Differentiation of Siam weed (Chromolaena odorata (L.) R.M. King & H. Rob.) and morphologically related species in Asteraceae by ITS barcode coupled with high resolution melting analysis (HRM)

Abstract

© 2020 Elsevier B.V. Siam weed (Chromolaena odorata (L.) R.M. King & H. Rob.) is a commercially viable plant that has various pharmacological properties including hemostasis and wound healing. Three other plant species as Praxelis (Praxelis clematidea R.M. King & H. Rob.), Goat weed (Ageratum conyzoides L.) and Crofton weed (Ageratina adenophora (Spreng.) R.M. King) in the same family have similar morphological characteristics. Misidentification of processed materials can occur in the absence of a skilled taxonomist. These four plants can often be found in close proximity, leading to erroneous sample collection and misleading results. DNA identification through molecular techniques is an accurate method for correctly identifying and differentiating Siam weed to control the quality of product development. Two primers (ITS1A and ITS1B) were designed based on the barcode (Bar) locus of the internal transcribed spacer (ITS) region. High resolution melting (HRM) analysis (Bar-HRM) was performed to acquire melting shapes and melting temperatures (Tm) to discern the four plant species. Bar-HRM using ITS1A and ITS1B showed differences in melting shapes among the four species. The method employing ITS1A distinguished the four species with higher accuracy than ITS1B. The Tm values of each species obtained from Bar-HRM using ITS1A ranged from 82.54 °C to 86.26 °C. Bar-HRM using ITS served as a rapid and reliable tool for species differentiation among Siam weed, Praxelis, Goat weed and Crofton weed.