Plants' "Survival Wisdom": How a Single Protein Balances Nutrition and Stress Resistance

                        Plants' "Survival Wisdom": How a Single Protein Balances Nutrition and Stress Resistance

Source: Chu, C., Hu, B., Gong, X., et al. (2025). NRT1.1B functions as a dual receptor for nitrate and ABA to coordinate nutrient acquisition and stress response in plants. Cell. https://doi.org/10.1016/j.cell.2025.07.027

Abstract: A groundbreaking study published in Cell reveals the "survival wisdom" of plants in coping with multiple stresses. Researchers from South China Agricultural University identified that the protein NRT1.1B acts as a "smart switch," simultaneously sensing soil nitrogen (nutrient) and drought signals (stress) to help plants make optimal survival choices. This dual-function receptor prioritizes stress resistance under low nitrogen conditions by binding to abscisic acid (ABA)—a key stress hormone—while focusing on growth when nitrogen is abundant. The discovery, conserved across major crops like rice, wheat, and maize, offers a critical target for developing resource-efficient, stress-tolerant crop varieties, advancing sustainable agriculture.

Content:

When faced with hunger and adversity, plants have evolved remarkable "survival wisdom" to balance nutrient acquisition and stress resistance. A landmark study published on August 11 in Cell by Professor Chengcai Chu’s team from South China Agricultural University unveils the molecular mechanism behind this ability: a protein called NRT1.1B that acts as a dual sensor for both nutrients and stress signals.

Navigating the Complexity of Nature

Plants constantly battle a mix of challenges—drought, nutrient scarcity, and extreme weather—often simultaneously. For example, drought typically coincides with limited soil nitrogen, a vital nutrient for growth. Understanding how plants integrate these signals is key to developing resilient, high-yield crops, especially as climate change intensifies stressors and over-fertilization harms the environment.

Previous research focused on single signals: abscisic acid (ABA), known as a "stress alarm" that triggers drought resistance, and NRT1 Proteins, which act as "nutrient detectors" for nitrogen. However, how these systems interact remained a mystery—until now.

NRT1.1B: More Than a Nutrient Detector

The team focused on NRT1.1B, a critical nitrogen-sensing protein in rice. By simulating natural low-nitrogen conditions (unlike previous lab studies using high nitrogen levels), they made a surprising discovery: NRT1.1B also binds directly to ABA, functioning as a dual receptor.

In low-nitrogen environments, rice exhibited a strong ABA response, activating numerous stress-resistant genes. In high-nitrogen conditions, this response was suppressed by over 70%. "Plants adjust their stress sensitivity based on nutrient availability," explains co-corresponding author Bin Hu.

Remarkably, NRT1.1B binds ABA 1,000 times more strongly than it binds nitrogen. This means when nitrogen is scarce, the protein prioritizes ABA signals, shifting the plant into "survival mode" to resist stress. When nitrogen is abundant, it focuses on growth.

A Complete Signal Chain

The researchers mapped a full "signal 传导链 (signal transduction chain)" linking perception to action. Under low nitrogen, NRT1.1B binds ABA and recruits a protein called SPX4, which normally blocks a "messenger" protein, NLP4. With SPX4 diverted, NLP4 enters the nucleus, activating stress-resistance genes.

This mechanism is conserved across plants—arabidopsis, maize, and wheat share similar dual-function Proteins—indicating it’s an ancient evolutionary adaptation.

Implications for Sustainable Agriculture

Field trials showed that NRT1.1B helps rice maintain yields under low nitrogen and drought, highlighting its potential for crop improvement. "Modifying NRT1.1B could lead to varieties that thrive with less fertilizer and water," notes academician Jiayang Li, emphasizing its role in developing "resource-efficient" crops.

This research redefines our understanding of plant stress sensing, breaking the previous belief that ABA is only detected inside cells. As co-corresponding author Xin Gong states, "It’s a leap in understanding how plants navigate complex environments."

By harnessing this "survival wisdom," scientists aim to breed crops that balance growth and resilience, paving the way for greener, more sustainable agriculture in a changing climate.