We analyzed the variation in occurrence time and intensity of attacks by the rice stem borer (Chilo suppressalis Walker) on several crops. We found similar occurrence patterns of C. suppressalis in different crops. Overwintering larvae showed no difference in pupal period and weight compared to the non-overwintering ones. However, the larval period was reduced to 19.1 days in Miscanthus field, in contrast to that in the paddy fields. Efficiency of the emergence trap was confirmed to be greater than that of the delta trap for capturing C. suppressalis adults. It is necessary to adjust the control period because of the advancement in occurring time of C. suppressalis in recent years. The larvae of C. suppressalis experience favorable environmental conditions for overwintering in Miscanthus fields. The results of this study provide important inputs for the development of environment-friendly control methods.

Tyrosine-mediated cuticle tanning (pigmentation and sclerotization) is a vital process for insect growth and development. In this metabolism, dopamine and N-β-alanyldopamine (NBAD) are major precursors to black melanin-like and yellowish quinonoid pigments, respectively. NBAD synthase (Ebony) catalyzes the synthesis NBAD by conjugation of dopamine and β-alanine, while NBAD hydrolase (Tan) dose a reverse reaction of NBAD synthesis catalyzed by Ebony. In this work, we cloned cDNAs of ebony and tan from two beetle species, Tribolium castaneum and Tenebrio molitor. Loss of function phenotypes produced by RNAi for these genes indicate that Ebony, but not Tan, is required for cuticle pigmentation in both beetles. This work was supported by NRFs (NRF-2015R1A2A2A01006614).

The eggs of Asian tiger mosquito, Aedes albopictus, possess high desiccation resistance, which could lead rapidly spreading this mosquito across the world. Melanization and/or hardening of mosquito eggshell are critical for desiccation resistance to protect embryo from adverse environment. Dopachrome-conversion enzymes (Yellows) catalyze melanin synthesis in insects. Here we report functional importance of two ovary-specific yellow genes, AalY-g and AalY-g2, in desiccation resistance of Ae. albopictus egg. Loss of function of these genes by RNAi causes the fragile exochorion and delay initial melanization of the endochorion. Furthermore, eggs from control females exhibit high desiccation resistance under the air-dry condition, whereas those from AalY-g- or AalY-g2-deficient females are collapsed. TEM analysis reveals ultrastructural defects in the endochorion and serosal cuticle in these eggs. The results indicate that AalY-g and AalY-g2 are critical for integrity and desiccation resistance of the Ae. albopictus egg.

Insect chitinases (CHTs), an extracellular enzyme, belong to family 18 glycosyl hydrolases that hydrolyze chitin by an endo-type manner. In insect genomes, there are a large number of genes encoding CHT-like proteins, and they have been classified into eleven groups based on phylogenetic analysis. In this study, we have investigated functions of a group III chitinase (TcCHT7) in Tribolium castaneum. Although, unlike most insect CHTs, TcCHT7 contains a predicted transmembrane segment in N-terminal, immunohistochemical analysis reveals that it is localized in the newly forming procuticle, suggesting that TcCHT7 is released from the plasma membrane of underlying epidermal cells. RNAi for TcCHT7 does not affect on any types of molting. However the resulting pupae and adults fail to undergo wing-expansion and abdominal contraction. In addition, TcCHT7-deficient insects exhibit ultrastructural defects in both rigid (e.g. elytron) and soft (e.g. hindwing) cuticles. These results demonstrate that functional importance of TcCHT7 in the formation of the rigid and soft cuticles of the beetle.

