Archives of Insect Biochemistry and Physiology最新文献

Although muscle development has been widely studied in Drosophila melanogaster, it was a great challenge to apply to developmental processes of other insect muscles. This study was focused on the functional characterization of a basic helix-loop-helix transcription factor gene twist in an herbivorous ladybird Henosepilachna vigintioctopunctata. Its transcript (Hvtwist) levels were detected in all developmental stages. RNA interference (RNAi)-aided knockdown of Hvtwist at the penultimate larval instar stage impaired pupation, and caused a deformed adult in the legs. The tarsi were malformed and did not support the bodies in an upright position. The climbing ability was impaired. Moreover, around 50% of the impaired adults had a malformed elytrum. In addition, they consumed less foliage and did not lay eggs. A hematoxylin–eosin staining of the leg demonstrated that the tibial extensor (TE) and the tibial flexor (TF) muscles were originated from the femurs while levator and depressor muscles of the tarsus (TL and TD) were located in the tibia in the control adults, in which tarsal segments were devoid of muscles. RNAi treatment specific to Hvtwist expression markedly impaired TE and TF muscles in the femurs, and prevented the development of TL and TD muscles in the tibia. Therefore, our findings demonstrate Twist plays a vital role in the myogenesis in H. vigintioctopunctata adult legs.

Mitochondria are essential organelles for maintaining vital cellular functions, and microRNAs (miRNAs) regulate gene expression posttranscriptionally. miRNAs exhibit tissue and time-specific patterns in mitochondria and specifically mitochondrial miRNAs (mitomiRs) can regulate the mRNA expression both originating from mitochondrial and nuclear transcription which affect mitochondrial metabolic activity and cell homeostasis. In this study, miRNAs of two insect species, Syrista parreyssi (Hymenoptera) and Lepisma saccharina (Zygentoma), were investigated for the first time. The known and possible novel miRNAs were predicted and characterized and their potential effects on mitochondrial transcription were investigated in these insect species using deep sequencing. The previously reported mitomiRs were also investigated and housekeeping miRNAs were characterized. miRNAs that are involved in mitochondrial processes such as apoptosis and signaling and that affect genes encoding the subunits of OXPHOS complexes have been identified in each species. Here, 81 and 161 novel mature miRNA candidates were bioinformatically predicted and 9 and 24 of those were aligned with reference mitogenomes of S. parreyssi and L. saccharina, respectively. As a result of RNAHybrid analysis, 51 and 69 potential targets of miRNAs were found in the mitogenome of S. parreyssi and L. saccharina, respectively. cox1 gene was the most targeted gene and cytB, rrnS, and rrnL genes were highly targeted in both of the species by novel miRNAs, hypothetically. We speculate that these novel miRNAs, originating from or targeting mitochondria, influence on rRNA genes or positively selected mitochondrial protein-coding genes. These findings may provide a new perspective in evaluating miRNAs for maintaining mitochondrial function and transcription.

The click-beetles (Elateridae) are a species-rich beetle family that is easily recognizable. They are distributed in all zoogeographical regions with over 11,000 species. Comparative studies of the structural characteristics of mitochondrial genomes (mitogenomes), as well as phylogenetic relationships of click-beetles, can improve our understanding of mitogenomic evolution. In this study, we determined four mitogenomes from Elateridae by next-generation sequencing. The four mitogenomes were 16,005 to 16,930 bp in length with 37 typical genes and a control region (A + T-rich region). Combined with previously reported elaterid mitogenomes, all PCGs initiate with either the standard start codon of ATN or TTG. According to the nonsynonymous/synonymous mutation ratio (Ka/Ks) of all PCGs, the highest and the lowest evolutionary rates were found for atp8 and cox1, respectively. Among the control regions of the four mitogenomes, several different patterns and numbers of tandem repeats were identified, which was the primary cause of the length variation in control regions. Phylogenetic analyses were conducted based on 13 protein-coding genes and two ribosomal RNA genes from 33 species of Elateridae and two outgroups. The Bayesian inference and maximum likelihood trees had an identical topological structure. The monophyly of Cardiophorinae, Agrypninae and Elaterinae was recovered with high support in all topologies, and the Tetralobinae was placed as the earliest branch in the Elateridae. Expanding the availability of mitogenomic and genomic data from a broader range of click-beetles could provide more clarity on the disputed relationships among subfamilies within Elateridae.

South American tomato leafminer, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae), is native to South America, but is a major invasive and quarantine pest species in Europe, Africa, and Asia. It causes extensive damage of up to 100% yield loss in tomatoes (Solanum lycopersicum) in open and greenhouse conditions. Since its first invasion in Spain in 2006, it has spread rapidly into many countries in the Mediterranean and Western Europe and further invaded Africa and Asia. In Asia, it was first recorded in August 2009 in Turkey and spread to most South and East Asian countries. In this study, we reviewed existing work on the biology and distribution of T. absoluta in Asia, as well as the damage it causes. This review will help to develop efficient management tactics as well as establish quarantine and phytosanitary precautions in uninvaded countries.

