P-232 - Antiviral Jacalin-like lectin gene comprises a layer of nonhost resistance that constraints the host range of plant viruses

Host range varies widely among plant pathogens, with some pathogens infecting a wide range of plant species, while others infect only certain plant species. The resistance exhibited by the nonhost plant species is called nonhost resistance (NHR) and various resistance genes involved in NHR have been isolated. However, since most resistance genes remain single plant-pathogen relationships, it remains unclear to what extent NHR limits the host range of the pathogen. Potexviruses are filamentous plant viruses with single-stranded RNA genomes, and have more than 40 species isolated from a wide variety of plants, indicating a broad host range for the entire virus genus. In contrast, there are very few reported outbreaks of potexviruses in cruciferous plants, indicating that they have developed an NHR against the entire potexviruses, but the details are unknown. In this study, we report that a non-NLR-type antiviral resistance gene, JAX1, is genetically and functionally conserved in cruciferous plants. Inoculation tests and JAX1 expression analysis revealed a correlation between the resistance to a potexvirus and JAX1 ortholog expression. Furthermore, we found that the JAX1 ortholog of a particular cruciferous plant contributes to NHR against a potexvirus. Our findings suggest that JAX1 acts as an NHR factor in a cruciferous plant and forms a conserved layer of antiviral resistance which limits the host range of potexviruses in cruciferous plants.