초록 ▼

Ⅳ. 연구개발결과
제1세부연구과제 :남방계 주요 3종 나방류의 행동반응 분석 및 피해해석
○ 일반적으로 식식성 곤충은 매우 다양하며 또 개체수가 상당히 풍부
○ 대개 곤충은 그 종수가 진핵생물의 1/4 이상을 차지할 정도로 다양하다. 그리고 그들은 식물체의 잎, 줄기, 뿌리, 즙액, 꽃가루 등 거의 모든 것들을 섭식한다. 따라서 온도별 섭식량을 조사하는 것은 향후 기후변화에 따른 이들 남방계해충의 피해량 해석에 밀접히 연관될 수 있으며, 잎의 시들음 현상을 측정하여 표에 실었다. 배추좀나방, 담배나방, 파밤나방은 2

Ⅳ. 연구개발결과
제1세부연구과제 :남방계 주요 3종 나방류의 행동반응 분석 및 피해해석
○ 일반적으로 식식성 곤충은 매우 다양하며 또 개체수가 상당히 풍부
○ 대개 곤충은 그 종수가 진핵생물의 1/4 이상을 차지할 정도로 다양하다. 그리고 그들은 식물체의 잎, 줄기, 뿌리, 즙액, 꽃가루 등 거의 모든 것들을 섭식한다. 따라서 온도별 섭식량을 조사하는 것은 향후 기후변화에 따른 이들 남방계해충의 피해량 해석에 밀접히 연관될 수 있으며, 잎의 시들음 현상을 측정하여 표에 실었다. 배추좀나방, 담배나방, 파밤나방은 27℃ 부근에서 가장 활발한 먹이 섭식 행동을 보여주었다.
제2세부연구과제 :미소해충의 분포한계와 기후변화 영향분석
○ 분포범위 확산
꽃노랑총채벌레와 오이총채벌레의 북방한계선 북상
이번 조사에서는 과거 꽃노랑총채벌레와 오이총채벌레의 노지에서의 북방한계선이 노령산맥이남 즉 충남이남으로 보고되고 있었으나, 3년 동안의 조사결과 꽃노랑총채벌레나 오이총채벌레류의 남한에서 분포 북방한계선은 존재하지 않는 것으로 드러났다.
○ 노지포장에서 총채벌레류의 최우점종
전국적으로 대만총채벌레가 압도적인 우점현상을 보였다(약, 85%).
○ 총채벌레류 방제전략
노지에서의 총채벌레류의 방제는 대만총채벌레류를 우선으로 하여 기타 좀머리, 꽃노랑, 오이,관총채벌레 등의 순으로 관리 전략을 수립하면 될 것으로 판단된다.
제1협동연구과제 : 남방계 곤충의 확산 지표마커 개발과 상관성 분석
○ 곤충의 내한성
저온 전처리 시간에 비례하여 생존율이 증가하였으며, 이러한 내한성 증가는 혈림프 내의 glycerol과 Trehalose 함량의 증가에 의한 것이다. glycerol 및 trehalose 관련 유전자 발현 억제는 곤충의 내한성 억제로 나타나 치사율을 증가시켰다
○ 곤충의 발육관련 유전자
파밤나방의 발육 영점온도는 2-11°C로 측정되었고, 대사, 신경, 면역, 스트레스 관련 유전자 발현변화를 검정하였다. 5령 유충의 온도별 유전자 발현은 chitinase synthase를 제외하고 발현이 증가하였고, 온도처리기간이 증가할수록 발현변화가 강하였다.
○ 곤충의 발육시기별 저온 생존
알을 제외하고 각 령기별 생존의 차이는 있지만 파밤나방의 경우, 유충이나 번데기 시기에 저온에서 생존이 가능한 것으로 확인하였다 저온 생존애에 영향을 주는 Hsp 70에 대한 유전자발현 억제를 통해 이 단백질의 발현억제가 생존율을 낮춘다는 것을 확인하였다.
○ 곤충의 내열성
고온노출에 의한 파밤나방의 내열성은 1령 유충이 높은 경향을 보였다. 고온 전처리에 의한 생존율도 4령 유충보다는 1령 유충이 더 높았다. 열충격 단백질의 발현 패턴을 확인하였을 때 Hsp 70, Hsp 74, Hsp 84 모두 고온 전처리 유충에서 발현 수준이 증가함으로써 고온에서 생존율에 영향을 준 것으로 보인다.
○ 발현유전체
파밤나방과 담배나방에서 upregulation 되는 유전자와 downregulation 유전자를 동정하였다.파밤나방의 경우, triacylglycerol lipase의 유전자 발현억제는 4령기의 발육기간을 단축시킨 반면, Senecense associated Protein, RP S14 유전자는 오히려 발육기간을 증가시켰다. 담배나방과 배추좀나방의 지방체 발현전사체는 저온에서 구조단백질, 지질대사관련 효소 발현이 증가하였고, 고온에서는 스트레스단백질. 항산화효소 발현이 증가하였다.
제2협동연구과제 : 열대·아열대지역 유래 곤충매개 병원성 미생물의 유입 및 작물피해예측
○ 열대, 아열대 지역의 곤충매개 병원성 미생물 DB 수립
○ 아시아 열대지역의 곤충 미생물 군집과 비교한 결과 한국에는 존재하지 않는 병원성 미생물이 존재함.
- 병원성 진균의 유입이 가장 우려된다.
○ Tri-trophic 동역학 모델에 의하여, 작물밀도와 서식지 연결성이 유입병원체의 토착화와 지리적 확산이 민감한 요인으로 나타남
- 논의 연결성과 면적이 넓어서 벼가 가장 외래 해충 및 병원체 유입에 취약한 작물이지만 유입의 빈도가 낮을 수 있다. 또한 국내의 총채벌레의 유전형으로 살펴본 국내 원예작물 해충의 서식지의 연결성은 매우 높으며, 동해안과 산간지역은 가장 교류가 적은 것으로 나타났다.
○ 따라서 작물재배 밀도의 조절, 재배지간 단절성 확보 등의 제어 방법이 될 수 있음.

