VIEW ARTICLE

Physiology and Biochemistry

Phytoalexins from Potatoes: Evidence for the Conversion of Lubimin to 15-Dihydrolubimin by Fungi. E. W. B. Ward, Agriculture Canada, Research Institute, University Sub Post Office, London, Ontario, Canada N6A 5B7; A. Stoessl, Agriculture Canada, Research Institute, University Sub Post Office, London, Ontario, Canada N6A 5B7. Phytopathology 67:468-471. Accepted for publication 18 October 1976. Copyright © 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-468.

Lubimin, added to cultures of Phytophthora capsici, Glomerella cingulata, or Fusarium sulphureum was converted to a compound identified as 15-dihydrolubimin. Monilinia fructicola and P. infestans did not perform the conversion. In potato tubers inoculated with these fungi 15-dihydrolubimin accumulated as a major product with the first three fungi and not with the last two. The conversion did not appear to be a detoxification mechanism or related to pathogenicity. The significance of the findings is discussed in relation to phytoalexin production in potatoes, particularly with regard to possible fungal or bacterial modification of precursors produced by the plant.