Transcriptional regulation in cowpea bruchid guts during adaptation to a plant defence protease inhibitor

Insect Mol Biol. 2004 Jun;13(3):283-91. doi: 10.1111/j.0962-1075.2004.00485.x.


Cowpea bruchid, when fed on a diet containing the soybean cysteine protease inhibitor soyacystatin N (scN), activates an array of counter-defence genes to adapt to the negative effects of the inhibitor and regain its normal rate of feeding and development. A collection of 1920 cDNAs was obtained by differential subtraction with cDNAs prepared from guts of the 4th instar larvae of scN-adapted (reared on scN-containing diet) and scN-unadapted (reared on regular scN-free diet) cowpea bruchids. Subsequent expression profiling using DNA microarray and Northern blot analyses identified ninety-four transcript species from this collection that are responsive to dietary scN. scN-adapted insects induced genes encoding protein and carbohydrate digestive enzymes, probably to help meet their carbon and nitrogen requirements. Up-regulation of antimicrobial and detoxification protein genes may represent a generalized defence response. Genes down-regulated by scN reflected physiological adjustments of the cowpea bruchids to scN challenge. A large portion of the responsive genes, presumably involved in carrying out the counter-defence response, were of unknown function. The full-length cDNA of an scN-inducible cathepsin B-like cysteine protease was obtained. Its transcriptional response to scN during larval development contrasts with the pattern of the cathepsin L family, the major digestive enzymes. These results suggest cathepsin B-like cysteine proteases may play a crucial role in cowpea bruchid adaptation to dietary scN.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adaptation, Physiological*
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Blotting, Northern
  • Cathepsin B / genetics
  • Coleoptera / genetics
  • Coleoptera / metabolism*
  • Cystatins / metabolism*
  • Cysteine Proteinase Inhibitors / metabolism*
  • DNA, Complementary / genetics
  • Digestive System / metabolism*
  • Gene Expression Profiling
  • Gene Expression Regulation*
  • Larva / metabolism
  • Molecular Sequence Data
  • Oligonucleotide Array Sequence Analysis
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Soybean Proteins


  • Cystatins
  • Cysteine Proteinase Inhibitors
  • DNA, Complementary
  • Soybean Proteins
  • scN protein, soybean
  • Cathepsin B