Antagonistic action of ABA and cytokinin signaling mediates drought stress response in Arabidopsis ($) (Mol Plant)

Drought stress results in a conglomeration of hormone pathways that interact to coordinate plant growth and stress response. ABA and cytokinin signaling are known to be antagonistic but it is unclear how these two pathways are connected. Huang et al. identified roles for several ARR proteins, negative regulators in cytokinin signaling, in the ABA pathway. Specifically, ABA promoting kinases, SnRK2s, were found to phosphorylate ARR5, promoting ARR5 stability and enhancing cytokinin inhibition and enhancing ABA signaling. Meanwhile, ARR1,11,12 inhibit SnRK2s to downregulate ABA signaling. These data show a model in which there is crosstalk between ABA and cytokinin signaling components. (Summary by Alecia Biel) Mol. Plant 10.1016/j.molp.2018.05.001.