Plant and Soil Sciences Laboratory, Department of Agriculture and Ecology, Faculty of Life Sciences, University of Copenhagen, Frederiksberg C, Denmark.
Plant Biotechnol J. 2010 Feb;8(2):211-22. doi: 10.1111/j.1467-7652.2009.00478.x. Epub 2009 Dec 28.
Growth retardation is an important breeding aim and an essential part of horticultural plant production. Here, the potential of transferring the Arabidopsis short internode (shi) mutant phenotype was explored by expressing the AtSHI gene in the popular ornamental plant Kalanchoë. A 35S-AtSHI construct was produced and transferred into eight genetically different cultivars of Kalanchoë by Agrobacterium tumefaciens. The resulting transgenic plants showed dwarfing phenotypes like reduced plant height and diameter, and also more compact inflorescences, as a result of increased vegetative height. The shi phenotype was stable over more than five vegetative subcultivations. Compared with Arabidopsis, the ectopic expression of AtSHI in Kalanchoë showed several differences. None of the Kalanchoë SHI-lines exhibited alterations in leaf colour or morphology, and most lines were not delayed in flowering. Moreover, continuous treatment of lines delayed in flowering with low concentrations of gibberellins completely restored the time of flowering. These features are very important as a delay in flowering would increase plant production costs significantly. The effect of expression controlled by the native Arabidopsis SHI promoter was also investigated in transgenic Kalanchoë and resulted in plants with a longer flowering period. Two AtSHI like genes were identified in Kalanchoë indicating a widespread presence of this transcription factor. These findings are important because they suggest that transformation with the AtSHI gene could be applied to several species as a tool for growth retardation, and that this approach could substitute the use of conventional chemical growth regulation in plant production.
生长迟缓是一个重要的育种目标，也是园艺植物生产的重要组成部分。在这里，通过在流行的观赏植物长寿花中表达拟南芥短节间（shi）突变体表型，探索了转移 AtSHI 基因的潜力。生成了 35S-AtSHI 构建体，并通过根癌农杆菌将其转移到 Kalanchoë 的八个不同遗传品种中。结果表明，转基因植株表现出矮小的表型，如降低了植物的高度和直径，同时也增加了营养生长高度，使花序更加紧凑。该 shi 表型在超过五次营养继代培养中保持稳定。与拟南芥相比，AtSHI 在长寿花中的异位表达表现出一些差异。Kalanchoë SHI 系中没有一个表现出叶片颜色或形态的改变，大多数系没有延迟开花。此外，对延迟开花的系进行低浓度赤霉素处理完全恢复了开花时间。这些特征非常重要，因为开花延迟会显著增加植物生产成本。还研究了由天然拟南芥 SHI 启动子控制表达的影响，结果表明在转基因长寿花中，开花期更长。在 Kalanchoë 中鉴定出了两个 AtSHI 样基因，表明这种转录因子广泛存在。这些发现很重要，因为它们表明，用 AtSHI 基因转化可以作为生长迟缓的工具应用于几个物种，并且这种方法可以替代植物生产中常规化学生长调节的使用。
