PLOS ONE：版纳植物园建立热带森林树种DNA条形码数据库

摘要 : 随着全球气候变化的影响及人类活动的加剧，特别是热带经济作物如橡胶等的大面积种植，西双版纳作为我国生物多样性最丰富的地区之一，目前面临严重的威胁。DNA条形码能够利用一小段DNA序列快速进行物种鉴定，为生物多样性保护提供了一个极为有效的可靠途径。该项目受到科技部科技基础性工作专项(2012FY110400)的资助。

随着全球气候变化的影响及人类活动的加剧，特别是热带经济作物如橡胶等的大面积种植，西双版纳作为我国生物多样性最丰富的地区之一，目前面临严重的威胁。DNA条形码能够利用一小段DNA序列快速进行物种鉴定，为生物多样性保护提供了一个极为有效的可靠途径。该项目受到科技部科技基础性工作专项(2012FY110400)的资助。

中国科学院西双版纳热带植物园植物系统发育与保护生物学研究组从2008年起，对西双版纳国家级自然保护区内不同植被类型的热带森林开展了区域DNA条形码研究。从隶属于76科、259属、655树种的2052个个体中获得了rbcL、matK、trnH-psbA和ITS四个DNA条形码片段的5583条序列;利用BLAST方法，结合传统形态学观察及专家鉴定，发现并纠正了野外鉴定错误的99个个体。此外，研究发现作为国际植物DNA条形码联盟推荐的标准条形码的rbcL和matK，对西双版纳热带森林乔木树种的鉴别能力有限，而补充条码ITS虽然受到测序成功率不高的限制，但其树种鉴别能力最高，进而建议将其与trnH-psbA联合共同列为西双版纳地区热带森林树种的DNA条形码;与世界其它热带地区相比，西双版纳地区DNA条形码的树种鉴别能力较低，推测可能与物种组成及共存种之间的差异有关。

该项研究首次建立了我国热带森林树种的DNA条形码数据库，为生物多样性的大尺度调查提供了有力的工具，促进了系统发育群落生态学等相关学科的快速发展;同时，为进一步对该地区开展系统发育多样性的评估和自然保护区合理有效的规划，以及珍稀濒危物种的保护提供了可能，为群落系统发育进化树的构建和外来入侵种的快速鉴定提供了重要的基础数据。

研究成果以Application of DNA Barcodes in Asian Tropical Trees – A Case Study from Xishuangbanna Nature Reserve, Southwest China 为题发表在PLoS ONE上。

原文链接：

Application of DNA Barcodes in Asian Tropical Trees – A Case Study from Xishuangbanna Nature Reserve, Southwest China

原文摘要：

Background

Within a regional floristic context, DNA barcoding is more useful to manage plant diversity inventories on a large scale and develop valuable conservation strategies. However, there are no DNA barcode studies from tropical areas of China, which represents one of the biodiversity hotspots around the world.

Methodology and Principal Findings

A DNA barcoding database of an Asian tropical trees with high diversity was established at Xishuangbanna Nature Reserve, Yunnan, southwest China using rbcL and matK as standard barcodes, as well as trnH–psbA and ITS as supplementary barcodes. The performance of tree species identification success was assessed using 2,052 accessions from four plots belonging to two vegetation types in the region by three methods: Neighbor-Joining, Maximum-Likelihood and BLAST. We corrected morphological field identification errors (9.6%) for the three plots using rbcL and matK based on Neighbor-Joining tree. The best barcode region for PCR and sequencing was rbcL (97.6%, 90.8%), followed by trnH–psbA (93.6%, 85.6%), while matK and ITS obtained relative low PCR and sequencing success rates. However, ITS performed best for both species (44.6–58.1%) and genus (72.8–76.2%) identification. With trnH–psbA slightly less effective for species identification. The two standard barcode rbcL and matK gave poor results for species identification (24.7–28.5% and 31.6–35.3%). Compared with other studies from comparable tropical forests (e.g. Cameroon, the Amazon and India), the overall performance of the four barcodes for species identification was lower for the Xishuangbanna Nature Reserve, possibly because of species/genus ratios and species composition between these tropical areas.

Conclusions/Significance

Although the core barcodes rbcL and matK were not suitable for species identification of tropical trees from Xishuangbanna Nature Reserve, they could still help with identification at the family and genus level. Considering the relative sequence recovery and the species identification performance, we recommend the use of trnH–psbA and ITS in combination as the preferred barcodes for tropical tree species identification in China.

作者：西双版纳热带植物

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