Gittins J R, Pellny T K, Hiles E R, Rosa C, Biricolti S, James D J
Plant Breeding and Biotechnology, Horticulture Research International, East Malling, West Malling, Kent, ME19 6BJ, UK.
Planta. 2000 Jan;210(2):232-40. doi: 10.1007/PL00008130.
It is desirable that the expression of transgenes in genetically modified crops is restricted to the tissues requiring the encoded activity. To this end, we have studied the ability of the heterologous ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) small-subunit (SSU) gene promoters, RBCS3CP (0.8 kbp) from tomato (hycopersion esculentum Mill.) and SRS1P (1.5 kbp) from soybean (Glycine max [h.] Mers.), to drive expression of the beta-glucuronidase (gusA) marker gene in apple (Malus pumila Mill.). Transgenic lines of cultivar Greensleeves were produced by Agrobacterium-mediated transformation and the level of gusA expression in the vegetative tissues of young plants was compared with that produced using the cauliflower mosaic virus (CaMV) 35S promoter. These quantitative GUS data were assessed for their relationship to the copy number of transgene loci. The precise location of GUS activity in leaves was identified histochemically. The heterologous SSU promoters were active primarily in the green vegetative tissues of apple, although activity in the roots was noticeably higher with the RBCS3C promoter than with the SRS1 promoter. The mean GUS activity in leaf tissue of the SSU promoter transgenics was approximately half that of plants containing the CaMV 35S promoter. Histochemical analysis demonstrated that GUS activity was localised to the mesophyll and palisade cells of the leaf. The influence of light on expression was also determined. The activity of the SRS1 promoter was strictly dependent on light, whereas that of the RBCS3C promoter appeared not to be. Both SSU promoters would be suitable for the expression of transgenes in green photosynthetic tissues of apple.
理想的情况是，转基因作物中转基因的表达仅限于需要编码活性的组织。为此，我们研究了来自番茄（Lycopersicon esculentum Mill.）的异源核酮糖-1,5-二磷酸羧化酶/加氧酶（Rubisco）小亚基（SSU）基因启动子RBCS3CP（0.8 kbp）和来自大豆（Glycine max [L.] Merr.）的SRS1P（1.5 kbp）驱动苹果（Malus pumila Mill.）中β-葡萄糖醛酸酶（gusA）标记基因表达的能力。通过农杆菌介导的转化产生了品种Greensleeves的转基因株系，并将幼龄植物营养组织中gusA的表达水平与使用花椰菜花叶病毒（CaMV）35S启动子产生的表达水平进行了比较。评估了这些定量GUS数据与转基因位点拷贝数的关系。通过组织化学方法确定了叶片中GUS活性的确切位置。异源SSU启动子主要在苹果的绿色营养组织中具有活性，尽管使用RBCS3C启动子时根部的活性明显高于使用SRS1启动子时的活性。SSU启动子转基因植物叶片组织中的平均GUS活性约为含有CaMV 35S启动子的植物的一半。组织化学分析表明，GUS活性定位于叶片的叶肉和栅栏细胞中。还确定了光照对表达的影响。SRS1启动子的活性严格依赖于光照，而RBCS3C启动子的活性似乎并非如此。两个SSU启动子都适合在苹果的绿色光合组织中表达转基因。
