Abstract

Nonsense-mediated decay (NMD) and autophagy play pivotal roles inrestricting virus infection in plants. However, the interconnection betweenthese two pathways in viral infections has not been explored. Here, it isshown that overexpression of NbSMG7 and NbUPF3 attenuates cucumbergreen mottle mosaic virus (CGMMV) infection by recognizing the viralinternal termination codon and vice versa. NbSMG7 is subjected toautophagic degradation, which is executed by its interaction with one of theautophagy-related proteins, NbATG8i. Mutation of the ATG8 interacting motif(AIM) in NbSMG7 (SMG7mAIM1) abolishes the interaction and comprises itsautophagic degradation. Silencing of NbSMG7 and NbATG8i, or NbUPF3 andNbATG8i, compared to silencing each gene individually, leads to more virusaccumulations, but overexpression of NbSMG7 and NbATG8i fails to achievemore potent virus inhibition. When CGMMV is co-inoculated withNbSMG7mAIM1 or with NbUPF3, compared to co-inoculating with NbSMG7in NbATG8i transgene plants, the inoculated plants exhibit milder viralphenotypes. These ndings reveal that NMD-mediated virus inhibition isimpaired by the autophagic degradation of SMG7 in a negative feedback loop,and a novel regulatory interplay between NMD and autophagy is uncovered,providing insights that are valuable in optimizing strategies to harness NMDand autophagy for combating viral infections.

Advanced Science

IF="15.1

https://onlinelibrary.wiley.com/doi/10.1002/advs.202400978