In the 2016-17 growing seasons, surveys were conducted in the Isparta, Uşak, Kütahya and Denizli provinces of Turkey to identify the Rhizoctonia solani AG-4 associated with root and crown rot of chickpea. A total of 75 isolates of Rhizoctonia were obtained from surveyed areas. Visual diagnostic, isolation and microscopic observation identified the causal organism as R. solani. Sequence data of the ITS rDNA region confirmed the species identity and revealed that the anastomosis group of the 23 isolates were AG-4 HGII. The isolates were variable in their morphological characters. The sequences generated during this study were clustered in the same branch with the reference isolates of R. solani AG-4 HGII based on their ITS sequencing on chickpea and the isolate grouping was not related to their geographic origins or virulence pattern. Pathogenicity tests revealed that all AG-4 isolates were pathogenic on chickpea and the disease severity values of 23 isolates varied between 42.8% and 100%. Based on the virulence, the isolates were grouped into two categories: 5 of them exhibited moderately virulence and 18 of them exhibited highly virulence reaction on chickpea. The high virulent isolate level (>50% disease severity) was determined as 78.2% of all 23 isolates. This is the first report of R. solani AG-4 as a pathogen of chickpea in Turkey.
A survey was conducted in Ankara and Eskisehir provinces of Turkey for determining anastomosis groups and pathogenicity of Rhizoctonia species associated with root and crown rot of wheat. Pathogenicity tests revealed that Rhizoctonia solani AG 8 caused the common symptoms of damping-off and stunting.
In July 2009, a leaf blotch disease was observed on sorghum in Sakarya Province, Turkey. Disease incidence and severity were rated at 45% and 25 to 75%, respectively. Typical symptoms included elliptical, straw-colored, necrotic lesions with darker margins. The lesions eventually coalesced, resulting in drying of leaves. A fungus was isolated from the lesions on potato dextrose agar (PDA) incubated under near ultraviolet light for 12 h daily at 22°C for 2 weeks. Flexuous conidiophores of the fungus were solitary or produced in small groups. They were geniculate with numerous well-defined scars, medium to dark brown, ≥300 μm long, and 4 to 9 μm thick. Five to eight or more conidia were produced on the apices of the conidiophores. The conidia were straight, oblong or cylindrical, rounded at the ends, golden brown at maturity except for a small area just above the dark scar, pseudoseptate, and 20 to 31 × 7.5 to 12.5 μm (1). The causal fungus was identified as Bipolaris spicifera (Bain) Subram. (teleomorph Cochliobolus spicifer Nelson). The identification was confirmed with specific PCR primers (Bipol-1 F: 5′-CAGTTGCAATCAGCGTCAGT-3′, R: 5′-AAGACAAAAACGCCCAACAC-3′, Bipol-2 F: 5′-GTGTTGGGCGTTTTTGTCTT-3′, R: 5′-CCTACCTGATCCGAGGTCAA-3′, Bipol-3 F: 5′-GATGAAGAACGCAGCGAAAT-3′, R: 5′-AAGACAAAAACGCCCAACAC-3′). These primers were designed by the authors using Primer3 primer design software and sequences of B. spicifera found in GenBank. PCR products were amplified from nuclear DNA of the cultured fungus and were sequenced after cleaning with a Beckman 8000 CEQ DNA sequencer. Sequences amplified using Bipol-1 and Bipol-2 showed 99 to 100% similarity with B. spicifera sequences from GenBank. The DNA sequence amplified using Bipol-2 was deposited in GenBank (Accession No. HQ538774). B. spicifera has been reported previously as pathogenic in Africa, North and South America, Asia, Australia, Oceania, and the West Indies on Agrostis, Avena, Cymbopogon, Cynodon, Dactylis, Desmostachya, Eleusine, Holcus, Hordeum, Oryza, Panicum, Pennisetum, Phleum, Poa, Saccharum, Sorghum, Triticum, and Zea spp. (3). Pathogenicity tests were conducted on sorghum (Sorghum bicolor (L.) Moench) and Sorghum × sudangrass hybrid cultivars. From PDA cultures, conidia were collected in sterile distilled water with a concentration of 3% Tween 20. Twenty-five plants (five per pot) were inoculated by spraying the conidia (105 ml–1) onto 21-day-old plants, which were then maintained at 25 ± 2°C in a greenhouse following 48 h in a humid chamber. The test was repeated once. Control plants were sprayed with sterile distilled water. Typical symptoms (2) were obtained from all inoculated plants 7 days after inoculation. No symptoms developed on the control plants. The pathogen was reisolated from inoculated leaves to fulfill Koch's postulates. To our knowledge, this is the first report of B. spicifera on sorghum in Turkey. References: (1) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, Surrey, England, 1971. (2) H. Koo et al. Plant Pathol. J. 19:133, 2003. (3) A. Sivanesan. Mycologia Papers 158:1, 1987.
Sclerotium rolfsii Sacc. (the sclerotial state of Athelia rolfsii (Cruzi) Tu and Kimbrough), the soil-borne pathogen on several plants all over the world, has been previously reported from Turkey on certain plants. In this study, turfgrass areas in 9 provinces of Turkey were firstly surveyed for S. rolfsii, and samples showing chlorotic, reddish-brown, and frog-eye shaped circular patches were collected. Totally, 32 Sclerotium rolfsii isolates were obtained from these areas. One mycelial compatibility group (MCG) was identified among S. rolfsii isolates. Disease severity in pathogenicity tests carried out in the greenhouse ranged from 83.74 to 92.87%. Identification of fungal and bacterial isolates used in the study was performed by DNA sequencing analysis. Five antagonistic bacterial strains, previously found as effective on controlling some fungal pathogens, were tested to determine their antifungal effects against the southern blight by using seed coating method in greenhouse conditions. In consequence of the biological control studies, Bacillus cereus 44bac and Stenotrophomonas rhizophila 88bfp were found more effective than the other strains with the ratio of 91.00 and 90.11%, respectively.
Embellisia spp., Curvularia inaequalis and Phaeosphaeria pontiformis were found. Among the all of the isolates, M. nivale and F. oxysporum on wheat and F. oxysporum on barley were determined to be the most common root pathogen. Pathogenicity tests were conducted using hypocotyl test and plant test. As a result of tests, W. circinata var.
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