Chitin deacetylases (CDAs) are extracellular-modifying enzymes that deacetylate chitin to produce chitosan. Insect CDAs have been divided into five groups based on phylogenetic analysis. We previously reported the functional importance of group I CDAs, TcCDA1 and TcCDA2, from Tribolium castaneum in molting, morphology of cuticle as well as in movement of legs. However, ultrastructure in the cuticle after RNAi for these genes have not been investigated. In this study, we further analyzed precise localization of these proteins and ultrastructural changes/defects of the cuticles in TcCDA1- and TcCDA2-deficient insects. Loss of function of TcCDA1 and TcCDA2 causes disorganized horizontal laminae and vertical pore canals in both rigid (e.g. elytron and ventral body wall) and soft (e.g. hindwing and dorsal body wall) adult cuticles. These results indicate that TcCDA1 and TcCDA2 are critical for development and formation of the beetle cuticles

Insect cuticle/exoskeleton covering the entire external surface of the body is essential for protecting insects from various environmental stresses. Tyrosine metabolism plays a major role in not only the darkening of cuticle but also its hardening. In this work, we have focused on the functional analysis of nine genes involved in tyrosine-mediated cuticle tanning (pigmentation and sclerotization) pathway in Tenebrio molitor, which has a unique adult cuticle coloration, dark/black dorsal thorax and elytron, and reddish ventral thorax and abdomen. The temporal and spatial expression patterns of the genes were analyzed by real-time PCR, and RNA interference (RNAi) was performed to study the functional importance of these genes in cuticle coloration and/or hardening in T. molitor. This work was supported by NRFs (NRF-2015R1A2A2A01006614 and NRF-2015R1A6A3A04060323).

미국 민사소송절차에서 적법절차 논의는 법정지에 거주하지 않거나 법정지 와 실질적 관련이 없는 피고에 대해 “적법절차 요건(due process requireme nts)”을 충족하는 판단기준에 관한 것이다. 적법절차는 민사 소송을 당하는 비 거주자인 피고(non-resident defendant)가 다른 주의 법원, 정부권력으로부 터 부당하게 권리를 침해받지 않도록 피고를 보호하는데 우선을 둔다고 볼 수 있다. 이에 미국 연방법원은 타주(foreign state)의 법원이 비거주자 피고에 대해 재판관할을 행사하기 위해서는 해당 “피고,” 법정지(forum, 즉 타주의 법원), 분쟁사안과의 “minimum contact”이 있는 지를 검토한다. 법정지의 성문법상 법정지 법원의 재판관할권이 인정되는 경우에도 법정지 의 재판관할, 특히 인적재판관할(personal jurisdiction)에 대해서는 최종적으 로 미국연방헌법에서 보장하는 적법절차 요건에 부합한지에 대한 검토가 필요 하다. 미국 민사소송의 피고에 대한 적법절차요건은 재판관할관련 판례의 기 본원칙으로, 법정지의 재판관할 유무를 결정함에 있어 원고의 편의도 고려되 어야 한다는 반대의견에도 불구하고, 1945년의 International Shoe 판례 이 후 지금까지 변함없이 지속되고 있다. 2014년도의 미국 연방대법원의 재판관할에 대한 판례는 피고를 위한 적법 절차 요건을 재확인시켜주었다. 이에 논문은 미국 연방헌법에서 보장된 적법 절차가 법정지의 재판관할을 부인하는 비거주자 피고에게 어떻게 적용되는지 를 검토한다. 또한 우리 법원이 국제사법 상 “당사자(원고와 피고)”와 법정지 인 한국 법원과 실질적 관련성이 있을 경우 국제재판관할을 인정하는 점은 미 국이 피고를 기준으로, 피고와 법정지와의 실질적 관련성을 검토하여 재판관 할을 결정하는 점과 법적으로 약간의 차이가 있음을 지적해 본다.

The small brown planthopper (SBPH), Laodelphax striatellus, is one of the most serious pest insects of rice plants because it can transmit the rice stripe virus (RSV) which often causes significant reduction of yield in the field. Buprofezine is an effective insect growth regular (IGR) pesticide to control planthoppers, however, since the use of buprofezine for more than a decade, it has caused a certain resistance of SBPH. To survey the responses of SBPH to buprofezine, we exposed 4th instar SBPH to 200 ppm buprofezine by dipping method, and extracted total RNA for RNA-seq by Illumina platform. The quality filtered raw reads of cDNA obtained from experimental and control SBPH were subjected to Bowtie2 followed by eXpress computer program to compare the differential gene expression which will be important information for pest control methods using RNAi.

