AGO4 and infection: Conversely, argonaute protein 2 (AGO2) that together with AGO4 are the effectors in the RNAi pathway against the infection of RNA viruses showed a moderate up-regulation only in Ma (FC = 1.54; RQ = 0.94) and in all graft combinations (FC between 1.39 and 1.68; RQ between 1.4 and 2.05).