RT Journal Article SR Electronic(1) A1 Love, Andrew J. A1 Laird, Janet A1 Holt, Justin A1 Hamilton, Andrew J. A1 Sadanandom, Ari A1 Milner, Joel J.YR 2007 T1 Cauliflower mosaic virus protein P6 is a suppressor of RNA silencing JF Journal of General Virology, VO 88 IS 12 SP 3439 OP 3444 DO https://doi.org/10.1099/vir.0.83090-0 PB Microbiology Society, SN 1465-2099, AB We infected a transgenic Arabidopsis line (GxA), containing an amplicon-silenced 35S : : GFP transgene, with cauliflower mosaic virus (CaMV), a plant pararetrovirus with a DNA genome. Systemically infected leaves showed strong GFP fluorescence and amplicon transcripts were detectable in Northern blots, indicating that silencing of GFP had been suppressed during CaMV-infection. Transgenic Arabidopsis lines expressing CaMV protein P6, the major genetic determinant of symptom severity, were crossed with GxA. Progeny showed strong GFP fluorescence throughout and amplicon transcripts were detectable in Northern blots, indicating that P6 was suppressing local and systemic silencing. However, levels of 21 nt siRNAs derived from the GFP transgene were not reduced. In CaMV-infected plants, the P6 transgene did not reduce levels of CaMV leader-derived 21 and 24 nt siRNAs relative to levels of CaMV 35S RNA. These results demonstrate that CaMV can efficiently suppress silencing of a GFP transgene, and that P6 acts as a silencing suppressor., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.83090-0