Varroa destructor is a devastating ectoparasitic mite which attacks Honeybee, Apis mellifera. V. destructor feeds on honeybee hemolymph, and often harbors small RNA viruses such as the deformed wing virus to transmit these viruses in the infested bee hive. To survey the genes of V. destructor, total RNA was subjected to high-throughput transcriptome sequencing to construct in silico cDNA library by using the Illumina HiSeq 2000 platform. Total of 2×107,748,792 paired-end short reads were obtained and quality filtered reads were subjected to Trinity de novo assembler followed by TransDecoder, and CD-HIT program to make a V. destructor reference cDNA library containing 28,023 of clustered contigs with protein coding capacity. These cDNA sequences will help us to understand the molecular biology of V. destructor.

Bacillus thuringiensis (Bt) produces a variety of insecticidal crystal proteins and widely used as one of the most successful biological control agents. Recently, studies that introduce cry genes into crops to create pest resistance have made much progress, and the total area of land planted with Bt crops has increased substantially. In this study, pest resistance of 8 transgenic Bt rice events with a synthetic cry1Ac gene linked to rice rbcS-tp sequence were assessed under laboratory conditions. Bioassays were performed against Cnaphalocrocis medinalis, which is a significant pest of rice in Asia. C. medinalis larvae were shown to be susceptible to all eight events, even though there were differences between the causes of death. The results differed between developmental stages of the larvae, despite the fact that all 8 events led to high mortalities. These results may be a significant foundation for the evaluation of improved transgenic Bt rice.

Insect growth regulators (IGRs) are attractive pest control agents due to their high target specificity and relative safety to the environment. Recently, plants have been shown to synthesize IGRs that affect the insect juvenile hormone (JH) as a part of their defense mechanisms. We identified several JH agonists (JHAs) and antagonists (JHANs) from plant essential oil compounds using a yeast two-hybrid system transformed with the Aedes aegypti JH receptor as a reporter system. They showed high mosquitocidal activities with relatively low LC50 values and caused retardation of ovarian development in female mosquitoes. While the JHAs increased the expression of JH-induced gene, the JHANs caused reduction in the expression of the same gene. The compounds identified in this study could provide insights on the plant-insect interactions and may be useful for the development of novel IGR insecticides.

Streptomyces is the largest genus of Actinobacteria that forms fungus-like branched networks of hyphae. Streptomyces has been clinically important because they produce various secondary metabolites with antibacterial, antifungal, and nematocidal activities. In order to explore novel insecticidal compounds, extracts from 363 strains of Actinobacteria were screened for their juvenoid and anti-juvenoid activities using yeast-two hybrid system. Among them, extract of Streptomyces spp. showed high anti-juvenoid activity. This extract also showed high level of insecticidal activities against larvae of Aedes albopictus, Laodelphax striatellus, and Ostrinia furnacalis. These results suggested that the secondary metabolites of Streptomyces could be natural sources of novel insecticidal compounds.

Entomopathogenic fungi have been widely studied for their potential as the effective biological control agents. They produce variety of secondary metabolites with insecticidal activities, and it is reasonable to assume that entomopathogenic fungi might produce secondary metabolites modulating juvenile hormone for their survival against defense mechanisms of host insect. In this study, Beauveria spp. and Lecanicillium spp. strains cultured on unpolished rice medium were extracted with acetone. Both extracts showed juvenile hormone antagonist (JHAN) activities in the yeast-two hybrid β-galactosidase assay. In addition, they showed high insecticidal activities against Aedes albopictus, Plutella xylostella, and Ostrinia furnacalis. These results suggested that secondary metabolites of entomopathogenic fungi could be useful for development of novel IGR insecticides.

