Browsing by Author "Alkan, Mehtap"

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Bipolaris sorokiniana associated with common root rot in Azerbaijan and Kazakhstan
(2022) Alkan, Mehtap; Bozoğlu, Tuğba; Derviş, Sibel; Paulitz,Timothy C.; Özdemir, Fatih; Morgounov, Alexey; Mumınjanov,Hafiz; Amer, Mohammed; Imren, Mustafa; Dababat, Abdelfattah A.; Özer, Göksel
Wheat (Triticum spp.) is the third most important crop in terms of global production, with an average annual production of almost 219 million ha and yielding 760.9 million tons, after maize and rice. However, A complex of fungi attacking the crown and root tissues of wheat causes a serious problem and significant yield reductions in wheat. Although most prevailing species in this complex can change yearly and regionally in dryland winter wheat production areas, Bipolaris sorokiniana Shoemaker (teleomorph: Cochliobolus sativus) is one of the dominant species and causes spot blotch and common root rot (CRR) on wheat plants, especially in winter wheat varieties. Comprehensive surveys were conducted to identify B. sorokiniana associated with CRR of wheat throughout the main wheat-growing areas of Azerbaijan and Kazakhstan in 2017 and 2019, respectively. As a result of the classification of species based on morphological and molecular tools, 96 and 547 isolates were identified as B. sorokiniana for Azerbaijan and Kazakhstan, respectively. All surveyed regions for these countries were contaminated with this pathogen. Some representative isolates of B. sorokiniana were tested for their ability to cause disease and produced moderate disease severities on cultivar Seri 82 (Triticum aestivum, bread wheat). The percent incidence of B. sorokiniana isolates in all isolates was 15.2% for Azerbaijan, whereas, for Kazakhstan, B. sorokiniana was the most frequently recovered species in the three regions surveyed, with an isolated frequency of 44.80%. The results of the current study provide crucial and helpful information to improve disease management strategies against CRR of wheat in these countries.
Correction to: Leaf spot caused by Alternaria crassa on Datura stramonium in Turkey
(Australasian Plant Disease Notes, 2022) Bozoğlu, Tuğba; Alkan, Mehtap; Derviş, Sibel; Özer, Göksel
In August 2021, jimson weed (Datura stramonium) plants growing as weeds in potato fields in Bolu province, Turkey, exhibited leaf spots with dark concentric rings. Sunken and lens-shaped lesions with a light center were also frequently observed on petioles, branches, and stems. Based on morphological characteristics and phylogenetic analysis of the transcription elongation factor 1-α, RNA polymerase second largest subunit, and glyceraldehyde-3- phosphate dehydrogenase loci, the causal agent was identified as Alternaria crassa. The pathogen was successfully re-isolated from inoculated jimson weed plants in the pathogenicity assay, proving Koch’s postulates. Alternaria crassa caused necrotic lesions on potato plants, similar to those of early blight, confirming them as an alternative host of the pathogen. This is apparently the first report of leaf spot caused by A. crassa on jimson weed in Turkey.
First report of leaf blight of Turkish oregano (Origanum onites) caused by Neoscytalidium dimidiatum in Turkey
(SpringerLink, 2021) Alkan, Mehtap; Özer, Göksel; Koşar, İslim; Güney, İnci Güler; Derviş, Sibel
In July 2020, a leaf blight disease with intense defoliation on Turkish oregano (Origanum onites L.) plants was observed in a pilot experiment feld in Akçakale and a commercial feld in Haliliye with an incidence of 5.4 and 11.7%, respectively, in Şanlıurfa province. After a surface-sterilization for 1 min with 1% NaOCl, isolations from symptomatic tissues of six afected plants for each feld consistently yielded a fungus with the same colony morphology on potato dextrose agar. Cultures were powdery with a thick aerial mycelium, initially white that changed from olive green to black within 10 days.
