Bt efficacy against the diamondback moth, Plutella xylostella, larvae immunosuppressed by expression of viral ankyrin genes encoded in a polydnavirus, Cotesia plutellae bracovirus

Kyusoon Kim,Hyun Kim,Kilha Kim,Yonggyun Kim 한국응용곤충학회 2012 한국응용곤충학회 학술대회논문집 Vol.2012 No.10

Parasitism by an endoparasitoid wasp, Cotesia plutellae, results in significant immunosuppression of the diamondback moth, Plutella xylostella. Parasitized larvae significantly suffered higher susceptibility to a microbial biopesticide, Bacillus thuringiensis (Bt) than nonparasitized (NP) larvae. To find out an immunosuppressive agent causing the enhanced Bt efficacy, viral ankyrin (=vankyrin) genes encoded in C. plutellae bracovirus (CpBV) were analyzed by transient expression in NP larvae. CpBV segments containing different vankyrins were microinjected to NP larvae and expressed their encoded vankyrins. Expression of some vankyrins significantly inhibited immune response and enhanced Bt efficacy. This study suggests that expression of vankyrins suppress a cellular immune response and lose Bt tolerance of P. xylostella larvae.

Identification of a Cys-motif Gene, TSP13, as a Putative Host Translation Inhibitory Factor in Plutella xylostella-Cotesia plutellae

Eunseong Kim,Yeongtae Kim,Yonggyun Kim 한국응용곤충학회 2015 한국응용곤충학회 학술대회논문집 Vol.2015 No.04

Translational control is a strategy for various viruses to manipulate their hosts to suppress any acute antiviral activity. Some cys-motif genes encoded in polydnaviruses or teratocytes act as host translation inhibitory factor (HTIF) to defend the host antiviral activity. A novel cys-motif gene, TSP13, was encoded in the genome of an endoparasitoid wasp, Cotesia plutellae. TSP13 consists of 129 amino acid residues with a predicted molecular weight of 13.987 kDa and pI value at 7.928. Genomic DNA region encoding open reading frame is interrupted with three introns. TSP13 was expressed in Plutella xylostella larvae parasitized by C. plutellae. C. plutellae bracovirus (CpBV) was purified and injected to nonparasitized P. xylostella. In the virus-injected P. xylostella, TSP13 was shown to be expressed by RT-PCR analysis. Thus, TSP13 was turned out to be encoded in the proviral CpBV genome. TSP13 was cloned into a eukaryotic expression vector, which was then used to infect Sf9 cells to transiently express TSP13. The synthesized TSP13 was detected in the culture broth. Purified TSP13 significantly inhibited cellular immune responses. Furthermore, TSP13 entered the target cells and was localized in the cytosol. This study reports a novel cys-motif gene, which is encoded in CpBV genome localized on chromosome(s) of C. plutellae and replicated to be encapsidated in the episomal viral particles during parasitization.

Bactericidal Effects of Metabolites Synthesized by Two Entomopathogenic Bacteria, Xenorhabdus nematophila and Photorhabdus temperata temperata, against Plant Pathogens

Minjae Kim,Jeamin Kim,Yessl Park,Yonggyun Kim 한국응용곤충학회 2009 한국응용곤충학회 학술대회논문집 Vol.2009 No.05

Two entomopathogenic bacteria, Xenorhabdus nematophila (Xn) and Photorhabdus temperata temperata (Ptt), maintain monoxenic condition within host insect cadaver by synthesizing and releasing various antibiotics. These two bacteria were cultured in tryptic soy broth during different times, which were screened in their antibacterial activities. Both bacterial culture broth had high antibacterial activities against Escherichia coli at their stationary growth phase. The potent culture broth was used to screen target plant bacterial pathogens using both inhibition zone assay and liquid culture assay. Ralstonia sp. was most susceptible, while Xanthomonas sp. was highly resistant. Pseudomonas sp. and Bacillus sp. showed hemi-susceptible. The culture broth was further fractionated into hexane and diethylether extracts. Significant antibacterial effect was found in the diethylether extract

Antixenosis of hot pepper against the western flower thrips, Frankliniella occidentalis

Yonggyun Kim,Chulyoung Kim,Hyunje Park,Falguni Khan,Daehong Lee,Gahyun Jin,Hee-Jin Kim,Hyungwoo Choi,Yongho Jeon 한국응용곤충학회 2023 한국응용곤충학회 학술대회논문집 Vol.2023 No.10

