Genetic Map of Yerba Mate Offers Insight into Evolution of Caffeine Biosynthesis

Yerba mate, along with tea and coffee, is one of the world's most popular caffeinated beverages. Widely consumed in South America, this remarkable plant is rich in diverse, bioactive compounds that contribute many health benefits.

An international group of researchers has mapped the yerba mate genome, providing insights into the biosynthesis of caffeine in yerba mate. This new information provides opportunities for creating plant varieties with new characteristics.

The work, led by the University of Buenos Aires, involved scientists from EMBL Hamburg and several institutes in Argentina, Brazil, and United States.

Evolution of Caffeine in Yerba Mate

To uncover key aspects of yerba mate's genetic makeup, the scientists employed genome analysis. It revealed surprising facts about the plant's biochemistry and its evolutionary history – in particular, the evolution of caffeine biosynthesis.

I discovered that an ancestor of yerba had duplicated its genome approximately 50 million years ago. 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."

Federico Vignale, study's first author and an EMBL Hamburg postdoc

Caffeine is produced by several unrelated plant species, such as yerba mate and coffee, through similar metabolic pathways for its biosynthesis. Yet, the scientists discovered that the genes involved in these pathways evolved independently.

"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 Adrián Turjanski, the project leader and a researcher at the Institute of Biological Chemistry in the Faculty of Exact and Natural Sciences at the University of Buenos Aires (IQUIBICEN, UBA-CONICET).

The parallel evolution of caffeine synthesis in yerba mate and coffee led scientists to suspect it plays a crucial role in plant survival, potentially functioning as a defence mechanism.

Through detailed structural, experimental, and bioinformatic analysis, the scientists identified which pathways led to a specificity in caffeine biosynthesis that was different from the coffee plant.

Paving the Way for Next-Generation Yerba Mate

The findings not only revealed yerba mate's evolutionary history, but they might also open opportunities to advance how it is cultivated.

"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."

The team stressed that it is in this context that the foundation for this kind of work has been laid, so other groups working specifically with yerba mate can carry out new studies and, in turn, the industry can create new strains that either assist growers or satisfy user's tastes.

For Vignale, the cultural significance of yerba mate in South America goes beyond its scientific implications, adding a deeply personal dimension to this research.

"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," he said. "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

The project was led by the Faculty of Exact and Natural Sciences at the University of Buenos Aires in collaboration with scientists from EMBL Hamburg, as well as IQUIBICEN-CONICET, Universidad Nacional de Misiones, and Universidad Nacional del Nordeste in Argentina; Instituto Tecnológico Vale in Brazil; and the University of Illinois at Urbana-Champaign, Western Michigan University, and University of California Davis in the United States.

To uncover the caffeine biosynthetic pathway in yerba mate, EMBL Hamburg provided key insights through structural modelling and molecular docking. The expertise provided by Vignale and his colleague Lucas Defelipe, members of EMBL Hamburg's García Alai Team, played a crucial role in this process.

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

Vignale's first interaction with EMBL was through CABANA, a project run by an international consortium of Latin American organisations and EMBL-EBI. Funded by the UKRI Global Challenges Research Fund, it aimed to strengthen bioinformatics capacity across Latin America and supported research to address challenges faced by developing countries. The CABANA project itself aimed to tackle three global challenges: communicable disease, sustainable food production, and protection of biodiversity.

Vignale added, "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."

This article has been adapted from a press release by the Faculty of Exact and Natural Sciences at the University of Buenos Aires.