Space station experiment to probe plant disease risks for future moon and Mars missions

As NASA and its partners prepare for longer human missions beyond Earth, University of Florida researchers are investigating a challenge that could affect astronauts' ability to grow fresh food in space: plant disease.

The university's MVP-Plant-02 investigation, launched to the International Space Station on Oct. 13, will examine how plants respond to a fungal plant pathogen in microgravity. The research will help scientists determine whether the space environment changes a plant's defenses against disease and could make infections more severe.

Led by UF/IFAS researchers Andrew C. Schuerger, Ph.D., Robert Ferl, Ph.D., and Anna-Lisa Paul, Ph.D., the investigation brings together expertise in plant pathology and plant physiology from across UF's Institute of Food and Agricultural Sciences. The science team members are combining decades of experience studying how phytopathogens develop on vegetable crops and how plants grow and respond to the space environment.

"As humanity begins to establish bases on the moon and Mars, crews will benefit from the production of fresh fruits and vegetables in habitats called bioregenerative life support systems," Schuerger said. "Wherever plants and humans go, plant pathogens are soon to follow."

Bioregenerative life support systems use plants and other biological processes to help provide food and regenerate essential resources, including oxygen and water. Such systems could reduce astronauts' dependence on supplies transported from Earth, but they will need to remain productive and healthy over extended missions.

Understanding how plant diseases develop in space is an important step toward making those systems reliable.

Studying plant defenses in microgravity

MVP-Plant-02 will examine the interaction between Arabidopsis thaliana, a small flowering plant related to mustard, and Golovinomyces cichoracearum, a fungus that causes powdery mildew.

The team will investigate whether the fungus develops more aggressively in microgravity and how the plant's gene activities change as the disease progresses. By studying both disease development and gene expression, researchers hope to better understand the biological processes underlying plant responses to infection in space.

The investigation will use the Multi-Use Variable-g Platform, or MVP, a system developed by Redwire Space Technologies Inc. that enables experiments aboard the space station to be conducted under different gravity conditions. Researchers will compare plants grown in microgravity with plants maintained at Earth-like gravity aboard the station, as well as a separate ground control at Kennedy Space Center.

This approach will allow the team to distinguish the effects of microgravity from other factors associated with growing plants in space.

The experiment also introduces an important advance in space-based plant pathology: researchers will inoculate plants with the fungal phytopathogen after the plants are already in space.

To accomplish this, the Redwire and UF team developed the Conidia Application Device, a specialized system for applying fungal spores to plant canopies during spaceflight.

"Since we get to grow plants in microgravity from seed, all plant defense mechanisms have been suppressed or turned on by microgravity before the spores land on plant tissues," Schuerger said. "It is a much better test than inoculating seedlings on the ground before launch."

Applying the pathogen after the plants have experienced microgravity allows researchers to investigate how the space environment affects plant biology before infection begins. Previous space-based plant disease research applied the pathogen before launch.

Kylee Soltez, a UF master's degree graduate and member of the science team, helped identify the significance of the new approach and the device's role in the investigation.

"The Plant-02 team developed the first plant pathogen inoculation device for use in spaceflight," Soltez said in describing the experiment's distinction from previous research. "The Conidia Application Device will allow astronauts to perform sterile ejections of powdery mildew spores onto Arabidopsis canopies, all within a closed system."

Soltez's participation also reflects the project's role in preparing the next generation of scientists to conduct research at the intersection of plant health and space exploration.

MVP-Plant-02 draws on complementary strengths within UF/IFAS. Schuerger brings more than four decades of experience developing integrated disease management strategies for plants grown in greenhouses and biological life support systems. Ferl and Paul have also brought decades of space biology experience and have led extensive research into plant growth and gene expression in space.

Their collaboration combines plant pathology—the study of plant diseases and their causes—with plant physiology and molecular biology to investigate not only whether disease occurs, but also how plants respond at the genetic level.

The project is being conducted in partnership with Redwire, which manages the MVP platform used for the investigation. The UF electron microscopy and plant molecular biology laboratories also provide critical technical support during postflight analysis.

The results could help scientists determine whether plant disease management strategies designed for Earth-based agriculture will need to be adapted for space. If disease proves more aggressive in microgravity, researchers could use these findings to develop preventive measures for future lunar and Martian habitats.

The investigation will also help establish that complex plant-pathogen experiments can be conducted aboard the space station, opening opportunities for additional research into the biological challenges of growing food beyond Earth.

What comes next

During the mission, researchers expect to receive images from a subset of the plant growth modules, allowing the team to monitor plant development. However, determining whether microgravity changes disease severity and plant gene expression will require detailed analysis of the experimental material once it is returned to Earth.

For UF researchers, the investigation represents both a scientific milestone and an opportunity to expand the university's contributions to space biology. By bringing together expertise in plant pathology, horticultural sciences and space research, the team is working toward a future in which astronauts can grow healthy plants—and produce fresh food—during missions far from Earth.