A plant defensive cystatin (soyacystatin) targets cathepsin L-like digestive cysteine proteinases (DvCALs) in the larval midgut of western corn rootworm (Diabrotica virgifera virgifera)

Reference Report for SoyBase121101433

Title:	A plant defensive cystatin (soyacystatin) targets cathepsin L-like digestive cysteine proteinases (DvCALs) in the larval midgut of western corn rootworm (Diabrotica virgifera virgifera)
Authors:	Koiwa, H., Shade, R.E., Zhu-Salzman, S.K., Paino D'Urzo, M., Murdock, L.L., Bressan, R.A., Hasegawa, P.M.
Source:	FEBS Lett. 2000, 471(1):67-70
Abstract:	Feeding bioassay results established that the soybean cysteine proteinase inhibitor N (soyacystatin N, scN) substantially inhibits growth and development of western corn rootworm (WCR), by attenuating digestive proteolysis (Zhao, Y. et al. (1996) Plant Physiol. 111, 1299-1306). Recombinant scN was more inhibitory than the potent and broad specificity cysteine proteinase inhibitor E-64. WCR digestive proteolytic activity was separated by mildly denaturing SDS-PAGE into two fractions and in-gel assays confirmed that the proteinase activities of each were largely scN-sensitive. Since binding affinity to the target proteinase (Koiwa, H. et al. (1998) Plant J. 14, 371-380) governs the effectiveness of scN as a proteinase inhibitor and an insecticide, five peptides (28-33 kDa) were isolated from WCR gut extracts by scN affinity chromatographic separation. Analysis of the N-terminal sequence of these peptides revealed similarity to a cathepsin L-like cysteine proteinase (DvCAL1, Diabrotica virgifera virgifera cathepsin L) encoded by a WCR cDNA. Our results indicate that cathepsin l orthologs are pivotal digestive proteinases of WCR larvae, and are targets of plant defensive cystatins (phytocystatins), like scN.

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