Post-transcriptional gene silencing signal could move rapidly and bidirectionally in grafted Arabidopsis thaliana

Abstract

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.

Virus‐induced gene silencing can persist for more than 2 years and also be transmitted to progeny seedlings in Nicotiana benthamiana and tomato

“…The other likely possibility could be that the initial inoculum of TRV is the actual source of virus that continue to escape silencing, multiply and spread to newer tissues. Apart from the presence of TRV, it is also possible that siRNA or other silencing signals (Li et al. , 2006; Palauqui et al.…”

“…The other likely possibility could be that the initial inoculum of TRV is the actual source of virus that continue to escape silencing, multiply and spread to newer tissues. Apart from the presence of TRV, it is also possible that siRNA or other silencing signals (Li et al, 2006;Palauqui et al, 1997) can account for persistence of gene silencing even without the presence of virus. However, short-distance movement of the silencing signal of PDS gene during potato virus-X (movement defective mutant)based VIGS in N. benthamiana has produced only a weak and transient photo-bleaching phenotype (Voinnet, 2001).…”

Graft Transmission of RNA Silencing to Non-Transgenic Scions for Conferring Virus Resistance in Tobacco

“…Recently, siRNA was shown to be able to pass through the graft junction and that siRNA triggers RNA silencing in recipient cells [19], [20]. Most experiments on the graft transmissions of RNA silencing have been shown with transgenic plants [1], [21]–[25]. The transmission of post-transcriptional gene silencing (PTGS) to transgenic scions occurred from transgenic tobacco plants silenced with both the transgene and endogenous gene of the nitrate reductase gene (Nia) but that PTGS was never transmitted to non-transgenic scions [1].…”