Genetic Identification of Cinnamomum Species Based on Partial Internal Transcribed Spacer 2 of Ribosomal DNA
SHIH-CHIEH LEE1*, CHANG-HUI LEE2, MIN-YI LIN2 AND KUEN-YIH HO3
1. Department of Bioindustry Technology, Da-Yeh University, Changhua 51591, Taiwan, R.O.C.
2. Department of Forestry and Nature Conservation, Chinese Culture University, Taipei 11114, Taiwan, R.O.C.
3. Department of Forestry and Nature Resources, National Chiayi University, Chiayi 60004, Taiwan, R.O.C.
(Received: November 15, 2009; Accepted: March 16, 2010)
ABSTRACT
The present study investigates the genetic identification of Cinnamomum species by analyzing the nucleotide sequences of the partial non-coding internal transcribed spacer 2 (ITS2) of ribosomal genes. The genetic diversity of the five Cinnamomum species (Cinnamomum cassia, C. zeylanicum, C. loureiroi, C. osmophloeum and C. burmannii) was studied using polymerase chain reaction (PCR) amplification and a DNA sequencing method to molecularly identify the tested specimens. Phylogenetic trees were constructed using several clustering methods, including unweighted pair-group method with arithmetic average (UPGMA), neighbor-joining (NJ) and maximum evolution (ME). The eleven test samples were clustered into three major groups based on partial ITS2 sequences. The phylogenetic results showed that C. osmophloeum and C. burmanii are phylogenetically related to each other and that both are more closely related to C. cassia. Based on our results, there is enough sequence variation within the sequenced ITS2 regions to identify individual specimens among the five tested Cinnamomum species. Therefore, these ITS2 regions could be adopted as a molecular marker for differentiating among C. cassia, C. zeylanicum, C. loureiroi, C. osmophloem and C. burmannii.
Key words: Cinnamomum spp., molecular identification, internal transcribed spacer2 (ITS2), phylogenesis