Genetic variability of Ascochyta rabiei: Population structure revealed by RAPD analysis and classification into pathotypes

The poor definition of variation in the ascochyta blight fungus has historically hindered strategies for reducing blight disease damage to the chickpea crop in the West Asia and North Africa. We applied RAPD and microsatellite markers to construct genotype-specific, DNA fragment profiles of Syrian field isolates of this fungus. By using conventional pathogenicity tests and genome analysis with DNA markers, we show that the DNA markers distinguished the major pathotypes in Syria, and defined the organization of clonal lineages within and among pathotype groups. Further, we demonstrate that these markers could be used for pathogenicity surveys to identify the most predominant genotype in the population. On the basis of the surveys, a general picture of A. rabiei evolution in Syria and its implications in the plant disease management are discussed.