Figure 1.

Quantitative bioassay for octopine, and distribution patterns throughout transgenic tobacco. A, Representative standard curve for detecting octopine in the growth medium of Agrobacterium tumefaciens strain KYC16 in the absence of wild-type plant extract (♦), with the addition of extract from 10 mg fresh weight wild-type leaf tissue (▴), and with the addition of extract from 50 mg fresh weight wild-type leaf tissue (●). B, Leaf section of NtGOG-12 tobacco plant stained with the β-glucuronidase (GUS) substrate 5-bromo-4-chloro-3-indolyl-β-d-GlcUA (X-GlcA) and cleared of chlorophyll. Staining in a minor vein is indicated with an arrow, whereas an arrowhead indicates the absence of staining in a larger vein. C, Representative distribution of octopine in grafted tobacco plants. Stock, Mature leaf tissue from the indicated transgenic tobacco plant; solid bars, NtGOG-12; and hollow bars, NtGOG-20. Apoplast, Apoplast washing fluid collected from a mature leaf sample of the indicated transgenic plant, corrected for dilution, and assuming a specific gravity of one. Scion, Apical bud tissue of a wild-type scion grafted to the indicated transgenic stock plant.