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  • Küçük Resim Yok
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    Analysis of molecular resistance mechanisms in helicoverpa armigera (hübner) (noctuidae: lepidoptera) populations under pyrethroid stress in turkey
    (2014) Konus, Metin; Uğurlu Karaağaç, Sakine; Iscan, Mesude
    Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is a major pest of economically important crops such as cotton, tomato and soybean. In order to control this pest, pyrethroid insecticides have been extensively used in farming areas all over the world. However, applications of excessive amounts of these insecticides can result in resistance development in the field populations of H. armigera. Resistance to the pyrethroids, beta-cypermethrin and lambda cyhalothrin, was analysed using bioassays. It was found that a Çanakkale field population of H. armigera field showed low (2.1-fold) and moderate (14.5-fold) resistance levels for beta-cypermethrin and lambda-cyhalothrin, respectively. Furthermore, expressions of selected CYP450, GST and esterase genes of H. armigera Çanakkale field populations were compared to those of a susceptible strain using real-time PCR. Our results indicate that H. armigera reacts to pyrethroids mainly by increasing expression levels of CYP450s such as CYP9A12 and CYP9A14. However, GST and esterase genes expression levels were not significantly altered in a field population. GSTs and esterases were also analyzed using biochemical assays. While GSTs and esterase genes were not found to be up-regulated in the real-time PCR, except GST-DCNB activity, the biochemical assays also showed no significant increases in enzyme activities in the Çanakkale field population as compared to the susceptible strain. Consequently, CYP9A12 and CYP9A14 together with certain GSTs, catalyzing DCNB substrate, are proposed to be involved in the metabolic responses against beta-cypermethrin and lambda-cyhalothrin insecticides in field population of H. armigera from Turkey.
  • Küçük Resim Yok
    Öğe
    Analysis of Molecular Resistance Mechanisms in Helicoverpa armigera (Hubner) (Noctuidae: Lepidoptera) Populations Under Pyrethroid Stress in Turkey
    (Gazi Entomological Research Soc, 2014) Konus, Metin; Karaagac, Sakine Ugurlu; Iscan, Mesude
    Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) is a major pest of economically important crops such as cotton, tomato and soybean. In order to control this pest, pyrethroid insecticides have been extensively used in farming areas all over the world. However, applications of excessive amounts of these insecticides can result in resistance development in the field populations of H. armigera. Resistance to the pyrethroids, beta-cypermethrin and lambda cyhalothrin, was analysed using bioassays. It was found that a canakkale field population of H. armigera field showed low (2.1-fold) and moderate (14.5-fold) resistance levels for beta-cypermethrin and lambda-cyhalothrin, respectively. Furthermore, expressions of selected CYP450, GST and esterase genes of H. armigera canakkale field populations were compared to those of a susceptible strain using real-time PCR. Our results indicate that H. armigera reacts to pyrethroids mainly by increasing expression levels of CYP450s such as CYP9Al2 and CYP9A14. However, GST and esterase genes expression levels were not significantly altered in a field population. GSTs and esterases were also analyzed using biochemical assays. While GSTs and esterase genes were not found to be up-regulated in the real-time PCR, except GST-DCNB activity, the biochemical assays also showed no significant increases in enzyme activities in the canakkale field population as compared to the susceptible strain. Consequently, CYP9Al2 and CYP9A14 together with certain GSTs, catalyzing DCNB substrate, are proposed to be involved in the metabolic responses against beta-cypermethrin and lambda-cyhalothrin insecticides in field population of H. armigera from Turkey.
  • Küçük Resim Yok
    Öğe
    Real-time PCR analysis of pyrethroid resistance in Helicoverpa armigera from Turkey
    (Turkish Biochem Soc, 2014) Konus, Metin; Karaagac, Sakine Ugurlu; Iscan, Mesude
    Aim: Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) is a polyphagous pest of a wide range of crops such as cotton, tomato and soybean. Pyrethroid insecticides have commonly used against it in agricultural areas, but excess amount applications of them result in resistance development in the field populations of H. armigera. Resistance development usually occurs with increased metabolism of certain enzymatic systems such as CYP450, GST and esterases. Therefore, expressions of selected CYP450, GST and esterase genes of H. armigera field populations (Adana and Mardin) were compared to those of a susceptible strain by real-time PCR method for analyzing role of these systems in pyrethroid resistance development of H. armigera. Material and Methods: Real-Time PCR Method Results: It was found that H. armigera reacts to pyrethroids mainly by increasing expressions of CYP9A14 gene together with CYP4S1 and CYP9A12 genes. However, analyzed GST and esterase genes expression were not significantly changed in field populations. Conclusion: Consequently, while CYP450 enzyme system is actively involved in pyrethroid resistance, GSTs and esterases enzyme systems don't seem to be actively involved in resistance development against pyrethroid insecticides in H. armigera field populations from Turkey.
  • Küçük Resim Yok
    Öğe
    Türkiye’deki helicoverpa armigera’da piretroid dayanıklılığının gerçek zamanlı pcr ile analizi
    (2014) Konus, Metın; Uğurlu Karaağaç, Sakine; Iscan, Mesude
    Amaç: Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) polifag bir zararlı olup pamuk, domates ve soyafasuyesi gibi geniş bir ürün grubunun zararlısıdır. Tarımsal alanlarda bu zararlıya karşı yaygın olarak piretroid insektisitler kullanılmaktadır fakat bu insektisitlerin aşırı miktarda kullanımı H. armigera'nın tarla populasyonlarında direnç oluşumuna neden olmaktadır. Dayanıklılık oluşumu genellikle CYP450, GST ve esteraz gibi enzim sistemlerinin metabolik hızının artmasıyla olmaktadır. Bu nedenle, Adana ve Mardin tarla populasyonlarındaki CYP450, GST ve esteraz enzim sistemlerinden seçilen genlerin ekspresyonu hassas populasyonla gerçek zamanlı PCR yöntemiyle karşılaştırılarak bu sistemlerin piretroid dayanıklılıktaki rolleri analiz edildi.Gereç ve Yöntemler: Gerçek zamanlı PCR yöntemiBulgular: H. armigera'nın tarla populasyonun'nun piretroidleri başta CYP9A14 olmak üzere CYP9A12 ve CYP4S1 ile birlikte metabolize ettiği bulundu. Bununla birlikte, analiz edilen GST ve esteraz genleri tarla populasyonlarında anlamlı bir değişiklik göstermedi.Sonuç: Sonuç olarak, CYP450 enzim sistemi piretroid dayanıklılığına aktif olarak katılırken, GST ve esteraz enzim sistemlerinin H. armigera'nın tarla populasyonlarında dayanıklılık oluşumuna aktif olarak katılmadıkları saptandı