Sun Chuanxin, Höglund Anna-Stina, Olsson Helena, Mangelsen Elke, Jansson Christer
Department of Plant Biology & Forest Genetics, The Swedish University of Agricultural Sciences, PO Box 7080, SE-75007 Uppsala, Sweden.
Plant J. 2005 Oct;44(1):128-38. doi: 10.1111/j.1365-313X.2005.02515.x.
Sugar signalling cascades are important components of regulatory networks in cells. Compared with the situation in bacteria, yeast and animals, participants of the sugar signalling pathways in plants are poorly understood. Several genes involved in starch synthesis are known to be sugar inducible, although the signal transduction pathways remain undisclosed. We reported recently the isolation of SUSIBA2, a transcription factor involved in sugar-mediated regulation of starch synthesis. Here, we used antisense oligodeoxynucleotide (ODN) inhibition, a powerful approach in medical sciences, to block the effects of SUSIBA2 in sugar-treated barley leaves. The uptake and intracellular trafficking of an 18-mer susiba2 antisense ODN in leaves were followed by confocal microscopy. Administration of the antisense ODN to the leaves impeded susiba2 expression by RNase H activation. This dramatically diminished the ectopic expression of the iso1 and sbeIIb genes and resulted in altered starch synthesis. This study illustrates the successful exploitation of the antisense ODN technology in plant biology, e.g. as a rapid antecedent to time-consuming transgenic studies, and identifies SUSIBA2 as a transcriptional activator in plant sugar signalling. Based on our findings, we propose a model for sugar-signalling control of starch synthesis.
糖信号级联是细胞调控网络的重要组成部分。与细菌、酵母和动物的情况相比，植物中糖信号通路的参与者还知之甚少。已知一些参与淀粉合成的基因是糖诱导型的，尽管信号转导途径仍不明确。我们最近报道了SUSIBA2的分离，它是一种参与糖介导的淀粉合成调控的转录因子。在这里，我们使用反义寡脱氧核苷酸（ODN）抑制法（医学领域一种强大的方法）来阻断SUSIBA2在经糖处理的大麦叶片中的作用。通过共聚焦显微镜追踪18聚体susiba2反义ODN在叶片中的摄取和细胞内运输。将反义ODN施用于叶片通过激活RNase H阻碍了susiba2的表达。这显著减少了iso1和sbeIIb基因的异位表达，并导致淀粉合成改变。这项研究说明了反义ODN技术在植物生物学中的成功应用，例如作为耗时的转基因研究的快速前期研究，并确定SUSIBA2是植物糖信号中的转录激活因子。基于我们的发现，我们提出了一个淀粉合成的糖信号控制模型。
