Fig. 4

 A Transcription activity assay of SsCUC2. The ORF of SsCUC2 was introduced into the yeast expression vector pGBKT7. Yeast cells cotransformed with pGBKT7-53 + pGADT7-T were used as the positive control, and yeast cells with empty vector pGBKT7 were used as a negative control. The yeast cultures harboring respective vectors were grown on the synthetic medium supplied with dextrose (SD) in the absence of Trp (SD/ -T, left panel), on SD medium in the absence of Leu, Trp, and His (SD/ -L -T -H, middle panel) and on SD medium with α-galactosidase and in the absence of Leu, Trp, and His (SD/ -L -T –H + X-α-gal, right panel). Yeast cells were incubated until OD₆₀₀ reached 1 and then diluted 10- and 100-fold for assays. B Subcellular localization of SsCUC2 in tobacco epidermal cells (lower panel)