꽃노랑총채벌레(Frankliniella occidentalis)는 고추를 가해하는 주요 병해충 가운데 하나이다. 유충과 성충이 긁어빠는 구기로 잎과 열매에 가해하는 직접피해는 물론이고 일명 칼라병이라 일컬어지는 토마토반점위조바 이러스를 전파하는 간접피해를 주고 있다. 다양한 바이러스 내병성 품종이 농가에서 재배되고 있으나, 칼라병의 발병은 해를 거듭하며 증가하고 있다. 놀라운 사실은 일부 내병성 품종에 대해서 총채벌레의 유인력이 감수성 품종에 비해 높다는 사실이다. 본 연구는 꽃노랑총채벌레에 대한 고추의 항객성 기작을 분석하였다. 총채벌레에 이미 피해를 받은 고추는 다른 총채벌레의 접근을 억제하는 것은 물론이고 천적인 미끌애꽃노린재를 유인하였 다. 이 고추 내부에는 자스모닉산 생합성 관여 유전자의 발현이 증가하였다. 고추가 생산하는 향기성분을 SPME 방식으로 모아 분석한 결과 Green leaf volatile과 terpene류의 증가를 보였다. 시판되는 10개의 고추 품종을 대상으 로 항객성 생물 검정과 향기성분 분석을 실시한 결과 이상의 항객성 기작을 뒷받침하였다. 또한 근권세균 가운데 일부는 고추로 하여금 이러한 항객성을 유도하였다.

Genetic Difference Between Two Field Populations of Plutella xylostella (Linne) Based on Four Polymorphic Allozymes

Kim, Yonggyun,Kim, Kyungwon,Kim, Namkyu Korean Society of Applied Entomology 1999 Journal of Asia-Pacific Entomology Vol.2 No.1

We analyzed the breeding structure of the field diamondback month, Plutella xylostella (Linne), populations. Four polymorphic allozyme loci of acid phosphatase, esterase-1, hexokinase, and phosphoglucomutase were used for the population genetic markers. The estimated genetic distance between Andong and Sangju populations (ca. 50km apart) ranged from 0.0215 by fixation index(${F}_{ST}$) to 0.0550 by Nei's genetic distance(D). Such a little genetic differentiation between these two populations is explained by the significant migrants (11.5 per generation per population) which are estimated by Wright's method(${N}_{eM}$).

Inhibitory Effect of a Polydnavirus, Cotesia plutellae Bracovirus, on Larva-to-pupa Metamorphosis of Plutella xylostella

Yonggyun Kim,Jiwan Kim 한국응용곤충학회 2012 한국응용곤충학회 학술대회논문집 Vol.2012 No.05

Parasitization by an endoparasitoid wasp, Cotesia plutellae, extends a larval period of Plutella xylostella and inhibits a larva-to-pupa metamorphosis. To determine antimetamorphic parasitic factor(s) in this host-parasitoid interaction, an effect of its symbiotic polydnavirus, Cotesia plutellae bracovirus (CpBV), was investigated by injecting purified virus particles to nonparasitized larvae of P. xylostella. Larvae injected with CpBV exhibited antimetamophosis in a viral dose-dependent manner. Also, the susceptibility to the viral injection was increased at young larval stages. Parasitized or virus-injected larvae shwed significant decrease in cell size of prothoracic gland and reduction in expression of ecdysone receptor (EcR) gene. However, they increased and maintained expression of insulin receptor (InR) gene. Twenty four CpBVsegments were individually injected to nonparasitized larvae. Only two segments (S22 and S27) had significant antimetamorphic effect. Subsequent RNA interference using double stranded RNA (dsRNA) was performed in each of encoded genes in each segment. Protein tyrosine phosphatase, ELP, and three hypothetical genes were determined to be antimetamorphic factors.

A Novel Bt-Plus Development to Control the Brassica Leaf beetle, Phaedon brassicae

Eunsung Kim,Youngjin Park,Yonggyun Kim 한국응용곤충학회 2015 한국응용곤충학회 학술대회논문집 Vol.2015 No.04

