Figure 2.

SA and ROS Are the Hubs that Integrate Regulatory Signals from Plant Hormone Pathways to Control Leaf Senescence and Plant Immunity. Cross-talks between SA/ROS and other hormones are mainly modulated by key components in their signaling pathways. The SA-dependent responses are suppressed by JA, ET, and ABA via repressing SA-related genes such as biosynthesis gene ICS1. Auxin and BRs also antagonize SA signaling pathway. Additionally, GA and CK mainly synergistically interact with SA. Meanwhile, besides Auxin, ET, JA, ABA, GA, CK, and BR can contribute positively to ROS responses. SA can trigger the accumulation of ROS, and vice versa. Abbreviations: ET, ethylene; JA, jasmonic acid; ABA, abscisic acid; GA, gibberellin; CK, Cytokinin; BR, Brassinosteroid.