Integrated analysis of transcriptomics and metabolomics of Dendrobium officinale flowers at different developmental stages

Dendrobium officinale is an edible medicinal herb. Its flowers contain various nutrients and active compounds, the abundance of which differs significantly across developmental stages. However, the molecular mechanisms underlying these variations remain poorly understood. This study employed combined transcriptomic and metabolomic analyses to investigate changes in gene expression and metabolite concentrations in Dendrobium flowers and buds. The analysis identified 2767 differentially expressed genes between the bud (group B) and flower (group F) stages, with 902 up-regulated and 1865 down-regulated in group B relative to group F. The number of differentially abundant secondary metabolites was 221, including 113 up-regulated and 108 down-regulated metabolites. The differential metabolites primarily consisted of lipids and lipid-like molecules, organic heterocyclic compounds, organic acids, and their derivatives, phenylacetones and polyketides, organic oxides, benzene ring-type compounds, hydrocarbons, and alkaloids with their derivatives. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of the differentially expressed genes and metabolites revealed enrichment in pathways related to phytohormone signaling, phenylpropanoid biosynthesis, and zeaxanthin biosynthesis. Verification of 15 genes through quantitative real-time PCR (qRT-PCR) confirmed the accuracy of the transcriptomic analysis. Taken together, these findings contribute to an improved understanding of the nutritional and pharmacological characteristics of Dendrobium officinale flowers at different developmental stages.