College of Life Sciences, Jiangxi Science & Technology Normal University, Nanchang 330013, China.
Institute of Entomology, Jiangxi Agricultural University, Nanchang 330045, China.
Pestic Biochem Physiol. 2024 Jun;202:105962. doi: 10.1016/j.pestbp.2024.105962. Epub 2024 May 16.
Lufenuron, a benzoylurea chitin synthesis inhibitor, is effective against many insect pests. However, the insecticidal activity of lufenuron has not been completely elucidated, nor has its disturbing effect on chitin synthesis genes. In this study, bioassay results demonstrated an outstanding toxicity of lufenuron against Helicoverpa armigera larvae. The treated larvae died from abortive molting and metamorphosis defects, and severe separation of epidermis and subcutaneous tissues was observed. Treatment of 3rd- and 4th-instar larvae with LC lufenuron significantly extended the duration of larval and pupal stage, reduced the rates of pupation and emergence, and adversely affected pupal weight. Besides, lufenuron can severely reduce chitin content in larval integument, and the lufenuron-treated larvae showed reduced trehalose content in their hemolymph. Further analysis using RNA sequencing revealed that five chitin synthesis genes were down-regulated, whereas the expressions of two chitin degradation genes were significantly enhanced. Knockdown of chitin synthase 1 (HaCHS1), uridine diphosphate-N-acetylglucosamine-pyrophosphorylase (HaUAP), phosphoacetyl glucosamine mutase (HaPGM), and glucosamine 6-phosphate N-acetyl-transferase (HaGNPAT) in H. armigera led to significant increase in larval susceptibilities to LC lufenuron by 75.48%, 65.00%, 68.42% and 28.00%, respectively. Our findings therefore revealed the adverse effects of sublethal doses of lufenuron on the development of H. armigera larvae, elucidated the perturbations on chitin metabolism, and proved that the combination of RNAi and lufenuron would improve the control effect of this pest.
灭幼脲，一种苯甲酰脲类几丁质合成抑制剂，对许多害虫有效。然而，灭幼脲的杀虫活性尚未完全阐明，其对几丁质合成基因的干扰作用也尚未阐明。在本研究中，生物测定结果表明灭幼脲对棉铃虫幼虫具有优异的毒性。处理过的幼虫因蜕皮和变态缺陷而死亡，并观察到表皮和皮下组织严重分离。用 LC 灭幼脲处理 3 龄和 4 龄幼虫显著延长了幼虫和蛹期的持续时间，降低了化蛹率和羽化率，并对蛹重产生不利影响。此外，灭幼脲可严重降低幼虫表皮中的几丁质含量，处理过的幼虫血淋巴中的海藻糖含量降低。进一步使用 RNA 测序分析表明，有 5 个几丁质合成基因下调，而 2 个几丁质降解基因的表达显著增强。棉铃虫几丁质合酶 1（HaCHS1）、尿苷二磷酸-N-乙酰葡萄糖胺焦磷酸化酶（HaUAP）、磷酸乙酰葡萄糖胺变位酶（HaPGM）和葡萄糖胺 6-磷酸 N-乙酰转移酶（HaGNPAT）的基因敲低导致幼虫对 LC 灭幼脲的敏感性分别显著增加了 75.48%、65.00%、68.42%和 28.00%。因此，我们的研究结果揭示了亚致死剂量的灭幼脲对棉铃虫幼虫发育的不利影响，阐明了对几丁质代谢的干扰作用，并证明了 RNAi 与灭幼脲的结合将提高对这种害虫的防治效果。
