The Sensor Histidine Kinases AHK2 and AHK3 Proceed into Multiple Serine/Threonine/Tyrosine Phosphorylation Pathways in Arabidopsis thaliana

Cytokinins are N6-substituted adenine derivatives that are involved in the regulation of numerous aspects of plant growth and development. These include the control of cell division, leaf senescence, apical dominance, sink/source relationship, vascular and embryonic development, and apical meristem activity (Kieber and Schaller, 2014). In addition, there is increasing evidence for the function of cytokinins in abiotic stress responses (Zwack and Rashotte, 2015).