Figure 1.

LUH Inhibits Light-Dependent Seed Germination.

(A) The T-DNA insertion sites for two luh mutants are indicated by inverted triangles. Black boxes indicate the LUH exons, white boxes indicate the untranslated regions, and the translation start and termination sites are indicated by ATG and TAG, respectively.

(B) The phyB_off and phyB_on light treatment schemes. Dry seeds were sterilized and irradiated with a far-red light pulse (5 min, 2.59 μmol·m⁻²·s⁻¹) for the phyB_off condition or with a far-red light pulse followed by a red light pulse (5 min, 11.5 μmol·m⁻²·s⁻¹) for the phyB_on condition. Irradiated seeds were then incubated in the dark for various periods. Germination assays were performed on seeds incubated in the dark for 96 h and 4 d, whereas gene expression analysis was performed on seeds incubated in the dark for 12 h.

(C) and (D) The two luh mutants germinate in the phyB_off condition. This is rescued by the expression of Myc-tagged LUH under the 35S promoter (LUH-OX/luh-3) (sd, n = 3 biological replicates).

(E) and (F) Wild-type and luh-3 seeds show comparable levels of PIF1 mRNA (E) (sd, n = 3 biological replicates) and protein (F) under the phyB_off condition.

(G) and (H) Red light neither alters LUH mRNA levels (G) (sd, n = 3 biological replicates) nor LUH protein stability (H).