Abstract ▼

Generally, phytophagous insect pests are very diverse and numbers of each phytophagous insect pest exists abundantly in the agricultural ecosystem. Insects occupies over 50% of eukaryotic organisms and phytophagous insects digest leaves, root, stem, and pollens etc. Currently, climate changes can af

Generally, phytophagous insect pests are very diverse and numbers of each phytophagous insect pest exists abundantly in the agricultural ecosystem. Insects occupies over 50% of eukaryotic organisms and phytophagous insects digest leaves, root, stem, and pollens etc. Currently, climate changes can affect whole biological and physical conditions of biospheres.Therefore, assessment of feeding amount at each examined temperature can be related to understanding crop damage pattern of southern-origin insect pest under the influence of climate change in Korea. the examined insect pests, Plutella xylostella (L.), Heliocoverpa assulta (Guenée) and Spodoptera exigua (Huber), exhibited the highest feeding activities at 27℃. Theses results can be applicable to the prediction of damage of Chinese cabbage and pepper.
The distribution of the small-sized insect pests such as thrips can reflect the on-going climate change. We surveyed the distribution of thrips in Korea and analysed the pattern of these thrips. The distribution limits of Western flower thrips, Frankliniella occidentalisi and Palm thrips, Thrips palmi have moved toward to the North, suggesting these thrips can exist in northen Korean peninsula. F. intonsa is a predominant species in Korea and their collection ration is approx. 85%. To make an effective control these thrips, the sequence of main control target should be F. intonsa, T. palmi , and F. occidentalisi.
To understand cold tolerance of southern-region insects, supercooling point (SCP), several experiments such as cold tolerance of different developmental stages, post-rapid cold hardness induction, and survival rate of extremely low temperature after mild-cold exposure were performed. All examined insects showed lower SCP when they are pre-incubated with RCP. RCH was dependent on the duration of the pre-exposure period. RCH also significantly enhanced the supercooling capacity. Cryoprotectant analysis using HPLC showed that the pre-exposure treatment allowed the larvae to accumulate glycerol in the hemolymph of Spodoptera exigua and Helicoverpa assulta. Two genes, glycerol-3-phosphate dehydrogenase (GPDH) and glycerol kinase (GK), were identified as being associated with glycerol biosynthesis, and were cloned from S. exigua and H. assulta larvae. qRT-PCR analysis revealed that only GPDH1 expression was increased when H. assulta larvae was pre-exposed to low temperature. Both GPDH and GK were expressed in all developmental stages of S. exigua. RNA interference (RNAi) of either GPDH or GK significantly inhibited glycerol accumulation in the hemolymph of S. exigua. Larvae treated with RNAi for GPDH or GK exhibited a significant decrease in RCH capacity. The glycerol accumulation in response to 4℃ appeared to be under the control of a humoral signal, because a ligation experiment prevented glycerol accumulation in the other half of the body.
To understand the physiological status of the beet armyworm, S. exigua at low developmental threshold temperature (LTT) through analysis of gene-expression patterns associated with different functions (metabolism, nervous system, immune, and stress). The estimated LTTs for egg, larval, and pupal developments varied with 5.5 ~ 11.6℃. Larvae were able to develop at the lower temperatures than eggs and pupae. However, the physiological LTT (15℃) in the fifth instar was much higher than the estimated LTT (10. 3℃). Gene expression patterns estimated by a quantitative RT-PCR (qRT-PCR) indicate that most genes in different functional groups increased their expressions with increase of larval instars. In the same fifth instar, as the treatment temperatures increased, the gene expression levels increased. Moreover, the newly molted fifth instar larvae were different in their gene expression rates according to their previous culturing temperatures. Most gene expressions were suppressed in the fifth instar larvae at the physiological LTT (15℃).However, the larvae at 15℃ gradually exhibited significant increase in the gene expression rates with rearing time just like those at the higher temperature. In addition, heat-shock proteins were somewhat involved in the tolerance against low temperature. Cold tolerance of S. exigua was decreased when RNAi of hsp70 was applied. suggesting hsp are closely related to the cold tolerance.
