Caffeine evolution in plants: The surprising story of yerba mate 

Yerba mate is an herbal tea that ranks among the world’s most popular caffeinated beverages. Beloved in South America for its invigorating properties, this versatile plant contains an abundance of bioactive compounds known to promote various health benefits. 

Recently, an international research team achieved a significant milestone: they successfully mapped the yerba mate genome. The study is shedding new light on how caffeine is synthesized in this plant and opening avenues for developing enhanced varieties.

Evolution of caffeine in yerba mate

The project was led by the University of Buenos Aires, with participation from the European Molecular Biology Laboratory (EMBL) Hamburg and other institutions in Argentina, Brazil, and the United States. 

Through genome analysis, the scientists uncovered surprising insights into yerba mate’s evolutionary history – particularly its pathway for producing caffeine.

“I discovered that an ancestor of yerba had duplicated its genome approximately 50 million years ago,” said Federico Vignale, the study’s first author and an EMBL Hamburg postdoctoral fellow. 

“This ancestral duplication may have been key in the evolution of its metabolic complexity, allowing it to synthesize a wide range of bioactive compounds, such as terpenes, flavonoids, phenols, and xanthines, known for their antioxidant, anti-diabetic, and nervous system stimulant properties. Of all these compounds, my interest focused on caffeine.”

Although caffeine appears in multiple unrelated plant species such as yerba mate and coffee, the researchers discovered that the genes behind its production do not share a single evolutionary origin.

Adrián Turjanski, the project leader, is a researcher at the Institute of Biological Chemistry in the Faculty of Exact and Natural Sciences at the University of Buenos Aires.

“We came to understand in detail that the genes do not have a common ancestor, but come from separate origins, and that both yerba mate and coffee came to have caffeine biosynthesis by evolving along convergent pathways,” said Turjanski. 

Because yerba mate and coffee independently evolved to produce caffeine, scientists suspect that this compound plays a crucial protective role, potentially defending these plants against insects or other threats.

Through in-depth structural, experimental, and bioinformatic work, the team also showed how yerba mate’s specific route to caffeine biosynthesis sets it apart from coffee.

Genetic insights into yerba mate

This genomic breakthrough not only illuminates yerba mate’s past but also hints at a future of optimized cultivation. Armed with precise genetic insights, researchers can now create decaffeinated strains, boost desirable health-promoting compounds, or breed plants adapted to a broader range of environments.

“By reading the genome you would know how to intervene and modify the plant,” Turjanski said. “One could propose making it richer in certain characteristics, for example, a decaffeinated yerba mate, or one that is better adapted to other lands, and thus expand its cultivation.”

These findings establish a foundation for subsequent research efforts, enabling breeders and industry specialists to refine the plant to meet emerging consumer preferences and agricultural demands.

A cultural touchstone

For Vignale, the personal resonance of sequencing yerba mate’s genome runs deep. Beyond the scientific intrigue, yerba mate stands as a defining element of South American life.

“Yerba mate, for me, represents the most beautiful thing about the culture of my home country, Argentina – a drink that unites us, accompanies us, and is present in every moment of our lives,” said Vignale. 

“That’s why I didn’t hesitate for a second to accept the challenge. Sequencing the yerba mate genome felt, in a way, like sequencing Messi’s genome.”

Collaboration across continents

Under the direction of the Faculty of Exact and Natural Sciences at the University of Buenos Aires, the project integrated expertise from the U.S., Europe, and South America.

To clarify how caffeine biosynthesis differs in yerba mate, EMBL Hamburg contributed structural modeling and molecular docking insights. 

Vignale, alongside colleague Lucas Defelipe of EMBL Hamburg’s García Alai Team, played a key role in unraveling the molecular steps in this specialized pathway.

“This experience taught me the true value of interdisciplinary work and to grow together with scientists from different specialties,” Vignale said.

Vignale initially connected with EMBL through the CABANA project, an initiative coordinated by Latin American organizations and EMBL-EBI. Funded by the UKRI Global Challenges Research Fund, CABANA focuses on enhancing bioinformatics capacity across Latin America to tackle challenges in communicable diseases, sustainable food production, and biodiversity.

“The CABANA project has not only strengthened my bioinformatics skills, which were essential for carrying out this research, but it also provided the necessary funding to complete the study,” Vignale added.

The future of yerba mate

With its genome now comprehensively mapped, yerba mate stands at the threshold of a new era in cultivation and consumption. 

From potential decaffeination to region-specific breeding, the ability to hone the plant’s genetic traits heralds promising developments in agriculture and industry. 

As research continues, both farmers and consumers can look forward to innovative strains that retain yerba mate’s cherished cultural significance while expanding its global reach.

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