The 30th International Conference on Arabidopsis Research (ICAR 2019)

609 / 2019-04-23 10:04:36

GSK3-like kinases are a class of positive components in the core ABA signaling

ABA,BR

Plenary track > Abiotic Stress

The phytohormone abscisic acid (ABA) acts not only as a protector to respond to inclement environments, but also as a key player to regulate plant growth and development. A canonical ABA signaling pathway had been established. However, several studies have provided direct evidence to support that the full kinase activation of SnRK2.2 and SnRK2.3 requires phosphorylation by other kinases. We found that BIN2, a member of GSK3-like kinases, acts downstream of ABA receptors and upstream of SnRK2s to directly phosphorylate and activate SnRK2.2 and SnRK2.3. ABI1 and ABI2, can interact with and dephosporylate BIN2 to inhibit its kinase activity with an ABA dependent manner. Therefore, we propose a significantly updated model by adding BIN2 as positive components in the ABA primary signaling pathway. In addition, we also found that reactive oxygen species (ROS) can directly modify the cysteine residues of BIN2, to activate BIN2. We proposed that many stresses may directly activate GSK3s, which further enhance the activity of SnRK2s and mediate the crosstalk between ABA and other stress signaling.