摘要: MicroRNAs play critical roles in multiple developmental processes in insects. Our previous study showed that CRISPR/Cas9-mediated knock down of the microRNA let-7 in silkworms increased the size of larvae and silk glands, thereby improving the silk production capacity. In this study, we elucidate the molecular mechanism underlying of let-7 regulates growth. Identification of differentially expressed genes in response to let-7 knock down revealed enrichment of pathways associated with cell proliferation and DNA replication. let-7 dysregulation affected the cell cycle and proliferation of the Bombyx mori cell line BmN. Dual-luciferase and target site mutation assays showed that BmCDK1 is a direct target gene of let-7, with only 1 binding site on its 3 '-untranslated region. RNA interference of BmCDK1 inhibited cell proliferation, but this effect was counteracted by co-transfection with let-7 antagomir. Moreover, let-7 knock down induced BmCDK1 expression and promoted cell proliferation in multiple tissues, and further induced endomitosis in the silk gland in vivo. Knock down of BmCDK1 resulted in abnormal formation of a new epidermis, and larval development was arrested at the 2nd or 3rd molt stage. Taken together, our results demonstrated that BmCDK1 is a novel target of let-7 in cell fate determination, possessing potential for improving silk yield in silkworm.

摘要: Panonychus citri McGregor (Acari: Tetranychidae), a destructive citrus pest, causes considerable annual economic losses due to its short lifespan and rapid resistance development. MicroRNA (miRNA)-induced RNA interference is a promising approach for pest control because of endogenous regulation of pest growth and development. To search for miRNAs with potential insecticidal activity in P. citri, genome-wide analysis of miRNAs at different developmental stages was conducted, resulting in the identification of 136 miRNAs, including 73 known and 63 novel miRNAs. A total of 17 isomiRNAs and 12 duplicated miRNAs were characterized. MiR-1 and miR-252-5p were identified as reference miRNAs for P. citri and Tetranychus urticae. Based on differential expression analysis, treatments with miR-let-7a and miR-315 mimics and the miR-let-7a antagomir significantly reduced the egg hatch rate and resulted in abnormal egg development. Overexpression or downregulation of miR-34-5p and miR-305-5p through feeding significantly decreased the adult eclosion rate and caused molting defects. The 4 miRNAs, miR-let-7a, miR-315, miR-34-5p, and miR-305-5p, had important regulatory functions and insecticidal properties in egg hatching and adult eclosion. In general, these data advance our understanding of miRNAs in mite biology, which can assist future studies on insect-specific miRNA-based green pest control technology.

摘要: Successful completion of spermatogenesis is crucial for the perpetuation of the species. In Drosophila, spermatid individualization, a process involving changes in mitochondrial structure and function is critical to produce functional mature sperm. Ant2, encoding a mitochondrial adenine nucleotide translocase, is highly expressed in male testes and plays a role in energy metabolism in the mitochondria. However, its molecular function remains unclear. Here, we identified an important role of Ant2 in spermatid individualization. In Ant2 knockdown testes, spermatid individualization complexes composed of F-actin cones exhibited a diffuse distribution, and mature sperms were absent in the seminal vesicle, thus leading to male sterility. The most striking effects in Ant2-knockdown spermatids were decrease in tubulin polyglycylation and disruption of proper mitochondria derivatives function. Excessive apoptotic cells were also observed in Ant2-knockdown testes. To further investigate the phenotype of Ant2 knockdown in testes at the molecular level, complementary transcriptome and proteome analyses were performed. At the mRNA level, 868 differentially expressed genes were identified, of which 229 genes were upregulated and 639 were downregulated induced via Ant2 knockdown. iTRAQ-labeling proteome analysis revealed 350 differentially expressed proteins, of which 117 proteins were upregulated and 233 were downregulated. The expression of glutathione transferase (GstD5, GstE5, GstE8, and GstD3), proteins involved in reproduction were significantly regulated at both the mRNA and protein levels. These results indicate that Ant2 is crucial for spermatid maturation by affecting mitochondrial morphogenesis.

摘要: Body color polyphenism is common in Diaphorina citri. Previous studies compared physiological characteristics in D. citri, but the ecological and biological sig-nificance of its body color polyphenism remains poorly understood. We studied the eco-logical and molecular effects of stressors related to body color in D. citri. Crowding or low temperature induced a high proportion of gray morphs, which had smaller bodies, lower body weight, and greater susceptibility to the insecticide dinotefuran. We performed transcriptomic and metabolomics analysiis of 2 color morphs in D. citri. Gene expression dynamics revealed that the differentially expressed genes were predominantly involved in energy metabolism, including fatty acid metabolism, amino acid metabolism, and car-bohydrate metabolism. Among these genes, plexin, glycosidase, phospholipase, take out, trypsin, and triacylglycerol lipase were differentially expressed in 2 color morphs, and 6 hsps (3 hsp70, hsp83, hsp90, hsp68) were upregulated in gray morphs. The metabolome data showed that blue morphs exhibited a higher abundance of fatty acid and amino acid, whereas the content of carbohydrates was elevated in gray morphs. This study partly ex-plains the body color polyphenism of D. citri and provides insights into the molecular changes of stress response of D. citri.

摘要: Mosquito-borne viruses (MBVs) are a large class of viruses transmitted mainly through mosquito bites, including dengue virus, Zika virus, Japanese encephalitis virus, West Nile virus, and chikungunya virus, which pose a major threat to the health of people around the world. With global warming and extended human activities, the incidence of many MBVs has increased significantly. Mosquito saliva contains a variety of bioactive protein components. These not only enable blood feeding but also play a crucial role in regulating local infection at the bite site and the remote dissemination of MBVs as well as in remodeling the innate and adaptive immune responses of host vertebrates. Here, we review the physiological functions of mosquito salivary proteins (MSPs) in detail, the influence and the underlying mechanism of MSPs on the transmission of MBVs, and the current progress and issues that urgently need to be addressed in the research and development of MSP-based MBV transmission blocking vaccines.