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As an important global food crop, rice is damaged by a variety of piercing–sucking pests. Identifying a broad-spectrum promoter induced by the physical signal of sucking pests and applying it to transgenic breeding to mitigate the damage caused by different sucking pests will significantly improve the efficiency of our breeding. This study compared the transcriptome changes in two rice varieties under needle-wounding stress to investigate their differential responses to mechanical damage. The results showed that the insect-susceptible variety TN1 exhibited more differentially expressed genes (DEGs) and greater changes in expression levels after needle treatment, indicating a more active internal gene regulatory network. GO and KEGG enrichment analysis further revealed that TN1 not only exhibited changes in genes related to the extracellular environment, but also mobilized more genes associated with stress response and defense. By screening the differentially expressed genes, we identified two promoters (P1 and P2) with inducible expression characteristics in both the resistant and susceptible rice varieties. These promoters were able to effectively drive the expression of the insect resistance gene OsLecRK1* and enhance the resistance of transgenic plants against the brown planthopper. This study provides promoter resources for the development of insect-resistant transgenic crops. [ABSTRACT FROM AUTHOR]

Insects produce silk to form cocoons, nests, and webs, which are important for their survival and reproduction. However, little is known about the molecular mechanism of silk protein synthesis at the translation level. The solute carrier family 7 (SLC7) genes are involved in activating the target of rapamycin complex 1 (TORC1) signaling pathway and protein translation process, but the physiological roles of SLC7 genes in silk‐producing insects have not been reported. Here, we found that amino acid signaling regulates silk protein synthesis and larval development via the L‐type amino acid transporter 1 (LAT1; also known as SLC7A5) in Bombyx mori. A total of 12 SLC7 homologs were identified in the silkworm genome, among which BmSLC7A5 was found to be a silk gland‐enriched gene and may be involved in leucine transport. Bioinformatics analysis indicated that SLC7A5 displays high homology and a close phylogenetic relationship in silk‐producing insects. Subsequently, we found that leucine treatment significantly increased silk protein synthesis by improving the transcription and protein levels of silk genes. Furthermore, systemic and silk gland‐specific knockout of BmSLC7A5 led to decreased silk protein synthesis by inhibiting TORC1 signaling, and somatic mutation also resulted in arrested development from the 5th instar to the early pupal stage. Altogether, our study reveals that BmSLC7A5 is involved in regulating silk protein synthesis and larval development by affecting the TORC1 signaling pathway, which provides a new strategy and target for improving silk yield. [ABSTRACT FROM AUTHOR]

In northwest China, changes in cultivation patterns and the scarcity of preferred hosts have forced Helicoverpa armigera to feed on the marginal host walnut (Juglans regia). However, the mechanisms allowing this adaptation remain poorly understood. Here, we investigated the behavioral, physiological, and molecular mechanisms underlying the local adaptation of this pest to walnut fruits. The green husk and shell generally contained higher levels of phytochemicals than the kernel. Bioassays revealed that the phytochemical-rich green husk and shell were less preferred, reduced larval fitness and growth, and elevated the activity of detoxification enzymes compared to the nutrient-rich kernel, which were further supported by a larger number of upregulated detoxification genes in insects fed green husks or shells based on transcriptome sequencing. Together, these data suggest that P450 genes (LOC110371778) may be crucial to H. armigera adaptation to the phytochemicals of walnuts. Our findings provide significant insight into the adaptation of H. armigera to walnut, an alternative host of lower quality. Meanwhile, our study provides a theoretical basis for managing resistance to H. armigera larvae in walnut trees and is instrumental in developing comprehensive integrated pest management strategies for this pest in walnut orchards and other agricultural systems. [ABSTRACT FROM AUTHOR]

Phytoplasmas can negatively or positively alter vector host fitness. " Candidatus Phytoplasma pyri ," is the causal agent of pear decline in commercial pear (Pyrus communis L.; Rosales: Rosaceae) and peach yellow leafroll in peach [ Prunus persica (L.); Rosaceae]. This plant pathogen is transmitted by several species of pear psyllids (Cacopsylla spp. Hemiptera: Psyllidae). We sought to explore the relationship between the pear decline phytoplasma and its US vector, Cacopsylla pyricola (Förster), at the molecular genetic level through transcriptomic analysis using RNA-sequencing methodology. We also focused on phytoplasma and insect effectors, which are secreted proteins that can modulate interactions within a pathosystem. In this study, we identified 30 differentially expressed genes, 14 candidate insect effector genes, and 8 Ca. Phytoplasma pyri candidate effectors. Two strains of Ca. Phytoplasma pyri were identified based on immunodominant membrane protein sequence analysis from C. pyricola collected in the Pacific Northwest agricultural region. Here, we present a first genetic look at the pear decline pathosystem and report gene candidates for further exploration of infection mechanisms and potential tools for integrated pest management. [ABSTRACT FROM AUTHOR]

Maize lethal necrosis is attributed to the accumulation of maize chlorotic mottle virus (MCMV), an invasive virus transmitted by insect vectors. The western flower thrips (WFT) can shift host to maize, thus promoting the spread of MCMV. However, our understanding of the characteristics and interactions involved in the transmission of MCMV is still limited. This study finds that non-viruliferous WFTs showed a 57.56% higher preference for MCMV-infected maize plants compared to healthy maize plants, while viruliferous WFTs showed a 53.70% higher preference for healthy maize plants compared to MCMV-infected maize plants. We also show for the first time that both adults and larvae of WFT could successfully acquire MCMV after 1 min of acquisition access period (AAP), and after 48 h of AAP, WFT could transmit MCMV in an inoculation access period of 1 h without a latent period. Both adults and larvae of WFT can transmit MCMV for up to 2 days. Furthermore, the decreasing number of viruliferous WFTs and transmission rates as time progressed, together with the transcriptomic evidence, collectively suggest that WFTs transmit MCMV in a semi-persistent method, a mode of transmission requiring minutes to several hours for acquisition access and having a retention time of several hours to a few days. Additionally, β-myrcene can attract WFTs significantly and is detected in Nicotiana benthamiana plants transiently expressing MCMV CP (coat protein), which is consistent with results in MCMV-infected maize plants through the metabolomic profiling and the preference analyses of WFT. Therefore, this study demonstrates the indirect interaction between MCMV and WFT by inducing maize to synthesize β-myrcene to attract insect vectors. The exploration of specific interactions between MCMV and WFT could help to expand the mechanism studies of virus--vector--host plant interaction and put forward a new insight for the combined control of MCMV and WFT through the manipulation of plant volatiles and key insect genes. [ABSTRACT FROM AUTHOR]

Anoplophora glabripennis is one of the most devastating wood-boring beetles that attacks poplars. However, one poplar species, Populus deltoides, has strong resistance to Anoplophora glabripennis infestation, the underlying defense mechanisms against Anoplophora glabripennis are poorly understood. Secondary metabolites play a crucial role in plants to combat biological stress. Here, based on transcriptome and metabolome, we demonstrated that the mechanisms for responses to mechanical damage and insect infestation were different. The degree of reactions to adult groove production, larval incubation, and larval frass production was not identical. In addition, the potential genes with insect resistance activity were identified. Predominant differentially expressed genes (DEGs) found in the phloem of Populus deltoides include anthocyanidin 3-O-glucosyltransferase5 (PdUGT72E), peroxidase 73 (PdPod73), peroxidase A2 (PdPodA2) and macrophage migration inhibitory factor (PdMIF) responded to stress caused by Anoplophora glabripennis, which further resulted in activation of the plant defense system against insects via changes in regulation of metabolic pathways, such as tyrosine metabolism pathway, phenylpropanoid biosynthesis pathway and flavonoid biosynthesis pathway. Therefore, this work has laid a foundation for further unraveling the mechanisms involved in this interaction. [ABSTRACT FROM AUTHOR]

