Fig. 7

Heterochromatin formation promotes antimicrobial responses through imd pathway mediated expression of AMPs, including DptA. Increased HP1a-mediated heterochromatin formation in the fat body promotes resistance to systemic P. aeruginosa infection. Before infection, fat body HP1a-mediated heterochromatin formation induces overexpression of imd pathwayrelated AMPs. Mechanistically, upon P. aeruginosa infection, increased heterochromatin formation in the fat body promotes antimicrobial responses through imd pathway mediated DptA expression. Moreover, upon P. aeruginosa infection, the time-dependent, physiological heterochromatin levels are tightly regulated via epigenetic changes: downregulated in the early stage of P. aeruginosa infection and then upregulated in the middle stage. Increased fat body heterochromatin formation improves antimicrobial responses against P. aeruginosa infection and promotes host survival