Jumpponen, A. 1999. Spatial distribution of discrete phenotypes of Phialocephala fortinii
on a glacier forefront as inferred from RAPD markers. New Phytologist 141: 333-344.
Abstract
Phialocephala fortinii Wang & Wilcox is among the few identified hyphomycetes belonging to the
Mycelium radicis atrovirens complex. This ëdark-septate endophyteí has a global distribution and colonises 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 assayed by 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 ecto-, ericoid-, or non-mycorrhizal. The isolates showed substantial variation, sharing approximately half of the RAPD-markers on the average. 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 subsequent 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. These inhabited roots of several plants representing three different species. These data suggest that
the sharing of Phialocephala fortinii genets among plant species may play a
fundamental role in adaptation and interaction among the whole plant community in a system undergoing primary succession.
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