Browsing by Author "Turkkan, Muharrem"

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Citation - WoS: 1
Citation - Scopus: 0
Armillaria Species Causing Kiwifruit Vine Decline and Root Rot in Northeastern Türkiye: a Growing Concern for Kiwifruit Health
(Wiley, 2024) Derviş, Sibel; Bozoglu, Tugba; Dervis, Sibel; Erper, Ismail; Ozer, Goksel; Department of Organic Agriculture / Organik Tarım Bölümü
Kiwifruit (Actinidia deliciosa) production in northeastern T & uuml;rkiye is facing an emerging threat from Armillaria root rot. Surveys conducted in August 2021 and 2022 revealed that 10.5%-17.5% of the 200-500 vines within each of 35 kiwifruit orchards in the Per & scedil;embe, G & uuml;lyal & imath; and Alt & imath;nordu districts of Ordu province exhibited symptoms of Armillaria root rot, including complete defoliation. Diseased plants exhibited diagnostic signs on their root collars and woody roots, including white mycelial fans, extensive wood rot and rhizomorphs. A single Armillaria isolate was obtained from each of the 35 symptomatic orchards. Molecular identification, employing DNA sequencing of the large subunit (LSU) region of rDNA, the translation elongation factor subunit 1-alpha (TEF1) gene and the second largest RNA polymerase II B-subunit (RPB2) gene, identified 20 isolates as Armillaria gallica and 15 as A. mellea. Phylogenetic analyses, based on TEF1 alignments, further supported the species identification with a 100% bootstrap value. To examine genetic diversity, start codon targeted (SCoT) marker 13 was used, successfully differentiating the two Armillaria species and revealing three distinct clades. Clades I and II comprised 15 and 5 isolates of A. gallica, respectively, while Clade III contained all 15 A. mellea isolates. Pathogenicity testing on kiwifruit seedlings (cv. Hayward) revealed the ability of both A. gallica and A. mellea isolates to induce disease. Rhizomorph-producing isolates in kiwifruit seedlings displayed high virulence, inducing severe leaf necrosis and seedling mortality, while isolates lacking these structures were non-pathogenic. This study identifies the first global instance of A. gallica causing kiwifruit root rot. This finding, along with the identification of A. mellea as a causal agent in the country, highlights the emerging threat of Armillaria root rot to kiwifruit production in the region.
Citation - WoS: 0
Armillaria Species Causing Kiwifruit Vine Decline and Root Rot in Northeastern Turkiye: a Growing Concern for Kiwifruit Health (Vol 172, E13409, 2024)
(Wiley, 2025) Derviş, Sibel; Bozoglu, Tugba; Dervis, Sibel; Erper, Ismail; Ozer, Goksel; Department of Organic Agriculture / Organik Tarım Bölümü
Citation - WoS: 0
Citation - Scopus: 0
First Report Of Colletotrichum Perseae Causing Anthracnose Disease of Avocado ( Persea Americana) in Türkiye
(Academic Press Ltd- Elsevier Science Ltd, 2024) Derviş, Sibel; Turkkan, Muharrem; Ozer, Goksel; Guney, Inci Guler; Dervis, Sibel; Department of Organic Agriculture / Organik Tarım Bölümü
Colletotrichum-induced anthracnose is a major disease of avocado (Persea americana), causing significant losses in production worldwide. In 2023, a survey of avocado fruits in markets within the K & imath;z & imath;ltepe district of Mardin, T & uuml;rkiye, revealed symptoms of anthracnose, characterized by brown-black lesions and internal necrosis. To identify the causal agent, 20 symptomatic avocado fruits were collected and fungal isolates resembling Colletotrichum species were obtained. Morphological characterization, multilocus sequence analysis of the internal transcribed spacer (ITS), actin (act), the apn2-Mat1-2 intergenic spacer (ApMat), and calmodulin (cal) loci, and pathogenicity testing were performed for only two representative isolates (Pa01 and Pa02). These analyses identified the pathogen as Colletotrichum perseae. The isolates readily formed ascomata on all culture media tested, suggesting a high capacity for sexual reproduction. Pathogenicity tests confirmed that C. perseae caused characteristic dark, sunken anthracnose lesions on avocado fruits. This is the first report of C. perseae causing anthracnose in avocados in T & uuml;rkiye, expanding the known geographical distribution of this pathogen. The findings highlight the need for effective disease management strategies and further research to understand the pathogen's lifecycle, environmental conditions favoring infection, and potential for seedborne transmission.
