Molecular Identification of Physiological Races of Fusarium oxysporum f. sp . lycopersici and radicis lycopersici Causal Agent of Fusarium Wilt of Tomato in Iran

Abstract

Recently, vascular wilt disease has caused considerable damages in tomato greenhouses. Fusarium oxysporum is a common pathogen of tomato and produces a variety of toxins, pigments, and phytohormones. It has caused huge crop damage in south of Iran. Damage increases in relatively warm climate. Fusarium oxysporum were identified from contaminated tissues. Thirty five of 50 isolates from samples collected from tomato greenhouses in southeast of Iran were identified as F. oxysporom . Then, F. oxysporum f. sp. lycopersici (Fol) and F. o xysporum f. sp. radicis lycopersici (Forl) were differentiated from each other by host range and molecular methods. Fol is only pathogenic on tomato and Forl is pathogenic on other hosts from Cucurbitaceae family in addition to tomato. Molecular identifica tion of isolates was obtained by Hirano methods. DNAs of each isolates were reproduced by using uni, sp13 and sp23 specific primers. Based on this study, 4 isolates were identified as race1, 4 isolates as race 2, 13 isolates as race 3, and 14 isolates as F orl . This is the first report of formae speciali s and physiological races of this pathogen in this region. Race 3 is reported for the first time in Iran. Keywords : Formae speciales, PCR, Physiological races, Specific primer.