GhFT interacts with GhFDs to activate GhAP1.1 and GhARF19 expression when co-expressed in Arabidopsis protoplasts. (A) Schematic diagrams of the effector, reporter and internal control constructs used in the dual-LUC reporter assays. The effector constructs contained the coding regions of the cDNAs for GhFDs and GhFT placed independently between the Cauliflower mosaic virus (CaMV) 35S promoter and a nopaline synthase (Nos) terminator. The reporter constructs consisted of ∼2.0-kb upstream sequences of the start codons of GhAP1.1 and GhARF19, a luciferase gene, and the Nos terminator. Renilla luciferase driven by CaMV 35S was used as an internal control. (B, C) Relative luciferase activities after cotransfection of Arabidopsis protoplasts with the effector and reporter plasmids. The empty BD effector was used as a negative control. Values are means ± standard deviations (n = 3).