Genetic Diversity and Relationship of Native Phalaenopsis Orchids: A Case Study of Indonesian Archipelago

Abstract

The native Phalaenopsis is valuable germplasm for future orchid breeding programs and for its conservation because it provides many beneficial traits or genes. This study aimed to determine and analyze the molecular diversity and phylogeny of Indonesian native Phalaenopsis by a DNA barcoding (matK) marker. A total of 19 samples of Phalaenopsis orchids were used in this study. All leaf samples of orchid were extracted and purified using a commercial DNA isolation kit from Geneaid Biotech Ltd., Taiwan (GP100). The DNAs were then amplified by specific matK primers: Forward (5’-CGTACAGTACTTTTGTGTTTACGAG-3’) and Reverse (5’-ACCCAGTCCATCTGGAAATCTTGGTTC-3’). The DNA targets or products (matK) were purified and sequenced by the Sanger-bidirectional method at 1st Base Ltd., Malaysia. Before further analysis, the matK sequences of Phalaenopsis were edited, reconstructed, and aligned with the assistance of Clustal W in the MEGA 11 software. Its genetic diversity was determined using the nucleotide diversity index (π%), and the phylogenetic analysis was performed using the maximum likelihood (ML) method with a statistical bootstrap. The phylogenetic relationship was also assessed using principal component analysis (PCA). Based on this marker, the native Phalaenopsis has a high genetic diversity (π% = 1.70). In addition, the phylogenetic analysis revealed that this germplasm was separated into seven clades, where P. pantherina has the closest relation to P. cornu-cervi and P. gigantea. Conversely, the highest genetic distance was to P. amabilis from South Kalimantan and to P. celebensis from Sulawesi, at a coefficient divergence of 0.084. Our findings provide an essential foundation for supporting future orchid breeding practices, including conservation, on local and global scales.