Zhengzhou Reseach Base, State Key Laboratory of Cotton Biology, Zhengzhou University, 450001 Zhengzhou, China; State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China.
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China.
Pestic Biochem Physiol. 2022 Aug;186:105178. doi: 10.1016/j.pestbp.2022.105178. Epub 2022 Jul 19.
Spodoptera exigua (Lepidoptera, Noctuidae) has been responsible for causing considerable and widespread agricultural losses worldwide. Owing to strong selective pressure, S. exigua showed increased resistance to Lufenuron (LUF). Consequently, RNA interference (RNAi)-based insecticides had more benefits than chemical insecticides. Therefore, to enhance the insecticidal activity of LUF to S. exigua, in the present study, we aimed to elucidate the impact of double-stranded RNAs (dsRNAs) on S. exigua larval susceptibility to LUF. First, the transcriptome of S. exigua was sequenced following the treatment with LUF. By comparing the upregulated and downregulated GO enrichment, chitin binding and chitin metabolic processes were the significantly enriched pathways. According to transcriptome sequencing, 8 genes associated with chitin biosynthesis, 8 chitin degradation genes, and 17 cuticle protein genes were obtained. UDP-N-acetylglucosamine pyrophosphorylase (UAP) and Chitin synthase A (CHSA) showed significantly downregulated expression after treatment with different sublethal doses of LUF. Downregulation of UAP increased mortality from 31.97% to 47.91% when the larvae were exposed to LUF. A significant increase in the mortality of S. exigua from 30.63% to 50.19% was observed following LUF administration after dsCHSA. In addition, the expression analysis of genes associated with chitin biosynthesis was significantly changed after LUF treatment, dsRNAs-RNAi, and their combination (LUF-dsRNAs). Significant differences were observed in the chitin content between the control group at 72 h after treatments. Results of the present study can help further elucidate the understanding of the combined effects of RNAi and LUF on S. exigua. Additionally, this research provides a suitable foundation for future studies with the aim to develop an efficient method of delivery for large-scale pest control in the fields.
甜菜夜蛾（鳞翅目，夜蛾科）在全球范围内造成了相当大且广泛的农业损失。由于强烈的选择压力，甜菜夜蛾对 Lufenuron（LUF）表现出更高的抗性。因此，基于 RNA 干扰（RNAi）的杀虫剂比化学杀虫剂具有更多的优势。因此，为了提高 LUF 对甜菜夜蛾的杀虫活性，本研究旨在阐明双链 RNA（dsRNA）对甜菜夜蛾幼虫对 LUF 敏感性的影响。首先，用 LUF 处理后，对甜菜夜蛾的转录组进行了测序。通过比较上调和下调的 GO 富集，几丁质结合和几丁质代谢过程是显著富集的途径。根据转录组测序，获得了与几丁质生物合成相关的 8 个基因、8 个几丁质降解基因和 17 个表皮蛋白基因。UDP-N-乙酰葡萄糖胺焦磷酸化酶（UAP）和几丁质合成酶 A（CHSA）在用不同亚致死剂量的 LUF 处理后表达显著下调。当幼虫暴露于 LUF 时，UAP 的下调使死亡率从 31.97%增加到 47.91%。dsCHSA 处理后，LUF 给药使甜菜夜蛾的死亡率从 30.63%显著增加到 50.19%。此外，在用 LUF 处理、dsRNA-RNAi 及其组合（LUF-dsRNAs）后，与几丁质生物合成相关的基因表达分析发生了显著变化。在处理后 72 小时，对照组之间的几丁质含量存在显著差异。本研究的结果可以帮助进一步阐明 RNAi 和 LUF 对甜菜夜蛾的联合作用的理解。此外，这项研究为未来的研究提供了一个合适的基础，旨在开发一种有效的大规模田间害虫控制方法。
