Recent advances in the juvenile-to-adult phase transition

The transition from the juvenile to adult vegetative phase in Arabidopsis thaliana is a fundamental developmental process that integrates morphological and physiological maturation. Despite extensive study, how vegetative phase change is regulated and how this phase transition is coordinated with plant physiology remain incompletely understood. This review synthesizes recent advances in the molecular regulation and physiological functions of vegetative phase change. We summarize how developmental traits-such as leaf shape, trichome distribution, and margin serration-are controlled through distinct downstream targets of the age-dependent miR156-SPL pathway. We further highlight emerging insights into how epigenetic factors dynamically modify chromatin states of key regulatory genes through histone modifications and how hormonal pathways modulate phase transitions in response to internal and environmental cues. Finally, we discuss the physiological consequence of vegetative phase change, including its impacts on photosynthesis, resource allocation, stress adaptation, and pathogen resistance. Collectively, these findings define vegetative phase change as an integrative developmental program that links genetic, epigenetic, hormonal, and physiological networks to coordinate plant maturation and environmental adaptability.