虱螨脲对草地贪夜蛾幼虫的毒力及对其几丁质含量和几丁质酶活性的影响
Toxicity of lufenuron and its effects on the chitin content and chitinase activity of Spodoptera frugiperda larvae
王增霞，周 婉，何 灿，黄保宏，胡 飞
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DOI：10.7679/j.issn.2095-1353.2023.121
作者单位：安徽省农业科学院植物保护与农产品质量安全研究所，合肥 230031
中文关键词：草地贪夜蛾；虱螨脲；毒力测定；几丁质；几丁质酶
英文关键词：Spodoptera frugiperda; lufenuron; toxicity bioassay; chitin; chitinase
中文摘要：
【目的】 探究虱螨脲（Lufenuron）对草地贪夜蛾Spodoptera frugiperda的毒力，明确虱螨脲对草地贪夜蛾生长发育的调控机理，为虱螨脲在草地贪夜蛾防治上的科学应用提供依据。【方法】 通过生物测定法研究虱螨脲对草地贪夜蛾幼虫的毒力，进一步利用氨基葡萄糖法和Ｎ-乙酰氨基葡萄糖分别测定在亚致死浓度下草地贪夜蛾幼虫体内几丁质含量和几丁质酶活性，并利用生物信息学分析法从转录组数据库筛选几丁质酶基因进行系统发育分析，然后利用实时荧光定量PCR分析虱螨脲处理对草地贪夜蛾幼虫几丁质酶基因表达量的影响。【结果】 经虱螨脲处理后，草地贪夜蛾幼虫逐渐表现出活动力下降，蜕皮困难，最终畸形死亡。虱螨脲处理96 h后LC20值为0.517 mg/L，LC50值为1.009 mg/L。用亚致死浓度虱螨脲分别处理草地贪夜蛾幼虫48 h和96 h后，几丁质含量和几丁质酶活性显著降低。进化树分析结果显示，从NR数据库筛选出的5条草地贪夜蛾几丁质酶基因为5种不同类型的几丁质酶基因。qPCR分析结果表明，虱螨脲在LC20浓度下对几丁质酶基因表达有显著的激活作用，但LC50浓度对几丁质酶基因的表达有一定的抑制作用。【结论】 虱螨脲对草地贪夜蛾有较强的毒力作用，能够降低草地贪夜蛾幼虫体内几丁质含量和几丁质酶活性，且对几丁质酶基因表达具有显著干扰作用。
英文摘要：
[Objectives] To investigate the toxicity of lufenuron and its effects on the growth and development of Spodoptera frugiperda larvae. [Methods] A bioassay was conducted to investigate the toxicity of lufenuron to S. frugiperda larvae and the chitin content and chitinase activity of larvae exposed to sublethal concentrations of lufenuron were measured using the glucosamine, and N-acetylglucosamine methods, respectively. Bioinformatics was used to screen chitinase genes from the transcriptome database for phylogenetic analysis, after which real-time fluorescence quantitative PCR was used to analyze the effect of lufenuron on the expression of these genes. [Results] Larvae gradually became less active and molting and cuticle development became abnormal. Larvae eventually became deformed and died. The lethal 20% (LC20) and 50% (LC50) concentrations of lufenuron after 96 h were 0.517 mg/L and 1.009 mg/L, respectively. Chitin content and chitinase activity were significantly reduced after 48 h and 96 h exposure to sublethal concentrations of lufenuron. A phylogenetic tree indicates that the five chitinase genes in the NR database are different types. qPCR analysis shows that the LC20 concentration of lufenuron can activate chitinase gene expression, whereas the LC50 concentration can inhibit it. [Conclusion] Lufenuron reduces chitin content, inhibits chitinase activity and disrupts chitinase gene expression, in S. frugiperda larvae. It therefore has potential as an insecticide for the control of this important global pest.