Binding of Bt Cry toxins to lepidopteran midgut aminopeptidase N and the relationship between their interactions with Bt resistance

With the wide application and popularization of Bt Cry crop, the resistance of target pests against Bt Cry crop has become the focus of studies on its ecological safety. Aminopeptidase N (APN) is one of Bt-toxin receptor proteins located in brush border membrane vesicles (BBMV) of insect midgut. Its binding capability with Bt Cry toxin determines the toxin′s insecticidal spectrum and insect Bt resistance. This paper systemically reviews the progress of researches on APN structural characteristics and classfication, the binding feature, binding sites and interactions mechanism of Bt Cry toxin and APN as well as Bt resistance resulting from APN mutations.