Three gene products of a begomovirus–betasatellite complex restore expression of a transcriptionally silenced green fluorescent protein transgene in Nicotiana benthamiana

摘要: Single-stranded DNA geminiviruses replicate via double-stranded intermediates forming mini-chromosomes that are targets for transcriptional gene silencing (TGS) in plants. The ability of the cotton leaf curl Kokhran virus (CLCuKoV)–cotton Multan betasatellite (CLCuMuB) proteins, replication-associated protein (Rep), activator (TrAP), C4, V2 and βC1, to suppress TGS was investigated by using Nicotiana benthamiana line 16-TGS (16-TGS) harbouring a transcriptionally silenced green fluorescent (GFP) transgene. Inoculation plants with recombinant potato X vector carrying Rep, TrAP or βC1 resulted re-expression GFP. Northern blot analysis confirmed observed GFP fluorescence associated mRNA accumulation. These results indicated proteins CLCuKoV–CLCuMuB can re-activate expression transgene N. benthamiana. Although TrAP, have, other begomoviruses begomoviruses–betasatellites, been previously shown have suppressor activity, this is first report demonstrating single begomovirus–betasatellite complex encodes three suppressors TGS.