Molecular karyotypes for Alternaria plant pathogens known to produce host-specific toxins

Hajime Akamatsu, Masatoki Taga, Motoichiro Kodama, Richard Johnson, Hiroshi Otani, Keisuke Kohmoto

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    98 Citations (Scopus)


    There are at least ten plant diseases caused by Alternaria species in which host-specific toxins (HSTs) are responsible for fungal pathogenicity. Of these HST-producers, seven are considered distinct pathotypes of the species Alternaria alternata, and the remaining three are among other species of pathogenic Alternaria. Inter- and intra-specific variation among Alternaria taxa, including HST-producers, was determined by electrophoretic karyotyping using pulsed-field gel electrophoresis. A. alternata including seven pathotypes of A. alternata and eight non-pathogenic strains had 9-11 chromosomal bands with estimated sizes ranging from 0.4 to 5.7 Mb. In contrast, Alternaria species that are morphologically distinct from A. alternata had 8-10 bands with sizes between 0.9 and 5.7 Mb. Estimated genome sizes of A. alternata and other Alternaria species ranged from 28.8 to 33.6 Mb and 25.1 to 30.7 Mb, respectively. Other species of pathogenic Alternaria were difficult to differentiate from A. alternata on the basis of chromosome-size polymorphisms alone, but Southern analysis using rDNA as a probe could, in some cases, differentiate between them. These results were cytologically confirmed by 4',6-diamidino-2-phenylindole (DAPI) staining and fluorescence in situ hybridization with a rDNA probe for mitotic metaphase chromosomes prepared by the germ-tube burst method.

    Original languageEnglish
    Pages (from-to)647-656
    Number of pages10
    JournalCurrent Genetics
    Issue number6
    Publication statusPublished - 1999


    • Alternaria alternata
    • Electrophoretic karyotype
    • Fluorescence in situ hybridization
    • Host-specific toxin

    ASJC Scopus subject areas

    • Genetics


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