In this study, we observed a dynamic reprogramming of bivalency in a group of Fg genes during its successful infection on wheat and demonstrated that BCG1 gene converts from an active H3K4me3 to a bivalent chromatin state by the specific gain of H3K27me3 for rapid epigenetic silencing of BCG1 to avoid host immune system recognition. This evidence concerns the gene MAGED2 and infection.