بررسي تنوع ژنتيكي جدايه هاي Sclerotinia sclerotiorum با استفاده از نشانگر rep-PCR

GENETIC DIVERSITY AND PATHOGENIC VARIABILITY OF Sclerotinia sclerotiorum ISOLATES USING rep-PCR MARKER

Sclerotinia stem rot caused by Sclerotinia sclerotiorum, is one of the most important disease of canola in Iran. Regarding to importance of this disease and the lack of comprehensive knowledge on genetic diversity of this pathogen in Iran, mycelia compatibility groupings (MCGs) and genetic variation among MCGs from Golestan, Mazandaran and western Azarbaijan provinces were examined. Sixty-four isolates were selected respecting to geographic distribution and their MCGs were determined. Among these tested isolates, 38 MCGs were identified. Pathogenecity tests were carried out in greenhouse and analysis of resulting data (lesion phenotype+lesion length+girdling) categorized isolates into three groups with different range of virulence. Our data indicated that virulence of isolates varied within one MCG and also between MCGs. Study of genetic diversity among MCGs (38 isolates representative of 38 MCGs), using banding pattern of four rep-PCR primers categorized isolates into seven groups at the 64% similarity level. Accordingly, majority of isolates were separated based on their geographic origin. The discriminatory power of rep- PCR genotyping (D = 0.993), which discriminated 37 different genotypes, was high, indicating that rep-PCR is a rapid, effective marker for genotyping S. sclerotiorum isolates.