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Manipulation of insect immune defences to optimize biological control. - PS2103

The overall objective of the work is to devise improved and/or new crop protection strategies as an
alternative to the use of broad-spectrum neurotoxic pesticides. In particular, biological control strategies which are as reliable and effective as conventional chemical pesticides are desired. By increasing our understanding of insect immune systems and the ways in which certain parasitic wasps disable them (for example using venoms with specific anti-haemocyte factors), we are seeking to develop ways of suppressing key immune defences of insect pests thereby increasing their susceptibility to bio-control agents, such as fungi. As such, this approach has the potential to lead to the deployment of novel bio-control strategies that are target-specific, effective and environmentally friendly. These aims address Defra policy objectives relating to the optimisation or minimization of pesticide use which in turn respond to professional and public concern about the current use of toxic chemicals including organophosphates and other insecticides. It is anticipated that the results generated from this work will be used to forge alliances with relevant companies so that they can be further developed into novel, environmentally sensitive pest management strategies, which will offer the grower realistic levels of efficacy with negligible chance of adverse impact on the environment.
1) To extend the characterization of factors present in P. hypochondriaca venom which manipulate (suppress) immune defences in our model pest insect, L. oleracea. In particular, determine if proteases and/or peptidases are present in venom and if they have any effect on the potency of its anti-haemocyte/immunosuppressive activity. In addition, determine the ‘range’ of the venom anti-haemocyte activity by testing against haemocytes from other insect species, and mammalian cells.

2) To isolate a factor or factors with proven anti-haemocyte activity from the venom and confirm purity using selected biochemical techniques (this involves dissecting the venom glands from as many adult female P. hypochondriaca as possible in order to build up a pool of venom for use in subsequent isolation procedures). In addition, make a preliminary physicochemical characterization of the molecule(s) (particularly with regard to stability), determine N-terminal sequence, and perform a data base homology search. Information gained from this work will help in the design of experiments aimed at elucidating the mechanism of action of the active factor(s) as potential bio-control agents.

3) Using an isolated anti-haemocyte factor with proven immunosuppressive properties, to perform bio-assays to test the concept that targetted suppression of key immune responses can make an insect more susceptible to a suitable bio-control agent (for example, the fungus Beauveria bassiana).

4) To clone the gene(s) of isolated anti-haemocyte factor(s) and determine their DNA sequence(s). This data, and that obtained on the isolated protein(s), are necessary precursors to establishing LINK projects with suitable companies so that the research progresses towards practical uptake.
Project Documents
• Final Report : Manipulation of insect immune defences to optimize biological control.   (717k)
Time-Scale and Cost
From: 2003

To: 2006

Cost: £461,964
Contractor / Funded Organisations
Central Science Laboratory
Arable Farming              
Biological Control              
Crop Pests              
Fields of Study
Pesticide Safety