RESOLVING THE LEDGER
This is one outlet's own report from Phys.org — the article as it was filed. Other outlets are covering the same event; open the full story to compare every source side by side.
See the full story · 1 sources
edited by Sadie Harley , reviewed by Andrew Zinin
This article has been reviewed according to Science X's editorial process and policies . Editors have highlighted the following attributes while ensuring the content's credibility:
Add as preferred source Certain plants, including legumes, form specialized organs called root nodules, where they establish symbiotic relationships with nitrogen-fixing bacteria. This root nodule symbiosis enables plants to use atmospheric nitrogen for growth, reducing their dependence on nitrogen fertilizers. Applying this characteristic is highly promising for developing sustainable agricultural systems.
Conversely, legumes suppress root nodule formation when sufficient nitrate and other nitrogen nutrients are present in the soil. Biological nitrogen fixation requires substantial energy. Thus, this response is thought to enable plants to balance the costs and benefits of symbiosis according to nitrogen availability. However, the molecular mechanisms by which plants monitor their internal nitrogen status and regulate nodulation have not been fully elucidated.
In this study, researchers at University of Tsukuba investigated the function of nitrate reductase (NIA) in the model legume Lotus japonicus. They discovered that NIA serves not only as a key enzyme in nitrogen assimilation, catalyzing the first step of nitrate reduction, but also as an important regulator of nitrate-responsive nodulation by maintaining appropriate internal nitrate levels.
The study is published in the journal Plant and Cell Physiology .
Furthermore, the researchers found that loss of NIA function resulted in excessive nitrate accumulation within the plant, strongly suppressing root nodule formation even under low-nitrate conditions that would not affect nodulation. These findings indicate that the plant's internal nitrate status, rather than external nitrate availability alone, is critical for determining nodulation responses.
This study uncovers a previously unrecognized role of NIA in controlling root nodule formation by regulating internal nitrate status, in addition to its well-established role in nitrogen assimilation. These findings offer new insights into the mechanisms regulating root nodule symbiosis and may contribute to the development of sustainable agricultural technologies aimed at optimizing nodulation to reduce reliance on nitrogen fertilizers.
Momoyo Ito et al, Nitrate Reductase Modulates Internal Nitrate Status and Nodulation Responses to Nitrate in Lotus japonicus , Plant and Cell Physiology (2026). DOI: 10.1093/pcp/pcag108
Journal information: Plant and Cell Physiology
BSc Life Sciences & Ecology. Microbiology lab background with pharmaceutical news experience in oil, gas, and renewable industries. Full profile →
Master's in physics with research experience. Long-time science news enthusiast. Plays key role in Science X's editorial success. Full profile →
AIPROPX is an independent multi-source news index — we track, compare, and connect coverage from across the web into one place you won't find anywhere else.