A research team led by Prof. LIU Binmei from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences has identified an important gene, GLR2, which regulates rice's resistance to the herbicide glufosinate and enhances salt stress tolerance through its role in downstream gene regulation. 

Their findings were published in Plant Physiology.

Glufosinate is a widely used, broad-spectrum herbicide praised for its environmental friendliness and effectiveness. However, little is known about endogenous genes in rice that confer glufosinate resistance. 

The team had previously created two rice mutants, glr1 and glr2, that exhibit resistance to the herbicide glufosinate. In their new study, they focuses on glr2 mutant and its connection to the GLR1 gene.

Their study found that the GLR2 gene encodes a transcription factor whose expression is significantly induced by glufosinate treatment. This transcription factor binds directly to the promoter of the GLR1 gene, boosting its expression. GLR1, in turn, regulates the downstream gene GS1, which plays a critical role in glufosinate resistance.

The study also revealed that GLR2 and GLR1 interact at the protein level, amplifying the plant's ability to resist herbicide-induced stress.

Further experiments demonstrated that GLR2 activity influences physiological traits beyond herbicide resistance. Notably, GLR2 plays a critical role in modulating salt tolerance. The glr2 mutant exhibited strong growth and survival under high salinity conditions, significantly outperforming wild-type rice.

Molecular analysis confirmed that the absence of GLR2 disrupts this regulatory cascade, underscoring its importance in adaptive responses to abiotic stresses.

"It proved that that the GLR2-GLR1 module plays a critical role in enhancing both herbicide resistance and stress adaptation in rice," said Dr. YE Yafeng, a member of the team.

This breakthrough provides valuable genetic resources for developing rice varieties capable of thriving in adverse environments, such as saline soils. "By leveraging this module, we can contribute to better land utilization and improved crop resilience, which are crucial for addressing agricultural challenges in the face of climate change and limited arable land," said Dr. YE.

Model of GLR2 Function: Molecular Mechanism Regulating Glufosinate Resistance and Stress Adaptation in Rice (Image by YE Yafeng)