Chromosome-level genome assembly of cotton thrips Thrips tabaci (Thysanoptera: Thripidae).

Cotton thrip, Thrips tabaci is a major polyphagous pest widely distributed on a variety of crops around the world, causing huge economic losses to agricultural production. Due to its biological and genomic characteristics, this pest can reproduce quickly and develop resistance to various pesticides in a very short time. However, the lack of high-quality reference genomes has hindered deeper gene function exploration and slows down the development of new management strategies. Here, we assembled a high-quality genome of T. tabaci at the chromosome level for the first time by using Illumina, PacBio long reads, and Hi-C technologies. The 329.59 Mb genome was obtained from 320 contigs, with a contig N50 of 1.53 Mb, and 94.21% of the assembly was anchored to 18 chromosomes. In total, 17,816 protein-coding genes were annotated, and 96.78% of BUSCO genes were fully represented. In conclusion, this high-quality genome provides a valuable genetic basis for our understanding of the biology of T. tabaci and contributes to the development of management strategies for cotton thrip.

Chromosome-level genome assembly of the planthopper Nilaparvata muiri.

The Nilaparvata muiri (Hemiptera: Delphacidae) is a sibling species of a destructive rice insect pest, the brown planthopper (BPH), Nilaparvata lugens. Here, we generated a high-quality chromosome-level genome assembly of N. muiri using a combination of the PacBio HiFi sequencing, Illumina short-read sequencing and Hi-C scaffolding technologies. The genome assembly (524.9 Mb) is anchored to 15 pseudochromosomes, with a scaffold N50 of 43.3 Mb and 99.1% BUSCO completeness. It contains 188.1 Mb repeat sequences and 13204 protein-coding genes. As a closely related species within the same genus as the significant pest, N. lugens, the chromosome-level genome assembly of N. muiri will provide important support for the better analysis of pathogenicity mechanisms of N. lugens based on comparative genomics.

Chromosome-level genome assembly of predatory Arma chinensis.

Arma chinensis is a natural enemy that preys on various species and can suppress agricultural and forest pests in the orders Lepidoptera and Coleoptera. Here, we aimed to determine the genome of A. chinensis assembled at the chromosome-level using PacBio and Hi-C technologies. The assembled genome was 986 Mb, with a contig N50 of 2.40 Mb, scaffold N50 of 134.98 Mb, and BUSCO completeness of 96.10%. Hi-C data aided in anchoring the assembly onto seven chromosomes. A sequence of ~ 496.2 Mb was annotated as a repeat element, constituting 51.15% of the genome. We functionally annotated 84.79% of 20,853 predicted protein-encoding genes. This high-quality A. chinensis genome provides a novel genomic resource for future research on Pentatomidae insects.

Chromosome-level genome assembly of the forest pest Achelura yunnanensis (Lepidoptera: Zygaenidae).

Achelura yunnanensis is a destructive pest of forests, causing substantial damage on tree growth and severe economic losses. Additionally, as a daytime-active moth, this species also holds important scientific value for investigating the genetic mechanisms governing day-night activity patterns of Lepidoptera. To facilitate effective pest control and deepen our understanding of the diurnal behavior's genetic basis of moths, genomic data for this species are crucial. In this study, we present a chromosome-level reference genome of A. yunnanensis (368.15 Mb in 32 chromosomes; scaffold N50 = 12.61 Mb; BUSCO completeness = 98.0%). Genome annotation shows that the new assembly comprises 37.10% (136.55 Mb) repetitive elements, 1,828 non-coding RNAs, and 15,523 protein-coding genes. Genes involved in lipid metabolism and xenobiotics biodegradation and metabolism, such as cytochrome P450 families, experienced significant expansion in the A. yunnanensis genome. The chromosome-level genome of A. yunnanensis provides a valuable genomic resource for devising novel pest control strategies, and will also help to study the genetic mechanism of the shift of diurnal behavior in Lepidoptera.

