LncNAT11-GbMYB11-GbF3'H/GbFLS module mediates flavonol biosynthesis to regulate salt stress tolerance in Ginkgo biloba.

Abstract

Flavonols are important secondary metabolites that enable plants to resist environmental stresses. Although MYB regulation of flavonol biosynthesis has been well studied, the lncRNA-MYB networks involved in regulating flavonol biosynthesis remain unknown. Ginkgo biloba is rich in flavonols, which are the most important medicinal components. Based on multi-omics data and phylogenetic trees, we identified GbMYB11 as a potential key transcription factor regulating flavonol biosynthesis. Overexpression and VIGS experiments confirmed that GbMYB11 acts as a pivotal positive regulator in flavonol biosynthesis. In the transcriptome of calli overexpressing GbMYB11, we identified significant upregulation of GbF3'H and GbFLS in the flavonol biosynthetic pathway. Yeast one-hybrid and dual-luciferase assays demonstrated that GbMYB11 enhances the expression of GbF3'H and GbFLS by binding to their promoters. Interestingly, we identified LncNAT11, an antisense lncRNA complement to GbMYB11, which negatively regulates flavonol biosynthesis by repressing the expression of GbMYB11. Consequently, we established the LncNAT11-GbMYB11-GbF3'H/GbFLS module as a critical regulator of flavonol biosynthesis in G. biloba, and further elucidated that this module can mitigate the accumulation of reactive oxygen species by modulating flavonol biosynthesis during salt stress. These findings unveil a novel mechanism underlying flavonol biosynthesis and a lncRNA-MYB mediated salt stress tolerance strategy in plants.