Spatial and temporal patterns of transcription of a wound‐induced gene in potato.
Spatial and temporal patterns of transcription of a wound‐induced gene in potato.
复制标题
马铃薯伤口诱导基因转录的空间和时间模式。
作者：
A. Stanford;D. H. Northcote;Michael Bevan
利用编码马铃薯win2基因与编码β -葡萄糖醛酸酶（GUS）的报告基因的转录融合，研究了转基因马铃薯和烟草植株创伤诱导基因活性的时空格局。含有全长win2启动子的基因融合体在转基因马铃薯中对机械损伤的响应得到了正确的调节，而在异源寄主烟草中则没有。win2转录起始位点上游大于560bp的序列对伤口诱导很重要。通过对几个独立的win2‐‐GUS转化体的损伤叶和老化叶提取物进行荧光分析，发现GUS活性的显著诱导与win2 mRNA积累的动力学一致。对受伤叶片的组织化学分析表明，转录首先发生在紧挨着伤口的细胞中，然后在离伤口较远的血管系统相关细胞中逐渐被诱导。在块茎中，对伤害的局部反应被观察到，并且只有当块茎开始发芽时，这种反应才会扩散到块茎的其他部分。由此可见，活跃的血管运输是创面反应扩散的必要条件。Win2‐‐GUS融合也作为正常植物发育的一部分表达，因为GUS活性在发育中的芽和与未受伤块茎皮孔相关的细胞层中被检测到。
Transcriptional fusions between the gene encoding win2 from potato and the reporter gene encoding beta‐glucuronidase (GUS) have been used to study the spatial and temporal patterns of wound induced gene activity in transgenic potato and tobacco plants. Gene fusions containing a full length win2 promoter were found to be correctly regulated in response to mechanical wounding in transgenic potato, but not in the heterologous host, tobacco. Sequences greater than 560 bp upstream of the transcription start site of win2 were shown to be important for wound inducibility. The dramatic induction of GUS activity detected using fluorometric assays of extracts of wounded and aged leaves of several independent win2‐‐GUS transformants was consistent with the kinetics of win2 mRNA accumulation. Histochemical analysis of wounded leaves showed that transcription first occurred in cells immediately adjacent to the wound, and was then progressively induced in cells associated with the vascular system at a distance from the wound site. In tubers, a localized response to wounding was observed, and this only spread to other parts of the tuber if it had started to sprout. It was concluded that active vascular transport was necessary for the spread of wound response. Win2‐‐GUS fusions were also expressed as part of normal plant development, as GUS activity was detected in the developing buds and in a layer of cells associated with the lenticels of unwounded tubers.