Researchers at The Samuel Roberts Noble Foundation and Michigan State University (MSU) recently received a four-year, $3 million grant from the National Science Foundation (NSF).

The grant will enable Wolf Scheible, Ph.D., principal investigator, and co-principal investigators, Michael Udvardi, Ph.D., and Patrick X. Zhao, Ph.D. (all with the Noble Foundation), and Hideki Takahashi, Ph.D. (MSU), to identify and study targeted molecules, small signaling peptides (SSPs), in a model legume species, Medicago truncatula, as well as alfalfa, a commercially significant crop.

“We want to understand how these under-studied molecules affect plant development, especially root growth and nodulation,” Scheible said. “Currently, all we know is that a few such peptides are key components in signaling pathways that manage the internal developmental decisions plants make.”

Noble Foundation researchers further expect that SSPs, which are encoded by many, often poorly marked genes, may also control plant metabolism, plant-microbe interactions and nutrient stress tolerance. This grant will enable this exploration.

Legumes have the ability to acquire and fix nitrogen efficiently through the use of nodules, specialized plant organs that develop on the roots and work symbiotically with rhizobia, a soil bacteria. Legumes’ ability to fix nitrogen in the soil enhances soil productivity and soil health.

As part of the research project, the scientists will identify SSP-coding genes in Medicago truncatula, then focus on the genes that display altered activity in the presence of nutrient-limited conditions. Once the genes and their encoded peptides have been identified, the researchers can test the effect of identical, synthetic peptides on root development and root nodule formation.

Researchers can then assess legumes, including alfalfa, having such synthetic peptides to assess their ability to fix nitrogen in such nutrient-limited conditions.

This research will increase understanding of a class of very important genes and potentially identify key regulators of important plant traits such as root system growth, root architecture and nodule development. “

Once we better understand SSPs and their coding genes, we may be able to change the way we do translational research,” Scheible said. “SSPs may serve as a new class of mechanisms to obtain plants with improved root systems and plant-microbe interactions, with a target to boost plant productivity and efficiency.”