Department of Biology

Jessica Duchicela’s research on mycorrhizal fungi pioneered a new understanding of plant invasion. Now she’s working to build a massive database that will help expose the secrets of this fascinating fungus.

Untangling the mysteries of mycorrhizae

Jessica Duchicela arrived in Bloomington, Indiana, in the middle of winter in 2007. She wore a light coat and shoes that would have been perfectly suitable for the climate of her Ecuadorian home but which were wholly inadequate for the harsh cold of January in the American Midwest. “I was not prepared for winter,” she says, laughing. Despite being fashionably unprepared, she had been working toward this moment for her entire career. On a Fulbright Scholarship, she was going to pursue her dream of furthering her studies in ecology.

The Fulbright launched Duchicela on a lifelong journey of researching a true ecological wonder—mycorrhizal fungi. Mycorrhizal fungi are ancient microscopic life forms found in the soils of nearly every land ecosystem: desert, forest, plains, tropical rainforest, and even tundra. Mycorrhizae thrive inconspicuously underground, but the influences they have on ecosystems are extraordinary.

Most notable is the relationship they form with plants, a symbiotic connection from which both the plant and fungi benefit. The fungi grow tiny, branching filaments (called hyphae) that snuggle up to plant roots, or often even invade the cells, forming an intimate connection between fungus and root. The hyphae can grow longer than the roots, so as the tendrils extend into the soil, they mine hard-to-get nutrients and water and deliver them to the plant. In exchange, the plant supplies the fungi with the carbon that it needs to grow and survive. This relationship is the basis for the fungi’s name: mycos (fungi) and rhiza (root).

Duchicela’s Ph.D. research on mycorrhizal fungi led to a new strategy for managing invasive plant species in Ecuador’s most treasured ecosystem—the Galápagos Islands. “Her work on the Galápagos is really pioneering,” says James Bever, Ph.D., one of Duchicela’s advisors and a professor in the Indiana University Department of Biology at the time. Later, Duchicela’s commitment to untangling the mysteries of mycorrhizae would lead her to her current mission of compiling data from thousands of studies on the fungi into one massive database that can help scientists uncover the secrets of this fascinating organism.

Duchicela’s fondness for science emerged when she was a teenager. A perceptive teacher recognized her skill and allowed her and a trusted group of friends to use the high school lab for more challenging tasks than those assigned to the class. “We were free to play in the lab to do our projects,” she says. “That was like a gift for us.” The lab became a sanctuary for her as she coped with the disappearance of her father, a military attaché, in the border conflict between Ecuador and Peru.

Duchicela’s homelife in Quito also nurtured her academic inclinations. Her mother had returned to school to study law, and her two cousins had come from a small town in Ecuador to live with them while they attended the university. “At home we were always studying,” Duchicela says. They also lived close to the public library, and from an early age, she spent hours reading and researching among its towering stacks.

Duchicela studied agricultural engineering at the Universidad de las Fuerzas Armadas–ESPE outside of Quito, Ecuador. Nestled in the Andes Mountains at 9,350 feet, Quito is the capital of the small South American country. Ecuador lies on the equator and its geography is extraordinarily diverse. Enclosed within its borders are four distinct ecosystems: the coast, the highlands (Andes), the Amazon rainforest, and the oceanic island ecosystem of the Galápagos.

A talk on soil microbes at her university piqued Duchicela’s interest in mycorrhizal fungi. For her research thesis, she investigated how the fungi might protect tomatoes, an important Ecuadorian crop, from disease.

Duchicela graduated from ESPE with honors in 2001, but in order to continue studying the intricacies of mycorrhizal fungi, as she longed to do, she would need a scholarship. Ecuadorian universities did not offer graduate programs in soil ecology nor did they have enough funding to accept graduate students.

After graduation, Duchicela’s alma mater hired her to teach a workshop on soil microorganisms at a new campus in a tropical region of Ecuador between the coast and the Andes Mountains. The campus was isolated—more than thirty minutes by car from Santo Domingo, the nearest city—but Duchicela was up for the adventure and used the opportunity to gain the skills required for winning scholarships: research experience and English language proficiency. Despite her efforts, Duchicela continued to be denied scholarships from ESPE due to a lack of experience. “Scholarship opportunities were for people who had five, eight years [of experience] working in academia,” she says. “And I remember the principal of [ESPE] telling me, ‘You have been here three years and you want to go for this scholarship, but I have people that have been here 10 years, so why should I choose you?’”

