Population analysis of Didymella rabiei (Anamorph: Ascochyta rabiei) causing ascochyta blight in wild and domesticated Cicer spp. in view of genetic, ecologic and pathogenic features

Genetic structure, in vitro temperature growth response and aggressiveness traits of Turkish and Israeli Didymella rabiei isolates from wild and domesticated chickpea were studied. The six STMS loci were used to determine genetic variation of 128 D. rabiei isolates. Turkish isolates exhibited the highest genetic diversity (H=0.69) within the investigated D. rabiei populations. EF1-? sequences distinguished between D. rabiei isolates from domesticated and wild Cicer spp. by four nucleotid polymorphisms. While D. rabiei populations from domesticated and wild hosts genetically far away from each other, a few isolates from the different origins were genetically close to each other as demonstrated using the Bayesian algorithm as well as with the PCoA. Gene/genotype flows were estimated by using population genetic differentiation values among the populations from different origins. Isolates from domesticated chickpea had larger colony areas at 25 °C than at 15 °C while the isolates from wild hosts had the vice versa and these in vitro phenotypic observations were supported by the heritability values of the temperature growth response. Except for Turkish isolates from domesticated chickpea, isolates from different origins had higher aggressiveness on their original hosts indicating the host adaptation. All the data concluded that the distinct ecological selections of wild and domesticated chickpea systems result in ecological divergence of D. rabiei populations.