Akamatsu H, Taga M, Kodama M, Johnson R, Otani H, Kohmoto K
United Graduate School of Agricultural Sciences, Tottori University, Tottori 680-8553, Japan.
Curr Genet. 1999 Jul;35(6):647-56. doi: 10.1007/s002940050464.
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.
至少有十种由链格孢属物种引起的植物病害，其中寄主专化毒素（HSTs）是真菌致病性的原因。在这些产生HST的物种中，七种被认为是链格孢的不同致病型，其余三种属于其他致病链格孢物种。使用脉冲场凝胶电泳通过电泳核型分析确定了包括产生HST的链格孢分类群之间的种间和种内变异。包括七种链格孢致病型和八种非致病菌株的链格孢有9 - 11条染色体带，估计大小在0.4至5.7 Mb之间。相比之下，在形态上与链格孢不同的链格孢属物种有8 - 10条带，大小在0.9至5.7 Mb之间。链格孢和其他链格孢属物种的估计基因组大小分别为28.8至33.6 Mb和25.1至30.7 Mb。仅根据染色体大小多态性，其他致病链格孢物种很难与链格孢区分开来，但使用rDNA作为探针的Southern分析在某些情况下可以区分它们。这些结果通过4',6-二脒基-2-苯基吲哚（DAPI）染色以及用rDNA探针进行荧光原位杂交在细胞学上得到了证实，该探针用于通过芽管破裂法制备的有丝分裂中期染色体。
