sentence: These results were surprising in light of multiple previous reports that have demonstrated that RDR1 is involved in defence against viruses : TMV and tobacco rattle virus in Arabidopsis2328 ; TMV , PVX and PVY in tobacco2236 , and against TMV , as well as two other tobamoviruses ( turnip vein-clearing virus and sunn-hemp mosaic virus ) in N. benthamiana2550 .