Our recent study suggested that infection with Aeromonas hydrophila-induced UPRmt triggered apoptosis of infected fish macrophages by enhancing expression of dnm1l gene which encodes DRP1 protein, therefore results in the fragmentation of the mitochondrial network; and in turn, mitochondrial fission reduced mitochondrial membrane potential (ΔΨm) which prompted release of cyt c in the cytosol leading to the activation of caspase-9 facilitating clearance of the intracellular bacteria (Kumar et al., 2022a). The gene discussed is DNM1L; the disease is infection.