Thanks to international expertise in plant sciences, researchers have found that all plants with prickles share the same gene, despite having diverged from a common ancestor over 150 million years ago.

In a paper published on August 2, 2024, in the journal Science, researchers at Royal Botanic Garden Edinburgh and partners show that by removing that gene, prickles, often known colloquially as thorns or spines, could now be eliminated from species such as cultivated roses and agricultural crops, with no impact on taste, look or smell. The knowledge could make it easier and cheaper to harvest crops, with clear benefits for agriculture, particularly in developing countries.

Dr Tiina Sarkinen, a Tropical Biodiversity Scientist specialising in the Solanaceae family at RBGE, was part of the international research team and used evolutionary mapping to identify some surprising new findings. She explained:

“One of the great, enduring mysteries of evolution is how different types of plants, growing in wildly different environments, can share the same characteristics. Prickles are a great example of this, but we didn’t know how or why they evolved.

“By examining the evolutionary relationship between 740 species of Solanum – the plant genus that includes potatoes, tomatoes and aubergines – we discovered that, over many millennia to up to millions of years, 14 species had lost their prickles. This knowledge helped us to narrow down and identify the one gene that controls prickles in Solanum.

“We then applied that finding to as many other plant species with prickles and were astonished to discover that they all shared the same gene. It turns out that prickles are deceptively simple – and this knowledge will have many benefits for agriculture.”

Using these findings, researchers have been successfully able to remove prickles from species as diverse as the gboma eggplant (Solanum macrocarpon), a domesticated aubergine native to Africa and the desert raisin (Solanum centrale), a plant foraged for thousands of years by indigenous people in Australia. The same techniques should also allow horticulturists to develop more thornless roses.

In botanical terms, prickles are derived from a plant’s epidermis and are a key evolutionary tool, helping them to deter predators such as herbivores, climb or survive drought. They evolved at least 28 times over more than 400 million years of evolution in many plant families.