Transcriptomic and metabolomic insight into regulation of Cardiocrinum giganteum seed dormancy release induced by...

Seed dormancy release of Cardiocrinum giganteum by variable temperature stratification is mainly regulated by hormones and carbohydrate metabolism. Cardiocrinum giganteum, a perennial herbaceous bulbous plant with ornamental, edible, and unique medicinal value, is a scarce resource endemic to East Asia. However, a 17-18-month seed morphophysiological dormancy period limits its development and utilization. Under controlled laboratory conditions, variable temperature stratification can reduce the dormancy-releasing period of C. giganteum seeds, yet the underlying molecular regulatory mechanisms remain unclear. To elucidate the dormancy release mechanism in C. giganteum seeds, variable temperature stratification (25 °C/15 °C (60 d) → 15 °C/4 °C (90 d) → 4 °C (60 d)) was applied, followed by transcriptomic, metabolomic, and UPLC-MS/MS analyses to identify stage-specific differentially expressed genes. WGCNA further revealed key gene co-expression networks in metabolic pathways across four dormancy stages. Variable temperature stratification could significantly improve the embryo development and germination rate of C. giganteum seeds, and the dormancy period could be shortened to 7 months. The content of glucose, gibberellin, and trans-zeatin increased, while starch and abscisic acid decreased during seed variable temperature stratification. Transcriptomic, metabolomic, and WGCNA analyses indicated that 16 hub genes and 24 transcription factors were involved in the metabolism of glucose and trans-zeatin metabolism; 14 hub genes and 8 transcription factors were associated with abscisic acid and starch metabolism. Furthermore, key genes and metabolites involved in metabolism pathways such as the glycolysis pathway, tricarboxylic acid cycle, and pentose phosphate pathway were identified. Seed dormancy release of C. giganteum by variable temperature stratification is mainly regulated by hormones and carbohydrate metabolism.