First report of needle blight of blue spruce (Picea pungens) caused by Neoscytalidium dimidiatum in Turkey
(SpringerLink, 2023) Derviş, Sibel; Türkölmez, Şahimerdan; Güney, İnci Güler; Alkan, Mehtap; Özer, Göksel
The blue spruce (Picea pungens Engelm.) is an exotic conifer species widely used for decorative purposes in landscaping and private gardens. In 2020, 60% of forty blue spruce trees between 20 and 25 years old planted in front of buildings in Kavaklıdere, Ankara, displayed needle blight symptoms. Needles on the lower and interior crown closest to the trunk were infected from the bottoms of branches. They showed a brown-colored or burned appearance before dropping off, starting from their tips, resulting in up to a 65% reduction of the canopy. On the surface of infected tissues, a black-colored fungal mass was observed. Fungal colonies isolated from twenty symptomatic branches and needles were initially dark gray and became black within 4 to 7 days. Zero- to one-septate dark brown conidia (4.6 to 9.8 × 3.6 to 7.5 μm) formed in arthric chains were disarticulating and cylindrical-truncate to rod-shaped, oblong, ellipsoidal, doliiform, or globose, consistent with the description of Neoscytalidium spp. (Crous et al. 2006). The internal transcribed spacer, translation elongation factor 1-α, and β-tubulin loci of a randomly selected isolate (Nd_Pp01) were sequenced using the primers ITS1/4, EF1-728 F/986R, and Bt2a/Bt2b and deposited in GenBank under the accession numbers OK643641, OK666381, and OK666382, respectively. The sequences had 99.77–100% nucleotide identity with those of the type specimen of N. dimidiatum, CBS 145.78. Phylogenetic analysis with concatenated sequences further confirmed the identification. The isolate was deposited in the Bolu Abant Izzet Baysal University Culture Collection with accession number BAIBU-179. A pathogenicity test was conducted with ten 1-year-old P. pungens plants by spraying a conidial suspension (105 conidia/ml) of the isolate Nd_Pp01 onto the needles (Türkölmez et al. 2019). Five seedlings sprayed with sterile water were used as controls. All plants were placed in a growth chamber at 28°C with 70% RH. Spray-inoculated needles initially showed yellow spots within two weeks and turned brown six weeks after inoculation, whereas the controls remained symptom-free. The pathogen was re-isolated from the inoculated needles but not from controls. To our knowledge, this is the first report of N. dimidiatum causing needle blight on P. pungens in Turkey and worldwide (Farr and Rossman 2023).
Leaf spot caused by Alternaria crassa on Datura stramonium in Turkey
(SpringerLink, 2022) Bozoğlu, Tuba; Alkan, Mehtap; Derviş, Sibel; Özer, Göksel
In August 2021, jimson weed (Datura stramonium) plants growing as weeds in potato felds in Bolu province, Turkey, exhibited leaf spots with dark concentric rings. Sunken and lens-shaped lesions with a light center were also frequently observed on petioles, branches, and stems. Based on morphological characteristics and phylogenetic analysis of the transcription elongation factor 1-α, RNA polymerase second largest subunit, and glyceraldehyde-3- phosphate dehydrogenase loci, the causal agent was identifed as Alternaria crassa. The pathogen was successfully re-isolated from inoculated jimson weed plants in the pathogenicity assay, proving Koch’s postulates. Alternaria crassa caused necrotic lesions on potato plants, similar to those of early blight, confrming them as an alternative host of the pathogen. This is apparently the frst report of leaf spot caused by A. crassa on jimson weed in Turkey
Molecular phylogeny of plant pathogenic fungi based on start codon targeted (SCoT) polymorphism
(Springer, 2023) Palacıoğlu, Gülsüm; Alkan, Mehtap; Derviş, Sibel; Bayraktar, Harun; Özer, Göksel
Background: A number of molecular marker systems have been developed to assess genetic diversity, carry out phylogenetic analysis, and diagnose and discriminate plant pathogenic fungi. The start codon targeted (SCoT) markers system is a novel approach used here to investigate intra and interspecific polymorphisms of phytopathogenic fungi. Materials and methods: This study assessed genetic variability between and within 96 isolates of ten fungal species associated with a variety of plant species using 36 SCoT primers. Results: The six primers generated 331 distinct and reproducible banding patterns, of which 322 were polymorphic (97.28%), resulting in 53.67 polymorphic bands per primer. All primers produced informative amplification profiles that distinguished all fungal species. With a resolving power of 10.65, SCoT primer 12 showed the highest polymorphism among species, followed by primer 33 and primer 29. Polymorphic loci (PPL), Nei's diversity index (h), and Shannon index (I) percentages were 6.25, 0.018, and 0.028, respectively. UPGMA analysis separated all isolates based on morphological classification and revealed significant genetic variation among fungal isolates at the intraspecific level. PCoA analysis strongly supported fungal species discrimination and genetic variation. The other parameters of evaluation proved that SCoT markers are at least as effective as other DNA markers. Conclusions: SCoT markers were effective in identifying plant pathogenic fungi and were a powerful tool for estimating genetic variation and population structure of different fungi species.
