Pruning improves seedling development and bioactive secondary metabolite accumulation in the leaves of Ginkgo biloba

Key message Pruning could significantly promote branch formation, root development, and leaf growth, especially, improve flavonol glycoside and terpene lactones accumulation in leaves of ginkgo seedlings. Abstract Ginkgo biloba , an economically important tree species, is used as a medicinal plant due to the various secondary metabolites in its leaves. Pruning is the process of cutting branches to facilitate vegetative or reproductive growth. However, little is known about the effects of pruning on active compound accumulation in medicinal plants. Here, we found that after pruning 2-year-old ginkgo seedlings, branch number, ground diameter, and root size increased significantly; in particular, leaf size and crack number increased dramatically. Importantly, after pruning, fresh and dry leaf weights increased. Meanwhile, the total flavonoid, flavonol glycoside, and isorhamnetin contents of the leaves increased significantly, by about 24%, 20%, and 22%, respectively, and the contents of terpene lactones in leaves and roots increased by 8% and 28%, respectively. Through quantitative real-time polymerase chain reaction (qRT-PCR) analysis, we detected upregulation of flavonoid synthesis-associated genes, including chalcone synthase ( CHS ), flavonoid 3′-hydroxylase ( F3'H ), flavonol synthase ( FLS ), flavanone 3-hydroxylase ( F3H ) and anthocyanin synthase ( ANS ), and the terpene lactone synthesis-related genes acetyl-CoA C-acetyltransferase ( AACT ) in leaves after pruning. These results indicate that pruning promotes leaf growth and bioactive compound accumulation in ginkgo seedlings.