Evaluation of chloroplast DNA barcoding markers to individualize Papaver somniferum for forensic intelligence purposes.

Abstract

The opium poppy, Papaver somniferum L., is a forensically important plant due to the medicinal and illegal uses for the milky latex stored in the pods. This latex contains the alkaloids morphine, codeine, and thebaine that are used for their analgesic properties and/or for synthesizing other opioids. However, these compounds are highly addictive and have caused a national opioid epidemic. Two other Papaver species, P. setigerum DC. and P. bracteatum Lindl., are also of forensic interest because they pose both forensic and legal issues. They are largely uncontrolled under the Controlled Substances Act, making these species a common defense strategy. Current morphological and chemical identification methods have been moderately successful but have drawbacks. There is also a lack of sequencing data available. Therefore, exploiting the genome using chloroplast DNA barcoding markers could help to accurately identify these species of interest when plant material is taken. This study screened and assessed the genetic variation both between species and within populations of P. somniferum in nine cpDNA barcode regions (ndhF-rpl32, petA-psbJ, rpl32-trnL, rps16-trnQ, trnE-trnT, trnH-psbA, trnL-trnF, rpl16 intron, and psbE-petL). Published reference genomes from the NCBI GenBank database were aligned and compared for an initial in silico screening. Additionally, ten P. somniferum seed samples from various vendors were sequenced and compared across samples and to published reference data at the various barcode regions of interest. This study showed that the regions trnH-psbA and petA-psbJ have promise for utility in individualization for both inter- and intra-species individualization of P. somniferum.