Genetic variants help plants adapt to nitrogen deficiency

By studying over 220 different wheat and barley varieties from over half a century of plant breeding, a team of researchers from the University of Bonn has discovered genetic variants in these crops that help improve nitrogen utilization. 

“We studied a large number of wheat and barley genotypes under different nitrogen supply conditions and analyzed their root architecture and nitrogen accumulation in the plants,” said study lead author Md. Nurealam Sidiqqui, an expert in Biochemistry and Molecular Biology at Bonn.

At the University of Bonn’s agricultural research campus Klein-Altendorf, the experts studied these different varieties on plots with both high and low nitrogen levels and, for each variety, analyzed root trait characteristics and the nitrogen content of leaves and grains, while performing genetic analyses to find links between DNA sequences and various traits.

The investigations revealed that certain variants of a specific gene called NPF2.12 caused plants to develop larger root systems when facing deficiencies in soil nitrogen supply.

“It is likely that the gene, or rather the protein it encodes, acts as a sensor that needs to be switched off when nitrogen levels in the soil are low in order to indirectly increase the messenger nitric oxide as part of a signaling cascade, which in turn induces root growth, thereby improving nitrogen utilization,” explained senior author Agim Ballvora, an expert in Plant Breeding and Biotechnology at Bonn.

“Under low nitrogen conditions and in the presence of certain variants of the NPF2.12 gene, increased nitrogen content in leaves and grains is detectable compared to high nitrogen availability.” 

By analyzing wheat plants with a defect in the NPF2.12 gene, the scientists discovered that, when nitrogen supply was poor, these plants behaved like cultivars inherently possessing this helpful genetic variant.

“These results show that NPF2.12 is a negative regulator, whose reduced expression in corresponding cultivars results in more root growth and higher nitrogen content in the shoot through a sophisticated mechanism,” said co-author Gabriel Schaaf, a professor of Plant Nutrition at the same university.

In the future, a better understanding of the genetic and molecular function of nitrogen sensing could accelerate the breeding of varieties with improved efficiency.

The study is published in the journal New Phytologist.

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By Andrei Ionescu, Earth.com Staff Writer

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