Early events of vesicular–arbuscular mycorrhiza formation on Ri T-DNA transformed roots

Authors

  • G. BÉCARD,

    1. Centre de Recherche en Biologie Forestière, Faculté de Foresterie et de Géodésie, Université Laval, Ste-Foy, Québec, GIK 7P4, Canada
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  • J. A. FORTIN

    1. Centre de Recherche en Biologie Forestière, Faculté de Foresterie et de Géodésie, Université Laval, Ste-Foy, Québec, GIK 7P4, Canada
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  • The authors wish to thank Dr Suha Jabaji-Hare, Dr Keith Egger and Dr Sally Smith for reviewing and correcting the manuscript. This research was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC grant A-3235 to J. André Fortin).

SUMMARY

An in vitro system using Ri T-DXA transformed roots and the vesicular–arbuscular mycorrhizal fungus Gigaspora margarita Becker & Hall has been developed to study the initial events of mycorrhiza formation. Sucrose, sodium and phosphorus were found to be critical components of the medium used to establish the dual culture. Using a single spore as inoculum it was consistently possible to obtain colonization of a preselected point on the root and to time the colonization process (within 5 days). Abundant viable and aseptic spores can be obtained. The system is especially appropriate for studying the triggering of the fungal biotrophy towards the root.

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