CAT and infection: In contrast, the expression of the wheat catalase gene (TaCAT), which is involved in ROS removal, was significantly increased (∗P < 0.05, ∗∗P < 0.01) in the TaRar1-knockdown leaves after infection with CYR23 (Figure 8C), implying that the reduction of H2O2 accumulation was the result of higher expression of TaCAT. Real-time PCR revealed little change in TaRar1 transcript level when treated wheat plants with exogenous H2O2 (100 mM) (Figure 8D).