Cytokinin: perception,signal transduction,and role in plant growth and development

Cytokinins are essential hormones for the proper growth and development of plants. They exert their actions through the phosphorylation of two-component signaling factors. The two-component elements in cytokinin signaling display not only overlapping, but also specific functions throughout a life cycle. These elements regulate the development of shoots, roots, and inflorescence meristems inArabidopsis; shoot meristems in rice; and nodule formation in the lotus. They are also involved in interactions between plants and pathogens. In this review, we examine the mechanism for signaling events initiated by cytokinins inArabidopsis.