Chromosome-level genome assembly of the morabine grasshopper Vandiemenella viatica19.

Morabine grasshoppers in the Vandiemenella viatica species group, which show karyotype diversity, have been studied for their ecological distribution and speciation in relation to their genetic and chromosomal diversity. They are good models for studying sex chromosome evolution as "old" and newly emerged sex chromosomes co-exist within the group. Here we present a reference genome for the viatica19 chromosomal race, that possesses the ancestral karyotype within the group. Using PacBio HiFi and Hi-C sequencing, we generated a chromosome-level assembly of 4.09 Gb in span, scaffold N50 of 429 Mb, and complete BUSCO score of 98.1%, containing 10 pseudo-chromosomes. We provide Illumina datasets of males and females, used to identify the X chromosome. The assembly contains 19,034 predicted protein-coding genes, and a total of 75.21% of repetitive DNA sequences. By leveraging HiFi reads, we mapped the genome-wide distribution of methylated bases (5mC and 6 mA). This comprehensive assembly offers a robust reference for morabine grasshoppers and supports further research into speciation and sex chromosome diversification within the group and its related species.

An expanded odorant-binding protein mediates host cue detection in the parasitic wasp Baryscapus dioryctriae basis of the chromosome-level genome assembly analysis.

BACKGROUND: Baryscapus dioryctriae (Chalcidodea: Eulophidae) is a parasitic wasp that parasitizes the pupae of many Pyralidae members and has been used as a biological control agent against Dioryctria pests of pinecones. RESULTS: This B. dioryctriae assembly has a genome size of 485.5 Mb with a contig N50 of 2.17 Mb, and scaffolds were assembled onto six chromosomes using Hi-C analysis, significantly increasing the scaffold N50 to 91.17 Mb, with more than 96.13% of the assembled bases located on chromosomes, and an analysis revealed that 94.73% of the BUSCO gene set. A total of 54.82% (279.27 Mb) of the assembly was composed of repetitive sequences and 24,778 protein-coding genes were identified. Comparative genomic analysis demonstrated that the chemosensory perception, genetic material synthesis, and immune response pathways were primarily enriched in the expanded genes. Moreover, the functional characteristics of an odorant-binding protein (BdioOBP45) with ovipositor-biased expression identified from the expanded olfactory gene families were investigated by the fluorescence competitive binding and RNAi assays, revealing that BdioOBP45 primarily binds to the D. abietella-induced volatile compounds, suggesting that this expanded OBP is likely involved in locating female wasp hosts and highlighting a direction for future research. CONCLUSIONS: Taken together, this work not only provides new genomic sequences for the Hymenoptera systematics, but also the high-quality chromosome-level genome of B. dioryctriae offers a valuable foundation for studying the molecular, evolutionary, and parasitic processes of parasitic wasps.

Satellitome Analysis of Adalia bipunctata (Coleoptera): Revealing Centromeric Turnover and Potential Chromosome Rearrangements in a Comparative Interspecific Study.

Eukaryotic genomes exhibit a dynamic interplay between single-copy sequences and repetitive DNA elements, with satellite DNA (satDNA) representing a substantial portion, mainly situated at telomeric and centromeric chromosomal regions. We utilized Illumina next-generation sequencing data from Adalia bipunctata to investigate its satellitome. Cytogenetic mapping via fluorescence in situ hybridization was performed for the most abundant satDNA families. In silico localization of satDNAs was carried out using the CHRISMAPP (Chromosome In Silico Mapping) pipeline on the high-fidelity chromosome-level assembly already available for this species, enabling a meticulous characterization and localization of multiple satDNA families. Additionally, we analyzed the conservation of the satellitome at an interspecific scale. Specifically, we employed the CHRISMAPP pipeline to map the satDNAs of A. bipunctata onto the genome of Adalia decempunctata, which has also been sequenced and assembled at the chromosome level. This analysis, along with the creation of a synteny map between the two species, suggests a rapid turnover of centromeric satDNA between these species and the potential occurrence of chromosomal rearrangements, despite the considerable conservation of their satellitomes. Specific satDNA families in the sex chromosomes of both species suggest a role in sex chromosome differentiation. Our interspecific comparative study can provide a significant advance in the understanding of the repeat genome organization and evolution in beetles.

