Table 2.
Characterization of the selected transcription factors and the TFBSs with unknown transcription factors that were identified in the promoter regions of Ppd-B1
| Family | Transcription factors/TFBSs with unknown TF | Description |
|---|---|---|
| AP2 | AINTEGUMENTA (ANT) | ANT initiates floral organ development [87]. It was shown to play a critical role in regulating the ovule and female gametophyte development [88]. |
| C2H2 | RESPONSIVE TO HIGH LIGHT 41 (Zat2) | Zat12 was originally isolated as a light stress-response cDNA [89]; then, it was suggested to be able to regulate transcripts involved in the response to high-light, cold and oxidative stress [90]. |
| MADS box/MIKC | AGL19 | AGL19 controls (promotes) flowering downstream of a cold-perception pathway and acts independently of FT and SOC1 [42]. |
| MADS box/MIKC | FLOWERING LOCUS C (FLC) | FLC acts as an inhibitor of flowering [45]. |
| MADS box/MIKC | MAF2 (AGL31) | MAF2 (AGL31), a paralog of FLC, is another flowering repressor that acts in non-inductive photoperiods [46, 47]. |
| MADS box/MIKC | AGL69 (MAF5) | MAF5 is normally repressed. Overexpression of MAF5 under a non-inductive day length causes late-flowering [48]. |
| MADS box/MIKC | AGL68 (MAF4) | MAF4 represses the transition to flowering [49, 50]. |
| MADS box/MIKC | FLM (AGL27, MAF1) | FLM acts as a flowering inhibitor [51]. |
| MADS box/MIKC | AGL6 | AGL6 was suggested to be able to act as a flowering repressor or activator, depending on the context [43]. |
| MADS box/MIKC | AGL14 (XAANTAL2, XAL2) | XAL2 is essential for flowering induction. XAL2 promotes flowering in response to different signals and is important for the maintenance and differentiating of flowering meristems [44]. |
| MADS box/MIKC | AGAMOUS-like 15 (AGL15) | AGL15 and AGL18 are floral transition repressors. The agl15 agl18 mutants were characterized by a partial suppression of the photoperiod pathway [52]. |
| MADS box/MIKC | AGAMOUS-like 18 (AGL18) | |
| Lyase Aromatic | Phenylalanine Ammonia-Lyase (PAL1) | PAL1 is a light response element. These motifs are conserved at similar positions in several elicitor or light-responsive genes from different species [91]. |
| – | RBCSGBOXPS | RBCSGBOXPS binding site, identified in Parsley, is involved in light responsiveness [92]. |
| – | REBETALGLHCB21 | REBETALGLHCB21, first found in the Lemna dibba Lhcb genes, is necessary for phytochrome regulation. These elements are likely to function by repressing the promoter activity in the dark [93]. |
| – | SORLIP5AT | SORLIP5AT are PhyA-induced motifs that are overrepresented in light-induced genes. These elements, which predominate in the early responsive promoters, are more likely to have the fewest steps in the signal transduction cascade to gene expression [66]. |
| – | MNF1ZMPPC1 | MNF1ZMPPC1 is involved in the light-dependent transcriptional control of gene expression [94]. |