DNA barcoding of epiphytic orchids for species level identification.

DNA barcoding has proven to be an effective technique for molecular-level identification in plants, including orchids which exhibit a great degree of genetic variability but show almost identical morphological features in closely related genera. The present study was conducted to evaluate the effectiveness of universal chloroplast gene markers, matK (maturase K gene) and rbcL (ribulose-1, 5-bisphosphate carboxylase/oxygenase large subunit) as DNA barcodes to identify Aerides multiflora and Rhynchostylis retusa at species level. The DNA sequences from different genotypes of both the orchid species collected from natural populations were compared with database sequences of orchid species using BLAST and maximum likelihood phylogenetic tree. For A. multiflora samples, the phylogenetic analysis revealed a highest of 99.4% sequence percentage alignment (for matK region) and 99.39% percent identity with sequences belonging to A. multiflora accessions. In the case of R. retusa, the matK region showed a highest sequence percentage alignment of 99.87% with the accessions of R. retusa, while the highest per cent identity for the rbcL region was 100% that matched with accessions of R. retusa, C. peduncularis and A. praemorsa. The study confirms the reliability of matK and rbcL markers for authentication of the two orchid species under the current investigation. [ABSTRACT FROM AUTHOR]