Genetic diversity in the fungus Fusarium solani f.sp. cucurbitae race 1, the casual agent of root and crown rot of cucurbits in Iran, using molecular markers.

Fusarium solani f.sp. cucurbitae race 1 is a pathogen on cucurbit plants. In this study genetic diversity among 26 isolates of Fusarium solani f.sp. cucurbitae race 1 was studied using Restriction Fragment Length Polymorphism (RFLP) of ITS (Interal Transcribed Spacer) regions and Random Amplified Polymorphic DNAs (RAPD) markers. Outcome of digestion with six restriction enzymes including EcoR I, Rsa I, Bme 181, Msp I, Hae III and Hind III, together with the patterns of restriction fragment length polymorphism of ITS regions divided the isolates into two groups. Deoxy Ribonuckin Acid DNA pattern was obtained for the isolates using 12 random primers and genetic distance between them was calculated and relationships (by cluster analysis) determined. Among the primers used, seven primers showed polymorphism. Genetic distance between isolate pairs ranged from 0.03 to 0.48. Genetic diversity was high (e.g., the isolates were distributed into 10 genetic groups at a similarity percentage of 75). The lowest distance was observed between isolates 50 and 73 and the highest distance observed between isolates 50 and 73 with isolate 102. Restriction fragment length polymorphism results show diversity in ITS regions, without any correlation to geographic origin and RAPD. However, this genomic regions usually have high constancy in species, but in this study diversity was shown in ITS regions even for race 1. The data suggest that taxonomical situation of Foc race 1 probably needs revision.