Systemic necrosis induced by overexpression of wheat yellow mosaic virus 14K suppresses the replication of other viruses in Nicotiana benthamiana

Systemic necrosis, induced by plant virus-derived elicitors, is considered as one of the most severe symptoms. It has never been reported that the elicitors encoded by wheat yellow mosaic virus (WYMV) can induce systemic necrosis in plant. In this study, we discovered that the WYMV-encoded 14K protein localized to the endoplasmic reticulum (ER) membrane and triggered a necrotic symptom in Nicotiana benthamiana at 5 days post-infiltration (dpi). Meanwhile, overexpression of WYMV 14K suppressed the replication of tobacco rattle virus (TRV) and potato virus X (PVX). Additionally, deletion of the transmembrane domain and substitution of two non-conserved regions in 14K resulted in the loss of the ability of this protein to induce systemic necrosis. Moreover, the 14K homologous proteins of other bymoviruses failed to induce systemic necrosis. Our results, for the first time, reveal that WYMV 14K induces systemic necrosis and suppresses the replication of other viruses.