DNA barcode chosen for identifying the world's plants

New identification technique could aid plant conservation<em> - News release</em>

Adapted from a press release issued by the Royal Botanic Garden Edinburgh
Tuesday 28 July 2009

A biologist from Imperial College London is part of an international team of 52 scientists that has concluded a four–year effort to agree on a standard 'plant DNA barcode', which will provide the foundation for the widespread use of DNA technologies to identify plants.

DNA barcoding, the use of a short standardised region of DNA for identifying species, has been used successfully to distinguish among animal species since 2003. A barcode library of approximately 60,000 animal species has been amassed already, based on the standard region selected in 2003. However, botanical barcoding has been more challenging. Although numerous strategies have been proposed, finding the right stretch of plant DNA has been difficult. Until now, no consensus has emerged among research groups as to which DNA region, or indeed how many regions, to use.

For the first time, the botanists involved in evaluating plant barcoding regions have pooled their data to agree on a standardised approach. This involved comparing the performance of the seven leading candidate DNA barcoding regions on a common set of samples. As a result of this research, two regions of DNA have been chosen to form the plant barcode - portions of the genes rbcL and matK.

The plant DNA 'barcode' will enable researchers asses the diversity of species in the world's biodiversity hotspots

The technique will work on minute amounts of tissue and can be used on fragments of plant material. Applications include identifying illegal trade in endangered species, identifying invasive organisms, poisonous species and fragmentary material in forensic investigations. But, potentially, the main application will be assessment of the diversity of species in the world's biodiversity hotspots where a shortage of specialist skills hampers conservation efforts.

Professor Vincent Savolainen from Imperial's Department of Life Sciences commented: "It's fantastic that the botanical community got together to identify this universal 2-gene barcode. It builds on our previous work with the matK gene for the flora of South Africa, and with colleagues in Africa we are now working towards DNA barcoding all African tree species to help conservation and biodiversity science programmes."

Dr Peter Hollingsworth, Head of Genetics and Conservation at the Royal Botanic Garden Edinburgh, who has chaired the group, explained: "Identification is important - it is the link between a given plant and the accumulated information available for that species. It is not possible to know if a plant is common or rare, poisonous or edible, being traded legally or illegally, unless it can be identified. Conservation prioritisation, in particular, can be impeded by a lack of knowledge of what species grow where. But identifications can be difficult: there are a large number of plant species and some look very similar. Juvenile, non-flowering or fragmentary materials are notoriously difficult to identify."

DNA barcoding is one way round the problem – the principle of the approach is to identify a stretch of DNA which is suitable for telling most species apart and to use this to build a massive and easily accessible database to provide a universal system for identifying the world’s biodiversity.

Dr David Schindel, Executive Secretary of Washington DC based Consortium for the Barcode of Life (CBOL) which instigated the formation of the plant working group, commented: "The selection of standard barcode regions has been a slow and difficult process because of the complex nature of plant genetics. Dr Hollingsworth and the Plant Working Group are to be congratulated for the careful and collaborative way in which they have approached their difficult task. Having an agreed upon barcode region will enable plant barcoding to accelerate rapidly. There are researchers around the world and diverse users of plant identification who are eager to get started."

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