College of Life Sciences, Gannan Normal University, Ganzhou, China.
National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China.
Pest Manag Sci. 2024 Dec;80(12):6262-6275. doi: 10.1002/ps.8355. Epub 2024 Aug 2.
The insect cuticle consists of chitin fibers and a protein matrix, which plays an important role in protecting the body from invasion of various pathogens and prevents water loss. Periodic synthesis and degradation of the cuticle is required for the growth and development of insects. Key genes involved in cuticle formation have long been considered a potential target for pest control.
In this study, a member of the RR-2 subfamily of cuticular protein 8 (DcCP8) was identified from the Diaphorina citri genome database. Immunofluorescence analysis suggested that DcCP8 was mainly located in the Diaphorina citri exocuticle and can be induced to up-regulate 12 h following 20-hydroxyecdysone (20E) treatment. Silencing of DcCP8 by RNA interference (RNAi) significantly disrupted the metamorphosis to the adult stage, and improved the permeability of the cuticle. Transmission electron microscopy (TEM) analysis revealed that the synthesis of the exocuticle was impressed after silencing of DcCP8. Furthermore, the recombinant DcCP8 protein exhibited chitin-binding properties in vitro, down-regulation of DcCP8 significantly inhibited expression levels of chitin metabolism-related genes. Additionally, a sprayable RNAi method targeting DcCP8 based on star polycation (SPc) nanoparticles-wrapped double-stranded RNA (dsRNA) significantly increased Diaphorina citri mortality. Transcriptome sequencing further confirmed that genes associated with the endocytic pathway and immune response were up-regulated in Diaphorina citri after SPc treatment.
The current study indicated that DcCP8 is critical for the formation of Diaphorina citri exocuticles, and lays a foundation for Diaphorina citri control based on large-scale dsRNA nanoparticles. © 2024 Society of Chemical Industry.
昆虫的外骨骼由几丁质纤维和蛋白质基质组成，它在外骨骼的形成过程中起着重要的作用，对于保护机体免受各种病原体的侵袭和防止水分流失至关重要。昆虫的生长和发育需要周期性地合成和降解外骨骼。长期以来，参与外骨骼形成的关键基因一直被认为是害虫防治的潜在靶标。
本研究从柑橘木虱基因组数据库中鉴定出一种角质蛋白 8（DcCP8）的 RR-2 亚家族成员。免疫荧光分析表明，DcCP8 主要位于柑橘木虱的外表皮，在 20-羟基蜕皮酮（20E）处理 12 小时后可被诱导上调。DcCP8 的 RNA 干扰（RNAi）沉默显著破坏了向成虫阶段的变态，并且改善了外骨骼的通透性。透射电子显微镜（TEM）分析显示，沉默 DcCP8 后，外表皮的合成受到影响。此外，重组 DcCP8 蛋白在体外表现出与几丁质结合的特性，下调 DcCP8 显著抑制了几丁质代谢相关基因的表达水平。此外，基于星型聚阳离子（SPc）纳米颗粒包裹双链 RNA（dsRNA）的靶向 DcCP8 的喷雾 RNAi 方法显著增加了柑橘木虱的死亡率。转录组测序进一步证实，SPc 处理后，与内吞途径和免疫反应相关的基因在柑橘木虱中上调。
本研究表明 DcCP8 对柑橘木虱外表皮的形成至关重要，为基于大规模 dsRNA 纳米颗粒的柑橘木虱防治奠定了基础。
