Nov 14, 2002

Research Projects

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Monitoring of transgenic traits (herbicide, virus, nematode and fungal resistance) in weed and wild beet

(2000 – 2003) RWTH Aachen University; Chair of Biology V

Topic

The aim of the project was to develop and test monitoring concepts for recognising long-term effects of gene transfer between transgenic cultivated beet and wild or volunteer populations.

One part of the project involved gathering basis data about wild and volunteer beet. This represents the current status quo, which can then be used as a basis for determining possible changes through outcrossing of transgenic sugar beet.

  • How widely dispersed is wild beet in Germany? Where does it come from?
  • Which plant populations are suitable for monitoring? With which methods?
  • How badly infested with fungi and nematodes is wild beet on natural sites?

The other part of the project investigated what effect the various transgenic traits (herbicide, virus, nematode and fungal resistance) might have on wild and volunteer forms.

  • Does the naturalisation and dispersal behaviour of the wild and volunteer beet change as a result of incrossing transgenes?
  • Is greater competitive strength found when the plants are infested with fungi, or does this affect the overwintering ability of the wild and volunteer beet?

Summary

Inventory of wild and volunteer beet: Following a comparison with data from earlier studies, the wild populations appear to be spreading in an east-west direction along the Baltic coast of Schleswig-Holstein.

Fungal and nematode infestation: It was observed that towards the end of the vegetation period (August) there was only limited fungal infestation in wild beet in its natural locations. Some populations were even free of symptoms.

It was not possible to study transgenic fungus-resistant plants because no such plants were available.

Experiment description

Competitive and overwintering ability

The plan was to carry out release experiments with transgenic fungus-resistant beet with and without fungal infestation. The competitive behaviour of transgenic wild/sugar beet hybrids and isogenic control plants was to be compared in the presence of a typical weed (Chenopodium album; a different number of plants per beet). The idea was to simulate a situation that could occur in the first year on a fallow field or on a natural site.

The idea was to study the survival probability of various transgenic sugar beet plants under typical sugar beet cultivation conditions. The plants were to be recorded after overwintering, along with the number, weight and germinability of the produced seed. The non-transgenic parent variety was used as a control.

Inventory of wild and volunteer beet

An inventory of the wild beet population was carried out on the German North Sea and Baltic coasts. Representative populations were selected for long-term monitoring. The wild beet were to be examined for nematode infestation. Wild beet populations in Italy and France – the place of origin of volunteer beet (seed production) – were also included.

The spread and origin of volunteer beet was investigated in the Rhineland, along the Baltic coast and in Breisgau. Diversity and relationship links were determined using molecular biological analyses and external features like leaf colour.

Various detection methods were developed for the monitoring programme:

  • PCR detection of the transgene (e.g. fungal resistance)
  • Detection of relationship links and the geographical origin of wild beet

Fungal and nematode infestation

The occurrence, spread and importance of fungal (Cercospora beticola) and nematode (Heterodera schachtii) infestation were investigated. Susceptibility to the fungus and nematodes was tested on at least five wild beet populations in the greenhouse. Sensitive cultivated varieties were used as a control.

Results

(see Summary)