Review. Going beyond the model: When different plants have different plans

In a recent review, Nieves-Cordones and Rubio highlight the species-specific strategies used by Arabidopsis and crop plants to regulate potassium (K⁺) and sodium (Na⁺) transport, which challenges the universality of Arabidopsis thaliana research. In Arabidopsis, K⁺ uptake is largely mediated by AKT1-type voltage-gated channels, whereas crops like rice and tomato rely more heavily on HAK5-type K⁺/H⁺ symporters, particularly under low external K⁺ conditions. These differences are likely shaped by variations in membrane potential, metabolic cost, and evolutionary context. Notably, crops possess clade IV HAK transporters—absent in Arabidopsis—that facilitate Na⁺ retrieval from the xylem and contribute to salt tolerance, especially in vascular tissues. In reproductive organs, HAK5-like transporters are essential for pollen viability and fertility in tomato and rice, with mutations leading to reduced seed set or even parthenocarpy, highlighting their agronomic relevance. The study also uncovers species-specific rewiring of Ca²⁺-dependent CBL-CIPK signaling networks, with tomato and rice exhibiting regulatory controls that are either absent or divergent in Arabidopsis. Taken together, these findings underscore the limitations of extrapolating from Arabidopsis alone and advocate for broader comparative studies to uncover the diversity of ion transport solutions evolved across plant lineages. (Summary by Stephanie Temnyk @STemnyk) Trends in Plant Science 10.1016/j.tplants.2025.05.007