Abstract

Cytokinins are essential plant hormones that regulate numerous developmental processes, and their perception is mediated by a family of histidine kinase receptors. The subcellular localization of these receptors is critical for signal transduction, with some known to reside at the plasma membrane and others at the endoplasmic reticulum (ER). This study investigates the subcellular distribution of cytokinin receptors in potato (*Solanum tuberosum*), a globally important crop. Using a combination of cell fractionation, immunolocalization techniques, and confocal microscopy, we provide compelling evidence for the **preferential localization** of specific potato cytokinin receptor isoforms within the ER membrane system. Our findings indicate that a significant pool of these receptors is not restricted to the plasma membrane, suggesting a dual perception system or a distinct role for ER-localized receptors in mediating cytokinin signaling, possibly through interaction with ER-resident components or by regulating receptor turnover. This discovery is vital for understanding the complexity of cytokinin signal transduction in potato and offers a new target for genetic engineering aimed at improving crop yield and stress tolerance.