Botanists Agree On Plant DNA ‘Barcode’ For Identification

After four years of debate, an international team of scientists from 25 institutions has finally agreed on a standard “DNA barcode” for plants for quick and easy identification of species.

The team hopes that the agreement will allow for the eventual formation of a global plant DNA library, which can be shared by the scientific community.

The barcode is a short sequence of DNA unique to every species that could ultimately have a handheld plant “scanner” for quickly identifying species intercepted from illegal logging operations or to identify potentially toxic plants in an emergency situation.  

On top of that, it would greatly simplify the daily mundane task of identifying and studying new species.

The findings appear in the Proceedings of the National Academy of Sciences.

“Identification is important,” said lead author Dr Peter Hollingsworth, head of genetics and conservation at the Royal Botanic Garden, Edinburgh, Scotland.

“It is the link between a given plant and the accumulated information available for that species. It is not possible to know whether a plant is common or rare, poisonous or edible, being traded legally or illegally, unless it can be identified,” he said.

Co-author and conservation geneticist Robyn Cowan at Royal Botanic Gardens says that this development would mean that larger areas could be surveyed more quickly.

“We are short of botanists and their expertise in a lot of places around the world,” she told BBC News.

“This is one way that we will be able to increase our information and understanding of biodiversity and where things are growing around the world.”

She further explained that now samples could be sent back to laboratories for processing and identification, which would make having a specialist botanist on location totally unnecessary.
 
According to Cowan, the new method would help to quickly instate conservation measures in order to save endangered species.
 
“And there are also more applied uses; in forensics, for example,” she said.

“We have also done a little bit of preliminary work on Chinese herbal medicines. We have been checking that people are getting what they should be getting in terms of medication and active ingredients.

“One thing that is really good about this process is that you can identify plants from different life stages or just fragments of plants. For example, if you are looking at trade in endangered species and you have things that are not flowering, or are just seedlings, it can be incredibly difficult to positively identify the plants.”

Cowan delineated why agreeing on a DNA barcode for plants proved to be more difficult than finding one for animals, which has been used since 2003.

“The DNA in land plants behaves, in some ways, quite differently to DNA in animals, so we were not able to use the same [marker],” she explained.

“We had to search for the best solution because a barcode needs certain characteristics”¦it needs to be technologically easy to deal with; it needs to be readily obtainable from degraded material (very old samples or fragments); and it needs to be variable enough between species to be able to separate them but not too variable within species.”

After assessing seven potential “barcodes” by testing them on a common set of samples, they finally chose two regions of DNA to form the plant barcode.
 
“The conclusion we have come to will give us a good basic barcode to use.”

There were 52 scientists from 10 nations in the Consortium for the Barcode of Life (CBOL) Plant Working Group that took part in the four-year process.
 
Executive secretary of CBOL David Schindel praised the breakthrough in saying, “The selection of standard barcode regions has been a slow and difficult process because of the complex nature of plant genetics.”

He added that the development would “enable plant bar-coding to accelerate rapidly”.

One use will be to build a DNA database for the 100,000 tree species in the world. Many of them are considered to be of either conservational or economic importance.

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