Determination of Genetic Diversity Within Ascochyta rabiei (Pass.) Labr., the Cause of Ascochyta Blight of Chickpea in Turkey

Genetic diversity among 64 isolates of Ascochyta rabiei
obtained from diseased chickpea plants in 18 different
provinces of Turkey was characterized by microsatellite-
primed PCR using di-, tri- and tetra-nucleotide repeats. Of sixteen primers tested, ten amplified 61 bands, of which 56 were polymorphic. UPGMA (Unweighted Pair Group Method with Arithmetic Average) analysis, performed with the resulting data of SSR (Simple Sequence Repeats) fingerprints clustered Turkish isolates of A. rabiei into seven groups. However, these groups did not correspond to their geographic
origin. Group 2, the largest group consisting of 35 isolates
from 16 different provinces, clustered together with one Syrian isolate belonging to pathotype 3 while isolates belonging to pathotypes 1 and 2 did not cluster with any isolate originating from Turkey. The highest genetic diversity within geographical populations was found in the South Eastern Anatolia region (Shannon index: 0.156). Also, rDNA ITS (Internal transcribed spacer) regions of isolates representative of each group were sequenced. The ITS1-5.8S-ITS2 sequences were highly conserved among all groups of A. rabiei. This is the first report on detection of genetic diversity in A. rabiei populations in Turkey. The SSR fingerprints (three or four repeats) generated using A. rabiei DNA indicated that such microsatellites are useful for population studies in this fungus.