Alpha‐momorcharin enhances Nicotiana benthamiana resistance to tobacco mosaic virus infection through modulation of reactive oxygen species

Alpha‐momorcharin (α‐MMC), a member of the plant ribosomal inactivating proteins (RIPs) family, has been proven to exhibit important biological properties in animals, including antiviral, antimicrobial, and antitumour activities. However, the mechanism by which α‐MMC increases plant resistance to viral infections remains unclear. To study the effect of α‐MMC on plant viral defence and how α‐MMC increases plant resistance to viruses, recombinant DNA and transgenic technologies were employed to investigate the role of α‐MMC in Nicotiana benthamiana resistance to tobacco mosaic virus (TMV) infection. Treatment with α‐MMC produced through DNA recombinant technology or overexpression of α‐MMC mediated by transgenic technology alleviated TMV‐induced oxidative damage and reduced the accumulation of reactive oxygen species (ROS) during TMV‐green fluorescent protein infection of N. benthamiana. There was a significant decrease in TMV replication in the upper leaves following local α‐MMC treatment and in α‐MMC‐overexpressing plants relative to control plants. These results suggest that application or overexpression of α‐MMC in N. benthamiana increases resistance to TMV infection. Finally, our results showed that overexpression of α‐MMC up‐regulated the expression of ROS scavenging‐related genes. α‐MMC confers resistance to TMV infection by means of modulating ROS homeostasis through controlling the expression of antioxidant enzyme‐encoding genes. Overall, our study revealed a new crosstalk mechanism between α‐MMC and ROS during resistance to viral infection and provides a framework to understand the molecular mechanisms of α‐MMC in plant defence against viral pathogens.