BSPP News 31 Autumn 1997 - Online Edition

The Newsletter of the British Society for Plant Pathology
Number 31, Autumn 1997

Metabolic Pathways of the Diseased Potato

A lot of information has been published on resistance mechanisms relating to a number of plant/pathogen interactions. I have summarised some of the information which is relevant for potato into a chart showing the metabolic pathways involved. Those of you interested in resistance mechanisms will recognise most of the key features and may find it a useful source of information or a useful place to direct new students. The chart may also be useful for plant molecular biologists interested in genetically modifying the potato in order to understand some of the interactions taking place in a diseased potato.

The chart contains a lot of information absent from metabolic pathways of `normal' plant and animal cells and includes the biosynthesis of phenylpropanoids, sesquiterpene phytoalexins, glycoalkaloids, ethylene, fatty acid degradation, lipid peroxidation, free radical production, and some basic information on post-translational modification including protein phosphorylation and prenylation.

The chart was drawn using Adobe Illustrator and converted into a PDF file (Portable Document File) which can be viewed on the Internet from To view the file you need Adobe Acrobat Reader software but this is available free over the Internet. I have provided a link from the web page to the Adobe website. It can take a while to download the Acrobat Reader from the USA so ask your colleagues if they have a version first. PDF files are becoming more common on the Internet so it is worth the effort to obtain the Acrobat Reader software.

The metabolic pathways chart provides too much information to be printed on A3 or A4 paper but if you have access to a larger printer format then you can print your own wall chart. Once printed as a wall chart the complexity of the host's response to infection becomes even more apparent as does the lack of information on certain biosynthetic routes e.g. the enzymes involved in sesquiterpene phytoalexin biosynthesis. I intend to up-date the chart as relevant information is published.

Gary Lyon
Scottish Crop Research Institute 

Science and Plants for Schools

SAPS works with teachers to promote plant science and molecular biology in schools. We develop teaching resources for all ages and levels and runs workshops for teachers to share these developments and ideas.

Some of the ideas for primary schools involve the making and looking after of portable ponds, compost and ecocolumns, and growing the rapid cycling brassicas, which were developed in the USA by Paul Williams and his team. These versatile plants also offer excellent material for genetic studies as part of an A level investigation, as they cycle seed to seed in 35 days, which fits comfortably into a school half term. Simple cheap apparatus and ideas have also been developed to illustrate the principles of photosynthesis, to demostrate the importance of soil nutrients, and to investigate tropisms, to name a few.

More recent developments include producing a CDROM, "Investigating Plant Science", simple tissue culture techniques which can be undertaken without the use of an air bench, and a DNA kit which allows students to extract plant DNA. Room temperature stable restriction enzymes and Lambda DNA and allow youngsters to cut and run plant and lambda DNA gels. Safety features highly in all these protocols, nontoxic DNA stains have been chosen, and battery run mini gel tanks have all been specially developed for this work, in collaboration with the National Centre for Biological Education at Reading.

One of our latest projects involves collaboration with another Gatsby funded programme to develop and test cheap equipment to allow more such work to take place the low cost microfuge and shaker, likely to cost well below £100 and £50 are currently being trialled. All the SAPS material is now available on the WWW and the site is fully searchable. We offer a Question and Answer service to teachers and pupils, and welcome input and articles from scientists. The URL is:

The core funding for SAPS comes from the Gatsby Foundation, and we thank the BSPP Innovation Fund for a grant of £2500 towards developing plant pathology protocols for schools. This money will be used to develop Brassica pathology systems suitable for schools, which will form a link between the rapid cycling brassicas and the DNA work. This work will take place at the John Innes Centre and at SAPS, Homerton College, Cambridge.

Science and Plants in Schools develops experiments with rapid-cycling brassicas,
for age ranges from primary classes to A-level

Initially we will be looking at four pathogens, Leptosphaeria maculans, Fusarium oxysporum conglutinans, Albugo candida, and Plasmodiophora brassicae, but plan to select two of these for use in schools. If anyone has good isolates which differ in pathogenicity, or Brassica material with clear cut resistant / susceptible reactions to these fungi, please contact Paul Nicholson (JIC; or Mary MacDonald (SAPS; mvm1000@ We have a tight one year deadline to meet, and plan to have a prototype school kit ready for the International Congress next year.

Mary MacDonald
SAPS, Homerton College, Cambridge