Plant pathologist finds connections between plant and human health

By Olga Kuchment

Libo Shan has landed her dream job, and she’s on a quest to help others succeed, too.

Shan’s research, in the Department of Plant Pathology and Microbiology, aims to improve the health of plants and even has implications for humans. In 2013, the associate professor won the College of Agriculture and Life Sciences Dean’s Award for Early Career Research. Though Shan is an accomplished researcher, at the core of her work is bringing up the next generation of biologists.

“I want to see more talented undergraduates going into our field,” Shan says. “Biology is the most fascinating science. We will never stop addressing its questions.”


Dr. Libo Shan and her graduate student, Kevin Cox.

Protecting plants
Shan’s research focuses on plant immune systems. All plants are born with an immune system that detects and fights most types of infection. For example, this innate immune system recognizes certain molecules that are carried by bacteria and other microbial intruders.

Although plants are experts at fighting disease, their defenses can be breached. Pathogens employ sophisticated strategies to dampen the plant immune response. Shan works to understand the battle between pathogens and plants at genetic, molecular, and biochemical levels. Her lab studies cotton, algae, and the small flowering plant Arabidopsis thaliana, which has been studied extensively in plant biology and genetics.

Boosting immunity
When microbes invade plants, they often trip the molecular sensors of the innate immune system. Other parts of the innate immune system, acting like police officers that respond to a jewelry store alarm, seek out and apprehend the invaders. And other molecules, including those called negative regulators, essentially turn down the volume of the alarms, as though not wanting to call the cops twice for the same break-in. Some pathogens take advantage of this lapse in vigilance to successfully infect plants.

In the past several years, Shan’s team of postdoctoral fellows, graduates, and undergrads has learned more about this “volume control” feature of plant immune system.

“Let’s say we want to boost the immune response in plants,” Shan says. “We can control the negative regulator, and we can also engineer the immune sensor to be more sensitized. The type of immune response we are studying is very broad. So this applies to a broad spectrum of pathogens.”

The lab’s results may eventually offer crop growers the power to engineer plants that are more resistant to different pests, with higher yields.

“If we can decrease pest damage to crops, this would leverage our capacity to feed the world,” Shan says.

Animal and human health
Animals’ and humans’ immune systems are more complex than those of plants, but their building blocks are similar. Plants such as Arabidopsis are relatively easier and quicker to work with in the lab than animals, yet have many similar innate immunity components. So, studies of the plant innate immune system can provide insights into animal and human health.

For example, the innate immune system plays an essential role in allergies and autoimmune diseases in humans. Shan’s experiments with plants could help explain long-standing mysteries such as why children raised in clean environments are more likely to develop allergies. The research may also pave the way toward treatments for allergies that do more than simply mask symptoms, Shan says. Parts of the work are supported by a grant from the National Institutes of Health.

When Shan began training in biology as an undergraduate, she wanted to become a teacher. And today students are closely involved with much of the work in her lab. Shan strives to impart in them a passion for biology and an appreciation for plants. To lab, she brings photos and stories.


Dr. Libo Shan and her graduate students, Wenwei Lin (left) and Kevin Cox.

“In the cold winter, I see a tiny flower,” Shan says. “Most people wouldn’t notice it but to me, this is something astounding. How come this little guy is alive?”

When students hits a snag in lab, Shan tells them to be patient.

“I tell my students: You are so very talented,” Shan says. “The challenge is how you dig out your talent, how you find it.”

How did Shan end up studying plants? As an undergraduate student at Beijing Normal University in China, she wanted to become a biology teacher. After dissecting animals in class, she chose plants.

“Maybe I was a typical girl?” Shan says. “I hated to see the blood, I hated the smell.”

She has now studied plants for years. Her appreciation for them has only deepened.

“Plants feed themselves and they also produce food for all others in this universe,” Shan says. “I have a lifetime of questions to address. So I think I made the right choice.”

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