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New NSF project will explore growth of corn nodal roots under drought

April 11, 2016

close-up of maize nodal roots growing in dry, cracked soil

A new NSF-funded study will explore how the nodal roots in corn plants grow through dry soil during periods of drought.

Roots are usually associated with the cause of problems. But when it comes to corn plants that can survive on less water, David Braun believes roots may be the solution.

“In a mature corn plant, the roots you see propping up, or bracing, the stalk are the nodal roots,” says Braun, who is an associate professor of biological sciences and a member of the Interdisciplinary Plant Group.

But these roots, which emerge from nodes on the stem, do more than just hold up the plant. After the first few weeks of life, the plant takes up most of its water through this particular set of roots. In so doing, these roots perform some pretty unusual growth acrobatics.

“When they first emerge from the stem, they’re growing in air. They are not in contact with water whatsoever. Yet, they are able to somehow continue to grow until they reach soil, and often, if it is a hot Missouri summer, they’re growing through a bone dry, rock-solid surface to actually get down into the water,” says Braun.

How they accomplish that, he adds, is totally unknown: “Very little is known about the mechanisms that allow nodal roots to achieve this essential feat.”

This will soon change.

Headshot of David Braun

David Braun, Associate Professor of Biological Sciences

Braun is a member of a team of MU scientists that was recently awarded a $4.2 million grant from the National Science Foundation Plant Genome Research Program to study corn nodal root growth under drought.

Using a combination of physiological and functional genomics techniques, the scientists plan to undertake a detailed study of the genetic, protein, and metabolic changes that occur in young nodal roots when growing through dry surface soils. The goal is to identify molecular pathways and specific genes important for sustaining growth under drying conditions.

“The hope is that we can use this knowledge to develop hardier corn varieties better equipped to survive, and maybe even thrive, with less water,” he says. “Of course, we also hope the knowledge we generate in corn will be broadly applicable to all of the grasses.”

Other grasses with nodal roots include wheat, barley, rice, oats, and sorghum. All together, the grasses comprise 70 percent of human caloric intake worldwide.

Developing new generations of crop plants that can survive on less water has been a goal of plant scientists for awhile. Drought is a major cause of crop losses worldwide. Dry spells at different growth stages of the crop affect and limit growth and plant development, resulting in reduced yield. The frequency and intensity of droughts are expected to worsen as global temperatures rise.

close up of young nodal roots in soil

The project will focus on young nodal roots in the first 15 cm of soil. (Image courtesy of Kara J. Riggs and Robert Sharp)

“With a world population that is expected to top 9.7 billion by 2050, there is a vital need for crops better equipped to withstand water shortages and produce food with less water,” says Braun.

For his part of the project, Braun will be studying how plants shift their carbohydrate resources to the nodal roots in response to drought.

“We know that, upon drought, the leaves and the shoots stop growing and more carbon is allocated down to the roots to allow them to grow to hopefully explore more soil to find water. My lab wants to better understand how this process occurs and is controlled,” he says.

In addition to research, the project will provide interdisciplinary training for undergraduate and graduate students in the latest omics methods. It also will include training in science communication, which will be conducted in partnership with the MU School of Journalism.

Braun emphasizes the collaborative nature of the project and culture within the Interdisciplinary Plant Group at MU: “This is not a one-person effort, but rather the culmination of 30 years of scientists from multiple departments conducting research together through the Interdisciplinary Plant Group.”

The principal investigator of the project is Robert Sharp, a professor in the Division of Plant Sciences and director of the Interdisciplinary Plant Group. Other members of the scientific team are Felix B. Fritschi, an associate professor in the Division of Plant Sciences in the College of Agriculture, Food and Natural Resources; Trupti Joshi, an assistant research professor and director of translational bioinformatics in the Department of Molecular Microbiology and Immunology in the School of Medicine; Scott C. Peck, an associate professor in the Division of Biochemistry in the College of Agriculture, Food and Natural Resources and an investigator in the Bond Life Sciences Center; Jonathan T. Stemmle, an associate professor of strategic communication in the School of Journalism; and Melvin J. Oliver, an adjunct professor in the Division of Plant Sciences and a supervisory research geneticist with the USDA Agricultural Research Service. All of the investigators are members of the Interdisciplinary Plant Group.

An abstract of the project, titled “Physiological Genomics of Maize Nodal Root Growth under Drought”, is available on the NSF Web site.

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Written by: Melody Kroll

Related research strengths:
Development, Genetics & Genomics, Plant Biology