Fig. 4.

FHY1 modulates seed germination under FR independently of phyA through association and regulation of a unique direct target gene, whose knockout line is reported to be resistant to salt. (A) The fhy1-1 mutant exhibits a higher germination rate compared with wild-type (Ler) and the phyA-1 mutant upon salt treatment under FR. Seeds were spread on Murashige and Skoog plates without or with NaCl (167 mM and 194 mM) and grown under FR for 4 d. Arrowheads mark germinated seeds. (B) Statistics of seed germination are shown in A. NG, not germinated. (C) FHY1 but not phyA associates with the promoter of AFP4. (Scale bar, 500 bp.) (D) ChIP-PCR shows that FHY1 associates with AFP4 promoter independent of phyA. (E) FHY1 but not phyA is crucial for AFP4 expression under FR. Transcripts were normalized to UBQ1. The gray lines indicate ±1.5-fold change. Materials used in D and E were treated as described in Fig. 2. All error bars in this figure represent ±SD (n = 3) of three biological replicates.