The active-toxin form of Cry1Ac or Cry2Ab was fed to L. hesperus in an artificial diet. Biochemical and immunohistochemical methods were used to determine the distribution of ingested toxin. Our results showed that the toxins were not feeding deterrents. Cry1Ac and Cry2Ab were both ingested; some was absorbed into the hemolymph as a holoprotein, but most was excreted. SDS-PAGE analysis of Cry1Ac incubations with salivary gland homogenate showed a small decrease in the molecular weight. Little or no additional proteolytic processing of the toxins occurred within the digestive system of L. hesperus. Cry1Ac passing through the alimentary canal retained toxicity to lepidopteran larvae. Immunohistochemical images showed little or no association of Cry1Ac with L. hesperus tissues. However, in contrast, strong association with gut and hemolymph was observed for Cry2Ab. Signal was found associated with the midgut brush-border microvilli and cellular outlines within the hemolymph and fat body.
Species 1: Heteroptera Miridae Lygus hesperus (western tarnished plant bug)
Keywords: digestion, histology
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA