Figure 4.

Graphic summary. ET represses cotyledon opening via ETHYLENE INSENSITIVE3 (EIN3) and EIN3-LIKE1 (EIL1). Retrograde signals, induced by lincomycin, repress cotyledon separation via two pathways: a GENOMES UNCOUPLED1 (GUN1)-dependent repression of photomorphogenesis-inducing factors (e.g. GOLDEN2-LIKE1, GLK1), and a GUN1-independent induction of EIN3/EIL1 co-targets. “X” represents a repressor of cotyledon separation downstream of EIN3/EIL1 that is induced by ET and by chloroplast signals independently of GUN1. X is likely a gene (or set of genes) regulated redundantly by EIN3 and EIL1.