High expression of S-type anion channels optimizes stomatal dynamics for improved water conservation in Coix lacryma-jobi

Stomatal regulation plays a vital role in enhancing drought resistance in plants, yet the underlying molecular mechanisms in C4 crops remain largely unexplored. Focusing on the nutritionally important C4 species Coix lacryma-jobi, we identified key anion transporters—ClSLAC1, ClSLAH3, and ClALMT12—with elevated leaf expression, notably higher for ClSLAC1 and ClSLAH3 than ClALMT12. Utilizing computational modeling with OnGuard, we predicted that increased expression of ClSLACs promote stomatal opening and closing. Experimental validation further revealed that Coix has both faster stomatal kinetics and reduced stomatal aperture relative to Arabidopsis. Our findings indicate that enhanced ClSLAC1/ClSLAH3 expression significantly improves water retention of Coix, providing a molecular foundation for the water use. These insights could pave the way for developing stress-resilient crops through targeted engineering strategies.