Despite major breeding efforts by various national and international agencies, yields for the ~40 million hectares of maize, the major food crop in sub‐Saharan Africa, have stagnated at <2 tons/ha/year for the past decade, one‐third the global average. Breeders have succeeded in breeding increased yield with a modicum of tolerance to some single‐weed or pathogen stresses. There has been minimal adoption of these varieties because introgressing polygenic yield and tolerance traits into locally adapted material is very challenging. Multiple traits to deal with pests (weeds, pathogens, and insects) are needed for farmer acceptance, because African fields typically encounter multiple pest constraints. Also, maize has no inherent resistance to some of these pest constraints, rendering them intractable to traditional breeding. The proposed solution is to simultaneously engineer multiple traits into one genetic locus. The dominantly inherited multi‐pest resistance trait single locus can be bred simply into locally adapted, elite high‐yielding material, and would be valuable for farmers, vastly increasing maize yields, and allowing for more than regional maize sufficiency. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Paternal genome elimination (PGE) is an intriguing but poorly understood reproductive strategy in which females are typically diploid, but males lose paternal genomes. Paternal genome heterochromatin (PGH) occurs in arthropods with germline PGE, such as the mealybug, coffee borer beetles, and booklice. Here, we present evidence that PGH initially occurs during early embryo development at around 15 h post-mating (hpm) in the cotton mealybug, Phenacoccus solenopsis Tinsley. Transcriptome analysis followed by qPCR validation indicated that six histone lysine methyltransferase (KMT) genes are predominantly expressed in adult females. We knocked down these five genes through dsRNA microinjection. We found that downregulation of two KMT genes, PsEZH2-X1 and PsEHMT1, resulted in a decrease of heterochromatin-related methylations, including H3K27me1, H3K27me3, and H3K9me3 in the ovaries, fewer PGH male embryos, and reduced male offspring. For further confirmation, we obtained two strains of transgenic tobacco highly expressing dsRNA targeting PsEZH2-X1 and PsEHMT1, respectively. Similarly, fewer PGH embryos and fewer male offspring were observed when feeding on these transgenic tobacco plants. Overall, we present evidence that PsEZH2-X1 and PsEHMT1 have essential roles in male embryo survival by regulating PGH formation in cotton mealybugs. The roles of histone lysine methyltransferases EZH2 and EHMT1 in male embryo development of cotton mealybug are investigated, with RNAi against both genes leading insects to produce fewer PGH embryos and fewer male offspring [ABSTRACT FROM AUTHOR]

Viruses, bacteria, fungus, protozoans, and different metazoan parasites and parasitoids present a constant threat to insects. Insect immunity has two components: humoral and cell mediated. Humoral immunity can be achieved by various antimicrobial proteins, namely, cecropins, sarcotoxin, defensin, attacin, etc. The cell‐mediated immunity comprises various cells having immune functions fostering nodulation, phagocytosis, microaggregation, encapsulation etc. Eicosanoids play a crucial role in insect immunity comparable to other animals. The above‐mentioned are signaling molecules derived from polyunsaturated fatty acids and they exert numerous physiological effects, namely, inflammation, immune modulation, and regulation of cellular processes. The review article elucidates various roles of eicosanoids, namely, nodulation reaction, Toll signaling pathway, nitric oxide (NO) generation, Ca2+ mobilization, production of reactive oxygen species (ROS), actin polymerization and aquaporin activation. Eicosanoids can function in immune priming in insects drawing hemocytes. An agent named Duox was also identified serving as ROS generator in insect gut. Moreover, role of Repat gene in insect immunity was also studied. However, recently the role of prostacyclin (PGI2) was found to be negative as it inhibits platelet aggregation. In this brief review, we have tried to shed light on the various functions of eicosanoids in immunity of insect those have been discovered recently. This concise study will allow to decipher eicosanoids’ function in insect immunity in a nutshell, and it will pave the way for more researches to understand the key players of insect immunity which may eventually help to develop novel vector and pest control strategies in near future. [ABSTRACT FROM AUTHOR]

Similar to the physiological importance of gut microbiomes, recent works have shown that insect ectomicrobiotas can mediate defensive colonization resistance against fungal parasites that infect via cuticle penetration. Here we show that engineering the entomopathogenic fungus Metarhizium robertsii with a potent antibacterial moricin gene from silkworms substantially enhances the ability of the fungus to kill mosquitos, locusts, and two Drosophila species. Further use of Drosophila melanogaster as an infection model, quantitative microbiome analysis reveals that engineered strains designed to suppress insect cuticular bacteria additionally disrupt gut microbiomes. An overgrowth of harmful bacteria such as the opportunistic pathogens of Providencia species is detected that can accelerate insect death. In support, quantitative analysis of antimicrobial genes in fly fat bodies and guts indicates that topical fungal infections result in the compromise of intestinal immune responses. In addition to providing an innovative strategy for improving the potency of mycoinsecticides, our data solidify the importance of both the ecto- and endo-microbiomes in maintaining insect wellbeing. Genetic engineering of Metarhizium robertsii with a silkworm antibacterial gene substantially boosts fungal potency against different insects. Both the cuticle and gut microbiomes can be disrupted to accelerate insect death after fungal infection. [ABSTRACT FROM AUTHOR]

Insects are established models for understanding host-pathogen interactions and innate immune mechanisms. The innate immune system in insects is highly efficient in recognizing and opposing pathogens that cause detrimental effects during infection. The cuticular layer which covers the superficial layer of the insect body participates in host defense and wound healing by inducing innate immune responses. Previous studies have started to address the involvement of cuticular genes in conferring resistance to insect pathogens, particularly those that infect by disrupting the insect cuticle. For example, the cuticular gene Transglutaminase (TG) in Drosophila melanogaster plays a structural role in cuticle formation and blood coagulation and also possesses immune properties against pathogenic infection. However, more information is becoming available about the immune function of other cuticular gene families in insects. In this review, we aim to highlight the recent advances in insect cuticular immunity and address the necessity of pursuing further research to fill the existing gaps in this important field of insect immunology. This information will lead to novel strategies for the efficient management of agricultural insect pests and vectors of plant and human disease. [ABSTRACT FROM AUTHOR]

Pantala flavescens (Fabricius) is the most well‐known seasonal migratory insect. This research focused on the molecular response of P. flavescens migration in summer and fall. A total of 17,810 assembled unigenes were obtained and 624 differentially expressed genes (DEGs) were identified in summer migration compared to fall migration. A number of DEGs, including cpr49Ae, itm2b, chitinase, cpr11B, laccase2, nd5, vtg2 and so on, had previously been reported to be involved in cold‐ and high‐temperature resistance. Functional enrichment analysis showed three pathways 'that antibacterial humoral response, response to bacterial, and lipid transporter activity' were significantly enriched in summer migration while that six pathways 'structural constituent of cuticle, chitin binding, mitochondrion, propanoate metabolism, citrate cycle, hypertrophic cardiomyopathy' were significantly enriched in fall migration. These results will provide a valuable baseline for further understanding of the molecular mechanisms of insect adaptation to different climate migrations. [ABSTRACT FROM AUTHOR]

Although CRISPR/Cas9 has been widely used in insect gene editing, the need for the microinjection of preblastoderm embryos can preclude the technique being used in insect species with eggs that are small, have hard shells, and/or are difficult to collect and maintain outside of their normal environment. Such is the case with Sogatella furcifera, the white‐backed planthopper (WBPH), a significant pest of Oryza sativa (rice) that oviposits inside rice stems. Egg extraction from the stem runs the risk of mechanical damage and hatching is heavily influenced by the micro‐environment of the rice stem. To bypass these issues, we targeted embryos prior to oviposition via direct parental (DIPA)‐CRISPR, in which Cas9 and single‐guide RNAs (sgRNAs) for the WBPH eye pigment gene tryptophan 2,3‐dioxygenase were injected into the hemocoel of adult females. Females at varying numbers of days posteclosion were evaluated to determine at what stage their oocyte might be most capable of taking up the gene‐editing components. An evaluation of the offspring indicated that the highest G0 gene‐edited efficacy (56.7%) occurred in females injected 2 d posteclosion, and that those mutations were heritably transmitted to the G1 generation. This study demonstrates the potential utility of DIPA‐CRISPR for future gene‐editing studies in non‐model insect species and can facilitate the development of novel pest management applications. [ABSTRACT FROM AUTHOR]

Simple Summary: The class Insecta constitutes the largest group of terrestrial animals, with more than a million described species. As in all other animals, insect genomes contain clusters of specific genes, which are essential for producing and assembling ribosomes. These clusters harbor two types of repetitive DNA, i.e., 45S and 5S ribosomal DNA (rDNA). Currently, 45S and 5S rDNA clusters have been studied in about 1000 and 100 insect species, respectively. Although the number of species with known 45S rDNA clusters constitutes less than 0.1 percent of the described members of this enormous group, certain conclusions can already be drawn. Since haploid karyotypes with single 45S and 5S rDNA clusters predominate in both basal and derived insect groups, this character state is apparently ancestral for the class Insecta in general. Nevertheless, the number, chromosomal location, and other characteristics of both 45S and 5S rDNA sites substantially vary across different species, and sometimes even within the same species. There are several main factors and mechanisms that either maintain these parameters or alter them on the short-term and/or long-term scale. Currently, clusters of 45S and 5S ribosomal DNA (rDNA) have been studied in about 1000 and 100 species of the class Insecta, respectively. Although the number of insect species with known 45S rDNA clusters (also referred to as nucleolus-organizing regions, or NORs) constitutes less than 0.1 percent of the described members of this enormous group, certain conclusions can already be drawn. Since haploid karyotypes with single 45S and 5S rDNA clusters predominate in both basal and derived insect groups, this character state is apparently ancestral for the class Insecta in general. Nevertheless, the number, chromosomal location, and other characteristics of both 45S and 5S rDNA sites substantially vary across different species, and sometimes even within the same species. There are several main factors and molecular mechanisms that either maintain these parameters or alter them on the short-term and/or long-term scale. Chromosome structure (i.e., monocentric vs. holokinetic chromosomes), excessive numbers of rRNA gene copies per cluster, interactions with transposable elements, pseudogenization, and meiotic recombination are perhaps the most important among them. [ABSTRACT FROM AUTHOR]

