Page 45 - E-Tez Bülteni Mart 2026, Sayı 5

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MASTER’S THESIS
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Department of Molecular Biotechnology
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Biologıcal Control Of Cotton Pest Helicoverpa Armigera
B i o l o g ı c a l C o n t r o l O f C o t t o n P e s t H e l i c o v e r p a A r m i g e r a
Using Rna Interference (Rnai) Technology
U s i n g R n a I n t e r f e r e n c e ( R n a i ) T e c h n o l o g y
H a l i m e K A R A T E K E
Halime KARATEKE
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T Thesis Supervisor: Prof. Dr. Remziye NALÇACIOĞLU
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Thesis Summary
Helicoverpa armigera (Hübner, 1808) is a member of the lepidopteran order of the Noctuidae family. It is an effective polyphagous
species that causes serious damage to agricultural crops in many parts of the world. Control is generally achieved with synthetic
insecticides. The development of resistance in insects to synthetic insecticides, coupled with the harm they cause to humans and other
non-target organisms, has necessitated the development and use of alternative biological control preparations. RNA interference
(RNAi) is an alternative method for controlling pest populations. This method provides a species-specific control method by silencing
vital genes in target insects. Chitin, an important biological polymer, is found in all arthropods, including insects. Furthermore, chitin and
the enzymes involved in its synthesis are not found in plants or humans. This study aimed to silence the expression of the Chitin
synthase B (CHSB) gene, which is involved in chitin synthesis, using double stranded RNA (dsRNA) technology. For this purpose, the
CHSB gene from H. armigera larvae was amplified by polymerase chain reaction and subsequently cloned into a dsRNA synthesis
vector (L4440). dsRNA synthesis was performed in a bacterial system (E. coli HT115 (DE3) strain). Subsequently, both the dsRNA-
expressing bacterial suspension and the total RNA purified from these cells were mixed with separate feed and fed to H. armigera
larvae. The effects of dsRNA on insects were investigated through bioassay experiments. Both dsRNAexpressing E. coli cells and
RNA’s isolated from these cells induced significant mortality in thirdinstar H. armigera larvae, reaching 40% and 35%, respectively,
whereas control treatments exhibited negligible effects.
Keywords: dsRNA, Chitin Synthase B, RNA interference, Helicoverpa armigera