Cabbage is one of the major vegetable crops especially in Korea. Various insect pests intimidate the cabbage production. Moreover, an excessive spray of chemical insecticides leads to development of insecticide resistance as well adverse effects on environment and humans. The brassica leaf beetle, Phaedon brassicae, is a coleopteran pest. Both larval and adult stages feed cabbage. This study aimed to develop an effective microbial biopesticide against P. brassicae by adding immunosuppressive agent to Bacillus thurigiensis (Bt). To determine an optimal immunosuppressive agent, two bacterial species of Photorhabdus temperata subsp. temperata (Ptt) and Xenorhabdus nematophila were compared in their insecticidal activity against P. brassicae, and Ptt was selected. Among four subspecies of Bt, B. thuringiensis subsp. tenebrionis (Btt) was selected. Ptt bacterial culture broth possessed immunosuppressive agent(s) because the bacterial culture broth significantly increased other bacterial growth in P. brassicae hemolymph. When the Ptt broth was added to Btt, it significantly increased the insecticidal activity of Btt. Bt-Plus was prepared by mixing Btt and Ptt bacterial culture and sprayed the cabbage infested by P. brassicae. The Bt-Plus was much more effective than Btt treatment. This study reports a novel Bt insecticide to control P. brassicae.

Inhibitory effects of a recombinant viral cystatin protein on cysteine protease catalytic activity and development of Plutella xylostella

Yeongtae Kim,Seonghyun Eom,Yonggyun Kim 한국응용곤충학회 2014 한국응용곤충학회 학술대회논문집 Vol.2014 No.04

Cystatins (CSTs) are reversible and competitive inhibitors of C1A cysteine proteases, corresponding to papain-like cathepsins in plants and animals. A viral CST (CpBV-CST1) was identified from a polydnavirus, Cotesia plutellae bracovirus. Our previous study indicated that overexpression of CpBV-CST1 interfered with immune response and development of Plutella xylostella larvae. This study produced a recombinant CpBV-CST1 protein (rCpBV-CST1) using bacterial expression system to analyze its inhibitory activity against cysteine protease and physiological role in the parasitism of an endoparsitoid wasp, Cotesia plutellae. The open reading frame (ORF) of CpBV-CST1 encodes a polypeptide of 138 amino acids (15 kDa). rCpBV-cystatin protein in BL21 STAR (DE3) competent cells containing a recombinant pGEX4T-3:CpBV-CST1 was overexpressed by 0.5 mM IPTG for 4 h. In biological activity assay, partially purified GST-fused rCpBV-CST1 showed inhibitory activity against papain. It also inhibited larval development of P. xylostella in a dose-dependent manner. These results suggest that CpBV-CST1 plays a role in retardation of larval development of P. xylostella during parasitism.

Heat Tolerance of the Indian Meal Moth, Plodia interpunctella

Minhyun Kim,Seunghee Lee,Yonggyun Kim 한국응용곤충학회 2015 한국응용곤충학회 학술대회논문집 Vol.2015 No.10

Heat treatment has been widely used to control some stored insect pests. The Indian meal moth, Plodia interpunctella, gives massive economic loss to most stored grains. Heat tolerance of P. interpunctella was assessed in most developmental stages in this study. Heat treatment at 44oC for 1 h was lethal to P. interpunctella. Compared to other developmental stages, late larval instar larvae were more tolerant to the heat treatment. Some of the fifth instar larvae could survive under 44oC for 80 min, but completely died at exposure to 45oC for 80 min. However, the survival rates of the larvae significantly increased by pre-exposure to sublethal temperature at 37oC. The rapid induction of heat tolerance was accompanied with increases in gene expressions of two heat shock proteins, Hsp70 and Hsp90, but not in that of Hsp25. Interestingly, hemolymph trehalose levels also increased from 39.2 mM to 51.3 mM by pre-exposure to 37oC for 30 min. These results suggest that P. interpunctella induces a rapid heat tolerance by up-regulation of heat shock protein levels and hemolymph trehalose levels.

Oral Toxicity of Benzylideneacetone against the Beet Armyworm, Spodopteraexigua, by Inhibiting Digeotive Phospholipase A2

Jaehyun Kim,Yonggyun Kim 한국응용곤충학회 2009 한국응용곤충학회 학술대회논문집 Vol.2009 No.05

A monoterpenoid, benzylideneacetone (BZA), is synthesized by an entomopathogenic bacterium, Xenorhabdus nematophila K1, and known to suppress insect immune responses by inhibiting phospholipase A2(PLA2). This was designed to test its effect of insect digestion by oral administration. The beet armyworm, Spodoptera exigua, was tested by treating its artificial diet with different doses of BZA. The second instar larval were treated with the diets and monitored in their pupation, pupal weight, and adult emergence. BZA gave significant adverse effects on the larval development and subsequent adult metamorphosis. Digestive lumen of the fifth instar larval of S. exigua possessed activity, which was significant inhibited by BZA. These results support that BZA can be developed as a novel feeding deterrent.