DNA barcoding of important fruit tree species of agronomic interest in the genus Garcinia L. from the Western Ghats

Abstract

Garcinia L. is a pantropically distributed genus with high species richness in South East Asia. It is a tropical evergreen plant with distinct morphological characteristics and has a high degree of endemism. Outstanding features of the Garcinia L. genus are monopodial growth, leafy texture, oil cavities containing yellow or light-colored resins present on all parts of the plant and polygamodioecious reproductive behavior. The current study was conducted to develop barcodes for different species of the genus Garcinia L., distributed widely in the Western Ghats of India. We assess the discrimination power of the plant DNA barcode (rbcL, matK, trnH-psbA, rpoB-trnCGAR and ITS), across major Garcinia L. species. Our results clearly demonstrate the value of plastid barcode data, previously unavailable for Garcinia L. species. Ten Garcinia L. species and three outgroup taxa selected from the Western Ghats of India for evaluation using four regions in the plastid genome (rbcL matK, trnH-psbA, rpoB-trnCGAR) and nuclear-transcribed spacer (nrITS) in order to discriminate them at the species level. A characteristic feature of all barcodes, maximum likelihood analysis, and Wilcoxon signed-rank test were used for species discrimination. The number of conserved sites were more using matK primer whereas more variables and informative sites found in rpoB-trnCGAR loci. For internal branches of species-specific clusters, maximum likelihood analysis showed a more resolved topology. Wilcoxon signed-rank test indicated a higher divergence for coding and non-coding regions. DNA barcoding was found to be a practical and rapid method for identifying more endemic species. These findings will potentially be helpful in delineating the various species of Garcinia L.