Co-expressed network analysis based on 289 transcriptome samples reveals methyl jasmonate-mediated gene regulatory mechanism of flavonoid compounds in Dendrobium catenatum

Flavonoids are momentous bioactive ingredients in orchid plant Dendrobium catenatum (D. catenatum), which are bioactive compounds with great medical and commercial potential. However, the accurate dissection of flavonoids profiling and their accumulation mechanism are largely unknown. In this study, methyl jasmonate (MeJA) treatment was used to investigate the change of flavonoids content and transcripts in two D. catenatum clones (A6 and B1). We identified 40 flavonoids using liquid chromatograph mass spectrometer (LC-MS). By weighted gene co-expressed network analysis (WGCNA) of flavonoids content and transcript expression of MeJA-treated samples, 37 hub genes were identified. Among them, DcCHIL, DcFLS, and DcDFR were highly correlation with two key transcription factors DcWRKY3/4 by correlation analysis of large-scale transcriptome data and above hub genes expression. Furthermore, transient overexpression of DcWRKY3/4 in tobacco leaves significantly increased the content of flavonoids. This study identified flavonoid profiling and built a new approach to mine regulatory mechanism of flavonoids in D. catenatum. These valuable flavonoids and gene resources will be key for understanding and harnessing natural flavonoids products in pharmaceuticals and foods industry of D. catenatum.