Abstract: 【Objective】To determine and compare the induction efficiency of RNA silencing triggered by different construction transgene of 3′ -terminal segment derived from the Potato virus Y (veinal necrosis strain, PVYN ) coat protein gene.【Method】Transgenic tobacco plants expressing untranslated direct repeats (DR) and inverted repeats (IR) of 3′ -terminal 202bp of the PVYN coat protein gene were obtained via Agrobacterium tumefaciens-mediated transformation system. 【Result】Resistance assay of the transgenic plants indicated that none of the DR-transgenic plants are resistant to PVY, but 82.8% of IR-transgenic plants showed high resistance. Northern blot analysis revealed an inverse correlation between transgene transcript accumulation and virus resistance.【Conclusion】These results showed that the resistance was RNA-mediated. The proportion of the resistant transgenic plants induced by 3′ -terminal segment transgene of PVYN is higher than that induced by 5′ -terminal segment.

Key words: Potato virus Y, RNA-mediated virus resistance, Ds RNA, RNA silencing