Alkaline tolerance in plants: The AT1 gene and beyond

Salt stress poses a serious challenge to crop production and a significant threat to global food security and ecosystem sustainability. Soil salinization commonly occurs in conjunction with alkalization, which causes combined saline-alkaline stress. Alkaline soil predominantly comprises NaHCO₃ and Na₂CO₃ and is characterized by a high pH. The combined saline-alkaline stress is more harmful to crop production than neutral salt stress owing to the effects of both elevated salinity and high pH stress. Through genome association analysis of sorghum, a recent study has identified Alkaline tolerance 1 (AT1) as a contributor to alkaline sensitivity in crops. AT1, which is the first gene to be identified as being specifically associated with alkaline tolerance, encodes a G protein γ-subunit (Gγ). Editing of AT1 enhances the yields of sorghum, rice, maize, and millet grown in alkaline soils, indicating that AT1 has potential for generating alkaline-resistant crops. In this review, we summarize the role of AT1 in alkaline tolerance in plants and present a phylogenetic analysis along with a motif comparison of Gγ subunits of monocot and dicot plants across various species.