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The genus Anastatus comprises a large group of parasitoids, including several biological control agents in agricultural and forest systems. The taxonomy and phylogeny of these species remain controversial. In this study, the mitogenome of A. fulloi Sheng and Wang was sequenced and characterized. The nearly full-length mitogenome of A. fulloi was 15,692 bp, compromising 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes and a control region (CR). The total A + T contents were 83.83%, 82.18%, 87.58%, 87.27%, and 82.13% in the whole mitogenome, 13 PCGs, 22 tRNA genes, 2 rRNA genes, and CR, respectively. The mitogenome presented negative AT skews and positive GC skews, except for the CR. Most PCGs were encoded on the heavy strand, started with ATN codons, and ended with TAA codons. Among the 3736 amino acid-encoding codons, TTA (Leu1), CGA (Arg), TCA (Ser2), and TCT (Ser2) were predominant. Most tRNAs had cloverleaf secondary structures, except trnS1, with the absence of a dihydrouridine (DHU) arm. Compared with mitogenomes of the ancestral insect and another parasitoid within Eupelmidae, large-scale rearrangements were found in the mitogenome of A. fulloi , especially inversions and inverse transpositions of tRNA genes. The gene arrangements of parasitoid mitogenomes within Chalcidoidea were variable. A novel gene arrangement was presented in the mitogenome of A. fulloi . Phylogenetic analyses based on the 13 protein-coding genes of 20 parasitoids indicated that the phylogenetic relationship of 6 superfamilies could be presented as Mymaridae + (Eupelmidae + (Encyrtidae + (Trichogrammatidae + (Pteromalidae + Eulophidae))). This study presents the first mitogenome of the Anastatus genus and offers insights into the identification, taxonomy, and phylogeny of these parasitoids.

In insects, the gustatory system has a critical function not only in selecting food and feeding behaviours but also in growth and metabolism. Gustatory receptors play an irreplaceable role in insect gustatory signalling. Trichogramma chilonis is an effective biocontrol agent against agricultural insect pests. However, the molecular mechanism of gustation in T. chilonis remains elusive. In this study, we found that T. chilonis adults had a preference for D-fructose and that D-fructose contributed to prolong longevity and improve fecundity. Then, We also isolated the full-length cDNA encoding candidate gustatory receptor (TchiGR43a) based on the transcriptome data of T. chilonis, and observed that the candidate gustatory receptor gene was expressed from the larval to adult stages. The expression levels of TchiGR43a were similar between female and male. A Xenopus oocyte expression system and two-electrode voltage-clamp recording further verified the function analysis of TchiGR43a. Electrophysiological results showed that TchiGR43a was exclusively tuned to D-fructose. By the studies of behaviour, molecular biology and electrophysiology in T. chilonis, our results lay a basic fundation of further study on the molecular mechanisms of gustatory reception and provide theoretical basis for the nutritional requirement of T. chilonis in biocontrol.

The gustatory system plays vital roles in food selection and feeding behaviours, as well as in other life activities in insects. In the process of taste perception, the functions of gustatory receptors are extremely important for insects. Trichogramma chilonis , a species of egg parasitoid, is often used as an effective biocontrol agent for agricultural and forestry pests. The utilization of T. chilonis has been well established, but the gustatory receptors, constituting the key factor in the molecular mechanism of gustation, are still unknown. In this study, we obtained two full-length cDNAs encoding putative sugar receptors ( TchiGR64f1 and TchiGR64f2 ), and the qRT-PCR results showed that TchiGR64f1 and TchiGR64f2 were expressed from the larval to adult stages. The expression of TchiGR64f1 and TchiGR64f2 differed between male and female adults. Functional analysis of TchiGR64f1 and TchiGR64f2 was conducted based on the Xenopus oocyte expression system and the two-electrode voltage-clamp system. The electrophysiological results showed that the combination of TchiGR64f1 + TchiGR64f2 was exclusively tuned to sucrose. Then, T. chilonis adults showed a preference for sucrose in a behavioural experiment. Additionally, sucrose consumption prolonged the lifespan and improved the fecundity of T. chilonis . These results not only enrich the reservoir of information on gustatory receptors in T. chilonis but also provide basic knowledge for further research on taste reception and for the development of a better strategy for the application of T. chilonis in biocontrol.

Trichogramma is a kind of egg parasitoid wasp that is widely used to control lepidopterous pests. Temperature is one of the main factors that determines the various life activities of this species, including development, reproduction and parasitism efficiency. Heat shock proteins (HSPs) are highly conserved and ubiquitous proteins that are best known for their responsiveness to temperature and other stresses. To explore the potential role of HSPs in Trichogramma species, we obtained the full-length cDNAs of six HSP genes (Tchsp10, Tchsp21.6, Tchsp60, Tchsp70, Tchsc70-3, and Tchsp90) from T. chilonis and analyzed their expression patterns during development and exposure to temperature stress. The deduced amino acid sequences of these HSP genes contained the typical signatures of their corresponding protein family and showed high homology to their counterparts in other species. The expression levels of Tchsp10, Tchsp21.6 and Tchsp60 decreased during development. However, the expression of Tchsc70-3 increased from the pupal stage to the adult stage. Tchsp70 and Tchsp90 exhibited the highest expression levels in the adult stage. The expression of six Tchsps was dramatically upregulated after 1 h of exposure to 32 and 40°C but did not significantly change after 1 h of exposure to 10 and 17°C. This result indicated that heat stress, rather than cold stress, induced the expression of HSP genes. Furthermore, the expression of these genes was time dependent, and the expression of each gene reached its peak after 1 h of heat exposure (40°C). Tchsp10 and Tchsp70 exhibited a low-intensity cold response after 4 and 8 h of exposure to 10°C, respectively, but the other genes did not respond to cold at any time points. These results suggested that HSPs may play different roles in the development of this organism and in its response to temperature stress.

