Identification of plants in Euphorbiaceae in Hainan by ITS2 barcoding sequence / 中草药

ABSTRACT

Objective: To evaluate the ability of ITS2 region as a DNA barcode for identifying the plants in Euphorbiaceae in Hainan. Methods: The ITS2 of ribosomal DNA was amplified and sequenced by bidirectional sequencing of PCR products. Sequence assembly and consensus sequence generation were performed by using Codon Code Aligner. Phylogenetic study was performed using software MEGA 6.0 in accordance with Kimura-2-parameter (K2P) model, and the phylogenetic tree was constructed by using the Neighbor-joining (NJ) method. The ITS2 secondary structure was predicted using the ITS2 Database server. The distribution of intra-versus inter-specific variability was compared using DNA bar coding gaps. Results: The variable sites and the informative sites were accounted for 84% and 69.67% of the ITS2 regions length. In the cluster dendrogram, all species showed monophyletic. The maximum intra-specific distance was 0.067 3, and the minimum inter-specific distance was 0.119 1. There was significant bar coding gap between intra-specific and inter-specific variation. To compare the ITS2 secondary structure, we noticed that it had no obvious distinguishment of intra-specific, while had obvious distinguishment of inter-specific. Conclusion: ITS2 sequence can be used as a DNA barcode for the rapid identification of the plants in Euphorbiaceae in Hainan.