Identification of Carboxylesterase Genes and Function of Three Inducible α-Esterase Genes Involved in Insecticidal Activity of α-Solanine in .

Carboxylesterases (CarEs) play an important role in the detoxification of exogenous toxic compounds in insects. However, the effect of CarEs (PoCarEs) on the insecticidal activity of α-solanine, a potato-derived secondary metabolite, remains unclear. In this study, we identified 96 PoCarEs.

A testis-specific heat shock protein gene plays a critical role in male fertility in the fall armyworm.

Heat shock proteins (Hsps) are critical for stress responses and multiple physiological processes, yet their function in insect reproduction remains underexplored. In this study, we identified 36 Hsp genes in the fall armyworm (Spodoptera frugiperda), of which LOC118269601 (designated as SfHsp68A) exhibited robust testis-specific expression, peaking during pupal testis development. CRISPR/Cas9-mediated knockout of SfHsp68A resulted in recessive male sterility, significantly reduced testis size, sperm counts, and egg hatch rates.

Histone and N-terminal acetyltransferases play important roles in female reproduction and embryogenesis of the red flour beetle Tribolium castaneum.

Histone acetyltransferases (HATs) catalyse the addition of acetyl groups to histones and other proteins. In contrast, histone deacetylases remove acetyl groups from core histones, and the activity of these enzymes maintains the acetylation levels of these proteins. Histone acetylation levels influence chromatin accessibility and gene expression and regulate many biological processes, including development and reproduction.

Environmental factors affecting RNAi efficacy: Temperature but not plant cultivar influences Colorado potato beetle's response to insecticidal dsRNA.

Environmental RNAi (eRNAi) is a recent innovation in insect pest control, and comprehensive risk assessment is needed to ensure the environmental safety and longevity of this technology. As eRNAi relies on the insect's cellular machinery for its mode of action, environmentally mediated plasticity in the activity of cellular processes required for RNAi could influence efficacy and the development of resistance. Here, we investigated the extent to which plant cultivar and temperature influence the efficacy of insecticidal double-stranded RNA (dsRNA) targeting actin in larvae of the Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae).

β2-tubulin regulates the development and migration of eupyrene sperm in Spodoptera frugiperda.

Spermatogenesis is the basis of sexual reproduction and is essential for the propagation of insect populations. Understanding the process of spermatogenesis and identifying key genes involved in sperm function can aid in developing pest genetic control methods. The testis-specific gene β2-tubulin (B2t) is crucial for spermatogenesis in insects possessing monomorphic spermatids.

Role of histone methylation in insect development: KMT5A regulates ecdysteroid biosynthesis during metamorphosis of Tribolium castaneum.

Methylation levels of core histones play important roles in the regulation of gene expression and impact animal development. However, the methyltransferases and demethylases that determine histone methylation levels remain largely unexplored in insects. Most of our current understanding of histone methylation comes from mammalian studies.

Identification of Histone and N-Terminal Acetyltransferases Required for Reproduction and Embryonic Development of Yellow Fever Mosquito, Aedes aegypti.

Histone acetylation levels maintained by histone acetyltransferases (HATs) and histone deacetylases play important roles in maintaining local chromatin accessibility and expression of genes that regulate many biological processes, including development and reproduction. N-terminal acetylation of proteins catalyzed by N-terminal acetyltransferases (NATs) also regulates gene expression. We identified 25 HATs/NATs genes in the yellow fever mosquito, Aedes aegypti, and investigated their function in female reproduction using RNA interference (RNAi).

N-alpha-acetyltransferase 40 modulates ecdysteroid action through chromatin accessibility changes near the promoters of 20-hydroxyecdysone response genes in Tribolium Castaneum TcA cells.

Changes in chromatin accessibility leading to altered gene expression play critical roles in cellular response to environmental signals. The function of N-alpha-acetyltransferase 40 (NAA40) in modulating chromatin accessibility and transcriptional regulation of 20-hydroxyecdysone (20E) response in Tribolium castaneum (TcA) cells was investigated. RNA interference (RNAi) was used to knockdown NAA40, and ATAC and RNA sequencing were used to examine changes in chromatin accessibility and gene expression in TcA cells exposed to 20E.

Knockout of a testis-specific gene cluster impairs male fertility in the fall armyworm, Spodoptera frugiperda.

Background: The function of some testis-specific genes (TSGs) in model insects have been studied, but their function in non-model insects remains largely unexplored. In the present study, we identified several TSGs in the fall armyworm (FAW), a significant agricultural pest, through comparative transcriptomic analysis. A testis-specific gene cluster (TSGC) comprising multiple functional genes and long non-coding RNAs was found.

Knockout BR-C induces premature expression of E93 thus triggering adult differentiation under larval morphology.

Background: Holometabolan pupal-specifier broad-complex (BR-C) and adult specifier ecdysone-induced protein 93F (E93) are essential for metamorphosis; however, their interaction and effects on programmed cell death and cell differentiation during pupation remain unclear.