Trichogramma is a useful species that is widely applied in biocontrol. Temperature profoundly affects the commercial application of T. chilonis. Different developmental transcriptomes of prepupae and pupae of T. chilonis under 10, 25, and 40°C were obtained from our previous study. In this study, transcriptomic analysis was further conducted to gain a clear understanding of the molecular changes in the prepupae of T. chilonis under different thermal conditions. A total of 37,295 unigenes were identified from 3 libraries of prepupae of T. chilonis, 17,293 of which were annotated. Differential expression analysis showed that 408 and 108 differentially expressed genes (DEGs) were identified after heat and cold treatment, respectively. Under heat stress, the pathway of protein processing in endoplasmic reticulum was found to be active. Most of the genes involved in this pathway were annotated as lethal (2) essential for life [l(2)efl] and heat shock protein genes (hsps), which were both highly upregulated. Nevertheless, most of the genes involved in another significantly enriched pathway of starch and sucrose metabolism were downregulated, including 1 alpha‐glucosidase gene and 2 beta‐glucuronidase genes. Under cold stress, no significantly enriched pathway was found, and the significantly enriched GO terms were related to the interaction with host and immune defenses. Together, these results provide us with a comprehensive view of the molecular mechanisms of T. chilonis in response to temperature stresses and will provide new insight into the mass rearing and utilization of T. chilonis. Transcriptomic responses to thermal stresses were characterized in prepupal Trichogramma chilonis. Two pathways were significantly enriched after heat treatment which may be important for heat tolerance in T. chilonis. A few DEGs were significantly enriched into GO terms related to interactions with host and immune defenses after cold treatment.

Spodoptera frugiperda damages crops around the world and has developed resistance to many pesticides. Beauveria bassiana, a fungus that is harmless to humans and the environment, is widely used in pest control. In our study, differentially expressed genes between S. frugiperda larvae, both exposed and unexposed, to B. bassiana were analyzed by transcriptome sequencing. More than 160 Gb of clean data were obtained, and 2767 and 2892 DEGs were identified in LH36vsCK36 and LH144vsCK144, respectively. To explore the roles of glycometabolism and antioxidation-related enzyme genes in S. frugiperda against B. bassiana infection, the expression patterns of those genes when under attack from B. bassiana were analyzed by quantitative real-time PCR. The results of enzyme activity experiments revealed that S. frugiperda larvae exposed to B. bassiana could upregulate these genes to produce more enzymes related to the maintainance of normal glucose metabolism, as well as regulate the expression of detoxification and antioxidant factors to enhance the larvae's detoxification and antioxidant capacity. The result implied that glycometabolism and antioxidation-related enzymes and genes played critical roles in the antifungal immune process of S. frugiperda larvae. This study enhances our understanding of the molecular mechanisms related to regulation of metabolism and provides a basis for exploring new methods to combat antifungal resistance in S. frugiperda.

The Chilo infuscatellus (Lepidoptera: Pyralidae) is a significant pest of sugarcane in China. The genome-level characteristics of this pest are important genetic resources for identification, phylogenetic analysis, and even management. In the present study, the complete mitogenome of C. infuscatellus was sequenced and characterized. The assembled mitochondrial genome is 15,252 bp in length and includes 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), 2 ribosomal RNA genes (rRNAs), and an A + T-rich region. Except for the CGA codon for the cox1 gene, the PCGs are initiated with ATN codons (ATG, ATT, and ATA). These PCGs are terminated with TAA or an incomplete termination codon of a single T. Except for the loss of the “DHU” arm for trnS1, the tRNA genes were folded into the typical cloverleaf structure. The A + T-rich region has a high AT content of 96.19% and contains the motifs “ATAGA” and “ATTTA”, as well as a 19 bp poly-T stretch and microsatellite regions. The C. infuscatellus mitogenome exhibits a conserved gene order among lepidopteran insects, with a rearrangement of the trnM gene compared to the ancestral insect gene order. Phylogenetic analysis based on the 13 PCGs using Bayesian inference (BI) and maximum likelihood (ML) methods confirmed the monophyly of Pyralidae and Crambidae within Pyraloidea. The relationships between subfamilies in Pyralidae can be described as (Galleriinae + (Phycitinae + (Pyralinae + Epipaschiinae))). The “PS clade” and “non‐PS clade” were formed within the family Crambidae. These findings provide valuable genetic resources for the identification, phylogenetic analysis, and management of sugarcane borers, contributing significantly to our understanding of the phylogeny of Pyraloidea insects and their evolution.

