Inhibition of Helicoverpa armigera gut pro-proteinase activation in response to synthetic protease inhibitors

Parde, Vinod Dadarao and Sharma, H C and Kachole, M S (2012) Inhibition of Helicoverpa armigera gut pro-proteinase activation in response to synthetic protease inhibitors. Entomologia Experimentalis et Applicata, 142 (2). pp. 104-113. ISSN 1570-7458

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Abstract

Protease inhibitors play an important role in host plant defence against herbivores. However, insects have the ability to elevate the production of proteinases or resort to production of a diverse array of proteinases to offset the effect of proteinase inhibitors. Therefore, we studied the inhibition of pro-proteinase(s) activation in the midgut of the polyphagous pest Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in response to protease inhibitors to develop appropriate strategies for the control of this pest. Gelatin coating present on X-ray film was used as a substrate to detect electrophoretically separated pro-proteinases and proteinases of H. armigera gut extract on native- and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Six activated pro-proteinase bands were detected in H. armigera gut lumen, which were partially purified and characterized using substrate assays. Activated H. armigera midgut pro-proteinase(s) showed activity maxima at pH 8 and 10, and exhibited optimal activity at 40 °C. The activation of H. armigera gut pro-proteinase isoforms was observed in the fraction eluted on benzamidine-sepharose 4B column. Purification and substrate assay studies revealed that 23–70 kDa polypeptides were likely the trypsin/chymotrypsin-like pro-proteinases. Larvae of H. armigera fed on a cocktail of synthetic inhibitors (antipain, aprotinin, leupeptin, and pefabloc) showed maximum activation of pro-proteinases compared with the larvae fed on individual inhibitors. The implications of these results for developing plants expressing proteinase inhibitors for conferring resistance to H. armigera are discussed.

Item Type:	Article
Divisions:	UNSPECIFIED
CRP:	UNSPECIFIED
Uncontrolled Keywords:	Chymotrypsinogen;plant protease inhibitors;polypeptides;transgenic resistance;trypsinogen;Lepidoptera;Noctuidae;cotton bollworm
Subjects:	Mandate crops > Chickpea Others > Fertilizer Applications Others > Entomology
Depositing User:	Mr Sanat Kumar Behera
Date Deposited:	17 Jan 2012 05:43
Last Modified:	05 Oct 2012 10:31
URI:	http://oar.icrisat.org/id/eprint/5334
Official URL:	http://dx.doi.org/10.1111/j.1570-7458.2011.01209.x
Projects:	UNSPECIFIED
Funders:	UNSPECIFIED
Acknowledgement:	The authors thank the staff of entomology for supplying H. armigera culture for bioassays. We also thank Dr. K.L. Sahrawat for his valuable comments on the manuscript.
Links:	Author

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