Cockchafers Melolontha spp. are polyphagous root pests and outbreak species of considerable economic importance to forestry in Europe. Knowledge of genetic diversity within and between cockchafer populations is largely unexplored but could lead to more effective monitoring and management strategies of these pests. In this study, we fill several gaps in the knowledge of the genetic population structure of Melolontha melolontha and Melolontha hippocastani. Using microsatellite loci and over 200 individuals per species, we examined the genetic structure of Melolontha spp. populations collected from three primary outbreak areas in central and southeastern Poland. We demonstrated that our focal species share some common genetic patterns, such as considerable genetic diversity within subpopulations (within sampling sites) with minor effects of past bottlenecks possibly masked by current population sizes. The estimates of effective population sizes, although subject to wide credibility intervals, indicated a large number of individuals contributing to further generations of the population. The migration rates exceed the threshold of one per generation required for gene flow and maintenance of population equilibrium, indicating limited impact from forest management practices on either cockchafer species. While genetic differentiation was observed in M. melolontha populations, supported by various indices (fixation index, principal coordinate analysis, assignment tests), the M. hippocastani populations were genetically similar. This disparity may hint at the potential historical divergence between these species. In this aspect, more detailed phylogeographic and population genetic studies covering a large area of the Palaearctic distributions of both species are required. Our findings constitute one of the initial efforts aimed at delineating the genetic diversity, differentiation, population structure, gene flow, and migration patterns within Melolontha spp. This exploration is especially significant for M. hippocastani , given its completely unexplored genetic population structure. [ABSTRACT FROM AUTHOR]

The oriental fruit fly, Bactrocera dorsalis (Hendel), is a significant economic and quarantine pest due to its polyphagous nature. The accurate identification of B. dorsalis is challenging at the egg, maggot, and pupal stages, due to lack of distinct morphological characters and its similarity to other fruit flies. Adult identification requires specialized taxonomist. Existing identification methods are laborious, time consuming, and expensive. Rapid and precise identification is crucial for timely management. By analyzing the variations in the mitochondrial cytochrome oxidase-1 gene sequence (Insect barcoding gene), we developed a species-specific primer (SSP), DorFP1/DorRP1, for accurate identification of B. dorsalis. The optimal annealing temperature for the SSP was determined to be 66°C, with no cross-amplification or primer-dimer formation observed. The SSP was validated with B. dorsalis specimens from various locations in northern and eastern India and tested for cross-specificity with six other economically significant fruit fly species in India. The primer specificity was further confirmed by the analysis of critical threshold (Ct) value from a qPCR assay. Sensitivity analysis showed the primer could detect template DNA concentrations as low as 1 pg/µl, though sensitivity decreased at lower concentrations. Sequencing of the SSP-amplified product revealed over >99% similarity with existing B. dorsalis sequences in the NCBI GenBank. The developed SSP reliably identifies B. dorsalis across all developmental stages and sexes. This assay is expected to significantly impact pest identification, phytosanitary measures, and eradication programs for B. dorsalis. [ABSTRACT FROM AUTHOR]

Eicosanoids mediate insect immune responses and synthesized by the catalytic activity of phospholipase A2 (PLA2). A uniquely encoded secretory PLA2 (sPLA2) is associated with immune responses of a lepidopteran insect, Spodoptera exigua. Its deletion mutant was generated using a CRISPR/Cas9 genome editing technology. Both wild and mutant lines were then immune-challenged, and the resulting transcripts were compared with their naïve transcripts by RNASeq using the Illumina-HiSeq platform. In total, 12,878 unigenes were further analyzed by differentially expressed gene tools. Over 69% of the expressed genes in S. exigua larvae are modulated in their expression levels by eicosanoids, recorded from CRISPR/Cas9 mutagenesis against an eicosanoid-synthetic gene, Se-sPLA2. Further, about 36% of the immune-associated genes are controlled by the eicosanoids in S. exigua. Indeed, the deletion mutant suffered significant immunosuppression in both cellular and humoral responses in response to bacterial challenge as well as severely reduced developmental and reproductive potentials. [ABSTRACT FROM AUTHOR]

Community-acquired pneumonia often stems from the macrolide-resistant strain of Mycoplasma pneumoniae , yet no effective vaccine exists against it. This study proposes a vaccine-immunoinformatics strategy for Mycoplasma pneumoniae and other pathogenic microbes. Specifically, dominant B and T cell epitopes of the Mycoplasma pneumoniae P30 adhesion protein were identified through immunoinformatics method. The vaccine sequence was then constructed by coupling with CTLA-4 extracellular region, a novel molecular adjuvant for antigen-presenting cells. Subsequently, the vaccine's physicochemical properties, antigenicity, and allergenicity were verified. Molecular dynamics modeling was employed to confirm interaction with TLR-2, TLR-4, B7-1, and B7-2. Finally, the vaccine underwent in silico cloning for expression. The vaccine exhibited both antigenicity and non-allergenicity. Molecular dynamics simulation, post-docking with TLR-2, TLR-4, B7-1, and B7-2, demonstrated stable interaction between the vaccine and these molecules. In silico cloning confirmed effective expression of the vaccine gene in insect baculovirus vectors. This vaccine-immunoinformatics approach holds promise for the development of vaccines against Mycoplasma pneumoniae and other pathogenic non-viral and non-bacterial microbes. [ABSTRACT FROM AUTHOR]

The vegetative insecticidal protein Vip3Aa from Bacillus thuringiensis (Bt) has been produced by transgenic crops to counter pest resistance to the widely used crystalline (Cry) insecticidal proteins from Bt. To proactively manage pest resistance, there is an urgent need to better understand the genetic basis of resistance to Vip3Aa, which has been largely unknown. We discovered that retrotransposon-mediated alternative splicing of a midgut-specific chitin synthase gene was associated with 5,560-fold resistance to Vip3Aa in a laboratory-selected strain of the fall armyworm, a globally important crop pest. The same mutation in this gene was also detected in a field population. Knockout of this gene via CRISPR/Cas9 caused high levels of resistance to Vip3Aa in fall armyworm and 2 other lepidopteran pests. The insights provided by these results could help to advance monitoring and management of pest resistance to Vip3Aa. The insecticidal protein Vip3Aa is used in genetically engineered crops to overcome pest resistance to other insecticidal transgenes. This study shows that insertion of a transposable element into a gut-specific chitin synthase gene causes Vip3Aa resistance in field-collected individuals of the lepidopteran pest Spodoptera frugiperda (fall armyworm). [ABSTRACT FROM AUTHOR]

Poplar is a valuable tree species that is distributed all over the world. However, many insect pests infest poplar trees and have caused significant damage. To control poplar pests, we transformed a poplar species, Populus davidiana  ×  P. bolleana Loucne, with the dsRNA of the chitinase gene of a poplar defoliator, Clostera anastomosis (Linnaeus) (Lepidoptera: Notodontidae), employing an Agrobaterium -mediated approach. The transgenic plant has been identified by cloning the T-DNA flanking sequences using TAIL-PCR and quantifying the expression of the dsRNA using qPCR. The toxicity assay of the transgenic poplar lines was carried out by feeding the target insect species (C. anastomosis). The results showed that, in C. anastomosis, the activity of chitinase was significantly decreased, consistent with the expression on mRNA levels, and the larval mortality was significantly increased. These results suggested that the transgenic poplar of dsRNA could be used for pest control. [ABSTRACT FROM AUTHOR]

The genetic components of the circadian clock have been implicated as involved in photoperiodic regulation of winter diapause across various insect groups, thereby contributing to adaptation to adverse seasonal conditions. So far, the effects of within‐population variation in these genes have not been well explored. Here, we present an experimental test of the effects of within‐population variation at two circadian genes, timeless and period, on photoperiodic responses in the butterfly Pararge aegeria. While nonsynonymous candidate SNPs in both of these genes have previously shown to be associated with diapause induction on a between‐population level, in the present experiment no such effect was found on a within‐population level. In trying to reconcile these results, we examine sequence data, revealing considerable, previously unknown protein‐level variation at both timeless and period across Scandinavian populations, including variants unique to the population studied here. Hence, we hypothesize that these variants may counteract the previously observed diapause‐averting effect of the candidate SNPs, possibly explaining the difference in results between the experiments. Whatever the cause, these results highlight how the effects of candidate SNPs may sometimes vary across genetic backgrounds, which complicates evolutionary interpretations of geographic patterns of genetic variation. [ABSTRACT FROM AUTHOR]

