Identification and Pathogenicity of Pythium Species Isolated from the Wheat Fields of Eskişehir Province

Öz

Wheat (Triticum spp.) is a staple food for approximately 35% of the world’s population and is cultivated in 102 countries, covering 32% of global arable land. Disease agents are among the factors that decrease wheat yield and quality. Embryo and root infections caused especially by soil-borne pathogens reduce yield by negatively affecting plant growth and tillering. Pythium species are polyphagous pathogens that cause root rot and damping-off diseases on various plants. They are also responsible for diseases known as brown root rot and snow rot, causing serious yield losses on wheat plants. In this study, morphological and molecular characterizations of Pythium isolates obtained from plant and soil samples collected from wheat fields in Eskişehir province were conducted and their pathogenicity on susceptible melon seedlings and wheat plants was investigated. Selective VP3 medium was used for the isolations. A total of 224 isolates belonging to this genus were obtained, comprising 5 from diseased wheat roots and 219 from soil samples. All the isolates were grouped into three categories according to their morphological features, and molecular identification revealed that they belonged to the species P. heterothallicum, P. oligandrum, P. paroecandrum, P. rhizosaccharum, P. sp. hordeum, and P. ultimum var. ultimum. Among these, P. rhizosaccharum and P. sp. hordeum species were reported for the first time in Türkiye by this study. In the pathogenicity experiments, it was determined that the virulence levels of different species and some isolates in the same species were different from each other. While P. heterothallicum and P. ultimum isolates significantly reduced germination rates of wheat seeds and caused severe damping-off disease in the pathogenicity trial, virulence of P. oligandrum and P. paroecandrum isolates was found lower. These findings indicate that some Pythium species have a high potential to cause disease on wheat plants, whereas species with lower virulence may serve as promising agents for biological control.

Anahtar Kelimeler

• Triticum spp.
• Pythium spp.
• Soil-borne pathogen
• Brown root rot
• Snow rot
• Virulence

Destekleyen Kurum

Scientific Research Projects Coordination Unit of the Isparta University of Applied Sciences

Proje Numarası

Project no: 2023-D1-0227

Etik Beyan

There is no need to obtain permission from the ethics committee for this study.

Teşekkür

This study is a part of the PhD thesis of the first author, accepted by the Institute of Graduate Education, Isparta University of Applied Sciences (Isparta, Türkiye), and supported by the Scientific Research Projects Coordination Unit of the same University (Project no: 2023-D1-0227), Türkiye. The authors are grateful to the Plant Health Clinic Application and research Center of Hatay Mustafa Kemal University for their help in the molecular identification of the isolates.

Eskişehir İli Buğday Alanlarından İzole Edilen Pythium Türleri ve Patojeniteleri

Öz

Buğday (Triticum spp.), dünya nüfusunun yaklaşık %35’i için temel besin maddesi olup, 102 ülkede ve ekili alanların %32’sinde yetiştirilmektedir. Hastalık etmenleri buğday verimini ve kalitesini düşüren faktörler arasındadır. Özellikle toprak kökenli patojenlerin neden olduğu embriyo ve kök enfeksiyonları bitki gelişimini ve kardeşlenmeyi olumsuz etkileyerek verim düşüklüğüne yol açmaktadır. Pythium türleri çok sayıda bitkide kök çürüklüğü ve çökerten hastalıklarına neden olan polifag patojenlerdir. Buğdayda da kahverengi kök çürüklüğü, kar çürüklüğü gibi isimlerle bilinen ve ciddi kayıplara neden olan hastalıklardan sorumludurlar. Bu çalışmada, Eskişehir ilindeki buğday alanlarından alınan bitki ve toprak örneklerinden elde edilen Pythium izolatlarının morfolojik ve moleküler karakterizasyonları yapılarak duyarlı kavun fideleri ve buğday bitkileri üzerindeki patojeniteleri incelenmiştir. İzolasyonlarda seçici VP3 ortamı kullanılmıştır. Bu cinse ait toplam 224 izolat elde edilmiş olup, bunların 5’i hastalık belirtisi gösteren buğday köklerinden, 219’u ise toprak örneklerinden elde edilmiştir. Tüm izolatlar morfolojik özelliklerine göre üç gruba ayrılmış; moleküler tanılama sonucunda ise P. heterothallicum, P. oligandrum, P. paroecandrum, P. rhizosaccharum, P. sp. hordeum ve P. ultimum var. ultimum türlerine ait oldukları belirlenmiştir. Bunlardan P. rhizosaccharum ve P. sp. hordeum türleri ülkemizde ilk kez bu çalışma ile bildirilmektedir. Patojenite denemelerinde türlerin ve aynı türe ait bazı izolatların virulensleri arasında farklılıklar olduğu belirlenmiştir. P. heterothallicum ve P. ultimum izolatları genelde buğday tohumlarının çimlenme oranını düşürerek şiddetli çökerten hastalığına neden olurken, P. oligandrum ve P. paroecandrum izolatlarının virulensleri daha düşük bulunmuştur. Sonuçlar, bazı Pythium türlerinin buğdayda hastalık oluşturma potansiyelinin yüksek olduğunu gösterirken, virulensi daha düşük olan ve önceki çalışmalara dayanılarak mikoparazit oldukları bilinen türlerin ise biyolojik mücadelede kullanılabilirlik açısından önemli olabileceğini ortaya koymaktadır.

Anahtar Kelimeler

• Triticum spp.
• Pythium spp.
• Toprak kökenli patojen
• Kahverengi kök çürüklüğü
• Kar çürüklüğü
• Virulens

Destekleyen Kurum

Scientific Research Projects Coordination Unit of the Isparta University of Applied Sciences

Proje Numarası

Project no: 2023-D1-0227

Etik Beyan

There is no need to obtain permission from the ethics committee for this study.

Teşekkür

This study is a part of the PhD thesis of the first author, accepted by the Institute of Graduate Education, Isparta University of Applied Sciences (Isparta, Türkiye), and supported by the Scientific Research Projects Coordination Unit of the same University (Project no: 2023-D1-0227), Türkiye. The authors are grateful to the Plant Health Clinic Application and research Center of Hatay Mustafa Kemal University for their help in the molecular identification of the isolates.

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