Unlocking Nature’s Secrets: Ancient Gene Found Behind Prickles On Roses

Roses, often associated with love and romance, are also notorious for their sharp spikes—prickles that emerge from their stems to deter animals from eating the buds. But roses aren’t the only plants with this defense mechanism. Other plants, such as spider flowers and brambles (which produce raspberries and blackberries), as well as crops like tomatoes, eggplants, barley, and rice, also feature these sharp points.

So how did these diverse species, which evolved separately over millions of years, come to share this trait? According to a new study published in Science on Thursday, the answer lies in their DNA. Researchers traced the origin of this feature to an ancient gene family responsible for prickles in all these plants.

The study not only sheds light on how to potentially develop prickle-free plant variants but also provides insights into the evolutionary history of a wide array of plants.

The Evolution of Prickles

Unlike thorns, which are the woody projections found on certain shrubs and trees, such as honey locusts and citrus trees, roses have prickles. These form from the plant’s skin, similar to how hair grows. Prickles have existed for at least 400 million years, emerging when ferns and their relatives first appeared. Over time, this trait has appeared and vanished in various evolutionary contexts, according to Zachary Lippman, a plant biologist and professor of genetics at Cold Spring Harbor Laboratory.

One of the most diverse plant genera, Solanum—which includes potatoes, tomatoes, and eggplants—developed prickles around 6 million years ago. Today, this genus contains over 1,000 species, with about 400 known for their prickles.

Prickles and thorns are evolved defenses against herbivores, helping with growth, plant competition, and water retention. The study reveals that prickles’ occurrence across various plant lineages is due to convergent evolution, where different species independently evolve similar traits in response to similar environmental pressures. Wings, for instance, evolved independently in birds, bats, and some squirrels.

The Role of Lonely Guy Genes

Researchers found that prickles in around 20 studied plant species, including roses and eggplants, are controlled by a gene family known as Lonely Guy, or LOG. These genes are present in all plants, even mosses, the earliest land plants. LOG genes regulate the hormone cytokinin, crucial for cellular functions like division and expansion, which affects plant growth.

“Our study shows that rather than a single common ancestor with prickles, this trait seems to have evolved independently in different lineages over millions of years,” Lippman said. “The question now is how often is convergent evolution not just about the traits we observe, but also about the genes responsible?”

Genetic Implications

This discovery provides new tools for studying prickle protection against herbivores. Previously, removing prickles from fully grown plants to test their impact was challenging and could harm the plant. Now, with the gene identified, scientists can use genome editing techniques like CRISPR to create prickle-free variants more efficiently, which can benefit agricultural practices by making harvesting easier and potentially introducing new produce to the market.

Vivian Irish, a plant biologist and Yale University professor, noted that understanding the role of LOG genes in prickle development helps us appreciate the evolutionary adaptability of plants. “LOG genes have been co-opted repeatedly in different species for prickles and lost in others where prickles are not needed,” she said. “This might reflect nature’s tendency to reuse old genes in new ways.”

This research opens up possibilities for more precise genetic modifications in plants, potentially leading to improved agricultural practices and better access to diverse types of produce.

(Includes inputs from online sources)

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