Gene regulatory network (GRN) comprises complicated yet intertwined gene-regulator relationships. Understanding the GRN dynamics will unravel the complexity behind the observed gene expressions. Insect gene regulation is often complicated due to their complex life cycles and diverse ecological adaptations. The main interest of this review is to have an update on the current mathematical modelling methods of GRNs to explain insect science. Several popular GRN architecture models are discussed, together with examples of applications in insect science. In the last part of this review, each model is compared from different aspects, including network scalability, computation complexity, robustness to noise and biological relevancy. [Display omitted] [ABSTRACT FROM AUTHOR]

Hox genes, specifically the bithorax complex (ubx, abdominal-a, and abdominal-b), play a crucial role in specifying posterior abdominal development and serve as key regulators of germline gene development in insects. However, the function of the bithorax complex in the pine caterpillar moth, Dendrolimus punctatus, a major pine tree defoliator in China, remains largely unknown. Specifically, Abdominal-A (Abd-a) controls regional variation in abdominal segmentation in model insects such as Drosophila and Tribolium; however, its role in D. Punctatus remains unexplored. In this study, CRISPR/Cas9 was used to functionally characterize Abd-a in D. punctatus. Two target sites were selected, and the genotypes and phenotypes of the G0 and G1 generations were evaluated. Our findings indicate that knocking out Abd-a led to an abnormality in the posterior segments A2–A7, as well as the loss of appendages, mainly prolegs, and affected the thoracic T3 segmentation as well as wing development. Moreover, mutation in Abd-a also impacted anal and reproductive development. Taken together, these results demonstrate that DpAbd-a is essential for embryonic and reproductive development in D. punctatus and could be a promising target for genetic control of this devastating conifer defoliator. [ABSTRACT FROM AUTHOR]

Many insects selectively associate with specific microbes in long-term, symbiotic relationships. Maintaining these associations can be vital for the insect hosts' development, but insects must also contend with potential coinfections from other microbes in the environment. Fending off microbial threats while maintaining mutualistic microbes has resulted in many insects developing specialized symbiotic organs to house beneficial microbes. Though locally concentrated in these organs, symbiont establishment can have global consequences for the insect, including influence over the success of coinfecting microbes in colonizing the insect host. We use a transcriptomic approach to examine how the mutualistic symbiosis between the agricultural pest Anasa tristis and bacteria in the genus Caballeronia affects insect gene expression locally within the symbiotic organs and in the insect host at large. We simultaneously determine whether Caballeronia colonization impacts insect host responses to infection with the plant pathogen Serratia marcescens, which it vectors to plants. We found that no significant differential gene expression was elicited by infection with S. marcescens. This was a surprising finding given previous work indicating that symbiotic A. tristis clear S. marcescens infection rapidly compared to aposymbiotic individuals. Our results indicate that symbiotic and nonsymbiotic tissues in A. tristis differ greatly in their gene expression, particularly following successful symbiont colonization. We found evidence for local downregulation of host immunity and upregulation of cell communication within the symbiotic organs, functions which can facilitate the success of the A. tristis-Caballeronia symbiosis. [ABSTRACT FROM AUTHOR]

Sialic acids are nine-carbon sugars that modify glycans on glycoconjugates and mediate important biological functions. While sialic acids have not been detected in insects (as it was considered that it is obtained from external sources), orthologs of sialic acid biosynthetic enzymes and insect ST6Gal sialyltransferases suggest ancestral sialylation pathways. Sialyltransferases contain conserved peptide regions called sialylmotifs (L, S, VS, III), participating in donor substrate binding and catalytic activity. We performed a computational analysis searching 27 insect proteomes for vertebrate sialylmotif sequences to identify putative novel insect sialyltransferases. Sialylmotif L sequences similar to mammalian ST3Gal IV and ST6GalNAc I were found in putative proteins from Galleria mellonella and Manduca sexta, respectively. Identifying sialyltransferase precursor genes in insects supports their evolutionary origin preceding vertebrate diversification. Despite the lack of sialic acid production, sialyltransferase genes in insects suggest an evolutionary perspective on conserved sialylation pathways. [ABSTRACT FROM AUTHOR]

The largest and most diverse group of organisms in the animal kingdom are insects. Molecular markers are powerful tools that can tackle a wide range of insect ecological research issues. These provide a more effective way to study the massive unexplored genetic diversity and gene pool of insects. Recent trends of use of DNA marker techniques in varied domains of insect ecological studies demonstrate that mitochondrial DNA has made a significant contribution towards advancing our knowledge of genetic basis of insect diversity. To shed light on various aspects such as genome organization, base composition, gene rearrangements, and other features, we integrated 165 mitochondrial genomes (mitogenomes) consisting of 37 genes and a noncoding control region, from four major insect orders (Diptera, Lepidoptera, Orthoptera and Hemiptera) for comparative genomic analysis. The same 37 genes were found in the majority of mitochondrial genomes, however the order of genes was found disturbed in a few mitochondrial genomes. The nucleotide composition was found strongly biased towards AT content. Usually, protein-coding genes prefer ATA, ATT and ATG as a canonical start codon. However, inconsistency was observed for few PCGs particularly for COI. The loss of DHU arm was found specific to trnS1 gene. In Zeugodacus tau (Pumpkin fruit fly), trnF gene lacked the TΨC arm. Majority of the mismatches (G-U (most common), U-U, U-C, A-A, A-C, A-G and T-T) were found within the acceptor arm, DHU arm and anticodon stem of tRNA genes but few in TΨC stem. Interestingly, a unique gene rearrangement from trnW (W codes for Tryptophan) to trnU (U codes for Selenocysteine) in the mitochondrial genome of Boettcherisca peregrine (Flesh fly) was observed. AT-rich control region remains highly variable among most of the insects. The review is aimed to draw conclusions for better interpretations of mitochondrial DNA evolution. [ABSTRACT FROM AUTHOR]

Adaptive evolution following colonization can affect the impact of invasive species. The fall webworm (FWW) invaded China 40 years ago through a single introduction event involving a severe bottleneck and subsequently diverged into two genetic groups. The well‐recorded invasion history of FWW, coupled with a clear pattern of genetic divergence, provides an opportunity to investigate whether there is any sign of adaptive evolution following the invasion. Based on genome‐wide SNPs, we identified genetically separated western and eastern groups of FWW and correlated spatial variation in SNPs with geographical and climatic factors. Geographical factors explained a similar proportion of the genetic variation across all populations compared with climatic factors. However, when the two population groups were analysed separately, environmental factors explained more variation than geographical factors. SNP outliers in populations of the western group had relatively stronger response to precipitation than temperature‐related variables. Functional annotation of SNP outliers identified genes associated with insect cuticle protein potentially related to desiccation adaptation in the western group and genes associated with lipase biosynthesis potentially related to temperature adaptation in the eastern group. Our study suggests that invasive species may maintain the evolutionary potential to adapt to heterogeneous environments despite a single invasion event. The molecular data suggest that quantitative trait comparisons across environments would be worthwhile. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides (AMPs) in insects are short peptides that play an important role in their innate defense system. The production of AMPs is typically induced by an infection of pathogenic microorganisms, but cold stress may also cause upregulation of insect AMP genes. However, little is known about the functions of AMPs in cold stress situations and the recovery afterwards. As most important results, in this project with Lasioderma serricorne that can tolerate long storage under cold conditions, we identified and investigated four AMP genes (LsAtt1, LsAtt3, LsCec and LsDef-like). We confirmed their anti-bactericide activity in in vitro assays and in RNAi assays. The cross treatments with cold stress showed that LsDef-like was upregulated under cold stress and its silencing caused a loss of survival. In contrast, the expression of the other three AMPs did not change, and their silencing prolonged the recovery time. We believe that our cross treatments, revealing an association between immune activation and cold stress with AMPs, will increase our basic understanding of the immune system and the “cross-talk” with cold resistance. [ABSTRACT FROM AUTHOR]

