[Molecular authentication of Dendrobium chrysanthum from its allied species of Dendrobium].

OBJECTIVE: To define molecular characters to distinguish D. chrysanthum from its allied species D. primulinum, D. lituiflorum, D. aphyllum, D. crepidatum. METHOD: The molecular characteristics of D. chrysanthum and its allied species were compared. The sequences of rDNA ITS regions were exploited to explore the evidence for authentication D. chrysanthum and its allied species. RESULT: Although the morphological difference was slight, the sequence difference of ITS regions among five rDNAs was obvious and stable. Fifteen sites of ITS region were defined as DNA character to identify D. chrysanthum from the other four allied species. CONCLUSION: The difference of rDNA ITS sequences can be used to authenticate accurately D. chrysanthum from three allied species of Dendrobium.

[Database establishment of the whole rDNA ITS region of Dendrobium species of "fengdou" and authentication by analysis of their sequences].

AIM: To establish the whole rDNA ITS region sequence database of various Dendrobium species of "Fengdou" and to authenticate exactly the inspected species of "Fengdou". METHODS: The rDNA ITS regions of various Dendrobium species of "Fengdou" were amplified and sequenced. The database of their rDNA ITS regions was established in order to authenticate the inspected species by means of the softwares of CLUSTRAL and MEGA which were used to analyze the rDNA ITS region. RESULTS: A database of the rDNA ITS sequences of 21 species of Dendrobium has been established. The notable and stable differences of the interspecies of the rDNA ITS regions have been demonstrated. The numbers of transitions and transversions among 21 species are 11-122. The variable sites are 341 while the informative sites are 195. The ITS sequence differences between the outgroup species (Pholidota yunnanensis) and species of "Fengdou" are obvious. The numbers of transitions and transversions are 131-161. The population differences of the rDNA ITS region of various species of "Fengdou" are very small (0-6). CONCLUSION: On the basis of the database of various Dendrobium species of "Fengdou" and two genetics software, the botanical origin of the inspected species of "Fengdou" has been authenticated successfully by sequencing the rDNA ITS regions.