The Chromosome-level Genome Provides Insights into the Evolution and Adaptation of Extreme Aggression.

Extremely aggressive behavior, as the special pattern, is rare in most species and characteristic as contestants severely injured or killed ending the combat. Current studies of extreme aggression are mainly from the perspectives of behavioral ecology and evolution, while lacked the aspects of molecular evolutionary biology. Here, a high-quality chromosome-level genome of the parasitoid Anastatus disparis was provided, in which the males exhibit extreme mate-competition aggression. The integrated multiomics analysis highlighted that neurotransmitter dopamine overexpression, energy metabolism (especially from lipid), and antibacterial activity are likely major aspects of evolutionary formation and adaptation for extreme aggression in A. disparis. Conclusively, our study provided new perspectives for molecular evolutionary studies of extreme aggression as well as a valuable genomic resource in Hymenoptera.

Chromosome-level genome assembly of Chinese water Scorpion Ranatra chinensis (Heteroptera: Nepidae).

Heteroptera (the true bugs), one of the most diverse lineages of insects, diversified in feeding strategies and living habitats, and thus become an ideal lineage for studies on adaptive evolution. Chinese water scorpion Ranatra chinensis (Heteroptera: Nepidae) is a predaceous bug living in lentic water systems, representing an ideal model for studying habitat transition and adaptation to water environment. However, genetic studies on this water bug remain limited. Here, we obtained a chromosome-level genome of R. chinensis using PacBio HiFi long reads and Hi-C sequencing reads. The total assembly size of genome is 867.89 Mb, with a scaffold N50 length of 26.48 Mb and the GC content of 39.50%. All contigs were assembled into 23 pseudo-chromosomes (N = 19 A + X1X2X3X4), and we predicted 18,424 protein-coding genes in this genome. This study will provide valuable genomic resources for future studies on the biology, water adaptation, and genome evolution of water bugs.

Fundamental Patterns of Structural Evolution Revealed by Chromosome-Length Genomes of Cactophilic Drosophila.

A thorough understanding of adaptation and speciation requires model organisms with both a history of ecological and phenotypic study as well as a complete set of genomic resources. In particular, high-quality genome assemblies of ecological model organisms are needed to assess the evolution of genome structure and its role in adaptation and speciation. Here, we generate new genomes of cactophilic Drosophila, a crucial model clade for understanding speciation and ecological adaptation in xeric environments. We generated chromosome-level genome assemblies and complete annotations for seven populations across Drosophila mojavensis, Drosophila arizonae, and Drosophila navojoa. We use these data first to establish the most robust phylogeny for this clade to date, and to assess patterns of molecular evolution across the phylogeny, showing concordance with a priori hypotheses regarding adaptive genes in this system. We then show that structural evolution occurs at constant rate across the phylogeny, varies by chromosome, and is correlated with molecular evolution. These results advance the understanding of the D. mojavensis clade by demonstrating core evolutionary genetic patterns and integrating those patterns to generate new gene-level hypotheses regarding adaptation. Our data are presented in a new public database (cactusflybase.arizona.edu), providing one of the most in-depth resources for the analysis of inter- and intraspecific evolutionary genomic data. Furthermore, we anticipate that the patterns of structural evolution identified here will serve as a baseline for future comparative studies to identify the factors that influence the evolution of genome structure across taxa.

The grasshopper genome reveals long-term gene content conservation of the X Chromosome and temporal variation in X Chromosome evolution.

