This COVID-19 event has been created by a combination of computational inference (see https://reactome.org/documentation/inferred-events) from SARS-CoV-1 data and manual curation, as described in the summation for the overall SARS-CoV-2 infection pathway.
Nucleoprotein (N) is ADP-ribosylated. The modification is maintained both in the cell and in virions (Grunewald et al, 2018). Members of the protein mono-ADP-ribosyltransferase (PARP) enzyme family are thought to catalyze this reaction (Fehr et al. 2020)