Detection of Sm-miR408 overexpressing (OE) transgenic lines. (A) PCR amplification product of 35S promoter from transgenic Nicotiana benthamiana genomic DNA (gDNA). Lanes: M, DL2000 DNA marker; WT, wild-type plants as negative control; 1-6, different transgenic lines; P, plasmids as positive control. (B,C) Relative expression levels of Sm-MIR408 (B) and mature miR408 (C) in transgenic lines and WT. (D) Relative expression levels of copper-transporting ATPase PAA2 and uclacyanin-2 in transgenic lines and WT. The data represent means ± SD of three independent experiments. Significant differences were determined using Duncan’s multiple range test (indicated by different letters at p < 0.05).