To identify viruses and compare their abundance levels in the venom glands of hymenopteran species, we conducted venom gland-specific transcriptome assemblies and analyses of 22 Aculeate bees and wasps and identified the RNA genomes of picornaviruses. Additionally, we investigated the expression patterns of viruses in the venom glands over time following capture. Honeybee-infecting viruses, including black queen cell virus (BQCV), deformed wing virus (DWV), and Israeli acute paralysis virus (IAPV), were highly expressed in the venom glands of Apis mellifera and social wasps. This finding suggests that the venoms of bees and wasps likely contain these viruses, which can be transmitted horizontally between species through their stinger usage. A. mellifera exhibited an increasing pattern of abundance levels for BQCV, DWV, IAPV, and Triatovirus, while the social wasp Vespa crabro showed increasing abundance levels of IAPV and Triatovirus over different capture periods. This suggests that the venom glands of honeybees and wasps may provide suitable conditions for active viral replication and may be an organ for virus accumulation and transmission. Some viral sequences clearly reflected the phylogeny of Aculeate species, implying host-specific virus evolution. On the other hand, other viruses exhibited unique evolutionary patterns of phylogeny, possibly caused by specific ecological interactions. Our study provides insights into the composition and evolutionary properties of viral genes in the venom glands of certain Aculeate bees and wasps, as well as the potential horizontal transmission of these viruses among bee and wasp species.

Acetylcholinesterase (AChE) is a key enzyme that terminates impulse transmission by rapidly hydrolyzing the neurotransmitter acetylcholine at cholinergic synapses. Previous studies have discovered a transiently opening channel referred to as the “back door” in Torpedo californica AChE. Previously, we observed that substituting the Tyr391 residue with a Phe residue significantly decreased the catalytic efficiency of recombinant Apis mellifera AChE1 (AmAChE1), while the reverse substitution restored it. Interestingly, substitution of the Tyr391 residue with a Phe residue in AmAChE1 disrupted the formation of the backdoor, while the reverse substitution restored it. This finding suggests that the Tyr-to-Phe substitution impairs backdoor formation, thereby leading to a significant reduction in the catalytic activity of AmAChE1. This serves as one of the driving forces for the functional transition from AmAChE1 to AmAChE2. In this experiment, we also confirmed the gradual restoration and increase in AChE activity by substituting Phe391 in AmAChE1 with Ser, Trp, Thr, Ile, Asn, and Tyr residues through kinetic assay and molecular dynamics simulation.

Bemisia tabaci Gennadius, one of the most invasive insect pests, has spread quickly nationwide since it was introduced to South Korea in 2008. The use of insecticides is the main management strategy for this pest, but the control efficiency has been decreased due to insecticide resistance. We collected 12 local B. tabaci populations to investigate the regional differences in efficiency and observed the mortality from 14 commercial insecticides applied at recommended concentrations (RC) and dilutions (0.1 RC and 0.01 RC) using the leaf dipping bioassay. Except for etofenprox (46-64%), thiamethoxam (37-60%), pyriproxyfen (21-61%), and pyridaben (61-65%), the other insecticides showed excellent insecticidal efficacy of 70% to 100% at their RC. In particular, flupyradifurone, emamectin benzoate, and cyantraniliprole showed high insecticidal efficacy of over 90% in all of the tested populations. Some insecticides that rapidly decreased in activity (less than 30%) at diluted concentrations or showed high resistance levels in nearby regions were classified for cautious use due to the possibility or potential to develop resistance. The results provide selected insecticides for B. tabaci control by region and could contribute to reducing insecticide abuse and increasing insecticidal efficiency in farming fields.

2022년 국내 노지 마늘, 대파, 양파, 부추 작물재배지에서 채집한 파총채벌레 지역집단들에 대하여 살충제 저항성을 조사하였다. 제조사 추천약량에서의 살충력은 acrinathrin SC를 제외한 6종 약제들이 안성 등 8개 집단 에서 모두 90%이상을 보였으며, Spinetoram SC와 fluxametamide EC는 추천농도의 100배 희석농도에서도 전 지역 집단에 걸쳐 높은 살충력을 보여주었다. 미리 저항성 진단농도로 코팅한 바이알을 이용한 지역집단의 저항성 검정을 실시한 결과, emamectin benzoate의 저항성이 신안 등 9개 지역집단에서 매우 높았으며, chrantraniliprole은 부산 등 4개 , spinetoram은 의성 등 3개, actamiprid와 chlorfenapyr는 각각 1개의 지역집단에서 저항성이 높게 발달 하고 있는 것을 확인할 수 있었으며, 지역별로는 주요 대파 및 양파 재배지인 안성, 서산, 진도, 신안 지역의 저항성 이 모든 약제에 대하여 전반적으로 높게 나타났다.

