Transcriptome and metabolome reveal the accumulation of secondary metabolites in different varieties of Cinnamomum longepaniculatum.

BACKGROUND: Cinnamomum longepaniculatum (Gamble) N. Chao ex H. W. Li, whose leaves produce essential oils, is a traditional Chinese medicine and economically important tree species. In our study, two C. longepaniculatum varieties that have significantly different essential oil contents and leaf phenotypes were selected as the materials to investigate secondary metabolism. RESULT: The essential oil content and leaf phenotypes were different between the two varieties. When the results of both transcriptome and metabolomic analyses were combined, it was found that the differences were related to phenylalanine metabolic pathways, particularly the metabolism of flavonoids and terpenoids. The transcriptome results based on KEGG pathway enrichment analysis showed that pathways involving phenylpropanoids, tryptophan biosynthesis and terpenoids significantly differed between the two varieties; 11 DEGs (2 upregulated and 9 downregulated) were associated with the biosynthesis of other secondary metabolites, and 12 DEGs (2 upregulated and 10 downregulated) were related to the metabolism of terpenoids and polyketides. Through further analysis of the leaves, we detected 196 metabolites in C. longepaniculatum. The abundance of 49 (26 downregulated and 23 upregulated) metabolites differed between the two varieties, which is likely related to the differences in the accumulation of these metabolites. We identified 12 flavonoids, 8 terpenoids and 8 alkaloids and identified 4 kinds of PMFs from the leaves of C. longepaniculatum. CONCLUSIONS: The combined results of transcriptome and metabolomic analyses revealed a strong correlation between metabolite contents and gene expression. We speculate that light leads to differences in the secondary metabolism and phenotypes of leaves of different varieties of C. longepaniculatum. This research provides data for secondary metabolite studies and lays a solid foundation for breeding ideal C. longepaniculatum plants.

Production of acteoside from Cistanche tubulosa by ß-glucosidase.

Acteoside and echinacoside are the major active components of Herba Cistanches. Facilitated ß-glucosidation was investigated as a means of increasing harvest of acteoside from Cistanche tubulosa. Fresh Cistanche tubulosa was treated by microwave moisture processing to inactivate enzymes. ß-Glucosidase is capable of hydrolyzing echinacoside for the production of acteoside, so six ß-glucosidases were compared for their efficiency, specific activities and kinetic parameters for conversion to acteoside. The acteoside and echinacoside content was found to be higher after microwave processing than by other previously reported methods. The results showed that ß-glucosidase isolated from microorganisms (Trichoderma sp.) had highly specific activity towards echinacoside, and there was a 4.83 fold increase in the concentration of acteoside after an incubation period of 2 h. This is the first report of the potential application of ß-glucosidases for the facilitated conversion of echinacoside to acteoside in Herba Cistanches extract.