Plant viruses account for almost 50% of the pathogens responsible for emerging and re-emerging plant diseases worldwide. Unlike fungi or bacteria, which have relatively large genomes, plant RNA viruses encode few proteins, and these are unable to facilitate completion of their life cycles independent of their hosts. The success of viral infection depends on the deployment of host cell machineries, including host-encoded virus-compatible proteins called susceptibility factors (S genes) or host factors, whose modification causes loss of susceptibility, passive resistance, or recessive resistance. Bymovirus transmitted by the soil-borne plasmodiophorid Polymyxa graminis severely threaten globally important cereal crops, including wheat and barley. The bymovirus barley yellow mosaic virus (BaYMV) and barley mild mosaic virus (BaMMV) cause the yellow mosaic disease of barley, and the wheat yellow mosaic virus (WYMV) causes the yellow mosaic disease of wheat. In barley two host susceptibility factors to BaYMV/BaMMV been identified, namely protein disulphide isomerase like 5-1 (HvPDIL5-1) and the eukaryotic translation initiation factor 4E (HveIF4E), while in hexaploid wheat none of host factors to WYMV was identified. To test the hypothesis if the recessive resistance in polyploid species was blinded by functional redundancy of the homoeoalleles, we applied the CRISPR/Cas9 genome editing technology to simultaneously knockout three homoeoalleles of TaPDIL5-1 and TaeIF4E in hexaploid wheat. Single, double, and triple knockout mutants of TaPDIL5-1 or TaeIF4E were obtained through cross-pollination and marker-assisted selection. The single- and double-mutants were susceptible to WYMV inoculation, while the triple-mutants showed complete resistance, no matter for TaPDIL5-1 or TaeIF4E edited lines. No yield penalty in TaPDIL5-1 edited wheat lines was observed, whereas an increase on plant height and delayed heading date were observed or TaeIF4E knockout lines. Several species in the genera Triticum and Aegilops were found to vary in the level of WYMV accumulation, suggesting the occurrence of WYMV resistance in wheat progenitors and relatives. These results demonstrate a strategy to uncover recessive virus resistance in polyploid plants (i.e. hexaploid wheat) by editing orthologs of susceptibility factor genes identified in their diploid progenitors or relatives.