Melon fly, Zeugodacus cucurbitae (Coquillett) is a major pest of cucurbitaceous crops, and causes substantial yield losses and economic costs. CRISPR/Cas9 is a rapid and effective site-specific genome editing tool for the generation of genetic changes that are stable and heritable. The CRISPR/Cas9 tool uses synthetically designed single guide RNA (sgRNA) that is complementary to the target gene and guides the Cas9 enzyme to perform nuclease activity by making double-strand breaks in the target DNA sequences. This tool can be effectively exploited to improve traits critical for the management of insect pests by targeting specific genes encoding these traits without the need of extensive genetic information. The white gene is an important gene responsible for the transport of body pigment precursor molecules. In this study, we produced effective mutagenesis of the white gene of Z. cucurbitae using the CRISPR/Cas9 tool with double sgRNA to target multiple sites of white to increase the efficiency in the generation of frame-shift mutations resulting in the white eye phenotype in adults. This was achieved through embryonic microinjection of the ribonucleoprotein (RNP) complex in the pre-blastoderm embryo stage 1 h after embryo laying. Our success with the production of a white eye mutant fly by CRISPR/Cas9 mutagenesis is important for the research on gene function and protein-level modifications in melon fly and forms the basis for the development of new genetic control strategies such as precision guided sterile insect technique (pgSIT) for this pest of economic significance.

Insecticide resistance poses a significant challenge, diminishing the effectiveness of chemical insecticides. To address this global concern, the development of novel and efficient pest management technologies based on chemical insecticides is an ongoing necessity. The insect cuticle, a highly complex and continuously renewing organ, plays a crucial role in this context. On one hand, as the most vital structure, it serves as a suitable target for insecticides. On the other hand, it acts as the outermost barrier, isolating the insect's inner organs from the environment, and thus offering resistance to contact with insecticides, preventing their entry into insect bodies. Our work focuses on key targets concerning cuticle formation and the interaction between the cuticle and contact insecticides. Deeper studying insect cuticles and understanding their structure–function relationship, formation process, and regulatory mechanisms during cuticle development, as well as investigating insecticide resistance related to the barrier properties of insect cuticles, are promising strategies not only for developing novel insecticides but also for discovering general synergists for contact insecticides. With this comprehensive review, we hope to contribute valuable insights into the development of effective pest management solutions and the mitigation of insecticide resistance.

Paranosema locustae is an entomopathogenic microsporidia with promising potential for controlling agricultural pests, including Locusta migratoria manilensis. However, it has the disadvantage of having a slow insecticidal rate, and how P. locustae infection impacts the host immune response is currently unknown. The present study investigated the effect of P. locustae on the natural immune response of L. migratoria and the activities of enzymes that protect against oxidative stress. Infection with P. locustae increased the hemocytes and nodulation number of L. migratoria at the initial stage of infection. The hemocyte-mediated modulation of immune response was also affected by a decrease in the number of hemocytes 12 days postinfection. Superoxide dismutase activity in locusts increased in the early stages of infection but decreased in the later stages, whereas the activities of peroxidase (POD) and catalase (CAT) showed opposite trends may be due to their different mechanisms of action. Furthermore, the transcription levels of mRNA of antimicrobial peptide-related genes and phenoloxidase activity in hemolymph in L. migratoria were suppressed within 15 days of P. locustae infection. Overall, our data suggest that P. locustae create a conducive environment for its own proliferation in the host by disrupting the immune defense against it. These findings provide useful information for the potential application of P. locustae as a biocontrol agent.

Signaling pathways regulate the transmission of signals during organism growth and development, promoting the smooth and accurate completion of numerous physiological and biochemical reactions. The extracellular signal-regulated kinase (ERK) signaling pathway is an essential pathway involved in regulating various physiological processes, such as cell proliferation, differentiation, adhesion, migration, and more. This pathway also contributes to several important physiological processes in silkworms, including protein synthesis, reproduction, and immune defense against pathogens. Organizing related studies on the ERK signaling pathway in silkworms can provide a better understanding of its mechanism in Lepidopterans and develop a theoretical foundation for improving cocoon production and new strategies for pest biological control.

Infection of intestinal tissues with Wolbachia has been found in Habrobracon hebetor. There are not many studies on the relationship between Habrobracon and Wolbachia, and they focus predominantly on the sex index of an infected parasitoid, its fertility, and behavior. The actual role of Wolbachia in the biology of Habrobracon is not yet clear. The method of complete eradication of Wolbachia in the parasitoid was developed here, and effects of the endosymbiont on the host's digestive metabolism were compared between two lines of the parasitoid (Wolbachia-positive and Wolbachia-negative). In the gut of Wolbachia⁺ larvae, lipases' activity was higher almost twofold, and activities of acid proteases, esterases, and trehalase were 1.5-fold greater than those in the Wolbachia^– line. Analyses of larval homogenates revealed that Wolbachia⁺ larvae accumulate significantly more lipids and have a lower amount of pyruvate as compared to Wolbachia^– larvae. The presented results indicate significant effects of the intracellular symbiotic bacterium Wolbachia on the metabolism of H. hebetor larvae and on the activity of its digestive enzymes.