Characteristics of Polish Isolates of Fusarium sambucinum: Molecular Identification, Pathogenicity, Diversity and Reaction to Control Agents

Pathogenicity of 28 Polish isolates of F. sambucinum to potato tubers, their sensitivity to control agents, diversity among isolates and molecular methods of species identification were examined. All isolates were pathogenic to potato tubers and differences in pathogenicity were found. Isolates on the PDA were classified into three different color groups of mycelium (B - bright-beige, P - salmon pink, R - rose) that varied in pathogenicity and mycelium growth rate on PDA. P colonies showed the greatest tuber damage, but they grew the slowest on the PDA. Isolates showed varied reaction to different concentrations of 4 control agents (M - mancozeb, C- captan, CO - copper oxychloride and GE - grapefruit extract). The highest mycelium growth inhibition (MGI) was caused by M and the lowest by CO. Strong MGI by GE was observed especially for P isolates. Individual isolates showed different susceptibility to the control agents. Identification of isolates was determined in PCR assay with species specific FSF1/FSR1 primers, by sequencing of DNA fragments derived from ITS regions and the translation elongation factor-1 alpha gene (TEF). Sequence of the ITS regions were identical for all isolates. Analysis of the TEF DNA fragments showed one SNP (transition C↔T) in the sequences of isolates from the three different color groups.