A Gγ protein regulates alkaline sensitivity in crops

The use of alkaline salt lands for crop production is hindered by a scarcity of knowledge and breeding efforts for plant alkaline tolerance. Through genome association analysis of sorghum, a naturally high-alkaline-tolerant crop, we detected a major locus, <i>Alkaline Tolerance 1</i> (<i>AT1</i>), specifically related to alkaline-salinity sensitivity. An <i>at1</i> allele with a carboxyl-terminal truncation increased sensitivity, whereas knockout of <i>AT1</i> increased tolerance to alkalinity in sorghum, millet, rice, and maize. <i>AT1</i> encodes an atypical G protein γ subunit that affects the phosphorylation of aquaporins to modulate the distribution of hydrogen peroxide (H₂O₂)_. These processes appear to protect plants against oxidative stress by alkali. Designing knockouts of <i>AT1</i> homologs or selecting its natural nonfunctional alleles could improve crop productivity in sodic lands.