Format: ORAL

Feng Song1, Ting Li 1, Hai-Fei Yan1, Ying Feng2, Lu Jin1, Kevin S. Burgess3, Xue-Jun Ge1

1. Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China 2. State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China 3. Department of Biology, Columbus State University, University System of Georgia, Columbus, USA

DNA barcoding is a well-established tool for rapid species identification and biodiversity monitoring. A reliable and traceable DNA barcode reference library with extensive coverage is necessary but unavailable for many geographical regions. Thearid region in northwestern China, with a vast area of about 2.5million km2 , is ecologicallyfragile and often overlooked in biodiversity studies. In particular, DNA barcode datafrom the arid region of China is lacking. We develop and evaluate the efficacy ofan extensive DNA barcode library for native flowering plants in the arid region ofnorthwestern China. Plant specimens were collected, identified and vouchered forthis purpose. The database utilized four DNA barcode markers, namely rbcL, matK,ITS and ITS2, for 1816 accessions (representing 890 species from 385 genera and 72families), and consisted of 5196 barcode sequences. Individual barcodes varied in resolution rates: species- and genus-level rates forrbcL, matK, ITS and ITS2 were 79.9%51.1%/76.1%, 79.9%67.2%/88.9%, 85.0%72.0%/88.2% and 81.0%67.4%/84.9%,respectively. The three-barcode combination of rbcL+matK+ITS (RMI) revealed ahigher species- and genus-level resolution (75.5%/92.1%, respectively). A total of 110plastomes were newly generated as super-barcodes to increase species resolution forseven species-rich genera, namely Astragalus, Caragana, Lactuca, Lappula, Lepidium,Silene and Zygophyllum. Plastomes revealed higher species resolution compared tostandard DNA barcodes and their combination. We suggest future databases includesuper-barcodes, especially for species-rich and complex genera. The plant DNA barcode library in the current study provides a valuable resource for future biologicalinvestigations in the arid regions of China.