Enhanced resistance of GhWRKY15 -overexpressing tobacco to viruses. (A) Northern blot analysis of the expression levels of GhWRKY15 in T1 transgenic and WT tobacco under normal conditions. Two leaves were tested for the GhWRKY15 transgenic tobacco. WT: wild-type. (B) Leaf symptoms of tobacco plants infected with TMV (10 days post-inoculation) or CMV (14 days post-inoculation). OE: GhWRKY15-overexpressing tobacco; Mock: mock inoculation; CP: coat proteins. (C) RT-PCR analysis of the expression levels of the CP gene in infected transgenic lines (OE1, OE2 and OE3) and the WT line. (D) TMV and CMV titres in the transgenic lines and the wild-type lines. The data are presented as the mean ± standard error from three independent experiments.