During the larval development process of insects, juvenile hormone (JH) is essential for regulating various aspects of larval life, including growth, reproduction, and behavior, throughout their larval stage. The larval stage of Spodoptera frugiperda, when it consumes plant-derived metabolites, develops into pupae, but these pupae are unable to molt successfully. In this way, plant-derived metabolites contain or produce inhibitors of juvenile hormone, thereby disrupting the development of insect larvae and making them vulnerable to harm. Therefore, in this study, we established an in vitro screening system using yeast cells transformed with the Met-SRC juvenile hormone receptor of S. frugiperda. Through this system, we were able to identify juvenile hormone disruptors from plant-derived metabolites and confirm their developmental inhibitory effects on the larvae of S. frugiperda.

담배거세미나방(Spodoptera litura), 열대거세미나방(Spodoptera frugiperda) 및 파밤나방(Spodoptera exigua) 은 광식성 해충이지만, 종특이적인 기주범위를 갖는다. 이들이 기주식물을 찾아가는 과정에 냄새감각이 어떤 역할을 하는지 알아보기 위해, 기주 및 비기주 식물에서 발산되는 46가지 휘발성 물질을 선정하여, 이들에 대한 나방 3종의 냄새반응을 GC-EAD(gas chromatography-electroantennogram detection)를 통해 확인하였다. 그 결과, 46가지의 식물유래화합물 중 9가지 물질이 3종의 나방 모두에서 냄새활성을 나타냈으며, 2가지 물질은 담배거세 미나방과 열대거세미나방에만 냄새활성을 나타냈고, 다른 몇 가지 물질은 담배거세미나방에만 냄새활성을 나 타냈다. 이 결과는 세 종 나방이 식물냄새물질 탐지를 위해 유사한 냄새감각세포를 가지며, 일부 종에서는 종특이 적인 냄새감각세포가 존재한다는 것을 보여준다. 이 결과를 바탕으로 냄새활성을 나타낸 물질들의 나방 3종에 대한 행동활성을 야외트랩실험을 통해 확인할 예정이다.

Despite rising global concerns over the potential impacts of invasive alien species on indigenous species, the consequences of such introductions are lacking. The cabbage seedpod weevil (CSPW, C. obstrictus) was introduced into Korea in the early of 1990s. There was no genetic differences of COI sequences between populations of invasive CSPW, while was 1.1 % between populations of native rapeseed weevil (RSW, C. albosuturalis). It is tentatively considered that CSPW spread from once invasive population to the whole country. A large-scale survey in Korea reveals that, in about 20 years post-arrival, the invasive CSPW has become the most abundant on rape flowers and spread almost parts of South Korea including Is. Jeju and Is. Ulleung. Its spread is concurrent with the geographic retraction of the native RSW. However, Is. Yeoseo located between the mainland and Is. Jeju, was showed their ratio with 1:1. It suggests that the population of CSPW recently entered this island. Although the decline’s underlying mechanisms remain unknown, the potential roles of exploitative competition cannot be ruled out. Given that invasive weevil can rapidly replace native congeners, further introductions of other insect pests should be discouraged.

Insect infestation leads to huge loss of agricultural products and transmission of vector-borne diseases causing millions of deaths per annum. Juvenile hormone (JH) controls the development and reproduction of insects, therefore the grouth of insects can be inhibited by interfering the action of JH. Based on this, we developed a novel insect species-specific screening system to identify juvenile hormone antagonists (JHANs) from natural origin. These compounds can disrupt JH-mediated insect development by interfering the binding of a heterodimer, steroid receptor coactivator (SRC), with its partner protein, the methoprene-tolerant (Met) JH receptor. This screening system could be used as a new tool to develop eco-friendly and species-specific insecticides.

The Plant Extract Bank was established by 21 Century Frontier R&D Program. It has began selling a research plant extract samples to support many Korean scientists since 2001. The plant extracts were tested for insecticidal activities. A total of 19,100 ethanolic and methanolic extracts of differentplant species from 23 nations including Costa Rica, Philippines, India and South Africa were evaluated for their larvicidal activities against Aedes aegypti, the major vector of dangue, dangue hemorhagic fever and yellow fever. The larval mortalities were observed 24h after treating the larvae to the extracts. At 500 ppm, 754 extracts showed >80% larval mortality in the 24h exposure. Among the extracts tested, the highest larval mortality was observed in the methanol extracts of Piper guianense, P. nigrum, P. mocropodum, P. sem-immersum, P. magen and P. pubicatulm.

Insects impact human health through vector-borne diseases and cause major economic loses through damaging crops and stored agricultural products. Insect-specific growth regulators (IGR) represent attractive control agents because of their safety to the environment and humans. Here, we report identification of plant compounds that are antagonists of the insect-specific juvenile hormone (PJHANs), using the yeast two hybrid system transformed with the mosquito JH receptor as a reporter assay. We show that these compounds act by inhibiting larval growth and reproduction in mosquitoes. We also demonstrate that PJHANs affect the JH receptor, Methoprene-tolerant (Met), by disrupting its complex with CYCLE, formation of which is required for mediating JH action. We isolated five diterpene secondary metabolites with JH antagonist activity from two plants, Lindera erythrocarpa and Solidago serotina. They are effective in causing mortality of mosquito larvae at relatively low LD50 values. Two of these diterprenes affect Met function, leading to reduction in expression of Met target genes and causing retardation of follicle development in mosquito ovaries. Developing potent compounds counteracting JHaction (JH antagonists) would find a wider range of control applications. However, so far such JH antagonists have not been developed. Here, we report the discovery of potent JH antagonists in plants, which represents an innate resistance mechanism of plants against insect herbivores. These newly discovered plant JH antagonist compounds could be used as the starting material for developing novel insecticides.

