Effects of MhAGO1 silencing on B. dothidea resistance, ROS production, cell death and SA-mediated basal defense responses. (A) Northern blot analysis of MhAGO1 for high molecular weight (HMW) and low molecular weight (LMW) RNAs, and miR168 in MhAGO1 silenced leaves. U6 and EF-1α served as internal controls. Ten random leaves were pooled in each experiment and used as a biological replicate. (B) Percentage of infected leaves at 24 and 96 hpi in different disease level categories. (C) Representative symptoms in MhAGO1 silenced M. hupehensis leaves infected with B. dothidea. (D) Quantification of B. dothidea growth on infected leaves infiltrated with the MhAGO1 RNAi construct. (E) Changes in the level of H₂O₂ generation in MhAGO1 silenced leaves at different time points (hpi) after B. dothidea inoculation. (F) Level of cell death in MhAGO1 silenced leaves after B. dothidea inoculation. (G) Constitutive expression of PR genes and PAL in MhAGO1 silenced leaves. (H and I) Accumulation of PR1 at different time points after SA treatment (H) or B. dothidea inoculation (I) in MhAGO1 silenced leaves. For (G), (H) and (I), EF-1α was used as the internal control. Asterisks in (G) indicate significant differences in expression relative to the expression in non-infiltrated leaves. Significant differences between the constitutive expression levels of the PR1 gene and that at different time points in the different treatments are indicated by an asterisk in (H) and (I) (*P ≤ 0.05; **P ≤ 0.01). All data represent the mean ± SD of three biological replicates (n = 3). WT, non-infiltrated control; Vector, empty vector control.