Spodoptera frugiperda damages crops around the world and has developed resistance to many pesticides. Beauveria bassiana, a fungus that is harmless to humans and the environment, is widely used in pest control. In our study, differentially expressed genes between S. frugiperda larvae, both exposed and unexposed, to B. bassiana were analyzed by transcriptome sequencing. More than 160 Gb of clean data were obtained, and 2767 and 2892 DEGs were identified in LH36vsCK36 and LH144vsCK144, respectively. To explore the roles of glycometabolism and antioxidation-related enzyme genes in S. frugiperda against B. bassiana infection, the expression patterns of those genes when under attack from B. bassiana were analyzed by quantitative real-time PCR. The results of enzyme activity experiments revealed that S. frugiperda larvae exposed to B. bassiana could upregulate these genes to produce more enzymes related to the maintainance of normal glucose metabolism, as well as regulate the expression of detoxification and antioxidant factors to enhance the larvae's detoxification and antioxidant capacity. The result implied that glycometabolism and antioxidation-related enzymes and genes played critical roles in the antifungal immune process of S. frugiperda larvae. This study enhances our understanding of the molecular mechanisms related to regulation of metabolism and provides a basis for exploring new methods to combat antifungal resistance in S. frugiperda.

Anagrus nilaparvatae is an important egg parasitoid wasp of pests such as the rice planthopper. Based on the powerful olfactory system of sensing chemical information in nature, A. nilaparvatae shows complicated life activities and behaviors, such as feeding, mating, and hosting. We constructed a full‐length transcriptome library and used this to identify the characteristics of soluble chemical communication proteins. Through full‐length transcriptome sequencing, splicing, assembly, and data correction by Illumina, we obtained 163.59 Mb of transcriptome data and 501,179 items with annotation information. We then performed Gene Ontology (GO) functional classification of the transcriptome's unigenes. We analyzed the sequence characteristics of soluble chemical communication protein genes and identified eight genes: AnilOBP2, AnilOBP9, AnilOBP23, AnilOBP56, AnilOBP83, AnilCSP5, AnilCSP6, and AnilNPC2. After sequence alignment and conserved domain prediction, the eight proteins encoded by the eight genes above were found to be consistent with the typical characteristics of odorant‐binding proteins (OBPs), chemosensory proteins (CSPs), and Niemann‐pick type C2 proteins (NPC2s) in other insects. Phylogenetic tree analysis showed that the eight genes share low homology with other species of Hymenoptera. Quantitative real‐time polymerase chain reaction (RT‐qPCR) was used to analyze the expression responses of the eight genes in different sexes and upon stimulation by volatile organic compounds. The relative expression levels of AnilOBP9, AnilOBP26, AnilOBP83, AnilCSP5, and AnilNPC2 in males were significantly higher than those in females, while the relative expression level of AnilCSP6 was higher in females. The expression levels of AnilOBP9 and AnilCSP6 were significantly altered by the stimulation of β‐caryophyllene, suggesting that these two genes may be related to host detection. This study provides the first data for A. nilaparvatae's transcriptome and the molecular characteristics of soluble chemical communication proteins, as well as an opportunity for understanding how A. nilaparvatae behaviors are mediated via soluble chemical communication proteins. The structure predicted of 5 AnilOBPs and 2 AnilCSPs are spherical structures formed by α‐helices, and AnilNPC2 are spherical structures formed by β‐folded.

FOXL2 (forkhead box protein L2) is a transcription factor, its function and regulatory mechanism have been mainly studied in mammals; related research on marine invertebrates is still insufficient. It was found that oogenesis was affected, and even a small number of cells resembling spermatogonial morphology appeared in C. farreri ovaries after the FOXL2 was knocked down through RNA interference (RNAi) technology in our laboratory previously. Based on previous research, this paper conducted transcriptome sequencing and differential expression analysis on the ovarian tissues between the experimental group (post-RNAi) and the control group (pre-RNAi) of C. farreri, and used recombinant C. farreri FOXL2 protein for antibody production in Chromatin Immunoprecipitation Sequencing (ChIP seq) experiments to comprehensively analyze the pathways and key genes regulated by FOXL2 during oogenesis. The results showed that in the RNAi experimental group, 389 genes were upregulated, and 1615 genes were downregulated. Among the differentially expressed genes (DEGs), the differential genes related to gender or gonadal development are relatively concentrated in physiological processes such as steroid hormone synthesis, spermatogenesis, gonadal development, and ovarian function maintenance, as well as the FoxO and estrogen signaling pathways. Combining transcriptome and ChIP-seq data, it was found that there were some genes related to sex gonadal development among genes which were directly regulated by FOXL2, such as Wnt4, SIRT1, HSD17B8, GABABR1, KRAS, NOTCH1, HSD11B1, cPLA2, ADCY9, IP3R1, PLCB4, and Wnt1. This study lays the foundation for a deeper understanding of the FOXL2′s specific regulatory mechanism during oogenesis in scallops as a transcription factor.