Fig. 8: A model showing how the distinct viral proteins suppress OsNPR1-mediated antiviral immunity in rice.
From: Different viral effectors suppress hormone-mediated antiviral immunity of rice coordinated by OsNPR1
Left panel: following viral infection, JA and SA levels increase in rice plants23,26,28. JA binds to and promotes the degradation of OsJAZs, and thus releases OsMYC2/3. Meanwhile, an increase in SA leads to the disassociation of OsNPR1 oligomers into monomers to enter the nucleus. OsNPR1 transcriptionally activates JA signaling by destroying the OsJAZ-OsMYC complex to enhance host antiviral immunity. Right panel: to counteract the host antiviral immunity, different types of viral proteins compete with OsMED25 for binding with OsMYC2, to weaken the interaction of OsMYC2 and OsMED258. Simultaneously, these viral proteins directly target OsNPR1 to inhibit OsNPR1-mediated SA-JA crosstalk, leading to the cooperatively attenuation of the JA response, thus subverting the rice antiviral immune responses. Together, our results reveal that different rice viruses generally to regulate key components of SA and JA signaling to overcome host defense, thereby facilitating viral pathogenicity.
