Cytokinin-GLK regulatory module promotes the acquisition of photosynthetic activity and cell cycle re-entry in a green-flower mutant of Narcissus tazetta var. chinensis

Floral organs typically function as heterotrophic tissues, heavily reliant on imported photoassimilates for respiration and development. However, under specific genetic or environmental conditions, they can reacquire photosynthetic capabilities. Here, we identified a rare green-flower (GF) mutant in Narcissus tazetta var. chinensis that exhibits stable green coloration and leaf-like characteristics. Physiological assays demonstrated that this mutant undergoes a fundamental metabolic transition from a heterotrophic state to a photoautotrophic state, characterized by functional Photosystem II activity and positive net photosynthetic rates. Integrated transcriptomic and metabolomic analyses identified the ectopic accumulation of Cytokinins (specifically Zeatin) as the primary key promoter of this transition. High Cytokinin levels correlated strongly with the activation of GOLDEN2-LIKE ( NcGLK ) transcription factors, which coordinated chloroplast biogenesis, stomatal development, and cell cycle re-entry. We propose a “Cytokinin-GLK” regulatory module governing floral greening, providing new insights into floral organ plasticity and potential strategies for breeding long-lasting ornamental varieties.