Insect growth regulators (IGRs) are insecticides that disrupt the normal development of target insects by inducing symptoms such as premature molting or supernumerary larval stages. IGRs are categorized into three types based on their mode of action. One of the them is classified as juvenile hormone agonists (JHAs). In recent studies, we identified juvenile hormone antagonists (JHANs) from plant extracts. In order to identify a novel juvenile hormone agonists and antagonists, we tested 2,354 chemical compounds using the yeast-two hybrid system. Among them, 2 JHAs and 4 JHANs were selected and their insecticidal activities were evaluated against Aedes albopictus larvae. These results may be useful for development of novel IGR insecticides.

Arsenic (As) is a toxic element that easily taken up by plants root. Several toxic forms of As disrupt plant metabolism by a series of cellular alterations. In this study, we applied annealing control primer (ACP)-based reverse transcriptase PCR (polymerase chain reaction) technique to identify differentially expressed genes (DEGs) in alfalfa roots in response to As stress. Two-week-old alfalfa seedlings were exposed to As treatment for 6 hours. DEGs were screened from As treated samples using the ACP-based technique. A total of six DEGs including heat shock protein, HSP 23, plastocyanin-like domain protein162, thioredoxin H-type 1 protein, protein MKS1, and NAD(P)H dehydrogenase B2 were identified in alfalfa roots under As stress. These genes have putative functions in abiotic stress homeostasis, antioxidant activity, and plant defense. These identified genes would be useful to increase As tolerance in alfalfa plants.

Copper (Cu) is a necessary microelement for plants. However, high concentrations of Cu are toxic to plants that change the regulation of several stress-induced proteins. In this study, an annealing control primer (ACP) based approach was used to identify differentially expressed Cu-induced genes in alfalfa leaves. Two-week-old alfalfa plants (Medicago sativa L.) were exposed to Cu for 6 h. Total RNAs were isolated from treated and control leaves followed by ACP-based PCR technique. Using GeneFishing ACPs, we obtained several genes those expression levels were induced by Cu. Finally, we identified several genes including UDP-glucuronic acid decarboxylase, transmembrane protein, small heat shock protein, C-type cytochrome biogenesis protein, mitochondrial 2-oxoglutarate, and trans-2,3-enoyl-CoA reductase in alfalfa leaves. These identified genes have putative functions in cellular processes such as cell wall structural rearrangements, transduction, stress tolerance, heme transport, carbon and nitrogen assimilation, and lipid biosynthesis. Response of Cu-induced genes and their identification in alfalfa would be useful for molecular breeding to improve alfalfa with tolerance to heavy metals.

Insect chitinases (CHTs) belong to family 18 glycosylhydrolases and hydrolyze chitin by an endo-type manner. One of the functions of CHTs is in the turnover of chitin-containing extracellular matrices such as the cuticle and peritrophic matrix of the midgut. There are a large number of genes encoding CHT-like proteins in insects, and they have been classified into eleven groups based on phylogenetic analysis. We have investigated functions of a group III chitinase in Tribolium castaneum (TcCHT7) containing a predicted transmembrane segment in N-terminal region. Recombinant TcCHT7 exhibits chitinolytic activity against CM-Chitin-RBV. Immunohistochemical analysis shows that TcCHT7 is localized in newly formed procuticle in elytral cuticles, suggesting that TcCHT7 is released from the plasma membrane of underlying epidermal cells. TcCHT7-deficient pupae and adults fail to undergo wing-expansion and abdominal contraction. In addition, cuticular chitin accumulates in the inner region of the procuticle where disorganized horizontal laminae and pore canals are evident. These results demonstrate that TcCHT7 plays a critical role in the formation of the rigid and soft cuticles of the beetle. This work was supported by NRFs (NRF-2015 R1A2A2A01006614).