Progress of studies on insect midgut aminopeptidase N serving as Bacillus thuringiensis insecticidal crystal protein toxin receptor

The changes of aminopeptidase N(APNs) in site concentration and structure are one of major resistance mechanisms of insects to Bacillus thuringiensis (Bt.) The authors reviewed the progress of research on APN receptor. A few types of APNs exist on the midgut brush border membrane of each species.They are highly homologous,and some of them serve as Bt Cry1A family toxin receptor.APNs maybe bind to different Bt toxins, and confer different level of susceptibility of Bt toxin to the insect.A few of mutations at the coding region of APN genes were found in some Bt resistant insects species.