Selenyumun Bazı Bitki Patojeni Funguslara Karşı In Vitro Değerlendirmesi
(2024) Özer, Göksel; Türkkan, Muharrem; Sönmez, Ferit; Kabakcı, Hüseyin; Alkan, Mehtap; Derviş, Sibel; Derviş, Sibel
Amaç: Selenyum (Se), tarımsal alanlarda fungal patojenlerini kontrol etmek için umut vaat eden çevre dostu bir element olarak ilgi çekmektedir. Bu çalışmada, sodyum selenit (selenit) ve sodyum selenat (selenat) formlarını içeren Se uygulamalarının 10 farklı bitki patojeni fungus türünün büyümesi üzerindeki etkisi değerlendirilmiştir. Materyal ve Yöntem: Selenyum uygulamalarının fungusların miselyal gelişmesi ve spor oluşumu üzerindeki etkisi in vitro koşullarda değerlendirilmiştir. Probit analizi, fungusların hem miselyal gelişme hem de spor oluşumunda %50 azalmaya (EC50) yol açan tuz konsantrasyonlarını belirlemek için kullanılmıştır. Araştırma Bulguları: En yüksek konsantrasyonda (120 ppm), selenit tüm türlerin miselyal gelişmesini %6.82 ile %62.46 arasında engellemiştir. Buna karşın, selenat daha geniş bir engelleme spektrumu göstermiş ve miselyum büyümesini %0 ile %87.14 arasında etkilemiştir. Farklı konsantrasyonlarda, Fusarium pseudograminearum selenit karşısında (EC50<24 ppm) en yüksek duyarlılığı gösterirken onu Bipolaris sorokiniana ve Verticillium dahliae izlemiştir. Benzer şekilde, Colletotrichum coccodes selenat uygulamasına karşı (EC50<24 ppm) en yüksek duyarlılığı gösterirken, onu B. sorokiniana, Botrytis cinerea, Sclerotinia sclerotiorum ve V. dahliae takip etmiştir. Her iki tuz da anlamlı bir farklılık gözlenmeksizin fungal türleri üzerinde spor oluşumunu etkili bir şekilde inhibe etmiştir. Colletotrichum coccodes, F. pseudograminearum, B. cinerea, F. culmorum, V. dahliae ve B. sorokiniana selenit tarafından anlamlı şekilde inhibe edilmiştir fakat F. oxysporum’a karşı daha düşük bir inhibisyon gözlenmiştir. Benzer şekilde, engelleme yüzdeleri arasında küçük farklar bulunmakla birlikte bu türler, V. dahliae ve F. oxysporum ile birlikte, selenat tarafından anlamlı şekilde inhibe edilmiştir. Colletotrichum coccodes, B. cinerea, F. culmorum, B. sorokiniana ve F. oxysporum için 24 ppm'nin altındaki EC50 değerleri, her iki tuzun da spor oluşumunu etkin bir şekilde inhibe ettiğini göstermiştir. Fusarium pseudograminearum’un %50 inhibisyonu için daha yüksek konsantrasyonların gerektiği anlaşılmıştır. Verticillium dahliae, selenit karşısında 33.16 ppm ve selenat karşısında 24 ppm'nin altında olan EC50 değerleri ile selenata karşı daha yüksek duyarlılık göstermiştir. Sonuç: Bu çalışmanın bulguları, Se'nin sürdürülebilir tarımda çeşitli bitki patojen fungus türleri üzerindeki antifungal potansiyeline ilişkin anlayışımıza katkıda bulunmaktadır. Hastalık yönetimi için elementin mekanizmalarını anlamak ve uygulama protokollerini optimize etmek için daha fazla araştırmaya ihtiyaç vardır.