Identification and confirmation of MhAGO1 as a target of miR168. (A) Identification of the predicted miR168 target site as determined with 5′ RLM-RACE. The position of 5′ RLM-RACE products is indicated with an arrow. The numbers above the sequence indicate the detected cleavage site in independent clones. (B) Nucleotide sequences of two versions of AGO1 with different sensitivity to miR168: MhAGO1 (sensitive) and mMhAGO1 (insensitive). (C) Schematic diagrams of constructs used in co-transformation. (D and E) Histochemical assay (D) and GUS activity (E) of tobacco leaves infiltrated with different constructs. The different constructs were agroinfiltrated into fully expanded leaves of 6-week-old tobacco plants. GUS staining was performed 3 d after the injection. The presented images of leaves in (D) are representative of the results obtained from three independent experiments. Data presented in (E) represent the mean ± SD of three independent experiments (n = 3). Different letters denote significant differences between the constructs (P ≤ 0.05).