Newly synthesized vRNAs released from the replication complexes fight against the host’s defense pathways. Therefore, for a robust and productive infection, the viral RNA molecules need to be able to suppress gene silencing and cope also with the other cellular RNA metabolic pathways and degradation machineries (reviewed in [1]).
Multifunctional potyviral protein called helper component-proteinase (HCPro) is a suppressor of RNA silencing. We found that it induces RNA granules (PGs), which are required to overcome active RNA silencing, achieve optimal viral gene expression and support virus accumulation [2]. We proposed that PGs are the sites for active RNA silencing suppression. Many of the PG-associated host factors are important susceptibility factors of PVA infection.