에센셜오일에 대한 미각습관화에 의해 유도된 담배거세미나방(Spodoptera litura)의 섭식저해 감소 및 신경 둔감화

학위논문(석사) -- 서울대학교대학원 : 농업생명과학대학 농생명공학부, 2024. 2. 탁준형.The tobacco cutworm, Spodoptera litura, is one of the most important agricultural insect pests. Plant essential oils can be considered potential candidates for eco-friendly control agents, as they exhibit not only insecticidal but also feeding deterrent activity. In the present study, antifeedant and insecticidal activity of 29 essential oils were investigated. Additionally, their potential for habituation and association with the gustatory sensilla were examined. In no-choice tests and contact-fumigation bioassays on third instar larvae, clove bud, fennel sweet, and lemongrass oils exhibited notable activities, but no direct correlation between insecticidal activity and feeding deterrence was observed. The second instar larvae were pre-exposed to those active oils. Larvae reared with lemongrass and clove bud oils showed gustatory habituation, whereas those with fennel sweet oil did not show any desensitization compared to the control. Comparable outcomes were observed in individuals exposed to the main constituents of the three oils. Additionally, a synergistic feeding deterrent effect was observed in the mixture of fennel sweet and clove bud oils. However, although statistically not significant, potential habituation for the mixture was observed, and only robust inhibition of habituation were expected at physiologically high concentration (FDI90+FDI90). Electrophysiological studies showed that the response of the maxillary palp to citral decreased in the experienced group, while trans-anethole was maintained at levels similar to the naive group. The reduction in feeding deterrence corresponded to the repeated exposure and desensitization of the maxillary palp, varying with the types of essential oils.담배거세미나방(Spodoptera litura)은 가장 중요한 농업해충 중 하나이다. 식물 에센셜 오일은 살충 효과뿐만 아니라 섭식저해 효과도 나타내어 친환경적인 방제제의 잠재적인 후보로 간주된다. 본 연구에서는 29가지 에센셜 오일의 섭식저해 및 살충효과를 평가하였다. 또한, 습관화(habituation)와 미각 감각기관과의 연관성에 대한 가능성도 확인하였다. 3령 유충의 섭식저해력 및 살충력을 확인하기 위해 비선택성 시험과 접촉 및 훈증 시험을 진행하였다. 실험결과, 클로브 버드, 펜넬 스위트 및 레몬그라스 오일에서 뛰어난 효과를 보였지만 살충력과 섭식저해 간의 유의미한 상관관계는 확인하지 못하였다. 2령 유충은 이러한 활성 오일에 미리 노출되었다. 레몬그라스와 클로브 버드 오일에서 자란 유충은 미각 습관화가 나타난 반면, 펜넬 스위트 오일에서 자란 유충에서는 어떠한 둔감화도 나타나지 않았다. 3가지 오일의 주성분에서 자란 유충에서도 비슷한 결과를 확인할 수 있었다. 펜넬 스위트와 클로브 버드 오일의 이원 혼합물은 섭식저해 효과에 대한 상승효과를 나타냈다. 그러나, 통계적으로 유의하지는 않지만 혼합물에 대한 잠재적인 습관화가 관찰되었으며, 생리학적으로 높은 농도(FDI90+FDI90)에서만 강력한 습관화의 억제를 기대할 수 있었다. 전기생리학적 연구를 통해 citral에 대한 순응개체의 작은 턱수염(maxillary palp)의 반응은 감소하지만, transanethole에 대한 반응은 그대로 유지되는 것을 확인하였다. 이를 통해, 섭식저해의 감소는 에센셜 오일의 종류에 따라 달라지며 반복적인 노출과 maxillary palp의 둔감화에 의해 발생한다는 것을 밝혀내었다Abstract i Table of Contents iii List of Tables v List of Figures vii Introduction 1 Materials and Methods 5 1. Test insects 5 2. Test materials 7 3. GC-MS analyses 8 4. Bioassays 9 4.1. Feeding deterrent effect of essential oils 9 4.2. Contact and fumigation toxicity test 11 4.3. Synergistic feeding deterrence effect of binary mixtures of essential oils 12 4.4. Synergistic effect between the oils and major active constituents 13 5. Habituation tests 15 5.1. Pre-exposure to feeding deterrents 15 5.2. Two-choice test for habituation assay 16 5.3. Electrophysiological recording of gustatory sensillum 18 6. Stastical analysis 20 Results 21 1. Feeding deterrence and insecticidal activity of essential oils 21 2. Feeding deterrent effect of binary mixtures of essential oils 24 3. Chemical analyses of the essential oils 26 4. Dose-dependent response of the binary mixtures of essential oils and their major constituents 28 5. Habituation test for essential oils and their mixtures 31 6. Electrophysiological response of gustatroy sensillum 35 Discussion 37 Conclusions 45 Bibliography 47 Supplementary Materials 52 Abstract in Korean 78석

Single-molecule fluorescence study of recombination protein-DNA interactions

2

Directed Evolution of Glyceraldehyde-3-phosphate Dehydrogenase for Control-sensitive Glycolysis in E. coli

2