Fig. 7: A proposed model of ZmSnRK2.10-mediated natural variation in salt tolerance in maize.

Under salt stress, the kinase activity ZmSnRK2.10 and ZmSnRK2.9 is activated, they then interact with and phosphorylate ZmHAK4 at the Ser5 site, increasing the Na⁺ transport activity of ZmHAK4, which then facilitates the retrieval of Na⁺ from the xylem vessels, thereby promoting shoot Na⁺ exclusion and salt tolerance. In the salt-sensitive haplotype (with Del-356), a 20-bp deletion in ZmSnRK2.10 promoter reduces its transcript levels and leads to insufficient activation of ZmHAK4 in response to salt stress, compromising the ZmHAK4-mediated exclusion of Na⁺ from the shoot tissue. Source data are provided as a Source Data file.