Potential of the bean alpha-amylase inhibitor alpha AI-1 to inhibit alpha-amylase activity in true bugs (Hemiptera)

True bugs (Hemiptera) are an important pest complex not controlled by Bt-transgenic crops. An alternative source of resistance includes inhibitors of digestive enzymes, such as protease or amylase inhibitors. AI-1, an -amylase inhibitor from the common bean, inhibits gut-associated -amylases of bruchid pests of grain legumes. Here we quantify the in vitro activity of -amylases of 12 hemipteran species from different taxonomic and functional groups and the in vitro inhibition of those -amylases by AI-1. -Amylase activity was detected in all species tested. However, susceptibility to AI-1 varied among the different groups. -Amylases of species in the Lygaeidae, Miridae and Nabidae were highly susceptible, whereas those in the Auchenorrhyncha (Cicadellidae, Membracidae) had a moderate susceptibility, and those in the Pentatomidae seemed to be tolerant to AI-1. The species with AI-1 susceptible -amylases represented families which include both important pest species but also predatory species. These findings suggest that AI-1-expressing crops have potential to control true bugs in vivo.