Synthetic ion channel inhibitors enhance plant drought tolerance.

Abstract

Drought stress significantly threatens global food security. According to the FAO2024, agriculture absorbs up to 80% of drought impacts. Stomata are vital pores for gas exchange and transpiration in plants. Stomatal closure, which is crucial for drought tolerance, is regulated by ion transport systems. Here, we identify two inhibitors of plasma membrane voltage-dependent potassium (K⁺) channels, NS5806 and UA49, that induce stomatal closure, reduce guard cell K⁺ levels, and increase drought resistance in Arabidopsis plants. This chemical-induced stomatal closure pathway is distinct from the abscisic acid (ABA). Notably, K⁺ channel inhibition led to increased cytosolic Ca²⁺, which was absent in K⁺ inward channel mutants, highlighting the link between K⁺ channel activity and cytosolic Ca²⁺ elevation. These findings suggest that the chemical regulation of K⁺ channels represents a strategy to induce stomatal closure, potentially improving plant drought tolerance through targeted interventions.