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Bacterial pathogen epidemiology using lux/gfp markers - HH2306SX

The ability of the UK horticulture industry to satisfy market demands and compete effectively against imports depends on the ability of growers to produce high quality produce which is free from pests and diseases.
Bacterial diseases present particular problems for growers as, unlike fungal diseases, there are few, if any, opportunities for chemical control and by the time disease is seen in the field it is too late to apply other control options. A neglected area of study in the case of seed borne bacterial diseases has been the process by which seeds become infected or contaminated. The use of bioluminescent (lux) and fluorescent (gfp) genetic marker systems provide opportunities for in situ tracking and monitoring of populations and individual cells of specific bacterial strains. The main objective of this project is to use lux/gfp genetic marker systems to follow the transmission of bacterial plant pathogens from mother plant to seed, the location of and distribution of inoculum on infected/contaminated seed and its relationship with seed to seedling transmission. Studies will be done in the Brassica/Xanthomonas pathosystem as this represents the most important bacterial disease in field vegetable production, and because well characterised pathogen strains, host material, inoculation methods, etc. are readily available from previous MAFF-funded work. The results of this work will provide new insights into the biology and epidemiology of seed-borne bacterial diseases and may lead to the identification of novel targets for disease control, or improvement of existing strategies. Ultimately these results may lead to improved competitiveness of UK growers, addressing MAFF policy objective to reduce and improve the quality and availability of crop protection measures whilst optimising pesticide use.

Bacteriophages are viruses that infect bacteria resulting in lysis and death of the host bacterium. They offer the potential for an environmentally safe and sustainable novel approach to the bio-control of bacterial plant diseases. As a first step in determining the potential of this approach we will attempt to isolate and characterise a range of bacteriophage strains which infect and lyse the brassica black rot pathogen (Xanthomonas campestris pv. campestris). These strains will then form the basis of further work to examine the potential utility of phage-therapy for practical disease control.

1. Produce lux/gfp-marked strains of Xanthomonas campestris pv. campestris (Xcc) which do not differ in pathogenicity from wild-type strains
2. Select host lines and validate detection systems
3. Examine the route of transmission of Xcc from mother-plant to seed
4. Examine the location and distribution of Xcc on infected/contaminated seed
5. Examine the route of transmission from seed to seedling
6. Isolation of bacteriophages of Xcc
7. Characterisation of bacteriophages of Xcc

Project Documents
• Final Report : Bacterial pathogen epidemiology using lux/gfp markers   (465k)
Time-Scale and Cost
From: 2001

To: 2004

Cost: £346,944
Contractor / Funded Organisations
Horticulture Research International
Disease Control              
Pesticide use              
Fields of Study