Rice NIN-LIKE PROTEIN 4 plays a pivotal role in nitrogen use efficiency.

Area of Science:

• Plant Biology
• Agricultural Science
• Molecular Genetics

Background:

• Nitrogen (N) is essential for rice growth, but excessive fertilizer use causes environmental issues.
• Improving Nitrogen Use Efficiency (NUE) is vital for sustainable rice production.
• Limited regulators are known to enhance NUE in rice.

Purpose of the Study:

• To investigate the role of rice NIN-like protein 4 (OsNLP4) in regulating rice NUE and yield.
• To identify OsNLP4 as a potential target for improving crop NUE.

Main Methods:

• Field trials were conducted to assess yield and NUE in OsNLP4 loss-of-function and overexpression rice lines.
• Transcriptomic analysis was used to understand the molecular mechanisms of OsNLP4.
• Arabidopsis nlp7 mutant complementation assays were performed.

Main Results:

• Loss of OsNLP4 function significantly reduced rice yield and NUE under various nitrogen conditions.
• OsNLP4 overexpression lines showed a 30% increase in yield and a 47% increase in NUE.
• OsNLP4 directly binds to nitrate-responsive cis-elements, regulating N uptake, assimilation, and signaling genes.
• OsNLP4 overexpression rescued the Arabidopsis nlp7 mutant phenotype.

Conclusions:

• OsNLP4 plays a critical role in regulating rice NUE and yield.
• OsNLP4 acts as a master regulator of nitrogen metabolism in rice.
• OsNLP4 is a promising target for genetic engineering to enhance NUE in crops.