PHYLOGENETIC RELATIONSHIPS BETWEEN IRANIAN ISOLATES OF MICROSPHAERA AND ERYSIPHE S. LAT. BASED ON rDNA INTERNAL TRANSCRIBED SPACERS SEQUENCES

To study the phylogenetic relationships between Erysiphe s. lat. and Microsphaera, the nucleotide sequences of internal transcribed spacers ofrDNA including 5.8S rDNA gene were determined for 23 taxa. The results showed that Erysiphe. section Erysiphe and Microsphaera are closely related and clustered together with strong bootstrap support (100%). All oftaxa belonging to this group produce conidia singly. Whereas, these genera are distinguished by the morphology of appendages which is dichotomously branched in Microsphaera and mycelioid in Erysiphe. Erysiphe. sect. Golovinomyces and Erysiphe. sect. Galeopsidis, both of which are well characterized by conidia produced in chains, formed two different groups. The percentages of sequence divergence ranged from 2 to 7.8% between Microsphaera and Erysiphe. sect. Erysiphe.