We present the first chromosome-level genome assembly of the grasshopper, Locusta migratoria, one of the largest insect genomes. We use coverage differences between females (XX) and males (X0) to identify the X Chromosome gene content, and find that the X Chromosome shows both complete dosage compensation in somatic tissues and an underrepresentation of testis-expressed genes. X-linked gene content from L. migratoria is highly conserved across seven insect orders, namely Orthoptera, Odonata, Phasmatodea, Hemiptera, Neuroptera, Coleoptera, and Diptera, and the 800 Mb grasshopper X Chromosome is homologous to the fly ancestral X Chromosome despite 400 million years of divergence, suggesting either repeated origin of sex chromosomes with highly similar gene content, or long-term conservation of the X Chromosome. We use this broad conservation of the X Chromosome to test for temporal dynamics to Fast-X evolution, and find evidence of a recent burst evolution for new X-linked genes in contrast to slow evolution of X-conserved genes.

A chromosome-level genome assembly of the gall maker pest inquiline, Diomorus aiolomorphi Kamijo (Hymenoptera: Torymidae).

Diomorus aiolomorphi Kamijo (Hymenoptera: Torymidae) is an inquiline of gall maker Aiolomorphus rhopaloides Walker (Hymenoptera: Eurytomidae). They are of significant economic significance and predominantly inhabit bamboo forest. So far, only four scaffold-level genomes have been published for the family Torymidae. In this study, we present a high-quality genome assembly of D. aiolomorphi at the chromosome level, achieved through the integration of Nanopore (ONT) long-read, Illumina pair-end DNA short-read, and High-through Chromosome Conformation Capture (Hi-C) sequencing methods. The final assembly was 1,084.56 Mb in genome size, with 1,083.41 Mb (99.89%) assigned to five pseudochromosomes. The scaffold N50 length reached 224.87 Mb, and the complete Benchmarking Universal Single-Copy Orthologs (BUSCO) score was 97.3%. The genome contained 762.12 Mb of repetitive elements, accounting for 70.27% of the total genome size. A total of 18,011 protein-coding genes were predicted, with 17,829 genes being functionally annotated. The high-quality genome assembly of D. aiolomorphi presented in this study will serve as a valuable genomic resource for future research on parasitoid wasps. The results of this study may also contribute to the development of biological control strategies for pest management in bamboo forests, enhancing ecological balance and economic sustainability.

Chromosomal-level genome assembly of Hylurgus ligniperda: insights into host adaptation and environmental tolerance.

BACKGROUND: Hylurgus ligniperda (Coleoptera: Curculionidae) is a worldwide forest quarantine pest. It is widely distributed, has many host tree species, and possesses strong adaptability. To explore its environmental adaptability and the related molecular mechanisms, we conducted chromosome-level genome sequencing and analyzed the transcriptome under different environmental factors, identifying key expressed genes. RESULTS: We employed PacBio, Illumina, and Hi-C sequencing techniques to assemble a 520 Mb chromosomal-level genome of H. ligniperda, obtaining an N50 of 39.97 Mb across 138 scaffolds. A total of 10,765 protein-coding genes were annotated after repeat masking. Fourteen chromosomes were identified, among which Hyli14 was determined to be the sex chromosome. Survival statistics were tested over various growth periods under high temperature and low humidity conditions. The maximum survival period of adults reached 292 days at 25 °C, 65% relative humidity. In comparison, the maximum survival period was 14 days under 35 °C, 65% relative humidity, and 106 days under 25°C, 40% relative humidity. This indicated that environmental stress conditions significantly reduced adults' survival period. We further conducted transcriptome analysis to screen for potentially influential differentially expressed genes, such as CYP450 and Histone. Subsequently, we performed gene family analysis to gain insights into their functions and interactions, such as CYP450 and Histone. CYP450 genes affected the detoxification metabolism of enzymes in the Cytochrome P450 pathway to adapt to different environments. Histone genes are involved in insect hormone biosynthesis and longevity-regulating pathways in H. ligniperda to adapt to environmental stress. CONCLUSIONS: The genome at the chromosome level of H. ligniperda was assembled for the first time. The mortality of H. ligniperda increased significantly at 35 ℃, 65% RH, and 25 ℃, 40% RH. CYP450 and Histone genes played an important role in response to environmental stress. This genome offers a substantial genetic resource for investigating the molecular mechanisms behind beetle invasion and spread.