Duchicela met her husband, Roberto Terán, in 2004, and they had a son. Two years later, while Duchicela was working at ESPE’s multidisciplinary research center, a professor returned to the university after completing his studies on a Fulbright Scholarship. He knew she could win the scholarship and offered to sponsor her in the application process. Though she was unsure if she could continue her studies with a growing family, she decided to apply. “I thought, ‘Well, I do not have anything to lose.’”

After a grueling application process and a weeks-long waiting period, Duchicela received a phone call. She had been granted the Fulbright Scholarship. “That really did change my life, opening up an opportunity when I thought I might not have opportunities here,” she says. But there was a catch. Duchicela spoke limited English, so the Fulbright board required her to arrive in the U.S. six months before the start of her program to take an intensive English training course. Her family, though, would have to stay behind—the committee felt she would not adequately advance in English if she were speaking Spanish at home with her family. “My little one [was] one and a half at that time, so he was very little for me to leave him,” she says. “I thought maybe I could not do that.”

But her husband insisted she go, saying it would be a great opportunity for her to familiarize herself with a new place and a new academic system. Other Fulbright families who had been in the same situation also encouraged her, but their circumstances differed in an important way: the male left to study while the female partner took care of the family.

Duchicela eventually accepted the challenge. To communicate her absence to her son she wrote a story. “I still have the story I did with pictures: ‘Mom is going to go for a trip to a new city, and she's going to find a new place for us to live, and she is going to wait for you there.’”

At Indiana University Bloomington, Duchicela joined the James Bever and Peggy Schultz lab in the Department of Biology, which studied the role of mycorrhizal fungi in the restoration of prairie ecosystems. After completing her master’s where she showed that livestock grazing reduced mycorrhizal activity and soil stability in grasslands, she continued to work with Bever and Schultz to earn her Ph.D. She wanted to investigate the role of mycorrhizae in Ecuador’s most unique ecosystem—the Galápagos Islands.

The Galápagos Islands formed from land that rose out of the ocean around one million years ago—a blink of an eye in geologic time. Dotting the Pacific Ocean like a tiny village in a vast desert, the twenty islands lie 1,000 kilometers west of mainland Ecuador. Being isolated from the continent, they were devoid of all life when they first arose; plants and animals would have to travel the turbulent open ocean to colonize the islands’ barren shores.

The first life forms to make the journey were likely spores from mosses and ferns transported to the islands by wind. Larger animals came by sea: good swimmers such as sea lions and sea turtles hitched rides on swift currents while reptiles and small mammals may have floated there on rafts of vegetation. The seeds of salt-tolerant plants such as mangroves could have survived the long float to the islands as well.

Humans arrived in the 19th century and introduced agricultural crops from mainland Ecuador. Guava, strawberry, blackberry, and cinchona—a tree cultivated for the malaria-fighting substance, quinine, produced by its bark—were scattered across the islands’ arid landscape. Over time, these crops outcompeted the native plants, and today many of the islands’ native species are endangered. Adding to the urgency to protect these species is the fact that many of them are endemic to the islands, meaning they occur nowhere else on Earth.

Noting that the invasive species, when found on the mainland, partner with mycorrhizae, Duchicela wondered how the fungi could be giving the crops a competitive advantage over native plants on the islands. Her question took her to Santa Cruz Island, the second largest of the Galápagos archipelago. Its long history of human settlement has left its vegetation ravaged by invasive species, and as the home of the Charles Darwin Research Station, Santa Cruz would be the ideal island for Duchicela’s project.

With the help of a local botanist, Duchicela identified areas of the island that were heavily invaded and those that were still brimming with native species. For ten months, she lived on the island, working in the field and in the lab. On field days, she set out to the plots in a burly pair of hiking boots to protect her feet and ankles from the island’s spiny cacti. By 6 a.m. she would be kneeling in her hiking pants gathering soil samples into Ziplock bags. Ecuador’s extreme equatorial heat during the dry season and frequent downpours during the rainy season added climatic challenges to fieldwork. In the lab, Duchicela analyzed the soil samples to determine if the mycorrhizal activity was different in the invaded plots versus those where native species still ruled.

