About This Project

The Chilean Soapbark Tree (Quillaja saponaria) produces QS-21, a key ingredient in COVID-19 vaccines. Due to high demand for this chemical, wild trees have been overexploited and biodiversity has dwindled. This project seeks to safeguard this natural resource with traditional conservation techniques and biotechnology for sustainable QS-21 production. With these practices, we can continue to supply this essential compound to vulnerable communities without further harming native ecosystems.

Ask the Scientists

What is the context of this research?

Saponins from Q. saponaria have traditionally been used as plant-based soap in indigenous Chilean culture as well as emulsifiers in cosmetics and foaming agents in beverages like root beer. But with the recent discovery of QS-21 as a potent vaccine adjuvant, extraction of saponin from native trees has skyrocketed. Traditional harvesting strips the tree of its bark, essentially killing the tree. Our research supports sustainable production through growing trees from seed and harvesting 6-month-old saplings. While new methods of cultivation and efficient saponin production in young plants are in development, less work has been done on conservation. There have been no soapbark tree seed storage studies to date, which is key to preserving biodiversity of this culturally important species before it is permanently lost. Thus, a key component of this project is seed banking. Our approach couples preservation of this threatened species with scalable production of its high-demand compound.

What is the significance of this project?

This project will establish the largest documented seed bank in the world for Quillaja saponaria. As a project operating out of a community lab, it is founded on open-science principles and cross-collaboration. Our research is a partnership between citizen scientists at Counter Culture Labs, researchers at UC Berkeley, and environmental stewards at Santuario Ecologico in Chile. We will develop a low-cost micropropagation setup that can be easily implemented in community labs and our seed-saving partners in Chile to expedite preservation of threatened specimens. Any novel protocols created by our group for responsible cultivation and screening of high-saponin varieties will be shared with Chilean producers of soapbark-based saponins. This project is also a first of its kind international seed collection initiative that engages local Chilean farmers in citizen science research on this valuable plant and many precious seeds will be saved for reforestation of damaged ecosystems in Chile.

What are the goals of the project?

Our primary goal is to establish a seed bank with over 100 unique trees sourced from at least 5 distinct tree populations in diverse geographic regions in Chile. To that end, we will collect seeds then store batches of seeds for months under varying temperature & humidity and record viability through germination rates. Once we have determined ideal seed storage parameters, seeds will be distributed to Chilean reserves.

Another goal is to create a low-cost indoor greenhouse setup designed for Q. saponaria germination that can be performed in community bio labs and on Chilean farms. This enables development of new propagation techniques, using tissue culture & various light recipes, to generate new practices for a sustainable supply of trees. Along the way, we will create robust protocols that can be adopted by QS-21 producers. Our final priority is to develop an inexpensive saponin content assay for high-throughput phenotyping and then label high-saponin variants for future sequencing.