Transcriptional regulation in cowpea bruchid guts during adaptation to a plant defence protease inhibitor.
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.
Moon
J
J
Department of Entomology, Texas A&M University, College Station, TX 77843, USA.
Salzman
R A
RA
Ahn
J-E
JE
Koiwa
H
H
Zhu-Salzman
K
K
D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002401:Cathepsin B / Q000235:genetics; D001517:Coleoptera / Q000235:genetics / Q000378:metabolism*; D015891:Cystatins / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000378:metabolism*; D018076:DNA, Complementary / Q000235:genetics; D004064:Digestive System / Q000378:metabolism*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D007814:Larva / Q000378:metabolism; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D030262:Soybean Proteins
D015891:Cystatins; D015853:Cysteine Proteinase Inhibitors; D018076:DNA, Complementary; D030262:Soybean Proteins; C414109:scN protein, soybean; D002401:Cathepsin B