College of Agriculture & Natural Resources Department of Plant, Soil and Microbial Sciences

EAST LANSING, Mich. – Michigan State University (MSU) plant pathologist Brad Day has received a nearly $1 million grant from the National Science Foundation (NSF) to extend his study on how plants, at the cellular level, respond to disease threats.

The project has been funded by NSF for the past three years and will continue for another three. To date, Day and his colleagues have discovered that much more than immunity is involved in fending off disease. He said processes required for the growth, development and reproduction of plants are also instrumental.

“What we’re learning is that plant immunity is not a narrowly defined process. Rather, it’s a broader, integrated mechanism that uses the entire cell — and organism — to respond to pathogen infection,” said Day, a professor in the Department of Plant, Soil and Microbial Sciences.

The work is intended to help define how stress signals are recognized, decoded, translated and communicated to the whole plant. The goal is to uncover the mechanisms that plants use to survive in environments where the threat of pathogen infection is high and environmental conditions favor pathogens over plants.  

Sheng-Yang He, University Distinguished Professor in the Department of Plant Biology, is the co-lead of the grant with Day.

“The Day Lab is known for this type of research,” He said. “We are hoping that results from this continuation project can guide new solutions to improve crop resilience against many plant diseases.

“This is one of those interesting projects that focus on poorly understood ‘modules’ of disease resistance mechanisms in plants. In this case, how plant cytoskeleton (what supports the cell and gives it structure and shape) is related to immune signaling.”

Researchers have discovered that one protein in particular, CPK3, plays a major role in how cells react to pathogens, and trigger immunity and response.

“If you think of a cell as a bicycle wheel, all of the spokes are the processes of the plant and they all come down to a singular point,” Day said. “We hypothesize that at the point, this protein – an immune-signaling kinase called CPK3 – represents a hub for integrating multiple physiological processes, including immunity, and regulates them.”

Day examined how the actin cytoskeleton – that which gives a cell its shape and structure – regulates a cell’s response to pathogens. The actin cytoskeleton, a network of proteins that together with the other components such as microtubules and intermediate filaments, is responsible for essential cellular processes.

“What we've identified is that this regulator of actin cytoskeletal dynamics not only represents the key unknown piece of how actin (a protein that forms the contractile filaments of muscle cells) is regulated, but it represents a new hub on how immunity is regulated, and signifies a target that pathogens attack during their infection,” Day said.

The project will use a combination of microscopy-based techniques and biochemistry to uncover the signals that plants use to defend against pathogen infection. The researchers eventually want to learn how plants determine if a signal is positive or negative and how that regulates the immune system.

In addition to examining the impact of CPK3 on plant pathogen resistance, Day said he hopes to explore how plants and pathogens evolve.

“I think one thing this study really does is illustrates the phenomenon that plants and their pathogens co-evolve,” Day said. “Humans don't typically co-evolve with their pathogens. If we did, we'd have a hard time overcoming them with antibiotics and other treatments. The research indicates, however, that plants typically do co-evolve with their pathogens."

Day said his research sheds light on how pathogens attack during infection.

“When pathogens infect a cell, they have evolved to attack one thing in the cell that will shut down as many processes as possible,” Day said. “The pathogens have decided, ‘I'm going to attack CPK3.’ So that's really one of the key findings of this manuscript.”

A portion of the grant will also fund an outreach program designed to educate the general public on plant research. The research team will host educational sessions on the relationship between basic agricultural research and food.

To do this, the scientists working on this project, including researchers in health and nutrition at MSU, will partner with the Lansing Capital Area Library system to educate families on topics related to food production and nutrition. Researchers plan to hold a series of workshops and hands-on activities in several of the Capitol Area District Libraries to share the significance of agriculture.

“I'm really proud of the outreach that we're doing with this project as well,” Day said. “We get really geeked-up about the science, and I'm super excited about that. But of all the grants that I've been funded on, this one is probably the most dynamic in terms of the outreach. I think it has some important contributions to make.”

Five-percent of the overall grant budget, or $45,000 over three years, will be dedicated to the broader impacts aspect of the grant.

The Day Lab will also partner with the Research Experience for Undergraduates in Plant Genomics to provide learning opportunities for undergraduate students.

Day said the outreach programs funded by the NSF grant will be announced at a later date.