Comparative Proteomics Analysis Reveals the Molecular Mechanisms Underlying the Accumulation Difference of Bioactive Constituents in Taxilli Herba from Two Hosts

Taxilli Herba (TH) is famous for semi-parasitic feature, with hundreds of host species. The content of bioactive constituents varies in TH from different hosts. To gain insight into the molecular mechanisms of the synthesis and accumulation of bioactive constituents in TH from different hosts, we performed proteomics combined with metabolomics to investigate TH from two common hosts of Morus alba L. and Liquidambar formosana Hance. Tandem mass tag (TMT)-based quantitative proteomics were used for analysis. A total of 533 differentially expressed proteins were detected, of which 259 were significantly up-regulated and 274 significantly down-regulated in expression levels. DEPs were shown to be mostly engaged in cellular process and metabolic process by GO analysis. DEPs were considerably abundant in amino acid metabolic pathways, according to KEGG pathway analysis. 16 bioactive constituents were quantitatively determined by ultrafast liquid chromatography simultaneously coupled with triple quadrupole/linear ion trap tandem mass spectrometry (UFLC-QTRAP-MS/MS). Meanwhile, the changes in the contents of 16 bioactive constituents were mostly compatible with the expression patterns of relevant structural proteins. The results of this study will provide basic information about the role of protein in the secondary metabolism biosynthesis pathway and the molecular mechanism of the quality formation of TH.