Figure 4.

SAUR50 and SAUR16 Are Activated by the Expression of TCP4-like Genes to Promote Cotyledon Opening.

(A) Expression of SAUR16 and SAUR50 in cotyledons is light induced and is dependent on the presence of TCP4-like genes. Expression levels of the indicated SAURs in cotyledons of Col and the indicated tcp mutants grown in the dark (D) or after light treatment for 3 h were determined by RT-qPCR. Data are shown as the mean ± sd of three biological replicates. Statistical analysis was performed using two-tailed Student’s t test against Col (DL3 h): ns, P > 0.05; *, P < 0.05. DL3 h, 3 h after light exposure.

(B) and (C) Overexpression of SAUR50 rescues the delayed cotyledon opening phenotypes of tcp3 tcp4 tcp10 (tcp) mutants during the dark-to-light transition. (B) Photographs showing cotyledons of the indicated lines taken in the dark or 4 h after light exposure. (C) Four-day-old dark-grown seedlings were illuminated with white light, and cotyledon opening percentages at the indicated time after light exposure were scored. Data are shown as the mean ± se. D, dark; D to L, dark to light.