An updated DNA barcoding tool for Aloe vera and related CITES-regulated species

Abstract

DNA barcoding has revolutionised the identification of illegally traded material of endangered species as it overcomes the lack of resolution encountered with morphological identification. Nonetheless, in recently evolved and highly diverse clades, such as the relatives of Aloe vera, the lack of interspecific sequence variation in standardised markers compromises the barcoding efficacy. We present a new DNA barcoding tool using 189 nuclear markers, optimised for aloes (Asphodelaceae, Alooideae). We built a comprehensive sequence reference dataset from taxonomically verified sources for >300 species and validated its reliability for identification using phylogenomic inference. Seven anonymised samples from verified botanical collections and ten plants seized at London Heathrow Airport were correctly identified to species level, including a critically endangered species from Madagascar. Commercially purchased samples were confirmed to be the species as advertised. An accurate, reliable DNA barcoding method for aloe identification introduces new assurance to regulatory processes for endangered plants in trade.