Scientists Trace the Origins of Roses’ Thorns and Uncover a 400-Million-Year-Old Evolutionary Mystery

Introduction: Unraveling the Mystery of Prickles

Roses, known not only for their romantic symbolism but also for their sharp, protective spikes, have long intrigued botanists and nature enthusiasts alike.

These prickles, which protrude from the stems of roses, serve a crucial defensive role by deterring animals that might otherwise consume the buds.

However, roses are not unique in their use of this defensive mechanism.

Many other plants, from spider flowers and brambles to crops like tomatoes and eggplants, also exhibit these sharp structures.

The fascinating question that arises is: How did this spiny feature evolve independently in so many diverse plant species over millions of years?

Recent research sheds light on this intriguing question.

A team of international scientists has traced the origins of these prickles to a single ancient gene family, revealing that a common genetic ancestry underlies the presence of prickles across various plant species.

This groundbreaking study, published in the journal Science, not only enhances our understanding of plant evolution but also opens up new possibilities for agricultural advancements.

The Evolutionary Journey of Prickles

Contrary to popular belief, the sharp projections found on roses are not true thorns.

Thorns are woody structures found on certain shrubs and trees, such as honey locusts and citrus trees.

Instead, roses feature prickles, which are epidermal outgrowths similar to hair.

These prickles have a long evolutionary history, dating back at least 400 million years.

Early ferns and their relatives exhibited prickles on their stems, a trait that has appeared and disappeared throughout evolutionary history.

Dr. Zachary Lippman, a plant biologist and genetics professor at Cold Spring Harbor Laboratory, notes that prickles have appeared in various plant lineages at different times.

The Solanum genus, which includes crops like potatoes, tomatoes, and eggplants, first developed prickles around 6 million years ago.

Today, this diverse genus includes over 1,000 species, with approximately 400 exhibiting spiny characteristics.

When a trait like prickles appears independently in various species, it is referred to as convergent evolution.

This phenomenon occurs when different species adapt to similar environmental pressures by evolving similar features.

Wings, for example, have evolved independently in birds, bats, and some types of squirrels.

Similarly, prickles have arisen independently in many plant lineages as an adaptation to protect against herbivores and compete for resources.

The Role of Prickles in Plant Defense

Prickles and thorns serve as crucial defenses against herbivores—animals that consume plants.

They also contribute to plant growth, competition, and water retention.

The exact mechanisms driving the development of prickles in ferns and other plants had remained unclear until now.

The study led by Dr. Lippman and his team has identified an ancient gene family known as Lonely Guy (LOG) as the key regulator of this trait.

This gene family has played a pivotal role in controlling the presence of prickles in various plant species over millions of years.

LOG genes are present in all plants, including ancient mosses, which are considered the first land plants.

These genes are responsible for activating cytokinin, a hormone essential for fundamental plant processes such as cell division and expansion.

Dr. Lippman explains, “Rather than a single common ancestor having prickles that spread over time, it appears that the trait was readily acquired in different lineages independently.”

Unveiling Genetic Insights Through Research

The discovery of the LOG gene family’s role in prickle formation has significant implications for both evolutionary biology and agricultural science.

By removing prickles from various plant species, including roses and eggplants, researchers have demonstrated that the LOG gene is responsible for prickle development in approximately 20 plant types. This insight provides a new tool for scientists aiming to create prickle-free plant varieties.

Dr. Tyler Coverdale, an assistant professor of biological sciences at the University of Notre Dame, emphasizes the importance of this research.

“Precise genetic modifications enable a deeper investigation into the ecological functions of physical defenses in plants. Prickles represent a significant evolutionary development that helps plants endure herbivory. Gaining insight into this mechanism enhances our understanding of the diverse adaptations plants have evolved and their effects on ecosystems.”

Advancements in Genetic Engineering

Before this study, removing prickles from plants involved breeding with varieties that naturally lacked them.

However, with the identification of the specific gene responsible for prickles, scientists can now employ advanced genome editing techniques like CRISPR to precisely modify plant DNA.

This approach allows for the creation of prickle-free plant variants with minimal impact on plant growth and fruit production.

Vivian Irish, a plant biologist and professor at Yale University, notes, “This study not only advances our knowledge of prickle evolution but also provides insights into engineering plant developmental pathways for agricultural improvement. The repeated co-option of LOG genes for prickle formation suggests that nature often repurposes existing genes for new functions.”

Implications for Agriculture and Beyond

The ability to genetically remove prickles from plants holds promise for improving agricultural practices.

For instance, desert raisins—berries grown on prickly bushes native to Australia—could be cultivated more easily without their protective spikes.

This advancement could lead to the commercialization of lesser-known produce and enhance its availability in grocery stores.

Dr. Lippman highlights the broader significance of these findings: “By understanding the genetic underpinnings of prickles, we gain insights into how mutations have shaped the food we consume. This knowledge opens up possibilities for further innovations in agriculture and plant science.”

Conclusion: A New Era in Plant Research

The recent discovery of the genetic basis for prickles marks a significant milestone in plant evolutionary research.

By tracing the origins of this trait to an ancient gene family, scientists have unlocked new avenues for exploring plant defenses and improving agricultural practices.

As research progresses, the potential for creating prickle-free plant varieties and understanding their ecological roles will continue to expand, offering valuable insights into the intricate world of plant evolution and adaptation.