Phialocephala fortinii is among the few identified hyphomycetes
belonging to the Mycelium radicis atrovirens
complex. This ‘dark-septate endophyte’ has a global distribution
and colonizes a wide variety of host plants.
In this study, the spatial distribution of discrete genets of P. fortinii
on the forefront of a receding glacier
was analysed using the randomly amplified polymorphic DNA (RAPD) technique
to determine plants colonized
and patterns of colonization. In two consecutive years of sampling, a total
of 74 isolates of P. fortinii were obtained
from nine plant species, typically ectomycorrhizal, ericoid mycorrhizal
or non-mycorrhizal. The isolates showed
substantial variation, sharing on average approx. half the RAPD markers.
In the first year, three isolates belonging
to a single genet were obtained from two plants separated by a distance
of nearly 1.5 m. The continuity of this genet
was assessed by a sampling the following year. No isolates similar to that,
or any of the genets collected the year
before were observed. Consequently, the identical isolates from the previous
year were concluded to represent
discontinuous ramets. Two additional large genets were observed during
the second year of sampling, which
inhabited roots of several plants representing three different species.
These data suggest that the sharing of P.
fortinii genets among plant species might play a fundamental role
in adaptation and interaction within the whole
plant community in a system undergoing primary succession.