What she found turned out to be a monumental discovery—while the fungi boosted invasive species’ growth and enhanced their ability to access water and nutrients, this effect on native species was negligible. Native plants on Santa Cruz Island did not benefit from mycorrhizal fungi.

This pattern is opposite from that observed on continental mainlands across the globe where native plants are more likely to form symbioses with mycorrhizae than invasive species. As a result, restoration ecologists on the mainland often fertilize soils with mycorrhizae to encourage native plant growth. Duchicela showed that on islands like the Galápagos researchers would need to find a different method for restoring native plant species.

The groundbreaking work presented a conundrum for island farmers who use mycorrhizal fungi to stabilize and fertilize the soil for crop production. One of Duchicela’s advisors, Peggy Schultz, Ph.D., says the new knowledge put land managers in an uncomfortable position, forcing them to decide between developing healthy soils for agriculture—a must for feeding the remote islands’ 25,000 residents—or conserving the islands’ precious native plants.

The Galápagos National Park, ironically, was also at fault for dispersing mycorrhizal fungi. In their efforts to save native plants, the park’s restoration ecologists had been growing native plant seedlings in soil that contained mycorrhizal fungi because this soil, with its earthy smell and dark color, appears healthier than the islands’ native soil, which is sandy and dry. Thus upon transplantation of the seedlings, the mycorrhizae spread throughout the island.

In light of Duchicela’s findings, the park transitioned to using the Galápagos’ natural soil to grow the seedlings. Duchicela also convinced the farmers to refrain from importing new strains of mycorrhizae to the island, though they would continue to use existing ones as fertilizer. “Those were the two things that, after many discussions, we were able to find together,” says Duchicela.

1. Jessica Duchicela, Principle Investigator, Departamento de Ciencias de la Vida y de la Agricultura, Universidad de las Fuerzas Armadas-ESPE. Skype interviews on October 1, October 5, and December 2, 2020. Email correspondence on October 13, 2020.
2. James Bever, Senior Scientist, Department of Ecology and Evolutionary Biology, University of Kansas. Phone interview on October 12, 2020.
3. Peggy Schultz, Associate Specialist, Kansas Biological Survey and Environmental Studies Program, University of Kansas. Phone interview on October 12, 2020.
4. Duchicela J., Bever J.D., and Schultz P.A. “Symbionts as Filters of Plant Colonization of Islands: Tests of expected patterns and environmental consequences in the Galapagos.” Plants 9, no. 74 (2020). DOI: 10.3390/plants9010074.
5. Duchicela J., et al. “Non-native plants and soil microbes: potential contributors to the consistent reduction in soil aggregate stability caused by the disturbance of North American grasslands.” New Phytologist 196, no. 1 (2012). DOI: 10.1111/j.1469-8137.2012.04233.x.
6. Simard S., et al. “Mycorrhizal networks: mechanisms, ecology and modeling.” Fungal Biology Reviews 26 (2012). DOI: 10.1016/j.fbr.2012.01.001.
7. Parniske, Martin. “Arbuscular mycorrhiza: the mother of plant root endosymbiosis.” Nature Reviews Microbiology 6 (2008). DOI: 10.1038/nrmicro1987.
8. Chaudhary V.B., et al. “MycoDB, a global database of plant response to mycorrhizal fungi.” Data 3, no. 160028 (2016). DOI: 10.1038/sdata.2016.28.
9. “Galápagos Islands.” Encyclopaedia Britannica. Accessed October 13, 2020. https://www.britannica.com/place/Galapagos-Islands.
10. “Species Arrival to Galapagos.” Galapagos Conservancy. Accessed December 6, 2020. https://www.galapagos.org/about_galapagos/about-galapagos/history/species-arrival-and-evolution/.
11. “Join the Finding Ada Network.” Finding Ada Network. Accessed December 6, 2020. https://findingada.com/finding-ada-network/join-the-finding-ada-network/.