P3 and NIa-Pro of Turnip Mosaic Virus Are Independent Elicitors of Superinfection Exclusion

Superinfection exclusion (SIE) is an antagonistic interaction between identical or closely related viruses in host cells. Previous studies by us and others led to the hypothesis that SIE was elicited one more proteins encoded genomes of primary viruses. Here, we tested this using Turnip mosaic virus (TuMV), a member genus Potyvirus family Potyviridae, with significant economic consequences. To end, individual TuMV-encoded were transiently expressed cells Nicotiana benthamiana leaves, followed challenging them modified TuMV expressing green fluorescent protein (TuMV-GFP). Three days after TuMV-GFP delivery, these examined for replication-dependent expression GFP. Cells P1, HC-Pro, 6K1, CI, 6K2, NIa-VPg, NIb, CP permitted efficient GFP, suggesting failed block replication superinfecting TuMV-GFP. By contrast, N. P3 NIa-Pro did not express visible GFP fluorescence, both could elicit potent against The elicitor activity further confirmed their heterologous from different potyvirus, potato A (PVA). Plants systemically infected PVA variants blocked subsequent infection +1-frameshift mutation cistrons facilitated superinfection TuMV-GFP, proteins, but RNA, are involved activity. Additionally, deletion mutagenesis identified amino acids 3 200 352 40 181 242 as essential elicitation. Collectively, our study demonstrates encodes two spatially separated act independently exert on TuMV. These results lay foundation mechanistic interrogations virus.