New plant growth-modifying properties of the Agrobacterium T-6b oncogene revealed by the use of a dexamethasone-inducible promoter.

摘要: Agrobacterium 6b oncogenes induce tumours on Nicotiana glauca and enations associated modifications in transgenic N. tabacum plants. 2x35S-AB-6b tobacco rootstocks produced a graft-transmissible factor that induced wild-type scions; the nature of this enation remains to be identified. Here, we report properties plants carrying dexamethasone-inducible T-6b gene (dex-T-6b). Induction with dex led complex growth modifications, many which have not been reported previously. Modifications were only found growing tissues; mature tissues remained unaffected. Growth could either stimulated or inhibited. Dex induction young morphogenetic gradients included enations, tubular leaves fragmented leaf primordia. Root elongation was increased slowed down, while radial root strongly enhanced. Additional cell divisions pericycle vasculature. Enation import from did same effects as local synthesis: normal scions grafted dex-T-6b formed whereas at shoot apex numerous dark-green spots abaxial side leaves. In patch assays, 23-kDa protein move through enter vascular system. This fact spontaneous mutants modify contrary indicate might factor.