| Description |
The secret of tree longevity is a fascinating puzzle. Ginkgo biloba is one of the most enigmatic plants, renowned for its remarkably long-life span. Although previous studies have suggested the significance of secondary metabolites in the longevity of G. biloba, the regulatory mechanism in old ginkgo trees remains unclear. Here, we used 1-1200-year- old ginkgo trees to identify GbDAL1 as a critical age regulator controlling flavonoid synthesis. GbDAL1 not only directly inhibits flavonoid synthesis by regulating GbFLS expression, but also suppresses the expression of GbMYB28 to attenuate GbFLS transcription. Overexpression of GbDAL1 reduced flavonoid biosynthesis and made the transgenic plants more sensitive to stress (e.g., salt, drought, and UV-B), indicating that GbDAL1 acts as a crucial negative regulator, suppressing flavonol synthesis and stress tolerance. Interestingly, GbDAL1 interacts with the gibberellin signaling protein, GbGAI, to maintain a certain expression level in old trees. This process aids in diminishing the negative impact of GbDAL1 on the resistance of older trees. More importantly, certain secondary metabolites, such as flavonoids and phenolic compounds, can progressively accumulate in the woody tissue with age to enhance the resistance abilities of old trees. Taken together, our findings uncover previously unknown regulation mechanisms of flavonoid biosynthesis in old trees, highlighting the age-dependent regulation of secondary metabolites in long-lived trees. |
