Exogenous GA3 promotes flower bud differentiation in Lycoris aurea by modulating hormone signaling and carbohydrate metabolism

Abstract

Lycoris aurea Herb. (golden spider lily) exhibits a prolonged vegetative phase and delayed flowering, limiting its ornamental and commercial value. Gibberellins, particularly GA 3 , are well-known regulators of flower bud differentiation in plants. Here, we investigated whether exogenous GA 3 could accelerate flower bud differentiation and shorten the flowering cycle in L. aurea . We combined histological observations, assessment of flowering rates, and measurements of carbohydrate and hormone levels with integrated transcriptomic and metabolomic analyses. This combination helped to elucidate the underlying mechanisms. GA 3 treatment promoted floral primordium differentiation and significantly increased flowering rates, with 200 mg/L GA 3 identified as the optimal concentration. Hormone profiling revealed dynamic changes in GA 3 , IAA, ABA, and ZR. Meanwhile, starch, sucrose, and SS accumulated during early differentiation. This accumulation reflects a metabolic shift that supports flower induction. Multi-omics analyses indicated that GA 3 activated GA signaling via GID1, up-regulated SAUR and SnRK2 in the IAA and ABA pathways, and suppressed JA-Ile signaling. Coordinated regulation of starch-metabolizing enzymes (PYG, AMY) and sucrose-related genes (HK, SUS, ostA/B) modulated carbohydrate flux, producing sugar signals such as glucose, trehalose, and isomaltose which facilitated flower development. These findings provide mechanistic insights into hormone-sugar crosstalk during flower induction and establish an actionable GA 3 -based strategy to enhance flowering in L. aurea , with broader implications for geophytic ornamental species.