Temperature is one of important environmental factor affecting insect development. To examine genetic factors involving developing of S. exigua larvae against temperature change, based on the low developmental threshold temperature (LTT), gene expression of individual rearing at different temperatures (20, 25, 30℃) was compared. 3,667 contigs were identified from approximately 40 Gb. K means analysis revealed 4 different gene patterns: high temperature and increase gene expression (positive correlation: 51.2%), high temperature and decrease gene expression (negative correlation: 3.1%) and others, weak increase or decrease of gene expression (45.7%). To analyze the gene function, 4 and 5 genes are selected from positive and negative correlation, respectively. development-inhibitory genes are annotated: Comp49 (β-actin), Comp78 (cuticle protein), Comp91 (diapause-specific protein), and Comp204 (triacylglycerol lipase).Development-stimulating genes are annotated: Comp0 (senescence-associated protein), Comp7 (Repat 10), Comp8 (putative cuticle protein), Comp14 (RP S10) and Comp15 (RP S14). When Comp78 and Comp204 were suppressed via RNAi. development was stimulated at 26℃ whereas RNAi of Comp49 and Comp91 did not any difference with control. When Comp0 and Comp14 was inhibited, development was delayed. RNAi of Comp7 and Comp8 have no effect on development.
The diamondback moth, P. xylostella, overwinters in some protected areas in Korea. Using a sex pheromone trap, the adults were monitored since the occurrence of the overwintering populations. In Andong, P. xylostella exhibited four adult peaks in a year. Biological characters, such as cold tolerance, insecticide susceptibility, and developmental rate, were analyzed and showed a significant variation among different local overwintering populations. Population genetic variation was assessed with molecular markers, in which the initial high genetic variation among the overwintering populations decreased with the progress of seasons. These results suggests that there may be a significant migration of P. xylostella to decrease the genetic variation among the different local populations that are different in biological characters.
To find factors or genes contributing to distribution of cold or heat tolerance, transciptomes of P. xylostella and H. assulta larvae have been performed. In P. xylostella, some genes such as cuticular proteins, chitinase, actin, glutathione S transferase, fatty acid desaturase and phospholipase A2 were much higher expressed in cold-treated larvae whereas heat shock protein, catalase and cytochrome P450 much higher expressed in heat-treated larvae.In H. assulta, some genes such as cuticular proteins, metallothionein 2, fatty acyl delta9 desaturase, phospholipase A2, phosphoenolpyruvate carboxykinase, trehalose transporter were much higher expressed in cold-treated larvae whereas heat shock protein, superoxide dismutase, gluthathione peroxidase, cytochrome P450, metallothionein 2 and trehalose transporter much higher expressed in heat-treated larvae. These results suggest that genes specifically expressed at high or low temperature can be applicable to the indicator of insect adaptation for climate changes.
Due to climate change, tropical crops has increased cultivation rate in Korean. Agricultural productivity has decreased according to the change of crops and fruit trees in agricultural ecosystems. Predictive assessment of crop loss is a need to predict the domestic disseminations and naturalization of southern-origin insect pathogen. The purpose of this study is predictive assessment of crop loss due to domestic disseminations of tropic-origin insect pathogen. Literature investigation research and sampling in the field was conducted in order to research. The results of analysis of the microbiome of thrips that live in 7 countries, found 13～744 species for each country the pathogenic microorganisms that are not present in the microbial community of Korea thrips. Fungal communities, to very different in Korea and other countries, it was found that the inflow of pathogenic fungi is most concerned. By Tri-trophic dynamics model, connection of habitat and crop density of indigenization and the geographical spread of the inflow pathogen has become a sensitive factor. In the case of rice, it became vulnerable crops to the inflow of large cultivation area and the most exotic pests and pathogens for the connection of farmland. In the case of horticultural crops, it has been analyzed habitat connectivity through microsatellite analysis of domestic thrips. As a result, ecological connectivity of the Youngnam, Honam and Chungcheong plain understand to be very high except the East Coast and mountainous territory. It may be used to control method by extending crop density or disconnection between field in order to damage reduce.