A chromosome-level genome assembly of anesthetic drug-producing Anisodus acutangulus provides insights into its evolution and the biosynthesis of tropane alkaloids.

Tropane alkaloids (TAs), which are anticholinergic agents, are an essential class of natural compounds. There is a growing demand for these compounds with anesthetic, analgesic, and spasmolytic effects. Anisodus acutangulus is a TA-producing plant (family Solanaceae) that was used as an anesthetic in ancient China. In this study, a high-quality chromosome-scale A. acutangulus genome was assembled, with a contig N50 of up to 7.4 Mb. In A. acutangulus, a recent whole-genome duplication event occurred after the divergence from other Solanaceae plants, which resulted in the duplication of the ADC1 and UGT genes involved in TA biosynthesis. The catalytic activities of H6H enzymes were determined for three Solanaceae plants. On the basis of evolution and co-expressed genes, AaWRKY11 was selected for further analyses, which revealed the encoded transcription factor promotes TA biosynthesis by activating AaH6H1 expression. The findings of this study may provide useful insights into genomic evolution related to TA biosynthesis, with possible implications for the genetic manipulation of TA-producing plants.