Skip to main content

How to ID plants through DNA barcoding

It’s not just humans and animals that have DNA in their cells, plants and fungi do too.

In fact, DNA barcoding can be used to identify plants, detect invasive species and help conservation work, as our Senior Ecological Advisor Sarah Shuttleworth explains.

Photo shows a number of clear test tubes resting in a yellow tray. There is a plant in a vase behind the test tubes.

Like all living organisms, plants and fungi have DNA (deoxyribonucleic acid) in their cells. DNA is the genetic code, which is the blueprint for genes, which gives an organism its specific characteristics. Different species will have a different DNA blueprint (with small variations within that as well) and these can help us tell species apart and see which ones are closely related.

I was recently offered a place on an exciting course to learn all about DNA barcoding and how it can help my work as a botanist.

Sarah Shuttleworth at DNA barcoding course

So, what is a DNA barcode?

Put simply, we can compare different DNA blueprints by comparing just a small section of the DNA sequence. This small section is referred to as the DNA barcode. There is a reference library which contains information about many species with their corresponding barcode.

In order to compare DNA barcodes of different species, the shortened sequence (region) needs to be the same region of the comparison species. However, which region you select to shorten and use for comparison is different depending on which type of organism you have. For example, all organisms within the animal kingdom are identified using the same specific DNA region, whilst all plants are identified using a different region.

 

The DNA region used for barcoding differs between kingdoms:

  • In fungi, the most commonly used DNA barcode is the internal transcribed spacer (ITS) region. This is the specific part of the DNA sequence used for fungi.
  • There are several candidates for DNA barcoding in plants. The two gene targets recommended are maturase K (matK) and ribulose bisphosphate carboxylase (rbcL).

DNA barcoding relies on a region of DNA that varies significantly between different species to allow the different species to be identified.

Attendees at DNA barcoding course

How do you extract the DNA and barcode it?

First, we need to collect a tiny bit of plant and/or fungi samples for our study. We don’t need much, just a small amount to get the DNA. To get the DNA out, we cut really tiny pieces from the samples. Then, we put these pieces in a tube with a special liquid solution and smush them with a small tool to break the cells apart and release the DNA.

Next, we need to make lots of copies of the DNA which we do by using a special mix of certain chemicals (there are different special mixes for plants and fungi).

To check if we’ve done it right, we use a method called gel electrophoresis. This method is used to separate mixtures of DNA, RNA, or proteins to molecular size (you will see a nice clear line in the gel if it has been successful.) This helps us see if the DNA we extracted is good and whether we can send it to the lab. The lab will then send us the DNA sequence so it can be compared it to other sequences in a big database.

How can DNA barcoding help with plant conservation?

Using these DNA barcoding skills can help us in many ways, including identifying single species or a community of species.

  • Single species barcoding – is when you collect a sample from a plant, fungus or animal, extract DNA from the sample, amplify the DNA barcode and send the DNA barcode for sequencing. This can help us record species accurately and identify species we have on our reserves that are difficult to identify. (The International Barcode of Life (iBOL) project seeks to make DNA barcoding globally accessible for the discovery and identification of all multicellular life on Earth.)
  • Community barcoding or metabarcoding – is when a sample contains a mixture of species, so DNA is extracted, amplified and sequenced from all the species in the mix that are targeted by the DNA barcode used. An example of metabarcoding is identifying the fungal diversity in a soil sample.
  • Detection of invasive species – DNA sampled from the environment (eDNA) can be barcoded to monitor the presence of invasive species of concern.

It is quite a technical process but as local groups (mainly fungi recording organisations) are starting to invest in the kit, more people should be able to get involved in DNA barcoding.

Sarah Shuttleworth on a DNA barcoding course

I hadn’t had a chance to do anything like this since my first year at university and I was surprised about how much came flooding back to me. The course was a great opportunity to learn and refresh my skills, as well as meet other people with an interest in species identification and conservation.

After more practicing, we hope to use these skills to add to the genomic database and assist our own species recording accuracy.

In the future, perhaps Plantlife can utilise these skill sets for looking at species assemblages on our reserves or places we are hoping to maximise conservation efforts.

Volunteer biological recording group RoAM (Recorders of the Avalon Marshes) at Somerset Wetlands NNR (National Nature Reserve) organised the DNA barcoding course with funding from Natural England through the Natural Capital and Ecosystem Assessment Programme. I was offered a spot on this exciting course due to my work and contacts in a voluntary capacity with the North Somerset and Bristol Fungi Group.

