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Genetische lnstabilität des Rishitin Metabolismus some Toleranz und Vinilenz eines Stammes von Gibberella pulicaris auf Kartoffelknollen
Author(s) -
Weltring K.M.,
Loser K.,
Weimer J.
Publication year - 1998
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/j.1439-0434.1998.tb04770.x
Subject(s) - virulence , biology , phytoalexin , strain (injury) , phenotype , microbiology and biotechnology , spore , genetics , gene , biochemistry , anatomy , resveratrol
Two strains of the potato pathogen Gibberella pulicaris were analysed for the ability to metabolize the phytoalexin rishitin and for virulence on potato tubers. While strain R‐6380 was always virulent and able to metabolize the phytoalexin, strain R‐7843 showed significant variation in both traits. Analysis of eight sectors of a radially grown culture of this strain revealed that six had a virulent, rishitin‐metabolizing phenotype, one had an avirulent, rishitin‐nonmetabolizing phenotype, and one had an intermediate phenotype for both traits. Similar results were found for single spores isolated from one of two spore suspensions from different agar cultures. In all cases high virulence was associated with fast metabolism of rishitin; weakly virulent strains only slowly degraded the phytoalexin. Restriction‐fragment‐length‐polymorphism (RFLP) analysis of sectors with contrasting phenotypes and measurement of the nuclear DNA content from these sectors indicate that the sectors were identical to the original strain (R‐7843) with respect to these traits. It is therefore concluded that the variations observed in virulence and in the ability to metabolize rishitin are the result of spontaneous genetic changes in strain R‐7843, The concurrent changes in tolerance, metabolism and virulence are further indicators of a relationship among these traits and lend support to the hypothesis that phytoalexin metabolism is important in pathogenicity.