The viral F-box protein P0 induces an ER-derived autophagy degradation pathway for the clearance of membrane-bound AGO1

Abstract

Significance The viral suppressor of RNA silencing P0 is known to target plant antiviral ARGONAUTE (AGO) proteins for degradation via an autophagy-related process. Here we utilized P0 to gain insight into the cellular degradation dynamics of AGO1, the major plant effector of RNA silencing. We revealed that P0 targets endoplasmic reticulum (ER)-associated AGO1 by inducing the formation of ER-related bodies that are delivered to the vacuole with both P0 and AGO1 as cargos. This process involves ATG8-interacting proteins 1 and 2 (ATI1 and ATI2) that interact with AGO1 and negatively regulate its transgene-silencing activity. Together, our results reveal a layer of ER-bound AGO1 posttranslational regulation that is manipulated by P0 to subvert plant antiviral defense.