Simple Summary: The Keap1-Nrf2-ARE signaling pathway has been suggested to induce the expressions of antioxidant and counter-defense genes, and aid cells in xenobiotic and oxidative responses. Nrf2 is the central transcription factor, and Keap1 is its specific repressor in this signaling pathway. To estimate the function of the Keap1 gene on plant toxin gossypol metabolism, we characterized the pathway in Helicoverpa armigera. The results demonstrated that the suppression of the Keap1 gene not only increased the expressions of three counter-defense genes CYP9A17, CYP4L11 and UGT41B3, but also reduced the larval mortality and promoted the larval development of those treated by the diet with gossypol. Our study showed that Keap1 negatively regulated the transcription of these three counter-defense genes and the knockdown of the Keap1 gene contributed to decreasing the susceptibility to gossypol in the cotton bollworm, which may be beneficial for further research on the regulation of insect counter-defense gene expression and insect–plant interactions. Expressions of a wide range of cytoprotective counter-defense genes are mainly regulated by the Keap1-Nrf2-ARE signaling pathway in response to oxidative stress from xenobiotics. Gossypol is the major antiherbivore secondary metabolite of cotton, but how the polyphagous pest Helicoverpa armigera copes with this phytochemical to utilize its favorite host plant cotton remains largely elusive. In this study, we first suppressed the Keap1 gene in newly hatched larvae of cotton bollworm by feeding them the siRNA diet for 4 days. All of the larvae were subsequently fed the artificial diet supplied with gossypol or the control diet for 5 days. We identified that the knockdown of the Keap1 gene significantly decreased larval mortality and significantly increased the percentages of larval survival, reaching the fourth instar, compared with ncsiRNA when exposed to a diet containing gossypol. Three counter-defense genes CYP9A17, CYP4L11 and UGT41B3, which were related to the induction or metabolism of gossypol according to the report before, were all significantly up-regulated after the knockdown of the Keap1 gene. The Antioxidant Response Elements (AREs) were also detected in the promoter regions of the three counter-defense genes above. These data indicate that the suppression of the Keap1 gene activates the Keap1-Nrf2-ARE signaling pathway, up-regulates the expressions of counter-defense genes involved in the resistance of oxidative stress and finally contributes to reducing the susceptibility of gossypol. Our results provide more knowledge about the transcriptional regulation mechanisms of counter-defense genes that enable the cotton bollworm to adapt to the diversity of host plants including cotton. [ABSTRACT FROM AUTHOR]

The system of gulcosinoalte sulfatase–sulfatase‐modifying factors (Sumfs) in herbivorous insects fulfils an essential function in defending host plant glucosinolates (GLSs)—the compounds of cruciferous plants—by swiftly desulfurising them. Previously, eight HaSulfs and one HaSumf1 were identified in Helicoverpa armigera. GLSs have a significant impact on the growth and development of H. armigera larvae. They can induce the expression of HaSulf in the midgut of H. armigera at both gene and protein levels. In the present study, we utilised RNAi technology to silence the HaSumf1 gene and explored its potential impact on the growth, development, and adaptation of GLSs. The sequence analysis has indicated that the HaSumf1 gene in H. armigera shares a high degree of sequence identity with other insect genes and is expressed at its highest level in the fifth‐instar phase. Additionally, the qRT‐PCR results reveal that the expression of HaSumf1 was upregulated by 1.26 and 0.07 times in third‐instar and 1.65 and 0.19 times in fifth‐instar when fed with 0.004% and 0.04% GLS, respectively. The effectiveness of dsSumf1 silencing was observed in both third‐ and fifth‐instar stages, with silencing rates of 65.5%–88.9% and 61.3%–74.6%, respectively (p < 0.05). The findings of the bioassay indicate that H. armigera's body weight at fifth‐instar significantly increased after treatment with 0.004% GLS and 0.04% GLS, while the larval survival rate, pupation rate, and pupa weight decreased. Notably, when feeding dsRNA‐encapsulated carbon quantum dots (CQD‐dsRNA), this trend was significantly strengthened (p < 0.05). Taken together, these findings provide evidence supporting HaSumf1's conservation involvement in the adaptation of host plant GLSs during lepidopteran insect evolution. Therefore, it plays a critical role in the growth and development of H. armigera, offering molecular targets for developing novel pesticides and targeted control measures against this vital pest. [ABSTRACT FROM AUTHOR]

Simple Summary: Mating behavior plays a crucial role in the survival and reproduction of insect populations. The fruitless (fru) gene, recognized for regulating male mating behaviors in Drosophila melanogaster, acts as a central "tuner", shaping courtship behavior through sex-specific expression patterns within the courtship neural circuit. While fru homologs and sex-specific isoforms have been identified in other holometabolan insects, controlling mating behavior, hemimetabolous insects show the generation of non-sex-specific mRNAs by the fru gene, suggesting potential functional differences. This study focuses on fru homologs (Nlfru) in the Hemiptera species Nilaparvata lugens, utilizing RNAi-mediated knockdown to explore Nlfru functions in male mating behavior and tissue development. Our research contributes to understanding the regulation of mating behavior in N. lugens and sheds light on the evolution of the fru gene across insect species. The fruitless (fru) gene functions as a crucial "tuner" in male insect courtship behavior through distinct expression patterns. In Nilaparvata lugens, our previous research showed doublesex (dsx) influencing male courtship songs, causing mating failures with virgin females. However, the impact of fru on N. lugens mating remains unexplored. In this study, the fru homolog (Nlfru) in N. lugens yielded four spliceosomes: Nlfru-374-a/b, Nlfru-377, and Nlfru-433, encoding proteins of 374aa, 377aa, and 433aa, respectively. Notably, only Nlfru-374b exhibited male bias, while the others were non-sex-specific. All NlFRU proteins featured the BTB conserved domain, with NlFRU-374 and NlFRU-377 possessing the ZnF domain with different sequences. RNAi-mediated Nlfru or its isoforms' knockdown in nymph stages blocked wing-flapping behavior in mating males, while embryonic knockdown via maternal RNAi resulted in over 80% of males losing wing-flapping ability, and female receptivity was reduced. Nlfru expression was Nldsx-regulated, and yet courtship signals and mating success were unaffected. Remarkably, RNAi-mediated Nlfru knockdown up-regulated the expression of flightin in macropterous males, which regulated muscle stiffness and delayed force response, suggesting Nlfru's involvement in muscle development regulation. Collectively, our results indicate that Nlfru functions in N. lugens exhibit a combination of conservation and species specificity, contributing insights into fru evolution, particularly in Hemiptera species. [ABSTRACT FROM AUTHOR]

Pheromones play an important role in mate choice in insects, and pheromone synthesis pathways are potential targets for the control of harmful insects, among which desaturation is of great significance in pheromone structural diversity. However, little is known about the desaturase genes regulating pheromone synthesis in Coleoptera. In this study, taking the internationally significant pest Anoplophora glabripennis as a research object, we identified 6 AglaFAD genes, all of which were mapped to the endoplasmic reticulum and shared a highly similar distribution of conserved domains. A phylogenetic analysis showed that AglaFAD1–2 and AglaFAD3–6 exerted desaturation at different positions of the acyl chain, respectively. In regard to the expression levels of these six AglaFADs in both sexes, six tissues and three developmental stages were analyzed by qPCR. Combined with the chemical composition of the female pheromones that have been identified, two candidate genes, AglaFAD2 and AglaFAD5, which are specifically expressed in females, were screened, showing higher expression levels before mating and significantly decreasing after mating. It is speculated that they may be involved in the biosynthesis of contact pheromones in females. These results provide a basis for detailed functional studies of candidate genes in insect pheromone synthesis. [ABSTRACT FROM AUTHOR]

BACKGROUND: The sugarcane borer Diatraea saccharalis (Lepidoptera) is a key pest on sugarcane and other grasses in the Americas. Biological control as well as insecticide treatments are used for pest management, but economic losses are still significant. The use of female sex pheromones for mating disruption or mass trapping in pest management could be established for this species, provided that economical production of pheromone is available. RESULTS: Combining in vivo labelling studies, differential expression analysis of transcriptome data and functional characterisation of insect genes in a yeast expression system, we reveal the biosynthetic pathway and identify the desaturase and reductase enzymes involved in the biosynthesis of the main pheromone component (9Z,11E)‐hexadecadienal, and minor components hexadecanal, (9Z)‐hexadecenal and (11Z)‐hexadecenal. We next demonstrate heterologous production of the corresponding alcohols of the pheromone components, by expressing multiple steps of the biosynthetic pathway in yeast. CONCLUSION: Elucidation of the genetic basis of sex pheromone biosynthesis in D. saccharalis, and heterologous expression in yeast, paves the way for biotechnological production of the pheromone compounds needed for pheromone‐based pest management of this species. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Due to being rooted in the ground, maize (Zea mays L.) is unable to actively escape the attacks of herbivorous insects such as the Asian corn borer (Ostrinia furnacalis). In contrast to the passive damage, plants have evolved defense mechanisms to protect themselves from herbivores. Salicylic acid, a widely present endogenous hormone in plants, has been found to play an important role in inducing plant resistance to insects. In this study, we screened and identified the insect resistance gene SPI, which is simultaneously induced by SA and O. furnacalis feeding, through preliminary transcriptome data analysis. The functional validation of SPI was carried out using bioinformatics, RT-qPCR, and heterologous expression protein feeding assays. Results: Both SA and O. furnacalis treatment increased the expression abundance of SA-synthesis pathway genes and SPI in three maize strains, and the upregulation of SPI was observed strongly at 6 hours post-treatment. The expression of SPI showed a temporal relationship with SA pathway genes, indicating that SPI is a downstream defense gene regulated by SA. Protein feeding assays using two different expression vectors demonstrated that the variation in SPI protein activity among different strains is mainly due to protein modifications. Conclusions: Our research results indicate that SPI, as a downstream defense gene regulated by SA, is induced by SA and participates in maize's insect resistance. The differential expression levels of SPI gene and protein modifications among different maize strains are one of the reasons for the variation in insect resistance. This study provides new insights into ecological pest control in maize and valuable insights into plant responses to SA-induced insect resistance. [ABSTRACT FROM AUTHOR]

