“Plants grow well when light, temperature and nutrients are all in balance,” says Chan Yul Yoo, assistant professor of biology at the University of Utah. “But when conditions turn extreme, such as drought, extreme heat or shifting seasonal patterns, plants can’t just pick up and relocate. Instead, they rely on molecular sensors to constantly read their surroundings and translate those cues into decisions about growth and development.” 

Understanding exactly how those sensors work, down to the level of individual protein complexes, could help scientists engineer crops and ecosystems withstand a hotter, less predictable future.

Recognizing the promise of this research, the National Science Foundation has awarded Yoo the prestigious Early-Career faculty award. Totaling $1.27 million, the five-year award will fund this research through 2031.

A work around

Central to Yoo’s lab investigations is phytochrome B, a protein which senses both light and temperature. In daylight, the protein moves into the nucleus, the cell’s control room, and clumps together with other proteins into structures called photobodies. Photobodies don't just sense whether it's light or dark; they help plants interpret their environment and translate that information into instructions for nearly every stage of life, including how plants build chloroplasts, the structures that capture sunlight and bring in carbon (as carbon dioxide) for the plant's energy needs and growth. 

In darkness, the photobodies dissolve and the protein drifts back out into the rest of the cell, where it likely teams up with a different set of partners. “Photobodies are not permanent structures,” says Yoo, “They form, dissolve, and change partners as light and temperature shift—and that changing lineup is what tells the plant how to grow.”

Exactly how these nuclear and cytoplasmic complexes change in composition and function, however, is still poorly understood. What is known is that molecular compositions of photobodies shift continuously as conditions change, allowing them to process multiple environmental signals at once, a work around for plants which are not mobile but still need to adapt. 

Identifying unknown components

Using confocal imaging and proximity labeling—a technique that chemically tags whatever proteins are standing closest to phytochrome B at a given moment—Yoo’s team will map the composition of these complex changes and how they ripple outward to affect the genetic networks that control plant growth and development. The work is expected to identify previously unknown components of these signaling hubs and clarify how plant cells reorganize them in real time to prioritize different environmental cues.

Beyond its implications for basic cell biology, the project is designed to generate resources, including genomic ones, that other researchers can build on—knowledge that could help scientists modify crops for greater resiliency and take action to protect forests and native plant species. “A central piece of the award’s broader impact,” says Yoo, “is the launch of the Utah Plant Biology Symposium, a new statewide gathering that we will initiate to connect plant researchers across Utah.” 

By Tanya Vickers, School of Biological Sciences