Testing three proposed DNA barcodes for the wood identification of Dalbergia odorifera T. Chen and Dalbergia tonkinensis Prain

Abstract

Abstract Dalbergia odorifera T. Chen is a first-grade state protected plant in China. However, it is difficult to distinguish it from the closely related species Dalbergia tonkinensis Prain, which is less important in economic value, by wood anatomical features. In this study, three potential DNA barcode sequences, namely rpoC1, trnH-psbA and internal transcribed spacer (ITS), were used to differentiate wood of D. odorifera from D. tonkinensis. The average quantities of DNA extracts from twigs, sapwood and heartwood were 16.3, 11.5 and 6.0 ng mg-1, respectively. The success rates for polymerase chain reaction (PCR) amplification for three loci, namely ITS, trnH-psbA and rpoC1, were 62.5, 100 and 81.25%, respectively. The success rate for bidirectional sequencing of amplified products was 100% for all the three loci. The identification power of the three proposed DNA barcodes has been calculated by the BLAST, tree-based method and the TAXONDNA method. The interspecific differences of the trnH-psbA region were greater than intraspecific variations. Moreover, the identification power of trnH-psbA was higher than that of ITS and rpoC1 regions at the species level. Finally, the trnH-psbA region is proposed as a DNA barcode for wood identification between D. odorifera and D. tonkinensis.