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Virus-plant dynamics change over time, influencing interactions between plants and insect vectors. However, the signaling pathways and regulators that control these temporal responses remain largely unknown. In this study, we used insect performance and preference bioassays, RNA-Seq, and genetic tools to identify underlying mechanisms mediating temporal variation in plant-virus-vector interactions. We show that settlement and fecundity of the aphid vector,Myzus persicae, is increased on potato virus Y (PVY)-infectedNicotiana benthamianaplants two weeks after inoculation but not after six weeks. RNA-Seg analysis revealed transcripts related to plant defense and amino acid biosynthesis are upregulated in response to PVY infection and down regulated in response to aphid herbivory, and these patterns changed over time. Based on this analysis we identified a sesquiterpene synthase gene, terpene synthase 1 (NbTPS1), that is upregulated early in PVY infection, but not at later infection time points. Using virus-induced gene silencing and transient overexpression inN. benthamianawe demonstrate that PVY induction ofNbTPS1is required for increased aphid attraction to PVY-infected plants in the early stages of infection. Taken together, PVY temporally regulates transcriptional pathways related to plant defense responses and volatile organic compounds that influence aphid vector performance and preference.
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The Potyviral Protein 6K1 Reduces Plant Proteases Activity during Turnip mosaic virus Infection
Potyviral genomes encode just 11 major proteins and multifunctionality is associated with most of these proteins at different stages of the virus infection cycle. Some potyviral proteins modulate phytohormones and protein degradation pathways and have either pro- or anti-viral/insect vector functions. Our previous work demonstrated that the potyviral protein 6K1 has an antagonistic effect on vectors when expressed transiently in host plants, suggesting plant defenses are regulated. However, to our knowledge the mechanisms of how 6K1 alters plant defenses and how 6K1 functions are regulated are still limited. Here we show that the 6K1 from Turnip mosaic virus (TuMV) reduces the abundance of transcripts related to jasmonic acid biosynthesis and cysteine protease inhibitors when expressed in Nicotiana benthamiana relative to controls. 6K1 stability increased when cysteine protease activity was inhibited chemically, showing a mechanism to the rapid turnover of 6K1 when expressed in trans. Using RNAseq, qRT-PCR, and enzymatic assays, we demonstrate TuMV reprograms plant protein degradation pathways on the transcriptional level and increases 6K1 stability at later stages in the infection process. Moreover, we show 6K1 decreases plant protease activity in infected plants and increases TuMV accumulation in systemic leaves compared to controls. These results suggest 6K1 has a pro-viral function in addition to the anti-insect vector function we observed previously. Although the host targets of 6K1 and the impacts of 6K1-induced changes in protease activity on insect vectors are still unknown, this study enhances our understanding of the complex interactions occurring between plants, potyviruses, and vectors.
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- PAR ID:
- 10384840
- Date Published:
- Journal Name:
- Viruses
- Volume:
- 14
- Issue:
- 6
- ISSN:
- 1999-4915
- Page Range / eLocation ID:
- 1341
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/v14061341
