Abstract：
Insect chitinases (Chts) play a crucial role in the molting process, enabling continuous growth through sequential developmental stages. Based on their high homology to insect Chts, TuCht1 (group II), TuCht4 (group I) and TuCht10 (group IV) were identified, and their roles during molting process were investigated. TuCht1 was mainly expressed in the deutonymphal stage, while TuCht4 was mainly expressed in the nymphal stage and the highest expression level of TuCht10 was observed in the larvae. Feeding RNAi assays have shown that group I TuCht4 and group Ⅳ TuCht10 are involved in mite molting. Suppression of TuCht4 or TuCht10 resulted in high mortality, molting abnormalities and the absence of distinct electron dense layers of chitinous horizontal laminae in the cuticle, as demonstrated by scanning electron microscopy and transmission electron microscopy. The nanocarrier mediated RNAi had significantly higher RNAi efficiency and caused higher mortality. The results of the present study suggest that chitinase genes TuCht4 and TuCht10 are potential targets for dietary RNAi, and demonstrates a nanocarrier-mediated delivery system to enhance the bioactivity of dsRNA, providing a potential technology for green pest management.
摘要：
昆虫几丁质酶（Chts）在蜕皮过程中起着至关重要的作用，通过连续的发展阶段实现持续增长。基于它们与昆虫小鸡的高度同源性，TuCht1（第二组），TuCht4（I组）和TuCht10（IV组）被鉴定，并研究了它们在蜕皮过程中的作用。TuCht1主要在地名阶段表达，而TuCht4主要在若虫阶段表达，在幼虫中TuCht10的表达水平最高。饲用RNAi实验表明，Ⅰ组TuCht4和Ⅳ组TuCht10参与螨蜕皮。抑制TuCht4或TuCht10导致高死亡率，蜕皮异常和表皮中几丁质水平薄片的不同电子致密层的缺失，如扫描电子显微镜和透射电子显微镜所证明。纳米载体介导的RNAi具有显著更高的RNAi效率并导致更高的死亡率。本研究的结果表明，几丁质酶基因TuCht4和TuCht10是膳食RNAi的潜在目标，并展示了一种纳米载体介导的递送系统，以增强dsRNA的生物活性，为绿色害虫管理提供潜在技术。
