Profiling of Widely Targeted Metabolomics for the Identification of Secondary Metabolites in Heartwood and Sapwood of the Red-Heart Chinese Fir (Cunninghamia Lanceolata)

The chemical composition of secondary metabolites is important for the quality control of wood products. In this study, the widely targeted metabolomics approach was used to analyze the metabolic profiles of heartwood and sapwood in the red-heart Chinese fir (Cunninghamia lanceolata), with an ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry system. A total of 224 secondary metabolites were detected in the heartwood and sapwood, and of these, flavonoids and phenolic acids accounted for 36% and 26% of the components, respectively. The main pathways appeared to be differentially activated, including those for the biosynthesis of phenylpropanoids and flavonoids. Moreover, we observed highly significant accumulation of naringenin chalcone, dihydrokaempferol, pinocembrin, hesperetin, and other important secondary metabolites in the flavonoid biosynthesis pathway. Our results provide insight into the flavonoid pathway associated with wood color formation in Chinese fir that will be useful for further breeding programs.