TaNRT1.1B-mediated nitrogen acquisition contributes to salt adaptation and yield-trait maintenance in wheat

Abstract

Soil salinity is a major environmental stress that limits global wheat production, in part by impairing nitrogen acquisition, which integrates essential nutrient supply with stress-adaptation signaling. Although nitrogen fertilization can alleviate salt stress, the underlying molecular mechanisms remain largely unknown. Here, we show that salt stress suppresses nitrate accumulation in wheat seedlings, as well as reducing root and shoot growth. Comparative transcriptome profiling reveals that nitrate-associated genes and transcriptional regulators are significantly enriched among salt-responsive genes. To explore the functional relevance of this enrichment, we focused on TaNRT1.1B, a prominently downregulated nitrate transporter gene, demonstrating its role as a key regulator linking nitrate acquisition and salt-stress responses. Disruption of TaNRT1.1B reduced nitrate uptake, impaired ABA responses, compromised salt tolerance, and significantly reduced the values of yield-related traits under salt stress. Supporting the functional relevance of TaNRT1.1B, salt-tolerant wheat accessions had significantly higher TaNRT1.1B expression and nitrate levels under saline conditions than salt-sensitive lines. Collectively, our results demonstrate that TaNRT1.1B links nitrate uptake with salt-stress tolerance to coordinate growth and stress resilience in wheat, providing a potential genetic target for breeding of varieties with improved salt tolerance, nitrogen use efficiency, and grain yield.