Firmly Rooted

by Brenda Bollinger

Bryan-Thines

Professor Bryan Thines’ interest in molecular plant biology arose from his fascination with the array of chemicals made by plants, many that are advantageous to humans.

“Taxol, for example, from the Pacific Yew tree, is used as a chemotherapeutic agent for breast cancer,” said the assistant professor of biology.

Conducting research and teaching courses in the labs and classrooms of the W.M. Keck Science Department, Thines’ forays into the infinitesimal, genomic mechanisms of plants are resulting in information that may combat the impact of climate change and help create environmentally sound products like biofuel. His mission is not only discovery—he is also equipping students from Scripps, Pitzer, and Claremont McKenna Colleges with the knowledge, experience, and tools to become future leaders in interdisciplinary scientific fields.

Hunched over an array of sophisticated equipment in the Keck laboratories, Thines and his students examine how plants cope with environmental stressors, particularly elevated temperatures, as related to the circadian clock. Like plants, humans also function with circadian clock rhythm, represented best in the standard sleep-wake cycle.

Plants synchronize their life processes, including stress responses, to specific times— much as human beings arrange their activities to sensibly match times of the day and night.

“Certain physiological processes are set to occur during the day, and others are set to happen at night,” Thines said. “It turns out that by anticipating these biological events, plants can become very efficient at what they do, especially when timed with what’s happening in the environment. For example, the circadian clock enables a plant to anticipate that day is coming, so it turns on a certain gene at dawn just prior to when day starts, and turns it off at night so as not to waste energy. They can maximize the efficiency of biological processes by getting the timing right.”

But when atypical environmental shifts occur, such as an increase in temperature, a plant’s timing can discombobulate and negatively affect its core life processes: growth, photosynthesis, seed germination, and flowering.

“The circadian clock acts as a fact checker—’okay, it’s daytime, it’s supposed to be hot. This is fine,'” said Thines, channeling a plant. “Whereas at night, the plant knows it’s night. But if it’s unusually hot, plants take this as a sign that there are major environmental anomalies, which can cause problems.”

Much of the time, plants can successfully cope with these shifts using sophisticated stress responses, an intricate process that renders Thines awestruck. “I find it amazing that plants have to deal with whatever the environment throws at them, and they have all these interesting and exquisite molecular and biological responses that allow them to live under conditions that aren’t ideal,” he said.

But hyper-activation of the stress response can divert resources away from normal growth and development, causing problems such as early flowering, which makes the plant much less robust and dramatically shortens its life: “Okay,” began Thines, again speaking as a plant, “I might not live as long as I thought, so I’m going to crank out my kids earlier.”

This is a big deal, according to Thines. Because it doesn’t take much of a temperature change to induce drastic biological responses in plants, climate change could have dramatic consequences for the plant world.

 

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