A Gγ protein regulates alkaline sensitivity in crops

Huili Zhang, Feifei Yu, Peng Xie, Shengyuan Sun, Xinhua Qiao, Sanyuan Tang, Chengxuan Chen, Sen Yang, Cuo Mei, Dekai Yang, Yaorong Wu, Ran Xia, Xu Li, Jun Lu, Yuxi Liu, Xiaowei Xie, Dongmei Ma, Xing Xu, Zhengwei Liang, Zhonghui Feng, Xiahe Huang, Hong Yu ¹, Guifu Liu, Yingchun Wang, Jiayang Li , Qifa Zhang, Chang Chen, Yidan Ouyang, Qi Xie

Science; 2023 Mar 24; 379(6638):eade8416. doi: 10.1126/science.ade8416. 

Abstract

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, Alkaline Tolerance 1 (AT1), specifically related to alkaline-salinity sensitivity. An at1 allele with a carboxyl-terminal truncation increased sensitivity, whereas knockout of AT1 increased tolerance to alkalinity in sorghum, millet, rice, and maize. AT1 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 AT1 homologs or selecting its natural nonfunctional alleles could improve crop productivity in sodic lands.

See https://pubmed.ncbi.nlm.nih.gov/36952416/

Figure: Genetic modification of AT1 enhances alkaline stress tolerance.

The Gγ subunit, AT1, pairs with Gβ to negatively modulate the phosphorylation level of PIP2 aquaporins. Thus, AT1 reduces the H₂O₂ export activity of PIP2s, leading to the overaccumulation of H₂O₂ and resulting in alkaline stress sensitivity. By contrast, the artificial or natural knockouts of AT1 homologs release the inhibition of PIP2s by AT1 in crops and have improved survival rates and yield under alkaline stress. [Figure created using BioRender].