Gain-of-function variants of cytokinin receptors ($)

Arabidopsis has three membrane-located, histidine-kinase cytokinin (CK) receptors (AHK2, 3, and 4). Loss-of-function mutants suggest that AHK2 and AHK3 function somewhat redundantly. To further explore the roles of these receptors, Bartrina and Jensen et al. isolated dominant gain-of-function mutants, repressor of cytokinin deficiency2 (rock2) and rock3. As expected, these GoF mutants show enhanced CK signaling and sensitivity. Developmental phenotypes include an enhancement of shoot growth, delay in leaf senescence, and suppression of root growth. This study provides insights into CK receptor structure and function, as well as insights into the consequence of localized increases of CK sensitivity. Plant Physiol. 10.1104/pp.16.01903