AN international team of scientists aims to lessen the agriculture industry's reliance on nitrogen fertilizers by helping soybeans and similar plants boost their nitrogen production, even in areas with traditionally poor soil quality.
Researchers from the Technical University of Madrid's (UPM) Center of Plant Genomics & Biotechnology and the Advanced Photon Source (APS) at the U.S. Department of Energy's Argonne National Laboratory used X-ray analysis to map a path to increasing the amount of nitrogen legumes deposit into the soil, according to a release from Argonne.
Cultivating legumes is one of the main ways farmers add natural nitrogen to their fields. Legumes use iron in the soil to carry out a complex chemical process called nitrogen fixation, which collects atmospheric nitrogen and converts it into organic forms that help the plant grow. When the plant dies, the excess nitrogen is released back into to the soil to help the next crop.
Often, though, legumes are grown in areas with iron-depleted soil, which limits their nitrogen fixation.
The Argonne-UPM team has created the first-ever model of how iron is transported in the plant's root nodule to trigger nitrogen fixation, the news release noted. This is the first step in modifying the plants to maximize iron use.
The team used high-energy X-rays from APS to track the distribution of minute amounts of iron in the different developmental regions of rhizobia-containing roots. The X-rays provided a high sensitivity to elements and a high spatial resolution.
"The long-term goal is to help sustainable agriculture practices and further diminish the environmental damage from overuse of nitrogen fertilizers," said UPM's Manuel Gonzalez-Guerrero, lead author of the paper. "This can be done by maximizing the delivery of essential metal oligonutrients to nitrogen-fixing rhizobia."
In future studies, he hopes to identify and characterize the key biological proteins responsible for iron transportation, which would give researchers targets to manipulate and screen for new legume varieties with increased nitrogen-fixation capabilities and higher nutritional value.
Full details can be found in "Iron Distribution through the Developmental Stages of Medicago Truncatula Nodules," at http://pubs.rsc.org/en/content/articlelanding/2013/MT/C3MT00060E.