Newly characterized pathogenicity-correlated genes are suitable in a PCR-test for a further differentiation of <em>Fusarium oxysporum</em> f. sp. <em>lycopersici</em>-isolates from the JKI strain collection

Abstract

Fusarium oxysporum forma specialis (f. sp.) lycopersici was evaluated as an example from the JKI strain col­lection to detect the occurrence of the pathogenicity-correlated conditional dispensable (CD) chromosome via PCR. Only in Fusarium oxysporum f. sp. lycopersici the CD-chromosome could be detected, while it was not detected in the closely related F. sp. radicis-lycopersici.

The theory of a transfer of the CD-chromosome into different clonal lines of F. oxysporum was tested by the application of partly-specific primers to investigate the chromosomal background of each isolate. Ten conserved Fusarium oxysporum f. sp. lycopersici isolates of the JKI strain collection were clearly differentiated into two chromosomal categories, when three partly-specific primer pairs were applied. With these experiments it could be shown that Fusarium oxysporum f. sp. lycopersici was polyphyletic, i. e. there are two different Fusarium oxysporum f. sp. lycopersici lines in the JKI strain collection possessing the CD chromosome. In future, polyphyletic studies could be used as an additional criterion for the classification of Fusarium isolates.