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An ATP-binding Cassette Multidrug-Resistance Transporter Is Necessary for Tolerance of Gibberella pulicaris to Phytoalexins and Virulence on Potato Tubers

February 2002 , Volume 15 , Number  2
Pages  102 - 108

André Fleiβner , Claudia Sopalla , and Klaus-Michael Weltring

Institut für Botanik, Westfälische Wilhelms-Universität, Schlossgarten 3, 48149 Muenster, Germany

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Accepted 23 October 2001.

The necrotrophic pathogen Gibberella pulicaris infects potato tubers through wounds that contain fungitoxic secondary metabolites such as the phytoalexins rishitin and lubimin. In order to colonize tuber tissue, the fungus must possess a mechanism to tolerate potato defense compounds. In this paper, we show that a gene, Gpabc1, that codes an ATP-binding cassette (ABC) transporter is required for tolerance to these phytoalexins and for virulence on potato. The Gpabc1 gene, isolated in the course of a differential cDNA screen, shares high sequence homology with the ABC1 gene of Magnaporthe grisea. G. pulicaris mutants deficient in Gpabc1 were still able to metabolize rishitin but lost their tolerance to this phytoalexin as well as their virulence on potato. These results strongly suggest that the Gpabc1-encoded ABC transporter is necessary for tolerance of G. pulicaris to rishitin and that this tolerance is required for virulence on potato.

© 2002 The American Phytopathological Society