How Plants Cope with Stress at the Molecular Level

UMass Amherst biochemist studies a protein’s role in regulating nitric oxide
Left are normal plants and at right, plants deprived of S-nitrosoglutathione reductase (GSNOR), a regulatory protein that plays an important role in plants’ coping skills with stress in their environment. UMass Amherst biochemist Elizabeth Vierling and colleagues will use cutting-edge technology and instruments to follow a lead suggesting among other things that plants lacking GSNOR are sensitive to heat stress, make fewer seeds and suffer damage from excess nitric oxide. Courtesy UMass Amherst

AMHERST, Mass. – Biochemist Elizabeth Vierling at the University of Massachusetts Amherst recently received a three-year, $682,982 National Science Foundation grant to study how plants respond, at the molecular and cellular level, to stress in their environment and the role of a regulatory protein called S-nitrosoglutathione reductase (GSNOR).

Vierling has spent much of her career studying how plants respond to their environment, particularly in stressful conditions such as high temperature. She explains, “I’ve been looking into how individual cells cope and survive in conditions not optimal for growth and reproduction. One very interesting thing we’ve seen over the years is that plant cells respond in a very similar way to many other types of cells, including human cells. GSNOR is found in organisms from yeast to plants to humans. It plays an important role in controlling nitric oxide (NO) levels.”

The scientists who first reported NO in humans received a Nobel Prize in 1998, which emphasizes its importance, she points out. In plants, NO is a necessary signaling molecule that helps plants conserve water and produce seeds. But as a free radical, it can also damage cells if levels get too high.

In her new series of experiments in the model plant Arabidopsis, Vierling and colleagues will use cutting-edge technology and instruments to follow a lead suggesting that GSNOR eliminates excess NO inside cells, and that plants lacking GSNOR are sensitive to heat stress, make fewer seeds and suffer damage from excess NO.

The research aims to discover the mechanism by which GSNOR regulates NO and how it may alter NO perception. This project has potential to uncover the ways plants adapt to stresses such as heat and drought, and could inform efforts to improve plant fertility. As climate change and shifting economic patterns affect the availability of water and other resources, Vierling points out, “it is increasingly important to understand the control of plant growth, development and productivity.”  

Specifically, they already know GSNOR’s crystal structure, she says, and that it interacts with nitrogen metabolism and that too much NO damages plants. Their experiments will examine how GSNOR activity is regulated and will try to determine how it may control important plant traits such as flower development and seed production. They will also measure how GSNOR mutations alter the balance of anti-oxidantsin living plants. Anti-oxidants are as important for plant health as they are for human health.

Vierling says this work is possible because of recent technical advances and UMass Amherst’s state-of-the-art instruments. “We wouldn’t be able to propose what we are doing without the new mass spectrometry equipment made possible by the Massachusetts Life Sciences grant of $95 million in 2013. It is pretty thrilling to use mass spectrometry, which can detect differences in mass as small as less than one half atom of hydrogen, to directly see changes that may regulate GSNOR,” she adds.

In addition to involving one postdoctoral fellow and a graduate student, the project will provide opportunities for UMass Amherst undergraduates, high school students and teachers from Amherst Regional High School to have lab research experience. The project will support an evening information session for the high school students where they talk to current UMass undergraduates about studying science, after which they may spend a day with the undergrads on campus.