Homing gene drives can transfer rapidly between Anopheles gambiae strains with minimal carryover of flanking sequences.

CRISPR-Cas9 homing gene drives are designed to induce a targeted double-stranded DNA break at a wild type allele ('recipient'), which, when repaired by the host cell, is converted to the drive allele from the homologous ('donor') chromosome. Germline localisation of this process leads to super-Mendelian inheritance of the drive and the rapid spread of linked traits, offering a novel strategy for population control through the deliberate release of drive individuals. During the homology-based DNA repair, additional segments of the recipient chromosome may convert to match the donor, potentially impacting carrier fitness and strategy success. Using Anopheles gambiae strains with variations around the drive target site, here we assess the extent and nature of chromosomal conversion. We show both homing and meiotic drive contribute as mechanisms of inheritance bias. Additionally, over 80% of homing events resolve within 50 bp of the chromosomal break, enabling rapid gene drive transfer into locally-adapted genetic backgrounds.

A chromosomal-level genome assembly of Serrognathus titanus Boisduval, 1835 (Coleoptera: Lucanidae).

The Stag beetle (Coleoptera: Lucanidae) is a fascinating group, often considered one of the most primitive within the Scarabaeoidea. They are valuable models for studying beetle evolution. However, the lack of high-quality genomes hinders our understanding of the evolution and ecology of Lucanidae. In this study, we present a chromosome-level genome of Serrognathus titanus by combining PacBio HiFi long reads, Illumina short reads, and Hi-C data. The genome spans 384.07 Mb, with a scaffold N50 size of 75.81 Mb, and most contigs (97.45%, 374.30 Mb) were anchored into six chromosomes. Our BUSCO analysis of the assembly indicates a completeness of 97.6% (n = 1,367), with 92.8% single-copy BUSCOs and 4.8% duplicated BUSCOs identified. Additionally, we found that the genome contains 43.87% (168.50 Mb) repeat elements and identified 14,263 predicted protein-coding genes. The high-quality genome of S. titanus provides valuable genomic information for comprehending the evolution and ecology of Lucanidae.

The First FISH-Confirmed Non-Canonical Telomeric Motif in Heteroptera: Cimex lectularius Linnaeus, 1758 and C. hemipterus (Fabricius, 1803) (Hemiptera, Cimicidae) Have a 10 bp Motif (TTAGGGATGG)n.

Fluorescence in situ hybridization (FISH) with two different probes, the canonical insect telomeric sequence (TTAGG)n and the sequence (TTAGGGATGG)n, was performed on meiotic chromosomes of two members of the true bug family Cimicidae (Cimicomorpha), the common bed bug Cimex lectularius Linnaeus, 1758 and the tropical bed bug C. hemipterus (Fabricius, 1803), whose telomeric motifs were not known. In both species, there were no hybridization signals with the first probe, but strong signals at chromosomal ends were observed with the second probe, indicating the presence of a telomeric motif (TTAGGGATGG)n. This study represents the first FISH confirmation of the presence of a non-canonical telomeric motif not only for the infraorder Cimicomorpha but also for the suborder Heteroptera (Hemiptera) as a whole. The present finding is of key significance for unraveling the evolutionary shifts in the telomeric sequences in this suborder.

Chromosome-level genome assembly of marmalade hoverfly Episyrphus balteatus (Diptera: Syrphidae).

