Friend or Enemy: A Dual Role of Autophagy in Plant Virus Infection

Abstract

Autophagy is a primary protective process that involves removing damaged organelles or dysfunctional proteins in eukaryotes. The autophagy pathway not only maintains cellular homeostasis, but also modulates the host's cellular response to pathogen infection. Several studies proved that autophagy plays a dominant role in plant fitness and immunity. As intracellular parasites, the replication and spread of viruses entirely rely upon the molecular machinery of the host cell, including the autophagy process. Plant viruses severely affect crop yields and quality. During infection, complex interactions occur between viral proteins and host factors in relation to plant defense and virus counter-defense. An increasing number of studies demonstrated that plants use autophagy to eliminate and inhibit viruses; some viruses were shown to manipulate the process of autophagy to promote their own replication and survival in plant cells. In this review, we summarize recent advances in plant autophagy, with an emphasis on the role of autophagy in plant virus infection.

Emerging Roles of the Selective Autophagy in Plant Immunity and Stress Tolerance

“…The roles of selective autophagy in plant–pathogen interactions have been extensively reviewed recently [ 10 , 12 , 41 , 46 , 47 ]. Here, we just briefly review the arms race between plant and pathogens and focus our attention on the newest findings.…”

“…Recently, Marshall et al [ 21 ] showed that inactive 26S proteasomes are removed via a mechanism called proteaphagy, establishing a functional link between the two major degradation pathways. Furthermore, selective autophagy also plays a critical role in the clearance of invading pathogens (xenophagy) including bacteria, viruses, and fungi [ 11 , 13 , 39 , 40 , 41 ]. Since numerous excellent reviews have covered the pexophagy [ 42 , 43 ], chloropahgy [ 28 , 44 , 45 ], ER-phagy [ 3 ], proteaphagy [ 21 ], and xenophagy [ 11 , 13 , 41 , 46 , 47 ], we just focus our attention on the newly emerged features and the novel roles of the selective autophagy in response to both biotic and abiotic stresses in plants.…”

Selective autophagic receptor NbNBR1 prevents NbRFP1-mediated UPS-dependent degradation of βC1 to promote geminivirus infection

“…Based on the microarray study, Laura et al found that many genes involved in autophagy pathway were up-regulated in tomato after infection by tomato yellow leaf curl Sardinia virus [8]. Many reports have demonstrated that autophagy can be activated upon virus infection to play important roles in plant resistance to virus infection [9][10][11][12][13][14]. For example, autophagy can regulate plant hypersensitive cell death (PCD) response to restrict tobacco mosaic virus (TMV) infection [15].…”

Silencing Autophagy-Related Gene 2 (ATG2) Results in Accelerated Senescence and Enhanced Immunity in Soybean

“…It has been demonstrated that the selective autophagy plays central roles in removing protein aggregates [9][10][11][12] and damaged organelles [13][14][15][16][17][18][19] under stress conditions. In addition, selective autophagy also plays a crucial role in the clearance of invading pathogens, such as bacteria, viruses, and fungi [20][21][22][23][24][25].…”