Fig. 7
Model proposed for the subnetwork WRKY18/WRKY25/WRKY53 under the influence of an oxidative signal to induce senescence through WRKY53. The equilibrium of WRKY18/WRKY25/WRKY53 network encounters modifications at the onset of senescence. WRKY25 senses increasing H2O2 contents, and the oxidized form is less efficient in DNA-binding and upregulation of WRKY53 expression. However, at the same time, increasing H2O2 contents lead to increasing WRKY25 expression, so that the WRKY25/WRKY18 heterodimer forms, mitigating WRKY18’s repressive effect on WRKY53 expression and increasing a positive effect on WRKY53 expression. Additionally, WRKY25 and WRKY18 downregulate their own expression to prevent an excessive response. In this way, WRKY25 balances the expression and activity within the WRKY53/WRKY25/WRKY18 network to ensure a slow but progressive induction of senescence.
