Transcription factor PcERF114 is involved in the regulation of flavonoid accumulation of Polygonatum cyrtonema Hua

Polygonatum cyrtonema Hua (P. cyrtonema), a traditional medicinal herb, is renowned for its high metabolite content. Previous studies have found that APETALA2/Ethylene Responsive Factor (AP2/ERF) plays a vital role in the metabolisms of P. cyrtonema, while the regulatory mechanism of PcAP2/ERFs in the flavonoid accumulation remains unclear. A total of 53 PcAP2/ERFs were identified from the full-length transcriptome. The expression analysis of PcAP2/ERFs in different age section rhizomes and different tissue sections showed that PcERF114 was associated with flavonoid accumulation and located in the nucleus. The flavonoid content was significantly up-regulated with the transient overexpression of PcERF114, and significantly down-regulated with virus-induced gene silencing of PcERF114 in the P. cyrtonema leaves. Meanwhile, an integrative analysis of transcriptome and metabolome revealed that differentially expressed genes and differentially accumulated metabolites of transgenic leaves were closely related to the flavonoid biosynthesis pathway, and PcCHS1 was identified as a flavonoid biosynthesis-related key gene by WGCNA, qRT-PCR, and KEGG analysis. Overexpression of PcERF114 in the stable transgenic hairy roots and transiently transformed rhizomes increased the PcCHS1 expression, and the transient co-transformation of overexpressing PcERF114 and PcCHS1 promoted flavonoid accumulation, suggesting that PcERF114 may affect the expression of PcCHS1, thereby promoting the flavonoid accumulation of P. cyrtonema. The results provided a reference for further functional studies of secondary metabolism biosynthesis-related genes in medicinal plants.