Physiological and transcriptomic mechanisms of summer dormancy regulation in F. thunbergii bulbs synergistically induced by temperature and gibberellin modulators

Fritillaria thunbergii Miq. (F. thunbergii) is an important traditional Chinese medicinal herb. In the main producing areas of Zhejiang Province, the summer high-temperature period lasts 60–90 days, with ambient soil temperatures frequently reaching 20–25 °C. Under traditional open-air storage, these conditions cause 15–20% annual bulb rot loss. Consequently, industrial cultivation faces two distinct and opposing economic demands: (i) accelerating dormancy release to shorten breeding cycles and improve variety selection efficiency, and (ii) prolonging dormancy to extend safe over-summering storage and minimize post-harvest losses. Traditional single-temperature strategies cannot reconcile these bidirectional requirements. Synergistic regulation of temperature and plant hormones is an effective strategy to precisely control the dormancy period and reduce summer losses. In this work, F. thunbergii bulbs were treated with gibberellic acid and multiple GA synthesis inhibitors across different temperature gradients. Subsequently, by integrating phenotypic data, targeted LC-MS hormone profiling, and transcriptome sequencing, the hormone dynamics and underlying gene co-expression networks associated with dormancy were analyzed. Precise bidirectional regulation of the bulb dormancy period was achieved using this synergistic approach. Physiological and transcriptomic tests confirmed that 15 °C combined with GA 3 rapidly broke dormancy within approximately 43.7 days, whereas 15 °C combined with an inhibitor mixture prolonged dormancy to over 103.4 days by altering the endogenous GA 3 /ABA ratio and reprogramming carbohydrate metabolism pathways. This combined temperature-hormone regulation strategy exhibits great potential to ensure safe summer storage and improve cultivation efficiency for F. thunbergii , providing theoretical support and technical schemes for accelerated breeding and industrial production.