The onion thrips, Thrips tabaci (Thysanoptera: Thripidae), is a worldwide pest that causes serious damage to Allium crop species and acts as a vector for iris yellow spot virus (IYSV). In a previous study, we established an emamectin benzoate (EB) resistant strain (EB-R) with a 490-fold higher resistance ratio than the susceptible strain (SUS). The EB-R exhibited significantly increased transcript levels of glycine receptor alpha, glutamate-gated chloride channel (GluCl) b, and cytochrome P450 (CYP450) 6EB2 compared to SUS. To identify EB resistance-related genes that are differentially expressed genes between SUS and EB-R, we established an isogenic backcrossing strain and conducted transcriptome analysis after the 4th cycle of isogenic backcrossing. Among the 85 up-regulated genes in the transcriptome data, six cuticular protein genes showed up-regulation. Additionally, CYP450 4g15, which catalyzes the synthesis of cuticular hydrocarbons, exhibited a 6 log2-fold higher expression level in EB-R compared to SUS. Therefore, the elevated expression of genes associated with cuticle protein modification may be significantly is involved in the development of EB resistance.

To identify and compare the venom components and expression patterns of some bees/wasps, venom gland-specific transcriptome analyses were conducted for 14 Aculeate bees/wasps. Most of the allergens and pain-producing factors showed extremely high expression levels in social wasps, implying that social wasps have evolved to use venom to defend the colony against intruders. Acid phosphatase and tachykinin, which are known as allergens and neurotoxic peptides, were found with high frequencies in the venom glands of solitary wasps. This suggests that solitary wasps might use their venom for catching and preserving prey. In the venom glands of bumblebees, little or no transcripts of major allergens or pain producing factors were identified, implying that bumblebees venoms are relatively less toxic than those of social or solitary wasps. Taken together, the differential expression patterns of venom genes in some Aculeate bees/wasps implies that bees/wasps have unique groups of highly expressed venom components, which appear to have evolved in response to both ecological and behavioral influences.

In order to identify the specific antigens for pine wood nematode (PWN), we confirmed that one of the genes commonly found in the transcriptome, proteome and secretory proteins of PWN belonged to the Aldose Reductase (AR) family protein. 36.5 kDa PWN-AR1 was expressed and purified using Baculovirus Expression System. Total 1,546 hybridoma fusion library was generated and screened for specificity to PWN-AR1 by Enzyme Linked Immunosorbent assay (ELISA). Nine clones showed strong immunoreactivity to PWN-AR1 were limited-diluted. Total 864 limited-diluted clones were further screened using PWN-AR1 by ELISA and 34 monoclonal antibody (Mab) clones were selected. 34 Mab clones were further screened using PWN extracts and a standard PWN-infected pine tree extract by ELISA. Finally nine clones were selected and their immunoreactivities to 4 different nematodes were examined by ELISA. Seven clones pecifically recognized PWN while two clones recognized 4 nematodes. Our data suggested that PWN-AR1 is a PWN secretory enzyme while PWN is invading pine trees, Thus, PWN-AR1-Mabs could be used to develop diagnosis tools for PWN and its infected pine trees. (This work was supported by National Institute of Forest Science)

소나무재선충(Pine wood nematode, PWN)은 아시아와 유럽의 소나무류들에 침입하여 고사시키는 심각해 병원성 선충이다. 가장 완벽한 방제 방법은 감염목을 소각/분쇄의 방법으로 PWN 감염목을 제거하는 것이다. 현재 PWN의 다른 종과 차이를 가지는 유전자서열을 이용한 진단 방법이 다양하게 개발되어져서 실험실에서의 종 판명은 가능한 실정이다. 하지만, 대부분의 분자진단방법은 소나무 목편에서부터의 시료 추출, 그리고 분자진단 시약과 혼합하고, PCR을 이용하여 증폭을 진행 한 후, 결과를 확인하는 과정이 필요하다. 그러므로, 분자진단법을 현장에 적용하기 위해서는 향 후 많은 노력이 필요하다. 이에 반하여 항원/항체 반응을 이용한 진단 방법의 경우는 항원 추출 후, 일정량을 신속진단키트에 떨어 뜨려서 반응을 확인하는 과정을 거치므로, 전문적인 지식이나 기술이 필요하지 않다. 하지만, PWN과 PWN 감염목에 특이적인 항원이 밝혀지지 않은 상황이다. 최근에 우리는 PWN단백질 중에서 분비되는 Aspartic peptidase 1 (ASP1)을 항원으로 선정을 하고, 전장단백질을 Baculovirus Expression System으로 발현을 하였다. PWN-ASP1을 항원으로 단클론항체를 분비하는 세포 주를 확립하였다. 이러한 단클론항체는 향후, PWN의 소나무 침입에 관한 연구와 신속진단키트의 개발에 활용될 수 있을 것이다. (본 연구는 국립산림과학원의 연구비 지원으로 진행되었음)