title: Developmental studies of transgenic maize expressing Cry1Ab on the African stem borer, Busseola fusca; effects on midgut cellular structure.
abstract: BACKGROUND
  Busseola fusca is a major pest of maize in Africa but unfortunately is difficult to control using chemical insecticides. Insect-resistant transgenic crops may provide an alternative viable strategy to control this pest.
  
  
  RESULTS
  Recombinant Cry1Ab (1%) reduced larval weight by 60% over the trial period, while larval weight in the control group increased by 25%; no effects on mortality were observed. Insect survival, developmental rate and pupal and adult weight were significantly reduced (P < 0.05) on maize expressing Cry1Ab (MON810) compared with the non-transformed parental line. These differences were more pronounced with second-instar larvae than with third-instar larvae. Leaf area consumed by Bacillus thuringiensis (Bt)-fed larvae was significantly lower (0.5 cm(2) larva(-1) day(-1)) compared with the area consumed by control-fed insects (3.3 cm(2) larva(-1) day(-1)). EM studies revealed that consumption of Bt maize deleteriously affected gut integrity. Effects were observed in columnar cells of the midgut epithelium, with the cytoplasm becoming highly vacuolated; the microvilli were disorganised, the mitochondria were abnormal and there was an increase in the number of lysosomal bodies. The rough endoplasmic reticulum had also become dilated.
  
  
  CONCLUSIONS
  This study confirms the potential for Bt maize, when used as part of an IPM programme, for control of B. fusca.
authors.affiliation: School of Biology, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Derick M
authors.initials: DM
authors.lastname: George
authors.forename: F Claire
authors.initials: FC
authors.lastname: Rind
authors.forename: Mark W
authors.initials: MW
authors.lastname: Bendall
authors.forename: Mark A
authors.initials: MA
authors.lastname: Taylor
authors.forename: Angharad M R
authors.initials: AM
authors.lastname: Gatehouse
mesh_terms: D000349:Africa; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D004731:Endotoxins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D041981:Gastrointestinal Tract / Q000033:anatomy & histology / Q000166:cytology / Q000254:growth & development; D015870:Gene Expression; D006460:Hemolysin Proteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D007300:Insect Control / Q000379:methods*; D007306:Insecticides / Q000494:pharmacology; D009036:Moths / Q000033:anatomy & histology* / Q000187:drug effects / Q000254:growth & development* / Q000502:physiology; D010572:Pest Control, Biological / Q000379:methods; D010935:Plant Diseases / Q000469:parasitology*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism / Q000469:parasitology*; D003313:Zea mays / Q000235:genetics / Q000378:metabolism / Q000469:parasitology*
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis