We have screened the genome of ecto- and endo-mycorrhizal fungi
by using
primers designed on microsatellite sequences: (CT)8,
(CA)8, (GACA)4, (TGTC)4, (GTG)5.
PCR experiments proved that microsatellites such as (GTG)5 exist
as short
repeated sequences
in 11 species of Tuber (Ascomycetes) and seven species within
Glomales
(Zygomycetes). Variations in the banding pattern obtained
by DNA fingerprinting enabled all these species and some isolates to be
distinguished according to the number, size and intensity
of the fragments. (GACA)4 and (TGTC)4 also led to
successful amplifications in some isolates from Tuber and Glomales.
These
experiments demonstrate that microsatellite primers are reliable, sensitive
and technically simple tools for assaying genetic variability
in mycorrhizal fungi, and can be used to discriminate mycorrhizal symbionts
with different taxonomic features. (GTG)5 in fact led to
species-specific fingerprints in both truffles, which are closely related
species, and in Glomales, which are quite separate species in evolutionary
terms.