Identification of medicinal Dendrobium species by phylogenetic analyses using matK and rbcL sequences

Abstract

Species identification of five Dendrobium plants was conducted using phylogenetic analysis and the validity of the method was verified. Some Dendrobium plants (Orchidaceae) have been used as herbal medicines but the difficulty in identifying their botanical origin by traditional methods prevented their full modern utilization. Based on the emerging field of molecular systematics as a powerful classification tool, a phylogenetic analysis was conducted using sequences of two plastid genes, the maturase-coding gene (matK) and the large subunit of ribulose 1,5-bisphosphate carboxylase-coding gene (rbcL), as DNA barcodes for species identification of Dendrobium plants. We investigated five medicinal Dendrobium species, Dendrobium fimbriatum, D. moniliforme, D. nobile, D. pulchellum, and D. tosaense. The phylogenetic trees constructed from matK data successfully distinguished each species from each other. On the other hand, rbcL, as a single-locus barcode, offered less species discriminating power than matK, possibly due to its being present with little variation. When results using matK sequences of D. officinale that was deposited in the DNA database were combined, D. officinale and D. tosaense showed a close genetic relationship, which brought us closer to resolving the question of their taxonomic identity. Identification of the plant source as well as the uniformity of the chemical components is critical for the quality control of herbal medicines and it is important that the processed materials be validated. The methods presented here could be applied to the analysis of processed Dendrobium plants and be a promising tool for the identification of botanical origins of crude drugs.

DNA barcoding of arid wild plants using rbcL gene sequences

“…Tree analyses using rbcL sequences assigned 17% of the tested plant samples to known species. Our findings, notwithstanding rbcL is considered to possess less species-discriminating power than matK, are possibly due to its minimal sequence variation (Asahina et al, 2010). The estimated range of the total number of plant species worldwide is believed to be approximately 310,000-422,000 (Graham, 2002).…”

Identification of native Dendrobium species in Thailand by PCR-RFLP of rDNA-ITS and chloroplast DNA

“…The abbreviations of each species are described in Table 2. proaches. The sequences of rDNA-ITS and the sequences of matK and rbcL genes of cpDNA 13,15 have been used to provide species identification of some Dendrobium plants. The sequence-based procedure could be the basis of a reliable protocol for species identification and could provide taxonomic information for clarifying evolutionary relevance of the taxa studied 24,25 .…”

“…In Dendrobium, both the sequences of rDNA-ITS 13,14 and cpDNA 15 and the PCR-RFLP of cpDNA (rbcL gene) 16 were used for species identification and determination of their genetic relationship. Moreover, inter-simple sequence repeat (ISSR) marker was also used for species identification and phylogenetic relationship of 31 Dendrobium spp.…”

Identification of Dendrobium Species Used for Herbal Medicines Based on Ribosomal DNA Internal Transcribed Spacer Sequence

“…[16][17][18][19][20][21][22][23][24][25][26][27] Unfortunately, these methods have only been applied to a limited number of Dendrobium species, and molecular markers that can be applied more universally to Dendrobium have not been developed. To recognize herbal medicines accurately at the species level, a comprehensive DNA sequence database that covers Dendrobium species potentially used for medicine is desired, and to create such a database, the following conditions are required: (1) precise identification of the plant species, (2) comprehensive data banking of reference sequences for the relevant plant group at the species level, and (3) employment of sequence markers that can discriminate interspecific differences.…”