Characterisation of midgut digestive proteases from the maize stem borer Busseola fusca

George, D, Ferry, N ORCID: https://orcid.org/0000-0003-3728-4302, Back, E and Gatehouse, A 2008, 'Characterisation of midgut digestive proteases from the maize stem borer Busseola fusca' , Pest Management Science, 64 (11) , pp. 1151-1158.

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Abstract

BACKGROUND: Insect damage is a major constraint on maize production. Control of Busseola fusca (Fuller) in sub-Saharan Africa is relatively ineffective; the major larval digestive enzymes were characterised with a view to developing future control strategies. RESULTS: Using BODIPY-FL Casein, maximal activity was at pH 9.5, with six protease forms visualised by gelatin-PAGE. Synthetic substrates and diagnostic inhibitors demonstrated the presence of serine proteases. Chymostatin was a potent inhibitor of general proteolysis (90%), providing strong evidence for the presence of chymotrypsin; it also caused significant inhibition (>95%) with SA2PFpNA as substrate. The I50 values for chymostatin with casein and SA2PFpNA were 0.0075 μM and 0.06 μM respectively. Z-Phe-Arg-pNA activity was inhibited by chymostatin and TLCK (50 and 30% respectively), suggesting the presence of trypsin-like activity. BApNA hydrolysis was also strongly inhibited by chymostatin and TLCK (92 and 75%), suggesting trypsin activity, while SBBI, PMSF, pepstatin and E-64 had no significant effect. Interestingly, SBBI (I50 = 0.39 μM) and SBTI both inhibited general proteolysis by approximately 70%, suggesting that SBBI’s dual inhibitory role makes this inhibitor a potentially useful candidate for expression in maize for control of B. fusca. CONCLUSION: These results provide a basis for the rational design of insect-resistant transgenic maize expressing protease inhibitors.

Item Type:	Article
Themes:	Built and Human Environment
Schools:	Schools > School of Environment and Life Sciences
Journal or Publication Title:	Pest Management Science
Publisher:	John Wiley & Sons
Refereed:	Yes
ISSN:	1526-498X
Depositing User:	Dr Natalie Ferry
Date Deposited:	06 Oct 2011 13:35
Last Modified:	16 Feb 2022 12:46
URI:	https://usir.salford.ac.uk/id/eprint/17955

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