A recent biochemistry PhD graduate was part of the team of researchers to generate the first genome assembly of Yerba mate, a plant species and herbal tea native to South America. The resulting structural data, published in eLife, provides insight into the set of enzymes involved in its caffeine synthesis that could improve agricultural production of the plant.
Commonly steeped in hot water to create a beverage called mate, Yerba mate contains caffeine and is genetically related to coffee and tea. Its reported benefits include stimulation of the central nervous system and lowering of fasting blood glucose levels, which may have anti-diabetic and anti-obesity effects. It also contains antioxidant properties.
“Yerba mate is a very important plant to South America,” said Andrea Hernandez Garcia (PhD, ’23, biochemistry), co-first author of the paper and a former member of the lab of Satish Nair, Gregorio Weber Chair and head of the Department of Biochemistry. “To be able to say that we now have its genome is very powerful. It allows for in-depth research of how these valuable metabolites are produced.”
Many plants make caffeine, but their individual mechanisms differ. Caffeine production involves several potential pathways, but the route taken depends on the plant. Because Yerba mate belongs to the same genera as coffee and tea plants (called Asterids), researchers expected it would utilize a similar route.
However, Hernandez Garcia and her international colleagues were surprised to discover that enzymes in Yerba mate’s genome that catalyze the formation of caffeine were in fact more similar to those in the Rosid genera, thus sharing a closer resemblance to cacao trees and Paullinia flowering shrubs.
By comparing the structural active sites of Yerba mate enzymes to enzymes found in coffee, researchers discovered that the two enzymes have adapted to achieve the same chemistry and substrate positioning in their own unique way. Their findings highlight the adaptable nature of enzymes when faced with genetic restraints.
“There is a lot of genetic restraint that happens with the evolution of this biosynthetic pathway,” Hernandez Garcia said. “Yerba mate duplicated its whole genome early on, but it also deleted the genes similar to those that coffee plants use to make caffeine along the way. And in this case, caffeine appears to be a trait with a positive effect on the plant, as it managed to adapt other duplicated genes to produce this metabolite.”
Armed with a map of these biosynthetic pathways and a better understanding of how certain compounds are made, researchers and farmers will be able to genetically modify Yerba mate to improve production of its desired properties.
“Being Latina myself, it’s incredibly important to look at the natural resources that our culture has recognized as significant, and that have reported benefits described by Native people,” Hernandez Garcia said. “To be able to scientifically study and support the wisdom that has been shared by our ancestors has been very impactful.”
The article, "Yerba mate (Ilex paraguariensis) genome provides new insights into convergent evolution of caffeine biosynthesis,” was published in eLife and authored by Federico A. Vignale, Andrea Hernandez Garcia, Carlos P. Modenutti, Ezequiel J. Sosa, Lucas A. Defelipe, Renato Oliveira, Gisele L. Nunes, Raúl M. Acevedo, German F. Burguener, Sebastian M. Rossi, Pedro D. Zapata, Dardo A. Marti, Pedro Sansberro, Guilherme Oliveira, Emily M. Catania, Madeline N. Smith, Nicole M. Dubs, Satish Nair, Todd J. Barkman, and Adrian G. Turjanski.