Episyrphus balteatus can provide dual ecosystem services including pest control and pollination, which the larvae are excellent predators of aphid pest whereas adults are efficient pollinator. In this study, we assembled a high-quality genome of E. balteatus from northern China geographical population at the chromosome level by using Illumina, PacBio long reads, and Hi-C technologies. The 467.42 Mb genome was obtained from 723 contigs, with a contig N50 of 9.16 Mb and Scaffold N50 of 118.85 Mb, and 90.25% (431.75 Mb) of the assembly was anchored to 4 pseudo-autosomes and one pseudo-heterosome. In total, 14,848 protein-coding genes were annotated, and 95.14% of genes were fully represented in NR, GO, KEGG databases. Besides, we also obtained the mitochondrial genome of E. balteatus of 16, 837 bp in length with 37 typical mitochondrial genes. Overall, this high-quality genome is valuable for evolutionary and genetic studies of E. balteatus and other Syrphidae hoverfly species.

Chromosome-level genome assembly from a single planthopper Nilaparvata muiri (Hemiptera: Delphacidae).

The planthopper Nilaparvata muiri is a sister species to N. lugens (Hemiptera: Delphacidae), a notorious insect pest in Asian rice fields. N. muiri and N. lugens have a different host preference despite the similarities in many biological features. To better understand the adaptive evolution of planthoppers, comprehensive genomic information on N. muiri and N. lugens are urgently needed. In this study, we used ultra-low input PacBio HiFi libraries and Hi-C sequencing technologies to assemble a reference genome of a single N. muiri at the chromosomal level. The genome size was determined to be 531.62 Mb with a contig N50 size of 2.47 Mb and scaffold N50 size of 38.37 Mb. Totally, 96.61% assembled sequences were anchored to the 15 pseudo-chromosomes. BUSCO analysis yielded an Insecta completeness score of 98.6%. A total of 22,057 protein-coding genes were annotated, and 168.16 Mb repetitive sequences occupying 31.63% of genome were pinpointed. The assembled genome is valuable for evolutionary and genetic studies of planthoppers, and may provide sights to pest control.

Two chromosome-level genome assemblies of galling aphids Slavum lentiscoides and Chaetogeoica ovagalla.

Slavum lentiscoides and Chaetogeoica ovagalla are two aphid species from the subtribe Fordina of Fordini within the subfamily Eriosomatinae, and they produce galls on their primary host plants Pistacia. We assembled chromosome-level genomes of these two species using Nanopore long-read sequencing and Hi-C technology. A 332 Mb genome assembly of S. lentiscoides with a scaffold N50 of 19.77 Mb, including 11,747 genes, and a 289 Mb genome assembly of C. ovagalla with a scaffold N50 of 11.85 Mb, containing 14,492 genes, were obtained. The Benchmarking Universal Single-Copy Orthologs (BUSCO) benchmark of the two genome assemblies reached 93.7% (91.9% single-copy) and 97.0% (95.3% single-copy), respectively. The high-quality genome assemblies in our study provide valuable resources for future genomic research of galling aphids.

A chromosome-level genome assembly of Prosopocoilus inquinatus Westwood, 1848 (Coleoptera: Lucanidae).

Lucanidae (Coleoptera: Scarabaeidae) are fascinating beetles exhibiting significant dimorphism and are widely used as beetle evolutionary study models. However, lacking high-quality genomes prohibits our understanding of Lucanidae. Herein, we proposed a chromosome-level genome assembly of a widespread species, Prosopocoilus inquinatus, combining PacBio HiFi, Illumina, and Hi-C data. The genome size reaches 649.73 Mb, having the scaffold N50 size of 59.50 Mb, and 99.6% (647.13 Mb) of the assembly successfully anchored on 12 chromosomes. The BUSCO analysis of the genome exhibits a completeness of 99.6% (n = 1,367), including 1,362 (98.5%) single-copy BUSCOs and 15 (1.1%) duplicated BUSCOs. The genome annotation identifies that the genome contains 61.41% repeat elements and 13,452 predicted protein-coding genes. This high-quality Lucanidae genome provides treasured genomic information to our knowledge of stag beetles.