Results: Here, multiple single-guide RNA (sgRNA)-mediated mosaic knockout of BR-C induced a deformed larva/pupa intermediate phenotype in Spodoptera frugiperda. Quantitative real-time polymerase chain reaction (qPCR) analysis showed that the adult specifier E93 was prematurely expressed in the BR-C mutants during the penultimate and last instar larval stages.

Chronologically inappropriate morphogenesis () is required for maintenance of larval stages of fall armyworm.

Broad complex (Br-C) and eip93F (E93) transcription factors promote insect metamorphosis from larva to pupa and from pupa to adult, respectively. Recently, chronologically inappropriate morphogenesis (Chinmo) has been proposed as a larval specifier in r. However, whether Chinmo is required for larval maintenance in lepidopteran insects, the underlying mechanisms involved in maintaining the larval stage, and its interactions with the JH signaling pathway are not well understood.

RNA modifications in insects.

More than 100 RNA chemical modifications to cellular RNA have been identified. -methyladenosine (mA) is the most prevalent modification of mRNA. RNA modifications have recently attracted significant attention due to their critical role in regulating mRNA processing and metabolism.

Deciphering cellular heterogeneity in Spodoptera frugiperda midgut cell line through single cell RNA sequencing.

Using the 10x Genomics Chromium single-cell RNA sequencing (scRNA-seq) platform, we discovered unexpected heterogeneity in an established cell line developed from the midgut of the Fall armyworm, Spodoptera frugiperda, a major global pest. We analyzed the sequences of 18,794 cells and identified ten unique cellular clusters, including stem cells, enteroblasts, enterocytes and enteroendocrine cells, characterized by the expression of specific marker genes. Additionally, these studies addressed an important knowledge gap by investigating the expression of genes coding for respiratory and midgut membrane insecticide targets classified by the Insecticide Resistance Action Committee.

Recent advances in understanding of the mechanisms of RNA interference in insects.

We highlight the recent 5 years of research that contributed to our understanding of the mechanisms of RNA interference (RNAi) in insects. Since its first discovery, RNAi has contributed enormously as a reverse genetic tool for functional genomic studies. RNAi is also being used in therapeutics, as well as agricultural crop and livestock production and protection.

StaufenC facilitates utilization of the ERAD pathway to transport dsRNA through the endoplasmic reticulum to the cytosol.

RNA interference (RNAi) is more efficient in coleopteran insects than other insects. StaufenC (StauC), a coleopteran-specific double-stranded RNA (dsRNA)-binding protein, is required for efficient RNAi in coleopterans. We investigated the function of StauC in the intracellular transport of dsRNA into the cytosol, where dsRNA is digested by Dicer enzymes and recruited by Argonauts to RNA-induced silencing complexes.

The mechanoreceptor Piezo is required for spermatogenesis in Bombyx mori.

Background: The animal sperm shows high diversity in morphology, components, and motility. In the lepidopteran model insect, the silkworm Bombyx mori, two types of sperm, including nucleate fertile eupyrene sperm and anucleate unfertile apyrene sperm, are generated. Apyrene sperm assists fertilization by facilitating the migration of eupyrene spermatozoa from the bursa copulatrix to the spermatheca.

Proactive resistance management for sustaining the efficacy of RNA interference for pest control.

Biopesticides based on RNA interference (RNAi) took a major step forward with the first registration of a sprayable RNAi product, which targets the world's most damaging potato pest. Proactive resistance management is needed to delay the evolution of resistance by pests and sustain the efficacy of RNAi biopesticides.

Cyp6g2 is the major P450 epoxidase responsible for juvenile hormone biosynthesis in Drosophila melanogaster.

Background: Juvenile hormones (JH) play crucial role in regulating development and reproduction in insects. The most common form of JH is JH III, derived from MF through epoxidation by CYP15 enzymes. However, in the higher dipterans, such as the fruitfly, Drosophila melanogaster, a bis-epoxide form of JHB3, accounted most of the JH detected.

N(alpha)-acetyltransferase 40-mediated histone acetylation plays an important role in ecdysone regulation of metamorphosis in the red flour beetle, Tribolium castaneum.

Histone acetylation, a crucial epigenetic modification, is governed by histone acetyltransferases (HATs), that regulate many biological processes. Functions of HATs in insects are not well understood. We identified 27 HATs and determined their functions using RNA interference (RNAi) in the model insect, Tribolium castaneum.

CRISPR-Cas9 mediated dsRNase knockout improves RNAi efficiency in the fall armyworm.

Lepidopteran insects are refractory to RNA interference (RNAi) response, especially to orally delivered double-stranded RNA (dsRNA). High nuclease activity in the midgut lumen is proposed as one of the major reasons for RNAi insensitivity. We identified three dsRNase genes highly expressed in the midgut of fall armyworm (FAW), Spodoptera frugiperda.

Transcript Level and Sequence Matching Are Key Determinants of Off-Target Effects in RNAi.

Double-stranded RNA (dsRNA) pesticides, those based on RNA interference (RNAi) technology utilizing dsRNA, have shown potential for pest control. However, the off-target effects of dsRNA pose limitations to the widespread application of RNAi and raise concerns regarding potential side effects on other beneficial organisms. The precise impact and underlying factors of these off-target effects are still not well understood.