DNA barcoding of vouchered xylarium wood specimens of nine endangered Dalbergia species

Abstract

ITS2+ trnH - psbA was the best combination of DNA barcode to resolve the Dalbergia wood species studied. We demonstrate the feasibility of building a DNA barcode reference database using xylarium wood specimens. The increase in illegal logging and timber trade of CITES-listed tropical species necessitates the development of unambiguous identification methods at the species level. For these methods to be fully functional and deployable for law enforcement, they must work using wood or wood products. DNA barcoding of wood has been promoted as a promising tool for species identification; however, the main barrier to extensive application of DNA barcoding to wood is the lack of a comprehensive and reliable DNA reference library of barcodes from wood. In this study, xylarium wood specimens of nine Dalbergia species were selected from the Wood Collection of the Chinese Academy of Forestry and DNA was then extracted from them for further PCR amplification of eight potential DNA barcode sequences (ITS2, matK, trnL, trnH-psbA, trnV-trnM1, trnV-trnM2, trnC-petN, and trnS-trnG). The barcodes were tested singly and in combination for species-level discrimination ability by tree-based [neighbor-joining (NJ)] and distance-based (TaxonDNA) methods. We found that the discrimination ability of DNA barcodes in combination was higher than any single DNA marker among the Dalbergia species studied, with the best two-marker combination of ITS2+trnH-psbA analyzed with NJ trees performing the best (100% accuracy). These barcodes are relatively short regions (<350 bp) and amplification reactions were performed with high success (≥90%) using wood as the source material, a necessary factor to apply DNA barcoding to timber trade. The present results demonstrate the feasibility of using vouchered xylarium specimens to build DNA barcoding reference databases.

Palisandri in sorodniki iz rodu Dalbergia na seznamu CITES

“…V zadnjem času raziskave DNK profilov razvijajo tudi za razlikovanje vrst iz rodu Dalbergia (Hartvig et al, 2015;Hassold et al, 2016). Nedavno so kitajski znanstveniki pokazali, da je mogoče sestaviti referenčno bazo DNA profilov in razlikovati vrste iz rodu Dalbergia, ki jih ni mogoče razlikovati z drugimi metodami (Yu et al, 2017).…”

“…Using mass spectrometry (Lancaster & Espinoza, 2012) or analysis of wood using a Direct Analysis in Real Time (DART) and TimeOf-Flight Mass Spectrometer (TOFMS) can assist in making species determinations of Dalbergia (Espinoza et al 2015). Moreover, DNA barcoding has also been recently and successfully used for differentiating endangered Dalbergia species (Yu et al, 2017).…”

A Computer-aided Method for Identifying the Presence of Softwood Growth Ring Boundaries

“…The traditional methods of wood identification include manual comparison, dichotomous keys, multiple entry keys, punch card search and computer database program search (Wheeler & Baas 1998). Researchers have also tried to use DNA molecular marker technology (Yu et al 2017), near-infrared spectroscopy technology (Snel et al 2018), GC-MS technology (Wang et al 2018), computer vision technology (Hwang et al 2018) and other auxiliary identification methods to improve the accuracy of traditional methods in wood identification and speed the process of identifying wood species.…”

Wood discrimination analyses of Pterocarpus tinctorius and endangered Pterocarpus santalinus using DART-FTICR-MS coupled with multivariate statistics

“…Currently, the most frequently used method is traditional wood identification, which is based on macroscopic and microscopic anatomical features observed by seasoned experts. However, this method cannot identify wood samples at the species level (Jiao et al 2014;Hartvig et al 2015;Yu et al 2017;Jiao et al 2018). DNA barcoding has been rapidly developed and proven to be effective in wood identification even for dried wood (Jiao et al 2012) or heated or aged wood (Jiao et al 2014).…”