Natural England: EDNA (Environmental DNA) approaches to environmental monitoring are incredibly valuable to Natural England’s work, but recognise their limitations, not least that some groups of fungi, lichen and invertebrates are poorly represented in genomic databases. By helping to train our highly skilled taxonomic recorders with DNA barcoding means better records and more effective eDNA outputs.

 

  • Go to:
Several purple Early Marsh Orchids in the grassland

What are orchids? 

Orchids are part of the largest and most highly evolved family of flowering plants on earth. They are usually highly specialised to a specific habitat, with equally specialised relationships with pollinators, and fungi which live in the soil. 

What makes them so rare?

The majority of species reproduce via tiny seeds that are known as ‘dust seeds’ which need perfect conditions to germinate – with some species even relying on specific types of fungi in the soil for them to grow. This means that conditions in the soil and habitat need to be exactly right for an orchid species to thrive, hence why we don’t encounter them all the time. 

One UK orchid has gained huge notoriety for its rarity, the Ghost Orchid Epipogium aphyllum. This species is currently regarded as extinct but with hopes for its re-discovery. Occurring in Beech woodlands in deep leaf litter where gets its energy from decaying matter, it’s appropriately named for its pinkish white ghostly appearance rising from dead leaves.   

Where can you find orchids in the UK?

Although orchids are not the most common plant you will find, they do occur in a huge variety of habitats. Traditional hay meadows and pastures can host several species, the most common of these are

  • Common Spotted Dactylorhiza fuchsii
  • Marsh Orchids Dactylorhiza sp
  • Bee Orchid Ophrys apifera and
  • Common Twayblade Listera ovata

Many orchids also specialise in woodlands, for example Early Purple Orchid Orchis mascula, Helleborines Epipactus sp and Bird’s-nest Orchid Neottia nidus-avis (pictured), a fascinating yellow orchid without any chlorophyll that depends entirely on getting its food from decaying material in the leaf litter. There are also species that grow in fens and bogs, pine forests, heathlands and dunes.  

The majority of the time due to the specific requirements for growth, orchids tend to be associated with long established habitats, that haven’t had lots of disturbance. Therefore, a nature reserve can often be a useful place to look.  

How to spot orchids in the wild?

The best time of year to look for orchids tends to be late spring and early summer. Quite a few UK orchids have spotted leaves, making them even more distinctive and easy to spot. 

They are perennial plants, and in the UK are formed of a spike of flowers on a single stem. They all share a similar flower structure, despite the huge variety in their appearance. There are 3 sepals (outer protective petal-like parts) and 3 main petals, with one that usually forms a lower lip known as the labellum. This lip is often the largest and most distinctive ‘petal’ structure of the flower. 

Often their intricate design and some species astonishing mimicry to tempt pollinators is one of the most intriguing features of these plants. With Bee and Fly Orchids imitating these insects to attract them to land on the flower, mistaking them for a potential mate, and thereby pollinating the flower. 

How to tell them apart?

The key features of orchids for identification other than habitat, are the leaves (shape and markings) and the lower lip of the flower (labellum). The easiest species to start with are Early Purple Orchid, Common Spotted Orchid, Bee Orchid and Common Twayblade. This is because they are relatively more common than other species and most can occur in grassland and woodland habitats. 

It is always exciting to find any kind of orchid, and worthy of a photo! Just remember to be careful not to tread on any nearby orchids that are just coming up. Share the photos with friends, as you never known who doesn’t know that our wonderful UK orchid species even exist.  

Further reading 

FSC Orchid Guide

The Orchid Hunter by Leif Bersweden  

Britain’s Orchids A Field Guide to the Orchids of Great Britain and Ireland by Sean Cole, Michael Waller and Sarah Stribbling  

How to Find Fungi
Shaggy Inkcaps

How to Find Fungi

Getting out and looking for fungi can be a great way to connect with nature and discover more about this amazing kingdom. Here our Specialist Botanical Advisor, Sarah Shuttleworth, gives her top tips for finding fungi! 

How many fungus species are there?
Fly Agaric

How many fungus species are there?

Recent studies have revealed that there's so much fungi out there that we don't know about. But how do we know this? Rachel Inhester, from our science team, tells us why.

Plants to Spot at the Seaside this Summer
Photo looks out over the cliffs to the sea and shows in the foreground, pink Sea Thrift and purple Heather clinging to the rocky cliffs.

Plants to Spot at the Seaside this Summer

Sun, sand, sea and wildflowers – why not add finding flowers to your list of beach time activities this summer.