Defra - Department for Environment, Food and Rural Affairs.

Science Search

Science and Research Projects

Return to Science Search homepage   Return to Project List

Identification and characterisation of novel toxins for use in the control of insect pests in horticulture. - HH1829SFV

The project aims to characterise, both genetically and through host range studies, novel bacterial toxins with pesticidal activity, for use in insect pest control in horticulture. The research will focus on a new group of insect-active toxins, produced by strains of bacteria belonging to the two genera Xenorhabdus and Photorhabdus. Preliminary characterisation of these toxins has shown them to be of great scientific and practical interest, with good activity to a range of insect species belonging to the orders Lepidoptera, Diptera and Coleoptera, all key pest groups in UK horticulture. To obtain a greater understanding of these novel toxins, genetic studies will determine the factors responsible for toxin complexity and mode of action. This will also enable methods to be developed for use in the identification, isolation and characterisation of further related toxins. Insect assays with the purified toxins will determine the range of key horticultural pests against which these toxins are active. The data obtained on the diversity and host range of these novel toxins should lead to the development of new and specific toxins for use in pest control in horticulture as either sprayable products or new genes for use in the construction of transgenic plants. The use of bacterial toxins with defined host range for insect control in UK horticulture would provide more sustainable control of pests through the provision of a wider choice of control options including possible replacements for organophosphate insecticides, not have harmful effects on biodiversity and enable the competitive production of horticultural produce in an environmentally benign way that satisfies customers.
The overall objective is to determine the diversity of insect-active toxins from the bacteria Xenorhabdus species and Photorhabdus luminescens and their potential to control arthropod pests of horticulture. The specific objectives to achieve this are:

01. To determine the genetic diversity of toxins from 25 insect active isolates of bacteria from diverse geographical locations.

02. Match the genetic diversity of toxins to their biological activity and specificity using insect species from each of three orders.

03. Purify and characterise the toxins from the six most active isolates of bacteria.

04. Determine the relative biological activity and specificity of the six purified toxins
to a wide spectrum of pests of horticultural importance (seven species from five orders)

05. Clone novel toxin genes from two strains with greatest biological activity

06. Identify the preliminary mode of action of the toxin to insect cell lines and purified gut cells.
Project Documents
• Final Report : final report   (1377k)
Time-Scale and Cost
From: 1999

To: 2003

Cost: £429,179
Contractor / Funded Organisations
Horticulture Research International
Biological Control              
Organic Farming              
Pest Control              
Fields of Study