Study of Polygalacturonase Activity and Genetic Diversity of Forty-two Iranian Isolates of Ascochyta rabiei

Ascochyta rabiei is one of the devastaining fungi pathogens of chick-pea (Cicer arietinum L.) crops. In the present investigation, forty-two Iranian isolates of Ascochyta rabiei fungi (including highly, weakly and moderate virulent isolates), whose pathogenisities were determined previously, were studied. Polygalacturonase is a main factor in the initiation of Ascochyta blight disease. Therefore fungi were cultured in Pectic Zymogram/PZ (with pH 4.5) medium for six days. PG presence in culture media confirmed by test plate. Polygalactoronase/PG activity assayed by Collmer methods. Clustring of isolates based on PG activity were performed by UPGMA (Unweighted pair grouped method by arithmatic average) method. Results indicated that PG activity differentiated HV from WV isolates from any province. Another study, DNA were extracted from mycelium by Dellaporta method, RAPD (Random Amplified Polymorphic DNA) reactions were performed by twelve arbitrary 9-10-mer primers. DNA polymorphism was studied in PCR products of the isolates using UPGMA method. Results showed that, the DNA amplification by RAPD (Ar171 and Ar082 primers) obtained high polymorphic pattern. On the other hand, genetic variability between isolates of A. rabiei was detectable but polymorphic pattern of these primers did not differentiate HV from WV isolates.