Figure 9.

GUS Activity of the Upstream Region of St BEL5.

The promoter sequence used in this construct to drive GUS expression contained a 202-nucleotide intron located within 103 nucleotides of the 5′ UTR and 1971 nucleotides of genomic sequence upstream from the 5′ UTR (A). GUS activity was detected in stolons and newly formed tubers ([B], arrow) and in leaf veins and petioles ([C] to [E]). The plant in (D) was cultured in vitro under LD conditions. All other material was from soil-grown plants. The leaf in (F) is 30 d older than the leaf in (E). Transverse section of a petiole exhibiting staining throughout the tissue, with the greatest level of activity around vascular cells is shown in (G) (arrows). Under higher magnification, blue staining was detected in companion cells (cc), in parenchyma-associated phloem cells (pp) ([H] and [I]), and in xylem cell walls (x) (H). No staining was observed in transverse sections of internodal regions of the stem (J). Bars = 100 μm in (G) and (J), 20 μm in (H), and 5.0 μm in (I).