Antiviral modes of action of the novel compound GLY‐15 containing pyrimidine heterocycle and moroxydine skeleton against tobacco mosaic virus

Abstract BACKGROUND Plant virus diseases are difficult to prevent and control, causing serious economic losses to the agricultural production world. To develop new pesticides with antiviral activity, a serial of compounds containing the structure of pyrimidine and moroxydine were synthesized, among which GLY‐15 exhibited good antiviral activity against tobacco mosaic virus (TMV), while the mechanism of antiviral activity remains to be clarified. RESULTS GLY‐15 treatment significantly inhibited the formation of necrotic spots caused by TMV in Nicotiana glutinosa , and effectively suppressed the systemic transportation of TMV expressing a reporter gene (p35S‐30B:GFP) in N. benthamiana and markedly reduced the accumulation of a movement deficient TMV in plants as well as viral RNA accumulation in tobacco protoplasts. The results of RNA sequencing showed that GLY‐15 induced significant differential expression of genes or pathways involved in the stress response, defense response and signal transduction, phytohormone response and metabolism. Among them, real‐time quantitative PCR validated that the expression of 12 critical genes such as heat shock protein, receptor kinase, cell‐wall‐related protein, disease‐related protein and glucan endo‐1,3‐β‐glucosidase were significantly up‐regulated. In addition, GLY‐15 triggered reactive oxygen species (ROS) production and induced the activity of several crucial defense related enzymes in plants. The results of molecular docking showed potential binding ability of GLY‐15 with TMV helicase and the coat protein. CONCLUSION This study provide valuable insights into antiviral mechanism of action for GLY‐15, which is expected to be applied as a pesticide for the management of plant viruses. © 2022 Society of Chemical Industry.