Climatic effects on microsatellite diversity in wild emmer wheat (Triticum dicoccoides) at the Yehudiyya microsite, Israel

Microsatellite (SSR) diversity at 28 loci comprising seven types of tandem dinucleotide repeated motifs was analyzed in 105 individual plants of wild emmer wheat, Triticum dicoccoides, from a microsite in Yehudiyya, northeast of the Sea of Galilee, Israel. The study area was less than 1000 m(2) and involved 12 paired plots distributed in a mosaic pattern. Each experiment involved very close (a few meters apart), but sharply divergent, microclimatic niches in the open park forest of Tabor oak: (1) sun, between trees, and (2) shade, under tree canopy. Significant microclimatic divergence characterized many loci displaying asymmetric and non-random distribution of repeat numbers. Niche-specific and niche-unique alleles and linkage disequilibria were found in the two sub-populations. Microsatellite diversity at both single- and two-locus levels is affected by microclimatic environment. The evidence reflects effects of ecological stresses and natural selection on SSR diversity, resulting presumably in adaptive structures.