Abstract
Vegetative insecticidal proteins (Vips) are widely used in pest
management, but Vip resistance is a big threat. DNA methylation plays
important roles in regulating the response of biological organisms to
environmental stress. In this study, DNA methylation map was developed
for fall armyworm (FAW, Spodoptera frugiperda), and its function in
regulating FAW Vip3Aa resistance was explored. FAW was screened by
Vip3Aa for 10 generations, and bioassays indicated that Vip3Aa
resistance increased trans-generationally. Based on the comparison of
DNA methylation maps between Vip3Aa-resistant and -susceptible strains
showed that gene body methylation was positively correlated with its
expression. Moreover, the study demonstrated that a reduction in the
methylation density within the gene body of a 3’5’-cyclic nucleotide
phosphodiesterase gene resulted in decreased expression and increased
resistance of FAW to Vip3Aa, which was validated through RNAi
experiments. The mechanism of Vip3Aa resistance will improve the
understanding of DNA methylation and its function in lepidoptera and
provide a new perspective for making strategies to pest management.