Link between Plant Phosphate and Drought Stress Responses.

The menace of drought has persistently loomed over global crop production, posing a serious threat to agricultural sustainability. Research on drought stress highlights the important role of the phytohormone abscisic acid (ABA) in orchestrating plant responses to drought conditions. ABA regulates various drought/dehydration-responsive genes, initiates stomatal closure, and influences cellular responses to drought stress. Additionally, plants employ a phosphate starvation response (PSR) mechanism to manage phosphate (Pi) deficiency, with ABA playing a role in its regulation. However, despite intensive research in these fields, the precise connection among PSRs, drought stress, and ABA signaling still needs to be determined. Recently, PSR-related gene induction has been reported to occur before the induction of ABA-responsive genes under progressive mild drought. Mild drought decreases Pi uptake and contents in plants, triggering PSRs, which play an important role in plant growth during mild drought. Both ABA-responsive and PSR-related gene expression could indicate plant perception of external moisture conditions. Thus, integrating the information regarding their associated gene expression with soil moisture contents and thermographic data can enable timely irrigation optimization to mitigate the effect of drought on crop productivity.