Fig. 5. Histochemical dyeing assay of GUS in transformed tobacco leaves for analyzing BrMYB2 promoter activity.

aGUS constructs containing different lengths of BrMYB2 promoter sequences (based on 11S91). Schematic diagram of constructs utilized for transient transformation of tobacco ‘NC89’ leaves that were 6 cm in size (~28 DAS [days after sowing]). Tobacco leaves were infiltrated with different plasmids from bacteria at a concentration of OD₆₀₀ = 0.530 and cultured for 72 h under a 12-h light/12-h dark photoperiod at 23 °C (125 mmol m^–2 s^–1). The leaves were imaged after GUS solution staining and alcohol decolonization. b, f, j Constructs with a 2270 bp long BrMYB2 promoter (based on that of 11S91). c, g, k Constructs with a 2008 bp long BrMYB2 promoter (based on that of 11S91). d, h, l Constructs with a 791 bp long BrMYB2 promoter (based on that of 11S91). n Construct with 642 bp long BrMYB2 promoter. o Construct with a 498 bp long BrMYB2 promoter. e Negative control: noninfiltrated leaves. i Positive control: leaves infiltrated with the CaMV35S:GUS construct. m Negative control: leaves infiltrated with the GUS construct without CaMV35S promoter. The data as shown are representative of three independent repeats (n = 3). The scale bar is 2.5 cm