Xiang Lu, Yuqi He, Wenfeng Weng, Zebin Liu, Yuanfen Gao, Yaliang Shi, Wei Li, Dili Lai, Mengyu Zhao, Rintu Jha, Hui Zhao, Guangsheng Li, Chaonan Guan, Shuai Shao, Jingjun Ruan, Sun Hee Woo, Yinan Ouyang, Muriel Quinet, Milen I. Georgiev, Alisdair R. Fernie, Congcong Hou, Kaixuan Zhang, Xu Liu, Meiliang Zhou

Advanced Science; 2025; IF: 14.1

DOI:10.1002/advs.202511570

Abstract

Globally, soil salinization increasingly affects farmland, severely limiting the production of Tartary buckwheat (Fagopyrum tataricum). To identify genetic factors for salt tolerance, we analyzed core Tartary buckwheat accessions and utilized differential expression analysis and genome-wide association studies (GWAS), identifying a key domesticated magnesium transporter protein, FtMGT2. A single nucleotide polymorphism (SNP) genotype (G/A) of a natural variant located in the FtMGT2 promoter was found to be positively associated with the expression of FtMGT2 and salt tolerance variation. Mechanistically, the MADS transcription factor FtAGL16 binds the A variant more strongly. FtAGL16 and the MYB transcription factor FtMYB15L co-regulate FtMGT2 transcription, with FtMYB15L protein stability strictly controlled by the E3 ubiquitin ligase FtBRG1. Intriguingly, under salt stress, FtAGL16 can compete with FtBRG1 for binding to FtMYB15L, stabilizing and accumulating FtMYB15L. This enhances FtMGT2 expression, increasing Mg2+ flux, which in turn enhances the transport activity of the sodium (Na+) transporter FtHKT1. This coordinated action leads to increased Na+ efflux and enhanced salt resistance. This study thereby establishes both the theoretical basis and practical application for targeted molecular breeding to enhance plant salt tolerance.