Redefining the role of sodium exclusion within salt tolerance
Sebastian Garcia‐Daga, Stuart J. Roy, Matthew Gilliham
Abstract
Salt contamination of soils and irrigation water is a significant environmental concern for crop production. Leaf sodium (Na + ) exclusion is commonly proposed to be a key subtrait of salt tolerance for many crop plants. High-Affinity Potassium (K + ) Transporter 1 (HKT1) proteins have previously been identified as major controllers of leaf Na + exclusion across diverse species. However, leaf Na + exclusion does not always correlate with salt tolerance. We discuss literature which shows leaf Na + accumulation can, in some circumstances, be tolerated without a detrimental effect on yield when HKT1 still functions to exclude Na + from reproductive tissues. We conclude that, by having an ultimate role in the protection of reproductive performance, HKT1s' role in adaptation to salinity warrants redefinition.