Uncovering the Non-Flowering Mystery of Epipremnum aureum

Epipremnum aureum, a popular houseplant belonging to Araceae family of angiosperms does not flower in wild or cultivation. The underlying mechanisms affecting its flowering have remained a mystery. Here we show that its non-flowering is due to the deficiency of bioactive phytohormone gibberellic acids (GAs). We employed next-generation sequencing technique to build its transcriptome and then performed differentially expressed gene analysis to investigate the potential causes. It is known that transition from juvenile to adult phase is a prerequisite for flowering, and that the gene network controlling this process is highly conserved across species. Thus we utilized a group of flower-related genes from Arabidopsis and examined the expressions of their orthologs in vertical growth (VG, adult) and horizontal growth (HG, juvenile) E. aureum plants to understand the molecular basis of its non-flowering nature. Results showed that the transcripts of floral meristem identity gene EaLFY and GA biosynthetic gene EaGA3ox1 were absent in both plants, suggesting that the deficiency of bioactive GAs may be responsible for its non-flowering. Supporting to this hypothesis, all three bioactive GAs were either undetectable or low in both VG and HG plants,  and GA₃ treatment triggered flowering in both plants. GA₃ treatment was found to induce EaLFY expression by relieving the activity of flowering repressor EaGNC resulting in the activation of EaAGL17, EaAP1 and other floral meristem identity genes. This study resolves the mystery of why E. aureum fails to flower, and reveals the positive role of GAs on floral transition in perennials.