Comparative transcriptomics for genes related to berberine and berbamine biosynthesis in Berberidaceae

Berberine and berbamine are bioactive compounds of benzylisoquinoline alkaloids (BIAs) present in Berberis species. The contents of berbamine are 20 times higher than berberine in leaf tissues in three closely related species: Berberis koreana, B. thunbergii and B. amurensis. Comparative transcriptome analyses were carried out with mRNAs from the leaf tissues of the three-species. In the vis-a-vis comparison of the transcriptomes of B. thunbergii and B. amurensis to those of B. koreana, B. thunbergii showed a consistently higher number of differentially expressed genes than B. amurensis in KEGG and DEG analyses. All genes encoding enzymes involved in berberine synthesis were identified to be variable among the three species. CYP80A was known to be involved in the berbamine synthesis, but the gene(s) encoding this enzyme was not identified in our results, which leaves an opportunity for further analysis for this enzyme. Methyltransferases and cytochrome P450 mono-oxidases (CYPs) are key enzymes for BIA biosynthesis. The current report contains the copy numbers and other genomic characteristics of the methyltransferases and CYPs in Berberis species. Thus, the contents of the current research will be valuable for molecular characterization for the medicinal utilization of the Berberis species.