Diversity of microsatellites in natural populations of ascomycetous fungus, Emericella nidulans, in Israel on local and regional scales

The genetic divergence of Israeli populations of soil ascomycetous fungus Emericella nidulans was studied on regional and local scales using seven microsatellite (SSR) trinucleotide markers. The study was performed in the framework of the "Evolution Canyon" research program at the Institute of Evolution, University of Haifa, in three "Evolution Canyons" (EC): EC I (Mt. Carmel), EC II (western Upper Galilee), and EC III (the southern Negev desert). The first two canyons (EC I and EC II) are located in the northern part of Israel at a distance of 38 km. EC III is located to the south at a distance of nearly 350 km from the northern ECs. In each canyon, E. nidulans strains were isolated from the opposite slopes and (in EC III) the valley bottom. All three EC populations of E. nidulans were found to be genetically distinct. The estimated genetic divergences correspond to geographical distances and ecological differences among the three studied microsites. On a regional scale, SSR polymorphism tends to increase with severity of ecological conditions. In general, the effect of "structural" factors (predicted number of repeats in SSR markers and distance to the centromere) in the microsatellite diversity was higher compared to ecological factors.