Nevertheless, increase in TAS3-derived ta-siRNAs without reduction of TAS3 transcript in V592-infected Col-0, suggests increase in TAS3 transciption in response to V592 infection in keeping production of TAS3-derived ta-siRNAs, that in turn to target ARF2, ARF3 and ARF4 involving in auxin signal pathway (Fahlgren et al. 2006). The gene discussed is ARF4; the disease is infection.