Metarhizium은 대표적인 곤충병원성 진균 중 하나로, 종에 따라 매우 다양한 곤충에게 병원성을 일으키는 폭 넓은 기주범위를 형성한다. 이들이 주로 생성하는 것으로 알려진 destruxins (DTXs)이라는 2차 대사산물은 살충 활성 뿐만 아니라 항바이러스, 항증식, 항암 등 다양한 분야에서 효능이 연구되고 있어, 해당 물질에 대한 관심이 집중되고 있다. 살충 물질로서의 DTXs는 여러 곤충에 있어 병원성을 나타내는 것이 확인되었으나, 해충 으로서 전 세계적으로 심각한 경제적 피해를 일으킴과 동시에, 화학 살충제 저항성 문제가 야기되고 있는 목화진 딧물에 대해서는 아직 DTXs의 역할이 연구되지 않고 있는 실정이다. 본 연구에서는 목화진딧물에 대해 곤충병원 성 진균 Metarhizium spp.의 병원성 발현에 DTXs가 미치는 역할을 간접적으로 확인하기 위해, qPCR을 활용하여 진균 처리 후 목화진딧물 사망 시간과 관련하여 충체 내 DTX 합성효소의 발현을 비교 분석하였다.

The fall armyworm, Spodoptera frugiperda, has developed extremely high levels of resistance to chlorantraniliprole and other classes of insecticides in the field. As microRNAs (miRNAs) play important roles in various biological processes through gene regulation. we examined the miRNA profile of S. frugiperda in response to Chlorantraniliprole, Indoxacarb and Thiamethoxam. Transcriptome analysis showed significant changes in the abundance of some miRNAs after treatment of S. frugiperda larvae with LC20 concentrations of three insecticides. A total of 197 miRNAs were systematically identified from S. frugiperda, and 16, 9, 2 miRNAs were differentially expressed after treatments of three insecticides. Importantly, three miRNAs were significantly downregulated and three were upregulated by RT-qPCR after treatment the LC50 of three insecticides with S. frugiperda larvae. Microinjection of agomirs of these six miRNAs into S. frugiperda larvae resulted in significant changes in mortality rates when exposed to three insecticides. Additionally, we also screened potential target genes for some of differentially expressed miRNAs, which may play important roles in insecticide resistance development. These findings provide valuable insights into the molecular mechanisms of insecticide resistance and underscore the potential of miRNAs as targets for the development of novel pest control strategies in S. frugiperda.

A new fumigant, carbonyl sulfide (COS), has potential for use as a replacement for methyl bromide, yet its mechanism of toxicity to insects remains poorly understood. In this study, transcriptome analysis was performed on Tribolium castaneum malpighian tubules and fat bodies, which are known to play an essential role in energy storage and utilization in insect species. In total, upon exposure to COS, 3,034 and 2,973 genes were differentially expressed in the T. castaneum malpighian tubules and fat body, respectively. These differentially expressed genes comprise a significant number of detoxification-related genes, including 105 P450s, 18 glutathione S-transferases (GSTs), 82 ABC transporters, 25 UDP-glucosyltransferases and 42 carboxylesterases and mitochondrial–related genes, including 9 complex Ⅰ genes, 2 complex Ⅱ genes, 1 complex Ⅲ gene, 9 complex IV genes, 8 complex V genes from both malpighian tubules and fat body tissues. Moreover, KEGG analysis demonstrated that the upregulated genes were enriched in xenobiotic metabolism by ABC transporters and drug metabolism by other enzymes. We also investigated the role of carbonic anhydrases (CAs) in toxicity of COS using dsRNA treatment in T. castaneum. These results show that CA genes have a key role in toxicity of the COS. Furthermore, the results of transcriptomic analysis provide new insights into the insecticidal mechanism of COS fumigation against T. castaneum and eventually contribute to the management of this important stored grain pests.

Although ethylformate and phosphine fumigants are widely used for pest quarantine, studies related to their mechanism of action and metabolic physiological changes in Drosophila models are still unclear. In this study, we investigated how key metabolites altered by fumigants and cold treatment are associated with and affect insect physiology by comparative metabolome analysis. Fumigant treatment significantly altered cytochrome P450 and glutathione metabolites involved in the detoxification mechanism and showed lower expression of PGF2α involved in the immune response compared to the control. Additionally, most of the metabolites functioned in metabolic pathways related to the biosynthesis of amino acids, nucleotides and cofactors.

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.

Colon cancer is one of the most common malignant tumors, but there are still a few validated biomarkers of colon cancer. Exosome-mediated microRNAs (miRNAs) have been recognized as potential biomarkers in cancers, and miRNAs can regulate a variety of genes. Recently, Fusobacterium nucleatum was discovered in the tissues of human colon cancer patients. Its role in colon cancer was highlighted. F. nucleatum may contribute to the progression of colon cancer through the mechanism of exosome-mediated miRNAs transfer. However, the exosomal miRNAs regulation mechanism by F. nucleatum in colon cancer is not well known. Thus, we performed next-generation sequencing to investigate the overall pattern of exosomal miRNAs expression in the colon cancer cell culture supernatant. We have confirmed the alterations of various exosomal miRNAs. In addition, to investigate the function of exosomal miRNAs, a Kyoto Encyclopedia of Genes and Genomes analysis was performed on the target genes of changed miRNAs. Potential target genes were associated with a variety of signaling pathways, and one of these pathways was related to colorectal cancer. These findings suggested that F. nucleatum can alter exosomal miRNAs released from colorectal cancer cells. Furthermore, exosomal miRNAs altered by F. nucleatum could be potential biomarkers for the diagnosis and therapy of colon cancer.

The aim of this study was to compare the two in vitro culture systems callus and adventitious root by investigating the biomass and phenolic compounds in calli and adventitious roots induced from four different explants (leaf, root, petal, and ovary) in Camellia japonica. The biomass of calli and adventitious roots was examined after 4 and 8 weeks of cultivation, respectively, and 22 phenolic compounds were analyzed using high-performance liquid chromatography (HPLC). The biomass of the ovary-derived calli (2.0 g･mass-1) was 1.5-fold that of the leaf-derived calli. The dry weight (DW) was highest in ovary-derived calli; however, the highest dry matter content was obtained from leaf-derived calli. Differences in the investigated characteristics depended on the callus origin. In adventitious roots, the highest biomass was achieved in the leaf-derived adventitious root system; its fresh weight was 2.3-fold (89 mg･ea-1) higher, and its DW was 1.8-fold (16 mg･ea-1) higher than those of ovary-derived adventitious root system. Active cell division was detected in petal-derived lines in both the calli and adventitious roots. Results of the HPLC analysis revealed that the total content of 22 phenolic compounds was highest in ovary-derived calli and ovary-derived adventitious roots. Our experiments confirmed that the calli and adventitious roots of C japonica have different cytological characteristics and bioactive compounds depending on the explant origin. In addition, callus culture was a more suitable system than adventitious root for producing phenolic compounds when the duration of the culture period and biomass were considered.