Evaluating the feasibility of using candidate DNA barcodes in discriminating species of the large Asteraceae family 

Ting Gao, Hui Yao, Jingyuan Song, Yingjie Zhu, Chang Liu, Shilin Chen

Abstract

BACKGROUND:Five DNA regions, namely, rbcL, matK, ITS, ITS2, and psbA-trnH, have been recommended as primary DNA barcodes for plants. Studies evaluating these regions for species identification in the large plant taxon, which includes a large number of closely related species, have rarely been reported.

RESULTS:The feasibility of using the five proposed DNA regions was tested for discriminating plant species within Asteraceae, the largest family of flowering plants. Among these markers, ITS2 was the most useful in terms of universality, sequence variation, and identification capability in theAsteraceae family. The species discriminating power of ITS2 was also explored in a large pool of 3,490 Asteraceae sequences that represent 2,315species belonging to 494 different genera. The result shows that ITS2 correctly identified 76.4% and 97.4% of plant samples at the species and genus levels, respectively. In addition, ITS2 displayed a variable ability to discriminate related species within different genera.

CONCLUSIONS:ITS2 is the best DNA barcode for the Asteraceae family. This approach significantly broadens the application of DNA barcoding to resolve classification problems in the family Asteraceae at the genera and species levels.

BMC Evol Biol. 2010 Oct 26;10:324. doi: 10.1186/1471-2148-10-324.