Phylogenetic Relationships of <i>Santalum album</i> and its Adulterants as Inferred from Nuclear DNA Sequences

Abstract

The East Indian sandalwood, <i>Santalum album,</i> valued for its fragrant oil yielding heartwood is a major ingredient in indigenous medicines and perfumes. Scarcity of sandal has led to illegal felling of sandal trees, and adulteration of sandalwood and oil. This study represents the first molecular phylogeny of <i>S. album</i> and its adulterant species <i>Osyris wightiana</i>, <i>Erythroxylum monogynum, Buxus sempervirens, Ximenia americana, Osyris lanceolata, </i>and <i>Chukrasia tabularis</i> through 18S and 26S rDNA sequencing. In the Maximum Parsimony (MP) tree for 18S and 26S rDNA data sets, moderate to high bootstrap support was obtained for the nodes. For 18S rDNA data sets, the tree had <i>B. sempervirens </i>and<i> X. Americana</i> as the upper branch, with <i>E. monogynum</i> branched separately to the cluster. The lower branch had <i>S. album </i>and<i> O. wightiana</i> with <i>O. lanceolata</i> joining separately to both clades of the tree. In the MP tree for 26S rDNA datasets, <i>S. album </i>and <i>O. wightiana</i> formed the major cluster with <i>X. americana</i> clustering separate and <i>B. sempervirens</i> and <i>O. wightiana </i>as the lower branch with<i> C. tabularis</i> clustering separate to the tree. The molecular data presented here provided useful information for resolving the phylogenetic relationship of these plants. Inferences from this study are in accordance with Cronquist’s system of classification of flowering plants where all the species originate from a single phylogenetic tree of Rosidae.