<i>Ginkgo biloba GbbHLH13</i> transcription factor regulates flavonoid biosynthesis

Abstract

Ginkgo biloba is the oldest living plant on Earth and one of the most widely used natural medicines worldwide. Flavonoids extracted from G. biloba have been shown to have protective effects against cardiovascular and cerebrovascular diseases. The bHLH transcription factors (TFs) are among the most important families of transcription factors in plants, playing a crucial role in regulating plant growth, development, and secondary metabolism. In this study, GbbHLH13 was isolated and identified. It encodes a protein consisting of 732 amino acids, and transient expression assays in tobacco indicated that GbbHLH13 is localized in the nucleus. Exogenous hormone treatments revealed that the expression of GbbHLH13 is affected by methyl jasmonate (MeJA) and abscisic acid (ABA). Transient overexpression experiments further showed that it upregulates the transcription levels of flavonoid metabolism-related genes PAL, CHI, and C4H, suggesting that GbbHLH13 may be involved in flavonoid biosynthesis.