中文摘要：

RNA 干扰(RNAi ) ，为 post-transcriptionalgene silencing 的最新发现的方法之一，广泛地被用来为介绍一个 RNA silencing 信号进植物通过转基因的方法调查基因函数。在现在的学习，我们构造了， adexamethazone (DEX ) 怀有特定的顺序碎片(168-bp ) 的可诱导的 RNAi 二进制向量对 KatB 和 KatC 相应， Arabidopsis 的二 kinesin isoform 基因，它被证明在导致DEX 的转基因的工厂导致 KatB 和 KatC 的 post-transcriptional 基因 silencing 。转基因的同型结合的 Arabidopsis 上的 RT-PCRand 北污点分析(作为 RNAi 类型工厂称为) 证明那 DEX 动机引起 KatB 和 KatC mRNA 降级。与一个简化方法， Arabidopsisgrafting 有效地在 RNAi 类型和野类型的线之间被执行。目标基因 mRNAlevels 基于半量的 RT-PCR 被测试。我们的结果证明 DEX-inducedgene silencing 信号能在野类型的根茎或接穗在 KatB 和 KatC mRNA 导致减小，显示 RNAi 的 silencing 信号能越过接枝连接双向地被播送 RNAi 种是否是接穗或股票。与 grafted 烟草上的以前报导的结果相对照， post-transcriptional 基因 silencing 信号的传播在 grafted Arabidopsis 由 RNAi 引起了在烟草是比那更有效的。

英文摘要：

RNA interference （RNAi）, one of the newly found ways for post-transcriptional gene silencing, has been widely used to investigate gene functions through transgenic methods for introducing an RNA silencing signal into plants. In the present study, we constructed a dexamethazone （DEX）-inducible RNAi binary vector harboring a specific sequence fragment （168-bp） homologous to KatB and KatC, two kinesin isoform genes of Arabidopsis, which were proved to result in the post-transcriptional gene silencing of KatB and KatC in DEX-induced transgenic plants. RT-PCR and Northern blot analysis on transgenic homozygous Arabidopsis （termed as RNAi-type plants） showed that DEX inducement causes KatB and KatC mRNA degradation. With a simplified method, Arabidopsis grafting was effectively performed between RNAi-type and wild-type lines. The target gene mRNA levels were tested based on semi-quantitative RT-PCR. Our results demonstrateed that DEX-induced gene silencing signals could result in a reduction in KatB and KatC mRNA in the wild-type rootstocks or scions, indicating that silencing signals of RNAi could be transmitted bidirectionally across the graft junction whether RNAi-plants were scions or stocks. In contrast to the previously reported results on grafted tobacco, the transmission of post-transcriptional gene silencing signals caused by RNAi in grafted Arabidopsis is more effective than that in tobacco.