The evolutionary dynamics of large gene families can offer important insights into the functions of their individual members. While the ecdysteroid kinase-like (EcKL) gene family has previously been linked to the metabolism of both steroid molting hormones and xenobiotic toxins, the functions of nearly all EcKL genes are unknown, and there is little information on their evolution across all insects. Here, we perform comprehensive phylogenetic analyses on a manually annotated set of EcKL genes from 140 insect genomes, revealing the gene family is comprised of at least 13 subfamilies that differ in retention and stability. Our results show the only two genes known to encode ecdysteroid kinases belong to different subfamilies and therefore ecdysteroid metabolism functions must be spread throughout the EcKL family. We provide comparative phylogenomic evidence that EcKLs are involved in detoxification across insects, with positive associations between family size and dietary chemical complexity, and we also find similar evidence for the cytochrome P450 and glutathione S-transferase gene families. Unexpectedly, we find that the size of the clade containing a known ecdysteroid kinase is positively associated with host plant taxonomic diversity in Lepidoptera, possibly suggesting multiple functional shifts between hormone and xenobiotic metabolism. Our evolutionary analyses provide hypotheses of function and a robust framework for future experimental studies of the EcKL gene family. They also open promising new avenues for exploring the genomic basis of dietary adaptation in insects, including the classically studied coevolution of butterflies with their host plants. [ABSTRACT FROM AUTHOR]

α-Farnesene, a crucial secondary metabolite in sesquiterpenes, is crucial for plant biotic and abiotic stress resistance. In this study, we screened an AFS gene from transcriptome data of tea plants (Camellia sinensis) intercropped with Chinese chestnut (Castanea mollissima), resulting in the cloning of CsAFS2. CsAFS2 expression increased following treatment with MJ (Methyl jasmonate), SA (Salicylic acid), GA3 (Gibberellin A3), and various plant growth regulators, as well as under high-salt, drought, and low-temperature conditions. The heterologous genetic transformation of tobacco with CsAFS2 led to an enhanced resistance to low-temperature stress and aphid feeding, evident from elevated levels of osmotic regulatory substances, increased protective enzyme activity, and the upregulation of cold and insect resistance-related genes. Trichomes, crucial in cold and insect resistance, exhibited significantly greater length and density in transgenic tobacco as compared to control plants. These results confirm the vital role of CsAFS2 in enhancing cold and insect resistance, providing comprehensive insights into stress regulation mechanisms in tea plants and advancing stress-resistant tea plant breeding. [ABSTRACT FROM AUTHOR]

Insects pose significant challenges in cotton‐producing regions. Here, they describe a high‐throughput CRISPR/Cas9‐mediated large‐scale mutagenesis library targeting endogenous insect‐resistance‐related genes in cotton. This library targeted 502 previously identified genes using 968 sgRNAs, generated ≈2000 T0 plants and achieved 97.29% genome editing with efficient heredity, reaching upto 84.78%. Several potential resistance‐related mutants (10% of 200 lines) their identified that may contribute to cotton‐insect molecular interaction. Among these, they selected 139 and 144 lines showing decreased resistance to pest infestation and targeting major latex‐like protein 423 (GhMLP423) for in‐depth study. Overexpression of GhMLP423 enhanced insect resistance by activating the plant systemic acquired resistance (SAR) of salicylic acid (SA) and pathogenesis‐related (PR) genes. This activation is induced by an elevation of cytosolic calcium [Ca2+]cyt flux eliciting reactive oxygen species (ROS), which their demoted in GhMLP423 knockout (CR) plants. Protein‐protein interaction assays revealed that GhMLP423 interacted with a human epidermal growth factor receptor substrate15 (EPS15) protein at the cell membrane. Together, they regulated the systemically propagating waves of Ca2+ and ROS, which in turn induced SAR. Collectively, this large‐scale mutagenesis library provides an efficient strategy for functional genomics research of polyploid plant species and serves as a solid platform for genetic engineering of insect resistance. [ABSTRACT FROM AUTHOR]

The Hox gene cluster is an iconic example of evolutionary conservation between divergent animal lineages, providing evidence for ancient similarities in the genetic control of embryonic development. However, there are differences between taxa in gene order, gene number and genomic organisation implying conservation is not absolute. There are also examples of radical functional change of Hox genes; for example, the ftz , zen and bcd genes in insects play roles in segmentation, extraembryonic membrane formation and body polarity, rather than specification of anteroposterior position. There have been detailed descriptions of Hox genes and Hox gene clusters in several insect species, including important model systems, but a large-scale overview has been lacking. Here we extend these studies using the publicly-available complete genome sequences of 243 insect species from 13 orders. We show that the insect Hox cluster is characterised by large intergenic distances, consistently extreme in Odonata, Orthoptera, Hemiptera and Trichoptera, and always larger between the 'posterior' Hox genes. We find duplications of ftz and zen in many species and multiple independent cluster breaks, although certain modules of neighbouring genes are rarely broken apart suggesting some organisational constraints. As more high-quality genomes are obtained, a challenge will be to relate structural genomic changes to phenotypic change across insect phylogeny. [ABSTRACT FROM AUTHOR]

Simple Summary: Aglais urticae (Lepidoptera, Nymphalid) is a common butterfly distributed in temperate regions worldwide. The nettle Urtica cannabina (Urticaceae) is key to the survival of the small tortoiseshell, which provides its primary food source. This species is also a toxic plant listed in the Chinese Flora Atlas database, as it has poisonous roots and leaves. However, the phytophagous insect has evolved different adaptations against the plant′s defense system. This study aims to identify the genes linked to feeding strategies and adaptations of Aglais urticae's larval feeding preference and detoxifying mechanism, and it may serve as an approach to help us understand the molecular process of its in vivo detoxification and find its related genes. Overall, these results provide the basis for future work on the detoxification and development of phytophagous insects by identifying the detoxification mechanism of A. urticae and their development-related genes in holometabolous insects. Herbivorous insects and host plants have developed a close and complex relationship over a long period of co-evolution. Some plants provide nutrients for insects, but plants' secondary metabolites also influence their growth and development. Urtica cannabina roots and leaves are poisonous, yet Aglais urticae larvae feed on them, so we aimed to clarify the mechanism enabling this interaction. At present, studies on the detoxification mechanism of the A. urticae are rare. In our study, first, we used the A. urticae larval odor selection behavior bioassay and choice feeding preference assay to analyze the feeding preferences of A. urticae on its host plant, U. cannabina. Next, we used transcriptome sequencing to obtain the unigenes annotated and classified by various databases, such as KEGG and GO. In this study, we found that U. cannabina could attract A. urticae larvae to feed via scent, and the feeding preference assay confirmed that larvae preferred U. cannabina leaves over three other plants: Cirsium japonicum, Cannabis sativa, and Arctium lappa. The activity of detoxifying enzymes GST and CarE changed in larvae that had consumed U. cannabina. Furthermore, through transcriptomic sequencing analysis, 77,624 unigenes were assembled from raw reads. The numbers of differentially expressed genes were calculated using pairwise comparisons of all life stages; the expression of detoxification enzyme genes was substantially higher in larvae than in the pupal and adult stages. Finally, we identified and summarized 34 genes associated with detoxification enzymes, such as UDP-glucose 4-epimerase gene, 5 Glutathione S-transferase genes, 4 Carboxylesterase genes, 4 Cytochrome P450 genes, 10 ATP-binding cassette genes, 4 Superoxide dismutase, and Peroxidase. Moreover, we identified 28 genes associated with the development of A. urticae. The qRT-PCR results were nearly consistent with the transcriptomic data, showing an increased expression level of four genes in larvae. Taken together, this study examines the correlation between A. urticae and host plants U. cannabina, uncovering a pronounced preference for A. urticae larvae toward host plants. Consistent with RNA-seq, we investigated the mechanism of A. urticae's interaction with host plants and identified detoxification-related genes. The present study provides theoretical support for studying insect adaptation mechanisms and biological control. [ABSTRACT FROM AUTHOR]

