Figure 9.

Working model of OsbZIP23-mediated regulation of ABA signaling pathway under drought stress in rice. ABA, which is induced by drought stress, inhibits the activity of OsPP2C49 to release the kinase activity of SAPK2 for further activation of OsbZIP23 through phosphorylation. OsbZIP23 could directly bind to the promoters of OsPP2C49 and positively regulates the expression of OsPP2C49, which in turn negatively regulates the ABA signaling. Meanwhile, OsbZIP23 could positively affect the ABA levels through direct regulation of OsNCED4. In addition, OsbZIP23 also directly regulates diverse stress-related genes involved in the drought response and adaptation in rice (see details in Supplemental Fig. S6). Green arrows indicate protein-protein interaction, red arrows indicate direct binding by OsbZIP23, and gray arrows point to putative functions. P, Phosphorylation.