Archives of Insect Biochemistry and Physiology最新文献

Rhynchophorus ferrugineus (Olivier, 1790) (Coleoptera: Dryophthoridae), commonly known as the red palm weevil (RPW), is a globally significant pest that threatens economically important palm trees. Its cryptic infestation behavior leads to irreversible damage and eventual host plant death. Current control methods using broad-spectrum insecticides are largely ineffective due to resistance development and their adverse effects on nontarget organisms, necessitating novel strategies. This study integrates proteomics and transcriptomics data to explore the molecular landscape of RPW and identify pathways for targeted pest management. A total of 16,954 transcripts and 983 proteins were identified across three developmental stages (larvae, male adults, and female adults), with a notable decline in protein numbers from larvae to adult. Differential expression analysis revealed 7540 proteins varying significantly between developmental stages. Through subtractive analysis, 218 proteins meeting stringent inclusion and exclusion criteria were identified. These proteins underwent pathway enrichment analysis, mapping to 39 enriched pathways (p-value and an FDR of < 0.01). Among these, two pathways involving three key enzymes were highlighted as high-potential targets for developing insect-specific insecticides and diet-specific control strategies. This is the first comprehensive proteomics study analyzing the whole body of RPW across its developmental stages. The findings emphasize critical pathways, their enzyme components, and the regulation of these enzymes, offering novel insights for sustainable and targeted pest management solutions.

Japanese pine sawyer beetle (JPSB), Monochamus alternatus is a forest insect pest with damaging to pine trees through vectoring plant-parasitic nematodes. In our previous work, the entomopathogenic Metarhizium anisopliae JEF-197 was effective in controlling JPSB adults. However some of JPSB adults survived well even against the fungal treatment. Now here in this work, we analyzed the transcriptome of JEF-197 from the fungus-treated JPSB adults which still survived in 8 days after the treatment. The day was determined based on the lethal time 50 (LT₅₀) in our previous study. As a control, JEF-197 was cultured on 1/4SDA for 8 days. The plate-cultured JEF-197 transcripts were used for building-up an index in the abundance analysis using kallisto to investigate the gene regulation. Additionally, transcripts from the JEF-197-treated PSB were analyzed to find possible fungal transcripts to enlarge the index of abundance analysis. In the following differentially expressed gene (DEG) analysis, most JEF-197 transcripts showed significant down-regulations in JPSB adults 8 days after treatment, which were presented as clustering heatmap, PCA, MA and Volcano plots. The GO enrichment analysis showed similar results, in which most of pathways were significantly suppressed. Metabolic and biosynthesis metabolisms were most dominantly downregulated pathways. Particularly, many genes of glucose metabolisms were significantly suppressed, including genes for glycolysis, TCA, ATP & nucleotide synthesis, and glycogen & chitin production. This work suggests that JEF-197 lost its own glucose metabolism in the survived JPSB adults, and the survival could be involved in the active and continuous host defense mechanisms. It gives us questions what factors would be involved in the different response of individual to the fungal treatment and what happens if live and dead hosts were pooled in RNA-sequencing.

The primary vector of the West Nile virus, Culex pipiens, undergoes reproductive dormancy during the adverse winter season. While our current understanding has mainly focused on cellular signals and phenotypic shifts occurring at a global scale during diapause, information on tissue-specific transcriptomic changes remains limited. This knowledge gap is a major challenge in interpreting the regulatory mechanisms at the tissue level. To address this, the present work utilized RNA-seq technology to investigate the transcriptional changes in the head that house the brain and crucial endocrinal organs such as corpora allata. We obtained RNA samples from the heads of diapausing and nondiapausing female mosquitoes at two specific time intervals, ZT0 and ZT16, and then subjected them to sequencing. Our results revealed differences in differentially expressed genes between diapause and non-diapause at ZT0 and ZT16, highlighting the phenotypic and diel variations in gene expression. We also selected twelve genes associated with the diapause phenotype and examined the transcript abundance at six different time points over 24 h. qRT-PCR analysis showed similar up- and downregulation of transcripts between the diapause and nondiapause phenotypes thus validating the results of RNA-seq. In summary, our study identified new genes with phenotypic and diel differentiation in their expression, potentially linking photoperiod to seasonal reproductive dormancy in insects. The newly presented information will significantly advance our understanding of head-specific genes crucial for insect diapause.