Cytochrome b561 (cytb561) proteins comprise a family of transmembrane oxidoreductases that transfer single electrons across a membrane. Most eukaryotic species, including insects, possess multiple cytb561 homologs. To learn more about this protein family in insects, we carried out a bioinformatics-based investigation of cytb561 family members from nine species representing eight insect orders. We performed a phylogenetic analysis to classify insect cytb561 ortholog groups. We then conducted sequence analyses and analyzed protein models to predict structural elements that may impact the biological functions and localization of these proteins, with a focus on possible ferric reductase activity. Our study revealed three ortholog groups, designated CG1275, Nemy, and CG8399, and a fourth group of less-conserved genes. We found that CG1275 and Nemy proteins are similar to a human ferric reductase, duodenal cytochrome b561 (Dcytb), and have many conserved amino acid residues that function in substrate binding in Dcytb. Notably, CG1275 and Nemy proteins contain a conserved histidine and other residues that play a role in ferric ion reduction by Dcytb. Nemy proteins were distinguished by a novel cysteine-rich cytoplasmic loop sequence. CG8399 orthologs are similar to a putative ferric reductase in humans, stromal cell-derived receptor 2. Like other members of the CYBDOM class of cytb561 proteins, these proteins contain reeler, DOMON, and cytb561 domains. Drosophila melanogaster CG8399 is the only insect cytb561 with known ferric reductase activity. Our investigation of the DOMON domain in CG8399 proteins revealed a probable heme-binding site and a possible site for ferric reduction. The fourth group includes a subgroup of proteins with a conserved "KXXXXKXH" non-cytoplasmic loop motif that may be a substrate binding site and is present in a potential ferric reductase, human tumor suppressor cytochrome b561. This study provides a foundation for future investigations of the biological functions of cytb561 genes in insects. [ABSTRACT FROM AUTHOR]

Simple Summary: Reference genes serve as a foundation for investigating the functionality of target genes in insects. Nevertheless, the selection of reference genes is highly dependent upon particular experimental circumstances. Recently, the bean bug, Riptortus pedestris (Hemiptera: Alydidae), has attracted increasing attention due to its damage on yield losses of soybean crops. However, there is a dearth of literature regarding the evaluation of reference genes for quantitative real-time PCR (qRT-PCR) in R. pedestris. The current study aimed to assess the stability of expression levels in 16 candidate reference genes in R. pedestris across six experimental conditions. This evaluation was conducted using ΔCt method, GeNorm, NormFinder, BestKeeper, and RefFinder. Our results indicate that the optimum reference genes were as follows: RPL7A and EF1 for the developmental stage, α−tubulin and EF1 for adult tissues, RPL32 and RPL7A for adult age, RPL32 and SOD for nymph age, RPS23 and RPL7A for temperature, and HSP70 and GAPDH for mating status. These findings will provide a basis for future investigations into the expression and function of target genes in bean bugs. Quantitative real-time PCR (qRT-PCR) is widely accepted as a precise and convenient method for quantitatively analyzing the expression of functional genes. The data normalization strongly depends upon stable reference genes. The bean bug, Riptortus pedestris (Hemiptera: Alydidae), is a significant pest of leguminous crops and broadly distributed across Southeast Asia. In this study, a total of 16 candidate reference genes (RPL32, RPS23, SDHA, UBQ, UCCR, GST, TATA−box, HSP70, GAPDH, RPL7A, SOD, RPS3, Actin, α−tubulin, AK, and EF1) were carefully chosen in R. pedestris, and their expression levels were assessed across various conditions, including different developmental stages, diverse tissues, temperature treatments, adult age, molting time, and mating status. Following this, the stability of these reference genes was evaluated using four algorithms (ΔCt, GeNorm, NormFinder, and BestKeeper). Ultimately, the comprehensive rankings were determined using the online tool RefFinder. Our results demonstrate that the reference gene for qRT-PCR analysis in R. pedestris is contingent upon the specific experimental conditions. RPL7A and EF1 are optimal reference genes for developmental stages. Furthermore, α−tubulin and EF1 exhibit the most stable expression across various adult tissues. RPL32 and RPL7A exhibit the most stable expression for adult age. For nymph age, RPL32 and SOD display the most stable expression. For temperature conditions, RPS23 and RPL7A were identified as the most suitable for monitoring gene expression. Lastly, we verified the practicability of evaluating expression levels of odorant-binding protein 37 (RpedOBP37) and cytochrome P450 6a2 (RpedCYP6) throughout developmental stages, tissues, and temperature conditions. These findings are a significant addition to the qRT-PCR analysis studies on R. pedestris, serving as a fundamental groundwork for future investigations on stable reference genes in R. pedestris as well as other organisms. [ABSTRACT FROM AUTHOR]

Serine protease inhibitors (serpins) appear to be ubiquitous in almost all living organisms, with a conserved structure and varying functions. Serpins can modulate immune responses by negatively regulating serine protease activities strictly and precisely. The codling moth, Cydia pomonella (L.), a major invasive pest in China, can cause serious economic losses. However, knowledge of serpin genes in this insect remain largely unknown. In this study, we performed a systematic analysis of the serpin genes in C. pomonella, obtaining 26 serpins from the C. pomonella genome. Subsequently, their sequence features, evolutionary relationship, and expression pattern were characterized. Comparative analysis revealed the evolution of a number of serpin genes in Lepidoptera. Importantly, the evolutionary relationship and putative roles of serpin genes in C. pomonella were revealed. Additionally, selective pressure analysis found amino acid sites with strong evidence of positive selection. Interestingly, the serpin1 gene possessed at least six splicing isoforms with distinct reactive-center loops, and these isoforms were experimentally validated. Furthermore, we observed a subclade expansion of serpins, and these genes showed high expression in multiple tissues, suggesting their important roles in C. pomonella. Overall, this study will enrich our knowledge of the immunity of C. pomonella and help to elucidate the role of serpins in the immune response. [ABSTRACT FROM AUTHOR]

This article, published in the journal Environment & Ecology, examines the settlement behavior of crawlers of the Rangeeni strain of lac insect on different host plants. The study found that crawlers traveled the greatest distance on Acacia host plants and the least distance on Kikar and Custard Apple host plants. The diameter of the host twig was negatively correlated with the first settlement of crawlers. Settlement density was higher in the north and south directions compared to the east and west directions. The findings suggest that the location and configuration of host plants can impact lac production. [Extracted from the article]

PIWI-interacting RNAs (piRNAs) guide PIWI proteins to target transposons in germline cells, thereby suppressing transposon activity to preserve genome integrity in metazoans' gonadal tissues. Piwi, one of three Drosophila PIWI proteins, is expressed in the nucleus and suppresses transposon activity by forming heterochromatin in an RNA cleavage-independent manner. Recently, Piwi was reported to control cell metabolism in Drosophila fat body, providing an example of piRNAs acting in non-gonadal somatic tissues. However, mutant flies of the other two PIWI proteins, Aubergine (Aub) and Argonaute3 (Ago3), show no apparent phenotype except for infertility, blurring the importance of the piRNA pathway in non-gonadal somatic tissues. The silkworm, Bombyx mori, possesses two PIWI proteins, Siwi (Aub homolog) and BmAgo3 (Ago3 homolog), whereas B. mori does not have a Piwi homolog. Siwi and BmAgo3 are mainly expressed in gonadal tissues and play a role in repressing transposon activity by cleaving transposon RNA in the cytoplasm. Here, we generated Siwi and BmAgo3 loss-of-function mutants of B. mori and found that they both showed delayed larval growth and failed to become adult moths. They also exhibited defects in wing development and sexual differentiation. Transcriptome analysis revealed that loss of somatic piRNA biogenesis pathways results in abnormal expression of not only transposons but also host genes, presumably causing severe growth defects. Our results highlight the roles of non-gonadal somatic piRNAs in B. mori development. Author summary: In animal germ cells, PIWI proteins and piRNAs play an important role in the defense system against selfish elements such as transposons. The fruit fly Drosophila possesses two PIWI proteins, Aub and Ago3, both of which are required for piRNA production and transposon repression in the cytoplasm of germ cells. However, their roles in somatic cells are unclear. Using a lepidopteran model insect, the silkworm Bombyx mori, we established Siwi (Aub homolog) and BmAgo3 (Ago3 homolog) germline knockout mutants and characterized non-gonadal somatic piRNA functions in B. mori development. We found that somatic piRNAs are utilized to suppress transposon activity and maintain normal gene expression in several somatic tissues. Unlike Drosophila, disruption of somatic piRNA pathways severely inhibited normal development in somatic tissues of B. mori: both mutants grew slowly, did not develop to adult moths, and exhibited defects in wing development and sexual differentiation. This study is the first to generate germline knockout insects of PIWI genes in non-Drosophila insects and expands the knowledge on the ancestral or universal functions of piRNAs in arthropods. [ABSTRACT FROM AUTHOR]

