Figure 11.

A Working Model for OsPM1 Function under Drought Stress.

Under drought stress, the transcription factor OsbZIP46 is activated by phosphorylation, which then activates the expression of OsPM1. OsPM1 protein allows ABA influx, which amplifies and enhances ABA signaling in a very short time, including the transcriptional upregulation of OsbZIP46 and many other ABA signaling pathway genes. MODD protein may be necessary to interrupt the feedback loop between OsbZIP46 and OsPM1. In addition, the initial ABA influx is mediated by low level of OsPM1 or other unknown ABA transporters at the plasma membrane, and other transcription factors besides OsbZIP46 may also regulate the expression of OsPM1 under drought stress. Arrowheads indicate positive regulation. Question marks represent presumed pathways.