Genetic and signaling pathways of flowering regulation in rice (Oryza sativa L.)

Flowering time is of great significance for crop reproduction, yield, and regional adaptability, which is intricately regulated by various environmental cues and endogenous signals. Photoperiod is a key flowering regulating factor due to its relatively high concern in the same geography, while other factors change year over year. Photoperiodic flowering time is controlled by a complex genetic network, which is regulated by florigen. RICE FLOWERING LOCUS T 1 (RFT1) is the closest homologue of Heading date 3a (Hd3a), which is thought to encode a mobile flowering signal and promote floral transition under short-day (SD) conditions in rice. Recent molecular genomic advancement revealed how to identify the molecular nature of florigen, its function, expression, and how to diversify its regulatory pathway. Here, we summarized the recent understanding of flowering time regulation mainly focused on rice Hd3a, its molecular function, expression, and diversified photoperiodic regulatory pathways under short-day and long-day (LD) conditions.