Background: The jasmonate ZIM domain (JAZ) protein is a key repressor of the jasmonate signal transduction pathway, which plays an important role in plant growth and development and defense responses. In this study, based on the published whole-genome data, we identified members of the JAZ gene family in Populus trichocarpa. Through a series of bioinformatic approaches, their expression patterns under various stress conditions have been analyzed to explore and excavate the endogenous resistance genes of poplar and provide a theoretical basis for breeding new varieties of poplar resistance. Results: A total of 13 PtJAZ genes have been identified in P. trichocarpa and designated as PtJAZ1–PtJAZ13. Those 13 PtJAZ genes were unevenly distributed on nine chromosomes, and they could be divided into four subfamilies. The gene structures and motif composition of the members derived from the same subfamily were similar. Collinearity analysis demonstrated that, compared with Arabidopsis thaliana and Oryza sativa, the most collinear pairs (13) were found in P. trichocarpa and Eucalyptus robusta. Cis-acting element analysis suggested that the promoter regions of PtJAZs contained a large number of hormones and stress response elements, of which abscisic acid (ABA) and methyl jasmonate (MeJA) hormone response elements were the most abundant. The PtJAZ genes not only had diverse expression patterns in different tissues, but they also responded to various abiotic and biotic stress conditions. The co-expression network and GO and KEGG analyses showed that JAZ genes were closely related to insect resistance. Conclusions: In this study, applying bioinformatic methods, 13 PtJAZ gene family members from P. trichocarpa were identified and comprehensively analyzed. By further studying the function of the poplar JAZ gene family, the aim is to select genes with better insect resistance and stress resistance so as to lay a solid foundation for the subsequent breeding of new poplar varieties. [ABSTRACT FROM AUTHOR]

BPH (brown planthopper) and WBPH (white backed planthopper) are significant rice pests that often co-occur as sympatric species and cause substantial yield loss. Despite their genetic similarities, different host-resistance genes confer resistance against these two hoppers. The defense mechanisms in rice against these pests are complex, and the molecular processes regulating their responses remain largely unknown. This study used specific recombinant inbred lines (RILs) derived from a cross between rice varieties RP2068-18-3-5 (BPH- and WBPH-resistant) and TN1 (BPH- and WBPH-susceptible) to investigate the mechanisms of interaction between these planthoppers and their rice hosts. WBPH and BPH were allowed to feed on specific RILs, and RNA-Seq was carried out on WBPH insects. Transcriptome profiling and qRT-PCR results revealed differential expression of genes involved in detoxification, digestion, transportation, cuticle formation, splicing, and RNA processing. A higher expression of sugar transporters was observed in both hoppers feeding on rice with resistance against either hopper. This is the first comparative analysis of gene expressions in these insects fed on genetically similar hosts but with differential resistance to BPH and WBPH. These results complement our earlier findings on the differential gene expression of the same RILs (BPH- or WBPH-infested) utilized in this study. Moreover, identifying insect genes and pathways responsible for countering host defense would augment our understanding of BPH and WBPH interaction with their rice hosts and enable us to develop lasting strategies to control these significant pests. [ABSTRACT FROM AUTHOR]

Various plant species contain terpene secondary metabolites, which disrupt insect growth and development by affecting the activity of juvenile hormone-degrading enzymes, and the juvenile hormone (JH) titers maintained in insects. Nerolidol, a natural sesquiterpenol belonging to the terpenoid group, exhibits structural similarities to insect JHs. However, the impact of nerolidol on insect growth and development, as well as its underlying molecular mechanism, remains unclear. Here, the effects of nerolidol on Spodoptera exigua were investigated under treatment at various sub-lethal doses (4.0 mg/mL, 1.0 mg/mL, 0.25 mg/mL). We found that a higher dose (4.0 mg/mL) of nerolidol significantly impaired the normal growth, development, and population reproduction of S. exigua, although a relatively lower dose (0.25 mg/mL) of nerolidol had no significant effect on this growth and development. Combined transcriptome sequencing and gene family analysis further revealed that four juvenile hormone esterase (JHE)-family genes that are involved in juvenile hormone degradation were significantly altered in S. exigua larvae after nerolidol treatment (4.0 mg/mL). Interestingly, the juvenile hormone esterase-like (JHEL) gene Sexi006721, a critical element responsive to nerolidol stress, was closely linked with the significant augmentation of JHE activity and JH titer in S. exigua (R2 = 0.94, p < 0.01). Taken together, we speculate that nerolidol can function as an analog of JH by modulating the expression of the enzyme genes responsible for degrading JH, resulting in JH disorders and ultimately disrupting the development of insect larvae. This study ultimately provides a theoretical basis for the sustainable control of S. exigua in the field whilst proposing a new perspective for the development of novel biological pesticides. [ABSTRACT FROM AUTHOR]

Lethal bronzing (LB) and huanglongbing (HLB) are harmful plant diseases causing significant economic losses in Florida agriculture. Both diseases are caused by bacteria that are transmitted by Hemipteran insect vectors. Accurate detection of pathogens within insect vectors can help provide a better understanding of disease epidemiology. Monitoring of the vector of LB is done primarily using sticky traps within palm canopies. However, it is unknown how long pathogen and vector DNA remain intact under field conditions. If significant DNA degradation takes place over the course of days or weeks, there is a possibility of false negatives occurring when detecting pathogens from these surveys. This study determined how long Haplaxius crudus Van Duzee (Hemiptera: Cixiidae) and LB DNA could remain detectable on sticky traps under field conditions in Florida in winter and summer, using PCR and qPCR. Additionally, this study compared the DNA degradation of Diaphorina citri Kuwayama (Hemiptera: Liviidae) and Candidatus Liberibacter asiaticus (CLas), the causal agent of HLB. The results showed that DNA concentration and amplification rate declined as time on sticky traps increased. Degradation varied between different target genes. The amplification rate of insect genes from sticky trap samples suggests that sticky traps should be changed weekly in summer, and every 2 wk in winter for accurate H. crudus detection. Traps should be changed every 4 days for phytoplasma detection. Traps can be changed monthly for accurate D. citri and CLas detection. Based on these results, standard monitoring protocols can be implemented to more accurately detect vectors and pathogens. [ABSTRACT FROM AUTHOR]

Simple Summary: The study of whole-genome sequences, combined with advanced bioinformatic tools, has revolutionized our understanding of the evolutionary history of genes and genomes. Here, we have highlighted the conservation of a putative regulatory element in insect genes encoding for an important enzymatic complex of the vacuolar and lysosomal compartments of the eukaryotic cell with storage and recycling functions, respectively. This study will enable future investigations aimed at understanding regulative circuits that generate cellular complexity. Gene and genome comparison represent an invaluable tool to identify evolutionarily conserved sequences with possible functional significance. In this work, we have analyzed orthologous genes encoding subunits and assembly factors of the V-ATPase complex, an important enzymatic complex of the vacuolar and lysosomal compartments of the eukaryotic cell with storage and recycling functions, respectively, as well as the main pump in the plasma membrane that energizes the epithelial transport in insects. This study involves 70 insect species belonging to eight insect orders. We highlighted the conservation of a short sequence in the genes encoding subunits of the V-ATPase complex and their assembly factors analyzed with respect to their exon-intron organization of those genes. This study offers the possibility to study ultra-conserved regulatory elements under an evolutionary perspective, with the aim of expanding our knowledge on the regulation of complex gene networks at the basis of organellar biogenesis and cellular organization. [ABSTRACT FROM AUTHOR]

Macrosiphoniella sanborni is a widespread pest of Chrysanthemum morifolium that causes significant damage to world floriculture. Chemical insecticides and biological methods of control have a number of disadvantages that can be improved by using oligonucleotide insecticides. In this article, we present, for the first time, the results of using oligonucleotide insecticides, for which the target sequence is an internal transcribed spacer (ITS) in a polycistronic rRNA transcript. The mortality of wingless aphid individuals after a Macsan-11 treatment was recorded at a level of 67.15 ± 3.32% 7 days after a single treatment with a solution at a concentration of 100 ng/μL and 97.38 ± 2.49% 7 days after a double treatment with a solution of the same concentration and a daily interval. The contact use of the control oligonucleotide (ACTG)2ACT-11. as well as the oligonucleotide insecticides Macsan-11(3′) and Macsan-11(5′) was not accompanied by insect mortality. Given the high variability in the internal transcribed spacer, which has proven to be a promising target for the action of oligonucleotide insecticides, it is possible to create selective preparations. This study showed the prospects of ribosomal insect pest genes as targets for the action of olinscides, and also demonstrated the high specificity of such insecticidal agents. [ABSTRACT FROM AUTHOR]