발아기를 전후한 이상기후로 감나무의 신초 생장이 늦어지는 경우가 많다. 본 연구는 봄철의 생장 지연이 ‘부유’의 신초 및 과실 생장에 미치는 영향을 파악하고자 수행되었다. 신초 생장 지연을 유도하기 위해 탈순화 과정에 있는 눈의 온도조건을 달리하였는데, 발아 전인 3월 12일부터 정상 나무의 발아3일 후인 4월 8일까지 3~4년생 측지에 폴리에틸렌 비닐주머니를 씌우는 방법으로 하였다. 비닐주머니를 설치했던 가지는 낮 온도가 2~5℃ 높아진 반면 밤 온도는 외기온과 같아 주야간 온도변화 폭이 커졌고, 그 결과 4월 동안 발아와 신초 생장 지연 정도가 달라졌다. 4월 27일에 길이 0.5~10 cm 범위의 신초를 30개 선정하여 길이를 측정하고 각각의 생장을 추적 조사하였다. 생장 지연이 심한 신초일수록 개화가 늦어 7일까지 차이가 있었고 엽장이 짧아졌으나 신장이 종료된 신초장은 차이가 없었다. 신초 생장 및 개화가 지연될수록 수확 과실의 크기가 작아진 반면, 색도, 경도, 당도는 유의적인 변화가 없었다.

Rapid identification of pest species found under quarantine is an important factor in preventing an economic loss of agricultural commodities. In this study, we analyzed RNA-Seq of the larvae of C. sasakii, G. molesta and G. dimorpha, which are serious pests in several fruits in Korea and are difficult to discriminate by species in their larval stage because of lack of a morphological character. To select immunological diagnostic markers, discriminating the larvae of C. sasakii from the G. molesta and G. dimorpha, RNA-Seq was performed for the larvae of the three insects. The 454 pyrosequencing generated 3,058-4,686 contigs for each three pest species, which assembled into 2,584-3,970 isotigs with average lengths of 829-1,244 bp. Functional annotation of the sequencing results generated 774 orthologs for the three pest species, and 12 isotigs were finally registered as candidate markers for species discrimination through bioinformatical screening, literature search, and gene expression study. The selected candidates include serine proteases, serpins, 27 kDa glycoprotein and storage protein with a constitutive gene expression in their larvae, pupae and adult stage.

본 연구에서는 팥의 꼬투리와 줄기를 가해하는 Ostrinia속 해충에 대해 종 동정 과정을 기술하였고, 사육하면서 관찰된 발육특성들을 보고 하였다. 수컷의 생식기는 3-lobed uncus 형태였으며, 가운뎃다리 종아리마디에는 털을 많이 갖는 것으로 나타났다. 미토콘드리아 cytochrome oxidase I (COI)과 II (COII) 유전자의 부분 염기서열은 콩줄기명나방(O. scapulalis), 큰섬들명나방(O. zaguliaevi), 큰조명나방(O. zealis bipatrialis)들에 대해 일본과 중국에서 보고된 서열들과 100% 일치를 보이는 종은 없었다. 기주식물 범위는 국내외 보고들 간에 일치하지 않았다. 암컷 성페로몬샘 추출물의 가스크로마토그래피 분석에서 큰섬들명나방과 큰조명나방의 성페로몬 성분인 (Z)-9-tetradecenyl acetate는 검출되지 않았다. 이상의 결과들을 종합하여 고려하였을 때, 본 연구의 팥 해충을 가해하는 곤충 종은 콩줄기명나방(O. scapulalis)일 것으로 추정되었다. 가을 야외에서 채집된 유충들을 야외조건에서 보관하였을 때, 이듬해 6월과 7월 사이에 성충들이 우화하였는데, 이 결과로부터 본 곤충 종은 말령 유충 단계에서 겨울휴면을 하는 것으로 추정되었다. 이외에 반합성 인공사료를 이용하여 실내 사육이 가능하였다.

This study was conducted to identify an insect species in Genus Ostrinia (Lepidoptera: Crambidae) that gave serious damage to the red bean, Vigna angularis. The species has ever been described as O. zaguliaevi in the previous presentation (Jung et al., 2010). Because, however, inconsistent information has been recognized for the species, we reviewed characteristics in morphological, molecular and sex pheromone levels, and host-range. Male genitalia had 3-lobed uncus and tibia of midleg showed massive type. The morphology indicated that the species might be one of O. zaguliaevi, O. scapulalis and O. zealis. Partial nucleotide sequences of cytochrome oxidase subunit Ⅰ(COⅠ) and Ⅱ genes were not identical with those of the 3 species in GenBank, respectively. The deduced amino acid sequence of COⅠ was not identical with that of O. zealis. In the 23 analyses that sex pheromones were checked, (Z)-9-tetradecenyl acetate, which was reported in the sex pheromone components of both O. zaguliaevi and O. zealis, was not detected at all. An intensive study in Japan has reported that the feeding habit of O. scapulalis is polyphagous, while that of O. zaguliaevi is monophagous (only in Petasites japonicus) (Ishikawa et al., 1999). After considering all these information, we concluded that it is reasonable to decide that the insect species in the red bean in Korea is O. scapulalis.