DNA Analysis Sheds Light on Invasive Weed Strategies

A groundbreaking technique for analyzing the DNA of ancient plant specimens has provided researchers with a valuable tool in the fight against the proliferation of invasive plant species.

Scientists from Monash University and the University of Melbourne discovered that the rapid adaptation of invasive plants is fueled by their capacity to gain and lose genes, a process referred to as “copy number variation.”

This revelation emerged during their investigation of ragweed, an invasive and harmful weed that originated in North America and has since spread to Europe and Australia.

Ragweed is known for its aggressive invasiveness. It poses significant challenges to agriculture and is a major source of pollen that triggers hay fever.

The study examined DNA samples from plants collected as far back as 1830, uncovering remarkably similar adaptation patterns in both native and invasive populations.

Lead researcher Jonathan Wilson indicated that the results imply that the same genetic mechanisms are employed to address similar environmental challenges when these plants invade new regions.

Dr. Wilson conducted this research while pursuing his PhD at Monash University and is currently a research fellow at the University of Melbourne.

We developed a new method to detect large gains and losses of DNA, even in old and degraded DNA from museum specimens. This allowed us to track the evolution of these large genetic changes during the invasion and uncover evidence that natural selection likely contributed to their spread.”

Jonathan Wilson, Study Lead researcher and Research Fellow, University of Melbourne

The study also pinpointed the gain or loss of the gene targeted by the herbicide glyphosate, which may offer crucial insights into the development of herbicide resistance and potentially lead to more effective weed management strategies.

This knowledge could be instrumental in developing better strategies to mitigate the spread of invasive weeds. This will have a huge impact on our farmers who are constantly dealing with the threat of invasive plants. In the case of ragweed in particular, it is already a major contributor to hay fever in Europe, and we hope this research will help control the weed before it becomes a big problem in Australia.”

Jonathan Wilson, Study Lead researcher and Research Fellow, University of Melbourne

Senior researcher and Associate Professor at Monash University, Kathryn Hodgins, noted that the findings provide rare insights into the rapid evolution of ragweed, further highlighting the significant role of gene gain and loss in facilitating adaptation.

Gains and losses of genes, or copy number variants, are a key driver of adaptation, yet they are often overlooked in many studies of diverse species due to technical challenges. Our study demonstrates that we can leverage existing datasets to detect these variants, opening the door to important new insights that have largely gone unexplored.”

Kathryn Hodgins, Associate Professor and Study Senior Researcher, Monash University