Exogenous GA promotes flowering in (Orchidaceae) through bolting and lateral flower development regulation.

orchids have a high ornamental value, and their flower abundance and timing are both key horticultural traits regulated by phytohormones. All one-flowered have additional lateral buds in the apical bract that fail to develop. In this study, an exogenous gibberellin (GA) application promoted flowering of by inducing its early bolting instead of the floral transition of dominant flowers. Applying GA effectively promoted lateral flower differentiation, resulting in a two-flowered inflorescence. GA-promoted lateral flower formation involved GA interacting with indole-3-acetic acid (IAA) and cytokinins (CTKs), given the decreased CTK content and downregulated expression of CTK synthesis genes, the increased IAA content and downregulated expression of IAA degradation, and the upregulated expression of transport genes. Further, GA acted via , , and expressed in stage 5 to promote bolting, and via expression of , , and to promote flowering. This study provides insight into mechanisms regulating flower development of .