Turnip crinkle virus targets host ATG8 proteins to attenuate antiviral autophagy

Autophagy has emerged as a central player in plant virus disease and resistance. In this study we have addressed potential roles of autophagy in Turnip crinkle virus (TCV) infection. We find that compromised autophagy results in severe disease upon TCV infection, a phenomenon observed earlier for several other viruses as well. We also identified that autophagy provides resistance against TCV by limiting virus accumulation, but the exact mechanism driving this is currently unclear. However, as a viral counter-mechanism, our results reveal that the viral protein P38 can suppress autophagy, likely by sequestering ATG8s. This is a novel strategy for plant viruses, while it has been identified for other pathogen classes. Together, these results broaden our understanding of autophagy in plant virus disease, and strengthens our view of virus-specific adaptation to the autophagy pathway.

Global Plant Virus Disease Pandemics and Epidemics

The world’s staple food crops, and other food crops that optimize human nutrition, suffer from global virus disease pandemics and epidemics that greatly diminish their yields and/or produce quality. This situation is becoming increasingly serious because of the human population’s growing food requirements and increasing difficulties in managing virus diseases effectively arising from global warming. This review provides historical and recent information about virus disease pandemics and major epidemics that originated within different world regions, spread to other continents, and now have very wide distributions. Because they threaten food security, all are cause for considerable concern for humanity. The pandemic disease examples described are six (maize lethal necrosis, rice tungro, sweet potato virus, banana bunchy top, citrus tristeza, plum pox). The major epidemic disease examples described are seven (wheat yellow dwarf, wheat streak mosaic, potato tuber necrotic ringspot, faba bean necrotic yellows, pepino mosaic, tomato brown rugose fruit, and cucumber green mottle mosaic). Most examples involve long-distance virus dispersal, albeit inadvertent, by international trade in seed or planting material. With every example, the factors responsible for its development, geographical distribution and global importance are explained. Finally, an overall explanation is given of how to manage global virus disease pandemics and epidemics effectively.

Modeling the effects of cross-protection control in plant disease with seasonality

Cross-protection in plants has been widely used to control losses caused by virus diseases in the world. Here, a non-autonomous plant-virus disease model was developed including cross-protection. Global dynamics of the model was discussed. Under the quite weak assumptions, integral form conditions were resolved for permanence of the system and extinction of diseases. Furthermore, we looked into the sufficient conditions that plants could be protected against the detrimental effects of infection by an infection with the mild virus isolates. Last, we performed numerical simulations. Our investigations suggested that cross-protection played an important role in controlling the spread of the challenging virus in plants.