Applying plant DNA barcodes to identify species of Parnassia (Parnassiaceae)

Authors

  • JUN-BO YANG,

    1. Key Laboratory of Biodiversity and Biogeography, and Germplasm Bank of Wild Species in Southwest China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
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    • These authors contributed equally to this work.

  • YI-PING WANG,

    1. Jiangxi Agricultural University, Nanchang 330045, China
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    • These authors contributed equally to this work.

  • MICHAEL MÖLLER,

    1. Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh EH3 5LR, Scotland, UK
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  • LIAN-MING GAO,

    1. Key Laboratory of Biodiversity and Biogeography, and Germplasm Bank of Wild Species in Southwest China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
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  • DING WU

    1. Jiangxi Agricultural University, Nanchang 330045, China
    2. Jingdezhen College, Jingdezhen 333000, China
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Lian-Ming Gao, Fax: 86-871-5217791; E-mail: gaolm@mail.kib.ac.cn
Ding Wu, Fax: 86-798-8386194; E-mail: parnassia@sohu.com

Abstract

DNA barcoding is a technique to identify species by using standardized DNA sequences. In this study, a total of 105 samples, representing 30 Parnassia species, were collected to test the effectiveness of four proposed DNA barcodes (rbcL, matK, trnH-psbA and ITS) for species identification. Our results demonstrated that all four candidate DNA markers have a maximum level of primer universality and sequencing success. As a single DNA marker, the ITS region provided the highest species resolution with 86.7%, followed by trnH-psbA with 73.3%. The combination of the core barcode regions, matK+rbcL, gave the lowest species identification success (63.3%) among any combination of multiple markers and was found unsuitable as DNA barcode for Parnassia. The combination of ITS+trnH-psbA achieved the highest species discrimination with 90.0% resolution (27 of 30 sampled species), equal to the four-marker combination and higher than any two or three marker combination including rbcL or matK. Therefore, matK and rbcL should not be used as DNA barcodes for the species identification of Parnassia. Based on the overall performance, the combination of ITS+trnH-psbA is proposed as the most suitable DNA barcode for identifying Parnassia species. DNA barcoding is a useful technique and provides a reliable and effective mean for the discrimination of Parnassia species, and in combination with morphology-based taxonomy, will be a robust approach for tackling taxonomically complex groups. In the light of our findings, we found among the three species not identified a possible cryptic speciation event in Parnassia.

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