Chloroplast genome sequences of Artemisia maritima and Artemisia absinthium: Comparative analyses, mutational hotspots in genus Artemisia and phylogeny in family Asteraceae.

Artemisia L. is a complex genus of medicinal importance. Publicly available chloroplast genomes of few Artemisia species are insufficient to resolve taxonomic discrepancies at species level. We report chloroplast genome sequences of two further Artemisia species: A. maritima (151,061 bp) and A. absinthium (151,193 bp). Both genomes possess typical quadripartite structure comprising of a large single copy, a small single copy and a pair of long inverted repeats. The two genomes exhibited high similarities in genome sizes, gene synteny, GC content, synonymous and non-synonymous substitutions, codon usage, amino acids frequencies, RNA editing sites, microsatellites, and oligonucleotide repeats. Transition to transversion ratio was <1. Maximum likelihood tree showed Artemisia a monophyletic genus, sister to genus Chrysanthemum. We also identified 20 highly polymorphic regions including rpoC2-rps2, trnR-UCU-trnG-UCC, rps18-rpl20, and trnL-UAG-rpl32 that could be used to develop authentic and cost-effective markers to resolve taxonomic discrepancies and infer phylogenetic relationships among Artemisia species.

Development of a PCR High-Resolution Melt Assay for Artemisia absinthium (Wormwood) and a Triplex Assay with Two Additional "Unregulated Legal High" Species Datura stramonium (Jimson Weed) and Merremia tuberosa (Hawaiian Woodrose).

Artemisia absinthium (wormwood), a common ingredient in absinthe, contains the compound thujone, which is unregulated by the U.S. Drug Enforcement Agency. Thujone can cause an "unregulated legal high" in higher concentrations. The European Union limits thujone from Artemisia species to 35 mg/kg while the U.S. Food and Drug Administration requires less than 10 ppm to be "thujone-free." However, individuals can smoke or ingest A. absinthium in different forms. This study developed a polymerase chain reaction (PCR) high-resolution melt (HRM) assay to detect and identify A. absinthium based on primer specificity, sensitivity, repeatability, and robustness. A triplex assay was performed with three "unregulated legal high" species: Datura stramonium, Merremia tuberosa, and A. absinthium; the PCR HRM assay detected and identified each plant at melt temperatures 77.42 ± 0.20°C, 83.88 ± 0.22°C, and 87.77 ± 0.15°C, respectively. The primer set developed distinguished A. absinthium from a variety of plant species and was successfully triplexed.