Hormonal regulation of plant primary metabolism under drought.

Phytohormones are essential signaling molecules globally regulating many processes of plants, including their growth, development and stress responses. The promotion of growth and the enhancement of stress resistance have to be balanced, especially under adverse conditions such as drought stress, because of limited resources. Plants cope with drought stress via various strategies, including the transcriptional regulation of stress-responsive genes and the adjustment of metabolism, and phytohormones play roles in these processes. However, besides abscisic acid (ABA) is an important signal under drought, less attention has been paid to other phytohormones. In this review, we summarize progress in the understanding of phytohormone-regulated primary metabolism under water-limited conditions, especially in Arabidopsis thaliana, and highlight recent findings concerning the amino acids associated with ABA metabolism and signaling. We also discuss how phytohormones function antagonistically and synergistically in order to balance growth and stress responses.