Cyclaniliprole, a type of the third-generation anthranilic diamide insecticide, was mainly used for management of various pests. Myzus persicae (Hemiptera: Aphididae), known as the peach-potato aphid, is an economically essential pest with worldwide distribution. However, the risk assessment of cyclaniliprole in M. persicae is unclear. The cyclaniliprole risk assessment in M. persicae showed 2.56-fold resistance to cyclaniliprole after 26 generation selection in comparison to the initial susceptible population. The cross-resistance experiment revealed that the low cross-resistance to imidacloprid (4.2-fold) in the cyclaniliprole-selected strain was observed when comparing to the susceptible population. Realized heritability (h²) of cyclaniliprole resistance was 0.0362. When mean slope = 2.217 and h² = 0.0362, then 31–69 generations would be required for an increase of LC₅₀s with ten times at 90%–50% selection intensity. The fecundity (the number of offspring per female) of the cyclaniliprole-selected strain had no significant difference with the susceptible population. The mRNA expression of the target gene ryanodine receptor was significantly enhanced in the cyclaniliprole-selected strain. The absence of fitness costs, the minimal resistance risk, and very low levels of cross-resistance in the cyclaniliprole-selected strain provide strong support for designing the effective management strategies against M. persicae.

The activin cascade is activated when a pair of extracellular ligand (Myoglianin, Myo; Activin β, Actβ; Dawdle, Daw) binds to two pairs of transforming growth factor β (TGF) serine-threonine receptor kinases, TGF-β type I (Baboon, Babo) and II receptors. However, the roles of activin way have not well been explored in non-Drosophilid insects. In the present paper, we compared the functions of Activin β (Actβ) ligand and receptor isoform BaboB in post-embryonic development in a defoliating ladybird Henosepilachna vigintioctopunctata. RNA interference (RNAi) for Hvactβ but not Hvbabob upregulated juvenile hormone signal, reduced ecdysone pathway and impaired larval-pupal transformation. The arresting Hvactβ RNAi larvae formed pupa-specific black markings below the larval exuviae. Thus, the impairment of metamorphosis may be caused by failing to complete ecdysis behavior due to nonfunctional muscles. Consistently, larval body sizes were smaller and adult appendages were shorter in the Hvactβ RNAi larvae, in contrast to those in the Hvbabob depleted beetles. Conversely, knockdown of Hvbabob but not Hvactβ changed the pigmentation of adult elytra. Our results suggest that Actβ exerts regulative roles in JH production, ecdysteroidogenesis and organ remodeling, thus contributing to modulate the larva-pupa-adult transformation, through a BaboB independent way in H. vigintioctopunctata.

RNA interference (RNAi) technology is widely used in gene functional studies and has been shown to be a promising next generation alternative for insect pest management. To understand the efficiency of RNAi machinery in Leucinodes orbonalis (L. orbonalis) Guenee, a destructive pest of eggplant, core RNAi pathway genes Argonaute-2, Dicer-2, Loquacious, and Sid-1 were mined from the transcriptome and characterized. The transcript abundance of these genes was studied after exposure to exogenous double-stranded RNA (dsRNA). Domain structure analysis revealed that these genes have conserved domains required for the definite protein function in the siRNA pathway. The protein sequences when subjected to phylogenetic analysis showed a close relation with homologs obtained from Ostrinia sp. The insects fed with dsRNA designed for vacuolar sorting protein SNF7 gene showed significant downregulation at 48 h post treatment and about 79% larval mortality. The expression study of genes showed a significant spike in transcript abundance of Dicer-2, Argonatute-2, and downregulation of Loquacious at 24 and 48 h post dsRNA exposure. The results on siRNA machinery genes expression and target gene knockdown implies L. orbonalis has an ample response to exogenous dsRNA.

Zinc homeostasis contributes significantly to numerous physiological processes. Drosophila ZnT35C protein, a zinc transporter encoded by CG3994, is chiefly located on the cell membrane and facilitates the transport of zinc from the cytoplasm to the extracellular space to sustain zinc homeostasis within the organism. Previous studies about ZnT35C have involved diverse structures such as the Malpighian tubules, adult brain, and sensory nervous system. Nonetheless, the role of ZnT35C in Drosophila spermatogenesis remained unclear. In our study, we discovered that ZnT35C plays a pivotal role in Drosophila spermatogenesis. Its knockdown resulted in sperm loss and male infertility. When ZnT35C was knocked down in cyst cells, zinc was concentrated within cyst cells, inhibiting the proper development of germ cells and thereby causing the incapacity of flies to generate mature sperms. Zinc supplementation can effectively rescue this failure of spermatogenesis. Our research outcomes suggest that ZnT35C, through modulating the zinc environment within the testes, impacts the male fertility of Drosophila, occupying a crucial position in the spermatogenesis process.