Molecular identification of 85 fungal isolates from Romanian wheat cultivars collected between 2007 and 2008 was performed by PCR assays using specific primer pairs for F. graminearum, F. culmorum and F. sporotrichoides. Chemotype determination was achieved with primers for four genes involved in trichothecene biosynthesis (tri3, tri7, tril2 and tril3). The pathogenity of 19 Fusarium isolates against two wheat cultivars was tested and deoxynivalenol content was achieved by HPLC-RP assays. PCR analysis revealed that F. graminearum was the most prevalent species, representing 83.5%. The amplicon produced by primer set tox5-1/tox5-2 was present in 88.23% of the tested Fusarium isolates, indicating their thricothecene biosynthesis potential. Molecular analysis proved no nivalenol producers in the tested isolates, shown that all F. culmorum isolates were 3- acetyldeoxynivalenol chemotype and all F. graminearum isolates were 15- acetyldeoxynivalenol chemotype. Pathogenity test resulted in germination inhibition, reduction of seedling length and necrosis. Infected seeds showed deoxynivalenol level almost three times higher for F. culmorum isolates than for F. graminearum isolates. This is the first report of molecular identification of Fusarium isolates and corresponding trichothecene chemotypes in Romanian pathogen population, proving the highest prevalence of F. graminearum, but also the presence of F. culmorum with higher aggressiveness on tested wheat cultivars.
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