Flachowsky Henryk, Tränkner Conny, Szankowski Iris, Waidmann Sascha, Hanke Magda-Viola, Treutter Dieter, Fischer Thilo C
Julius Kühn-Institute-Federal Research Centre for Cultivated Plants, Institute for Breeding Research on Horticultural and Fruit Crops, Dresden 01326, Germany.
Plant Breeding Institute, Christian-Albrechts-University of Kiel, Kiel 24098, Germany.
Int J Mol Sci. 2012;13(8):9992-10009. doi: 10.3390/ijms13089992. Epub 2012 Aug 10.
RNA silencing describes the sequence specific degradation of RNA targets. Silencing is a non-cell autonomous event that is graft transmissible in different plant species. The present study is the first report on systemic acquired dsRNA-mediated gene silencing of transgenic and endogenous gene sequences in a woody plant like apple. Transgenic apple plants overexpressing a hairpin gene construct of the gusA reporter gene were produced. These plants were used as rootstocks and grafted with scions of the gusA overexpressing transgenic apple clone T355. After grafting, we observed a reduction of the gusA gene expression in T355 scions in vitro, but not in T355 scions grown in the greenhouse. Similar results were obtained after silencing of the endogenous Mdans gene in apple that is responsible for anthocyanin biosynthesis. Subsequently, we performed grafting experiments with Mdans silenced rootstocks and red leaf scions of TNR31-35 in order to evaluate graft transmitted silencing of the endogenous Mdans. The results obtained suggested a graft transmission of silencing signals in in vitro shoots. In contrast, no graft transmission of dsRNA-mediated gene silencing signals was detectable in greenhouse-grown plants and in plants grown in an insect protection tent.
RNA沉默描述了RNA靶标的序列特异性降解。沉默是一种非细胞自主性事件，在不同植物物种中可通过嫁接传播。本研究是关于在苹果这种木本植物中，系统性获得性双链RNA介导的转基因和内源基因序列基因沉默的首次报道。构建了过表达gusA报告基因发夹基因结构的转基因苹果植株。这些植株用作砧木，并与过表达gusA的转基因苹果克隆T355的接穗进行嫁接。嫁接后，我们观察到T355接穗在体外的gusA基因表达降低，但在温室中生长的T355接穗中未观察到这种情况。在沉默负责花青素生物合成的苹果内源Mdans基因后也获得了类似结果。随后，我们用Mdans沉默的砧木和TNR31 - 35的红叶接穗进行嫁接实验，以评估内源Mdans的嫁接传播沉默。所获得的结果表明在体外嫩枝中存在沉默信号的嫁接传播。相比之下，在温室种植的植株和在防虫帐篷中种植的植株中未检测到双链RNA介导的基因沉默信号的嫁接传播。
