Experimental evolution of resistance against Bacillus thuringiensis in the insect model host Galleria mellonella results in epigenetic modifications

ABSTRACTEpigenetic mechanisms have been proposed to translate environmental stimuli into heritable transgenerational phenotypic variations that can significantly influence natural selection. An intriguing example is exposure to pathogens, which imposes selection for host resistance. To test this hypothesis, we used larvae of the greater wax moth Galleria mellonella as model host to experimentally select for resistance to Bacillus thuringiensis (Bt), the most widely used bacterial agent for the biological control of pest insects. To determine whether epigenetic mechanisms contribute to the evolution of resistance against pathogens, we exposed G. mellonella larvae over 30 generations to spores and crystals mix of Bt and compared epigenetic markers in this selected line, exhibiting almost 11-fold enhanced resistance against Bt, to those in a non-selected control population. We found that experimental selection influenced acetylation of specific histones and DNA methylation as well as transcription of genes e...