Περίληψη:
Verticillium wilt of oilseed rape is caused by the host-adapted pathogen
Verticillium longisporum comb. nov. With one set of nuclear SSU-rRNA
gene primers, a PCR amplification product of ca. 2.5 kb was generated
from all isolates of V. longisporum tested (36 from Europe, Japan, and
USA), with the exception of two recombinant isolates. On the contrary,
all the other phytopathogenic and non-phytopathogenic species of
Verticillium tested (18 species, 46 isolates), with the exception of one
isolate of V. lecanii and two of Cordyceps sp., generated a product of
cn. 1.65 kb. Sequence analysis of the SSU-rRNA gene of two typical
isolates of V. longisporum (wild radish, Japan, and oilseed rape,
Germany) revealed that this dimorphism was due to the presence of an
identical 839-bp intron located in a highly conserved insertion position
(nt 1165 of Saccharomyces cerevisiae). The intron sequence was
classified as group-I intron on the basis of conserved sequence and
secondary structural elements. Primers designed from the 839-bp intron
sequence amplified only the V. longisporum. Phylogenetic analysis based
on SSU-rDNA sequences showed that V. longisporum was closely related to
the genera of other filamentous Ascomycetes with fruiting bodies.
