Fig. 10.

Proposed model for the possible roles of autophagy in the potyviral infection. Infection by positive-sense RNA viruses activates autophagy in plant cells. Beclin1 (ATG6) binds to the GDD motif of the viral RNA-dependent RNA polymerase (RdRp) to inhibit virus replication, which is independent of the autophagy pathway. Beclin1 may also serve as a cargo receptor to interact with the viral RdRp and target the RdRP-containing virus replication complex via the interaction of Beclin1 with other autophagy proteins (e.g., ATG8a) to autophagosomes for degradation. The mechanic details leading to the autophagy-mediated degradation remain to be fully understood. Simultaneously, HC-Pro, a virulence factor and the major potyviral VSR, is hijacked by host rgs-CaM to induce its degradation by the autophagy pathway⁵⁶. Meanwhile, the second potyviral VSR, VPg, mediates the degradation of RNA silencing components SGS3 and RDR6 via the autophagy pathway to suppress antiviral RNA silencing⁵⁸