Gene silencing in plants. p 35S GFP LB RB PFG intron Transcription CAP Poly A DICER RISC p 35S GFP LB RB Translation CAP Poly A Transcription Fluorescence gene silencing mRNA degradation No Fluorescence RISC

1.a. Gene silencing of transiently expressed sequences. UV Nb p 35S GFP LB RB p 35S GFP LB RB p 35S GFP LB RB PFG intron

1.b. Triggering gene silencing of established transgene by transient expression. GFP UV p 35S LB RB PFG intron

1.c. Virus-induced gene silencing (VIGS) pTRV2 CP p 35S LB RB RZ PDS Nt Agroinfiltration PTGS PDS Sistemic PTGS pTRV1 MP 16K RpRd

2. Systemic gene silencing. UV GFP GFP GFP Agroinfiltration PTGS GFP Sistemic PTGS p 35S GFP LB RB PFG intron

3.a. Suppressing gene silencing of transiently expressed sequences. UV Nb p 35S GFP LB RB HcPro PFG intron

3.b. Silencing of trangenes or endogenous genes cannot be established in the presence of silencing suppressor. p 35S HcPro LB RB GFP UV PFG intron

3.c. Suppression of gene silencing mediated by virus infection. Plant silenced for the Magnesium chelatase gene. PVY infection.