The hypocotyls of dicotyledons and mesocotyls of monocotyledons are important morphological hallmarks for skotomorphogenesis and photomorphogenesis. Their elongation is promoted by darkness and their growth is inhibited by light illumination. It has been established that the morphogenesis of hypocotyls in the model species Arabidopsis was cooperatively regulated by genes in light signaling and also other plant hormone signaling pathways. The homologs of these genes in crop species have been implicated with ...