Identification of market adulterants in East Indian sandalwood using DNA barcoding

Abstract

East Indian sandalwood (Santalum album L.) in commercial markets is highly prone to adulteration. A number of cases were registered with regard to the adulteration of East Indian sandalwood, but the lack of technical tools for the precise species identification of the source wood stalled most of the court cases. The standard DNA barcode regions, the rbcL, matK and trnH-psbA chloroplast genomic sequences recommended by the Consortium of Barcode of Life (COBOL) were analysed to distinguish wood adulterants of East Indian sandalwood. Standard polymerase chain reactions with COBOL recommended primers were performed for all three barcode loci. The PCR products after gel elution were sequenced and alignments were performed using CLUSTALX. Single nucleotide polymorphisms (SNPs) identified with rbcL and trnH-psbA sequences of Erythroxylum monogynum Roxb. as well as with matK sequences of Osyris wightiana Wall ex. Wight could be efficiently utilized for the detection/monitoring of East Indian sandalwood adulterants. Among the two common adulterants O. wightiana and E. monogynum, the former was more similar to S. album and grouped together in the dendrogram. The study recommends the exploitation of DNA barcoding technique using standard barcodes to trace sandalwood timber adulterants.