AGO1 and infection: To investigate the host RNA response of V. dahliae and B. cinerea to TMV-GFP infection, we used RT-qPCR to quantify the relative abundance of two major RNAi hallmark transcripts: DCL1 and AGO1, which are involved in the recruitment of 21-nt virus-derived small interfering RNAs (vsiRNAs), assembly of the RNA-induced silencing complex (RISC), and dissemination of the silencing signal.