HISTOLOGICAL ANALYSIS OF THE EXPRESSION OF AGROBACTERIUM-RHIZOGENES ROLB-GUS GENE FUSIONS IN TRANSGENIC TOBACCO

The gene rolB from the T-DNA of Agrobacterium rhizogenes is capable of directing differentiation of roots in transformed plant cells. A detailed histological analysis of the expression of this gene in transgenic tobacco plants is presented here. Gene fusions between the promoter of rolB and the GUS reporter gene (encoding E. coli beta-glucuronidase) were utilized: tissue and cell specific GUS activity as driven by a long (1185 base pairs) and a short (306 bp) version of the rolB promoter was visualized histochemically during different phases of plant development, from embryo to flowering. The extended (1185 bp) rolB promoter is under developmental control and is specifically active in the initial cells of all types of meristems and in the vascular system (phloem, phloem parenchyma, xylem parenchyma, pericycle and pericycle-like cells) of mature organs as well as in the central cylinder of the embryo. In contrast, the 306 bp deletion of the promoter is unable to drive expression in meristematic initials but is still active in the vascular system of the seedling

Agrobacterium mediated transformation of almond: In vitro rooting through localized infection of A-rhizogenes WT

Satisfactory in vitro rooting (96.8%) was obtained in the almond cultivar Supernova through the infection of Agrobacterium rhizogenes w.t., strain 1855 NCPPB, at the base of the microcuttings. The rooting medium was that of Bourgin and Nitsch(1967) hormone-free; the addition of indolacetic acid inhibited rooting when the explants were infected (35.5%). No roots were formed by the controls not infected and not treated with indolacetic acid (0%). Southern blot analysis, made with two probes, confirmed the transgenic nature of the genomic DNA extracted from roots of the infected cuttings and excluded the contamination of bacterial DNA during the extraction. The plants were successfully transferred to soil, where the roots resumed a vigorous growth

Histological analysis of the expression of Agrobacterium rhizogenes rolB-GUS gene fusions in transgenic tobacco

The gene rolB from the T-DNA of Agrobacterium rhizogenes is capable of directing differentiation of roots in transformed plant cells. A detailed histological analysis of the expression of this gene in transgenic tobacco plants is presented here. Gene fusions between the promoter of rolB and the GUS reporter gene (encoding E. coli beta-glucuronidase) were utilized: tissue and cell specific GUS activity as driven by a long (1185 base pairs) and a short (306 bp) version of the rolB promoter was visualized histochemically during different phases of plant development, from embryo to flowering. The extended (1185 bp) rolB promoter is under developmental control and is specifically active in the initial cells of all types of meristems and in the vascular system (phloem, phloem parenchyma, xylem parenchyma, pericycle and pericycle-like cells) of mature organs as well as in the central cylinder of the embryo. In contrast, the 306 bp deletion of the promoter is unable to drive expression in meristematic initials but is still active in the vascular system of the seedling