Applicability of chloroplast DNA barcodes for wood identification between Santalum album and its adulterants

Abstract

The East Indian sandalwood, Santalum album L., is known for its fragrant heartwood and extractive oils. The increasing demand for the valuable sandalwood products has led to illegal and excessive logging, and there are other Santalum species in the commercial market as substitutes (adulterants). Improved tools for the identification of Santalum species are needed to control this situation. In this study, four chloroplast DNA (cpDNA) regions were screened (matK, psbA-trnH, trnK and trnL) on 35 vouchered specimens covering five Santalum species, i.e. Santalum acuminatum, S. album, Santalum lanceolatum, Santalum murrayanum and Santalum spicatum. The goal of this study was to test the species discrimination ability by means of both the TaxonDNA and neighbor-joining (NJ) methods. The results indicate that the combination of psbA-trnH+trnK gave the best performance for discrimination (100%) of the studied Santalum species concerning the discrimination ability and recovery rate. Meanwhile, six unvouchered wood specimens were retrieved and accurately identified at the species level based on the recommended DNA barcodes. The DNA barcode method is now ready for application in the monitoring of the trade of this valuable resource, and provides an effective approach for wood species identification and product authentication.