Citation - WoS: 1
Citation - Scopus: 1
Ganoderma Butt Rot of Hazelnut (corylus Avellana) Caused by ganoderma Adspersum in Türkiye
(Wiley, 2024) Derviş, Sibel; Dervis, Sibel; Ozgumus, Oezlem; Ozer, Goeksel; Department of Organic Agriculture / Organik Tarım Bölümü
In September 2022, hazelnut trees in six orchards in the & Ccedil;ar & scedil;amba district of Samsun province, a major hazelnut production area in the Black Sea region of T & uuml;rkiye, showed symptoms of leaf yellowing, shoot dieback, decline, basal stem rot and the presence of brown bracket-like sessile basidiocarps. Approximately 5%-10% of hazelnut trees were affected, highlighting the significant impact of the disease. A comprehensive morphological analysis was conducted to characterize fungal isolates obtained from symptomatic tissues as G. adspersum. This analysis incorporated features observed in basidiomata from declining trees and those reproduced after isolates were cultivated on wheat grain for spawn production and grown on an oak sawdust-based substrate. Confirmation of identification was achieved through the utilization of the internal transcribed spacer (ITS), large subunit (LSU) and small subunit (SSU) loci, along with sequencing and subsequent phylogenetic analysis. The G. adspersum isolates generally exhibited no significant growth differences at similar temperatures but demonstrated enhanced growth at 30 degrees C, while growth was completely inhibited at 40 degrees C. Incompatible reactions between isolates confirmed that distinct genotypes were present, highlighting genetic diversity within the species. In the pathogenicity trials, employing a single infested wheat grain per inoculation at the wounded site, hazelnut suckers exhibited distinct brown discolouration surrounding the inoculation site following a 2.5-month incubation period. Significantly, lesions exceeding 3 cm in length were observed, providing clear evidence of vigorous pathogenic activity by G. adspersum. This study is the first report of G. adspersum causing butt rot in hazelnuts, underscoring the significance of this finding for hazelnut cultivation and providing a foundation for future research and disease management strategies.
Molecular and Pathogenic Characterization of Fusarium Species Associated With Dry Rot in Stored Potatoes in Kyrgyzstan
(Springer, 2025) Derviş, Sibel; Dervis, Sibel; Ozer, Goksel; Turkkan, Muharrem; Bozoglu, Tugba; Alkan, Mehtap; Erper, Ismail; Department of Organic Agriculture / Organik Tarım Bölümü
Fusarium dry rot is a significant fungal disease impacting postharvest potato tubers worldwide, leading to substantial losses in tuber quality, nutritional value, and seed viability. In Kyrgyzstan, where potato is a staple crop, the disease poses a critical threat to food security. This study aimed to identify and characterize Fusarium species associated with dry rot in stored potatoes from the Osh region, a major potato production area facing severe postharvest challenges. Surveys were conducted in 34 potato storage facilities across four districts, and symptomatic tubers were collected. Fifty-four Fusarium isolates were obtained and subjected to a comprehensive characterization approach, including morphological assessments, molecular analyses using iPBS markers based on retrotransposons, DNA sequencing of the translation elongation factor-1 alpha (TEF1) locus, and pathogenicity tests on the 'Soraya' potato cultivar. Fusarium sambucinum was the most prevalent species (50%), followed by F. oxysporum (similar to 17%), F. flocciferum (similar to 11%), F. equiseti (similar to 9%), F. proliferatum (similar to 5%), F. acuminatum (similar to 4%), F. solani (similar to 2%), and F. venenatum (similar to 2%). Morphological identifications were supported by iPBS2395 primer analysis, which revealed distinct DNA fingerprinting patterns among the isolates. Phylogenetic analysis of TEF1 gene sequences further confirmed species identifications, demonstrating strong congruence between morphological, iPBS, and TEF1 data. Pathogenicity tests revealed varying levels of virulence across species, with F. sambucinum exhibiting the highest overall virulence and mean lesion sizes comparable to those of F. flocciferum, while F. equiseti and F. solani showed significantly lower virulence. Except for F. sambucinum, all other Fusarium species represent first reports in Kyrgyzstan, with F. flocciferum being reported globally for the first time as a causal agent of potato dry rot. This study provides a comprehensive assessment of the Fusarium species involved in dry rot in the Osh region, highlighting the dominance of F. sambucinum and the need for enhanced management strategies to mitigate postharvest losses and strengthen food security in Kyrgyzstan.
