ABA INSENSITIVE4 promotes rather than represses PHYA-dependent seed germination in Arabidopsis thaliana

Light quality plays vital roles in the life cycle of plants. For example, in seeds of many species, light quality determines the levels of the gibberelins (GA) and abscisic acid (ABA) phytohormones, which promote and repress seed germination respectively (Seo et al., 2006). In Arabidopsis thaliana, the photoreceptors phytochrome A (PHYA) and PHYB distinguish between full light (rich in red wavelength; R) and shade light (rich in far-red wavelength; FR) to regulate seed germination (Lymperopoulos et al., 2018).