Abstract
Although plastid development is dramatically changed through embryogenesis to seed germination, its biological relevance is not clearly understood. Here, we present evidences that plastid retrograde signaling pathways are involved in genetic programs of embryogenesis and seed germination. We have applied chemical genetics approach to Arabidopsis seed germination and identified E compounds from non-annotated chemical library. E compounds inhibit greening and expansion of cotyledons through ABA and GA signaling components. Genetic analysis revealed genome uncoupled loci, which are well characterized plastid retrograde signaling components, were also involved in the response to E compounds. Based on marker gene expressions for plastid retrograde signaling, E compounds were found to have both positive and negative action at different time points after germination. This can be explained by sequential activation (or repression) of two plastid retrograde pathways perturbed by E compounds during seed germination.
