The Role of Cytokinins in Plant Under Salt Stress

The plant hormone cytokinins (CKs) were generally considered associated with plant development. More recently, functions of CKs in plant stress defense including salt have been increasingly characterized. Under saline conditions, not only CKs homeostasis but also its signal transduction pathway is disturbed in a plant species-dependent manner. In turn, through manipulating exogenous CKs application or endogenous CKs metabolism or signaling, plant behavior can also be diverse across species. In this review, we systematically summarized this mutual regulation between CKs and salt stress. Considering the senescence-delaying effect of CKs, its roles in mitigating salt-induced senescence and maintaining crop yields are specifically highlighted. We also discussed here how CKs crosstalk with other phytohormones, including ABA and ethylene, to mediate salt response. In sum, this review provides a comprehensive integration of current knowledge on the regulatory role of CKs upon salt stress and puts forward research directions for future studies.