Lophophora diffusa is a psychoactive plant of Cactaceae, morphologically similar to the mescaline-rich Lophophora williamsii but with a distinct alkaloid profile, posing significant challenges for law enforcement. Here, we sequenced the complete chloroplast genome of L. diffusa using PacBio high-throughput sequencing technology. The chloroplast genome is 115,689 bp in length and exhibits a highly derived quadripartite structure, featuring a large single-copy (LSC) region of 79,403 bp, a small single-copy (SSC) region of 32,910 bp, and a pair of significantly reduced inverted repeat (IR) regions of 1,688 bp each. It encodes 100 unique genes and has a GC content of 36.52%. Phylogenetic analysis robustly resolved the position of L. diffusa, formed a monophyletic Lophophora clade that includes L. fricii and L. williamsii; under the current sampling, this clade was resolved as sister to a group containing Mammillaria species. This study provides a foundational genomic resource for future development of precise molecular tools to distinguish L. williamsii from its relatives, thereby supporting forensic botany and international narcotics control efforts.
Zhang et al. (Fri,) studied this question.