Plant signaling pathways involved in stomatal movement under drought stress conditions

Governed by environmental stimuli and internal signaling cascades, stomatal movement determines water use efficiency and CO2 assimilation for photosynthesis under normal and stressful conditions, most importantly under water scarcity. Manipulation of these signaling pathways is one way to optimize plant resilience/tolerance and performance under constantly changing environment. Oscillations and interactions between the internal and environmental cues make it difficult to determine the consequence of these signals. After drought stress perception, the activated molecules initiate the generation of redox, hormone, and chemical signals, the interactions of which control stomatal responses. Second messengers, proteins, and intermediate chemicals then react with these signaling molecules to positively or negatively transmit these signals through a series of molecular events. This review is aimed to discuss the step-by-step scheme of these signaling pathways to provide insight into these molecular events andtoincentivize further studies on their unknown aspects for improved stomatal responses under various environmental conditions, particularly stress conditions, and specifically drought stress.