How plants develop specialized metabolites for survival

A study from UC Davis is providing brand new insight into how plants evolve unique defense mechanisms known as specialized metabolites. The experts found that these protective chemicals are shaped by a combination of genetics, geography, and environmental conditions.

“Plants produce diverse metabolites to cope with the challenges presented by complex and ever-changing environments. These challenges drive the diversification of specialized metabolites within and between plant species,” wrote the researchers.

“However, we are just beginning to understand how frequently new alleles arise controlling specialized metabolite diversity and how the geographic distribution of these alleles may be structured by ecological and demographic pressures.”

Each plant has a unique profile of specialized metabolites that are linked to genetic variants that have evolved over years in response to environmental conditions.

“We already know that environmental pressures such as the type of herbivores that prey on plants influences the specialised metabolites plants produce,” said study first author Ella Katz. 

“We wanted to understand how the intersection of environmental pressure, demography and genomic complexity gives rise to the pattern of metabolic variation across a plant species.”

To investigate, the experts measured the variation in specialized metabolites across almost 800 seed samples of the model plant species Arabidopsis thaliana collected from across Europe.

The researchers analyzed three locations in the plant genome known to influence A. thaliana’s survival fitness. They also examined the entire genome to find genes linked to metabolite production. 

The researchers found large variability in the types of specialized metabolites, or chemotypes, in central Europe compared to northern Europe. They identified two predominant chemotypes that were clearly separated by geography.

The study also suggests that the relationship between environmental conditions and specialized metabolites varies across different regions in Europe. For example, even if higher levels of precipitation were linked to a certain chemotype in southern Europe, it would not be the same in northern Europe.

“Our work provides a new perspective on the complexity of the forces and mechanisms that shape the generation and distribution of specialized metabolites and affect the plant’s ability to survive in a changing environment,” said study senior author Professor Daniel Kliebenstein.

“Using a larger plant population from other locations around the world will enable us to deepen our understanding of the evolutionary mechanisms that determine the variation in a population.”

The study is published in the journal eLife.

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By Chrissy Sexton, Earth.com Staff Writer