CTGGAACAACCTTTGGCAAT-3’ and 5’-TACACTGTTTGCCTGCCAAG-3’, respectively. IPP2 expression was used as a normalization control (Imaizumi et al., 2005). The following program was used for PCR: 95°C for 90 seconds, 45 cycles of 95°C for 10 seconds, 55°C for 20 seconds, and 72°C for 20 seconds. Each PCR was repeated at least three times.
RT-PCR ()
Growth on MS plates 3% sucrose for 10.0 days (Sawa2007).
| Type | Duration (days) | Cycle (h) | Start | Duration | Spectrum | Source | Intensity |
|---|---|---|---|---|---|---|---|
| diurnal light | 10 | 24 | 0:00 | 16:00 | white | LED | 90 |
| Type | Duration (days) | Cycle (h) | Base (°C) | Warm (°C) | Warm start | Warm duration |
|---|---|---|---|---|---|---|
| constant temperature | 10 | 24 | 22 | -- | -- | -- |
Growth on MS 3% sucrose for 1.0 days (Sawa2007).
| Type | Duration (days) | Cycle (h) | Start | Duration | Spectrum | Source | Intensity |
|---|---|---|---|---|---|---|---|
| diurnal light | 1 | 24 | 0:00 | 16:00 | white | LED | 90 |
| Type | Duration (days) | Cycle (h) | Base (°C) | Warm (°C) | Warm start | Warm duration |
|---|---|---|---|---|---|---|
| constant temperature | 1 | 24 | 22 | -- | -- | -- |