Understanding how plants metabolize nutrients to improve farming, protect the environment

Hideki Takahashi, an associate professor in the MSU Department of Biochemistry and Molecular Biology, is working to understand the molecular mechanisms plants use to metabolize nutrients.

Hideki Takahashi uses Arabidopsis to understand how plants metabolize nutrients.
Hideki Takahashi uses Arabidopsis to understand how plants metabolize nutrients.

Hideki TakahashiDelivering the right amount of nutrients to promote healthy growth of crops is a battle constantly waged by farmers worldwide. And as the global population increases and more demand for food production is placed on land, soil quality is declining.

According to the United Nations, more than a third of the planet’s soil is severely degraded from agriculture, and that number is only expected to rise.

For farmers in developing countries, manure and crop residues are organic options, but synthetic fertilizers are expensive and often inaccessible. In the U.S., blanket application of fertilizers can sometimes be insufficient and other times wasteful, causing environmental issues. To make matters worse, climate change is accelerating environmental deterioration.

Hideki Takahashi, an associate professor in the Michigan State University Department of Biochemistry and Molecular Biology, is working to understand the molecular mechanisms plants use to metabolize these nutrients.

He is particularly interested in nitrogen and sulfur, two nutrients essential to the healthy development of plants and seeds. His goals include uncovering how plants take in nutrition and use it, and determining how to enhance that process.

Takahashi said more than 100 million tons of nitrogen fertilizers are applied annually to agricultural fields. Anywhere from 50% to 70% goes unused by crops and enters the environment through aquatic avenues such as rivers and oceans or is emitted as a greenhouse gas, nitrous oxide, to the atmosphere.

According to the Global Partnership on Nutrient Management, synthetic nitrogen is being deployed globally at twice the rate of organic sources — manure, crop residues and leguminous crops that fix nitrogen. This excess nitrogen can pollute drinking water or cause harmful algal blooms that devastate entire aquatic communities.

“While my work is heavily involved in the laboratory with basic science, the outcome can potentially help people all over the world,” Takahashi said. “If we can determine the specific mechanisms responsible for efficient nutrient metabolism, we can use both classical plant breeding and transgenic approaches to introduce those genes to plants that could benefit. If we can use less nitrogen fertilizer while achieving better agricultural results, that benefits everyone.”

Takahashi studies Arabidopsis, a model plant species, to see how they modify their root systems to absorb nutrients that are unevenly distributed throughout the soil. He’s found that in nitrogen-rich regions, lateral plant roots grow well, whereas in nitrogen-deficient regions there is little growth.

“This suggests that Arabidopsis plants have the ability to use their resources economically,” Takahashi said. “They won’t spend the energy to grow roots in areas they know aren’t fruitful, but if they detect nutrients, the roots will proliferate.”

Takahashi is investigating small signaling peptides, molecules that communicate to the plant to perform a particular task. With funding from the National Science Foundation, he has identified small signaling peptides that control the plant’s root growth.

Takahashi said the function of most of these molecules, however, remains a mystery. He has expressed interest in furthering this research with important food crops such as legumes, which are known nitrogen fixers.

“Small signaling peptides are a potential area of great discovery,” Takahashi said. “We know they are helping the plant make decisions on optimal growth and nutrient acquisition, so the outcome of this research can have a profound effect on strategies with genetic engineering of agriculturally relevant plants.”

This article was published in Futures, a magazine produced twice per year by Michigan State University AgBioResearch. To view past issues of Futures, visit www.futuresmagazine.msu.edu. For more information, email Holly Whetstone, editor, at whetst11@msu.edu or call 517-355-0123.

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