Citation - WoS: 1
Citation - Scopus: 1
Morphological, physiological, molecular, and pathogenic insights into the characterization of Phytophthora polonica from a novel host, hazelnut (Corylus avellana)
(Academic Press Ltd- Elsevier Science Ltd, 2024) Derviş, Sibel; Ozer, Goksel; Dervis, Sibel; Department of Organic Agriculture / Organik Tarım Bölümü
Hazelnuts, constituting a significant global crop, hold paramount importance in Turkiye, contributing to approximately 71.14 % of the world's hazelnut cultivation area. In the summer of 2023, hazelnut trees in two orchards situated in the Altinordu district of Ordu province, within the Black Sea region of Turkiye, the largest producer and exporter of hazelnuts, exhibited symptoms of decline associated with root rot. Phytophthora sp. was consistently isolated from necrotic taproots, initiating an in-depth study to discern the causal agent behind the observed hazelnut decline. The species was identified as P. polonica by its distinctive morphological traits, including homothallic characteristics, amphigynous or paragynous antheridia, long nonbranching sporangiophores, and nonpapillate sporangia with internal proliferation. Multiple genetic markers (ITS, tub2, and COI) facilitated a clear differentiation of P. polonica from other Phytophthora species within Clade 9, supporting its classification within Subclade 9b. This investigation also evaluated the impact of diverse nutrient media (CA, V8A, and CMA), temperatures, and pH levels on the mycelial growth of P. polonica HPp-1 and HPp-2 isolates. The optimal conditions for maximal mycelial growth were determined through the D-optimal design of the Response Surface Method, revealing the significant influence of all factors on mycelial growth. The identified optimal conditions were at 26.09 degrees C, pH 5.12, with CMA as the nutrient medium. Validation experiments conducted under these optimal conditions unveiled mycelial growth of 7.24 +/- 0.15 mm day(-1) and 6.81 +/- 0.09 mm day(-1) for P. polonica HPp-1 and HPp-2 isolates, respectively, with an error of less than 5 %. Pathogenicity assessments confirmed P. polonica's virulence on hazelnuts, with distinct lesion development observed in twig inoculation, cut stem segments, and foliar tests. While no statistically significant difference was noted in lesion areas between HPp-1 and HPp-2 isolates in twig and stem segment assays, a statistical difference in leaf lesion areas (19.96 +/- 2.04 cm(2) and 9.16 +/- 3.43 cm(2)) emerged in foliar tests after only a 5-day incubation period, indicating their high susceptibility to the pathogen. This study is the first to report P. polonica as a hazelnut pathogen in Turkiye and around the world, highlighting the previously non-existent threat of Phytophthora root rot in hazelnuts, given the substantial lack of scientifically documented cases related to hazelnut root rot diseases. The quadratic model design employed in physiological analyses is reliable for optimizing mycelial growth and can serve as a guiding framework for similar investigations.
Neoscytalidium Dimidiatum as a Postharvest Pathogen Affecting Solanaceous Vegetables
(Wiley, 2025) Derviş, Sibel; Ozer, Goksel; Turkolmez, Sahimerdan; Turkkan, Muharrem; Dervis, Sibel; Department of Organic Agriculture / Organik Tarım Bölümü
Neoscytalidium dimidiatum, a member of the Botryosphaeriaceae family, is an emerging global plant pathogen. Although recently reported on various hosts in T & uuml;rkiye, its impact on commercially available vegetables remained undocumented. This study provides the first report of N. dimidiatum causing postharvest decay in the eggplant (Solanum melongena L.), pepper (Capsicum annuum), potato (Solanum tuberosum), and tomato (Solanum lycopersicum) obtained from local Turkish markets in 2023. The pathogen was identified through morphological characterisation and molecular analysis targeting the internal transcribed spacer (ITS) region, translation elongation factor 1-alpha (tef1), and beta-tubulin (tub2) gene sequences. The pathogenicity of N. dimidiatum was confirmed through Koch's postulates at 28 degrees C, and its temperature-dependent effects were assessed on solanaceous vegetables. Disease progression, measured by the area under the disease progress curve (AUDPC), was strongly influenced by temperature. No disease was observed at 12 degrees C. At 18 degrees C, limited disease development occurred in the eggplant and potato. AUDPC values increased significantly at 25 degrees C, generally peaking at 30 degrees C, with some hosts showing similar levels of disease severity at 35 degrees C. These findings highlight the critical role of postharvest temperature control, particularly rapid cooling and cold storage, in minimising losses caused by N. dimidiatum. This is the first report of N. dimidiatum as a postharvest pathogen affecting the eggplant, pepper, tomato fruits, and potato tubers, and the first record of this pathogen on the eggplant and pepper globally, expanding its known host range and reinforcing its significance as an emerging threat to global agriculture.