Unraveling the multifaceted roles of the LncNAT1-GbCHS module in Ginkgo biloba for flavonoid biosynthesis and plant development

Flavonoids are the primary bioactive compounds in Ginkgo biloba leaves. However, the regulatory mechanisms underlying their biosynthesis remain incompletely understood. In this study, three G. biloba exhibiting significant differences in flavonoid content were selected from a total of 26 cultivars. Integrated metabolomic, lncRNA, and mRNA sequencing analyses identified GbCHS as a core gene involved in flavonoid biosynthesis. Overexpression of GbCHS markedly enhanced flavonoid accumulation, whereas virus-induced gene silencing (VIGS) of GbCHS resulted in a significant reduction in total flavonoid content, confirming its essential role in flavonoid biosynthesis. Notably, GbCHS-silenced G. biloba plants also exhibited a significant decrease in plant height, leaf weight, root length, and lateral root number. In contrast, Arabidopsis thaliana plants overexpressing GbCHS showed significant increases in plant height, leaf weight, root length, and lateral root number, indicating that this gene also promotes plant development. Furthermore, GbCHS was found to be partially complementary to the lncRNA LncNAT1. Overexpression of LncNAT1 in G. biloba calli significantly suppressed GbCHS expression and reduced total flavonoid content, whereas silencing LncNAT1 led to increased GbCHS expression, flavonoid accumulation, plant height, and leaf weight. Mechanistically, LncNAT1 represses GbCHS expression through the formation of an LncNAT1-GbCHS RNA duplex. Collectively, these findings reveal the multidimensional regulatory functions of the novel LncNAT1-GbCHS module in flavonoid biosynthesis and plant development in G. biloba.