FIRST REPORT OF VERTICILLIUM DAHLIAE CAUSING VERTICILLIUM WILT ON GOJI BERRY IN TURKEY
G. Özer, H. Bayraktar
Wilt symptoms of Goji berry plant (Lycium barbarum) were observed in nurseries in Bolu (Turkey) during a sanitary survey conducted in May 2015. One-year-old plants showed symptoms of wilting, stunting, yellowing, defoliation and vascular discoloration in the roots and stems. Small pieces of brownish vascular tissues were placed onto potato dextrose agar (PDA) after surface-disinfecting with 1% sodium hypochlorite. After 10 days of incubation at 25±1°C and 12 h photoperiod, many colonies developed with hyaline hyphae and irregular shaped black microsclerotia. The identification of fungal isolates was performed on the basis of morphological features such as elliptical single-celled conidia, verticillate conidiophores and microsclerotia (Hawksworth and Talboys, 1970). To confirm identity of the causal fungus, Verticillium dahliae, the internal transcribed spacer (ITS) region of rDNA was amplified for representative isolate using the primers ITS1/ITS4 (White et al., 1990) and sequenced (GenBank accession No. KX017569). BLASTn analysis of the 542 bp amplicon revealed 100% sequence identity with the sequence of a V. dahliae strain (AF104926). To fulfil Koch's postulates, 8-month-old Goji berry plants were inoculated by roots immersion into a conidial suspension (107 conidia/ml) for 30 min. Control plants were submerged in sterile tap water. All plants were transplanted into pots containing 1 l autoclaved soil and kept in a glasshouse. After 60 days, infected plants showed typical Verticillium wilt symptoms in the roots and stems, from which V. dahliae was consistently reisolated. To our knowledge, this is the first report of Goji berry Verticillium wilt disease in Turkey.