The chromosome-level reference genome of Coptis chinensis provides insights into genomic evolution and berberine biosynthesis

Coptis chinensis Franch, a perennial herb, is mainly distributed in southeastern China. The rhizome of C. chinensis hasbeen used as a traditional medicine for more than 2000 years in China and many other Asian countries. Thepharmacological activities of C. chinensis have been validated by research. Here, we present a de novo high-qualitygenome of C. chinensis with a chromosome-level genome of ~958.20 Mb, a contig N50 of 1.58 Mb, and a scaffold N50of 4.53 Mb. We found that the relatively large genome size of C. chinensis was caused by the amplification of longterminal repeat (LTR) retrotransposons. In addition, a whole-genome duplication event in ancestral Ranunculales wasdiscovered. Comparative genomic analysis revealed that the tyrosine decarboxylase (TYDC) and (S)-norcoclaurinesynthase (NCS) genes were expanded and that the aspartate aminotransferase gene (ASP5) was positively selected inthe berberine metabolic pathway. Expression level and HPLC analyses showed that the berberine content was highestin the roots of C. chinensis in the third and fourth years. The chromosome-level reference genome of C. chinensisprovides important genomic data for molecular-assisted breeding and active ingredient biosynthesis.