Synergistic and antagonistic pleiotropy of STOP1 in stress tolerance

SENSITIVE TO PROTON RHIZOTOXICITY 1 (STOP1) isa master transcription factor (TF) that regulates genes encoding proteins critical for cellular pH homeostasis. STOP1 also causes pleiotropic effects in both roots and shoots associated with various stress tolerances. STOP1-regulated genes in roots synergistically confer tolerance to coexisting stress factors in acid soil, and root-architecture remodeling for superior phosphorus acquisition. Additionally, STOP1 confers salt tolerance to roots under low-potassium conditions. By contrast, STOP1 antagonistically func-tions in shoots to promote hypoxia tolerance but to suppress drought tolerance. In this review, we discuss how these synergetic-and antagonistic-pleiotropic effects indicate that STOP1 isa central hub of stress regulation and that the harmo-nization of STOP1-regulated traits is essential for plant adaptation to various environments.