The interaction between Turnip crinkle virus p38 and Cucumber mosaic virus 2b and its critical domains

Cross protection is a common phenomenon among closely related strain viruses in co-infected plants. However, unrelated viruses, Turnip crinkle virus (TCV) and Cucumber mosaic virus (CMV), also show an antagonistic effect in co-infected Arabidopsis plants. In many cases, viral suppressors of RNA silencing (VSRs) have important roles in the interactions between viruses in mixed infections. CMV 2b and TCV p38 are multifunctional proteins and both of them are well characterized VSRs and have important roles in operation synergistic interactions with other viruses. Here, we demonstrated antagonistic effects of TCV toward CMV and showed that RNA silencing-mediated resistance protein, RCY1 and TCV-interacting protein (TIP) of Arabidopsis plants did not affect this antagonism effect. We further showed that TCV p38 and CMV 2b could interact with each other in vivo but not in vitro. Further mutational analysis showed that C-terminal of 2b and middle domains of p38 had more important roles in the interaction between the two viruses.