Silence of APN2 gene reveals the trade-offs for acquiring Cry1Ac resistance in Plutella xylostella

In this study, Aminopeptidase-N 2 (APN2), a Cry toxin receptor gene of P. xylostella, was knocked down by RNA interference, resulting in improved resistance to Cry1Ac. It was also found that the APN2-knocked-down P. xylostella had significantly higher larval mortality than the control, while the pupation rate, pupal weight, eclosion rate, fecundity(egg/female), hatchability, and female adult longevity were significantly lower than that of the control. These results illustrate that if Cry1Ac resistance was obtained only through the reduction of APN2 expression, P. xylostella would need to incur some fitness costs for it.