Figure 4.

CKs induce resistance independent of SA, JA, ROS, and extracellular invertase activity. A, Effect of a 24-h kinetin application (10 μm) before PstT infection on symptom development in nahG-overexpressing tobacco leaves in comparison with the control at 8 dpi. Leaves were infiltrated at two sites with PstT (left) and 10 mm MgCl₂ (right). B, Effect of transient 4xJERE:ipt expression and PstT infection on H₂O₂ formation. Tobacco leaves were preinfiltrated with A. tumefaciens with (ipt) or without (0) the 4xJERE:ipt construct followed by a second infiltration with PstT (Pst). Leaves were stained with DAB to visualize H₂O₂ formation at 24 h after preinfiltration of A. tumefaciens (0 hpi; left), 24 h after infiltration of PstT (24 hpi; middle), and at the time of symptom development 168 h after PstT infiltration (168 hpi; right). C, Effect of CIN1 expression in TET:CIN1 tobacco leaves induced by a 24-h feeding of 1 mg L⁻¹ TET in comparison with a 24-h application of 10 μm kinetin prior to infection and water control treatment on symptom development at 10 dpi. Leaves were infiltrated with PstT at two sites per leaf half.