Akademik Veri Yönetim Sistemi
Plant Disease, cilt.100, sa.1, ss.219, 2016 (SCI-Expanded)
During 2011 to 2013, significant anthracnose symptoms were observed in spinach (Spinacia oleracea L.) at different times of the year in Hatay, Adana, and Mersin provinces in the Mediterranean Region of Turkey. A survey was performed in the affected regions, which included 11 fields in Hatay, 5 fields in Adana, and 12 fields in Mersin provinces (18 and 30 samples per location). Disease prevalence (percentage of fields showing foliar symptoms on plants) in these locations ranged between 40 and 75%. Symptoms included small, circular, water-soaked, tan-colored lesions (10 to 20 mm) on both young and old leaves. Older lesions became thin and papery, followed by larger chlorotic, blighted, and necrotic symptoms. Under wet or humid conditions, mature lesions produced dark acervuli with setae (50 to 100 μm long). Symptomatic tissues, taken from surface-sterilized infected leaves, were plated on spinach dextrose agar (SDA, juice of 250 g spinach, 20 g dextrose, 20 g agar in 1 liter distilled water) and incubated for 7 to 10 days at 25°C. The fungus produced a cottony white to pale-gray mycelium with hyaline, one-celled, falcate conidia (17 to 28 × 2.5 to 6 μm) borne on conidiophores in acervuli. Based on disease symptoms and morphological characters, the pathogen was identified as Colletotrichum spinaciae (Ellis & Halst) (Damm et al. 2009). For molecular identification, DNA was extracted from mycelium, actin and β-tubulin (TUB 2) genes were amplified with ACT512F-ACT793R and T1-Bt2b primers (Carbone and Kohn 1999; Glass and Donaldson 1995), and sequenced. The sequences were compared by BLAST search to the GenBank database and showed 99% similarity to C. spinaciae isolates (Accession Nos. GU227945 and GU228141). The DNA sequences were deposited into GenBank under Accession Nos. KP898448 and KR080474 for actin and beta-tubulin genes. To fulfill Koch’s postulates, pathogenicity tests were performed on leaves of fifteen 4- to 6- week-old spinach seedlings (cv. Matador) by spraying with conidial suspension (105 conidia per ml of sterile water) of each isolate of C. spinaciae. Control plants were treated with sterile distilled water only. All plants were covered with a clear polyethylene bags and incubated at 20°C for 48 h. The bags were removed, and plants were maintained in a dew chamber for 21 days at 60 to 70% relative humidity. Foliar symptoms identical to those observed in spinach fields were visible 14 to 21 days after inoculation. No lesions developed on the control plants. The experiments were repeated twice. The pathogen was readily reisolated on SDA from inoculated plants. The disease has been previously reported from Canada (Cerkauskas et al. 1991), North America (Correll et al. 1994), and Australia (Washington et al. 2006). To our knowledge, this is the first report of C. spinaciae on spinach in the Mediterranean Region of Turkey.