DNA barcoding of East Asian Amentotaxus (Taxaceae): Potential new species and implications for conservation

DNAbarcoding is a useful tool for species identification using standardized genomic DNA fragments. The genusAmentotaxus, consisting offive or six species, is confined to South China, Northeast India, Laos, and Vietnam. All species have been assessed as globally or nationally threatened. However, there is uncertainty about the number of species involved, especially in the border areas of southern China, northern Vietnam, and Laos. We selectedfive DNA barcodes (rbcL,matK,trnH-psbA,trnL-F, and internal transcribed spacer (ITS)) to evaluate their discrimination ability in this genus, and to investigate the current taxonomy ofAmentotaxus. Our results indicate that all the selected barcoding regions showed a high level of universality for PCR and sequencing. When six species are recognized, thenuclear ribosomal DNA region ITS and the chloroplast DNA regiontrnL-Fusedon their ownprovided the highest identification success (60%). Two barcode combinations that included either ITS ortrnL-Fhad the same species discrimination ability. Combinations using additional barcodes did not improve the species identification success. When only five species are recognized, withA. hatuyenensisT. H. Nguyen treated as a synonym of A. yunnanensisH. L. Li, the discrimination rate rises to 100%. Our results also indicate that recent collections from Yunnan province, China, Lao Cai province, Vietnam, and Laos may represent a potential new species. Thefindings from this study will be very useful for the formulation of appropriate conservation strategies for threatened Amentotaxusspecies in national and trans-boundary regions.
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