Türkiye’de Antep fıstığı’nda alternaria yanıklık etmeni alternaria patojenlerinin fungisit direncinin incelenmesi

Alternaria blight is one of the important diseases of pistachio and wild relatives, and its management in pistachio orchards mainly relies on fungicide applications. But, it is observed the disease cannot be declined or controlled by fungicide treatment that might be due to development of fungicide resistance in Alternaria pathogens. On the other hand, wild Pistacia species and some pistachio trees which cultural practices are not applied are not exposed to fungicide treatments in nature. Isolates from orchards and wild systems may show difference in their sensitivities to fungicides. In this study, twenty-two isolates of Alternaria species from different hosts of Pistacia species were investigated in vitro for their sensitivity to different fungicides having different mode of action. Fungicide sensitivity were evaluated based on mycelial growth and spore germination of the isolates by using effective concentrations. The least effective fungicide was azoxystrobin and the most effective one was boscalid + pyraclostrobin among the fungicides tested in this study. Partial gene sequencing of succinate dehydrogenase genes presented boscalid sensitivity of the isolates according to the specific mutations related with boscalid resistance. This study is the first initiation to observe sensitivity of Alternaria pathogens from pistachio and wild relatives against to the most commonly used commercial fungicides in Turkey.Alternaria yanıklığı, Antepfıstığı ve yabani akrabalarını etkileyen önemli hastalıklardan biridir ve Antepfıstığı bahçelerinde hastalık kontrolü fungisit uygulamalarına dayalı olarak yürütülmektedir. Fakat, fungisit kullanımı ile hastalığın azalmadığı veya kontrol edilemediği görülmüştür ki bu durum Alternaria patojenlerinde fungisit direnci gelişmiş olmasından dolayı olabilir. Diger taraftan, yabani Pistacia türleri ve kültürel pratiklerin uygulanmadığı bazı Antepfıstığı ağaçları doğada fungisit uygulamalarına maruz kalmamaktadır. Kültür bahcelerindeki ve yabani ekosistemdeki izolatlar, fungisitlere karşı duyarlılıkta farklılık gösterebilir. Bu çalışmada, Pistacia türlerinin farklı konukçularından örneklenmiş yirmi iki izolatın, farklı etki mekanizmasına sahip fungisitlere karşı in vitro duyarlılıkları araştırılmıştır. Fungisit duyarlılıkları izolatların miselyal gelişim ve spor çimlenmesi üzerinden etkili konsantrasyon verileri ile değerlendirilmiştir. Test edilen fungisitler arasında izolatlar üzerinde etkisi en düşük olan fungisit azoxystrobin, en etkili olan ise boscalid+pyraclostrobin olarak bulunmuştur. Boscalid direnci ile ilişkilendirilen polimorfizmlere göre suksinat dehidrogenaz genlerinin kısmi baz dizilim verileri izolatların duyarlı olduğunu göstermistir. Bu çalışma, Türkiye’de, Antepfıstığı ve yabani akrabalarından örneklenmis Alternaria izolatlarının yaygın ticari kullanımı olan fungisitlere karşı duyarlılıklarını belirlemek üzere yapılan ilk başlangıç çalısmasıdır

Species diversity, mating type assays and aggressiveness patterns of Monilinia pathogens causing brown rot of peach fruit in Turkey

Brown rot disease caused by fungal species from theMonilinia genus has recently been observed as one of the most importantlimiting factors for yield and quality of peach fruits in Turkey. During Juneand July of 2018, field trips to different peach orchards were performed in sixprovinces located in four different geographical regions of Turkey. One hundredand twenty-nine isolates were obtained from the diseased fruits, and of those,109 were identified as Monilinia fructicola, whereas 20 were M. laxa accordingto the species-specific molecular markers. Mating types of the isolates weredetected by PCR assays using primers designed in this study. Each isolaterepresented only one of the mating type genes. Overall data sets presented 1:1ratio of mating types for both species, indicating a possible sexualreproduction. No polymorphisms were detected in partial sequences of matingtype genes. The isolates were in vitro tested for their pathogenicity using applefruits as a host and aggressiveness were evaluated at different time pointsusing lesion sizes. Monilinia laxa was found more aggressive than M.fructicola. Moreover, M. fructicola isolates displayed larger colony growthcompared to M. laxa isolates. However, no significant correlation was detectedbetween the colony growth rates and virulence. This study is the first to demonstratebrown rot pathogens of peach fruit in Turkey and identifies different aspectsof the pathogens, which would be useful in containment of pathogen spread andcomparison with other populations of these pathogens worldwide, and suggests anew set of mating type markers for these species.</p